Signs of Spring 2: Plastics!

food waste

Wasted food. Photo by Foerester. Wikimedia Commons

(Click on the following link to listen to an audio version of this blog …. Plastics

Deborah and I have had the same New Year’s Resolution for the past 15 years: don’t waste food! Making sure that we make meal portions that we can eat and making sure that we eat leftovers for dinner and/or lunch was essential. As little food waste as possible was our goal.

This year, in solidarity with the State of Colorado’s ban on single use plastic bags (a law that went into effect on January 1, 2024), new data on the ubiquity of plastic waste in our surroundings and disturbing news stories about how recycling centers were actually sending most “recycled” plastics to landfills, we also resolved to cut down on our use of plastics.

bakelite

Bakelite bangles. Photo by Izzy. Wikimedia Commons

Plastics, as we have discussed several times in this blog space,  are human manufactured materials. They were invented 117 years ago (the first plastic was “bakelite” invented by Leo Baekland in New York in 1907). Plastics are large polymers of repeating organic subunits with very high molecular weights and, depending on the specific building block subunits, a wide range of properties and uses. Most of the building blocks of plastics come from petroleum or natural gas.

Roland Geyer (University of California, Santa Barbara) in a paper published several years ago in Science Advances (July 19, 2017) estimated that since the invention of bakelite we have produced 8.3 billion tons of plastics. Since we make almost 400 million tons of new plastic every year, by now our total tonnage is probably closer to 10 billion tons! That is enough plastic to cover the entire country of Argentina more than ankle deep in plastic materials. Geyer also notes that almost all of this plastic is non-degradable and will, along with all of the rapidly accelerating yearly production of new plastics, be with us for hundreds of years.

Most plastics end up in landfills but many millions of tons a year pollute our oceans, lakes and streams, land masses, and food webs. They are even part of the pollution load in the atmosphere! We are conducting an unintentional, unregulated, global experiment in which we are covering the Earth in plastic and also feeding it to a wide range of birds, fish and mammals (even ourselves!). The world’s oceans contain 150 million tons of plastic, and it is predicted that by 2050 there will be more plastic, by weight, in the oceans than fish.

Mountain of plastic. Photo by Jar-o, Flickr.

Many species of sea birds are known to eat and accumulate plastics. A recent study, published in the Journal of Hazardous Materials (May 15, 2023) noted that sea birds (in this case the flesh-footed shearwater  (Ardenna carneipes)) develop a very distinctive pattern of mucosa and submucosa scarring in their stomachs when they ingest plastics. This syndrome has even been given a name: “plasticosis.”

Plastics out in our environment can be in large, macro-sized forms (like the ocean-transported, plastic debris that I wrote about that befouls the beaches of the uninhabited Henderson Island out in the middle of the Pacific Ocean (Signs of Fall 4, Sept.5 2017).

Even more insidiously, though, plastics can be suspended and transported in both freshwater and marine systems in the form of microscopic pieces. These pieces are classified as micro-plastics (“MP’s”) (which are about 2 micrometers in size) or nano-plastics (“NP’s”) (which are about 500 nanometers in size).  In the water these particles get coated with algae and attract zooplankton and larger consumers (like sea birds and marine mammals).  The surfaces of these plastic particles also attract and accumulate a myriad of extremely toxic pollutants (including heavy metals, dioxins, PCB’s, DDT’s, and PAH’s) which then bioaccumulate in the organisms that ingest the plastic materials.Nano-plastics also are found in our foods and beverages.

bottle

Photo by Jm51. Wikimedia Commons

I talked about the prevalence of NP’s in beer and sea salt in Signs of Fall 12 (November 22, 2018), and a recent paper in the Proceedings of the National Academy of Sciences (January 8, 2024) looked at the amount of MP’s in bottled water (100,000 MP particles in every liter!). This paper also discussed some of the possible consequences of ingesting these MP’s including an increased incidence of colorectal cancers (especially in young people) and increases in Crohn’s disease and ulcerative colitis.

Another paper published last year in the Journal of Hazardous Materials (January 15, 2023) determined that humans consume about 5 grams of MP’s per week. These MP’s alter the community of colonic microorganisms (decreasing several beneficial microbes and increasing several pathogenic microbes). These MP’s are also absorbed into the body and found circulating in the blood stream and accumulating in a number of organs of the body (including the liver, spleen, lungs and placenta).

Another study published in Cell Reports (April 4, 2023) showed that NP’s in the diet triggered the activation of gut macrophages and stimulated the synthesis of an intestinal cytokine (Interleukin 1 (IL-1)). IL-1 acts to modulate the activity of the immune system and regulate inflammation. This “gut” IL-1 entered the blood stream and was detected in the brains of study animals where it stimulated microglial activity and activated the helper T-cell, Th17. Th17 produces an array of cytokines that trigger immune reactions to infectious agents (like bacteria). They also are significant immune modulators in a number of autoimmune diseases. The impact of this IL-1 and Th17 activity in the brain was a notable decline in cognitive and short-term memory.

And, a paper just published in the New England Journal of Medicine (March 7, 2024) examined the plastic content (MP’s and NP’s) of the fatty plaque removed from patients’ carotid arteries. Those patients with the highest amounts of plastics had significantly greater chances of stroke, heart attack or death from any causes during the follow-up months after the operation than those patients who had no plastic in their fatty plaque.

You don’t want plastics in your body!

Singl use plastic bages. Photo by Divotomezove. Wikimedia Commons

So, what have Deborah and I done to reduce our use of plastics?

  1. We now buy our orange juice as frozen concentrate instead of ready-to-drink juice in plastic jugs.
  2. We now only buy milk in half-gallon, cardboard containers instead of the gallon, plastic jugs.
  3. We only buy eggs in cardboard egg cartons.
  4. We stopped buying lettuce and other salad veggies pre-packaged in plastic containers. Now we buy loose produce and bring it home in our re-useable, cloth bags.
  5. We buy bulk kitty litter from the local pet store and fill-up our reuseable litter pail as needed.
  6. We buy meat and chicken etc. directly at the meat counter and get it wrapped in paper.
  7. We buy yogurt in as large a container as possible instead of whole slew of small containers.
  8. We continue to use our re-useable water bottles and also our reuseable grocery/shopping bags.
  9. If we have soda, we buy it in recyclable, aluminum cans instead of plastic bottles or jugs.
  10. Laundry soaps, dishwasher detergents, shampoos and contitioners are now available in paper packed and bar forms. No plastic bottles!
  11. When we go to a restaurant, we take our own, reuseable containers for any leftovers.

It is hard to completely eliminate plastics from your life, but we are working toward a more sustainable home ecosystem!

By the way, the new Colorado law banning the distribution of single use plastic bags is being widely ignored by many of the stores in our area! There are still thousands of available bags at the checkouts of our grocery stores and for delivery of take-out food from restaurants. Things change, but slowly!

 

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Signs of Spring 1: The Human Microbiome!

ecoli

E. coli at 1000x. USDA. Public Domain

(Click on the following link to listen to an audio version of this blog … Human microbiome (1)

Studies of the microorganisms that live on and in the human body have been going on since that late 19th Century. Escherichia coli was first isolated from the colon and described in 1888. Bifidobacteria was described in 1892. The beneficial influences of gut microorganisms were being discussed in 1900, and the specific impacts of microbially generated metabolites in the colon were subsequently outlined.

Technical innovations in the past 25 years, though, have made the study of our microorganisms (i.e. the “human microbiome”) much more precise and also quicker and easier to accomplish. In particular, methods analyzing the nucleic acid (DNA and RNA) sequences in sample materials (feces, tissue scrapings, sweat, tears, skin oils etc.) and relating these nucleic acids to specific  bacteria, fungi, archaea and viruses have allowed the wide-spread exploration and description of the human microbiome. These culture-independent methods have led to an explosion of ideas, studies and published papers.

At first, the number of cells in the human microbiome was thought to be some 10 to 100 times the actual number of cells in the human body. More precise studies, though, indicate that numerically there are probably about the same number of microbiome cells (about 38 trillion) as there are cells in all of the tissues and organs of a human being (about 30 trillion cells). The genetic information contained in these two groups of cells, though, is several orders of magnitude different (the human genome consists of 20,000 genes while the collective genomes of the human microbiome contains 2,000,000 genes).

A large number of factors influence the structure of a person’s microbiome. Hygiene, probiotics, prebiotics, overall diet, antibiotics, disease, exercise and age all alter the microbial community of the microbiome. One of the most remarkable insights from the microbiome research of the past 25 years has been the realization that every individual has their own unique microbiome community! The search for a “core” microbiome common to all humans has not been successful!

microbiota

Coevolition of human microbiome. G. Berg et al. Wikimedia Commons

This lack of a core microbial community makes studies exploring the impact of diseases on the body’s microbial community (or, to reverse that thought, studies on how particular aspects of the body’s microbial community might affect (or cause) disease) very difficult. If everyone has a unique microbiome, changes due to or causing illness become very hard to reliably detect or describe!

