Saturday, December 3, 2016
Note: This program first aired on December 3, 2016.
If you wanted to design an ocean animal that is perfectly constructed to get hit by ships, what characteristics would you include? It should probably be big, and slow moving. Make it dark so it is hard to see. If it is a mammal, it will need to spend time at the surface, so it can breath. It should have to spend long amounts of time feeding on very small food items, again, often at the surface, at night. Make it easily stressed by noise, which decreases its ability to communicate with others of its kind. Put its range right near shore, in major shipping lanes near highly populated areas.
This isn’t just a hypothetical exercise, this animal actually exists. It is called the Eubalaena glacialis, North Atlantic Right Whale, and it is one of the most endangered large whales in the world.
Many people have heard the story of the Right Whale, so called because they were the “right” whale to hunt especially in the early days of whaling. As a species evolved to feed in relatively shallow productive water of the continental shelf, they stay close to shore, which made them accessible to land based hunters in small boats. They could be brought to shore and processed on land, and were an important part of the land based whaling industry, before the more ocean going sperm whale was discovered and chased all over the global ocean on multi year whaling expeditions. Right whales also have enough blubber, or body fat, to lower their overall density enough that they will float when killed, again, making them easier to manage from a small boat. It is hard to know how many Right Whales were around before commercial whaling began, but they received internationally recognized protection starting in 1935, after having been harvested consistently in the northwest Atlantic since the 1500’s, and most likely earlier in European waters. Researchers estimate that there were less than 100 North Atlantic Right whales left in the western Atlantic in 1935. Since that time the population has rebounded, but very very slowly. The most current published population estimate puts the number around 476 individuals, based on direct observation. Though they are no longer hunted, they are still highly endangered.
Why are they still endangered? If we return to our list of characteristics of our vulnerable ocean animal, we can start to see why. They like to hang out where we spend most of our time in the ocean too. They fish where we fish. They travel where we travel. The two big reasons that Right whales die as a result of human activity are 1. They get tangled in fishing gear and 2. They get struck by ships.
The fishing gear entanglement issue is complicated, and unfortunately seems to be a fact of life for North Atlantic Right Whales. Researchers have observed that 83% of these whales have scarring consistent with entanglement, and around half show signs of multiple entanglements. Changes to fishing gear are a start at preventing this problem, but there is further work to do.
On the ship strike side, and because I work at a maritime college I focus more on this end of things, some very positive strides have been taken. In areas where these whales are known to congregate at certain times of the year, speed limits have been imposed for vessels over 65 feet. These zones are called seasonal management areas or SMAs and came into effect in 2008. Compliance on the part of industry has slowly but surely increased since that time. Speed makes a huge difference. If a whale is struck by a ship traveling at 20 knots, mortality is 100%. When ship speed is reduced to 9 knots, mortality is around 20%. And it has had an impact. Before 2008, 87% of the ship strike mortality occurred within or just outside the SMAs, because that is where most of the whales were. Since these slow zones were established, all of the documented ship strike mortality events, averaging 1 per year, occurred outside of the SMAs. So just getting ships to slow down where the concentration of whales is highest has worked to decrease our impact on this population. Not that we should stop and pat ourselves on the back, there is certainly more to do. These whales continue to face the threats of ship strike outside of the SMAs, entanglement in fishing gear, increased stress from noise pollution, and the likelihood of a genetic bottle neck stemming from such low population numbers in the early 20th century. We’ll learn more about what is being done on a future show.
There is a ton of info out there on these whales, including many federal websites, due to the federal regulations stemming from the protections encumbered by the Endangered Species Act.
The study that documented the positive impact of the speed reduction zones: http://www.int-res.com/articles/esr_oa/n023p133.pdf
From the federal government: http://www.nefsc.noaa.gov/publications/tm/tm219/8_NARW.pdf
Saturday, November 19, 2016
Note: This program first aired November 19, 2016.
I know many of you listen to this show because you like hearing about the natural world, learning things you didn’t know before, and getting insights into the amazing mysteries of nature. I know this show, and this radio station as a whole can serve as a respite from the 24 hour news cycle, the information overload and the go go go culture we are awash in, even here in eastern Maine. And I know that after the last two weeks we’ve had, I should be offering you a show about kittens and puppies, just to provide something distracting, hopeful, sweet and kind.
