Chapter 4. Environments and Life

Transcription

1 Fig , p. 289

2 Chapter 4 Environments and Life 2

3 Guiding Questions What factors determine the ecological niches of species, and by what means do species obtain nutrition? What factors govern the geographic distribution of species? What factors govern the distribution of aquatic life? 3

4 On land growth of plants is largely limited by water. In the ocean growth of plants is limited by nutrients and/or light.

5 Fig. 13-8, p. 306

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7 What is productivity? It is photosynthesis. Sometimes referred to as primary productivity. In its simplest form, focusing on the carbon: CO 2 + H 2 O CH 2 O + O 2 Carbon dioxide Water Carbohydrate Oxygen

8 And it s really part of a larger carbon cycle. Photosynthesis (light) CO 2 + H 2 O CH 2 O + O 2 Chemical (oxidative) energy Respiration

9 Fig. 13-5a, p. 303

10 Fig. 13-5c, p. 303

11 Fig. 13-6a, p. 304

12 Fig. 13-7c, p. 305

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14 Surface Water Temperature (SST)

15 Surface Water Phosphate Concentrations NOAA-NESDIS-National Oceanographic Data Center- Climatology

16 Fig. 12-6a, p. 276

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19 Examples of where there are high rates of photosynthesis in surface ocean water: Nearly all continental margins Near River Mouths: Congo, Amazon, Mississippi Coastal Upwelling: Peru, Namibia & NW Africa Open ocean; low latitudes: Equatorial Pacific, Indian Ocean (Arabian Sea), Open ocean; high latitudes: North Atlantic and Pacific, Southern Ocean (polar fronts, convergent and divergent zones)

20 Net Production and Precipitation Net production increases rapidly with increasing precipitation, but levels off at higher values Figure 8.8, p.287

21 Ocean Surface Currents Midlatitude gyres contribute to zonal asymmetry in subtropics: cold on west coasts, warm on east coasts

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23 Ecology Ecology Study of the factors that govern the distribution and abundance of organisms in natural environments Habitats Environments on or close to Earth s surface inhabited by life Terrestrial Aquatic Marine Freshwater 23

24 Ecology Ecologic niche The way a species relates to its environment, including food, nutrients, physical and chemical conditions Life habit The way a species lives within its niche Limiting factors Naturally occurring, restricting condition (physical and chemical) Competition Shared drive for limited resources Predation 24

25 Ecosystem Ecosystem Organisms of a community and the physical environment they occupy Population Group of individuals that belong to a single species and live together in a particular area 25

26 Ecologic community Ecosystem Populations of several species living in a habitat Producers Photosynthesizing organisms; foundation of community Consumers Herbivores: feed on producers Carnivores: feed on other consumers 26

27 Biota Ecosystem Fauna: animals and protozoans of an ecosystem Flora: plants and plantlike protists Food chain Sequence of consumption for producers to consumers 27

28 Fig. 12-8, p. 277

29 Ecosystem Food web More complex than simple food chain More common Several species occupy each level Parasites Feed on living organisms Scavengers Feed on organisms that are already dead 29

30 Ecosystem Diversity The variety of species that live together within a community Lower in more difficult habitats Predation influences diversity Heavy can reduce diversity Moderate can increase diversity by reducing competition Opportunistic species Species that specialize in invading newly vacated habitats 30

31 Biogeography Distribution and abundance of organisms on a broad geographic scale Limiting factors Diversity increases toward equator Barriers can affect dispersal 31

32 Climate Classification (Köppen)

33 Atmospheric Circulation Net transport Air sinks at the poles, rises at the equator Simplified model No tilt No Coriolis effect 33

34 Atmospheric Circulation Actual pattern is more complex Three circulation cells Trade winds, westerlies, easterlies Intertropical convergence zone Northern, southern trade winds converge near equator Changes seasonally 34

35 Temperature Variations Atmosphere retains heat Solar radiation Absorbed and turned into heat energy Reflected 6-10% ocean 5-30% forest 45-95% ice and snow 35

36 Terrestrial Realm Vegetation follows climatic zone Tropical rain forest Desert savannahs Temperate forests Polar tundra 36

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38 Climate Zones Circulation features are tied to regional climate Rising air associated with lots of precipitation

39 Temperature Patterns Stronger seasonal heating and cooling on land produces asymmetry Poleward distortion of isotherms over northern high latitude oceans Equatorward distortion over subtropics

40 January July Precipitation (mm/month) Very wet over tropics Seasonal shift (N/S) Monsoon regions Extremely dry subtropical highs Midlatitudes get more summer rain July rainfall looks like a map of forest cover

