The Carbon Cycle & The 6th Extinction

The Carbon Cycle

At the beginning of the Archean Eon 4 billion years ago, life emerged upon Earth in a process called abiogenesis; ie., “origin of life”. Several evolutionary processes at the molecular level of increasing complexity formed various chemicals in the early ocean, which led to cellular processes like self-replication and membrane formation. Bacteria eventually evolved and began adding oxygen to the existing volcanic gaseous atmosphere. (For a time, the bacteria went a bit crazy, creating “The Great Oxygenation Event”). Fungi, plants, and animals evolved…some crawling onto land. Plants took root, making homes for the evolving insects, amphibians, reptiles, birds, and mammals. At the atomic level of all this is carbon. Carbon loves to bond with other elements, and is the best element able to form the long chains needed for complex molecules, like DNA. So, Earth is host to carbon-based life…

…and The Carbon Cycle.

Living things breath. Plants “inhale” carbon dioxide, add water, and with the sun’s energy use a process called photosynthesis to make sugars. The plant “exhales” oxygen. The plant grows, using up atmospheric carbon. The plants get eaten by animals. Their life processes…breathing, waste-production…release the carbon back into the air and soil. Plants and animals die, get eaten by carrion eaters and macro- and micro-organisms, releasing more carbon. The remaining soil-based carbon is sequestered for 100’s of millions of years, forming reservoirs of peat, coal, oil shale, natural gas, and oil deposits. 

Atmospheric carbon also dissolves into the oceans, which hold up to 50 times more carbon than the atmosphere. The tiny plants of the oceans, phytoplankton, eat some of the carbon via photosynthesis. Other things eat the plankton, other things eat the other things, etc.; all these things eventually die, drifting to the ocean bottom. The layers of sediment form an organic-rich mud and the pressure compresses it into organic shale and limestone. Through millions of years the layers continue to sink. Heat and pressure transform the shale into oil shale. Oil percolates from the shale, upwards through the other relatively porous layers and groundwater, until it meets a solid rock layer. Thus, another method of carbon sequestration. Carbon also get stored in the rock layers thus formed. This is all naturally in balance….

…WAS naturally in balance.

The actions of anthropogenic (human) activities…burning of carbon-based materials (fossil fuels) removed from the sequestered carbon reservoirs…releases carbon back into the atmosphere as CO2 which disrupts the carbon cycle in ways severely detrimental to human existence, and the existence of most other things.

Let’s begin with the air we breath.

Land-based plants and the oceans are currently managing to take up about 80% of the carbon generated anthropogenically (by humans). The rest stays in the atmosphere for thousands of years. Scientists have found that CO2 causes 20% of Earth’s greenhouse effect, water vapor 50%, and clouds 25%; other things make up the rest. 

Earth’s atmosphere is a thin blanket of gases and tiny particles where water vapor levels are controlled by temperature: higher temps equal more water. CO2, and other materials, heats the air by absorbing solar energy then releasing it. So as CO2 atmospheric levels rise, water concentrations increase due to the increase in temps. The increase in water concentration adds to the greenhouse effect, further increasing temps, further increasing water levels, further increasing the greenhouse effect, etc. The Earth is heating up on a global scale: Global Warming.

As carbon enters an environment, it combines with tiny water droplets to form carbonic acid. As the air cools, retained water get released it as rain..all precipitation begins as rain…and the rain holds the aforementioned carbonic acid, adding to the acid caused by other pollutants, creating “Acid Rain”. Acid rain disrupts plant growth and aids in mineral breakdown. As rock is degraded, the carbon stored there 100’s of millions of years ago gets released, adding more carbon to the Earth’s carbon cycle. So of all the greenhouse gases, CO2 is the gas that regulates the Earth’s temperature more than any other, thus controlling the both size of Earth’s Greenhouse Effect and the speed of Global Warming. And Earth’s atmosphere is getting wetter, creating closer ties with the oceans.

The Oceans, you say?

As carbon as CO2 enters the oceans, the carbonic acid created is soon converted into bicarbonate, lowering the ph level and, worldwide, causing Ocean Acidification. Higher atmospheric CO2 levels are causing an increase in these actions, resulting in an increase in species mortality; various sea creatures suffer depressed metabolic and immune response rates. Oysters, clams, and shallow and deep sea corals experience higher mortality rates. 

