In general, open sea has a stable and very low nutrient load. But, nearshore water shows variations in nutrient load due to the addition of nutrients from domestic and industrial wastewaters.
Inorganic nutrients particularly, nitrogen and phosphorus, may limit algal growth. However, the presences of these nutrients in large quantities often lead to excessive growth of algae, a condition known as eutrophication.
Heavy metals like mercury have an inhibitory effect on microorganisms. However, certain microorganisms have developed resistance towards these heavy metals.
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