The Biosphere Chapter 58 1
Effects of Sun, Wind, Water Biosphere: includes all living communities on Earth Global patterns of life on Earth are influenced by 1. The amount of solar radiation that reaches different areas 2. Patterns of global atmospheric circulation which influence oceanic circulation 2
Biomes Biomes: a major type of ecosystem on land Each biome has a characteristic appearance Defined largely by sets of regional climatic conditions Biomes are named according to their vegetational structures 8 principle biomes with 6 others 3
Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. polar ice mountain zone warm, moist evergreen forest chaparral semidesert tundra temperate deciduous forest tropical monsoon forest temperate grassland desert taiga temperate evergreen forest tropical rain forest savanna Distributions of biomes 4
Mean Annual Temperature ( C) Semidesert Biomes Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 30 25 20 15 10 5 Hot desert Savanna Temperate grassland Temperate deciduous forest Tropical rainforest Temperate evergreen forest 0 Taiga 5 10 Tundra 15 50 100 150 200 250 300 350 400 450 Mean Annual Precipitation (cm) Predictors of biome distribution Temperature and precipitation 5
Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a. b. Productivity (g/m 2 /year) Productivity (g/m 2 /year) 2500 2000 1500 1000 500 2500 2000 1500 1000 500 0 0 50 100 200 300 400 Precipitation (cm/year) 10 5 0 5 10 15 20 25 30 Temperature ( C) The correlations of primary productivity with precipitation and temperature 6
Biomes Tropical rain forests 140 450 cm rain/yr Richest ecosystems on land High temperature and high rainfall Very high diversity: 1,200 species of butterflies in a single square mile 7
Savanna Biomes 50 125 cm rainfall/yr Tropical or subtropical grasslands Occur as a transition ecosystem between tropical rainforests and deserts Serengeti of East Africa 8
Deserts Biomes 25 40 cm rainfall/yr; unpredictable Plants and animals cannot depend on any rainfall 30 N and S latitudes due to global air circulation patterns Due to rain shadows Vegetation sparse, animals adapted to little water availability 9
Temperate grasslands or prairies Rich soils Biomes Grasses with roots that penetrate deep into the soil In North America converted to agricultural use Adapted to periodic fire 10
Biomes Temperate deciduous forests Mild but seasonal climates (warm summers and cold winters), plus plentiful rains Temperate evergreen forests Occur along coastlines with temperate climates Taiga and tundra Both stretch in unbroken circles around the entire globe 11
Freshwater Habitats Fresh water covers only 2% of Earth s surface Life depends on oxygen availability Oxygen per liter is only 5% of that in the atmosphere Oxygen added by photosynthesis and aeration from the atmosphere Oxygen is removed by animal and detritivore respiration, and through decaying organic matter Warm water holds less O 2 than cooler water 12
Freshwater Habitats Lake and pond habitats change with water depth Intensity of light decreases with water depth Photic zone: area where light penetrates and photosynthesis is possible Littoral zone: shallows at edge of lake Aphotic (benthic) zone: below light penetration level 13
Freshwater Habitats Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Lake Zones and Productivity Littoral zone Photic zone Productivity Aphotic zone 14
Marine Habitats 71% of the Earth s surface is covered by ocean Continental shelves: near coastlines, water is not especially deep ~ 80 km wide and 1 m to 130 m deep Average depth of the open ocean is 4,000 5,000 m deep Trenches: 11,000 m deep Principle primary producers are phytoplankton (single cell or colonial) 15
Marine Habitats Banks and coral reefs Banks are local shallow areas on the shelves Fishing grounds Coral reefs occur in subtropical and tropical latitudes Defining feature is stony corals Algal symbioses: cnidarians and dinoflagellates 16
Marine Habitats El Niño Southern Oscillation (ENSO) 2 7 years on an irregular and unpredictable basis Coastline waters become profoundly warm Primary productivity unusually low Weakening of the east-to-west Trade Winds Upwelling continues, but only recirculates the thick, warm surface layer 17
Marine Habitats El Niño can wreak havoc on ecosystems Plankton abundance can drop to 1/20th normal levels Fish stocks disappear Seabirds and sea lion populations crash On land Heavy rains produce abundant seeds and land birds flourish Increase rodent population Increase predator population 18
