Threats to marine biodiversity
- 1. THREATS TO MARINE SK.UMME SA MFK 1710, AEM.
- 2. • The ocean was viewed as a boundless reservoir of productivity with unlimited capacity to assimilate wastes. • A Productive ecosystem is characterized by High degree of biological diversity . • Species has a well defined role to play. • Provide numerous pathways for energy of a system to flow. • The resources of the sea have been over harvested by human thereby threatening marine biodiversity.
- 3. • Threats to marine biodiversity have widespread social, economic, and biological consequences, the combination of which could threatend our own existence, including: • Economic losses through unemployment and reduced productivity • Dramatic reductions in the numbers of many popular edible fish and shellfish • Threatned species that might be useful in developing new medicines • Reduced ability of ecosystems to respond to disaster, both natural (floods) and man-made (pollution) • Accelerated global climate change • Social and political instability
- 4. MAJOR THREATS • Over exploitation - recreational and commercial • Pollution • Habitat destruction and fragmentation • Non-native species invasions • Global climate change
- 5. INTRODUCTION OF ALIEN SPECIES • Invasive species can dramatically change the structure and function of marine ecosystems by changing biodiversity and eliminating vital components of the food chain. • These species are harmful to native biodiversity in a number of ways. • For example, as competitors, predators, parasites, or by spreading disease. • Ships use water as ballast to adjust their position in the water to improve their maneuverability and stability. • Mariners typically pump water into ballast tanks at one port and discharge it when taking on cargo at another port
- 6. • Mariners have unintentionally transplanted locally native marine species to new areas with the ballast water. • The arrival of an invasive jellyfishlike organism, Mnemiopsis leidyi, led to a major ecological “regime change” in the Black Sea, Many other species have been introduced as planktonic larvae in ballast water. • There are many alien species: Many seaweeds like red algae (Kappaphycus striatum), zebra mussel (Dreisssena polymorpha), lion fish (Aquarium fish)
- 7. CLIMATE CHANGE • Global warming will cause sea level rise. • As a result higher temperature decreases the ability of water to dissolve oxygen. • Humans, however, have been increasing the amount of CO 2 in the atmosphere by burning enormous amount of fossil fuels. • Loggerhead Turtle nests in Florida have already producing 90% females owing to high temperatures, and if warming raises temperatures by an additional 1º C or more, no males will be produced there. • Coral reefs require particular environmental conditions for growth and water temperatures from 23–29 °C are optimal for growth.
- 8. • Increasing temperature too much can cause the coral polyps to expel the zooxanthellae and lead to coral bleaching where the zooxanthellae are expelled from the coral by the polyps. • Coastal power plants use seawater for cooling and discharge the warmed water at the coast. • Warming is bad for polar communities, the Arctic pack ice has been getting thinner at a rate that if maintained will result in the Arctic becoming ice free in a few decades, and with its disappearance will go polar bears, walruses and many of the other Arctic species.
- 9. POLLUTION • Pollutants in the air,water,and soil can affect organisms in many ways, from altering the rate of plant growth to changing reproduction patterns,in certain extreme situations,leading to extinction. • Coral reefs can be damaged by a variety of pollutants that are produced by a variety of sources.
- 10. • Human sewage, often untreated,can add nutrients,microorganisms and other pollutants for coral reefs depletion. • Mass mortality of fish or other marine organisms has been reported from different regions caused by the release by industrial wastes. • Animals can be poisoned or suffer internal damage from ingesting oil so marine animals become sleepy and drown.
- 12. • One of the most prevalent side effects of an oil spill is hypothermia. • Once the oil drifts into the water, it creates a sticky substances called ‘mousse’. • Oil spills affect marine life like filter feeders by concentrating the flesh of the animals. • Oil spills are especially harmful if they occur during coral spawning because the oil can kill eggs and spawn.
- 13. There are three main types of inputs of pollution into the ocean • Direct discharge of waste into the oceans •Runoff into the waters due to rain •Pollutants that are released from the atmosphere Sources of oil pollution are : •Tankers. •Ballast water •Bilage washings. •Factories etc
- 17. • Marine pollution includes a range of threats including from land-based sources – Oil spills, – Untreated sewage, – Heavy siltation, – Eutrophication (nutrient enrichment), – Persistent organic pollutants (POP’s), – Heavy metals from mine tailings and other sources, – Acidification, – Radioactive substances, – Marine litter.
- 18. OIL SPILLS
- 19. UNTREATED SEWAGE
- 20. EUTROPHICATION
- 21. marine litter
- 22. ACIDIFICATIO N
- 24. OVER EXPLOITATION • Overexploitation can lead to resource depletion and put a number of threatened and endangered species at risk for extinction. • A greater variety of species at a higher trophic level is exploited in the sea than on land: humans exploit over 400 species as food resources from the marine environment. • Worldwide, fishing fleets are two to three times as large as needed to take present day catches of fish and other marine species • The use of modern techniques to facilitate harvesting, transport and storage has accelerated the over exploitation.
- 25. • Total of almost 80% of the world’s fisheries are fully to over exploited,depleted, or in a state of collapse. • Recently, a study showed that 29% of fish and seafood species have collapsed (i.e. their catch has declined by 90%) and are projected to collapse within by 2048, unless immediate action is taken. • Worldwide about 90% of the stocks of large predatory fish stocks are already collapsed. Target species are generally the most impacted by over exploitation. • Threatening many other species, particularly large sized fishes such as tunas,sword fish, and sharks.
- 26. • Direct and Indirect effects of overfishing • Growth and recruitment overfishing • Habitat loss – benthic trawling • Ghost fishing • Trophic cascading effects
- 29. HABITAT DESTRUCTION • Loss of habitat is the major reason why aquatic biodiversity is declining. • Describes the emergences of discontinuities (fragmentation) or the loss (destruction) of the environment inhabited by an organism. • Approximately 20% of the world’s coral reefs were lost • 20% degraded in the last several decades of the twentieth century • 35% of mangrove area was lost during this time. • Extinction is a terrible waste of life and a loss of potential solutions to future problems such as possible cures to disease and solutions for survival in a changing world.
- 30. • For ex: Rising temperatures, rising sea levels, and other trends will have an effect on the world’s 6 species of sea turtles. • coral reef fish is with cyanide a poison. • Mangrove forests are routinely being cleared, with huge impacts on biodiversity. • Healthy mangrove forests provide a critical habitat for many species in intertidal and estuarine areas and are key to a healthy marine environment.
- 31. Threats to Mangroves • Tree felling for fuel wood and wood products Grazing by cattle Reclamation for agriculture and aquaculture Urban development and human settlements Industrialization, Port and Harbour development Mining Siltation and Sedimentation
- 32. CONCLUSION • Human attention rightly focuses on the decline of biodiversity on land, but this should not happen at the expense of the oceans attention to marine biodiversity • Preserving marine biodiversity for the sake of knowledge itself is important. • Biodiversity is declining very rapidly and efforts to stop the declined must be intensified . • There needs to be more public support in order to conserve.
- 33. THANK YOU