A marine algae called Emiliana huxleyi can overgrow, creating an algal bloom covering thousands of square kilometers of ocean. As a consequence, these blooms can be devastating to ocean aquatic life. Fortunately, viruses contribute to its life cycle by lysing Emiliana huxleyi, thereby releasing trapped algal and minerals back into the ocean ecosystem.

Carbon

Explanation:

Emiliana huxleyi is a coccolithophore, a eukaryotic unicellular alga that grows in the oceans of the world, from the tropic to the subarctic areas. It has an external calcite skeleton, which is equivalent to aproximately one thirth of the CaCO₃ marine production. Under favorable conditions, this species can overgrow producing blooms, which are giant aggregations that can cover several square kilometers. These blooms can seriously affect the aquatic ocean life on a global level by running out nutrients and forbidding sunlight to reach certain depth levels.

When these blooms are infected with a specific virus called EhV, their calcic carbonate exoskeletons explode dispersing particles in water and releasing carbon and minerals back to the oceans. EhV viruses act as a biological control for these blooms.                

some fungi obtain their nutrients from a living host (plant or animal) and are called most biotrophic fungi have fairly narrow host ranges—they are specialized on a limited called rhizomorphs that allow the fungus to grow from one tree to another. ascospores are formed inside a sac-like structure called an ascus. so your answer is a

estuaries are the partially enclosed coastal bodies of brackish water formed at the mouth of sea where river meets an ocean. it is a transition zone between river and sea water so estuaries are influenced to both marine environment such as tides, waves and to riverine such as flow of fresh water and sediments. the mixing of sea and fresh water provide high level of nutrients, making estuaries a high product habitats.

many estuaries suffers degradation from a variety of human activities like erosion from deforestation, overgrazing, overfishing, drainage and eutrophication.

so from the above statement answers will be

1. false as estuaries are formed due to both brackish and freshwater.

2.true, due to high productivity estuaries are breeding ground for many marine species.

3. direct and indirect activities of man that contribute to pollution and deposition of sediments.