Marine Habitats

Estuaries Definition: fresh water from a river mixes with salt water from the ocean -Transition area from the land to the ocean Other names: bay, sound, lagoon, harbor, bayou Ocean Area where fresh and salt water mix River bringing freshwater to the sea

Characteristics of Estuaries Water is brackish: a mixture of freshwater and saltwater There is a gradient (gradual change) in the salinity

Characteristics: Estuaries -Very nutrient rich ecosystems  leads to high productivity and high biodiversity -Fast-moving rivers and waves carry nutrient-rich particles -Sediment settles and accumulates -Great place for plants to grow!

-Buffers land from hurricanes, absorb storm surge

Estuary Have a large variety of species. eelgrass cordgrass glasswort – a succulent

Estuary animals Including… horseshoe crabs Mosquito…

Estuary animals oysters lobster

Estuary animals Flounder Striped Bass

Estuary animals Many, many birds! Common tern Great White Egret

Estuary animals Manatee

Estuary animals Sea lions at Pier 39 in San Francisco Bay

Salt Marshes -Low area that is subject to regular, but gentle, tides -Dominated by grasses (no trees or shrubs) Location: Gulf of Mexico and Atlantic coast Texas salt marsh

Alabama salt marsh Dauphin Island, AL

Mangrove Swamps -Coastal wetlands located in tropical and subtropical zones -Characterized by salt-tolerant trees and shrubs, such as mangrove trees

Mangroves

Rocky shores -Also called rocky intertidal zone – many places to live in this habitat, means high biodiversity -Organisms must be adapted to wave action, changing tide levels

Rocky Shores At low tides, there are often tide pools left behind where you can see starfish, anemones, crabs, octopus

Sandy shores

Sandy Shores Not as much biodiversity as rocky shores – Why? not much habitat diversity sand dries out at low tide some small things can live in the sand, food for shorebirds

Barrier Islands -Narrow islands made of sand that provide a buffer for the mainland from the sea -Constantly shifting, especially with storms Ex: Dauphin Island, Alabama

Barrier Islands Ocean Beach Intensive recreation, no building Primary Dune No direct passage or building Trough Limited recreation and walkways Secondary Dune No direct passage or building Back Dune Most suitable for development Bay or Lagoon Intensive recreation Bay shore No filling Grasses or shrubs Taller shrubs Taller shrubs and trees Think about ecological succession as you move away from the ocean. What is the “disturbance” in this ecosystem?

Notice the beach erosion. Barrier islands are constantly changing.

Coral Reefs Structures in the shallow oceans that are built by animals called corals Serve a habitat for many diverse organisms Require two things: warm temperatures and sunlight Found between 30°N and 30°S of the equator

Coral Reefs Corals are animals Coral polyps resemble small sea anemones with tentacles that can sting and paralyze prey

Coral Reefs -They build limestone houses that build up to form a reef. Polyps in limestone skeleton Elkhorn coral

Coral Reefs -Corals live in a symbiotic relationship with algae called zooxanthellae; -The algae are photosynthetic and give the coral food and oxygen -The algae get carbon dioxide and nutrients from the nitrogenous wastes of the coral

Coral Reefs There are many different kinds of corals: Soft corals Hard corals

Coral Reefs Growing on the reef with the corals are other animals, such as sponges, worms, shrimps, crabs, mollusks Living in and around the reef are fish, sea turtles, sea snakes, marine mammals

Coral Reef Destruction Coral bleaching – when temperatures go above normal, the zooxanthellae can’t thrive, the coral turns a whitish color and dies Natural causes: El Nino Manmade causes: Global warming

Coral Reef Destruction 2. Physical damage Ships, anchors, tourist divers Dynamite fishing - reefs are damaged by physical destruction that may occur when people collect fish

Coral Reef Destruction Land development and pollution – loss of mangrove forests means more nutrients and sediments flow out to the sea; coral may die from sediment or algal blooms Fish and coral trade Increased exposure to UV due to ozone depletion

Hydrothermal Vents (review) -Water sinks into fissures. -Releases some nutrients and dissovles others. -Nutrients are used to support life on the ocean floor.

Kelp Forest Kelp is large brown algae (Seaweed) Provides rich habitat for species Will grow as deep as photosynthesis reaches.

Kelp Forest Kelp are found in nutrient rich and cold water. Found on the western coast of continents due to polar currents and upwelling of nutrients.