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Chapter 11 presen part 1
Major threats to aquatic biodiversity include habitat loss, invasive species, pollution, climate change, and overexploitation, which are exacerbated by human population growth. The greatest marine biodiversity is found at coral reefs, estuaries, and on the deep ocean floor. While protections for whales have led to recovery of some populations, others are still threatened by illegal hunting. Invasive species like the Asian swamp eel and lionfish degrade ecosystems, while activities such as agriculture, development, and waste dumping pollute waterways and oceans. Climate change poses a growing threat through sea level rise, warming, and acidification. Overfishing has driven many fish species toward extinction.
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Similar to Chapter 11 presen part 1
Chapter 11 presen part 1
- 1. Sustaining Aquatic Biodiversity Part1—Major Threats Sky Harbor Interna.onal Airport Built on Hohokam Canals. Archaeology Magazine. 2014 April 1.
- 2. Fig. 11-‐1, p. 250 Cetaceans are Whales Toothed whales Sperm whale with squid Killer whale Narwhal Bottlenose dolphin 0 2 4 6 8 10 1214 16 18 20 22 24 26 28 30 Meters Baleen whales Blue whale Fin whale Bowhead whale Right whale Sei whale Humpback whale Gray whale Minke whale 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Meters
- 3. Is Protecting Whalesa Success Story? • Cetaceans are toothed whales and baleen whales • 8 of 11 major species hunted to commercial extinction by 1975 • 1946 International Whaling Commission (IWC) • Quotas based on insufficient data • Quotas often ignored • 1970 U.S. • Stopped all commercial whaling • Banned all imports of whale products • 1986 IWC moratorium on commercial whaling • Differences in kills—42,480 whales killed in 1970, 1500 killed in 2009 • Norway, Japan, and Iceland ignore moratorium
- 4. Major Threats toAquatic Biodiversity? Aquatic species are threatened by habitat loss, invasive species, pollution, climate change, and overexploitation, all made worse by the growth of the human population.
- 5. We Have Muchto Learn about Aquatic Biodiversity • Greatest marine biodiversity at • Coral reefs • Estuaries • Deep-ocean floor • Biodiversity is higher • Near the coast than in the open sea • In the bottom region of the ocean than the surface region • Vampyroteuthis infernalis Cephalopod of the Week. 2014 April 1.
- 6. Fig. 8-‐15, p. 181
- 7. Human Activities Destroyand Degrade Aquatic Habitats Fig. 11-‐2, p. 252
- 8. Invasive Species AreDegrading Aquatic Biodiversity • Invasive species • Threaten native species • Disrupt and degrade whole ecosystems • Two examples • Asian swamp eel in the waterways of south Florida • Lionfish in the Atlantic
- 9. Fig. 11-‐3, p. 254 “An almost perfectly-designed invasive species”
- 10. Loosestrife and Carp • Lake Wingra, Wisconsin invasive species • Purple loosestrife (Lythrum salicari) • Invades wetlands • Intentionally imported from Europe and Asia • Still sold in most states as ornamental • Common carp (Cyprinus carpio) • Degrade aquatic vegetation on which birds depend • Intentionally imported from Europe and Asia • Considered sport fish, eats natives
- 11. Invaders Have RavagedLake Victoria • Nile perch deliberately introduced, fine food source • Loss of biodiversity, for example cichlids • Now frequent algal blooms in positive feedback loop • Nutrient runoff • Spills of untreated sewage • Less algae-eating cichlids
- 12. Invaders Have RavagedLake Victoria • Water hyacinth freed from insect predators • Blocks sunlight and consumes oxygen • Reduces biodiversity in the lake • Scientists reduced the problem at strategic locations by removing the hyacinth and by introducing two weevils (a type of beetle) that feed on the invasive plant.
- 13. Population Growth andPollution Can Reduce Aquatic Biodiversity • More noise and crowding from humans • Nitrates and phosphates, mainly from fertilizers, enter water • Toxic pollutants from industrial and urban areas • Plastics • The "plastisphere" is a term coined by marine biologist Erik Zettler to describe the creatures who thrive on hard surfaces in water. Before human- made hard surfaces were everywhere, they would have lived on rocks or flotsam. • The problem with the plastisphere is that it's radically changing the balance of a sea ecosystem that was once mostly just open ocean creatures. •
- 14. North Pacific Gyre • Most pieces of garbage in the Pacific Gyre are "about the size of your pinkie fingernail,” according to Scripps Institution marine biologist Miriam Goldstein. • Most are microscopic. • What's alarming about them isn't their size, but the sheer amount of plastic. • Listen to Miriam—http://youtu.be/tFSv2eW7g6E
- 15. Climate Change isa Growing Threat • Sea levels rise • Aquatic biodiversity threatened • Coral reefs • Low-lying islands • Drown many highly productive coastal wetlands • New Orleans, New York City, Maldives
- 16. Overfishing and Extinction • Marine and freshwater fish are threatened with extinction by human activities more than any other group of species. • A fishprint is the area of ocean needed to sustain the fish consumption of a person, country, or the world. • Commercial extinction means a species is no longer economically feasible to harvest. • Collapse of the Atlantic cod fishery caused a domino effect • Fewer larger fish • More problems with invasive species • Increase in algae and bacteria with fewer predators to eat them
- 17. Natural Capital Degrada.on: Collapse of the Cod Fishery Off the Canadian Coast Fig. 11-‐7, p. 257
- 18. Clashing Scientific ViewsCan Lead to Cooperation and Progress • Ray Hilborn and Boris Worm disagreed about the long-term prognosis for the world’s fisheries • Then the two agreed to work together • Developed new research methods and standards • Examined maximum sustained yield • Reported findings and prognosis in 2009
- 19. From Their Paper Marineecologists and fisheries scientists often tend to favor contrasting approaches, and we observe that these schools of thought have polarized over time. We now recognize this situation as counterproductive and propose to address this controversy where possible. In the proposed Working Group we are trying to define common ground among marine ecologists and fishery scientists by (1) developing a unifying terminology and a common analytical framework for assessing marine fisheries and ecosystem change (2) applying this framework to a number of representative marine ecosystems around the globe (3) assessing management successes and failures in order to identify a set of tools that have been proven to reverse trends of degradation in marine fish stocks and ecosystems… The central question we are trying to answer is: how can we merge contrasting objectives, tools, and scientific criteria among marine ecology, fisheries science, and management into a unifying framework. We envision that this group will be acting as a catalyst for joining scientific forces in a quest to sustain and restore valuable marine resources.
- 20. Major Commercial Fishing Methods Used to Harvest Various Marine Species Fig. 11-‐8, p. 259