Marine biochemistry is not confined to organic chemistry but is also concerned with inorganic elements involved in life processes, which includes study of bioaccumulation of specific elements such as heavy metals and other pollutants. They also examine the processes that release CO2 from the oceans back into the atmosphere. The fate of substances produced by photosynthesis is also an important field of investigation. Although photosynthesis does not occur below depths of about 100 metres because of insufficient light, organic production is still considerable in deep water because of the utilisation of dissolved organic matter, mainly by bacteria. This dissolved organic material mostly derives from photosynthesis in surface waters but in special cases can also arise from deep-sea hydrothermal vents.
Marine biochemists study the nature of all life process chemicals in the oceans.
The advent of mariculture, the farming of plants and animals in sea water, poses diverse challenges to biochemists. Examples include the development of attractive food formulations to optimise production, and determining the molecular biochemistry associated with the manipulation of genes for expression of desirable characteristics, for example a particular colour, increased growth, or disease resistance. Another important field is biogeochemistry. This includes study of the biological and chemical processes involved in the transport of material through the water column to the sediment, its long term storage and modification in the sediment, and whether and how it is subsequently released. Marine biochemists also study the effects of human activities, including increasing nutrient and sediment loadings in the oceans.