Of course, lagoons aren't the only places to look for salt marshes.
You'll also find them in protected bays and along the lower reaches of
estuaries, not to mention sloping foreshores sheltered from prevailing
winds. Location matters, too. Though both the Atlantic and Gulf Coasts of
North America are generally hospitable, less than 20 percent of the Pacific
Coast is capable of supporting salt marsh.
The reasons for this variability are almost too numerous to catalog. If a
coast is too steep, sediment can't settle, and emergent plants struggle to
keep their heads above water. On the other hand, gently-sloping foreshores
are often muddy, and mud is an ideal nursery for growing plants. What's mud's
secret? It's all in the recipe: a surprisingly complex mixture of clays
and silts, along with sand, fragments of marine shell, and dollops of
organic detritus. Where does mud come from? Here's a hint: Another name for
salt marsh is tidal marsh. This gives the game away. Unlike their
freshwater cousins, salt marshes breath with the tides, flooding and
drying as the water rises and falls. And with each cycle, the sea deposits a
fresh mantle of sediment. Estuarine marshes enjoy a double bounty, receiving
sediments from both sea and land, borne by tide and river. Salt-tolerant
plants take root in the resulting mud, and their roots in turn trap still
more sediment, holding it fast against the tug of the tide. As generation
succeeds generation over many years, a rich organic mortar forms. The end
product of this process is peat, and in the fullness of time shrubs and
trees may colonize the peaty shallows, as meadowland grows outward toward
Here we see the secret behind the first of the salt marsh's two pivotal
Bulwark of the Land
Salt marshes are natural sponges. When a high wind joins forces with a
high tide to send a storm surge sweeping toward the coast, the resilient
matrix of mud and interfingered roots absorbs the blow, sparing the land
from the full might of the sea. Even when this defense fails to halt the
onrush of water, the marsh endures. And when the storm waters finally
recede, as recede they must, the marsh stands in their way, recapturing much
of what the waves had claimed. The upshot? The marsh emerges from the battle
even stronger than it was before the first wave fell. Now that's triumph in
Tough as they are when put to the test, however, salt marshes also have a
tender side. In fact, they might well be called
The Sea's Nursery
Like freshwater marshes, salt marshes support a rich diversity of plant
and animal life, beginning with marine plankton and moving up the pyramid
from there. Lugworms and other marine worms flourish in the mud of the
intertidal zone, as do a bewildering variety of molluscs, crustaceans, and
other invertebrate life-forms. Land animals, too, depend on salt marshes.
Shore birds, squirrels,
deer, and muskrats come to the marsh to forage for their meals. Ospreys and
gulls build nests on land, finding rich pickings just offshore in open
water. Wading birds, ducks, and geese feed in the shallows and stalk the
fish that sweep in with each tide.
Fish. Here we come near the heart of the matter and the marsh. For
many species of fish, including some commercially important species, and for
the young of sea
turtles as well, the salt marsh provides both shelter and nourishment.
Some species move on into the open sea as adults, others (like the flounder)
remain behind to get their living in the shallows. And speaking of moving
on, salt marshes play host to countless species of migratory songbirds,
waterfowl, and waders on their semiannual flights to and from their
wintering grounds. Some stay only long enough to rest and refuel before
taking to the air for the next leg of their journey. Others stop over for a
season, or even longer.
Canoeists and kayakers, too, find welcome shelter from wind and wave in
salt marshes. But for birds and paddlers alike these refuges
are now becoming scarce. And their fate is our hands, because, like all
Salt Marshes Are Fragile
They're fascinating places to visit, but they're also easily damaged, and
the cumulative impact of thousands of visitors, even thousands of
well-meaning visitors, can wreak havoc: even a discarded plastic bag
can kill, after all. Yet other threats are far graver. Waterfront
development. Wetland "reclamation." Pollution from industrial effluent,
agricultural runoff, sewage-treatment plant outflows, and storm drains.
Erosion from wakes. Overfishing. The list is long and disheartening, and
remedies are few and far between. But the damage must not continue. Much has
already been lost. Less and less remains to save. And time is running out.
What can we paddlers do? Give wildlife and waterfowl plenty of space,
especially during the breeding season and when they're raising their young.
Pick up after ourselves (and others). Watch where we step, and even then
tread lightly. Leave our pets at home. None of these things will address the
big problems, of course, but at least we won't be making things worse. And
Salt marshes are dynamic, fluid and ever-changing. Sometimes dry and
sometimes wet, they partake of both water and land. Yet theirs is a benign
duplicity. After all, they protect the shore from the sea's assault at the
same time that they nourish the hungry. And our species is no exception.
Salt marshes protect and feed us, too. But for how long? That's the
question, isn't it?
Copyright © 2007 by Verloren Hoop Productions. All rights