Ecosystems Chapter 48

1. EcosystemsChapter 48 All most all regions on the earth function as systems running on energy from the sun processed through photosynthesizers.

2. The Nature of Ecosystems • An ecosystem is an array of organisms interacting with one another and with the physical environment, connect by a one-way flow of energy and a cycling of materials. • Ecosystems are open systems through which energy flows and material are cycled. • Ecosystems require energy and nutrient input and generate energy (usually as heat) and nutrient output. Energy cannot be recycled.

3. Availability of nutrients as well as ENERGY profoundly influences the structure of the ecosystem

4. The Nature of Ecosystems • Primary producers are autotrophs (self-feeders) that can capture sunlight energy and incorporate it into organic compounds • Consumers are heterotrophs (not self-feeders) that feed on tissues of other organisms • Herbivores eat plants • Carnivores eat animals • Omnivores eat a variety of organisms • Parasites reside in or on living host & extract energy from them

5. The Nature of Ecosystems • Primary producers are autotrophs (self-feeders) that can capture sunlight energy and incorporate it into organic compounds • Consumers are heterotrophs (not self-feeders) that feed on tissues of other organisms • Decomposers are also heterotrophs and include fungi and bacteria that extract energy from the remains or waste products of organisms; these organisms engage in extracellular digestion • Detritivores - include small invertebrates that ingest decomposing particles of organic matter (detritus)

6. Structure of Ecosystems Trophic(“feeding”)Levels are a hierarchy of energy transfers (Who Eats Whom?) 1st level(closest to the energy source) - Primary producers (Autotrophs) 2nd level - Primary consumers (Herbivores) 3rd level - Secondary consumers (primary carnivores) 4th level - Tertiary consumers (secondary carnivores & parasites) - decomposers feed on organisms from all levels

7. 21 decomposers/detritivores top carnivores carnivores 5,060 383 herbivores 3,368 producers 20,810 Energy Flow through the Ecosystem Kcal/ sq. m / yr • Ecological Pyramids (two types) - • (1) Biomass pyramid - makes provision for differences in size of organisms by using the weight of the members in each trophic level • (2) Energy pyramid - reflects trophic structure most accurately b/c it is based on energy losses at each level

8. Food Chain A simple sequence of who eats whom is called a food chain. Interconnected food chains comprise food webs in which the same food resource is often part of more than one food chain…. Plants

9. MARSH HAWK CROW HIGHER TROPHIC LEVELS Complex array of carnivores, omnivores and other consumers. Many feed at more than one trophic level continually, seasonally, or when an opportunity presents itself UPLAND SANDPIPER GARTER SNAKE FROG WEASEL BADGER COYOTE SPIDER SECOND TROPHIC LEVEL Primary consumers (e.g., herbivores) CLAY-COLORED SPARROW EARTHWORMS, INSECTS (E.G., GRASSHOPPPERS) PRAIRIE VOLE POCKET GOPHER GROUND SQUIRREL FIRST TROPHIC LEVEL Primary producers Energy flows into ecosystems from the sun and due to heat losses at each energy transfer step, you see a one-way flow of energy. The loss of energy at each transfer in a food chain limits the number of trophic levels in each ecosystem to 4 or 5.

10. DDT Residues Ring-billed gull fledgling Herring gull Osprey Green heron Summer flounder Sheepshead minnow Hard clam Flying insects Mud snail Shrimps Green alga Plankton Water 75.5 18.5 13.8 3.57 1.28 0.94 0.42 0.30 0.26 0.160.083 0.040 0.00005 Biological Magnification in Food Webs DDT is a synthetic organic pesticide. DDT is water insoluble but winds can carry DDT in vapor form. DDT is fat soluble, so it can accumulate in the tissues of organisms. DDT can show biological magnification - it becomes more and more concentrated in tissues of organisms at higher trophic levels of a food web DDT and modified forms, disrupt metabolic activities and are often toxic to many aquatic and terrestrial animals.

