species,(populaons,( communies€¦ · ourjob:(provide(comprehensive(inputabout:((•...
TRANSCRIPT
Species, Popula.ons, Communi.es
Interac.ons in Water Ecosystems
We are being hired to: • Research for writers of a science fic.on book and screenplay.
• The writers want to create a doomsday scenario in a scien.fic, research-‐based context
Our job:
Provide comprehensive input about: • Physical, chemical, and biological proper.es of water environments
• Species interac.ons • Popula.on dynamics • Human impacts
water ecosystems
• Marine (Ocean) / Reefs • Mangroves / swamps • Estuaries / Wetlands / Lagoons • River / Riparian • Lake • Ice / Glaciers
Physical, Chemical
• Geographic loca3on or loca3on type • Zones • Light • Temperatures • Presence of oxygen, nutrients, salt • Geological factors – rock, soil • Chemical factors – inorganic reac3ons
Biological
• Species and Niche • Community Proper.es • Environmental Pressures • Popula.on Dynamics
Proper.es of Water • Makes up 70% of Earth’s surface • 97% is salt, 2% is frozen, 1% is fresh • Greatest density at 4° C. • Due molecular polarity, it has high adhesion • High Specific heat -‐ can absorb energy without rapid temperature increase
• Ice (solid) is less dense than liquid form • The most common solvent – ionic compounds dissolve readily
• Acid, base, neutral pH depending on solutes • Conducts electricity if salts are dissolved
Geographic Loca3on or type
Mangroves occur along coastlines in tropical climates
Geographic Loca3on or type
Wetlands occur at different la3tudes
Zones -‐ ocean
• Different depths have different characteris3cs
• Ocean depths range to 5 miles
• Energy sources range from solar to volcanic
Zones -‐ Lake Different depths have different characteris3cs. Light, oxygen levels, and temperature all determine plant, animal, decomposer communi3es
Light
While water depth determines how much light gets through, turbidity is also a huge factor. Turbidity of a water body can be impacted by natural and human ac.vity, and turbidity impacts water ecosystems.
Temperatures change seasonally, changing water density
Ocean temperatures: la3tude and currents
Arrows show the direc.on of water flow. The white current is the Gulf Stream, which flows along the East Coast of NA, across the Atlan.c Ocean, and warms Western Europe.
Presence of oxygen, nutrients, salt
Geological factors – rock, soil
Rare Earth metal deposits
Sea sediment Jasper
Human Impact • Chemicals – – Fossil fuel combus.on biproducts – Manufacturing effluent – N2 and PO4 Fer.lizersà eutrophism, algal blooms – Herbicides, pes.cides, pH
• Sediment – Land management – Forest management (or mismanagement)
• Fecal mader – human and animal waste • Garbage • Temperature – Manufacturing effluent – Global warming
Biosphere
• Tolerance for environmental condi.ons • Limi.ng factors – temperature, nutrients, space, oxygen
Community proper.es
• Primary produc.vity • Biodiversity – species richness • Abundance – # of organisms of a species • Complexity – # of species at each trophic level – The more complex the food web, the more resistant it is to disturbance
Communi.es in Transi.on
Primary Succession – life has never been there and it starts Secondary Succession – life was destroyed and returns Climax Community – life has developed complexity, abundance, and can develop no further
Species and Niche
Indicator species -‐ reflect living condi.ons
Keystone species – play a significant role; other species depend on them
Exo.c species – compete with na.ves
NICHE – an organism’s role in the community Generalists – can survive in a wide range of habitats Specialists – survive in only a narrow range of habitats
LAW OF COMPETITIVE EXCLUSION
No two species can occupy the same niche and compete for the same resources.
This will lead to either: – Ex.nc.on of one species – Behavior change • Temporal isola.on • Geographic isola.on • Symbio.c coopera.on
– Gene.c change: Adapta.on
Adapta.on -‐ Natural Selec.on
• Gene.c traits that survive in harsh condi.ons are passed onto offspring
• When members of a popula.on are isolated by (ecologic or geographic) barriers, they can change enough to become a separate species
Popula.on Change
• J-‐curve -‐ exponen.al growth without limit • S-‐curve -‐ growth that responds to limits • Doubling .me – 70 / rate of growth • Oscilla.on – cycles of growth and decline • Species Type – r-‐adapted: high reproduc.on, high mortality – K-‐adapted: few offspring, larger, live longer
Factors that impact popula.ons
• Fer.lity • Mortality • Life expectancy • Emigra.on • Abio.c factors – human impact on Earth Systems – natural disasters
• Stress and crowding • Conserva.on / Restora.on efforts