Photosynthesis marine

Consequences of Ozone Depletion. Ozone depletion over Antarctica is causing renewed concern about the consequences of increased levels of UV reaching the earth s biosphere. One area of concern involves the free-floating microscopic plants, known collectively as phytoplankton (the grass of the sea), which through the process of photosynthesis, fix carbon dioxide into living organic matter. Phytoplankton forms the basis of the marine food chain on which zooplankton (animal plankton) and all other components of the ecosystem depend for their sustenance. 

The annual primary production of organic carbon through photosynthesis is on the order of 70 Pg/yr. The major part of this carbon is decomposed or respired in a process that also involves the biogeochemical transformation of nitrogen, sulfur, and many other elements. Only a small part of the annual primary production of organic carbon escapes decomposition and is buried in marine sediments. On average. 

Oceanic surface waters are efficiently stripped of nutrients by phytoplankton. If phytoplankton biomass was not reconverted into simple dissolved nutrients, the entire marine water column would be depleted in nutrients and growth would stop. But as we saw from the carbon balance presented earlier, more than 90% of the primary productivity is released back to the water column as a reverse RKR equation. This reverse reaction is called remineralization and is due to respiration. An important point is that while production via photosynthesis can only occur in surface waters, the remineralization by heterotrophic organisms can occur over the entire water column and in the underlying sediments. 

Karsten U, Franklin LA, Liming K, Wiencke C (1998) Natural ultraviolet radiation and photosyn-thetically active radiation induce formation of mycosporine-like amino acids in the marine macroalga Chondrus crispus (Rhodophyta). Planta 205 257-262 Karsten U, Bischof K, Hanelt D, Tug H, Wiencke C (1999) The effect of ultraviolet radiation on photosynthesis and ultraviolet-absorbing substances in the endemic Arctic macroalga Devaleraea ramentacea (Rhodophyta). Physiol Plant 105 58-66 Kessler A, Baldwin IT (2002) Plant responses to insect herbivory the emerging molecular analysis. Ann Rev Plant Biol 53 299-328... 

Bischof K, Hanelt D, Wiencke C (2000) Effects of ultraviolet radiation on photosynthesis and related enzyme reactions of marine macroalgae. Planta 211 555-562... 

This equation describes the ratios with which inorganic nutrients dissolved in seawater are converted by photosynthesis into the biomass of "average marine plankton" and oxygen gas 02. The opposite of this reaction is respiration, or the remineralization process by which organic matter is enzymatically oxidized back to inorganic nutrients and water. The atomic ratios (stoichiometry) of this reaction were established by... 

Aliphatic hydrocarbons, a diverse suite of compounds, are an important lipid fraction which is either natural (i. e., from photosynthesis by marine biota inhabiting the surface waters or by terrestrial vascular plants) or anthropogenic (i. e., of petroleum origin from land runoff, and/or industrial inputs). Aliphatic hydrocarbons have been studied and characterized from various environmental multimedia [1,53-56,99-109]. 

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