Ecosystems & Restoration 135-ch55-slides PDF

Ecosystems & Restoration Ecosystems Collections of both biotic (community) and abiotic elements interacting in an area Two major components: Energy flow: transfer of energy (from entry (primary producer) to exit (loss, typically as heat)) [open system requiring...

Ecosystems & Restoration Ecosystems Collections of both biotic (community) and abiotic elements interacting in an area Two major components: Energy flow: transfer of energy (from entry (primary producer) to exit (loss, typically as heat)) [open system requiring constant input of usable energy] Chemical cycling: movement of elements through system (ex: carbon, nitrogen) involving both abiotic and biotic components [closed system; materials are endlessly recycled but do not fundamentally enter or exit] Thermodynamics reminder Laws of conservation of energy & mass Cannot create/destroy energy Can transform it BUT some usable energy will be lost (entropy increases) Cannot create/destroy matter Materials can be lost from an ecosystem, but they aren’t destroyed, just shifted Most energy & matter can be followed through trophic interactions & biogeochemical cycles But…trophic levels end at the top of the pyramid, right? Decomposers/detritovores consume detritus (nonliving organic materials), thus ALL food chains end with this group & re-enter the system Dung beetles Energy Flow & Productivity Nearly every system on earth operates using solar energy (photosynthesis) Productivity measured as: Gross primary productivity (GPP): the rate of energy accumulation/production by primary producers Net primary productivity (NPP): GPP minus metabolic energy used during production (plants use the energy they produce) NPP is a valuable measure of energy available to support other trophic levels Measured as energy/area/time or biomass added/unit/time Note: biomass added is *new* biomass, not total biomass  Why does primary productivity vary? 2003 GPP map Biomes/ecosystems are different Photoautotrophs don’t operate well with: no N competing raw materials for E Lack of water or light Limited nutrients (often N, P) > - nobuildings for plant growth. So, most highly productive areas are warm, wet, and well-lit (tropics) or highly fertile (upwelling zones) nitrogen fixing - form bacteria Too much nutrients can be a problem Eutrophication: overgrowth of producers (often due to runoff of sewage, suffocate - agricultural fertilizers) leading to living things excessive decomposition and anoxic conditions to raw materials Plants have access High NPP - · numid met , of consistent light lots  numente 1 dem dra y Chemical Cycling freezea fil Materials necessary for life must be constantly available for living organisms; decomposers and biogeochemical cycles make inorganic nutrients available Decomposer activity influenced by temperature, moisture, and nutrient availability Warm, humid, nutrient-rich systems cycle rapidly (with diverse, productive decomposer communities) and hold most nutrients in living parts of the ecosystem Cold, dry, nutrient-poor systems cycle slowly and may accumulate large portions of materials in non-living components  Biogeochemical Cycles large scale system Natural movement of elements through systems via living (bio) and non-living (geo) processes; generally much longer, larger-scale processes than decomposition Include multiple elements of an ecosystem (air, water, land) Can be viewed locally or globally Major cycles: (4) Water (major player in other cycles by transporting elements) Carbon (of particular interest due to CO2 fluctuations & climate change) Nitrogen (mostly in unusable atmospheric form) Phosphorus (largely found in rocks/soil & living things, not in atmosphere) - know generalized concept ↑ not so much on components Digging up carbon's release ofnow human impact ↓ Balances C Cycle => off.  of cliff sides o erusion are destroyed S- lost if ecosys. access to E. > mitigate pest control - · transmission - cultural heritage disease Function · environ · Quality/ecosys desthetic humans affected by - severly Why is a healthy ecosystem useful? Despite seemingly being removed from nature, modern life is strongly dependent on ecosystem functioning (ecosystem services) providing a wide range of benefits Biodiversity & ecosystem services video clean to air · raw materials · medicine derived from plants green spaces= temperature regi