These and other elements present are necessary for marine life forms to survive. Table salt will not suffice. Artificial 'marine salt' mixes will also contain as many as 70 trace elements found naturally in the oceans, some of which are essential ingredients. All gases that occur in the atmosphere are likely to be found in seawater, their concentrations dependant upon their solubilities, their chemical and biochemical reactions and the temperature and salinity of the water. Oxygen in the Marine Aquarium Nitrogen is important in aquarium conditions because of the introduction of nitrogenous material as food and conversion by the nitrifying bacteria, but is less important in the sea.
Carbon dioxide is highly soluble in seawater.
It will enter the water through the respiratory activities of fish, invertebrates, algae and bacteria. It will leave the water by atmospheric interchange at the surface, or by complex chemical reactions with other elements in the 'Carbon Cycle'. Living Animals and Plant Life. Real seawater contains masses of invisible planktonic life. In Spring the inland waters surrounding the British Isles may be coloured brown by naturally occurring blooms of phytoplankton.