There is, though, a generalized response of the gut microflora to inflammation not only in the colon but anywhere in the body. Inflammation decreases the number and diversity of colonic microorganisms which may, then, affect other organ systems of the body.

There are a number of diseases that appear to have connections to the human microbiome: Type 2 diabetes, obesity, inflammatory bowel diseases (Crohn’s Disease and ulcerative colitis). Parkinson’s Disease, depression and several types of cancer. It is not clear, though, if these connections are causal or if they are simply correlations to changes in the body’s homeostasis due to the disease..

newborn

Human newborn. Photo by Ernest F. Wikimedia Commons

The human microbiome begins to form at birth. A new-born infant acquires microbial symbionts from their mother and from their immediate environment. Vaginally delivered newborns are well bathed in microbial-rich secretions from their passage down the  birth canal. Caesarian-delivered newborns are not heavily exposed to maternal microbial populations and are much more active in acquiring microbes from other areas of their environment. A paper published in Nature (October 3, 2019) found that C-section newborns had colonic microbiomes that were up to 30% hospital-acquired bacteria (including a number of opportunistic pathogens)! Breast-fed infants, however, whether they were birthed vaginally or via Caesarian-section,  acquire significant microbial symbionts from their mothers.

Differences between the microbiomes of vaginally-delivered and C-section infants disappear by one year of age. During this first year of life, though, there can be significant differences in an infant’s metabolic activities depending on what type of microbiome they possess. In the first year of life the immune system undergoes significant changes and steps in its maturation cycle, and the infant’s microbiome seems to play a significant role in these immune system modulations. The higher rates of asthma and allergies in children who were C-section babies are important observations that support the idea that the altered microbiome in C-section infants acts to inhibit normal immune activity. C-section babies also have higher rates of Type 1 diabetes which may reflect another level of immune disfunction.

basset hound

Baby and basset hound, Photo by Gmip. Wikimedia Commons

The Hygiene Hypothesis states that children not exposed to normal infant diseases, environmental debris and immune triggers are more likely to have underdeveloped (“uneducated”) immune systems. These children have higher rates of asthma, eczema, and allergies. It is possible that that system that is at least in part mediating this Hygiene Hypothesis impact is the infant’s microbiome. If an infant is exposed to an abnormally sterile environment, they will not be able to construct a normal microbiome.

The onset of the COVID-19 Pandemic had huge impacts on many aspects of our biological, social and economic worlds. In a study recently published in Scientific Reports (August 16, 2023) a research group in New York City monitored the development of infant microbiomes in 54 children born at onset of the pandemic. Pandemic restrictions in New York City were very severe, and all of these newborns were kept quite isolated from contact with anyone who was not in their immediate family. This very unnatural restriction in contact with other people had a remarkable impact on the microbiomes of the infants. Overall, the diversity of their microbiomes was significantly decreased from previously measured “normal” levels. Future studies on these children are needed to determine if they have a greater propensity toward asthma, allergies and other immune system disorders.

The human microbiome has been recognized and studied for over 100 years. Recent technological breakthroughs that enable researchers to make culture-independent analysis of the microbiome has led to an explosion of studies and published papers. There are, though, many fundamental things about the human microbiome that we do not know. Is their a “human core” of microbial species that define all human microbiomes? Are there ways to get “good” microbial species established in the human colon? Are there ways to encourage “good” microbial species in the colon to proliferate? And, which microbial species in the human colon are “good,” and what exactly do they accomplish in the body?

Lot’s of really great questions!

 

 

 

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Signs of Winter 11: The Ecology of Sourdough!

bread

Breads, Photo by 3268zauber, Wikimedia Commons

(Click on the folowing link to listen to an audio version of this blog …. Ecology of Sourdough

Bread making is a craft that was first developed in Neolithic Asia some 14,000 years ago. The leavening agents used in breads (i.e. the things that make the bread rise) were originally and until relatively recently, natural, microbial systems. Today, most breads are made with specialized bread yeasts. Those breads that still rely on natural, microbial systems for leavening are often referred to as “sourdough” breads.

When a baker makes a sourdough starter, they are generating a complex microbial ecosystem that will almost immediately begin to undergo successional changes. “Succession,” as we’ve talked about in many previous blogs about macro-ecosystems like grasslands and forests, is the observed change in the species structure of an community over time. Some species decrease, some species increase, some species may even come into the community from surrounding ecosystems. The changes in species structure of the community is caused by the activity of the organisms in the community itself which then alters the conditions of the system’s environment.

bread

Home_made_sour_dough_bread, Photo by Tomascastelazo, Wikimedia Commons

So, in a sourdough starter instead of seeing grass, and trees and shrubs and weeds interacting and competing for space and resources, we see bacteria and single-celled fungi called yeasts competing for the system’s limited resources. As the bacteria and yeasts grow and metabolize the flour, they change the physical and chemical nature of starter ecosystem and in doing so change which microbial species will be most likely to flourish in the community.

The rise and fall of species in a sourdough starter continues as long as there are carbohydrate energy molecules left in the system! In order to keep the starter ecosystem “alive,” the baker must propagate (or “backslop” or “seed” or “feed”)  the starter (i.e. they remove a good part of the old starter and replace it with fresh flour and water). This disturbance suddenly alters the microbial ecosystem of the starter, and stimulates succession to begin anew in the fresh materials.

Starters stored in the refrigerator only need to be seeded when they are brought out into room temperature prior to use. Starters stored at room temperature, though, will probably need to be seeded every day! Before a starter is used to make a loaf of bread, its volume needs to be doubled by a fresh propagation. Then, half the starter can be used to make the loaf while the other half is stored for future use.

starter

Sourdough_starter, Photo by Jeuwre, Wikimedia Commons

Every starter begins with a unique microbial community.  The bacteria and fungi living in the flour and water of each starter base are unique. The type and age of the flour, the area where the flour was grown and where it was milled all contribute very specific microbial species to the starter. Also, the bowl or other vessel in which the starter is contained will contribute some unique microbial organisms. Further, the air in the bakery or kitchen and the baker’s own skin and breath will add some particular bacteria and fungi to the starter community. A starter made in a mechanical bread machine will be different than a starter made by hand!

Probably the least important factor in this unique construction of the starter community is the geographical area in which the starter is being made. These geographic designations, though, (like San Francisco, Alaska, Chicago, etc.) are often the commercial labels appended to pre-made sourdough starter kits. This labeling implies a locational influence that, in actuality, is quite slight. The overwhelming influence of the microbes in the flour, in the water, in and on the baker and in the kitchen or bakery are only minimally altered by microbes from the outside air.

The species diversity of the initial starter is relatively high. There are typically hundreds of bacterial species and they quickly grow into many billions of bacterial cells for every teaspoon of starter material.  There will also be several dozen types of yeast in the beginning starter, and several million yeast cells per every teaspoon.

As the starter “matures,” the number of bacterial and yeast species decrease although the overall cell numbers of each stays relatively constant or even grows. Bacterial species that produce acids (and species which can tolerate acidic conditions) are favored in the changing microbial community. In particular, lactic acid producing bacteria (LAB’s) become dominant. There are 60 common species of LAB found in sourdough starters. A given starter, though, typically contains only 1 to 3 of these species. Most common are those LAB’s referred to as “heterofermentative.” These bacteria not only make lactic acid as a consequence of their energy metabolism but also acetic acid, ethanol and carbon dioxide. These heterofermentative LAB’s will not only generate a good portion of the leavening gases for the loaf, but also contribute to the complex array of flavors to the developing bread.

starter

Sourdough_Starter, Photo by veganbaking.net, Wikimedia Commons

Also in the starter microbial community are acetic acid producing bacteria (AAB’s). AAB’s are almost always less abundant that LAB’s in the starter system but increase in proportion particularly if the starter is incubated at cool temperatures. AAB’s produce the acetic acids that gives sourdough bread its distinctive “tang.” If AAB’s are present in too great of numbers, though, or if certain, odd AAB species are present, the starter may generate chemicals that have unpleasant odors, and these chemicals can ruin the taste of the bread.

The yeasts function in the starter is to make carbon dioxide and act as the prime leavening agent for the bread. There are 40 different species of yeast that have been isolated from sourdough starters, but a typical starter only has 1 or 2 yeast species in it. Sometimes, if the LAB’s are very abundant and active, they can cause an acute rise in starter acidity, and then a starter may contain no yeast at all.