11. Biogeochemical Cycle Overall movement of nutrients(ions & molecules) from the physical environment, through organisms, & then back to the environmental reservoir constitutes a biogeochemicalcycle. geochemical cycle Main nutrient reservoirs in the environment fraction of nutrient available to ecosystem herbivores, carnivores, parasites primary producers detritivores, decomposers Environment serves as a reservoir for the nutrients

12. 3 Categories of Biogeochemical Cycles 1. In the hydrologic cycle, oxygen and hydrogen move as water molecules. 2. In the atmospheric cycles, elements can move in the gaseous phase; examples include carbon (mainly CO2) and nitrogen. 3. In sedimentary cycles, the element does not have a gaseous phase; an example is phosphorus.

13. ATMOSPERE precipitation onto land 111,000 wind driven water vapor 40,000 evaporation from ocean 425,000 precipitation into ocean 385,000 evaporation from land plants 71,000 surface and groundwater flow 40,000 OCEAN LAND Hydrologic Cycle water slowly moves on a global scale from the oceans, through the atmosphere, onto land, then back to the ocean

14. Carbon Cycle diffusion between atmosphere and ocean ATMOSPHERE (mainly carbon dioxide) volcanic action combustion of fossil fuels BICARBONATE & CABONATE DISSOLVED IN OCEAN WATER combustion of wood aerobic respiration TERRESTRIAL ROCKS photosynthesis aerobic respiration photosynthesis deforestation LAND FOOD WEBS MARINE FOOD WEBS SOIL WATER PEAT, FOSSIL FUELS uplifting over geologic time incorporation into sediments death, sedimentation death, burial, compaction over geologic time sedimentation leaching runoff MARINE SEDIMENTS, INCLUDING FORMATIONS WITH FOSSIL FUELS Carbon Cycle is the global movement of carbon through ecosystems. Carbon in the atmosphere is in the form of carbon dioxide and carbon in water is in the form of bicarbonate and carbonate.

15. Greenhouse Gases and a Warmer Planet (pg 888-889)-READ! • Greenhouse effect • CO2, Ozone, Methane, Nitrous oxide, CFC’s Rays of sunlight penetrate the lower atm & warm the Earth’s surface The surface radiates heat to the lower atm. Some heat escapes into space. But greenhouse gases & water vapor absorb some infrared energy and radiate a portion of it back towards Earth. Increased concentrations of greenhouse gases trap more heat near Earth’s surface resulting in the Earth’s surface temp. to rise.

16. Greenhouse Gases and a Warmer Planet (pg 888-889)-READ! • Global warming - long-term higher temperatures at the Earth's surface • If the temperature of the lower atmosphere were to rise by 4˚C (7˚F) then the sea levels may rise by as much as 2 feet.

17. Greenhouse Gases CO2 Fossil Fuel burning Deforestation

18. GASEOUS NITROGEN (N2) IN ATMOSPHERE NITROGEN FIXATION by industry for agriculture FOOD WEBS ON LAND uptake by autotrophs excretion, death, decomposition uptake by autotrophs FERTILIZERS NO3- IN SOIL NITROGEN FIXATION bacteria convert to ammonia (NH3+) ; this dissolves to form ammonium (NH4+) NITROGENOUS WASTES, REMAINS IN SOIL DENTRIFICATION by bacteria NITRIFICATION bacteria convert NO2-tonitrate (NO3-) AMMONIFICATION bacteria, fungi convert the residues to NH3; this dissolves to form NH4+ NH3-,NH4+ IN SOIL NITRIFICATION bacteria convert NH4+ tonitrate (NO2-) NO2- IN SOIL loss by leaching loss by leaching

19. mining FERTILIZER excretion GUANO agriculture weathering uptake by autotrophs uptake by autotrophs weathering MARINE FOOD WEBS DISSOLVED IN OCEAN WATER DISSOLVED IN SOILWATER, LAKES, RIVERS LAND FOOD WEBS death, decomposition death, decomposition leaching, runoff sedimentation setting out uplifting over geolgic time ROCKS MARINE SEDIMENTS Sedimentary Cycle Most phosphate moves in the form of (PO4-3) phosphate ion

20. Eutrophication - any activity that adds dissolved nutrients to an ecosystem Runoff from agricultural applications of fertilizers adds large amounts of phosphorous to aquatic ecosystems. Human activities are accelerating the process of eutrophication. We are adding nutrients to aquatic ecosystems that are naturally low in those nutrients & so promote destructive algal blooms.