Imagine an island, fringed by the most magnificent underwater world. Where startled travelers humming in occasionally on small planes, look with disbelief and wonder at fringing reefs that seem to stretch for miles from this low-lying land. Imagine a place where just a decade ago, simple fishermen, in the abundance they enjoyed each day, would bait their fish traps and fertilise their gardens, with freshly caught lobster! Today, the waters are still unpolluted, reflecting the azure of brittle skies above, and mirroring the pale pure sands beneath them. Here, the fishes of the coral reefs are still abundant, though they have been fished for years. The brilliant tones of parrot fish, the reds of snappers, the darker hues of groupers and the multi-coloured varieties of angelfish and sergeant majors are just a few that make up the underwater rainbow that includes countless corals, many coloured sponges, seaweeds and sea grasses.
Along the shores, signs of large white sea urchins can be found; some, wash ashore still living, when the seas are rough. There is no shortage here, of these creatures which are so highly prized in other Caribbean islands, that they have been over harvested and grow only small and sparsely in polluted coastal waters. But not on this island. In the waters around the reefs the beautiful Queen Conch, which is close to extinction in many parts of the Caribbean, is still seen in great abundance. At a quiet cove at the end of one wide beach, a wide long hill of conch shells is carefully piled - astonishing reminders of the rich harvest of food and income that the sea has provided. The conchs, most of them large and thick-lipped from age, lie weathered by the salty air and the woman whose husband harvested them, tells of the many other beauties that they have looked upon, in the waters just outside their home.
The boat that has been their means of livelihood for all these years, is double bowed and scarcely four feet long, but the woman tells how they have tussled with a shark, outwitted crafty sea turtles and brought ashore wonderful seaside treasures on this little craft. Inside, amongst the homely clutter, the prize catches are shown by the old lady and her attentive grandson: male and female emperor helmet conchs, huge enough to adorn the head of the most imperious warrior
Upon other shorelines, birds fill themselves with fish, swooping and diving for their prey. Pelicans with breath taking wingspans soar above then plunge the surf; Magnificent Frigate Birds sail imperiously on the air; bridled terns, like red lip-sticked ladies seem to converse quietly amongst themselves on the most seaward sides of rocky promontories. Just behind the sand dunes, other bird life emerges: squat wild ducks appear occasionally and little blue herons, startled by the presence of human intruders, flap off, perhaps perturbed.
In the shallow salty ponds that form in the gentle depressions just inland, a host of winged waders feed and fly. These are for the most part, amazingly tame. Without a memory of bird hunting on this island, hoards of these birds congregate, especially at evenings, walking on their elongated legs and dipping their long thin bills into the salty sands which teem with microscopic life. Sandpipers, plovers and stilts, are just some of the birds you can find there. Most outstanding amongst them are some of the larger birds which, when they take to flight on their starkly coloured black and white wings, look like a crowd of tuxedo-dressed gentlemen on the wing!
But here on this island, changes are slowly coming and the clean waters and the pristine reefs, the wide, peaceful salt ponds and the tame shore birds will not remain untouched. The environment is slowly changing; not just through the force of hurricane surges or unexpected rains; long lasting human induced changes are coming to this environment. Large hotels have already been erected and now in the bays where once only fishermen came, larger luxury vessels are seeking a mooring. On distant sandy spits out in the ocean, yachtsmen weigh anchor, careless of the corals the may smash or the fish that they may spear during a day's leisure- filled activities. On the beaches, .~: not only sea urchins or abandoned conch shells are found, for now the litter is not just driftwood and shale but plastic bags and bottles that have drifted in perhaps from some nearby "more developed" island. Uneasy inhabitants wonder how long it will be before the poisonous outcomes of unbridled economic development will scrawl their tired tales of pollution and despoliation on their own island.
Already many of the local gardens have been abandoned for the ease of grocery shelves, packed tight with foreign goods and the good earth, for the most part, lies fallow. In garbage bags piled beside the houses, the waste that bulges with wrappings and cans, reflects new preferences for imported goods and tastes. In some places, sand is stealthily stolen from beaches to be used in construction, sometimes under the cover of night. As the dunes crumble and the waters gradually wash in, old haunts of Sunday picnickers are being permanently destroyed, while huge houses, take root on the dry hillsides. New roads are being built and now trucks speed loudly where once people walked, in quiet.
This is a true story
of an island in the Caribbean, whose natural environment has been peculiarly
preserved for much longer than many of her neighbours. But the story of
this island stands like a parable for the rest of us in the Caribbean,
where strides to economic development have been made at the expense of
the same natural resources on which this development depends.
