What Forms of Pollution are Especially Harmful in Ecosystems?

1. What Forms of Pollution are Especially Harmful in Ecosystems? • Air pollution • Particulates and Heavy Metals • Industrial sources (ex. steel plants) and car exhaust • Can be toxic, decrease immunity, and aggravate asthma • Acid rain: from nitric acid (car exhaust) and sulfuric acid (coal) • Acids increase solubility of some toxic heavy metals • Forests decline: Eastern Europe, U.S. Midwest (crosses boundaries) • Water pollution: point and non-point sources • Biomagnification: heavy metals and persistent organic pollutants (POP’s) are difficult to metabolize and/or detoxify  concentrate in livers, fats of top predators (ex. DDT with egg-thinning effects  endangered bald eagles and pelicans); others weaken immune systems or cause feminization (ex. fish in Lake Mead) • Eutrophication and Sedimentation: excess plant nutrients lead to algal blooms; when algae die, leads to excess decomposition and thus high biological oxygen demand (BOD); can lead to fish kills; excess sediment smothers corals and mucous-feeding invertebrates; sewage treatment reduces both problems • Garbage: dumping in ocean outlawed in United States; plastics build up in central Pacific Ocean (center of gyre) and eaten by loggerhead turtles (mistake for jelly- fish); seabirds ingest and feel full, regurgitate garbage to their offspring

2. Figure 55.19

3. Figure 55.20

4. Figure 55.18

6. Noise Pollution Affects Marine Mammals (Acoustic Umwelt)

7. Finally – Proof of Deafness!

8. Are Introduced Species a Form of Pollution? • Exotic, non-native species (vs. indigenous species) • The only pollution that creates more of itself • Can be accidental (ex. ship ballast introduces marine species via larvae) or purposeful (ex. mongoose in Hawaii; many fishes) • Can have large effects on ecosystems since native species have not co-evolved competitive or anti- predation mechanisms • Main causes of species extinctions and endangerment in Hawaii and Puerto Rico (including many endemic species) • Often controversial regarding removal or treatment: poisoning of Lake Davis (CA) to remove pike; shooting goats on Catalina Island • Other examples: Africanized (“killer”) bees; brown tree snake (Guam); zebra mussels; “Med Fly”

9. Figure 56.8

10. How do Species Become Endangered, and How are They Protected? • Common Characteristics of Endangered Species: small, localized ranges (including islands), fragmented populations (often due to human activities), low reproductive success • U.S. Endangered Species Act (ESA): 1973; enforced by U.S. Fish and Wildlife Service or National Marine Fisheries Service • Endangered status: in “imminent danger of extinction throughout all or significant part of its range” • Protects habitat; can be applied to a specific sub-population • Threatened status: in “forseeable risk” of extinction • Examples: white shark (Calif. ESA) with naturally low populations and targeted fisheries for sport/jaws; polar bear recent listing • Listings: umbrella species chosen to protect entire ecosystem (ex. spotted owl chosen to protect old-growth forests); flagship species (high profiles, ex. panda, bald eagle); sentinel (bellweather) species first to show effects of environmental stress (ex. amphibians exposed to air and water pollution); keystone species • Controversies: populations difficult to measure; some listings seem “crazy” (ex. fly in Colton); is it effective? (few de-listings); habitat protection often conflicts with private-land ownership

11. Figure 56.4

12. Figure 56.10

13. Is Aquaculture the Solution for the Over-fishing Problem? • Over-fishing: 90% of fisheries over continental shelves; led to 200-mile exclusive-use zones; international fisheries include Bering Sea, Gulf of Alaska, Grand Banks, Southern Capes (Good Hope, Horn) • Due mainly to increased technology: spotter planes, satellite data, larger nets and longer long-lines • Biggest problems: bycatch; fishing at low trophic levels; subsidization and flags of convenience (escape international treaties) • Trawling degrades habitat and has high level of bycatch • Shark fisheries: mainly for shark-fin soup  finning • Sharks do not support fisheries due to low reproductive potential • Reserves replacing quotas and size limits; easier to enforce and evidence that they work (most fishes with planktonic larvae) • Aquaculture and Mariculture (marine aquaculture) • Shrimp, salmon, lobster mainly for feeding relatively wealthy; all use fish meal and contribute to over-fishing (net loss of biomass) • Tilapia and shrimp farms often destroy coastal wetlands/mangroves • Dense populations lead to disease  antibiotics enter ecosystems • Escapes common; concern over effects on natural gene pools

14. Figure 56.9

16. Figure 54.24

17. Is the Ozone Layer Still Threatened? • Stratospheric Ozone Depletion • Ozone a component of smog in lower atmosphere; in upper atmosphere, shields Earth from UVB radiation • Chlorofluorocarbons (CFC’s) lighter than air, rise to upper atmosphere, where they stick to ice crystals; each molecule able to destroy many ozone molecules (most during summer); Antarctic ozone hole detected in 1985, Arctic ozone hole detected in early 1990’s; global ozone declining (ex. Toronto, UV increased 5.3% per year from 1989-1993) • Effects of UV: skin cancers, stress immune systems, coral bleaching, reduces productivity of phytoplankton • International Response: Montreal Protocol (1987) phased out production of CFC’s, but existing CFC’s stable (long-lived; ex. freon)

18. Figures 55.23-55.25

19. What Evidence Supports the Theory of Global Warming? • A theory, supported by multiple lines of evidence (that current observed warming trend is due largely to human-caused influences) • Greenhouse Effect: greenhouse gases trap warm air in lower atmosphere (esp. carbon dioxide, methane, and carbon monoxide) • Combustion of fossil fuels adds CO2 to atmosphere; deforestation is often via burning (combustion) and loss of trees reduces uptake of carbon dioxide; more cattle  more methane (proposal for effort to measure this effect laughed out of U.S. Congress as “cow-fart study”) • Observed: rise in atmospheric CO2; global atmospheric and oceanic warming; rising sea levels (Tuvalu, Kiribati, other Pacific islands flooding); retreat of mountain glaciers, Arctic ice thinned, Antarctic ice shelves apparently breaking up; tropical diseases and insects spreading; regional climates shifting, affecting species ranges and causing extinctions; widespread coral bleaching; lower heating costs on the “bright side”

20. Figure 55.21

21. What are the Predicted Effects of Global Warming and the International Response? • Predicted: approx. 6°C rise by 2100; warming of tundra releases more CO2,melting of polar ice reduces reflection of energy by white ice and accelerates melting (vicious cycles); melting of West Antarctic ice sheet would raise sea level by 20 feet, flooding London, New York, Florida, New Orleans (among others); cooling of Northern Europe due to likely disruption of Gulf Stream current by melting Arctic (more icebergs will also endanger ships); rise in intensity of tropical cyclones due to warmer water temperature • Debate among specialists is mainly regarding the ocean’s role in the absorption of CO2 (but note that levels steadily rising in atmosphere, corresponding to steady rise in combustion/emissions) • Public debate mainly regarding Earth’s natural cycles of warming/cooling and lack of “definite proof”; also regarding economic costs of reducing carbon emissions • International Response: Rio Earth Summit (1992) – agreed that Global Warming is serious problem and response needed by year 2000 (George Bush Sr. signed); Kyoto Accord (1998) – signed by nearly all nations; Copenhagen (Dec. 2009); Adapt (?): sea walls planned in Thailand and Bangladesh