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Shankar IAS Summary: Marine Organisms- 2 | Famous Books for UPSC Exam (Summary & Tests) PDF Download

Introduction

Marine organisms encompass a diverse array of life forms adapted to the unique challenges of life in the world's oceans and seas. From microscopic plankton drifting near the ocean's surface to majestic whales traversing its depths, marine life spans a vast spectrum of sizes, shapes, and ecological roles. These organisms play crucial roles in maintaining the health of marine ecosystems, contributing to processes like nutrient cycling, oxygen production, and the regulation of global climate.

Shankar IAS Summary: Marine Organisms- 2 | Famous Books for UPSC Exam (Summary & Tests)

Sea Grass

Sea grasses are marine flowering plants (angiosperms) with a grass-like appearance, producing flowers, strap-like or oval leaves, and a root system.

  • They thrive in shallow coastal waters with sandy or muddy bottoms, requiring relatively calm areas.
  • Unique as the only group of higher plants adapted to life in saltwater. 
  • Major sea grass meadows in India are found along the south-east coast of Tamil Nadu and in the lagoons of a few Lakshadweep Islands, with some grass beds around Andaman and Nicobar islands.
  • The abundant growth of seagrasses in Tamil Nadu and Lakshadweep is attributed to high salinity, water clarity, and sandy substrate.

Shankar IAS Summary: Marine Organisms- 2 | Famous Books for UPSC Exam (Summary & Tests)


Question for Shankar IAS Summary: Marine Organisms- 2
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What are the functions of sea grass beds?
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Functions of Sea Grass

  1. Sea grass beds physically help:
    • Reduce wave and current energy.
    • Filter suspended sediments from the water.
    • Stabilize bottom sediments to control erosion.
  2. Provide habitat for marine invertebrates and fishes.
  3. Enhance fish and migratory bird populations in lagoon areas by offering food and shelter.
  4. Act as nutrient sinks on reef flats and near estuaries, buffering or filtering nutrient and chemical inputs to the marine environment.

Do you know?

The five species of turtles nesting on the Indian coast are Leatherback sea turtle, Green turtle, Olive Ridley, Hawksbill, and Loggerhead turtle.

  • IUCN prioritizes the conservation of sea grass.
  • Out of 58 world species, fourteen seagrass species are recorded from the Indian coast.
  • Commonly distributed from inter-tidal to sub-tidal regions down to 8m depth.
  • Dugong, a mammal dependent on sea grass for food, is on the verge of extinction.

Threats to Sea Grass Beds

  • Environmental Threats

     Eutrophication, siltation, and coastal engineering harm seagrass beds. Eutrophication leads to algal blooms, siltation reduces sunlight penetration, and coastal constructions disrupt natural habitats.

  • Human-Induced Pressure
    Trawling and overexploitation for commerce directly threaten seagrass beds. Trawling damages habitats, while overexploitation depletes seagrass-dependent species, jeopardizing the health and sustainability of these ecosystems.

Management

  • Major seagrass beds should be mapped, and areas identified for preservation.
  • Dredging should be carried out away from grass beds to prevent siltation and turbidity, which can harm the beds.

Seaweeds

Seaweeds, macroscopic algae known as thalloid plants, lack true tissues like roots, stems, and leaves.

  • Larger, visible marine plants, seaweeds, are attached to rocks, corals, and other submerged surfaces in intertidal and shallow subtidal zones of the sea.
  • They thrive in shallow coastal waters wherever sizable substrata is available.
  • Seaweeds are broadly classified into different classes based on the color of their pigmentation: blue-green, green, brown, and red.

Shankar IAS Summary: Marine Organisms- 2 | Famous Books for UPSC Exam (Summary & Tests)


Functions of Seaweeds

  • Food for marine organisms.
  • Habitat for fish breeding grounds.
  • Source of sediment.

Uses of Seaweeds

  • Important as food for humans, feed for animals, and fertilizer for plants.
  • Used as a drug for goiter treatment, intestinal and stomach disorders.
  • Commercially valuable products like agar-agar, alginates, and iodine are extracted from seaweeds.
  • Biodegradation of seaweeds can produce economically important gases like methane.
  • Some seaweed extracts exhibit antibacterial activity.
  • Used as potential indicators of pollution in coastal ecosystems, particularly heavy metal pollution, due to their ability to bind and accumulate metals strongly.

Harmful Effects of Seaweeds

  • Rotting seaweed is a potent source of hydrogen sulfide, a highly toxic gas, implicated in some incidents of apparent hydrogen-sulfide poisoning, causing vomiting and diarrhea.

Question for Shankar IAS Summary: Marine Organisms- 2
Try yourself:
What are the major threats to sea grass beds?
View Solution

 Threats to Seaweeds

  • Environmental Threats

     Eutrophication, siltation, and coastal engineering harm seagrass beds. Eutrophication leads to algal blooms, siltation reduces sunlight penetration, and coastal constructions disrupt natural habitats.

  • Human-Induced Pressure
    Trawling and overexploitation for commerce directly threaten seaweeds . Trawling damages habitats, while overexploitation depletes seagrass-dependent species, jeopardizing the health and sustainability of these ecosystems.

The document Shankar IAS Summary: Marine Organisms- 2 | Famous Books for UPSC Exam (Summary & Tests) is a part of the UPSC Course Famous Books for UPSC Exam (Summary & Tests).
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FAQs on Shankar IAS Summary: Marine Organisms- 2 - Famous Books for UPSC Exam (Summary & Tests)

1. What are the functions of sea grass?
Sea grass plays a crucial role in marine ecosystems. Some of its functions include providing habitat and shelter for various marine organisms, contributing to coastal stabilization and erosion control, acting as a carbon sink by absorbing and storing carbon dioxide, and maintaining water quality by filtering pollutants.
2. How do seaweeds contribute to marine ecosystems?
Seaweeds, also known as macroalgae, have several important functions in marine ecosystems. They provide food and habitat for a wide range of marine organisms, including fish, invertebrates, and sea turtles. Seaweeds also play a role in nutrient cycling and help to maintain water quality by absorbing excess nutrients. Additionally, they contribute to coastal protection by reducing wave energy and preventing shoreline erosion.
3. What are some examples of marine organisms that rely on sea grass and seaweeds?
Many marine organisms depend on sea grass and seaweeds for their survival. Examples include manatees and dugongs, which feed on sea grass, and sea urchins and snails, which graze on seaweeds. Additionally, numerous species of fish, such as seahorses and pipefish, use sea grass beds and seaweed forests as nurseries and hiding places.
4. How do sea grass and seaweeds help combat climate change?
Sea grass and seaweeds contribute to climate change mitigation in several ways. They act as carbon sinks, absorbing and storing carbon dioxide from the atmosphere. Additionally, they release oxygen through photosynthesis, helping to counteract the effects of greenhouse gas emissions. By protecting and restoring sea grass beds and seaweed forests, we can enhance their carbon sequestration potential and mitigate climate change.
5. Are sea grass and seaweeds at risk of decline or extinction?
Yes, sea grass and seaweeds are facing various threats that can lead to their decline or even extinction. Factors such as coastal development, pollution, climate change, and destructive fishing practices can negatively impact their populations. It is crucial to implement conservation measures, promote sustainable practices, and raise awareness about the importance of preserving these valuable marine resources.
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