Yeasts produce an array of allelopathic chemicals (i.e. chemicals that inhibit the growth of other organisms) that they used to establish their niches in the starter community. It is interesting to note that sourdough starters made by female bakers almost always contain different yeast species than sourdough starters made by male bakers! This emphasizes the influence of the baker’s own microbiome in generating the starter’s microbial community!

yeast

Yeast cells. Photo by Masur, Wikimedia Commons

The successional sequence of microbial community change in a sourdough starter depends greatly on the temperature in which it is being kept. At cool (refrigerated) temperatures, the rate of microbial growth and change will be quite slow. At high temperatures, the rate of microbial growth and change will be very rapid. At room temperature, the sequence might follow a time line like this:

First two hours: Each starter has its own unique, starting microbial community. Community diversity (especially driven by species richness) is as high as it will be in the succession sequence. The starter contains hundreds of bacterial species and dozens of species of yeast.

Hours 4 to 10: LAB’s become increasingly active lowering the pH of the starter. Bacterial species unable to tolerate acidic conditions are eliminated from the community. Not all yeast species can tolerate the lower pH of the system, and they are also eliminated. Surviving yeast species may generate allelopathic chemicals which can further eliminate sensitive bacterial species. AAB bacteria slowly begin to grow. The starter at first tastes and smells floury and bland. Little production of carbon dioxide gas (few bubbles). Starter is dense. A blob of starter will sink in a dish of water.

Hours 10 to 16: Microbial diversity is reduced but total numbers of microbial cells is high. There are 1 to 3 dominant LAB species in the starter and 1 or 2 (or zero) yeast species. The microbial system is very actively breaking down carbohydrates in the starter. Abundant carbon dioxide being generated. The starter tastes and smells sweet with a sour tint. Lots of carbon dioxide gas production (lots of bubbles). The volume of the starter has significantly increased and, so, its density has decreased (a blob of starter will float in a dish of water).

Hours 16 to 24+: Food resources in the starter (carbohydrates in the starter flour) begin to decline. Microbial activity also decreases. Microbial numbers decline. Carbon dioxide production declines. Starter will “die” if it is not rejuvenated by propagation. The starter tastes and smells sour and vinegary (acetic acid!). Some gas is being still produced (a few, very small bubbles). Starter shrinks down and gets dense. A blob of starter will sink in a dish of water.

Starters, then are most effective bread leavening agents when they are between 10 and 16 hours old. Propagation is then needed to keep the starter microbial community alive and functioning. By delaying propagation too long past the 16 hour activity peak or by propagating too soon before the microbial community is fully mature, a baker can significantly alter the starter microbial community and have serious impacts on the effectiveness and quality of the starter breads.

So, when you are baking sourdough breads you are working with a living, changing microbial ecosystem! A successful sourdough baker must recognize the activity and the timing and the chemical nature of their starter in order to successfully use it as a leavening agent!

 

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Signs of Winter 10: What is Happening to Our Food?

food

Good_Food_Display, Phto by NIH, Public Domain

(Click on the following link to listen to an audio version of this blog … What’s happening to our food?

There are many things about our food that worry us: overly processed  ingredients, excessive levels of fats and sugars and salts (often added to trick us into eating more), added palm oils, chemical preservatives and artificial colorings. Recent research into the chemical composition of food, though, suggests that there might also be an on-going, “natural” process that is reducing the quality of foods we eat.

Quality of food can be described in many ways. Subjective features (taste, aroma, texture etc.) may be of prime importance to a consumer, but they are very difficult to measure or standardize. Objective features of a food (like number of calories per gram, amount of fiber and levels of macro-and micronutrients) are much easier to quantify and compare.  A great deal of data about the nutrient composition of our foods has been gathered throughout the 20th and 21st Centuries and is available in several large, governmental data bases.

food

Fresh_cut_fruits_and_vegetables. Photo by USDA, Public Domain

One published study (British Food Journal , July 1, 1996) examined the food tables compiled by the government of the United Kingdom (UK). These tables recorded the annual analysis of the mineral content of twenty fruits and twenty vegetables. The paper compared data collected from fruits and vegetables in the 1930’s to the data collected in the 1980’s. In both fruits and vegetables total dry matter decreased and moisture content increased over the fifty year time span. In vegetables, there were significant declines in calcium, magnesium, copper and sodium. In fruits, there were significant declines in magnesium, iron, copper and potassium.

In another paper by the same author as the above, 1996 study, the mineral and micronutrient composition of UK fruits and vegetables from 1940, 1991 and 2019 were examined. This study (published in the International Journal of Food Science and Nutrition (October 15, 2021)) showed that all minerals and nutrients in the fruits and vegetables analyzed decreased in the 80 years between 1940 and 2019 with the exception of phosphorous. In particular, sodium levels declined by 52%, iron levels declined by 50%, copper levels declined by 49% and manganese levels declined by 10%.

food

Fruit_and_vegetables, National Cancer Institute, Public Domain

A similar study in the United States explored the annual data collected by the U. S. Department of Agriculture on the nutrient composition of 43 types of garden-grown vegetables from 1950 to 1999. This study (published in the Journal of the American College of Nutrition (June 18, 2013)) found significant decreases in the vegetables’ protein, calcium, phosphorus, iron, riboflavin and Vitamin C over the fifty year time period.

The authors of these three studies and a number of reviewers and critics of these papers point out that the information in the government data tables may not have been collected in a consistent manner each year, thus making year to year comparisons very difficult. There was no regularity in the sources for the fruits and vegetables analyzed, no consistency in the sites in which they were grown. Further, the ripeness or age of the fruits and vegetables analyzed was not standardized, and the analytical methods used to evaluate the fruits and vegetables changed over the decades of the data collection.

In spite of these confounding difficulties, the authors of these three papers are adamant that something is happening to our fruits and vegetables. Whatever this process is, it is causing a reduction in the mineral and micronutrient composition of these important foods!

flour

Wheat-flour. Photo by ارون يحيى Wikimedia Commons

Carbohydrates typically make up a much larger percentage of most peoples’ diets than do fruits or vegetables. Wheat and rice, in particular, are major calorie sources for most of the world’s population. Wheat makes up 25% of the average daily caloric intake for people in the United Kingdom, Europe and the United States, and rice makes up just over 29% of the average daily caloric intake for individuals in most Asian countries. It is estimated that half of the world’s population (some four billion people) rely on rice as a staple food. It is also important to note that the poorer the population cohort is within these wheat-dominated and rice-dominated societies, the greater the daily percentage of calories they are likely to take from carbohydrate-based foods.

In 1843, John Bennet Lawes began a study at his estate in Hertfordshire, England in which he examined the effects of  different levels of mineral fertilizers and manures on the productivity of grain crops (wheat and barley). Each year, Lawes carefully collected soil samples and mature grain samples from his wheat and barley fields. Lawes’ study continued after his death, and his estate eventually became the Rothamsted Experiment Station (now called Rothamsted Research) one of the world’s premier agricultural research institutions. Scientists at Rothamsted have continued Lawes’ study on his wheat fields and now have 180 years of data (and over 300,000 soil and grain samples) from which they can very closely assess the nutrient and mineral content of the wheat and the soils in which the wheat was grown.

rothhampsted

Plaque at Rothamsted, Photo by Yerpo, Wikimedia Commons

Analysis of these samples indicates that between 1845 and 1967 the levels of minerals and micronutrients in the Rothamsted wheat were very stable. After 1968, though, levels of zinc, copper and magnesium began to decline. Analysis of the soil samples, though, showed no decline in any mineral nutrients over the 180 years of the study.

What could be the possible reasons for these very precisely observed declines in the micronutrient composition in the wheat or the apparent declines in micronutrients in the fruits and vegetables?