Plankton, the basis of the ocean food chain, which happens to add 50% of Earth’s oxygen to our air, also suffers. Studies have shown negative effects of ocean acidification on plankton. Zooplankton species have calcium-based protective “shells” which do not properly form in an acidified environment. Phytoplankton photosynthesize and need chlorophyll; chlorophyll health suffers in an acidic solution. Some species of phytoplankton cannot survive in acidic and warm environments…and that’s what’s now happening. So, plankton diversity may decrease and species’ population will redistribute as they adapt to changing conditions. The implications of population redistribution and decreased diversity will disrupt the ecosystem and the food chain in ways now not fully understood. 

So, we’ve disrupted the carbon cycle, adding atmospheric carbon faster than the normal carbon cycle can address it. Acid Rain, Greenhouse Effect, Global Warming, Climate Change, Ocean Acidification, Bug Die-Off, Diminished Species: all terms coined in my generation. The latest term?…

The Sixth Extinction

Five mass extinction events during the past 540 million years have happened, all involving worldwide extermination of marine species over the course of thousands to millions of years. Each event was preceded by major changes in Earth’s carbon cycle…a change we currently seem to be experiencing. Some scientists point to carbon cycle data suggesting that the sixth event may very well be happening now. The difficultly is that previous cycle data have spanned thousands or millions of years, while the current data base involves only a century or so. The magnitude of our current carbon cycle needs deeper study…

…which has been done. 

Daniel Rothman, professor of geophysics in the MIT Department of Earth, Atmospheric and Planetary Sciences and co-director of MIT’s Lorenz Center, has published an article in Scientific Advances, identifying “thresholds of catastrophe” in carbon cycles which, if exceeded, would lead to an increasingly unstable atmosphere, and as his data shows, mass extinction. 

Rothman found that the critical rate for catastrophe is related to a process within the Earth’s natural carbon cycle, in which organic carbon sinks to the ocean bottom and is buried and becomes sequestered. If this rate of natural sequestration is exceeded by carbon being added to the cycle…by burning fossil fuels for example…the carbon cycle becomes unstable. 

His study shows that historic mass extinction follows if one of two carbon cycle thresholds are crossed: long cycles with relatively slow carbon level changes that happen faster than Earth environments can adapt; and short cycles with a relatively quick, high level change. The latter change is what we are now experiencing; excess carbon circulating through the oceans and atmosphere, resulting in global warming and ocean acidification. 

His study indicates the crossing of the carbon threshold by 2100, using projections in the most recent report of the Intergovernmental Panel on Climate Change. IPCC considers various politically-enacted carbon emission-limit policy scenarios in their models, which all show that by 2100, the carbon cycle will either be close to or well beyond the threshold for catastrophe.

“This is not saying that disaster occurs the next day,” Rothman says. “It’s saying that, if left unchecked, the carbon cycle would move into a realm which would be no longer stable, and would behave in a way that would be difficult to predict. In the geologic past, this type of behavior is associated with mass extinction.”

The Monarch Chrysalis

“When the caterpillar is a full grown fifth instar caterpillar it is ready to molt the fifth time  to become a pupa, or chrysalis. The caterpillar will begin to wander until it finds an appropriate place to create its chrysalis. It will lay down a silk mat, like it has every time that it has molted before.  But this time it will spend time creating a small wad of silk–a silk button—in the middle of its mat.  When it is ready it will grasp the silk button with it last prolegs and hang upside down. This is called hanging in “j.”  

See more pictures and read more here:


In 1939, mining engineer Oliver Bowles estimated 259,000 miles of stone walls have been built in New England. Damage from theft, strip-mining for commercial sale, and demolition for housing construction has left about 100,000 miles, according to the Stone Wall Initiative, (from which most of this entry is gleaned). Re-building these iconic land forms causes archaeologic sites to be changed into modern architecture, resulting in the loss of cultural significance. A bit of saving grace is that many stone walls are described within property deeds, in which boundaries are memorialized by the wall’s locations…giving them monument status and a bit of protection from removal. Some folks realize the benefits of stone walls and have enacted state laws and municipal ordinances for their protection and considerations. 

