Marine Ecosystems

• Aquatic environments house diverse organisms adapted to their specific characteristics.
• Marine environments are found at or near oceans and seas.
• Marine life includes all life forms in oceans and seas.

Marine Ecosystem Types

• Intertidal zones like beaches and shores experience daily water level changes due to tides.
• The neritic zone, between the intertidal zone and open ocean, features shallow, sunlit, nutrient-rich waters.
• The oceanic zone is the open ocean beyond the continental shelf, with varying depths.

Marine environment layers

• The photic zone is the top layer receiving sunlight, up to roughly 200 meters.
• The aphotic zone lies below, where sunlight cannot penetrate.
• The benthic zone is the ocean floor, shallow near the shore and deep in open waters.
• Each zone has distinct characteristics impacting the organisms that live there.

Marine Water

• Marine waters are saltwater, with higher salt concentrations than freshwater.
• Over 97% of Earth's water is marine water.
• Marine organisms regulate internal ion balance due to high salt concentrations, producing concentrated urine to remove excess salt.
• Freshwater organisms produce dilute urine to conserve ions.

Marine Organisms

• Marine organisms include plankton, plants, algae, invertebrates, fish, mammals, and birds.

Plankton

• Plankton are organisms transported by water movement.
• Phytoplankton are photosynthetic plankton, serving as primary producers in areas where plants can't grow.
• Zooplankton are animal plankton.

Plants and Algae

• Marine plants and algae are common in neritic and intertidal habitats.
• Most marine environments are too deep for plant life due to lack of sunlight.
• Coastal plants are adapted to high ion concentrations.
• Kelp forests, formed by brown algae like kelp, provide complex habitats.
• Green and red algae are other types of marine algae.

Invertebrates

• Invertebrates are organisms without backbones.
• Marine invertebrates include crustaceans (crabs, shrimp, lobsters), mollusks (clams, snails, squid, octopi), cnidarians (sea squirts, jellyfish), corals, anemones, urchins, and starfish.

Fish

• Fish use gills to extract oxygen from the water.
• Some fish pump water over their gills, while others swim constantly.
• Fins are used for propulsion, and swim bladders help maintain buoyancy.
• Sharks and rays are cartilaginous fish that can detect electric impulses.
• Coral reefs support the most diverse fish populations due to abundant resources and habitat.

Mammals

• Marine mammals include dolphins, whales, otters, seals, and walruses.
• Many have excess fat for warmth and skin impervious to saltwater.

Birds

• Coastal areas are bird hotspots.
• Shorebirds with long bills and legs frequent beaches.
• Some birds such as albatrosses spend months flying over open waters without landing.