El Niño winter Marine Habitats Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Warmer Drier Warmer Wetter and warmer Warmer Wetter and cooler Drier Warmer Wetter and warmer EI Niño Sea temperature higher than normal Warmer Wetter 19
Marine Habitats Deep sea: cold, dark place with fascinating communities Seasonless, 2 5 C; pressure: 400 500 atm Food originates from photosynthesis in the sunlit waters 99% eaten as it drifts down through the water column Animals: small-bodied, thinly distributed 20
Marine Habitats Hydrothermal vent communities: thick with life Large-bodied animals Do not depend on the Sun s energy for primary production Depend on sulfur-oxidizing bacteria Water temperature up to 350 C Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a. b. a: Jim Church; b: Ralph White/Corbis; b(inset): NOAA Pacific Marine Environmental Laboratory s Vents Program 21
Human Impacts: Pollution Human impacts can cause adverse changes in ecosystems DDT: highly effective insecticide, sprayed in United States after WWII DDT is oil soluble and biomagnifies in the food chain Result of use Populations of ospreys, bald eagles, and brown pelicans plummeted 22
Human Impacts: Pollution Biomagnification of DDT concentrations in the food chain Predatory bird species were affected because it made their eggshells so thin that the shells broke during incubation Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. DDT Concentration 25 ppm in predatory birds 2 ppm in large fish 0.5 ppm in small fish 0.04 ppm in zooplankton 0.000003 ppm in water 23
Human Impacts: Pollution Freshwater habitats are threatened by pollution and resource use Point source pollution: comes from an identifiable location Factories Sewage-treatment plants Laws and technologies can be applied because the source is known 24
Human Impacts: Pollution Diffuse pollution: is exemplified by eutrophication caused by excessive runoff of nitrates and phosphates Dissolved oxygen declines Fish species change, carp take the place of more desirable species Can originate from thousands of lawns, farms, golf clubs, etc. Solutions depend on public education and political action 25
Human Impacts: Pollution Pollution from coal burning: acid precipitation When coal is burned, sulfur oxide is released Sulfur oxide combines with water in the atmosphere to create sulfuric acid Mercury emitted in stack smoke is a second potential problem Mercury can interfere with brain development in human fetuses and infants 26
Human Impacts: Pollution Acid precipitation and mercury pollution affect freshwater ecosystems ph levels below 5.0, many fish species and other aquatic animals die or are unable to reproduce Mercury accumulates in the tissues of food fish: dangerous to public health 27
Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Precipitation ph >5.3 <4.3 ph values of rainwater in the United States 28
Damage to trees by acid precipitation at Clingman s Dome, Tennessee. 29
Human Impacts: Pollution Terrestrial ecosystems are threatened by deforestation Single greatest problem is deforestation by cutting or burning An example is rainforest destruction Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a. b. a: Environmental Images/agefotostock; b: Frans Lanting/Corbis 30
Human Impacts: Pollution Deforestation consequences Loss of habitat Major contributing factor in increased desertification Loss of nutrients from soils Nutrient enrichment of bodies of water downstream Disruption of the water cycle Acid rain 31
Weight of Fish (thousands of metric tons) Human Impacts: Pollution Overfishing of the ocean Single greatest problem in the ocean Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. realm 100 Poaching on terrestrial animals increases when fish populations decline 80 60 40 20 0 1978 1985 1992 Year total biomass in the ecosystem biomass taken by fishing 1999 2006 32
Human Impacts: Pollution Pollution effects in the ocean Plastic found washed up on beaches in remote areas Waters are laced with toxic chemicals Biopsy of tissue from Arctic killer whales reveal high levels of pesticides and flame-retardant chemicals 33
