Forests of the Sea

By Michael Caduto

Most of the oxygen in the atmosphere is generated by the sea. —Sylvia Earle, Oceanographer & Founder of Mission Blue

Climate is what we expect, weather is what we get. —Mark Twain

Conversations in the North Country often focus on the vagaries of our weather. These days the talk frequently turns toward global warming, and no wonder. Since 1900, temperatures in Vermont have risen some 3°F. Temperatures during the past decade have been the highest ever recorded. Nighttime temperatures have risen especially high in recent years.

I moved to Vermont in 1981, and never would have imagined experiencing a change in climate in my lifetime. If you have also perceived that Vermont is gradually shifting to a climate regime more akin what we normally associate with central and southern New England, then your observations are spot on. After considerable sleuthing among meteorological records for various cities in New England over time, I discovered that the mean annual temperature of Montpelier is now equivalent to what the mean annual temperature was in Pittsfield, Massachusetts two decades ago—a city that is 130 miles south of Montpelier (as the crow flies).

Considering that nearly 80 percent of the land area in Vermont and New Hampshire is forested, it’s not surprising that conversations about climate change and forests usually focus on the amount of  carbon that leaves can absorb from the atmosphere, thus mitigating the impact of climate change. It is estimated that, on average, each acre of Vermont’s forestland sequesters about the amount of carbon generated per year by the exhaust from 62 gas-powered vehicles. Worldwide, forestlands absorb 7.6 billion metric tons of carbon from the atmosphere annually, which is about 1.5 times the carbon emissions produced by human activity in the United States each year.

But the role of forests goes well beyond absorbing and storing carbon. Most people are familiar with the fact that our trees and other photosynthetic plants also generate oxygen in their leaves. But did you know that most of the oxygen in the air we breathe comes from oceans? From 50-80% of the oxygen created on Earth is produced by microscopic marine algae called phytoplankton that live in the zone found within 650 feet or so of the ocean’s surface where sunlight can penetrate. Each year, these tiny organisms, mostly dinoflagellates and diatoms, also absorb more than 50 billion metric tons of carbon from the atmosphere. In 2021 and 2022, global CO2 emissions reached new highs of some 37 billion metric tons. It is estimated that oceans absorb about 1/3rd of the CO2 produced by human activity.

Phytoplankton also form the base of the ocean food web, being eaten by a vast array of marine life, including krill, shrimp, jellyfish and snails. Krill, which are small crustaceans that resemble shrimp, are in turn eaten by everything from whales and squid to seals, seabirds, sharks, salmon and sardines. From seabirds like auklets and shearwaters, to giant blue whales—the largest animals that have ever lived—some species subsist almost entirely on krill.

During a recent Q&A with Captain Paul Watson—which followed a screening of the film Watson as part of the Climate Change & Sustainability Film Series hosted by Sustainable Woodstock and Pentangle Arts—one of Captain Watson’s major points was that humankind’s survival depends on phytoplankton. These microscopic organisms are an essential source of the oxygen we breathe, they form the base of the ocean food web and serve as the largest carbon sink that is mitigating global warming.

While individual phytoplankton may be lilliputian to our eyes, considered together they function as immense forests of the seas that cover 71 percent of the surface of our home planet. Living in a land-locked state like Vermont that is dominated by trees, and where oceans are not on our daily horizon, it is easy to overlook the seas. But we do so at our peril, and that of the multitude of other lifeforms with whom we share this planet.

As with many environments in recent decades, our oceans and their spectacular variety of lifeforms are in rapid decline. Recognizing the dire straits of marine life, and following years of halting discussions and negotiations, on March 4, 2023 delegates from more than 190 countries met at the United Nations in New York and signed a groundbreaking accord to protect ocean biodiversity. This agreement is critical for reinforcing the commitments made at the 2022 U.N. biodiversity summit, COP15: to protect some 30% of the land and seas as critical habitat for plants and wildlife.  The biodiversity treaty includes, for the first time, plans to create protected marine environments in international waters, which account for two-thirds of the total surface area of the ocean worldwide.

What You Can Do:

The familiar seaweeds that dominate the coastline are kin to the microscopic phytoplankton that dwell in the upper layers of the ocean. Photo: Michael J. Caduto.”


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