Marine Ecosystem

Summary

In this lecture, Dr. Sochi Nandata provides an in-depth overview of the marine ecosystem, covering the ocean's structure, including the pelagic and benthic provinces, and the various zones within them. He explains the diversity of marine ecosystems, such as rocky shores, sandy beaches, and coral reefs, highlighting their unique characteristics and ecological importance. The video also addresses the food web in the ocean, the services marine ecosystems provide, including climate regulation, nutrient cycling, and economic contributions. Finally, Dr. Nandata discusses the threats facing the marine ecosystem, including over-exploitation, pollution, and climate change.

Takeaways

• 😀 The ocean is divided into two main provinces: the pelagic zone (open ocean) and the benthic zone (seafloor).
• 😀 The pelagic zone is further divided into sub-zones based on depth: epipelagic (0-200m), mesopelagic (200-2000m), bathypelagic (1000-2000m), abyssal pelagic (2000-6000m), and hadalpelagic (beyond 6000m).
• 😀 The benthic province includes sub-regions like the littoral zone, continental slope, and abyssal zones, all based on depth.
• 😀 The ocean is categorized into three light zones: the photic zone (0-200m, light-penetrating), dysphotic zone (200-2000m, dim light), and aphotic zone (below 2000m, no light).
• 😀 Coastal ecosystems include diverse areas such as estuaries, salt marshes, mangroves, rocky shores, sandy shores, and coral reefs, all of which are highly productive.
• 😀 Coral reefs are one of the most diverse and productive ecosystems, supported by a symbiotic relationship between corals and zooxanthellae algae.
• 😀 Rocky shore ecosystems are dynamic, influenced by tidal cycles and featuring organisms like sea lettuce, barnacles, and sea urchins.
• 😀 Sandy shore ecosystems are stable, with organisms like crabs, moon snails, and ghost shrimp, adapted to burrow into the sand.
• 😀 Marine food webs are complex, with plankton serving as the base of the food chain, supporting various consumers from small fish to top predators like blue whales and tuna.
• 😀 Marine ecosystems provide essential services, including climate regulation, CO2 absorption, nutrient cycling, storm protection, biodiversity, and economic benefits like fisheries, tourism, and pharmaceuticals.

Q & A

What are the two main divisions of the ocean's structure?

The ocean's structure is divided into two main provinces: the pelagic province and the benthic province.

What is the difference between the neritic and oceanic zones?

The neritic zone is located near the coast, while the oceanic zone refers to the area farther from the coast.

What are the different sub-zones of the pelagic province?

The pelagic province is divided into the epipelagic zone (0 to 200 meters), mesopelagic zone (200 to 2000 meters), bathypelagic zone (1000 to 2000 meters), abyssopelagic zone (2000 to 6000 meters), and hadalpelagic zone (beyond 6000 meters).

What are the major zones of the benthic province based on depth?

The benthic province is divided into the littoral zone (continental shelf), continental slope, and abyssal zone, with the hadal zone beyond 6000 meters.

What is the significance of the euphotic zone?

The euphotic zone, also known as the photic zone, extends to a depth of about 200 meters, where sunlight can penetrate. It is the most productive region of the ocean for photosynthesis.

What are the types of coastal ecosystems mentioned in the script?

The coastal ecosystems mentioned include estuaries, salt marshes, mangroves, rocky shores, sandy shores, and coral reefs.

Why are coral reef ecosystems considered highly productive?

Coral reefs are considered highly productive due to the symbiotic relationship between corals and algae, which provides a rich source of food and shelter for diverse marine species.

What are the main organisms found in the rocky shore ecosystem?

In the rocky shore ecosystem, you can find organisms such as sea lettuce, kelp, barnacles, mussels, sea urchins, hermit crabs, and sword crabs.

How do sandy shore ecosystems differ from rocky shore ecosystems?

Sandy shore ecosystems are more stable, as they absorb the energy of tides and waves, whereas rocky shores are more dynamic and experience greater variation in light and tidal conditions.

What are the primary threats to marine ecosystems?

The primary threats to marine ecosystems include overexploitation of marine resources, habitat degradation, pollution (such as oil spills), coastal erosion, and climate change, including rising ocean temperatures and ocean acidification.