Ecosystem is an ecological system formed by the reciprocal relationship between living things and their environment. One of the obstacles in determining ecosystem types is the difficulty in determining clear boundaries of a system. A hierarchical order is obtained by placing the smaller ecosystems sequentially within the larger ecosystem, that is, starting with the biosphere to the next lower level.
The biosphere is the largest ecosystem, namely the outer shell of the planet Earth which is a medium for the life of various organisms. Based on anthropogenic factors, the biosphere is divided into two main groups, namely natural ecosystems and artificial ecosystems.
Natural Ecosystem
Ecosystems that are formed naturally without human intervention are called natural ecosystems. The function of this ecosystem is directly dependent on the sun as an energy source. Based on common life media such as water, soil and air, natural ecosystems are divided into marine ecosystems, limnic eco., semiterrestrial eco., and terrestrial ecosystms (Ellenberg 1973).
Marine Ecosystem (Brine)
The marine ecosystem is a unit consisting of various organisms that function together in a collection of brine masses in a certain area, both dynamic and static, allowing the flow of energy and the cycle of matter between biotic and abiotic components. As a maritime country, Indonesia has a wider medium of life in the form of brine (sea) (70%) compared to the total area of its terrestrial media (30%).
Large marines waters have different zones, both horizontally and vertically (Figure) which creates a variety of environmental conditions so as to create a diversity of ecosystems in a smaller hierarchy. Horizontally, there are two areas of the marine ecosystem, namely neritic and oceanic, which when combined vertically, each is further divided into several zones, namely epipelagic, mesopelagic, batipelagic, abisopelagic, and hadal.
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| Horizontal and vertical division of zoning in marine waters |
Epipelagic features include neritic or oceanic areas that are still at a depth of up to 200 m and can be penetrated by sunlight. The most saltwater biota can be found in this zone. Mesopelagic mints are at a depth of 200–1,000 m with minimum light presence. The batipelagic zone is at a depth of 1,000–4,000 m, the abisopelagic area is 4,000–6,000 m, and the hadal zone is at a depth of more than 6,000 m.
Mintakat Neritik
The neritic patch stretches from the shore that is reached by the highest tide to the sea with the bottom part that can still be penetrated by sunlight (sublitoral base). Mintakat neritik is known as the nearshore area, located along the shallow coast with a width of 16–240 km.
This Mintakat is divided into two, namely intertidal and subtidal. Intertidal is the tidal area located on the littoral base, which is the part of the coast that is bounded by the highest and lowest tides.
Meanwhile, subtidal is the part of the water that is bounded by the coast which experiences the lowest recess to the high seas with a depth of about 200 m and is also known as shallow sea. The communities in the neritic zone are located along the coast which is always inundated at the lowest tide, include open coasts that are not affected by large rivers or are located between steep rock walls.
This community is generally dominated by various types of algae, seaweed (Kistinnah & Lestari 2009), plankton, nekton, neston, and benthos. At least, there are two types of ecosystems in this area, namely coral reefs and seagrass beds.