I think you know what is coming. I can’t do that. Not yet anyway. I’m in the camp with the majority of those casting votes in the last election who are not happy with the results of the election. There are so many reasons, but one especially relevant to this show is the appointment of Myron Ebel to lead the Trump administration’s transition at the Environmental Protection Agency, an appointment that many presume will lead to Ebel’s nomination to lead that agency after the transition of power.
Ebel is a known and vocal climate skeptic who directs policy on energy and the environment at the Competitive Enterprise Institute, a think tank that both the New York Times and the National Review characterize as libertarian. While he says that he believes human caused climate change is real, he follows that up with the belief that it isn’t really a big deal, and certainly not something we need to worry about or more importantly, spend any money on right now. The main targets of his derision are the models and forecasts developed and constantly honed by climate scientists, in an attempt to predict the near climate future. And I quote:
*“… the scientific consensus is not based on known scientific facts. It is based on discredited climate model projections, such as the ones promoted by Gavin Schmidt at NASA’s Goddard Institute for Space Studies, and fantasy reconstructions of past climate history, such as the infamous hockey stick.”*
Climate models to have a degree of uncertainty, and scientists work tirelessly to revise the models, using “back casting” as a way to test them (can they run and accurately predict the climate trends we have already experienced? If so, than then you can have a relatively high degree of confidence in the model, within the strict limits of what it is designed to test). The International Panel on Climate Change reports take great pains to report confidence intervals with each of their predictions and prioritizations of climate related problems. So while Ebel seems to delight in denigrating what he calls unfounded climate alarmists, many of the forecasts he is critical of are coming with acknowledgements of the uncertainty.
Ebel’s think tank’s most recent policy position promotes anti regulation legislation, and that seems to be at the heart of this issue. Lowering the regulatory threshold is one of the main pillars of the Ebel’s career, and with climate change, the easiest way to do that is to deny the problem that the regulations are supposed to be addressing. If climate change isn’t really a problem, of course there is no need for the Clean Power Act, or the Paris Climate Treaty. It seems that the answer to when was America Great in the first place is the time before industry faced any kind of regulation. Annoying regulations like the Clean Air Act, and the Clean Water Act.
So for all the reasons to be concerned about the ramifications of the recent election, and there are many, incredibly serious ramifications, this one might be the most important. Climate change doesn’t just screw it up for us in America, it screws it up for everyone on this planet.
Administrator of the Environmental Protection Agency isn’t technically a cabinet level position, but it is high enough in the ranks to require Senate approval. We’ll get back to the trees and fungus and forests, plankton and algae and whales, the plants that run our lives, the winds that bring the weather and yes the kittens and puppies make us smile in the coming weeks. But in the mean time, call your senators. Tell them how you feel about someone who doesn’t take climate change seriously leading the agency tasked with protecting the environment we all share and depend on.
Senator Angus King: Augusta Office: 207 622 8292, Scarborough office: 207 883 1588 https://www.king.senate.gov/contact
Senator Susan Collins: Augusta Office: 207 622 8414, Bangor office: 207 945 0417 https://www.collins.senate.gov/contact
The New York Times profile of Ebel: http://www.nytimes.com/2016/11/12/science/myron-ebell-trump-epa.html?_r=0
The Competitive Enterprise Institute, where Ebel is Director of the energy and the environment policy division https://cei.org/
The Cooler Heads Coalition, a group of climate skeptics and deniers Ebel leads http://www.globalwarming.org/about/
*Source of the quote from the show: Myron Ebel’s blog post about a New York Times article attacking the climate scientist Willie Soon: http://www.globalwarming.org/2015/02/27/new-york-times-repeats-scurrilous-greenpeace-attack-on-willie-soon-without-checking-the-facts/#more-23224
The Clean Power Plan https://www.epa.gov/cleanpowerplan/clean-power-plan-existing-power-plants
Where he said that he thinks anthropogenic climate change is real, but that its not a big deal: http://web.archive.org/web/20161111000552/http://www.eenews.net/stories/1060041292
Really, here it is: http://www.nasa.gov/feature/goddard/2016/climate-trends-continue-to-break-records/
Saturday, November 5, 2016
Note: This program first aired November 5, 2016.