One hypothesis suggests that the development of new, faster growing, higher yielding varieties of these crops may be causing the changes in nutrient composition. For wheat, these new varieties were part of the “Green Revolution” that radically changed agriculture and substantially increased crop yields starting in the mid-Twentieth Century. Possibly these new varieties of crop plants were more focused on accumulating carbon and biomass than they were on gathering micronutrients.

wheat

Wheat_close-up, Photo by user.Bluemoose, Wikimedia Commons

Another suggestion concerned the effect of increased atmospheric carbon dioxide on the growth rates and patterns of these crop plants. Atmospheric carbon dioxide has increased from 316 ppm in 1959 to 424 ppm in 2023! Most plants grow more rapidly at higher carbon dioxide levels, and, because they take in sufficient amounts of carbon dioxide for their photosynthetic metabolism over shorter periods of time, tend to keep the stomata in their leaves closed for longer portions of the day. Keeping the stomata closed reduces transpirational water loss from the plant which then reduces the flow of nutrient-rich soil water into the plants roots. This decline in nutrient uptake may explain the observed decline in micronutrient levels in wheat and also in the fruits and vegetables.

rice

Rice_paddy. Photo by Takeaway. Wikimedia Commons

Experiments conducted on rice have shown similar micronutrient declines when the rice was grown under conditions of higher atmospheric carbon dioxide. On average, both rice and wheat showed 5% reductions in micronutrients when grown at higher (i.e. present day) levels of atmospheric carbon dioxide. In affluent societies, these micronutrient deficiencies are easily made up by dietary supplements or direct enrichment of processed foods. In less affluent societies, though, supplementation or enrichment is not likely to occur, and, as I mentioned earlier in this essay, the less affluent a group of people are, the greater they rely on carbohydrates for their dietary energy. These micronutrient declines in rice and wheat  are going to hit poorer societies very hard and very quickly. Worldwide, it is estimated two billion people have diets deficient in micronutrients. This number is expected to grow over the coming decades.

The physical effects of Climate Change are clear to almost everyone. Sea levels will rise and coastal regions will be flooded. Weather patterns will change affecting wild ecosystems and also agroecosystems. Tropical diseases will spread into higher latitudes, and wildfires will become more common and more intense. Some places on Earth will become uninhabitable sending large numbers of people off on quests to find new places to live. The political and social stresses of these climate-triggered mass migrations of people are already being felt in Europe and in the United States.

To underline this ongoing reality of a changing climate, this past year, 2023, was the warmest year in human recorded history. And now, we learn that the higher atmospheric levels of carbon dioxide may even be changing the way plants grow! It may be changing the very essence of our food supply! What next?

 

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Signs of Winter 9: Goldfish Everywhere!

goldfish

“Goldfish” by H. Matisse, Henri-Matisse-Pushkin-Museum, Wikimedia Commons

(Click on the following link to listen to an audio version of this blog…. Goldfish Everywhere

Eight years ago I came across an article in the New York Times that maintained that goldfish (Carassius auratus) were, quite possibly, the most dangerous and destructive exotic, invasive species affecting our aquatic ecosystems today!  That article inspired me to write a blog about the environmental impacts of feral goldfish (see Signs of Fall 7, October 20, 2016).

My personal experience with goldfish goes back to the mid-1950’s. My brother and I had pet goldfish (named Christopher and Napoleon) whom we loved far too much. We would put the fish in our pockets and take them for walks outside. Our mother repeatedly recovered the gasping fish from our pockets and put them back in the small fish bowl. They always recovered until, at last, they didn’t.

Public Domain

In the early 1990’s. I bought a ten gallon aquarium for my children and then took them to the pet store to let them pick out two goldfish each. At the pet store neither child noticed that the tank from which they were going to make their selections was labeled “feeder fish.”  These fish had a very short expected life span and were destined to be given to larger, carnivorous fish as meals and snacks. The four fish they picked out were very distinctively colored and patterned so it was easy to tell them apart.  They were named according to a popular cartoon video of the time (“The Land Before Time”) so, without any sense of irony at all we had goldfish named  “Little Foot,” “Big Foot,” “Sara” (which was actually “Cera” from the triceratops in the cartoon), and, in a return to goldfish standard names, “Goldie.” Big Foot, because of her great appetite and rapid growth rate eventually came to be called “The Hog.”

The four fish were wonderful. All four grew into substantially sized individuals (Hog, of course, was the largest). They all would have grown even larger if I had put them in a larger aquarium (and this is a characteristic of the species that we will come back to in a few minutes!). Watching the fish tank was almost as good as watching television (our cats actually seemed to prefer the tank to any of the TV shows or video cartoons regularly shown in our living room).

Little Foot, Hog, Sara, and Goldie lived for just over ten years, and many people have expressed surprise that goldfish were able to live that long (cleaning the tank every week help to keep their environment free of toxins and pathogens. Goldfish very actively befoul the water in which they live (a very important point when we start talking about goldfish in the wild)). Goldfish kept in very small “bowls” have vastly shorter lives because of their constant exposure to their own waste. Goldfish taken for walks, though, have even shorter life spans.

Photo by R. Pederson, Free Stock Photos

Ten years is not really an unexpected time frame for goldfish. They can live for up to twenty years in the wild or up to thirty years in captivity. The way we have been exposed to goldfish, though, has not stressed their amazingly long life spans. Instead, starting with U.S. government (Commission on Fisheries) programs that gave away goldfish to Washington D.C. residents back in the late 1800’s (over 20,000 free fish a year!), and continuing on to every carnival or fair that had glass bowls and plastic bags of goldfish for game prizes or giveaways, goldfish have been presented to the public as a disposable ornamentation, and this brings us back to discuss some of their characteristics that make them such a dangerous exotic invasive species.

As we mentioned before goldfish will grow to a size that fits the environment in which they live. In a small aquarium, the fish will stay small. In a larger aquarium, the fish will get larger. If a goldfish, though, is released into a pond or a river, they can really exert their growth potentials almost without limits! Four pound goldfish, sixteen inches long and bigger in circumference than footballs are regularly found in the wild! And, with humans thinking of goldfish as disposable knick-knacks, many of them have been thoughtlessly discarded into wild ponds and streams!

goldfish

Feral goldfish, Photo by J. Kusack, Wikimedia Commons

The behavior of the feral goldfish in their habitats is quite destructive. They swim just above the soft bottoms of their rivers and lakes and uproot aquatic plants and roil up sediments causing the water to become turbid and throwing its nutrient composition out of balance. Out of control algae growth often follows (further spurred on by the nitrogen rich excretions of the goldfish themselves). The goldfish eat everything (especially small invertebrates and fish eggs) and destroy established food chains and reproductive cycles. They can also transmit a number of exotic parasites and diseases which further decimate other fish in their streams and ponds.

Female goldfish can breed several times a year and can annually produce up to forty thousand eggs! Goldfish can also interbreed with many species of wild carp and generate an invigorated array of hybrid species. A good friend of mine grew up in New Jersey and spent many hours fishing the abandoned ponds around his home. Carp were the most common fish caught and the hooking of a “pure goldie” (a carp with solid, goldfish orange coloration) was an acclaimed achievement!

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Goldfish. Photo by ぱたごん. Wikimedia Commons

Goldfish are also very active swimmers. A single individual can regularly swim many hundreds of yards up and down a river each and every day. One monitored, feral goldfish swam over 140 miles along a river during an observation year! Goldfish are also able, possibly instinctively, to find suitable spawning habitats in which their offspring have very high probabilities of success and survival. Also, most of the freshwater lakes and ponds lack predacious fish large enough to eat the larger goldfish. As more and more goldfish survive to breeding age, the rate of their population growth becomes exponential!

Goldfish also tolerate low oxygen levels in their aquatic habitats and are quite resistant to chemical pollutants. They can thrive in a very wide range of environmental temperatures, and seem almost perfectly pre-adapted to our increasingly warm, increasingly polluted freshwater ecosystems!

The other characteristic of goldfish that add to their potential to be an extremely destructive, invasive species is their intelligence. They can be trained to do complex tasks and even to recognize and respond to different pieces of music! The Times article mentioned an engineer from Pittsburgh who trained his goldfish to push soccer balls into nets. While the abilities to play soccer and to tell Mozart from Beethoven are not direct survival aids in the wild, the high cognitive skills displayed by this species make it an efficient problem solver and rapid learner and a formidable adapter to almost any ecological milieu.

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Goldfishes, Photo by Tieffieger, Wikimedia Commons

A recent paper published in the Journal of Great Lakes Research by a scientific team primarily from Fisheries and Oceans Canada described the annual movements of feral goldfish in Hamilton Harbour in the western end of Lake Ontario. Hamilton Harbour, in spite of its impressive and almost regal-sounding name, is the most environmentally degraded area in all of the Great Lakes. A century of accumulation of massive levels of industrial and municipal pollution has made Hamilton Harbour a near biological dead zone: except for feral goldfish, of course!

The Fisheries and Oceans Canada team implanted sensors in 19, large adult goldfish and tracked their locations through a year. They found that the goldfish stayed in deep water over the winter but then came up to the warmer shallows just before they spawned. That knowledge will help fish managers locate and capture the goldfish, hopefully, before they can successfully reproduce.

One of the Fisheries and Oceans Canada team remarked that there were millions to tens of millions of goldfish in the Great Lakes, and their numbers are growing every year. As the lakes heat up due to Climate Change, the goldfish may someday be the only fish still alive!

