"The reef was a living thing . . . . for only the surface is occupied by living polyps."
this past, we can see in the present a repetition of the pattern of recurrence
of earth processes of an earlier day.
Carson, The Edge of the Sea,
p. 196-97, 201.
tropical sea's possess interconnected margins.
The shoreline tropical
oceans have fascinated naturalists from Charles Darwin and Louis and Alexander
Agassiz to Rachel Carson because of a curious blend of flowering grasses,
flowering forests and underwater coral reefs all bound together in a productive
unit by the warmly translucent sea penetrating an otherwise less productive
landscape. She informed the public of "The living coral coasts of the world," are capable of building "massive structures of the reefs. . . only where the coral animals are bathed by waters warm enough to to favor secretion of their calcareous skeletons." (.p. 191-192) And in a evocative reminder of the planet's larger context, built by the the coral animals, she wrote "the shaping hand is the the hand of the sea." (p.193)
Brown, Tompkins and
Adger also agree that "Coral reefs are important component of coastal
ecosystems, providing a range of valuable economic, social and environmental
services at the local, national, regional, and even international levels."
(p. 14) They insist that "Reefs also provide socially beneficial
ecological services" that can best be summed up as the rock lobster
"fishery is dependent on the health of coral reef systems."
(Ibid.) Numerous research shows that mangroves, which are salt water forests,
extensive sea grass beds, which are flowering grasses, and reefs are distinct
habitats that work in unison to sustain nearshore tropical fisheries.
Carson describes "Dark
patches like the shadows of clouds are scattered over the inshore shallows
of the reef flats. Each is a dense growth of sea grass pushing up flat
blades through the sand, forming a drowned island of shelter and security
for many animals." There is, as she points out a diversity of grasses
"About the Keys these grass patches consist largely of stands of
turtle grass with which manatee grass and shoal grass may be intermingled.
All belong to . . . the seed plants." (p. 230).
and lasting features of these distinct but related ecological groupings
of saltwater forests, grasslands and rock reefs are that
1. the form the
biologically productive foundation of coastal systems because plants
and algae transform water and sunlight into food, fuel and fiber necessary
for all ocean life.
2. provide niches
for other creatures, as Carson notes "In the islands of turtle
grass many animals find food and shelter." (p. 231).
such as echinoderms, snails and clams, together with turtles, sport
and commercial fisheries are dependent at some time in their lives on
the submerged grasses, emergent trees, and deep water corals.
"This coral coast
is the drowned world," Carson reminds us "of the offshore reef
and the world of the shallow reef flats with their fringing, rocky rim;
it is also the green world of the mangrove, silent, mysterious, always
changing -- eloquent of a life force strong enough to alter the visible
face of its world."
Carson is clear to
delineate how the three associations or groups of foundation systems work
together to protect, produce and prevail along otherwise desert coastal
areas where salt water, hot weather and barren sands would otherwise limit
plants and animals. She writes "as the corals dominate the seaward
margin of the keys, the mangroves possess the sheltered or bay shores,
completely covering many of the smaller keys." She too notes that
they grow "building an island where once there was only a shoal,
creating land where once there was sea." (Edge of the Sea, p. 240).
The entire collection
of hard and soft corals forming the reef, the salt tolerant coastal forests,
and the vast submarine prairies of diverse sea grasses where fish and
turtle graze, are of inherent and economic value. Brown, Tompkins and
Adger, using recent studies about the commercial value of natural areas
conclude that " the value of these ecosystems [mangrove and coral
reef ecosystems] is in the order of $6,075 per hectare (ha) for coral
reefs and $9,990 per ha for mangroves, based on data published by Costanza
and others (1997)." The values associated with these mangroves and
- A. coastal protection
- B. nutrient cycling
- C. food production
- D. recreation
(Making Waves, pp. 4-5.)
- E. clean water
As these three authors
demonstrate, "Economic values of ecosystem goods and services emphasize
only on particular metric and fail to capture some of the ecological complexity
of coastal ecosystems." (p. 7) They note, for example the importance
of site and region specific shapes of shores in determining the more precise
value of their services to adjacent communities. "Estuaries are among
the most vigorous of these areas," they note "and are characterized
by high functional diversity, often making them ecologically resilient
to perturbations." While estuaries are more resilient and widely
dispersed globally than are corals, each are significant coastal production
units that Brown, Tompkins and Adger note that "the availability
of goods for direct consumption from coastal ecosystems such as fisheries
is likely to be correlated with the overall net primary productivity (NPP)
of the ecosystem."
For nearly 200 years
the scientific lessons gained from studying the seashore have now been
better understood and even quantified revealing the role of biological
production to the more accountable values of coastal resources. In addition
to scenic and psychologically therapeutic values, these economic assets
are examples of what is being lost as we crowd along ocean shores to spy
on the ever rising seas.
Waves, pp. 4-8. Edge of the Sea,
We have seen now four
types of edges: rocks, beaches, bays (estuaries) and reefs.
"edge effect" is an example of the anomalous character of the
shore. Where land and water intimately intermingle we expect the unexpected;
anomalous creatures thrive. The edge effect generally occurs wherever
an overlap between one ecological community and an adjacent neighboring
community exists; the overlap increases biological productivity because
a greater density and richer array of creatures inhabit these edges, than
either of the adjoining land or deeper sea communities.
As an ecotone between the deep sea –– Coral reefs are diverse productive boundaries –– beside terrestrial coasts.
Coral reef loss