Marine ecosystems

World's Five Oceans

The five oceans are the Arctic, Atlantic, Pacific, Indian, and Southern.

Ocean Depth Zones

The zones in the open ocean include the epipelagic, mesopelagic, bathypelagic, abyssopelagic, and benthic zones.

Importance of Oceans

Oceans act as carbon sinks, sources of oxygen, buffer temperature extremes, and control global climate.

Conditions for Coral Reef Formation

Tropical coral reefs require abundant light, warm temperatures, clear water, stable salinity, and low nutrient levels.

Types of Coral Reefs

The four types are fringing, barrier, patch, and atoll reefs.

Corals

Corals are animals belonging to the phylum Cnidaria, forming sessile colonies of polyps.

Hard Corals vs. Soft Corals

Hard corals are characterized by calcification, while soft corals lack this structure.

Coral Polyp Structure

A typical coral polyp has tentacles, nematocysts, mouth, stomach, calyx, theca, and basal plate.

Coral Nutrition

Corals obtain nutrition through capturing small organisms and their relationship with zooxanthellae.

Importance of Coral Reefs

Coral reefs are vital for tourism, food, coastal protection, medicines, and biodiversity.

Causes of Reef Erosion

Reef erosion can be caused by pH change, temperature extremes, predation, physical damage, and pollution.

Artificial Reefs

Artificial reefs provide substrates for reef communities and enhance biodiversity.

Rocky Shore Zones

Zones on a rocky shore include the splash zone, upper shore, middle shore, lower shore, and subtidal zone.

Biotic vs. Abiotic Interactions

Biotic factors are significant lower on the shore, while abiotic factors influence species higher up.

Sandy Shore Ecosystem

Sandy shores have an unstable substrate and fluctuating abiotic factors, leading to lower biodiversity.

Mangrove Forests

Mangrove forests are tidal ecosystems with salt-tolerant trees that influence biodiversity.

Red Mangrove Adaptations

Red mangrove has prop roots, salt-excluding roots, and viviparous reproduction.

Ecological Importance of Mangrove Forests

Mangroves provide nursery areas, trap sediments, stabilize tides, and protect coastlines.

Threats to Mangroves

Threats include temperature change, over-harvesting, storm damage, and coastal land use changes.