Acadia National Park - FLOW: Watersheds Part 4

Photosynthesis produces sugar by combining carbon dioxide and water in the presence of sunlight. It is the biochemical engine that runs almost all life on earth. Geothermal energy and fermentation power other living systems, but the world we know depends on the capture of solar energy in green plants. To sustain life, the process must persist over time, not be a sporadic affair. Carbon dioxide is reliably available in the air, but water comes and goes with the weather and seasons. It is most reliably to be found in the soil. The wonder of green plants is that they form a bridge between air and soil, tapping one world through their leaves, the other through their roots. The genius of plants is in bringing the two worlds together through the flow of sap up and down their stems, creating an entirely different realm based on energy held in sugar and starch.

The vascular (circulatory) system of plants is an extension of the watersheds in which they grow. Powered by evaporation through the surface of leaves, a lifting force draws water taken in from damp soil upward into the presence of chlorophyll, where it intercepts energy from the sun, ionizes, and frees a hydrogen ion that triggers the process leading to the production of glucose--containing energy in a form plants can use for maintenance, growth, repair, reproduction, and defense.

With roots in the soil, leaves in the air, vascular plants have the best of both worlds. If they were not able to rise above the earth to spread their leaves in the sun, or able to draw water up to those leaves, plants would exist only in areas where water, air, and sunlight come together at ground level--shady and humid places such as where nonvascular plants like mosses and liverworts grow in glens and at the bases of cliffs, or in shallow streams and ponds.

But by enabling the aerial, sunlit world of wind and leaves to combine with the watery world of soil and roots, plants bring two aspects of a watershed together, the upper and lower, in a way that radically expands Earth"s potential for growth.

Thinking in terms of watersheds on Mount Desert Island opens the way to considering the biointegrity of the island as a whole natural system. Though we are used to thinking of the island as being divided into four towns plus a national park, as far as the natural functioning of the island ecosystem, that is an artificial breakdown. Though the watershed of Long Pond, for instance, lies half in the town of Southwest Harbor and half in Mount Desert, or from another perspective, half in Acadia National Park and half in local towns, the water flowing through that watershed is unaware when it crosses boundaries between human jurisdictions. Thinking in terms of the biointegrity of the watershed of Long Pond as a whole allows us to transcend our everyday thinking in terms of private or public property to understand how it makes possible the island landscape that it does.

Watersheds are integral systems that receive precipitation, store it, and distribute it through the growing season for the benefit of all local residents (plant, animal, and human). Watersheds nourish every segment of the island landscape, both in and outside the park. Since all life depends on water, watersheds are basic units of natural function on Mount Desert Island. They affect the health, scenic beauty, quality of life, and economy of the region as a whole.