Ecosysteman ecological community plus the abiotic environment with which it exchanges energy and materials NPP varies among ecosystem types due to variation in climate and nutrient availability NPP increases with temperature and moisturewhy? Activity of photosynthetic enzymes increases Greater water and nutrient uptake through roots Why do we see decreased NPP in EXTREMELY moist environments? Tropical forests, swamps, and marshlands are the most productive NPP varies with latitude (the tropics are most productive) Aquatic NPP is strongly affected by nutrient availability and light penetration Nutrients are most abundant in near-shore areas and upwellings Hydrothermal vents are productive areas in the deep oceans, where chemolithotrophs use chemical energy rather than sunlight Aquatic NPP is highest in near-shore coral reefs and zones of upwelling because nutrients are available in the photic zone Earth is an open system with respect to energy (the sun provides energy from outside the atmosphere), but a closed system with respect to matter Energy flows in one direction through the biosphere, but matter gets recycled All the materials in the bodies of living organisms are ultimately derived from abiotic sources Biogeochemical cycles transform matter and move it around the planet Different forms and locations can be represented as compartments Create 2 rectangles on your bellringer, and label one Clear and the other Unclear. In the Clear box, write down the information from CH 45 that you feel you understand. In the Unclear box, write down any information or concepts about which you feel confused. 1. In what ways do humans impact the water cycle? 2. In what ways do humans impact the carbon cycle? 3. In what ways do humans impact the nitrogen cycle? GPP represents ALL of the solar energy absorbed by producers and converted into sugars through photosynthesis. NPP represents the stored energy (BIOMASS) that remains after plants use some of the sugars for energy (through cellular respiration) to fuel their life processes (growth, development, repair, maintenance, reproduction, etc.) The water cycle Water makes up 70% of biomass Transports materials as erosion agent Has high heat capacity redistributes heat in biosphere Human impact: Reduced vegetation increases runoff & soil erosion Groundwater pumping depletes aquifers underground Climate warming is melting ice caps and glaciers and causing sea level rise and increased evaporation. The nitrogen cycle N 2 gas is 78% of the atmosphere, but plants cannot access it Nitrogen fixation: some microbes can reduce N 2 to ammonium (NH 4 + ) Other microbial species convert ammonium into nitrate (NO 3 ) and other oxides of nitrogen (nitrification) Denitrification returns N 2 gas to the atmosphere Human impact: Burning fossil fuels, rice cultivation, and raising livestock release nitrogen compounds into the atmosphere smog, acid rain, greenhouse gas Humans fix nitrogen by an industrial process to manufacture fertilizer and explosives 4. What is eutrophication? How does it lead to algal blooms? Driven by Climate Change, Algal Blooms Behind Ohio Water Scare Are New Normal National Geographic Topsoil and fertilizer runoff from farms and deforested areas, waste water, and sewage containing nitrates are deposited in aquatic ecosystems Increased access to limiting nutrient results in eutrophication increased primary productivity and rapid phytoplankton growth (algal bloom) Decomposition of the phytoplankton can deplete oxygen; dead zones form Eutrophication causes anoxia (dead zones) because the decomposition of algae depletes oxygen in the water 1. Draw a loop that depicts the cycling of nitrogen through the processes of nitrification, denitrification, and nitrogen fixation. Include the nitrogen molecules & compounds that are involved. A. Nitrogen Fixation B. Decomposition (ammonification) C. Nitrification D. Nutrient uptake by producers E. Denitrification 1. Identify the processes represented by arrows A-E in the diagram. The carbon cycle linked to energy flow in biomass Largest compartments are fossil fuels and carbonate rock Photosynthesis moves inorganic CO2 from atmosphere into organic compartment; respiration does reverse Some dissolved CO 2 in oceans is assimilated by producers as biomass Some detritus in ocean sediments is converted to fossil fuels; carbonates can be transformed into limestone (carbon sinks) Human impact: Runoff brings carbon to aquatic ecosystems Deforestation and fossil fuel burning increase atmospheric CO 2 Atmospheric methane (CH 4 ) is increased through livestock, rice cultivation, landfills, & water storage in reservoirs Biogeochemical cycles are interconnected Carbon uptake by producers increases uptake of P, N, and other elements Limiting nutrients (the one that is in lowest supply relative to demand) can limit biological functions Increased atmospheric CO 2 can increase water-use efficiency by plants In a high CO 2 environment, plants have stomata open less reduces loss of water vapor Greenhouse effect Some reflected solar radiation is absorbed by greenhouse gases that trap heat Greenhouse gases include H 2 O, CO 2, CH 4, & N 2 O Greenhouse gases absorb much of the surface re- radiation and radiate it back to the surface 1. What are the causes of global warming? 2. What are the consequences ? Measurements from Mauna Loa in Hawaii show a steady increase in CO 2 since 1960 Air trapped in glacial ice demonstrate CO 2 and other greenhouse gases began increasing after about 1880 Average annual global temperature has also increased Higher global temperatures are affecting climate Greater overall evaporation and precipitation Wet regions will get wetter and dry regions drier Stronger storms Warming is expected to causes Hadley cells to expand poleward; warmer air will rise higher and expand farther before sinking causing precipitation to increase near the equator and at high latitudes and decrease at mid-latitudes Precipitation trends in the twentieth century support these expectations Human impact Adding greenhouse gases Deposition of dust and dark-colored soot particles (black carbon) from fossil fuel burning increases amount of solar energy absorbed by snow and ice increases melting Adding aerosols to the atmosphere increases reflectance of solar energy Recent warming and other climate changes are far more rapid than anything organisms have experienced in their evolutionary histories Climate change is altering the timing of environmental cues Rates of evolution may be too slow to keep up Many species seem to be adapting Ex: trees leafing out earlier in spring Temporal relationships among cues are shifting timing mismatches among species may emerge, which will disrupt interactions Ex: oaks, moths, and insect- eating birds If populations cannot respond to changing environments, they may go extinct Shifts in the geographic distributions can lead to assembly of novel communities Species have moved up mountains and towards higher latitudes Species shift at different rates or not at all, resulting in different species combinations Increased frequency of extreme climate events will also alter species distributions Present climate change is due to activities of a single species: Homo sapiens. But, science equips us to understand the natural world and devise solutions to problems A major challenge is that economic policies of every nation aim for continual economic growthever-increasing production and consumption of goods and services despite the fact that Earth has finite resources. A related challenge is the continued exponential growth of the human population. On a crowded planet, cooperation becomes more difficult How does deforestation contribute to global warming?