GEOLOGY

Detailed explanation-1: -Most marine organisms live within the sunlit surface waters. Strong sunlight supports photosynthesis by marine algae. Algae either directly or indirectly provide food for the majority of organisms. All marine algae live near the surface because they need sunlight to survive.

Detailed explanation-2: -At the surface of the ocean, the euphotic zone, the ecosystem receives plenty of light and oxygen, is fairly warm, and supports many photosynthetic organisms. Many of the organisms that we associate with marine ecosystems, such as whales, dolphins, octopi, and sharks, live in the open ocean.

Detailed explanation-3: -The majority of this production is from oceanic plankton-drifting plants, algae, and some bacteria that can photosynthesize. One particular species, Prochlorococcus, is the smallest photosynthetic organism on Earth.

Detailed explanation-4: -Aquatic Plants and Photosynthesis During a sunny day, dissolved oxygen in water is generally plentiful because photosynthesizing algae and aquatic plants are constantly releasing it into the water. Even though many other organisms are using the oxygen, there is an oxygen surplus.

Detailed explanation-5: -This upper region is called the photic zone; almost all of the marine plants and tiny microscopic marine organisms that engage in photosynthesis can thrive only in the photic zone. Two hundred meters is a lot of ocean, right? Maybe, but the depth of the photic zone is only a tiny fraction of the ocean’s total depth.