What Happened to the Climate Change series?

Don't worry, it hasn't gone away, we know, we haven't wrapped it up yet. We'll finish up the climate change series later this summer. In the mean time however, we're heading to Alaska for a couple of weeks, so enjoy a few repeats on the air, read through the archives or simply occupy yourselves with the bounty of summer in Maine. We'll be back at it in July, with a head full of big mountains and big bears, and a body full of west coast sea food.

See you then!

Butterflies

 Note: This program first aired on June 21, 2014.

Summer seems like it is finally here and I have been enjoying the good weather outside as much as possible. It seems to me that there is an abundance of butterflies this year, particularly the large yellow and black Swallowtail butterflies. And earlier this spring, I noticed many Mourning Cloak butterflies around as well. It could be that I am simply paying more attention, so in the absence of hard data don’t consider this a trend. My life has led me to butterflies, which means I am seeing and appreciating more of them during the fleeing time they are here, that is all.

Butterflies under go what is called complete metamorphism, in that they have four fully differentiated stages of their development: egg, larva, though in the case of butterflies and moths the larva is by definition called a caterpillar, pupa and adult. Each of these forms is markedly different from the others, and this difference is one of the reasons we find insects so remarkable. The adult female lays the egg, typically one of hundreds of eggs, on or near an appropriate host plant for the soon to hatch caterpillar. The host plant is important, because as soon as the egg hatches, the caterpillar begins to eat, and it is usually pretty picky about what it likes (like so many kids). The caterpillar’s job is to eat and grow, which they do quite well, though most of them get eaten themselves, either directly by birds and other small hungry animals, or worse, by internal parasites. Many many other insects including certain flies and wasps use caterpillars as mobile feeding stations for their young. Eggs are either deposited directly into the caterpillar, or laid on host plant material, where the very hungry caterpillar unsuspectingly ingests the parasite egg. Once inside the caterpillar, the parasite egg hatches and the larva develops inside the caterpillar. Recall that the job of an insect larva is to eat. One source I read remarked casually that the parasitizing larva carefully eats the caterpillar alive from the inside, saving the vital organs for last, to keep the host caterpillar alive longer.  If the caterpillar doesn’t get eaten or parasitized, it will grow. We think of caterpillars as soft and squishy, but really they must follow the same rules as all other arthropods. Arthropods have exoskeletons, and must molt, or shed their old exoskelton for a new larger one when they grow. Caterpillars do the same, shedding their tough outer skin. Each time they do this, they get bigger, and may even change color or shape, each version of the caterpillar is called an instar, for example you might identify a caterpillar as “the third instar of the eastern Tiger Swallowtail”. During the last molt or shedding of caterpillar skin, what emerges is not another caterpillar, but the pupa. This stage of the life cycle is often referred to as a resting stage, but really it is anything but. It is true that the pupa (contained in a chrystalis in butterflies and which occurs in the cocoon in moths) is usually immobile, but inside the protective exterior, the entire body of the caterpillar breaks down and is rearranged into an adult. The adult body structures form from just a few cells, sort of like stem cells, called imaginal discs,  that originate in the insect egg, and are carried dormant inside the caterpillar all along. Just like us. A part of who you are comes from your maternal grandmother’s health and well being, as one of the eggs that became you developed in the embryo that became your mother inside your grandmother’s womb. Other bits of you come from your father, who continuously generates new genetic material throughout his life. As humans we take those bits of DNA and we develop, we grow, we age, we come into our fully articulated being, and we wonder where this person we’ve become came from. Just like the butterfly, emerging after so much work and shape shifting, we have to remember, we were there all along.

References:

Many online references exist for butterflies, none better than Bug Guide http://bugguide.net/node/view/81

A link from the Bug Guide site, to a California lepidopterist: http://mamba.bio.uci.edu/~pjbryant/biodiv/lepidopt/GettingIntoButterflies.htm

Bug Guide Mourning Cloak page: http://bugguide.net/node/view/3188

Good stuff on insect metamorphism from Scientific American: http://www.scientificamerican.com/article/insect-metamorphosis-evolution/

And specifically butterflies and moths: http://www.scientificamerican.com/article/caterpillar-butterfly-metamorphosis-explainer/

Alewives

Note: This program first aired on June 14, 2014.

This spring I’ve developed a bit of an obsession, with alewives. I’ve known for years about anadromous fish, those being the ones that live most of their lives in salt water, but come into fresh water to reproduce, but I’d never seen them in action, crowding up the rivers and streams, fighting the current en mass. We have ten species of anadromous fish here in Maine, including shad, salmon, two kinds of sturgeon, rainbow smelts, blue back herring, tom cod, striped bass and lampreys as well as alewives, so you would think that I would have ample opportunity see this phenomenon.  The reality is, that a. not all of them fight their way up small streams to lakes and ponds and instead spawn in the brackish main stems of rivers and b. not all of them return in high enough numbers to make a dramatic show of things. Alewives though, they come inland in large groups, filling streams with enough of their bodies that there is still a commercial harvest of them. I realized that if I wanted to see anadromous fish, the humble alewife would be my best bet.