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Pezz at the back door. About to meet her squirrle. Photo by D. Sillman

Last week was House Cat Day! Our cat, Pezz, help us to celebrate this special day of prognostication! Deborah opened the back door and let Pezz walk out onto the patio. It was a warm, sunny day and Pezz boldly turned to her right and held her head up sniffing the distinctive Greeley air. Then one of our backyard fox squirrles, seeing an apex predator entering his sunflower seed feeding area, began to chatter and fuss from its perch on the fence. Pezz took a quick step toward the fence but realizing that there was no window between her and the obviously crazed wild animal, turned around and raced back into the house. She didn’t see her shadow, but she did see her squirrle! Prediction: six more weeks of winter (just the opposite of that Pennsylvania woodchuck!)!

 

 

 

 

 

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Signs of Winter 8: House Cat Day 2024!

Pizo in her natural habitat. Photo by D. Sillman

(Click on the following link to listen to an audio version of this blog …. Housecat Day 2024

Eleven years ago I wrote about Groundhog Day and suggested that we change this early February day-of-prediction to focus not on an animal that should be sound asleep in his grass-lined burrow dreaming of gardens to ravage, but rather on an animal with whom we could more naturally base an ecologically or culturally significant day of hope for the coming spring.

I went through the pluses and minuses for using a number of different species for our new holiday including robins, bumblebees, scarlet tanagers and killdeers. Each of these animals had features that positively reflected the coming spring, but none of them matched up to the intent and timing of this odd, mid-winter holiday.

I also thought about using earthworms or the early spring butterflies (mourning cloaks and spring azures), but the timing of their activities were too close to the actual onset of spring! These animals wouldn’t get active soon enough to stimulate the anticipation and buzz for the joyous coming of the new season.

Four years ago someone suggested that stink bugs emerging from their hibernation hideouts in our houses might be a “good” sign of spring. I am of the opinion, though, that stink bugs are not a “good” sign of anything and am not seriously considering that well-intentioned but obviously misguided suggestion.

Bella

Bella. Photo by M. Hamilton

Taking all of this into consideration, I have again settled on what was, to me anyway, the most logical and most reliable and most available indicator species among us. That species, of course, is the housecat (Felis catus).

Cats are the most popular house pet in the United States (the Humane Society estimates that there 74 to 86 million house cats in the U.S. (as compared to “only” 70 to 78 million dogs)). As I wrote in my November 24, 2016 blog (“Our Other Best Friend”) and also in my recent January 18, 2024 blog (Signs of Winter 6, “Cats are Perfect”) cats have a complex relationship with humans and may be the only animal species that has chosen us as a co-evolutionary partner rather than vice-versa (hence the hypothesis that cats are not really domesticated at all but are wild animals exploiting our habitats and resources!). The resemblance of domesticated cats to their closely related wild species, the focus of many cats on places rather than people, and their perceived aloofness and self-absorption are factors that cause people to have intense feelings (both positive and negative) about cats. On the distinctly positive side of feelings for cats, the English philosopher John Gray in his recently published book (Feline Philosophy: Cats and the Meaning of Life) suggests that cats hold the secret to a well-live human life! How can we doubt philosophy?

A cat’s inherent love of sunshine and warmth, though, make them a perfect biological agent to help us predict the nearness of the coming warm seasons! And, since they are living in our houses year round, they are available for predictive experimentation!

mazie

Mazie. Photo by D. Sillman

So, eleven years ago on February 2, 2013 I took one of my cats, Mazie, out into the snow-covered front yard in Pennsylvania (I tried to take both of my cats, but my other cat, Taz, sensed that something was up and disappeared into one of her magical hiding places somewhere in the house). I put Mazie down in the yard (on a nice dry towel!), and left the front porch door open. If Mazie ran for the porch, then we would have six more weeks of winter. If she stayed on her towel or started walking around in the yard thus avoiding a dash back into the house, then spring was just around the corner.

I was amazed how fast she ran back into the house! But, that year the weather suddenly turned warm. March temperatures set record breaking highs (I even remember a day when it nearly got up to ninety degrees!).  Maybe our predictive model was not articulated correctly.

mazie

Mazie in snow on Housecat Day. Photo by D. Sillman

In 2014 and 2015 I followed the same experimental procedure, and Mazie, as I reported in this blog, responded with equal speed and agility and got back into the house almost before Deborah could take the lens cap off of her camera. In both of these years winter hung on grimly well into March. Mazie’s predictions, then, fit the observed phenomenon.

In 2016, though, Mazie’s response to the front yard was entirely different. She stepped off her towel and explored the front flowerbed, jumped at some little Pardosa spiders that were running around in the grass and seemed to enjoy herself very much. The early onset of spring that this behavior predicted came about! We had a mild, pleasant March and April and eased our way into a warm, early summer.

In 2017  Mazie not only ran back into the porch but she headed straight for the basement and hid in a box in the furnace room for several hours! Her reaction, though, did not match the resulting weather as both February and March had average monthly highs of 66 and 67 degrees! Definitely an early (and sustained) Spring!

In 2018, Mazie ran from the cold and snow and predicted six more weeks of winter. The rest of February was a roller coaster of temperatures bouncing from the teens all the way to 77 degrees (on Feb 20)! March, then, was cold and snowy but finally finished up in the 60’s. Sounds like Mazie nailed her prediction again!

taz

Taz and friend. Photo by D. Sillman

In 2019, Mazie took control of her House Cat Day performance. Just before 2 pm she went to the front door and meowed to go outside! (we were waiting for the warmth of the day to build up before we took her out!). Deborah opened the door and Mazie walked out the door, down the deck stairs and out into the snow covered yard. She then went under deck and spent the next half hour exploring! This is the most “Spring Positive” reaction she has ever shown! Mazie predicted the immanent onset of Spring!

Observations of Feb and March 2019: first two weeks of Feb were warm, then after a cold spell the last week of Feb also warmed up. Then we had another cold spell until the second week of March where we hit (on Thursday March 14) 77 degrees! After that the highs stayed in the 50’s through the rest of March and the in the 60’s in April.

Overall, Feb/March 2019 was wet (almost 7 inches of rain) and more warm than cold.

Binx

Binx and Mora. Photo by M. Hamilton

We got about an inch of snow the night before the 2020 House Cat Day event, and it continued to snow through the morning. I was a bit worried about Mazie’s reaction to the outside world, but, in Pennsylvania 2020, the snow melted quickly and there was sunshine and 52 degrees by 3 pm. We opened the deck door for Mazie and she stepped boldly out. A gust of wind hit her in the face, but she shook that off and walked slowly down the stairs into the side yard. She walked on top of the landscape timbers that edge Deborah’s perennial flower bed like it was a balance beam and then stepped off into the wet grass of the yard. She sniffed the air and did not even look back at the deck. She stayed out for about 20 minutes and then came up to the sun room door to be let back into the house.

Mazie predicted an early spring! And the March and April data backed her up again!

mazie

Mazie on Housecat Day 2016. Photo by D. Sillman

March 2020 high and low temperatures were very close to average, but one-third of the days of the month had highs of 60 degrees F or greater! April 2020 also had average high and low temperatures very close to average but half of the days had highs that were 60 degrees F or higher and a number of these were over 70 degrees F! Also, there was no snow in either March or April! An early spring, indeed!

Mazie nailed it again! Her spring predictions have been correct 6 out of 8 times since 2013!

Take that, Phil (who is only right 40% of the time!)!!

Unfortunately, after a long and wonderful life, Mazie passed away just before we moved away from Pennsylvania. There was, then. no Housecat Day the first two years from our new home in Colorado. Last year, however, we corrected that situation!

pezz and pizo

Pezz and Pizo. Photo by D. Sillman

In December 2022, Deborah and I adopted two kittens, Pezz and Pizo. We got them from the  local Humane Society and they are sisters. Pezz is the smaller of the pair and has some of the quiet characteristics of Mazie. Pizo is a little bigger and a bit more athletic and has more of the aggressive attitude of Taz. Mostly, though, they are a bit of blend of the two extreme personalities.

On February 2, 2023, I took Pizo out the back door and put her down on the snow-covered patio. It was a sunny, cold afternoon, but she wandered all over the patio (even walking boldly across the snow!) and showed no intention of running back into the house. Pizo’s prediction: Spring is right around the corner!

Boy! Did Pizo get it wrong! As I wrote in my blog-email later in February:

“Friends and Family,

We’ve been watching a slow thaw after a “real” (according to the locals I have talked to) Colorado winter. My new snowblower has gotten a very good workout!

