Marine Ecosystem and Tidal Processes

Marine Ecosystem Structure

• Marine ecosystems are complex communities of organisms interacting with their physical environment, including water salinity, temperature, and light penetration.
• These ecosystems are diverse, encompassing zones from the intertidal zone to the deep sea.
• Different zones support unique species adapted to specific environmental conditions.
• Major marine ecosystems include estuaries, coral reefs, kelp forests, mangroves, seagrass beds, and the open ocean (pelagic and benthic zones).

Tidal Processes

• Tidal forces are primarily caused by the gravitational pull of the moon and sun on Earth's oceans.
• Gravitational forces create bulges of water (high tides) on the sides of Earth facing and opposite the moon.
• Earth's rotation relative to these bulges results in the periodic rise and fall of sea levels.
• Tidal cycles typically have two high tides and two low tides per 24 hours and 50 minutes, an approximate time period. This is because Earth rotates slightly slower than the moon's orbit.

Intertidal Zone

• The intertidal zone is the area between high and low tide marks.
• Organisms in this zone face repeated cycles of submersion and exposure.
• Organisms must adapt to varying salinity, temperature, and desiccation (drying out).
• Characteristic organisms include barnacles, mussels, limpets, seaweed, and sea stars.
• These species have adaptations like shells, strong holdfasts, and water retention mechanisms to manage environmental stresses.

Estuaries

• Estuaries are partly enclosed coastal bodies of water where freshwater from rivers meets the ocean.
• They have variable salinity, a mix of saltwater and freshwater.
• The mixing zone supports a unique mix of marine and freshwater species.
• Fish, shellfish, and waterfowl use estuaries as nurseries and feeding grounds.
• Estuaries are highly productive ecosystems, vital habitats for various species.

Coral Reefs

• Coral reefs are formed by colonies of coral polyps.
• Coral reefs are among Earth's most diverse ecosystems.
• They provide habitat and food for a vast array of marine organisms.
• Coral polyps create a hard calcium carbonate skeleton forming the reef structure.
• Coral reefs flourish in shallow, clear, and warm waters. Reef-building corals require sunlight for their symbiotic algae to photosynthesize.

Kelp Forests

• Kelp forests are underwater ecosystems dominated by large brown algae called kelp.
• They are characterized by tall kelp plants forming dense underwater forests.
• Kelp forests provide vital habitat and food for a wide variety of marine species.
• Kelp forests are highly productive and often occur in cool, nutrient-rich waters.
• Invertebrates and fish rely on these forests as homes and feeding grounds.

Mangroves

• Mangroves are trees that grow in coastal saline or brackish waters.
• Mangroves provide critical coastal protection acting as natural defenses against storms and erosion.
• Mangroves support abundant marine life.
• They are crucial nursery areas for many fish and shellfish species.
• These forests stabilize soil and prevent coastal flooding.

Coastal Ecology

• Tidal processes are significant drivers of coastal ecology.
• The periodic influx and withdrawal of seawater causes dynamic changes in salinity, oxygen levels, nutrient availability, and species distribution.
• These changes affect the structure and function of coastal ecosystems.
• Tidal processes influence food webs and species distribution.
• Coastal ecosystems are sensitive to changes in tidal rhythms and sea levels, such as those related to climate change.

Impact of Human Activities

• Human activities like pollution, coastal development, and climate change are impacting marine ecosystems.
• Habitat degradation diminishes the resilience and integrity of coastal ecosystems.
• Climate change impacts temperatures, salinity, and storm patterns, harming and disrupting marine species, especially in the intertidal zone.
• Overfishing, pollution, and other human activities greatly alter these delicate marine environments.