Food anchors us to the land(*), it places us in a landscape and timescape. Food also anchors us in our community. We share a common language with those who eat the same things we do, and food gives us a currency with which to exchange culture with people with different traditions.
I never feel more human than I do when I am eating wild foods. Whether it is incorporating a daily morning berry foraging walk that provides my summer breakfast, harvesting and tincturing a medicinal herb to support a loved one’s health, stumbling on an edible fungus in the fall or collecting favorite algae at the sea shore, nourishing myself from uncultivated yet bountiful sources feeds something as old as time in me.
I don’t as of yet hunt animals, so the wild food gathering I undertake is primarily focused on plants. With this in mind I signed up for a class with Arthur Haines, a well respected botanist here in New England and passionate and generous advocate for the wild food and rewilding movement. Our topic was acorns, how to collect, preserve, process and enjoy this at times prolific nut.
I was delighted to hear Arthur sing the praises of the Northern Red Oak acorn (Quercus rubra), a member of the Black Oak subfamily that includes Scarlet Oak, Pin Oak and many others. I live in a Red Oak forest, the acorns literally drop onto my door step in the fall. Northern Red Oak acorns are distinguished by their nutritional profile, they are nearly 50% lipid (or fat). Crack open a fresh Red Oak acorn and you will feel the oiliness on your fingers. That fat is mainly oleic acid, the same monounsaturated fatty acid that is found in olive oil. The rest of the bulk of the nut is complex carbohydrate, and a small percentage of protein.
The process of using acorns for food begins with gathering and sorting. It turns out not all acorns are created equal. Some are damaged right from the start, fail to develop to full size and are shed by the tree early. Others look like regular acorns, but when hefted in the hand reveal a lighter than average weight. They weigh less because they are hollow, or are in the process of becoming hollow. They are hollow because they are being eaten from the inside out by the larva of the acorn weevil, a small beetle that lays its eggs in the developing acorn. As the acorn approaches maturity, the egg hatches and the tiny larva, now housed inside its own food source, begins to eat. As it eats, it also respires, and just like we exhale carbon dioxide and water, so does the larva. That gas has mass and dissipates through the acorn shell, so as the larva eats the acorn, the acorn gets lighter and lighter. Once the larva has eaten all of the goodness inside, it exits the acorn through a little hole it creates---thus any acorn you find with a tiny circular hole in the side is no good—it is just full of acorn frass. Any acorn you find without the tell tale exit hole, that feels feather light, much lighter than all the others in your hand-if you cracked that one open it is likely you would find a number of acorn weevil larvae still munching away inside.
We can’t just shell an acorn and pop it into our mouths, and this is something aboriginal populations world wide figured out thousands of years ago. Acorns contain tannins, a group of chemicals that yield both a bitter taste and an astringent feel in the mouth. Primarily thought of as a defensive compound for the plant, some tannins have anti nutrient properties, while others (like the ones in tea) have strong nutritionally beneficial anti oxidant properties. The tannins in acorns are of the former variety, and make them in their unprocessed state, an unpleasant eating experience.
The processing may be one reason these native nuts have fallen out of favor, after drying, cracking and shelling, you still have to chop or grind them and then leach out the tannins. The process, though not intensive throughout, takes weeks. The result at the end though is a relatively bland flour, with a high healthy lipid content, and a very low glycemic index, suitable to mixing in with other flours in baked goods, or eating as a hot cereal with maple syrup. If you like getting connected with your food source, aren’t afraid a little work and are up for a culinary adventure, this would be a good year to try eating acorns. For many of us in eastern Maine, they are falling on our doorsteps.