We have had a couple of weeks with days that climbed up over freezing in the afternoon, but it has been the intense sunshine that has melted most of the snow almost without consideration of temperature. Any place that is shaded still has deep, icy snow, and any place that gets both morning and afternoon sun is mostly clear. My front yard where my buffalo grass is planted has been slowly emerging from its snow cover. On a sunny day the snow pack recedes toward the south several feet, while on a cloudy day, even if it is above freezing, the snow line only moves a few inches. Any exposed concrete really heats up in the sun, and any snow or ice near the edge of the concrete melts.

pizo

Pizo on Housecat Day 2023

The nature of the snow has changed a great deal. When it initially fell, it was dry and powdery and had a bright, sparkly surface that reflected a bright glow of moon and yard lights. As it has been exposed to the sun, though, the snow has melted into a slushy mass during the day which then freezes solid in the deep cold of the night (most of our overnight lows have been in the single digits or colder!). The snow, then, has gone glacial on us. Just a few degrees colder and we would have an advancing ice front down the block!

My roof top solar panels were covered with snow and had stopped their production of electricity. Warning messages and alerts flowed in from my monitoring systems, but, when I called the engineer at the company that installed the panels, he said to just wait for the snow to melt. When a part of one of the panels got uncovered, it quickly heated up enough to melt the rest of the ice and snow covering the array. The system is now back on line!

Some of the streets in my neighborhood are snow and ice free, but others that are angled away from the direct sun are still heavily covered with ice and densely packed snow. There have been news reports from Denver (which has had even more snow than we have had this winter) that some neighborhood streets are still ice packed and nearly impassable. Denver, like Greeley, also has a policy of not plowing certain residential streets. One official told the local public radio that they were waiting for the sun to clear the roads!”

Maybe Pizo meant that it would be a wet winter and spring? We’ll see what happens this year!

Housecat Day 2024 is once again dedicated to Mazie, Taz, Binx and Bela. They will be greatly missed forever!

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Signs of Winter 7: Safflower Seeds!

sunflower(Click on the following link to listen to an audio version of this blog … Safflower Seeds

I went to the feed store a few Saturdays ago to pick up some bird seed. I have been buying shelled sunflower seeds since the end of October and have been impressed that 20 pounds of shelled sunflower seeds kept my feeder-organisms fed for about the same length of time as 40 pounds of still-in-the-shell sunflower seeds and only costs a few dollars more a bag! The time and work savings from not having to rake up the spent seed shells from under the feeder made those couple of dollars seem like a good bargain. Also, our granddaughter, Zofia, who is now 16 months old and extremely mobile, decided that the old sunflower seed shells looked like fun to play with (and stuff into her mouth)! We had to do something about that!

Anyway, Deborah and I were at the feed store with our 4-year-old grandson, Ari. Deborah and Ari were off in the back of the store looking for the store-cats (two, friendly, twenty-plus pound, American short-haired domestics!), and I was at the front looking over the stacked seed bags.

safflowerI picked up one bag that looked like the shelled sunflower seeds that I had been buying noting that the white seeds through the clear plastic of the bag looked larger than ones I had been scooping out into the feeder, I wasn’t wearing my reading glasses (big mistake) but the label on the bag definitely had a heading word that started with a capital “S.” I paid for the bag feeling pleased that it was about $8 cheaper than the bag I had bought 3 weeks ago. Some impact of supply and demand, I wondered? I watched Ari playing with one of the store cats, and I didn’t think any more about the bag of seed I was carrying.

It was only when I got the bag home that I clearly read its label: safflower seeds!

In my defense, the bag, except for the large label at the top, was identical to the shelled sunflower seed bags. They were both packaged by the same seed company and had phrases like “Wild birds love them!” and “No mess feeding” prominently splashed all over them.

What, I wondered, were safflower seeds? Time to fire up the Internet Search Engine of choice.

safflower

Safflower blooms. Photo by E. Ustua, Wikimedia Commons

Safflower (Carthamus tinctorius) is a plant native to Asia and Africa. It native range stretches from India over to the Middle East and up the Nile River into Ethiopia. It is a thistle-like, highly branched annual plant with attractive red, orange, yellow or white flowers from which dyes were once extracted. Safflower is one of humanity’s oldest cultivated plants. Archeological evidence indicates that it was widely grown in Mesopotamia in 2500 B.C. and also in ancient Egypt.

Safflower is sometimes called “the poor man’s saffron” because its dried flower petals resemble saffron and can be used to give saffron’s characteristic colors (although not its flavors) to foods (like rice). The Spanish brough safflower to Mexico during the 16th Century primarily to use it as a saffron substitute.

Safflower grows well in hot climates and is very tolerant of drought primarily because of its deep tap root. In North America it is widely grown in Mexico and California and is cultivated as a summer crop in the Northern Great Plains. Most of the harvested seeds from these safflower fields are processed for oil which is them used as cooking oils and to make salad dressings and margarines. Safflower oil is also used in the manufacturing of cosmetics, and, as we inadvertently found out at the feed store, it is also used as bird feed.

Kazakhstan leads the world in safflower seed production (in 2020 they harvested 226,739 tons of safflower seeds), Russia and the United States are second and third in the world for safflower production with just over and just under 90,000 tons of safflower seeds in 2020.

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Safflowers in a field. Photo by MGB CEE, Wikimedia Commons

Safflower flowers, seeds and oils have been used in traditional folk medicine throughout the Middle East (especially in Persia (Iran)) to treat a wide variety of maladies (including constipation, rheumatism, psoriasis and mouth ulcers). Scientific exploration of the efficacy of safflower products and extracts have indicated that they might be effective in treating heart disease, blood clots and certain kinds of cancer. Safflower also reduces blood sugar and cholesterol and helps to control skin inflammations. The chemical “hydroxysafflor yellow A” seems to be the active agent in many of safflower’s medical applications.

Safflower oil is also considered to be a very healthy cooking oil. It is a rich source of essential fatty acids and tolerates high cooking temperatures.

A number of seed companies extoll the efficacy of safflower seeds for use as bird feed. It has an excellent nutritional profile (38% fat, 16% protein and 34% carbohydrates) (compared, for example, to the average nutritional profile of sunflower seeds (28% fat, 15% protein and 22% carbohydrates). It does not have the heavy shells of sunflower seeds, but, instead each seed is encased in a thin, but tough protective layer. These safflower seed “shells” are shed by seed -eating birds but are so thin and fragile that they do not form a significant debris layer under an active feeder.

House finch at feeder. Photo by Rhododendrites, Wikimedia Commons

Safflower seeds are said to have a bitter flavor which many bird species tolerate or, at least, get used to. Feeder birds such as cardinals, blue jays, chickadees, nuthatches, grosbeaks, titmice, doves, house finches and house sparrows are all said to readily consume safflower seeds. Other bird species (like grackles and starlings) are described as intolerant of the safflower taste and will avoid feeders filled with safflower seed.

Another major selling point for use of safflower seeds in backyard bird feeders is the assertion that squirrels (which are the destructive banes of existence for many bird feeder managers) do not like the bitter flavor of safflower seeds, and will, therefore, not come to safflower seed bird feeders!

I filled my bird feeder with safflower seeds when I got home from the feed store Saturday afternoon. Through the rest of the afternoon only one bird (a red breasted nuthatch) came to the feeder, and he only stayed for a few seconds. My seed-eating fox squirrels, though, did come to the feeder and spent the afternoon gorging themselves on the safflower seeds. So much for a squirrel-proof bird feeder seed!

fox squirrel

Fox sqyuirrel. USFWS, Public Domain

Over the next four days the squirrels continued to eat the safflower seeds, but also spilled large quantities of the seeds out of the feeders. There was a small amount of the original sunflower seed feed in the feeder, and I think that they were sorting through the safflower seed trying to find it. They were also, though, eating a considerable amount of safflower seed. By Tuesday, flocks of house finches and house sparrows showed up at the feeder, and collared doves and juncos came in and gobbled up the spilled seed on the ground. I have seen chickadees in the feeder and several red breasted nuthatches. A blue jay also came in to the bird bath and dropped down to the ground seed for a few seconds. Most of the activity at the feeder, though, is squirrel!

So, squirrels like safflower seeds! They have recently finished off the seed pods from the backyard honey locust and would probably have eaten anything that I put out. The birds also eat the safflower seeds but do not seem to like them nearly as much as the sunflower seeds. My 20 pounds of mistakenly purchased safflower seeds should last three or four weeks. Then, I think, that I will go back to sunflower seeds to get everyone through the coming winter!