So, what about stone walls? How’d the stones get there? Where’d they all come from? Well, comets and asteroids containing ice formed from space dust and slammed into each other, eventually forming Earth. Ice turned to water thanks to the Sun and collected into a great ocean. Polar caps formed and glacial periods followed. Back-and-forth glacial movements along with erosion from winds and rains eroded Earth’s surface, dumping rocks everywhere. The glaciers were very generous with the New England area! The settlers needed someplace to set the rocks they cleared for their crops, so walls served to denote field boundaries and helped to contain livestock. 

But another creation is offered by these structures…habitat!

The stone provides a surface upon which lichens will live. Lichens provide an inviting substrate for various mosses, ferns, and trees to root; black birch are especially fond of beginning their lives within a mossy world. These rock-loving plants provide the little bugs upon which many returning birds rely to recuperate from their migrations, and which help sustain other, over-wintering creatures: turkey and other birds, various amphibians…and the animals that eat them!  

Cats, squirrels, and foxes use them as travel lanes, and the extra elevation helps them spot prey, or predators. Endangered Blanding’s turtles migrate to breeding sites along stone walls, where the leaf litter provides moisture and there’s more protection from predators. Chipmunks and white-footed mice are attracted by the protection, while mink, snakes, foxes, and owls await their emergence. Stone walls literally make our landscape come alive, creating a keystone habitat and the basis for a food chain. 

Stone walls create their own ecosystems. Being attached to, and rising from, the soil and earth, summer’s heat and winter’s cold are tempered, easing the effects of temperature extremes on the many reptiles and amphibians that make their home within the walls protective stones. The base is cool and moist, the crevices like tiny caves; the top…warmer, drier, and more barren. One side might be woods, the other field. Many animals are attracted by the diverse habitat made by the redirection of winds, affording protection on the leeward side. Snow pack and rainwater drainage is heavier on the uphill slopes, causing soil run-off to be deposited there thus providing a rich growing medium for plants to thrive on one side, and not quite so much on the other side; Often there will be shade-loving plants and sun-loving plants on either side. These habitats create a diverse ecosystem throughout the length of the wall, strengthening the overall health of the surrounding landscape.

Pence Eco-Center at McKeon Reserve Receives Donation

Kennebunk Savings Bank Helps Local Land Trust Project

July 11, 2019

Sanford/Springvale Mousam Way Land Trust is thrilled to announce the generous $10,000 donation from Kennebunk Savings Bank towards the Trust’s ongoing community-orientated effort: Sanford Community Garden at the Pence Ecology Center in The McKeon Environmental Reserve in Springvale. The Center and Garden, separate projects but growing together, will both be well served by this thoughtful gift.

Brad Paige, Kennebunk Savings President and CEO, explained the Bank’s Community Promise program, begun in 1994 by then Bank CEO Joel Stevens, who thought that a mutual institution should pay dividends to not only its investors, but also to its communities. The subsequent 25 years has seen the Bank donate $13 million to more than 1,200 organizations. And in this 25th year, a record $1 million will shared to area non-profits. Along with this, the Bank’s dedicated employees will have volunteered personal time at local non-profits, nearing the 10,000 hour mark in 2019. 

As stated on the Bank’s Facebook page: “When we heard about the Sanford/Springvale Mousam Way Land Trust’s new community gardens and ecology center for environmental education, we knew we wanted to provide support for this amazing project. In addition to its educational focus, the center’s community gardens house 24 raised beds that will be used by local nonprofits and families to grow healthy, fresh food. The collaborative spirit of this project truly resonates with us and we’re excited to see the remainder of this project come to fruition!”

Mr. Paige stated that Kennebunk Savings Bank has been very successful in its communities over the years, helping to build many homes and businesses, so to help preserve land for future generations is the ethical and moral thing to do. Mousam Way Land Trust is grateful for the Bank’s forward thinking and their Community Promise program donation.

Community Garden at the Farm Walk!

