ESTUARINE ECOSYSTEM

ESTUARIES ARE BODIES OF WATER WHERE FRESH WATER IN FROM THE LAND MIXES WITH THE SALINE WATER OF THE SEA. THEY REPRESENT DYNAMIC COMBINATIONS OF FRESH WATER AND MARINE COMMUNITIES AND THEY HAVE A NUMBER OF UNIQUE CHARACTERISTICS. DUE TO THEIR HIGH NUTRIENT CONCENTRATIONS AND CHURNING ACTION, ESTUARIES  ARE EXTREMELY PRODUCTIVE AND QUITE RICH IN PLANKTONS, CRABS, CLAMS, OYSTERS, AND FISH.

CHILIKA ESTUARY VIEW IN THE MORNING TO THE LEFT AND THE SUNSET VIEW IN THE RIGHT.

ESTUARIES ARE UNDER INCREASING PRESSURE FROM POLLUTION AND COMMERCIAL EXPLOITATION. IN MANY PARTS OF THE WORLD'S GREATEST CITIES, ESTUARINE SYSTEMS ARE FORCED TO SERVE MULTIPLE PURPOSES ARE WATERWAYS, DUMPING GROUNDS, COOLING WATERS FOR POWER PLANTS, COLLECTION BASIN FOR SURFACE EROSION AND RECREATIONAL AREAS FOR HUMANS. AS A RESULT MANY ESTUARIES HAVE LOST THEIR PRODUCTIVE BIOLOGICAL SYSTEM.

THE INCREASING INTENSITY OF POLLUTION IN ESTUARIES ARROUND THE WORLD IS AFFECTING VARIOUS LIVING ORGANISM AND ACTING AS A THREAT TO THEIR LIFE.

MARINE ECOSYSTEMS OR AQUATIC DIVERSITY BASICS

MARINE ECOSYSTEMS COVER MORE THAN 70 PERCENT OF THE EARTH'S SURFACE, WITH AN AVERAGE DEPTH OF 3750 M; MARINE ECOSYSTEMS ARE OF SINGULAR ECOLOGICAL SIGNIFICANCE. UNLIKE TERRESTRIAL AND FRESH WATER ECOSYSTEMS, THE SEA IS IN A CONTINUAL CIRCULATION.

THE MARINE ECOSYSTEM IS BEING DIVIDED INTO VARIOUS ZONES : -

THE DI-GRAMMATICAL REPRESENTATION OF VARIOUS ZONES OF MARINE ECOSYSTEM

LITTORAL ZONE  :  - THE LITTORAL ZONE IS THE SHORELINE BETWEEN THE LAND AND THE OPEN SEA. IT IS SUBJECT TO PHYSICAL VIOLENCE OF WAVES AND TIDES AND TO FLUCTUATIONS IN TEMPERATURE, MOISTURE AND LIGHT INTENSITY. ALGAE, BARNACLES, STARFISH, ETC., INHABIT THE ROCKY SHORES, WHILE GHOST CRABS, SAND DOLLARS, POLYCHAETES, INHABIT THE SANDY SHORES. MUD FLATS WHICH OCCUR IN BAYS ARE OCCUPIED BY HARBOUR ALGAE, CLAMS AND CRUSTACEA.

STAR FISH BELONGS TO AESTEROIDEA CLASS AND ECHINODERMATA PHYLUM. IT CAN SWALLOW A PREY BIGGER IN SIZE THAN ITS MOUTH.








THE GHOST CRABS ALSO KNOWN AS SAND CRABS BELONGS
TO MALACOSTRACA CLASS AND OCYPODE GENUS."THESE CRABS ARE CALLED 'GHOSTS' BECAUSE THEY ARE TRANSLUCENT, AND BECAUSE OF THEIR ABILITY TO DISAPPEAR FROM SIGHT ALMOST INSTANTLY, SCUTTLING AT SPEEDS UP TO 10 MILES PER HOUR, WHILE MAKING SHARP DIRECTIONAL CHANGES.




