Marine Ecosystems and Ecology

Marine Ecology and Ecosystems

• Marine Ecology: The study of relationships between marine organisms and their interactions with the environment.
• Ecosystem: A physically distinct area containing abiotic conditions and a community of interacting species.
• Examples: Intertidal (Splash zone), Coral Reef, and Beach.

Continental Margin Structure

• Continental Margin: The submerged area of continents consisting of three parts:     - Continental Shelf: Flat, gradually sloping area from shoreline to $\sim 200\,m$; ends at the Shelf Break.     - Continental Slope: Steeply sloping area seaward of the shelf break.     - Continental Rise: Moderately sloping area seaward of the slope.

Pelagic and Benthic Zones

• Pelagic Zone: Refers to the water column.     - Nekton: Organisms that swim through the water (e.g., sharks).
• Benthic Zone: Refers to the ocean floor.     - Benthos: Organisms living on or in the seafloor (e.g., crabs).

Depth and Seafloor Divisions

• Pelagic Divisions (Vertical):     - Epipelagic: $0-200\,m$ depth.     - Mesopelagic: $200-1,000\,m$ depth.     - Bathypelagic: $1,000-4,000\,m$ depth.     - Abyssopelagic: $4,000-6,000\,m$ depth.     - Hadalpelagic: $6,000-10,000\,m$ depth.
• Benthic Divisions (Seafloor):     - Supralittoral: Shore above high tide.     - Littoral: Intertidal zone between high and low tide.     - Sublittoral: Seafloor of the continental shelf.     - Bathyl: Seafloor from continental slope to deep ocean bottom.     - Abyssal: Deep ocean bottom between the slope base and $6,000\,m$.     - Hadal: Deepest seafloor zones below $6,000\,m$.

Ecosystem Dynamics and Management

• Energy Transfer: Solar energy is converted by autotrophs, flowing through primary and secondary consumers.
• Ecosystem-based management (EBM): An integrated approach used by NOAA that considers entire ecosystem interactions rather than single species.
• Estuary: A highly productive ecosystem where freshwater from rivers mixes with seawater (e.g., Chesapeake Bay).