 

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Signs of Winter 6: Cats are Perfect!

pizo

Pizo. Photo by D. Sillman

(Click on the following link to listen to an audio version of this blog … Cats

“What greater gift than the love of a cat?” (Charles Dickens)

Purring is one of the most pleasant things a cat can do. As I write this, my cat, Pizo, is draped across my left arm and chest and is purring loudly. It is  cold day, and Pizo has a deep need to be warm. The conditions of our closeness more than satisfies her thermal needs, and her purring is lowering my blood pressure and stimulating the synthesis of all sorts of pleasant hormones and endorphins throughout my body.

Research has shown that cat owners who regularly hold their purring cats have a 40% reduced risk of heart attack and have measurable reductions in their blood pressures. Holding a purring cat can also ease migraine headaches, reduce anxiety and generate feelings of belonging. My twelve pound cat is making my writing difficult and slow, but it is a very fair trade!

Why do cats purr?

pezz

Pezz. Photo by D. Sillman

The simplest answer is that purring in a cat is like smiling in people or tail wagging in a dog. Often purring reflects contentment and happiness. Cats seldom purr when they are alone which suggests that purring is a mechanism of communication and, often, what is being communicated is happiness. A happy, contented cat typically stretches out, closes their eyes and sinks into deep, sustained purrs.

But cats also purr when they are afraid. The explanation for this from several behavioral scientists is that purring may be a way for a cat to both calm herself and also communicate a calming message to others around her or to the source of her distress or fear.

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Pizo. Photo by D. Sillman

Similarly, a cat might purr to relieve its own pain or discomfort. Purring is common in a mother cat as she is giving birth to her kittens. That purring continues after birth and attracts the blind, new-born kittens to the mom-cat to nurse. Kittens also begin to purr when they are only two days old. This purring is thought to be positive feedback for the mom-cat and also a mechanism of communications among the kittens themselves.

A cat will also purr when it is hungry. This is a very strong “feed me” message sent loud and clear to the cat’s human even when they are sitting at their computers trying to write.

How do cats purr?

An old hypothesis explaining how purring sounds are generated starts with nerve impulses coming into the larynx from the brain. These nerve impulses stimulate muscles in the larynx that then cause the cats vocal folds (aka “vocal cords”) to vibrate with each inhalation and exhalation thus creating the purring sound.

Mazie. Photo by D. Sillman

Some recent observations and experiments, though, on the physiology of purring reveals that there are no initial nerve impulses when purrs are generated, and there are no active muscular contractions in the larynx during purring. Instead the very low frequency sounds of a purr (the sound  is between 20 and 30Hz) seems to come less from the vibration of the cat’s relatively short vocal cords (which are seemingly too short to generate these low-frequency sounds in the first place) but, instead, from the vibrations of masses of fibrous tissue scattered across the vocal folds. When a cat relaxes the muscles supporting her vocal folds, these vocal “pads” are then free to vibrate as the air flow from inspiration and expiration blow across them.

Taz and friend. Photo by D. Sillman

All cat species can purr, but the large cats (lions, tigers, leopards and jaguars) very seldom do so. The females of these large cats (members of the subfamily Pantherinae) only purr when they are heat or when their cubs are nursing. What these large cats are able to do, though, that all other cat species cannot accomplish is roar! So, cougars, cheetahs, ocelots, servals, lynx, domesticated cats and the whole array of small, wild cats all can purr, but they cannot roar (a cougar’s blood-curdling call sounds more like a woman screaming (loudly!) than anything else in nature!

Photo by Benh-Lieu Song, Wikimedia Commons

So there is a relationship between purring and roaring, and one seems to prevent the other. The focus of this relationship is the vocal folds. In the non-Pantherinae cats the vocal folds are relatively short and arrayed in a characteristic triangular configuration. These short vocal folds cannot be vibrated energetically enough to generate a roar. In the Pantherinae, with the exception of the snow leopard, which is unable to roar, the vocal folds are quite long (and very well supported with strong connective tissues). They are also arrayed in a square configuration. These folds and their geometries and anatomies allow for the extremely energetic vibrations and the high volume sound generation of a roar. A lion’s roar can be heard up to five miles away! A roar is an incredibly powerful vocalization made possible by very specific laryngeal structures.

There was a recent article about cats in Scientific American (October 4, 2023) that discussed the remarkable anatomical and ecological similarities among all of the cat species on Earth. From domestic cats to tigers, all of these species basically look alike and do the same things in their ecosystems.  They are all “hard core predators” and carnivores. They are, to quote the Scientific American article, “not jacks-of-all-trades bur, instead, masters of one.” There are a number of species that have tried to take on the same predator roles as cats, but when they have had to compete against actual cats, those other species have always failed!

Mora. Photo by M. Hamilton

The skull of a house cat looks like the skull of a lion (although it is significantly smaller). The basic body shape, the teeth patterns (no molars behind the “slicing teeth” of the upper 4th premolar and the lower first molar) and the overall shape of their heads (all rounded, “baby-heads!” lacking the elongated face and jaw so common in other adult mammals) are all consistent among all of the cat species.

Cats have not changed significantly over evolutionary time. Their design and ecological role are perfectly matched. Why change when you are perfect? Or, to loop this ending back to the title of this blog, why change when you are “purr-fect?”

 

 

 

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Signs of Winter 5: Lichens!

lichen

Blue-gray rosette lichen and common sunburst lichen. Photo by R. Hodnett.Wikimedia Commons

(Click on the following link to listen to an audio version of this blog …. Lichens

Lichens have been described and discussed since the times of the ancient Greeks and Romans. Aristotle, Dioscorides, Theophrastus and Pliny all mentioned lichens in their writings and considered them to be an odd type of plant. Lichens were not of any great economic value or seemingly important at all, so they received very little attention or discussion.

Some of the earliest descriptions of lichens postulated that they were, in fact, merely excretions produced by rocks, or soil or trees, or that they were decomposition products oozing out of “higher” types of plants. The term “vegetable juice” was use to describe them. They were considered to have almost no complex structure at all.

rock lichen

Rocella tintoria, N. Nagel. Wikimedia Commons

A group of lichens that were valued for thousands of years, though, and which were described by Aristotle, are the rock lichens (Roccella tinctoria) from which a valuable purple dye was extracted. Other lichens of large or unusual conformations were also occasionally mentioned by observers and naturalists. But little detail about these species were developed. Some lichens that had shapes or colors that corresponded to the pseudo-scientific ideas called the “doctrine of similarities.” This doctrine contended that a plant that looked like a particular organ of the human body or in some way resembled physical aspects of some human disease would be of benefit to that organ or to curing that disease. So, a lichen that resembled a lung (Lobaria pulmanaria) was collected and used to treat lung diseases, and a lichen that has pustule-like eruptions all over it (Peltigera aphthosa) was used to treat thrush (a yeast infection of the mouth and/or throat). Similarly, a yellow lichen (Xanthoria parietina) was used to treat jaundice.

Starting in the 18th Century, lichens were almost universally considered to be some type of plant. They were variously classified as algae, as fungi (which then were considered to be a type of plant), as a liverwort or as a moss. Linnaeus in his 1751 work Philosophica Botanica mentions 86 lichen species. It was somewhere around this time, though, that Linnaeus disdainfully referred to lichens as the “poor trash” (“rustici pauperimi”) of vegetation. Over the next one hundred years, another 1000 lichen species would be described.

Caloplaca

Calopaca marina. R. Griffiths, Wikimedia Commons

In 1869 the Swiss botanist, Simon Schwendover, proposed that lichens were not plants and that they were also not the singular organism that they had previously been considered to be. He referred to lichens as “dual organisms” made of a fungus with algae living within the fungus’ cytoplasm. He used extensive metaphors to explain the relationship of fungi and the algae in the lichen. The algae, according to Schwendover, were variously “slaves” or kept “damsels” or “parasites with the wisdom of a statesman.” The fungi were, again according to Schwendover, “masters” or “tyrants” that kept and enslaved the algae inside of their cellular masses.

Schwendover inspired few converts to his lichen hypotheses. He was widely ridiculed and dismissed. His language made it difficult to seriously consider or accept his ideas, but even more fundamentally, his rejection of the increasingly popular, and distinctly Darwinian concept of “life divergence” (living organisms separating from each other as they live and evolve (Origin of Species had been published just ten years earlier, in 1859)) and his advocacy of an opposing concept of “life convergence” (living organisms fusing together), was, philosophically too extreme for many to tolerate. There were those, though, that set aside these prejudices and preconceptions and began to look at lichens more closely.

on rocks

Lichens on rocks at Dowdy Lake, Colorado. Photo by D. Sillman

In 1877, Albert Frank, a German botanist, coined the term “symbiosis” to describe the relationship between the fungus and the alga in a lichen. The idea of symbiosis was quickly expanded to cover a spectrum of interactions between species from parasitism to mutualism. The cooperative relationship of a lichen’s mutualistic symbionts (and other types of mutualistic pairs that were subsequently described) was a powerful counterpoint against some of the more extreme interpretations of Darwin’s Theory of Natural Selection. Huxley’s description of life as “a gladiator show where the strongest, the swiftest, and the cunningest live to fight another day,” and Spencer’s and Alfred, Lord Tennyson’s “nature red in tooth and claw” were tempered by the reality of “fitness” often meaning cooperation!

cross section

Lichen cross section. Photo by Nefronus. Wikimedia Commons

Lichens cover 8% of the Earth’s surface. This is a greater area than is currently covered by Tropical Rainforests. Lichens are the vital pioneering colonizers of newly exposed or emerging rock surfaces. The physical (via hyphal growth into micro-crevices in the rock)  and chemical (via acid production) breakdown of the rock generate the mineral matrix of soil. Lichens are the pioneers in almost all terrestrial successional sequences.