From a drop to a thousand fathoms
Our Caribbean islands and mainlands share many features. Receiving abundant sunshine, commonly identifiable ecosystems consist of mangrove swamps, sea grass beds and coral reefs. Beyond the reefs, the seabed drops sharply to the ocean depths. Different living creatures inhabit each domain, ranging in complexity from single-celled organisms to the giants of the sea.
"One droplet of sea water under a microscope
can reveal a
magical realm of tiny flashing bracelets,
pendants, needles
and anchors. Each infinitesimal creature
manufactures its
own exquisitely formed house from the minerals
in the sea
around it, building the shining walls out
of the same silica
that sand is made of..."
LIFE Nature Library, 1969. THE SEA
At the elemental meeting of water, land and sun, the tiniest of living creatures of the sea are to be found. Some of these propel themselves freely through the water like animals, while manufacturing their own food directly from the sunlight, as do all plants. They are called dinoflagellates. Other single celled plants are actually various types of algae many of which belong to the group of single-celled living creatures called diatoms.
"The diatom is "the meadowgrass" of the
sea, and thousands
of kinds of animals, from protozoans to
whales, graze its
pastures. The diatom reproduces at so rapid
a pace that in a
month it may have a billion descendants."
LIFE Nature Library, 1969. THE SEA.
Shrimp in the "flowers" and grasses
Sea anemones resemble bunches of flowering plants
but are in fact small marine animals. Many types of anemones have small
creatures living amongst their flower-like tendrils. Some of these relationships
represent a type of "commensalism", which literally means, "eating at the
same table". The Spotted Cleaner Shrimp is often found associated with
a variety of anemones: the Corkscrew, the Branching and the Giant Anemone,
commonly known as the Pink-tipped Anemone. Sometimes purple-grey in colour
or else green, the Arrow Shrimp blends in well amongst purple sea plumes
or green turtle grasses where it prefers to feed.
A constant criss-crossing of relationships occurs
between creatures on the hunt (the predators) and those that fail toescape
them and get eaten (the prey). Other relationships occur between animals
that live and feed together. There's a wide choice of menu, that varies
with the seasons, times of dayor night as well as the health of the entire
system that the creatures inhabit. This is part of the living food web.
One thing is certain, neither the simple food chain nor entire food webs would ever occur without the sun. As the sun's heat causes water to rise and clouds to form, ocean currents to swirl and winds to blow to and fro', so the sun's light provides "the first morsel of food" in the intricate feeding cycles. Plants - from the tiniest phytoplankton floating in the open ocean to the tallest tree - all contain chlorophyll, the unique substance that makes plants green and captures the sun's energy; added with water, carbon dioxide and other minerals, plants turn this into food.
It is this energy and biotic matter, that passes
from one living creature to another. Animals cannot make their own food,
entire world of consumers, including human beings at the t the food pyramid,
depends on plant life to provide the basic source of their sustenance.
Animals get energy from eating plants directly, or by eating other animals
that have consumed plants.
These all form the basis of life in the sea and along with other plants found there (like sea weeds and turtle grasses) are recognised as the primary producers manufacturing their food directly from the sun. Animals of all sizes and categories belong to the groups of secondary and tertiary consumers depending on how far up they participate in the food chain. A very simple food chain that shows the dramatic stages through which food and energy pass from producer to consumer, can be found in the cold Antarctic region. it starts with diatoms and dinoflagellates. These are eaten by simple crustaceans, such as krill which later are devoured by Blue Whales.
In most living environments there are many choices
of food on which creatures may feed. Though a food chain gives a good idea
of how feeding occurs, from the simplest life forms to the largest, a better
picture of what actually happens, is that of a food web. Unlikely partnerships
occur where alliances happen to enhance the search for food and for survival.
Some of these are symbiotic - where more than one creature lives together
in a mutually helpful situation. This is the case with tiny organisms called
zozanthellae, that live within the tentacles of coral polyps. These microscopic
animals give corals their colours, while also finding a safe shelter amongst
them. They help trap passing creatures on which the corals feed.
In recent years, rises in sea water temperatures
have been linked with some corals' expelling of their resident zozanthellae.
When this happens, the corals lose their colour in a process not yet fully
understood, termed "coral bleaching". As a result, the corals also die.
But though the sun may seem to be an infinite
source of energy and light, its benefits are not limitless. Apart from
the fact that some scientists believe that one day the sun may burn out
- perhaps millions of years from now - there is another factor. The web
of life depends on plants that use the sun. If these primary producers
were destroyed, the web of life would collapse. If they are badly damaged
the web of life will suffer, on land as in the sea. Plants, big and small,
must remain in a healthy condition to keep on making food from the sun.
The recycling of this energy through the food web must never end, if all
creatures are to continue to live.