NERITIC ZONE : - THE NERITIC ZONE IS UNDERLAIN BY A CONTINENTAL SHELF, EXTENDING OUTWARD TO ITS EDGE ABOUT 200 METERS DEEP. IT IS A HIGHLY PRODUCTIVE ECOSYSTEM. THIS REGION ABOUNDS IN EXTENSIVE ALGAL COMMUNITIES, CLAMS, SNAILS, WORMS AND ECHINODERMS THAT DOMINATE THE BOTTOM.

PELAGIC ZONE : - THE PELAGIC ZONE IS THE OPEN SEA AND CONSTITUTES ABOUT 90 PERCENT OF THE TOTAL OCEAN SURFACE. PLANKTONIC DIATOMS AND DINOFLAGELLATES PRIMARILY OCCUPY THE SURFACE PELAGIC ZONE.

PLANKTONIC DIATOMS AND DINOFLAGELLATES OCCUR ALONG THE SURFACE. SHRIMPS, JELLYFISH, AND CTENOPHORES ARE ACTIVE SWIMMING FORMS. IN THE DEEP WATERS MANY FISH ARE BIOLUMINESCENT WHILE SOME HAVE LIGHT PRODUCING ORGANS.

BENTHIC ZONE : - THE BENTHIC ZONE EXTENDS FROM THE EDGE OF THE CONTINENTAL SHELF TO THE DEEPEST OCEAN TRENCHES. ORGANISMS HERE ARE HETEROTROPHIC, MANY BEING ANCHORED IN MUDDY OOZE MADE UP LARGELY OF SILICEOUS AND CALCAREOUS SHELVES OF SNAILS, DIATOMS. AMONG THE ROOTED SPECIES ARE SEA LILIES, SEA FANS, SPONGES,AND BRACHIOPODS. SNAILS, CLAMS ARE EMBEDDED IN THE MUD WHILE STARFISH, SEA CUCUMBERS AND SEA URCHINS MOVE ON ITS SURFACE.

 SEA URCHINS ARE SMALL, SPINY, GLOBULAR ANIMALS THAT BELONGS TO ECHINOIDEA.

SEA CUCUMBERS ARE ECHINODERMS FROM CLASS HOLOTHUROIDEA.

SEA SPONGES ARE ANIMALS OF THE PHYLUM PORIFERA. THEIR BODIES CONSISTS OF JELLY LIKE MESOHYL SANDWITCHED BETWEEN TWO THIN LAYERS OF CELLS.

PHOTIC  ZONE : - PHOTIC ZONE IS THE ZONE TILL WHICH THE SUNLIGHT REACHES INSIDE THE SEA SURFACE.

APHOTIC  ZONE : - APHOTIC ZONE IS AFTER THE PHOTIC ZONE IT EXTENDS UPTO THE DEPTH OF THE SEA. THE SUNLIGHT DOESNOT REACH THIS ZONE.

IMACT OF GLOBAL TRAWLING ON MARINE DIVERSITY

TRAWLING IS THE DRAGGING OF WEIGHTED NETS ACROSS THE SEA FLOOR TO CATCH SHRIMP AND BOTTOM DWELLING FISHES SUCH AS FLOUNDER. IT IS A MAJOR SOURCE OF PRESSURE ON THE BIODIVERSITY OF THE COASTAL ECOSYSTEM. MODERN TRAWLING DEPLETES TARGETED FISH STOCKS. WHAT IS WORSE, IT DAMAGES  OR DESTROYS NON TARGETED SPECIES, INCLUDING CORALS AND SPONGES THAT MAY TAKE YEAR TO RECOVER.

TRAWLING IS AN ENVIRONMENT CONCERN AS IT LACKS SELECTIVELY AND PHYSICALLY DAMAGES THE SEA LAND.

THE THICK NATURAL CARPET OF BOTTOM-DWELLING PLANTS AND ANIMALS IS IMPORTANT FOR THE SURVIVAL OF MANY FISH SPECIES. THUS, THE DESTRUCTION OF SEA FLOOR HABITATS IN HEAVILY TRAWLED AREAS LEADS TO THE DECLINE OF THE FISHING STOCKS.

