Oceanic Zone
The oceanic zone is an area of the open sea ecosystem with a depth that cannot be penetrated by sunlight to the bottom so that the bottom is very dark. In this oceanic zone, the water on the surface cannot mix with the water underneath because there is a difference in temperature.
Water layer boundary
The boundary of the two water layers is the thermocline area where fish schools are generally found. All areas under the eupphotic zones that can still be penetrated by sunlight include the batipelagic, abisal, pelagic, and hadal zones (Nontji 1987). The deep sea is the part of the marine environment that is located in the open ocean and is deeper than the continental shelf (> 200 m). Many communities in Indonesia's deep sea ecosystem are not known in detail.
This is due to the limited number of experts and technological devices they have to conduct research until it reaches deep water. In general, the diversity of species in deep sea waters is not as high as in other ecosystems. The communities that exist are only consumers and decomposers, there are no producers because sunlight cannot penetrate this area.
Consumer food comes from plankton that settles and other biota that has died. Thus, in the deep sea, prey and prey events occur. Fauna that live in oceanic deep water have a pale color and have beautiful eyes that are sensitive and give off light.
The mineral cycle occurs due to the movement of water from the coast to the middle of the sea in the upper layer. This displacement of water is replaced by water from areas that are not exposed to light, resulting in water displacement from the lower layers to the top (Kistinnah & Lestari 2009). The condition of the deep sea oceanic environment is very dark and it is certain that there is almost no photosynthesis process.
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| The organisms that live in these oceanic waters are very powerful organisms because they can survive with very minimal oxygen levels, high hydrostatic pressure, low water temperatures, and dark environments. Some recorded examples of deep sea fauna (depth> 200 m) in Indonesia are presented in the Table. |
Table: Some Deep Sea Fauna in Indonesia
|
Group |
Scientific
Name |
Local
Name |
Common
Name |
|
Fish |
Latimeria chalumnae |
Raja Laut (Sea king) |
Coelacanth |
|
Molluscs |
Tridacna gigas |
Kima Raksasa (Giant clams) |
Great clams |
|
Crustacean |
Paguristes antennarius and P. aciculus |
Kelomang |
Hermitcrab |
|
Coral |
Antiphates spp. |
Bahar roots |
|