Within the food web there are also creatures who
live on deador dying things. Their job, although it may seem repulsive,
actually provides an important function, cleaning the environment of decaying
and dangerous matter and recycling the energy and nutrients within these
things, back into usable forms. These "decomposers" as they are called,
break down complex plant and animal material into simple elements, like
carbon and nitrogen. These can then be reabsorbed by plants. When these
are combined with energy from the sun and other needed elements, plants
grow and there is a "new" recycled food supply for hungry creatures.
Food webs occur in specialised locations. These
natural habitats are linked systems, so that what happens in one will inevitably
impact others. Many of the vital activities which relate to Caribbean people's
livelihoods and survival, depend on these ecosystems.
Most people regard them as a nuisance: smelly, filled with mosquitoes, useless for normal agriculture or development. Relatively few may use them to support their livelihoods, gathering oysters, trapping fish, using their wood for timber or tanning, or simply enjoying their quiet beauty or bird life. Mangroves in fact provide an invaluable purpose to whole islands and coastline communities. Their special roots that can grow in brackish and watery conditions, help trap silt and gradually extend the coastland into the sea. The forests of red, black, white and button mangroves, protect shorelines from tidal changes and hurricane surges. When floods occur from inland rivers, their roots help to slow silt-laden waters, so providing protection for organisms that would otherwise be damaged, in the nearshore sea. Water purification, peat formation and the conservation of soil as well as groundwater, are included amongst the physical functions of the mangrove swamp. Without them there can be severe coastal erosion, loss of property and land.
Mangroves provide an entire world for communities of living creatures that spend part or all of their lives in them. Many sea creatures come here to spawn. in the quiet still waters of the mangrove swamp their young can grow in a protected area, which is abundant in suitable food. Part-time visitors include lobster, shrimp and various fish species. A few species like the tarpon, live here always.
Other creatures make mangroves their home. The leaves of mangrove trees provide food for many primary feeders. These include the fiddler crabs and mangrove tree crabs.
Many decomposers continuously feast on the mangrove leaves in decay. Barnacles, oysters, worms and some crustaceans all dine on the sodden mangrove forest floor. Microscopic organisms, finish off the task of recycling the energy and nutrients that first were manufactured in mangrove leaves.
In contrast, a variety of birds come and go according
to migratory cycles or patterns of feeding, mating and nesting. Many of
these waterfowl provide attractions for locals and tourists, who enjoy
viewing wildlife.
Winged giants of the blue lagoon
0n the quiet island of Barbuda, the half forgotten
sister isle of Antigua, an awesome colony of Magnificent Frigate Birds
is thriving. Numbering in the hundreds,, these birds roost resplendently
amongst the mangroves. Little economic activity has disturbed their ancient
habitat. These birds were named by landsick sailors of a by-gone age, travelling
in frigates, who watched their soaring flight on wings that might reach
as wide as seven feet. They now re-create ancient seasons of mating and
nesting. Males inflate large red balloon-like pouches beneath their bills,
to catch the eye of potential mates, in this spectacular courting ritual.
Visitors may travel quietly amongst this colony of birds, in small shallow
draught boats guided slowly through the water. In this mangrove swamp,
other wonders can be seen like the curious Upside-down Mangrove Jellyfish
that looks like some miniature garden swirling on a tiny lost planet. Other
pleasures may include lunching on fresh lobster, chosen from a stash of
live creatures from the blue lagoon.
Like some magnanimous benefactor, the mangrove
habitat benefits the land on its inshore side, the seas and reefs on its
ocean side as well as a host of creatures that live within its intricate
system of leaves, trunks, branches and roots. Merely as a place of re-creation
and enjoyment, this habitat is vital to our existence.
"Developers" with eyes set on short term economic
gains, without a sense of their overall function, see mangroves as being
better suited for sites of garbage dumps, rice cultivation, land reclamation
- even road building and housing or airport development. In so using mangroves,
they fail to calculate longer term economic, social and cultural losses.
As open pastures give a grazing ground tI o cows and goats and sheep, and a place where seed-eating birds chirp and jump and eat, so the sea grass beds of the nearshore waters provide a grazing area for numerous creatures. Producing their food from direct interactions with the sun, these flowering underwater plants flourish and provide a food supply for various life forms.
Grazing in these grasses are tiny snails that cling to their leaves and spectacular conchs such as the Roostertails, the Tritons and the beautiful Queen Conchs. Prickly sea urchins like the Slate-Pencil Urchin can be found here or the edible West Indian Sea Egg. Flat sand dollars often feed here too along with grub-like looking sea cucumbers. Some star fish will be among the feeders.
But perhaps the most welcome visitors are those
mysterious migrants, the sea turtles, who are known to traverse the oceans
of the earth repeatedly, throughout their long lifetimes but choose these
shallow beds of turtle grass, as one of their favoured places to feed.
jellyfish, another favourite turtle food, may sometimes float into these
areas, providing an extra treat. Altogether, these sea grass beds with
their inhabitants, form yet another critical habitat linked to the ocean.