Southern Hemisphere Ozone Hole Area (millions of square kilometers) Human Impacts: Pollution Stratospheric ozone depletion Ozone hole: over Antarctica between 1/2 to 1/3 of original ozone concentrations are present Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 27 24 21 18 15 12 2011 2010 2009 2008 2001 2010 average South Pole 9 6 3 0 August September October November December a. b. a: NASA/Goddard Space Flight Center Scientific Visualization Studio 34
Human Impacts: Pollution Over United States Ozone concentration has been reduced by about 4% Stratospheric ozone is important because it absorbs UV radiation (UV-B) UV-B damages tissue, increases risks for Skin cancer: 1% drop in ozone leads to a 6% increase in skin cancer Detrimental to amphibians 35
Human Impacts: Pollution Ozone depletion and CFCs: Major cause of ozone depletion are chlorineand bromine-containing compounds in the atmosphere Use of CFCs are being phased out in many countries CFCs are chemically stable in the atmosphere for many years Ozone depletion will continue to occur until all of the CFCs are broken down 36
Climate Change CO 2 and other gases in the atmosphere maintain the Earth s average temperature at 25 C higher than it would be without these gases Human activities are now changing the composition of the atmosphere; increasing the CO 2 and other gas levels Because of the increase, global temperatures are increasing, causing global warming 37
Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 2011 Surface Temperature Anomalies ( C) 4.1 4 2 1 0.5 0.2 0.2 0.5 1 2 4 4.4 NASA Goddard Institute for Space Studies 38
Climate Change Based on a variety of different scenarios, computer models predicted that global temperatures would increase 1.1 C to 6.4 C (2.0 11.5 F) by the end of this century Some countries will come out ahead, others will come out behind 39
Climate Change Carbon dioxide is the major greenhouse gas Other atmospheric gases also involved All authorities agree that the cause of this steady rise in atmospheric CO 2 is the burning of coal and petroleum products by the increasing (and increasingly energy-demanding) human population 40
Carbon Dioxide Concentration (ppmv) Annual Global Temperature Anomalies ( C) Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 390 0.7 380 370 360 350 340 330 320 310 1960 1970 1980 1990 2000 2010 Year 0.6 0.5 0.4 0.3 0.2 0.1 0 0.1 0.2 The greenhouse effect 41
Climate Change How CO 2 affects temperature CO 2 absorbs electromagnetic radiant energy Earth receives radiant energy from the Sun Earth also emits radiant energy The Earth s temperature will be constant only if the rates of these two processes are equal 42
Climate Change The atmosphere allows in short wave radiant energy from the Sun, but does not allow the long wave radiant energy from the Earth to escape This is the same principle as a Greenhouse Short wave in, long wave cannot get out, increase in temperature in the greenhouse 43
Climate Change Other greenhouse gases Methane: 20 times the heat trapping properties of CO 2, less concentration in the atmosphere, less long-lived Methane is produced globally in anaerobic soils and fermentation reactions of ruminant mammals Methane is locked up in permafrost Sudden release will cause large perturbation in global temperature 44
Climate Change Other greenhouse gases Nitrous oxide: agricultural use of fertilizers is the largest source Energy consumption Industrial use Evidence confirms global warming Ice free seasons 2.5 weeks longer Ice at the North Pole decreased Glaciers decreasing in size 45
Climate Change Disappearing glaciers 46
Climate Change Global temperature change has affected ecosystems in the past and is doing so now Shift in species geographic ranges Migratory birds arrive earlier at their summer breeding grounds Insects and amphibians breed earlier Wild fruit fly populations changes in gene frequency Bleaching of reef-building corals 47
Problems Climate Change Rate of warming today is rapid Evolutionary adaptations for species survival may not have time to occur Natural areas no longer cover the whole landscape Species that shift to higher altitudes may have reached the peak of the mountain Species habitat disappears entirely 48
Climate Change Effects on agriculture Positive: more CO 2 tends to increase growth of some crops Increase pollen production causing more severe allergies More droughts in some regions Decrease in crop production in tropical areas 49
Climate Change Human health Frequent flooding = loss of safe drinking water Cholera and other epidemics may occur more often Tropical diseases may invade nontropical countries Malaria Dengue fever 50