MORE AND MORE TRAWLERS ARE MOVING BEYOND THE CONTINENTAL SHELF, EXPANDING INTO AREAS THAT PREVIOUSLY WERE NOT SWEPT BY TRAWLERS. DEEP-SEA SPECIES GROW MORE SLOWLY THAN SHALLOW WATER SPECIES. HENCE THE LONG TERM IMPACT OF THIS PRACTICE IS MAGNIFIED AS TRAWLING DEPTH INCREASES.

SOME MARINE ECOLOGISTS HAVE COMPARED THE IMPACT OF TRAWLING ON THE BIOLOGY OF THE SEAFLOOR TO THAT OF CLEAR-CUTTING ON FOREST ECOSYSTEMS.

THE TORTOISE ARE GETTING KILLED DUE TO THE TRAWLING.

VARIOUS UNDERWATER PLANT AND ANIMAL SPECIES ARE GETTING DAMAGED DUE TO THIS TRAWLING  AND MANY OF THEM ARE ALREADY BECOME EXTINCT.

SOME IMPORTANT TERMS OF BIODIVERSITY

* ABIOTIC COMPONENTS:-

THE NON-LIVING COMPONENTS OF AN ECOSYSTEM SUCH AS THE NATURAL RESOURCES AND THE ATMOSPHERIC CONDITIONS.

* BIOLOGICAL DIVERSITY OR BIODIVERSITY:-

THE VARIETY OF LIFE FORMS: THE DIFFERENT PLANTS, ANIMALS AND MICRO ORGANISMS, THE GENES THEY CONTAIN, AND THE ECOSYSTEM THEY FORM.

* BIOTIC COMPONENTS:-

THE LIVING COMPONENTS OF AN ECOSYSTEM.

* COMMUNITY:-

THE COLLECTION OF ALL THE INTERACTING POPULATIONS OF DIFFERENT  SPECIES EXISTING IN GEOGRAPHICAL AREA.

* ECOSYSTEM DIVERSITY:-

THE VARIETY OF HABITATS FOUND IN AN AREA.

* ECOSYSTEM:-

A COMMUNITY OF LIVING ORGANISMS (POPULATIONS OF SPECIES)  INTERACTING WITH ONE ANOTHER AND WITH ITS NON-LIVING PHYSICAL AND CHEMICAL ENVIRONMENT.

* FAUNA:-

ALL THE ANIMALS LIVING IN AN AREA.

* FLORA:-
ALL THE PLANTS OF A PARTICULAR AREA.
* GENETIC DIVE5RSITY:-
THE VARIETY IN THE GENETIC MAKE UP AMONG INDIVIDUALS WITHIN A SPECIES.
* HABITAT:-
THE PLACE OR TYPE OF SITE WHERE AN ORGANISM NATURALLY OCCURS.
* INTRINSIC VALUE OF DIVERSITY:-
VALUE BASED ON THE VIEW THAT BIODIVERSITY IS WORTH PROTECTING FOR ITS OWN SAKE REGARDLESS OF ITS VALUE TO HUMANS.
* INSTRUMENTAL VALUE OF BIO-DIVERSITY:-
THE VALUE OF BIODIVERSITY ARISING FROM ITS USEFULNESS TO HUMAN BEINGS.
* MICRONUTRIENTS: -
 ESSENTIAL ELEMENTS WHICH LIVING ORGANISMS (INCLUDING HUMAN BODIES AND PLANTS) NEED IN VERY LOW CONCENTRATIONS FOR NORMAL GROWTH.
* POPULATION:-
THE MEMBERS OF A SPECIES LIVING AND INTERACTING WITHIN A SPECIFIC GEOGRAPHICAL REGION.
* SPECIES:- 
A GROUP OF ORGANISMS CAPABLE OF INTERBREEDING FREELY WITH EACH OTHER BUT NOT WITH MEMBERS OF OTHER SPECIES.
* SPECIES DIVERSITY: - 
THE NUMBER OF PLANT AND ANIMAL SPECIES PRESENT IN A COMMUNITY OR AN ECOSYSTEM .