You have probably seen pictures of the diverse communities flourishing in the dark depths around hydrothermal vents on the ocean floor. scientists were at first surprised to find that the vents support such thriving ecosystems, because in such an environment, you wouldn't think there could be very many:

c. Producers.

Explanation:

A hydrothermal source is a crack in the earth through which water flows, was heated under the surface by magma. Heat causes water to flow precipitously to the surface. If the crack is on the earth, it is called Geyser, and if it is underwater, it is called fumarole.

Producers are those organisms that synthesize organic matter from inorganic matter, in marine ecosystems marine plants are the primary producers.

For producers to acquire energy, sunlight is necessary, so it was considered impossible for producers to exist in deep waters in the oceans. However, around the fumaroles ecosystems have been found that subsist only with minerals that come from the expelled water, such as sulfur.

I hope this information can help you.