Overview of Pasi Island

2.2.2 Seagrass Ecosystem

Seagrass ecosystems are one of three major ecosystems in shallow water that very complex. This region is a considerable potential of marine resources because it has physical and ecological functions that very importance, with high levels of biodiversity, and there is in tropical waters. Because it has high productivity, the ecosystem has a very large directly role to the other sea dwellers. Ecological functions of sea grass beds are as feeding ground, nursery ground, and spawning ground. In addition, the sea grass is an important food source of some kinds of organisms Arifin 2001. Sea grass ecosystem has a very high organic productivity. According to Erftemeijer 1993 and Zieman 1968 in Tuwo 2002, that the productivity of seagrass ecosystems is 180-712 gcm 2 Kennish 1990 states that there are five reasons why sea grass is a habitat that groove by a variety of fauna which association in it, they are: year. In this ecosystem the various types of marine life such as fish, crustaceans, mollusks, echinoderm and worms, formed complexity food webs, also resulting in energy flow and material cycles. There are organisms that live in sea grass beds and a faithful visitor also. a. Seagrass are effectively increasing the surface area of seagrass substrate for epiphytic flora and fauna. b. Seagrass reducing wave and tidal action, so that at the bottom of the water becomes calm, so very good for some animalsfauna. c. Seagrass reducing the water movement, dissolved minerals, and easily dissolved organic particles, thereby becoming a source of particles as food for biota. d. Density of seagrass leaf protecting the seabed from the sun compared to areas that not covered by seagrass, and causing the dense of animal benthos. e. Condition of seagrass beds that are protected with high food supply make seagrass to be attracting for nekton juvenile and large sizes nekton. Initially, seagrass vegetation was considered has economic value that is not too important, but lately has found some active ingredients that derived from seagrass leaves. Furthermore, many different types of fish that have high economic value lives on seagrass ecosystems, such as Siganus spp, Lethrinus spp, Lutjanus spp, Epinephelus spp, etc. Tomascik et al. 1997. One of the main functions of seagrass beds is as a refuge or a terminable place of juveniles and adults, many of which are animals that have significant commercial and recreational value Arifin 2001. Seagrass is the type of plants that has high biological productivity. Ecologically, these angiosperm marine plants has benefits as a food source for invertebrates and vertebrates, sea cucumbers, fish Acanthuridae and Scaridae, turtles, ducks, geese. Kennish 1990 reported that seagrasses are associated with algae in Texas Cape became the primary nutrient source for shrimp and fish. There are more than 340 animals consume seagrass in the area. At least, there are invertebrates species that eat the leaves of seagrasses directly, the rest of it falls to the bottom became a source of detritus. The highly number of invertebrates and fish in seagrass areas due those biota using seagrass beds as breeding, foraging and breeding places Kennish 1990.

2.2.3 Mangroves Ecosystem

Mangrove ecosystem is a system in place of the natural life that reflects the reciprocal relationship between organisms with their environment and among organisms themselves, there is in coastal areas, affected by tides, and dominated by typical tree species or shrub and can grow in salted waterbrackish Santoso 2000. Mangrove ecosystem has significance due the ecological functions that can be viewed in terms of physics, chemistry and biology. Ecological functions in terms of physical aspects are 1 occurrence mechanism of the relationship between the components of mangrove ecosystems and the relationship among mangrove ecosystem with other ecosystems such as seagrass beds and coral reefs; 2 mangrove has the ability as wave damper, mud holder, and protector of coastal from erosion, tidal waves and hurricanes by an extensive root system, strong and sturdy; and 3 mangrove which growing in estuaries or wetlands can also serve to reduce flooding. The three of that function will be disappear with the demise of the mangrove forests through logging, transfer function or because of degradation.