On acorn weevils from Iowa State Extension service: http://www.extension.iastate.edu/news/2007/sep/072107.htm
Encouragement from the Earth Island Journal for eating acorns at Thanksgiving: http://www.earthisland.org/journal/index.php/elist/eListRead/this_thanksgiving_consider_cooking_with_acorn_flour/
Delta Institute of Natural History (and website of Arthur Haines, the botanist and wild food advocate mentioned in the program): http://www.arthurhaines.com/ *The first line of this show (about food anchoring us to the land, comes from Arthur’s description of the acorn workshop)
There are lots of references online for how to process acorns, some using hot water to leach the tannins, others using cold. Some crack the nuts immediately, others dry the acorns first (they are A LOT easier to shell if dry, and can be stored dry in the shell for years). The work shop I attended emphasized making the process efficient, but regardless—go ahead and experiment! There’s lots of info out there to get you started!
Saturday, October 22, 2016
Note: This program first aired on October 22, 2016.
Earlier this fall, a listener contacted me suggesting a topic for the show. He had just replaced his glass hummingbird feeder with a polycarbonate plastic one, in a successful attempt to thwart the yellow jackets that were frequenting the feeder. He wondered though, about the possible contaminants, especially BPA, that the birds might be exposed to. Anticipating the arrival of the ruby throated humming birds in the spring and watching them feed in our yards all summer long rank high among summer pleasures for many Mainers. But with growing awareness that problematic plastic additives show up anywhere, and everywhere, it has been only a matter of time until some one put two and two together and asked this question.
Plastics are polymers, chains of individual units (monomers) strung together chemically. Most plastics are a mix of different kinds of hydrocarbons, with various additives to give them specific physical attributes. These additives have various levels of fidelity to the plastic they are part of, and some readily leach out of the plastic into the environment. Awareness has grown in the past 10 years of this potential problem with the consumer goods and food packaging we contact on a daily basis.
Some chemical additives may be inert, other are quite biologically active and that is the crux of the problem. Bisphenol A, or BPA, the additive my listener asked about, is used in polycarbonate plastic, the kind that lexan water bottles, protective eye wear and DVDs are made of. It has proven itself to be, as many plastic additives are, a potent estrogen mimic, meaning, it binds to the same receptive sites in cells that naturally occurring endogenous estrogen does.
Estrogen is the female sex hormone in all vertebrates, from fish to mammals. It plays the same role throughout the vertebrate group, in carefully timed pulses it guides the development of the reproductive system. The biological or anatomical sex of an individual is the result of the relative balance of estrogen and male sex hormones like testosterone, and the timing of the exposure of cells to these hormones. Through the study of developmental biology, we’ve learned that the critical period for this exposure is very early in embryonic development.
Having an environmental estrogen out there can mess up this system, throwing off the balance of hormones, and the timing of exposure. And that is where most of the permanent impact of chemicals like BPA lies, by mimicking estrogen and flooding estrogen receptors in the cells of vertebrate embryos BPA can interfere with the normal development of the reproductive system of exposed organisms, be they fat head minnows, Japanese quail, or human beings.
Most of the research on the impacts BPA on wildlife has been on freshwater aquatic vertebrates, as it is easy for BPA to get into surface water through municipal water treatment facilities and industrial run off. The research on birds is much more limited, but that which is out there points to embryonic exposure leading to persistent malformations of oviducts and the shell gland (leading to thin and weak shells) in female birds, and changes to brain development in male birds leading to reduced copulatory behavior. These are problems, that, while initiated when the birds were embryos, don’t show up until they reach sexual maturity.
All of this bird research has been on model organisms like Japanese quail or domestic chickens, using exposure vectors like injecting BPA directly into eggs, or dipping eggs in an aqueous solution containing BPA. No one has looked at BPA’s effect on wild birds like humming birds, exposed through the parent’s ingestion of BPA laden sugar water from your new plastic hummingbird feeder. All we can say is that there is a demonstrated estrogenic effect in some birds in experimental conditions, but that the impacts on wild populations with more natural exposure are unknown. If there were negative effects to hummingbirds, I would expect them to be reproductive.
And before you all start writing me telling me that you can get BPA free polycarbonate and other plastics, yes, you can. It turns out that many of the chemicals used to replace BPA are simply other bisphenol chemicals, or are less well studied, and when they are investigated, turn out to have similar biological actions. So just because it says BPA free, doesn’t mean it is necessarily great.
