What is a marine ecosystem?

A marine ecosystem is defined as a community of living organisms in the ocean interacting with their environment. This encompasses a vast range of habitats and species, including not only the aquatic life found in open water, coral reefs, and along coastlines, but also the physical and chemical components of the sea that support them. Marine ecosystems consist of diverse organisms such as fish, marine mammals, mollusks, algae, and microorganisms, all of which rely on each other and the ocean's resources for survival.

This definition is broad enough to include different types of marine environments, such as deep-sea ecosystems, tidal zones, and coral reefs, among others. Each of these environments supports unique communities of organisms that interact with each other and their surroundings, utilizing elements like sunlight, nutrients, and physical structures.

The other options do not accurately represent a marine ecosystem in its entirety. For example, a collection of terrestrial organisms pertains specifically to land environments and does not include any aquatic life. Describing a marine ecosystem solely as a system of coral reefs limits the scope of what marine ecosystems encompass, as not all marine life exists within coral reefs. Similarly, referencing a biome consisting of brackish water bodies excludes the broader categories of marine habitats found in the ocean. Therefore,