Organic matter coral reefs

Meyer, J. L., and Schultz, E. T. (1985). Migration of haemulid fishes as a source of nutrients and organic matter on coral reefs. Limnol. Oceanogr. 30(1), 146—156. 

Suzuki, Y., Nakashima, N., Yoshida, K., Casareto, B., Taki, M., Hiraga, T., Okabayashi, T., Ito, H., and Yamada, K. (1995). The important role of organic matter cycling for the biological fixation of CO2 in coral reefs. Energy Convers. Manag. 36, 737—740. 

Tribble G. W. (1993) Organic matter oxidation and aragonite diageneses in a coral reef. J. Sediment. Petrol. 63, 523-527. 

Fig. 2.2 Schematic of fundamental biogeochemical reactions occurring in coral reef systems. POM stands for particulate organic matter. Different types of POM are denoted by the subscripts Alio (allochthonous), Mixed (autochthonous), All (autochthonous + allochthonous), Auto (solely autotrophic).

Coral reef communities have also demonstrated the ability to take up suspended planktonic organic matter as a source of new carbon (Glynn, 1973 Johannes Gerber, 1974 Ayukai, 1995 Sebens etal., 1997 Fabricius etal., 1998 Ribes etal, 1998 Yahel etal., 1998). Reported rates of particulate carbon uptake are low (<40 mmol Cm-2 day-1) compared to rates of gross primary production and community respiration (Table 2.2), and have been demonstrated to be an unimportant source of carbon for some hard and soft coral communities (Ribes, 1998 submitted). However, the uptake of particulate organic matter may be an important source of food for some specific reef communities (Fabricius etal., 1998). 

Coral reef frameworks are partially lithified carbonate structures on which reef communities grow. Pore-waters of reef frameworks are mostly anaerobic and contain elevated levels of dissolved nutrients (Skyring Chambers, 1976 Buddemeier Oberdorfer, 1983 Corredor Capone, 1985 Sansone, 1985 Sansone etal., 1990). This is a common feature of many coral reefs (Sansone etal., 1990), and a direct result of oxidation of organic matter (Sansone etal., 1990 Tribble etal., 1990). The subsequent production of carbonic acid from the oxidation of organic matter lowers pore-water pH and reduces the activity of the carbonate ion, thus facilitating in situ dissolution of carbonate (primarily aragonite) (Sansone etal., 1990 Tribble etal., 1990). 

In a situation of adequate DIG, the quantity and density of zooxanthellae have a direct influence on the stability of the coral reef ecosystem, which is in symbiosis with the coral. Zooxanthellae can produce organic matter and discharge O2 during the photosynthesis process. The majority of organic matter was excreted from coral and O2 was supplied to coral for respiration. Some organic matter was captured by coral as one food source. Some CO2 discharged from coral respiration combined with Ca + in seawater and constructed the coral skeleton. 

Morton B, Blackmore G (2001) South China Sea. Mar PoUut Bull 42(12) 1236-1263 Muscatine L, Porter JW (1977) Reef corals Mutualistic symbioses adapted to nutrient-poor environments. Bioscience 27(7) 454-460 Ni HG, Lu FH, Luo XL, Tian HY, Zeng EY (2008) Riverine inputs of total organic carbon and suspended particulate matter from the Pearl River delta to the coastal ocean off South China. Mar PoUut Bull 56(6) 1150-1157 Onstad GD, Canfield DE, Quay PD, Hedges JI (2000) Sources of particulate organic matter in rivers from the continental USA Lignin phenol and stable carbon isotope compositions. Geochim Cosmochim Acta 64(20) 3539-3546 Peng Z, Chen T, Nei B, Head MJ, He X, Zhou W (2003) Coral records as an indicator of winter monsoon intensity in the South China Sea. Quat Res 59(3) 285-292... 

Sediments on the surface of the Earth may form in several ways (1) by mere mechanical accumulation (via wind or water), such as gravel and sand deposits in a river or sand dunes in a desert (2) by chemical precipitation, such as salt and calcite precipitation in shallow seas and lakes and (3) by activity of organisms, such as carbonate accumulation in coral reefs or the accumulation of organic matter in swamps (coal precursor). Sediments are typically deposited in layers or beds called strata. When sediments become compacted and cemented together (a process known as lithification), they form sedimentary rocks. This compaction or lithification of sedimentary materials into stratified layers is probably the most significant feature of sedimentary rocks. 

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