If you are worried about the reproductive health of the hummingbirds who visit your yard, you may want to continue your search for the perfect glass feeder, or better yet, cultivate the original hummingbird feeder, a yard full of flowers.
Excellent review article in Dose Response, focusing on aquatic vertebrates https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4674185/
Full text of a Swedish PHd dissertation from the University of Uppsala on environmental endocrine disruption in birds: https://uu.diva-portal.org/smash/get/diva2:165990/FULLTEXT01.pdf
Environmental Defense Fund on BPA free: https://www.edf.org/health/three-reasons-bpa-free-wont-protect-you?utm_source=ggad&utm_medium=cpc&utm_campaign=gr-bpafree&gclid=COXaxd316c8CFQkkhgodBkkBtg
Other sources on BPA alternatives: http://www.the-scientist.com/?articles.view/articleNo/45789/title/Effects-of-BPA-Substitutes/
And from UCLA http://newsroom.ucla.edu/releases/chemical-used-to-replace-bpa-in-plastic-accelerates-embryonic-development-disrupts-reproductive-system
Saturday, October 1, 2016
Note: This program first aired on October 1, 2106.
I was asked by a listener recently about the place of mosquitos in the world. The combination of news stories about the Zika virus and developing a vaccine on the one hand, and rampant species extinction on the other got him wondering—why don’t we solve the Zika problem by trying to extinct the mosquito? At least that would be an extinction that solves a human problem. If things are going extinct anyway, why not try to get some benefit from that? The real question here is: are mosquitos good for anything?
And the answer is of course, it depends on who you ask. The typical answer to this oft asked question (why can’t we just kill all the mosquitos) is that they provide critical ecosystem services, in the form of being food for other animals in various ecosystems. Scientists are not unified on the impact of eliminating mosquitos (of which there are over 3500 known species, only a couple of hundred of which bite humans). Many say that the positive public health benefits far out weigh any temporary ecological disruption, and that any unoccupied former mosquito niche would be filled immediately by another organism. There are varying opinions and findings about the true role of adult or larval mosquitos in various food webs; they have been on the scene for over 100 million years, allowing plenty of time for elaborate co-evolution with predators, yet food web studies often demonstrate that mosquitos do not make up a large percentage of the food items in the stomachs of insectivorous predators. Male mosquitos do not bite, and feed on the nectar of flowers, and thus serve a pollination role, though none of the plants typically serviced by them are of any economic importance to humans. So the summary on this commonly held wisdom is maybe, perhaps there would be some impact to various ecosystems, and some specialized predators would go extinct, but nothing that we know as of now that would negatively impact humans.
On the other side of this question asks why would we kill all the mosquitos, if we could? Mosquitos are flies, in the order Diptera, a group of insects with mouthparts specialized for piercing and sucking. Their life history requires a blood meal for development of the eggs, hence only the females bite. It is this biting habit that makes them an annoyance, a public health problem and an excellent means of transportation, again, depending on who you ask. Many of the diseases that affect millions of people throughout the world, particularly the economically developing, tropical and sub tropical world, are spread by mosquitos. Malaria, dengue fever, west nile virus, triple E, chikungunya virus, yellow fever, a host of encephalitises, zika, all these are spread either from human to human, or from zoonotic (or animal) host to human, through mosquito bites.
The problem is that mosquitos exploit an ecological niche that includes us warm blooded nutritious humans, and are at the same time exploited by pathogens that use mosquitos to transport them around. Mosquitos are really just a proxy species for the pathogens we would like to rid the world of. A patsy. Purposeful extinction of mosquitos would be an attempt to extinct the pathogens that we would like to avoid. It is these pathogens that kill hundreds of thousands of people, mostly children a year, and sicken millions more. To return to that original question, are mosquitos good for anything—if you were to ask a malaria plasmodium, or a west nile viron, the answer would be a resounding yes.