The Mousam Way Land Trust is pleased to be partnering with the local horticultural community’s farms during Springvale’s 5th Annual Farm Walk this summer, July 28. During your visit, via shuttle if you wish, you’ll be offered: 

  • Tours of Sanford’s brand new Community Garden project; 
  • The University of Maine Extension Service’s Kids Can Grow program demonstrated by the York County Master Gardener Volunteer program;
  • An introduction of the Trust’s growing David & Linda Pence Community Ecology Center;
  • An assortment of Kids’ Games, including a giant croquet game that kids can run through, or push/kick huge inflatable balls;
  • Free Shain’s Sea Dog Biscuit ice cream bars!

More info is here. 

Sanford Community Gardens receive grant

(As reported in Journal Tribune, June 27, 2019)

SPRINGVALE — The York County Chapter of the University of Maine Extension Service Master Gardener Volunteers, and the Maine Master Gardener Development Fund has announced the awarding of a $500 grant to the Sanford Community Gardens.

The Maine Master Gardener Development Fund supports the establishment or expansion of horticulture-based educational projects in communities across Maine.

Located at the Pence Community Ecology Center in the McKeon Environmental Reserve on Blanchard Road in Springvale, Sanford Community Gardens has begun its first year of providing raised bed plots where folks who lack access to suitable land can grow their own organic vegetables, flowers, and herbs.

More information can be found here:

Local Master Gardener Project Coordinators and Mousam Way Land Trust Directors form the Community Garden Advisory Committee which oversees the project. Master Gardener volunteers assist the raised bed gardeners with all aspects of gardening: initial soil testing interpretations, compact and season-extending gardening methods, organic weed, pest, and disease controls, to safe harvesting techniques and winter bed preparations.

For more information about the Master Gardener Program, email:

Lending a Hand

(As posted on Journal Tribune Newspaper website).

As hundreds of volunteers from local businesses fanned across York County for the United Way’s 2019 Day of Caring event, these Pratt & Whitney employees  worked alongside Mousam Way Land Trust members at the trust’s Pence Community Ecology Center at the McKeon Reserve to clear areas for a future access road and parking lot. They also built a stone berm along a future greenhouse area, and installed fencing to help protect the Sanford Community Garden from hungry, determined deer and other critters.

Wood Frogs

The duck-like barking sounds of the wood frog are usually the first to be heard by our singing amphibians, as they call out to their mates from their vernal pool breeding sites.  

Wood frogs are found in all types of forests, preferring damp areas like ravines, forested wetlands, swamps and bogs while foraging for a variety of insects and small invertebrates, including spiders, beetles and moth larvae.

 At 2”- 2 3/4” long, wood frogs are identified by a white line above the lip, a dark “robber’s mask” across the eyes, and their color ranges from brown, rust to shades of green…with the ability to change color. Sexes can be distinguished by examining the shape of the webbing found in the hind toes; females have concave webbing, while males are convex.

Wood frogs emerge from hibernation when warm rainfall thaws them. They participate in a yearly migration that brings them to vernal pools for breeding, starting in late February and March. Males search for a mate by hugging other frogs until they find one who is round enough to be carrying eggs. Females lay approximately 1000 eggs, often in the deeper sections of the pools and often attached to other egg masses which in turn are attached to vegetation within the pools. Eggs will hatch in 10-30 days, depending on the temperature. The larval stage, known as tadpoles, feed on algae, detritus, and the larvae of other amphibians…taking a little over a month to mature into frogs. Tadpoles die if the pool dries up prior to growing into a frog.

It is the only frog species that survives above the Arctic Circle, aided by the rare ability to withstand partially freezing. It will not urinate all winter…sometimes for 8 months in Alaska. Microbes in their guts recycle the urea, which begins to accumulated in tissues as winter approaches; and glycogen in the liver converts to glucose as the body begins to freeze. Both urea and glucose act as a sort of anti-freeze, restricting ice formation and cell damage while its heart, brain, and blood flow stop…becoming dead by conventual definition! Cells continue a limited function with a loss of cellular communication. Frogs can survive many freeze/thaw events during winter if no more than about 65% of the total body water freezes. The ability of wood frogs to successfully complete their winter survival transformation is related to the amount of insulating snow cover that exists, as well as how deep a frog is able to burrow into its winter hibernacula. Warmer temperatures bring a slow resumption of function, and they make their way to a nearby vernal pool to shower us with their springtime barking. 

As climate change continues to redistribute snowfall, wood frog habitat that begin to exhibit thinner winter snow cover are likely to suffer population declines.