Marine Sector Management of Space and Natural Resources

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1.3.1.5 Marine Sector

The seas play an mportant role n global carbon cycle. Almost half of the oxygen that we use comes from photosynthess n the seas. Smlarly wth the forest, n the sea there are carbon storage and release processes. The total carbon store n the ocean s about 50 tmes the amount that exsts n the atmosphere. As shown by Fgure 4, the exchange mechansm of the ocean s very dynamc so the ocean could store and release sgnicant amount of carbon. The carbon exchange value n the ocean s about 90 bllon ton per year released to the atmosphere and 92 bllon ton per year absorbed. The dfference, whch s about 2 – 3 bllon tons per year s the carbon stored n the marne bomass lvng n the surface. The carbon store n the ntermedate and deep sea amounts to 38,000 – 40,000 bllon tons. As a comparson, land vegetaton produces a carbon cycle of 60 bllon ton of carbon released to the atmosphere and 61 bllon ton of carbon absorbed see the followng Fgure 4. Figure 4 Carbon cycle on land, atmosphere and sea. 17 The marne carbon cycle s conducted through two mechansms, whch are physcs and bology bologcal pump. CO 2 gas n atmosphere enters the sea because there are dfferences between CO 2 partal pressure n the sea and n the atmosphere, and the capacty of the sea to dssolve ths substance. CO 2 gas n the ar s absorbed by saltwater and used by phytoplankton at the sea surface. The contrbuton of phytoplankton to global carbon absorpton s nearly 50. Through photosynthess and respraton, phytoplankton carres out carbon exchange durng the day and nght tme. Part of the CO 2 gas produced by phytoplankton s released back to the atmosphere and part of t s stored or transfer to deep sea or sedment of sea bottom. Besde phytoplankton, other marne bota also conducts carbon exchange, such as coral reef, sea grass and mangrove. In a smlar way to land vegetaton, phytoplankton has chlorophyll that can absorb the spectrum of solar radaton. In addton, solar energy s also absorbed by salt water that causes the varaton of sea surface temperature. Ths mechansm can be recorded by satellte. Through ths remote sensng technology, the amount of prmary producton and sea surface temperature can be calculated so the carbon lux can be estmated. Carbon lux estmaton should be supported by contnung observaton regardng the marne bota’s capablty to conduct bologcal pump and other factors that nluence the qualty of the marne envronment. Indonesa as an archpelagc state has 5.8 mllon km 2 marne area, wth potental coral reef area about 61,000 km 2 , sea grass of 30,000 km 2 and mangrove forest wth an area of 93,000 km 2 . Therefore, Indonesan seas have large potental to absorb carbon snk and release carbon carbon emtter. Clmate change can nluence ocean characterstcs such as ocean crculaton, marne bogeochemstry cycle and ecosystem dynamcs. These factors are mportant element n ocean carbon cycle. Today, 48 of carbon that s released by combuston of fossl fuel s absorbed by the sea. CO 2 gas concentratons are ncreasng, causng an ncrease of hydrogen on concentraton n the sea. The effect s ncreasng acdty of the sea that wll mpact the marne ecosystem, through the mass death of coral reef, for example, that wll degrade the Indonesan marne envronment. 18

1.3.2 Management of Energy