It was John Muir who once said “When we try to pick out anything by itself, we find it hitched to everything else in the Universe.” * And Aldo Leopold said “To keep every cog and wheel is the first precaution of intelligent tinkering.” ** This classical American environmental thinking argues strongly against taking out an entire family of organisms, it's flipside is the same logic that hunted large predators to near extinction throughout North America. But I doubt the Muir and Leopold were thinking about malaria, and deep human suffering.
I think what my listener wanted to know is if we did succeed in taking out all mosquitos, would it initiate some kind of ecological collapse? Are mosquitos a keystone species? The answer is potentially no, especially when colored with the anticipated reduction in human suffering. With that card on the table it may be difficult to get a truly unbiased assessment. Which is doesn’t even take into account if purposeful extinction would be possible, though people are working hard on this front all the time.
I’d like to see us use our ingenuity to find a way to prevent contact between the disease spreading mosquitos and humans, rather than pursue what are likely to be toxic extermination methods. I think we can go a lot further to reduce human suffering and eliminate, what one scientist called, collateral damage. These are difficult philosophical questions—I appreciate you asking them. Keep them coming.
I include this for the table of mosquito borne diseases part what down the page: https://en.wikipedia.org/wiki/Mosquito-borne_disease
The journal Nature has addressed this very same question: http://www.nature.com/news/2010/100721/full/466432a.html
*From My First Summer in the Sierra
**From Round River: From the Journals of Aldo Leopold
Saturday, September 17, 2016
Note: This program first aired September 17, 2016.
Our bodies are over 60% percent water. We can only live a matter of days without water. Water covers 71% of the surface of this planet.
It should be no surprise that people attempting to live according to traditional, earth centered, non western value systems hold water to be sacred. Call them Indians, native peoples, first nation, aboriginal, tribal, many of these communities still hold to ideals that see water as the sacred blood of the earth, as the first medicine. And so it should be—all life depends on access to clean water.
Water is a polar molecule, making it a wonderful solvent, readily dissolving any substance that has an atomic electrical charge. Liquid water is fluid, and can easily transport any other fluid substance in it, even if that substance is non polar, having no electrical charge, and can’t dissolve in the water. Even if that substance is crude oil.
Crude oil is made up of a mixture of many different fractions of hydrocarbons, ranging from the heavy end with things like asphalt and paraffin, to the light end with things like the methane and propane, some of the constituents of natural gas. Crude oil contains other substances, related to the hydrocarbons we burn in our cars and furnaces, things you might have experimented with in organic chemistry class, like the aromatics benzene, toluene, and xylene. And even though the aromatics come from crude oil, something we typically think of as insoluble in water, these light fractions are soluble in water. They also have a low atomic weight, so they evaporate into the air quite readily as well. And worst of all, they are carcinogenic.
This is the kind of thing you think about when you learn that an oil transporting pipeline is about to be built through a river that is your source of drinking water. You think about the pipeline leaking, and the heavy fraction of the crude oil, being denser than freshwater, sinking to the bottom of the river, virtually impossible to clean up, and the lighter more soluble fractions traveling with the water to be taken up by municipal water systems down stream. You think about how common it is for pipelines to break, and in isolated rural areas how long it takes for people to notice.
These are the things I was thinking about as I stood in the rain attending a solidarity event for the Standing Rock Sioux tribe in North Dakota. The Standing Rock tribe has been protesting the fast track approval of the Dakota Access pipeline, its permitted path through off reservation sacred sites, and its crossing of the Missouri River, the drinking water source for the tribe and rural farmers and ranchers downstream. Native tribes from all over north America have been converging on the protest encampment at the Sioux reservation in a show of solidarity, and events like the one I attended, organized by Wabenaki leaders here in Maine, are popping up nationwide. You don’t have to be Native American to understand that water is sacred, though watching the Wabenaki prayer ceremonies made me realize that I lost the language of sacred connection many generations ago. Nor do you have to be a scientist to understand the linkage of water pollution and illness, and unfortunately I speak that language all too fluently.
Water is not unique in the universe, in fact the only reason we have it hear on Earth is that it came here the same way all the other matter on Earth did, as an aggregation of space dust and rocks. But water is what makes this planet unique, and what makes life possible on this third rock from the sun. The Standing Rock Sioux know it, and so do you.