The kingdom where coral reigns
The Caribbean Sea, is seen by biologists, as a virtual desert, when compared to the seas and oceans of more temperate countries. The clear blue waters and white sands are tell-tale signs of low productivity when compared to dark coloured waters of other seas with rich biodiversity. But coral reefs are the exception. Here in these spectacular underwater domains, live thousands of creatures, in an intricate web of life.
In terms of structure, reefs may be one of three varieties. Fringing reefs, run adjacent to the shore. These can be seen at Speyside, Tobago or off Virgin Gorda, British Virgin islands. Barrier reefs form further offshore, with a deep lagoon between the sea and land. The Great Australian Barrier reef is the largest of its kind in the world, but in our own region the spectacular reef off Belize, provides an outstanding example. Buccoo Reef in Tobago is also a barrier reef. Other reefs may form independently of any mainland area, typically on a raised underwater "mountain" and breaking the surface to form a near circular coral formation. Such reefs are known as atolls and are common in the Polynesian islands of the South Pacific as well as East Indian Ocean islands such as the Maldives.
Whatever their structure, they are all equally fragile. It is thought that reef building creatures called coral polyps have taken centuries if not millennia, to build reefs the size we see today. Varieties of corals grow in differing areas of the reef, for instance the tall Elkhorn corals on the deep ocean-side reef walls and the hugemounds of brain corals on the shore-side sea bed. Some, like the finger corals, even colonise shallow inter-tidal pools on rocky seaside cliffs. A dazzling array of corals can be found, for instance, the many types of star corals. Getting to know and name the coral types is a challenge in itself.
The reefs are a scene of never ending colour, movement and life. Myriads of species swim and snoop and graze throughout the day and at night a different bevy of creatures come out to forage for food. like mangrove swamps, coral reefs also provide a nursery function for some creatures, including many species of commercially harvested fish and shell fish. like mangroves too, they protect the shoreline, particularly from huge ocean swells associated with hurricanes, as well as the erosion of day to day high tides. Here the action between predator and prey is stealthy and swift and all is done with blazing colour and intriguing camouflage.
Parrotfish nibble at the reef itself, processing tiny bits of coral and passingthem out as sand. They come in a variety of bright colours and have sharp teeth that seem to be fixed in a permanent neat smile. Other toothy reef creatures are the varieties of moray eels that lurk in their crevices and shoot out a sharp mouth to snatch the unsuspecting passerby. At night these reefs are often cruised by sharp-toothed barracuda. Several other reef fishes sport an amazing array of spots and bands and daubs all of bright colours. The tinier creatures of the reefs are by no means to be outdone with their brilliant markings. Sea stars and sea whips, sea eggs and conchs, may also travel between sea grass beds and the reefs. Sponges of spectacular shapes, sizes and colours and swaying sea fans, gently moving tube worms and many tentacled anemones, root themselves at points on the reefs floor or in other niches.
Dwellers from the wider ocean come to visit, often
in search of food. Grouper and snapper may seek out smaller fishes here
to eat. Sharks may also come searching. Some larger creatures such as the
friendly Manta Rays may stay permanently close to the reefs, as they do
at Speyside, Tobago, if the habitat remains healthy and they are left unharmed.
For human visitors, the reef provides a place to fish for food but also
to relax and enjoy its beauty, find pleasure in boating, swimming, diving
or snorkeling and generally to refresh the soul.
Fewer creatures inhabit the wide oceanic realms.
Here where the waters are deep, seagrasses cannot take root, for they could
not get light enough to grow at such depths. instead the dinoflagellates,
provide the ocean's free floating "sea meadows". Some fishes complete their
life cycles here, including the "pelagics" that swim near the surface like
dolphinfish and flying fish and the "demersals" like red fish, snapper
and grouper that feed nearer to the sea floor.
Living as well as non-living forms are found in
the graded margins that go from half exposed beaches to the often unseen
darkest depths of the ocean. Many of these zones have been given intriguing
names from Greek mythology including the neretic, bathyl, abyssal and hadal
realms. Each of these areas is now known to support life - some in ways
previously thought to be impossible.
Tell the life story
Choose a habitat in your area for exploration from the list described- Mangroves, Sea Grass Beds and Coral Reefs.
Coastal zone managers and conservationists in many islands and on mainland coasts, are beginning to identify special nearshore areas that they want to preserve.
While much is now known of our living resources especially in the areas close to land and in shallow sea beds, a world awaits to be discovered, at the deepest bottom of the sea. Careers in the 21 st century may well take workers to live for extended periods on the deep sea bed.