Alewives are in the Clupeidae or Herring family, which includes seven species found here in Maine; two kinds of shad, sea herring, blue back herring, men haiden, thread herring and alewives. Several of these herring species stay at sea and do not come inland to breed, a few others, including the alewives do. Alewives are planktivorous fish, meaning they feed entirely on plankton, microscopic organisms suspended in the water column. Planktonic crustaceans make up the bulk of their diet. They make their way up coastal watersheds in New England during the spring, arriving on Cape Cod and southern New England in April, and Maine in May. It is thought that they spend most of their time in schools off shore, and wait to come up into fresh water until the fresh water discharged into the ocean warms to some critical temperature threshold, signaling inland conditions appropriate for spawning. If you cut open an alewife heading up stream you will see where its priorities lie. Most of its body is designed by evolution for propulsion, its just muscle and bone. Lots of bone in fact, like its bigger cousin Shad, alewives are especially bony fish, and seem to have an extra whole set of ribs on the bottom half of their bodies. Where there isn’t muscle there is a small internal cavity where the all the non head associated organs are found. In a female alewife heading up stream, this cavity is filled almost entirely with roe, two large sacs of eggs that she will release when she reaches the slack water of the pond or lake at the head of the stream. The males release their milt or sperm at the same time and the eggs are fertilized externally, and stick to any surface underwater. Once spawned, the extremely thin adults head back down the stream to the ocean. They are thin because not only have they essentially emptied out their body cavities of their reproductive material, they also don’t eat on this spawning migration. Once they get back down into brackish water, they resume eating with a vengeance, and if conditions are good, rapidly gain weight. Like all of the Atlantic anadromous fish we see in Maine, alewives don’t necessarily die after spawning like west coast salmon do. They can return to the same stream again the next year to spawn (most likely in fact, the same stream they were born in).

Every source you read about alewives talks about how they tie marine and freshwater ecosystems together, moving nutrients in and out of lakes and ponds, and how they are an important food sources for so many species of other fish and birds. Its like their job is to get eaten. And this is the first clue about how to see alewives. Look for hungry birds, lots of them. This spring I was driving home one late afternoon, passing by a tidal stream with a small fringing salt marsh that leads up to a pond, when I noticed two juvenile eagles at the waters edge. I got excited and stopped the car, and as I looked closer, I noticed another eagle in the tree line. As I looked further, I saw at least ten eagles, adults and juveniles congregated along this small stretch of stream, all waiting. I didn’t go down to the stream to see if there were fish, because I didn’t want to disturb this amazing conclave of eagles, but I imagine the fish were not far. I did managed to see alewives at the outlet of another local pond, they were trapped on the upstream side of a gate that was designed to keep them from attempting to go up the main outlet channel that leads to an impassable old dam, and to direct them to the fish run channel that circumvents the dam structure. I think that the fish I saw had gone up the fish run, but then came back down over the dam on their way down stream and found them selves trapped behind the gate. We opened the gate temporarily to let these fish through, as well as flush out the bodies of the ones that had died waiting. And this year I got brave and followed the hand written sign posted a few miles from my home to the house where an old timer sells the smoked alewives he dipped netted by hand.

So, I’m getting closer. I have yet to see the full expression of the spring alewife migration, but I am just an aspirant in the discipline of fish knowing. I think it will take years to learn what I need to know, which is as it should be. A creature of the water, mysterious and hard to see, can’t be, shouldn’t be known so easily, with so little work or patience or humility. That is the lesson everyone who hopes to catch fish must learn eventually, and every one who hopes to see them too.

References:

Maine State Gov site on River Run fish http://www.maine.gov/dmr/searunfish/alewife/

Want to see the alewives run? The Damariscotta Mills fish run is a great place to start: http://www.damariscottamills.org/

Henry Bigelow’s amazing Fishes of the Gulf of Maine, available online for free: http://www.gma.org/fogm/

Interesting Maine website: http://maineanencyclopedia.com/alewives/

Info on all of Maine’s anadramous fish from the Penobscot River Restoration Project: http://www.penobscotriver.org/content/4027/anadromous-fish?ext=

The definitive text on alewives in New England: The Run by John Hay, first published in 1959. It is an exquisite and humble piece of nature writing.

Climate Change Part 10: The Carboniferous Period

Note: This program first aired June 7, 2014.