Yep, pipelines do leak into rivers: https://usresponserestoration.wordpress.com/2014/06/20/as-oil-sands-production-rises-what-should-we-expect-at-diluted-bitumen-dilbit-spills/
People say these pipelines don’t leak. Really? http://www.npr.org/sections/thetwo-way/2016/07/25/487357502/canadian-oil-spill-threatens-drinking-water
Another one: http://news.nationalgeographic.com/news/energy/2015/01/150120-oil-spills-into-yellowstone-river/
A map of the pipelines: https://www.propublica.org/article/pipelines-explained-how-safe-are-americas-2.5-million-miles-of-pipelines
Saturday, September 3, 2016
Note: This program first aired on September 3, 2016.
Last week we talked about fungus, and they ways it makes a living in this world. The mushrooms we see in the forest are just the tip of the fungal iceberg, the vast majority of fungal biomass in the forest is subterranean. These are the bundles of fungal fiber called mycelium, and if the mushroom’s job is reproduction of the fungus, the mycelium’s job is to nourish it.
There are three ways that fungi can get food from the environment; they can parasitize another fungus*, they can decay organic matter, or it can form a relationship with a plant in an “I’ll scratch your back if you scratch mine” symbiosis called mutalism. We covered parasitism and saprotrophism earlier, leaving mutalism for today.
It turns out that many of those mushrooms you see erupting from the forest floor are from fungal biomass that is in direct relationship with the trees that make up that forest. The individual hyphal filaments that make up the mycelium, or all that fungal biomass beneath the surface of the soil, get up close and personal with the tiny root hairs, or rootlets from the tree and form what is called a mycorrhizal relationship, “myco” referring to fungus, and “rrhizal” referring to roots. Trees and their fungus typically form what is called an ectomycorrhizal relationship—meaning the fungus only just barely infiltrates the upper layers of the rootlet tissue, squeezing in between the cells of the root outer cortex, forming a sheath. The conjoining of the tree roots with the fungal mycelium effectively expands the tree’s root system by orders of magnitude, and even directly connects it to other trees of its species if the mycelium forms an ectomycorrhizal relationship with more than one individual.
Typically a fungal species has only one suitable tree species it can pair with, though often trees can have many different fungal partners. Many of the trees I see daily are obligated to form relationships with fungal partners; they cannot grow without the assistance of the fungus. Those groups include pines, oak, beech and spruce. Other tree species are facultative, and can grow without a fungal partner but grow better with one. Examples include maples, juniper, willows and elms.
I said this is an I’ll scratch your back if you scratch mine kind of situation, both partners benefit from this trans species contact. As I noted, the tree gets a major extension of its root system, gaining what one source called “hundreds of thousands of kilometers’ of individual hyphae, collecting water and inorganic nutrients from the soil. Essential nutrients like phosphorous and nitrogen are limited in the terrestrial environment, and the fungus is able to aggregate these and make them more available to the tree than they would be otherwise. The fungus also is able to collect water from the soil, though there can also be instances when the plant gives moisture to the fungus as well. And in some cases the fungus produces plant growth hormones, stimulating tree root growth. What we know for sure the fungus gets out of the relationship is carbon, in the form of sugar. 10 to 15 % of the carbon fixed by the tree gets channeled to the mycorrhizal partner. Both players are able to trade something they are good at getting from the environment for something they need, to the benefit of everyone.
This kind of relationship isn’t limited to trees and mushrooms. Many herbaceous plants and agricultural crops form mycorrhizal relationships as well, relationships characterized by even deeper infiltration of the fungus into the plant tissue. And in a totally different part of the world, coral reefs, we see the mutualistic symbiosis of coral polyps and photosynthetic plankton, swapping carbon in the form of sugar in return for inorganic nutrients. In a great example of convergent evolution, many realms of life species have evolved to swap resources in order to increase their competitive fitness. That is the cool thing about evolution, when something works, it keeps popping up independently on the tree of life.
So many of those mushrooms you see in the woods this fall, are part of a legacy of remarkable biological cooperation.
* or plants or even animals!