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42 Terrestrial Realm Tropical Climates C (64 68 F) 0 30 latitude Tropical Rain Forest Dense vegetation 42

43 Terrestrial Realm Deserts Dry trade winds remove moisture north and south of the equator < 25 cm rain/year Little vegetation Savannah, grasslands Too dry to support forests 43

44 Poles Defined by ice sheets and glaciers today Absent or reduced at times in the past Terrestrial Realm 44

45 Terrestrial Realm Glaciers Ice in motion Glide and spread Present at high latitudes and high elevations near equator 45

46 Tundra Limited water Grasses, sedges, lichens, shrubs dominate Cannot support tall trees Evergreen coniferous forests South of tundra Spruce, pine, fir Terrestrial Realm 46

47 Terrestrial Realm Temperate forests Longer summers, slightly warmer Deciduous trees Maples, oaks, beeches Mediterranean climate Dry summers, wet winters Common 40 N and S of equator Californian, Mediterranean region 47

48 Climate Climate Controls distribution of species globally Has changed through time Plate tectonics and other changes affect climate 48

49 Climate Altitude Similar to latitudinal gradient At base Deciduous forest On slopes Evergreen forest Tundra above treeline At top Glaciers 49

50 Mountains Rain shadow Prevailing winds bring moisture Precipitation on windward side Aridity on leeward side Climate Rain shadows common on east side of North American mountain chains 50

51 Seasonal Change High heat capacity of water Less change in ocean temperatures than on land Monsoon Circulation Summer winds flow onshore; bring rain Winter winds offshore Climate 51

52 Plants as Climate Indicators Sensitive indicators of change Cycads Tropics and subtropics today Fossil distribution allows reconstruction of climate patterns 52

53 Plants as Climate Indicators Leaf Margins Tropics Smooth, waxy margins Temperate climates Jagged margins 53

54 Ocean currents Wind driven Follow atmospheric patterns Trade winds Push waters west; form equatorial currents Equatorial countercurrents Return flow Gyres Clockwise in Northern Hemisphere Gulf Stream Marine Realm 54

55 Circumpolar current Circles Antarctica Very cold Marine Realm 55

56 Marine Realm Polar circulation Sea ice leads to more saline water Cold, dense waters sink Antarctic waters Flow north at depth Arctic waters Flow south at depth 56

57 Ocean circulation Waves Surface waves Tides Marine Realm Wind driven Break when seafloor interacts at shallow depths Cause major movement of water in oceans Due to rotation of solid Earth beneath bulges of water produced by gravitational attraction of the moon 57

58 Continental Shelf Submarine extension of continental landmass Shelf break Edge of shelf ~200 m w.d. Continental Slope Continental Rise Abyssal Plain Marine Realm 58

59 Marine Realm Near shore Barrier islands Marshes Epicontinental seas 59

60 Photic Zone Region of ocean where enough light penetrates to permit photosynthesis Pelagic life Plankton Phytoplankton Zooplankton Nekton Benthic life Suspension feeders Deposit feeders Marine Realm 60

61 Marine Realm Marine Biogeography Tropical Subtropical Transitional Subarctic 61

62 Marine Realm Corals Most require warm water Common in tropics Reef builders Coral polyp Builds coral cup Connected to other polyps Symbiotic relationship with algae 62

63 Marine Realm Salinity Limiting factor near shore Oceanic 35 ppt Brackish Lower than marine Bays, lagoons Hypersaline Higher than marine Hot arid climates 63

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66 GlobalProd_Seawifs.mpg NASA/Goddard Space Flight Center, The SeaWiFS Project and GeoEye, Scientific Visualization Studio SeaWiFS Ocean Biosphere: 1997 to 2006

67 seawifs-6year.mpg 67

68 SeaWiFS Biosphere OceanProd_SeaWifs.mpg NASA/Goddard Space Flight Center, The SeaWiFS Project and GeoEye, Scientific Visualization Studio

69 NAtlBloom_Seawifs.mpg NASA/Goddard Space Flight Center, The SeaWiFS Project and GeoEye, Scientific Visualization Studio SeaWiFS Biosphere: North Atlantic

70 Amazon_NAfr_Seawifs.mpg NASA/Goddard Space Flight Center, The SeaWiFS Project and GeoEye, Scientific Visualization Studio SeaWiFS Biosphere: Amazon River

71 Congo_SeaWifs.mpg NASA/Goddard Space Flight Center, The SeaWiFS Project and GeoEye, Scientific Visualization Studio SeaWiFS Biosphere: Congo River & Namibia