Chapter 7-2 Marine Ecosystems

Marine ecosystems Coastal areas – Open ocean -

Coastal Wetlands Areas that are covered by salt water for all or part of the time are known as coastal wetlands. Provide habitat and nesting areas for many fish and wildlife.

Coastal Wetlands

ESTUARIES Estuary: an area where fresh water from rivers mixes with salt water from the ocean.

ESTUARIES

Plants and Animals of Estuaries High primary productivity supports many consumers Large populations of rooted plants as well as plankton. Plankton provide food for fish - can then be eaten by larger animals such as dolphins, sharks, etc. Oysters and clams anchored to rocks filter feeding

Plants and Animals of Estuaries Organisms must be able to tolerate variations in salinity Daily tides and river flow

Estuaries in populated areas were often used as places to dump waste. Threats to estuaries Estuaries in populated areas were often used as places to dump waste. Estuaries filled with waste could then be used as building sites. Pollutants such as raw sewage, pesticides, fertilizers, and toxic chemicals.

Salt marshes Salt marshes: found primarily throughout the temperate and subarctic regions.

Salt marshes Supports a community of clams, fish, aquatic birds, crabs, and shrimp. Can absorb pollutants and storm surges to help protect inland areas.

Mangrove Swamps Mangrove swamps:

Mangrove Swamps Protect the coastline from erosion and reduce the damage from storms. Provide a home and breeding area for about 2,000 animal species. Have been filled with waste and destroyed for coastal development in many parts of the world.

Rocky and Sandy Shores Rocky shores have many more plants and animals than sandy shores do Sandy shores dry out when the tide goes out

Rocky and Sandy Shores Barrier island:

Coral Reefs Coral reefs form in clear, warm coastal waters in tropical areas Tiny animals (polyps) and algae have a mutualistic relationship Polyps secrete calcium carbonate shells, which become coral reefs

Coral Reefs Thousands of species of plants and animals live in the cracks and crevices of coral reefs – one of the most diverse ecosystems on Earth. Corals are predators that use stinging tentacles to capture small animals, such as zooplankton, that float or swim close to the reef.

Coral Reefs

Coral Reefs

Coral Reefs Vulnerable to damage Warmer ocean temperatures leading to coral bleaching Coral expels algae and thus the polyps can die Increasing ocean acidity Direct destruction – boating, fishing techniques (trawling) Deposition of Sediment Algal Blooms

Coral Reefs

Oceans Water absorbs light, so enough sunlight for photosynthesis penetrates only about 100 m into the ocean. Ocean’s life is concentrated in the shallow coastal waters where sunlight penetrates to the bottom and rivers wash nutrients from the land.

Plants and animals of the Ocean In the open ocean, phytoplankton grow only in areas where there is enough light and nutrients, resulting in one of the least productive of all ecosystems. Fish feed on the plankton as do marine mammals such as whales.

Three vertical zones of the open sea Euphotic zone (top zone) Bathyal zone (middle zone)

Three vertical zones of the open sea Abyssal zone Dark and cold NPP low in the open sea Except in upwelling areas

Euphotic Zone Bathyal Zone High tide Coastal Zone Open Sea Low tide Depth in meters Sea level Photosynthesis Euphotic Zone Estuarine Zone Continental shelf Bathyal Zone Twilight Water temperature drops rapidly between the euphotic zone and the abyssal zone in an area called the thermocline. Abyssal Zone Figure 8.6: This diagram illustrates the major life zones and vertical zones (not drawn to scale) in an ocean. Actual depths of zones may vary. Available light determines the euphotic, bathyal, and abyssal zones. Temperature zones also vary with depth, shown here by the red line. Question: How is an ocean like a rain forest? (Hint: see Figure 7-14, p. 157.) Darkness Water temperature (°C) Fig. 8-6, p. 171