Climate change, at least, the current climate change is all about the carbon. Human society is emitting large amounts of fossil carbon into the atmosphere at rates much faster than typically seen in the geologic record. We call it fossil carbon because this carbon is coming out of the rock reservoir, its carbon that hasn’t been in play in the fast carbon cycle up here on the surface for hundreds of millions of years. What we are experiencing is a major flux of carbon out of long term storage, which is then having a major impact on the atmosphere, oceans and climate system, pretty much everything here on the thin surface of the Earth on which we live. Another name for this flux of carbon is called the industrial revolution, and the industrial revolution was fueled initially by coal, so that is where we will start today’s discussion.

The fast carbon cycle, as it pertains to coal, consists of plants drawing carbon dioxide out of the atmosphere. Plants take carbon dioxide gas and water and use the energy of the sun to break up those molecules and reform them into a higher energy molecule, glucose. The energy from the sun is then effectively stored as this higher energy molecule. The glucose molecule can then be used for energy for the plant to form other structural or physiological molecules like protiens or fats, or can be directly converted into long chain carbohydrates. When the plant dies, or is eaten, organisms that include animals, fungus and bacteria break down all those higher energy molecules, and use the energy of the sun stored within to do their own physiologic bidding. As part of that deconstruction process, the molecules are converted back into carbon dioxide and water and released. That’s the basic fast carbon cycle, plants take it in, and decay lets it out.

The Industrial Revolution really began some 325 million years ago, give or take, when some interesting things began to happen on Earth, and the carbon that we are dealing with today started getting taken out of the atmosphere. This geologic era is known as the Carboniferous, because of what happened to atmospheric carbon, and the average carbon dioxide level during that time, which stretched from 354 to 299 million years ago, was 800 ppm. For reference, we started the Industrial Revolution at 280 ppm and we have steadily increased to our current 400 ppm, with no stopping in sight. It was generally warmer, but keep in mind, we are talking about a 50 million year time period, with all kinds of tectonic activity, so there was certainly climatic variation. Biologically, it was very different than today. Virtually none of the animals we know today existed. Plants had made the transition from water to land, but there were no flowering plants, they hadn’t evolved yet. All terrestrial plants were things like ferns and club mosses the size of trees. The fact that this was still quite early in Earth’s evolutionary history is an important fact to keep in mind as the story continues.

Conditions on Earth favored rapid growth of these tree ferns and tree sized club mosses, in tropical swamps that formed along the edges of the continents that now make up the Northern Hemisphere. Sea level changed repeatedly, so these swamps were repeatedly inundated with sea water, when the sea water receded, the brackish swamps continued to grow. The organic matter from these giant fern swamps built up fairly rapidly, which is a little unusual. Think back to the basic carbon cycle, plants take carbon in, and decay mediated by animals, fungi and bacteria releases carbon back out. In this case decay wasn’t happening , and each time the swamp was covered by the ocean, another layer of undecayed organic material was buried under sediment. Scientists think the reason that this swamp forest material didn’t break down was because the plants had recently evolved a substance called lignin. Lignin is a common substance today, found in wood everywhere, but at the time it was a pretty new invention. And likewise, today, lignin is broken down by white rot fungi. But because in the Carboniferous lignin was so new, nothing had evolved to break it down and decay it.  Because nothing could decay it, it built up in thick layers. So all the carbon that the giant ferns and club mosses pulled out of the atmosphere and incorporated into their bodies in the Carboniferous period got buried under sediment and over a hundreds of thousands of year period, was slowly transformed into coal.

All that carbon moved out of the atmosphere 300 million years ago, and stayed out, buried in the ground. We discovered it and realized we could burn it, and use the heat to heat water to make steam to do work, and change the world. Really, we are just returning the carbon to the atmosphere that was there in the Carboniferous. But the world was very different in the Carboniferous, there were barely mammals, let alone humans. I don’t think I want to live in the Carboniferous, but if we put all that stored away carbon back where it came from, that is just where we are heading.

References:

University of California Museum of Paleontology strikes again : http://www.ucmp.berkeley.edu/carboniferous/carboniferous.php

Fun stuff from the BBC, including videos from Wales: http://www.bbc.co.uk/nature/ancient_earth/Coal_forest#intro

Fungus (or lack thereof) may have been the key to coal formation: http://www.scientificamerican.com/article/mushroom-evolution-breaks-down-lignin-slows-coal-formation/

Time line of coal in industrial society from the American Museum of Natural History: http://www.amnh.org/exhibitions/past-exhibitions/climate-change/how-did-we-get-here/the-rock-that-burns

Info on the rise of atmospheric CO2: http://earthobservatory.nasa.gov/Features/CarbonCycle/page4.php

We may be getting ahead of ourselves here but this solutions site looks pretty good: http://www.thinkglobalgreen.org/carbondioxide.html

Giant insects: http://news.nationalgeographic.com/news/2007/07/070730-giant-insects_2.html