Lichens are an important part of desert crusts (see Signs of Summer 7, June 30, 2022). They can survive for long periods of time in dehydrated states (“suspended animation”). They can survive, to a degree, in space (although, the heat of re-entry is very tough on them!). Lichens are the principal food of arctic reindeer and other arctic grazers. Lichens are chemical factories that can synthesize more than a thousand chemicals not found in any other life forms.

Lichens first clearly show up in the fossil record about 400 million years ago. Lichens, according to DNA analysis, have evolved independently 9 to 12 times! Fungi and algae will spontaneously fuse together to make either a lichen or a fairly undifferentiated fungal/algal mass. The functional assemblage of the lichen symbionts occurs if each participant brings some physiological or structural features to the composite organism (often referred to as a “holobiont”) that facilitates the survival of mutualistic pair.

lichen diagram

Lichen symbiosis. Photo by M. Grimm, Frontiers

Recent research has explored the nucleic acid composition of lichens. In addition to the DNA of the fungal and of the algal mutualists, these studies have revealed DNA from a myriad of bacteria and yeasts (which are single-celled fungi). The picture of a lichen, then, is more complex that we had assumed. It is not just a mutualistic symbiosis between a fungus and an alga, it is an entire micro-ecosystem of organisms! As one researcher put it, “lichens don’t have a microbiome, they ARE a microbiome!

So, what is an individual? Lichens are obviously not individuals: they are mini-ecosystems! But what about people? In an “individual” human there are, according to the most recent estimates, about 30 trillion “human” cells. In addition to those human cells, though, there are also estimated to be 39 trillion bacteria living in the internal and external microbiomes of the body. Add to this numbers maybe 4 trillion fungi (1% of bacteria microbiome), and you have a complex, diversly populated system.

So what is an individual?

An interesting aside: in a paper recently published in Nature, researchers state that a major factor causing a person to experience sustained SARS-CoV2 infections (i.e. “long COVID) is an imbalance in the fungal microbiome of the intestines. We are a multitude!

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Signs of Winter 4: Truffles!

truffle

Black truffle, Public Domain

(Click on the following link to listen to an audio version of this blog …. Truffles

Truffles are very famous fungi. They are packed with complex chemicals that give some of them deep, musky, earthy flavors which they contribute to food even when added in very small quantities. Since truffles sell for astronomical prices (white truffles often cost $4000 a pound and black truffles cost $300 to $800 a pound), careful to outright stingy use of them in cooking seems extremely logical.

“Truffle” is both the common name of a diverse group of subterranean fungi and also the name of their edible fruiting bodies. Many truffle species, like the white and black truffles mentioned above, are in genus Tuber, but there are over a hundred other genera of fungi that have species that are called “truffles.” All truffles exhibit the fungal tendency to synthesize a diverse array of chemicals, and they make these chemicals in very large quantities. When you dig up a truffle, the scent of its chemical array can be overwhelming! A truffle loses its scent very rapidly after it is dug up and detached from its supportive mycelia. It must, therefore, be transported to market and used as quickly as possible after harvesting.

Some of the truffle chemical arrays are pleasing to human tastes and olfactory perceptions (like the deep flavors of the white and black truffle). Other truffles generate less pleasant but equally intense aromatic chemical arrays. Some of these other “truffle-scents” have been described as resembling sewage gases or baby diarrhea. Not something that would fit in haute cuisine!

truffle

Truffle in ground. Photo E. Johnson, Cambrideg Univeristy

All fungal species labeled as “truffles” are mycorrhizal fungi that form associations with the roots of trees or shrubs. These fungal mycorrhiza are ectomycorrhiza and, so, grow on the outside of a root with a mantle of connecting material holding the mass of the surrounding hyphae and the root together. Many different tree species have associated truffle mycorrhiza. Notably oaks, beeches, birches, hazels, pines and poplars form mycorrhizal associations with the most edible and commercially valuable truffle fungi.

The life cycle of a truffle is complex and full of potential failure points. The truffle fungi, apparently, are not very robust and are easily ousted from their ectomycorrhizal positions on the tree and shrub roots by other, more aggressive fungal species. Also, it takes many years for truffle fungi to grow large enough to begin to form fruiting bodies. Any diseases of or damage to the supportive tree or shrub during this period of time can short-circuit the formation of the fruiting bodies.

There is also a suggestion that the truffle fungus needs to have very specific soil bacteria associated with it in order to synthesize the full array of aromatic chemicals! Truffles, then, like grapes take on many of their subtle (and highly valued) flavors only when grown in certain soils. This truffle “terroir” can make huge differences in the market price of the harvested truffles!

Lucy

Lucy, a trufle hunting dog. Phto by E. Johnson, Cambridge University

The final life cycle problem of  truffle fungus is how to get the spores in its subterranean fruiting body to be dispersed out through its surrounding environment. This dispersal is via frugivorous animals. The fruiting body needs to be eaten by a squirrel, vole, gopher, chipmunk, deer or bird, and the spores must then pass through the animal’s digestive tract and, thus, get spread about the environment in the animal’s feces. In order to be noticed by these animals, the fruiting body emits its complex mix of volatile odor chemicals!

Because of the complexity of the environmental needs of the truffle fungus, truffles have historically been harvested from natural, forested habitats where all of the complexities of truffle biology are handled by natural, ecological processes. Roving truffle hunters hike through pristine woodlands, following their trained scent animals (usually dogs or pigs) (both dogs and pigs have exquisitely sensitive noses and can be easily trained to find truffles) to the scattered locations of truffle development. The hunters can dig up thousands of dollars-worth of truffles each day! This scenario is acted out in France, in Italy and in the United States each year as the wild truffles mature. The truffle hunter and their dogs or pigs dig out the hidden truffles (they are usually a few inches to a foot below the soil surface) and it is often a battle between hunter and his dog (or pig) to unearth and bag up the truffle without the scent animal eating them first! Interestingly, truffle hunting pigs are no longer allowed in Italy because of the extensive damage they do to the truffle mycelia when they dig out the truffles. Pigs are also very hard to control when they smell a truffle!

Truffle scent animals vigorously seek out the hidden fruiting bodies. One truffle dog owner  remarked that his dog, Dante, acted as though “he sensed god living just below the surface of the soil” and rapturously sought to unearth him! One difficulty truffle scent animal handlers have is rewarding their animals for finding the truffles. A bit of liver is no substitute for a mouthful of truffle!

Natural habitats suitable for wild truffles have been declining over the past century. Changes in agricultural practices, changes in land use and changes in life styles have all contributed to declines of truffle-friendly, pristine woodlands. There has been a concerted effort, then, to translate the truffle-supportive woodland ecosystem into managed, cultivated plantations.

farm

Truffle farm in France. Photo P. Sourzet, Scielo

Beginning in the late 1960’s and 1970’s, truffle plantations began to successfully grow truffles, and by the 1980’s these plantations had been established in many countries around the world. About 80% of the truffles produce in France are now grown on plantations. Establishment of these plantations is a difficult, delicate process requiring precise analysis of soils, healthy tree species and control of potentially competing fungal species. Also, the truffle plantations must be secured by strong fences to keep out wild animals (like wild boars!) who are attracted to the compelling scent of the maturing truffles.

The time it takes to establish a truffle plantation and the cost to manage and protect it, make truffle farming a very expensive and risky business. The potential yield and incredible payoff, though, make this risk worth taking.

There was a recent article in the New York Times (November 11, 2023) describing a declining crop of wild truffles in Italy. The dry summer and fall of the past few years (all attributed to climate change) have stressed the trees that symbiotically support the truffle fungi causing a precipitous decline in truffle fruiting bodies. The continued decline in these vital tree species could lead to the extinction of the wild truffle. A catastrophe of unspeakable proportions!

(Next week: lichens!)

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