Threats to marine ecosystems Group two The marine

Threats to marine ecosystems Group two

The marine ecosystem; ØIs part of the general aquatic ecosystem. ØThe later being divided into two: üMarine ecosystem üFresh water ecosystem ØMarine ecosystems cover approximately 71% of the earth’s surface and contain approximately 97% 0 f the planets water. ØThey are distinguished from freshwater ecosystems by the presence of dissolved compounds, especially salts in the water. Approximately 85% of the dissolved materials being sodium and chlorine. ØThey generate 32%of the world’s net primary production.

Benefits of the marine ecosystem Ø It is impossible to ignore the many benefits that the marine ecosystem confers to human beings. Including: being a source of food, minerals and leisure activities.

Threats to marine ecosystem 1. Dumping of wastes into oceans. ØWaste from cruise ships are dumped into the ocean waters that in turn affect the water clarity of the ocean. ØSurface runoff introduces pollutants from land into the oceans. Untreated sewage, soil nutrients and fertilizers increase nutrients causing eutrophication which crowds out corals and other marine forms of life. ØUntreated sewage introduces pathogens into the coral reefs that in turn cause coral diseases, For example white pox by Serratia marcescens. ØSediments deposited onto coral reefs smothers the corals thereby affecting their development.

Threats to marine ecosystem cont. 2. Marine debris. ØIs any human made object that wanders off and enters the coastal and ocean waters. ØAbandoned fishing nets tend to trap and eventually kill fish as well as coral reef organisms. On top of that it also damages the coral reefs.

Threats to marine ecosystem cont. 3. Use of dynamite in coral mining. ØIt kills almost all organisms within a 20 m radius of each blast. ØIt destroys the coral habitat through the loss of reef substrate that in turn hinders recruitment of coral polyps. 4. Overfishing. ØIt negatively affects the balance in marine diversity. ØIt results in fishing down the food chain, which reduces the number of herbivorous species e. g. Parrotfish and surgeon fish, which leads to an overgrowth in algae in the reef as well as other habitats. ØThere will be a disappearance of numerous life forms in such habitats.

Threats to marine ecosystem cont. 5. Destructive fishing tendencies ØUse of cyanide tablets kills marine species that are sensitive to even the smallest amounts of it. ØConstant use of cyanide kills the corals leading to the destruction of the coral reef. ØBottom trawling stirs up the bottom and in turn; • Causes pollutants to mix into plankton thereby creating harmful algal blooms • Displaces and severely harms some marine species. • Creates dead zones which is very detrimental to the sessile marine organisms like sponges, coral and anemones.

Threats to marine ecosystem cont. 6. Dredging ØIt leads to the destruction of several habitats thereby exposing the animals to predation. ØEnvironmental dredging at times causes regrouping of harmful particles and contaminates large areas of water bodies. 7. Plastic pollution. ØPlastic straws choke seabirds and sea turtles after them mistaking the straws for food.

Threats to marine ecosystem cont. 8. Noise pollution. ØMostly from engine noise to cruise ship entertainment noises. ØIt hinders living of marine life as they depend on underwater sounds for Basic life functions Øthe intensity of the noise is higher than that through gases and results in death of cetaceans (whales and dolphins), an imbalance in the marine diversity following migration, an increase in the mortality rates of some fish , e. g. the herring and the cod at birth.

Threats to marine ecosystem cont. 9. Rise in the sea water level. ØSeveral marine life species will lack habitats and nesting points will be slowly submerged in water. Examples include; üSeals nest on rocky shores and islands. üTurtles nest on sandy shores. -Mangroves are affected due to an increase in salinity at the landward zones.

Threats to marine ecosystem cont. 10. Oil spills. ØExamples; Exxon Valdez's oil spill and Deepwater Horizon. ØIt cuts oxygen supply killing thousands of marine species. ØIt destroys the insulating ability of several fur-bearing marine species. ØAlso destroys the water repellency of birds’ feathers. The marine mammals and the birds in turn die from hypothermia.

Threats to marine ecosystem cont. 11. Climate change. Ø It results in an increase in ocean temperatures that causes coral bleaching. While some corals eventually survive bleaching most of them die of starvation. Ø Increased carbon (iv) oxide emissions results in ocean acidification which results in the erosion of the calcium carbonate shells of most marine species. It also leads to destruction of the coral reef ecosystem as coral skeletons are hindered from growth. 12. Killer algae. -Caulerpa taxifolia is a highly resistant algal species, (can survive nutrient deprivation and still thrives in heavily polluted waters), that contains a toxin that is lethal to fish and invertebrates. -It is also inedible to general herbivores.

Conclusion ØGlobally, there has been a surge of interest in designating areas of sea as marine reserves , to protect and conserve marine species and habitats. Crisis facing marine life are increasing and attracting more public attention. Over the years, many species have been exploited are more at risk. A significant overall reduction in fishing mortality is the immediate ecosystem-based approach to re-building and sustaining fisheries and marine ecosystems.

Illustrations

Illustrations Cont.

Illustrations Cont.

Illustrations Cont.

Group Members NAME REGISTRATION NUMBER Asoo Gilbert Charles I 23/4887/2017 Michael Machongo I 23/4890/2017 Lucky Wanjiru Chavangi I 23/4633/2013 Belinda Omino I 23/4881/2017 Yvette Jane Akinyi I 23/4892/2017 Natasha J Maina I 23/4856/2017 Bernard Odero I 23/4573/2017

References The Commonwealth. “Marine Pollution. ” https: //thecommonwealth. org/marine-pollution. Accessed 29 October 2020. National Geographic. “Marine Pollution. ” Resource Library -Encyclopedic Entry, https: //www. nationalgeographic. org/encyclopedia/marinepollution/#: ~: text=Marine%20 pollution%20 is%20 a%20 combination, and %20 to%20 economic%20 structures%20 worldwide. Accessed 29 October 2020. NOAA. “Each Year, Billions of Pounds of Trash and Other Pollutants Enter the Ocean. ” Ocean Pollution, https: //www. noaa. gov/education/resourcecollections/ocean-coasts/ocean-pollution. Accessed 29 October 2020.