Final answer:
Nekton are oceanic zone swimmers capable of independent movement and include species such as fish and whales. The oceanic zone, less productive than coastal regions, relies on plankton as the basis of its food web. Nutrient-rich dead organic matter from the photic zone supports life in the deeper benthic zone.
Step-by-step explanation:
Swimmers that live in the open-ocean zones are known as nekton. These are aquatic animals that can move independently rather than drifting with the current. Nektonic organisms may inhabit both the photic zone, where there is enough light for photosynthesis, and the aphotic zone, where light does not penetrate. Examples of nekton include various types of fish, whales, and shrimp.
The open ocean, or oceanic zone, supports a web of life that begins with plankton—tiny organisms such as phytoplankton and zooplankton that serve as the foundation of the marine food chain. Despite being less productive than coastal areas like the neritic zone, the oceanic zone provides a habitat for large marine animals and is essential for global biodiversity.
The photic zone is rich in nutrients and supports a diversity of life due to photosynthetic organisms like phytoplankton. The deeper benthic zone contains organisms that survive on nutrients from dead organisms that fall from the upper layers, including a variety of sea cucumbers and other echinoderms. These organisms rely on material sinking from the more productive photic zone above, as the open ocean lacks significant nutrient recycling mechanisms.