The wonders of the salt marsh

New England’s Great Salt Marsh, part of which is just outside the beach parking lot, is 17,000 acres of uninterrupted, super-efficient photosynthesis, cooking faster than any other kind of landscape. It is a land fecund with organic material, absorbing more carbon ounce per ounce than forests or jungles. That makes it a good place to think about nature’s adaptation to changes in the climate.

“Salt marshes cycle a lot of carbon dioxide and grow very rapidly and as a result produce a lot of biomass,’’ says Elizabeth Farnsworth, senior research ecologist at the New England Wild Flower Society and a consultant to the Trustees of Reservations, which maintains Crane Beach and its surroundings. An acre of salt marsh can produce up to 10 tons of organic material a year, absorbing and storing carbon all the while.

Farnsworth whips out an infrared gas analyzer and slips a piece of living dune grass into its vacuum chamber. It’s a nice sunny day, and as the leaf photosynthesizes we can see the carbon readouts dropping before our very eyes. Besides all their other well-known benefits - filtering out pollutants, protecting coastal communities from floods - salt marshes are excellent carbon sinks, correcting C02 levels in the atmosphere. It’s as if the barrier marshes, aware that they are particularly vulnerable to sea-level rise, are working overtime to keep C02 increases at bay.

I love learning the names of the plants in the marshes and dunes: pitch pine, which has three-tined needles, like a pitchfork; prickly pear cactus, threatened in New England but still holding tight to sandy depressions away from shore; glossy buckthorn; bayberry; blue-green Hudsonia. I can’t help but think that if more people knew the names and habits of these charming plants it would be harder to ignore the development and pollution that threaten them.

Most of the plants have thick, leathery leaves, sometimes coated with a waxy substance or tiny white hairs, which deflect sunshine and preserve moisture. The dune grass is called Ammophilus (“sand-loving’’) breviligulata and, far from being suffocated by drifts of blowing sand, it is actually stimulated by the contact into growing more rapidly.Another natural wonder of the salt marsh is the way different species of plants and animals work together for their mutual survival. The ribbed mussel clings to the base of the marsh grass known as Spartina alterniflora for stability. It eats the plankton and other organisms in the marsh and then, to put it delicately, defecates, producing a richly nutrient mussel manure that keeps the marsh thriving.

Similarly, fiddler crabs that bore holes in the dense mud keep the marsh aerated. The majestic purple Phragmites, a reed some consider invasive, propagates through a network of rhizomes (like roots), which are hollow in order to allow the passage of oxygen into the marsh.

Such mutualism is a pronounced feature of plants and animals at the edge.

“In harsher environments you tend to see more cooperation, as opposed to competition, among the species,’’ says Farnsworth. “All of the organisms are at the extreme, and they seem to have evolved so that they interact in more positive ways.’’

Wow. It’s risky to anthropomorphize nature, ascribing human attributes to plants or animals. But can’t we wish that our own harsh conditions - of economic instability, declining resources, and environmental threats - could actually make us more cooperative? That we might see the interdependent society in the salt marsh as a metaphor for how we humans depend on each other? Or at least that we might become more aware of the precision gears on this clockwork planet, working in an exquisite balance crucial to everyone’s survival?

Renée Loth’s column appears regularly in the Globe.