Species, Populations, Communities Interactions in Water Ecosystems

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Our job: Provide comprehensive input about: Physical, chemical, and biological properties of water environments Species interactions Population dynamics Human impacts

water ecosystems Marine (Ocean) / Reefs Mangroves / swamps Estuaries / Wetlands / Lagoons River / Riparian Lake Ice / Glaciers

Biological Species and Niche Community Properties Environmental Pressures Population Dynamics

Properties 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

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 activity, and turbidity impacts water ecosystems.

Arrows show the direction of water flow. The white current is the Gulf Stream, which flows along the East Coast of NA, across the Atlantic Ocean, and warms Western Europe.

Rare Earth metal deposits Sea sediment Jasper

Human Impact Chemicals – – Fossil fuel combustion biproducts – Manufacturing effluent – N 2 and PO 4 Fertilizers  eutrophism, algal blooms – Herbicides, pesticides, pH Sediment – Land management – Forest management (or mismanagement) Fecal matter – human and animal waste Garbage Temperature – Manufacturing effluent – Global warming

Biosphere Tolerance for environmental conditions Limiting factors – temperature, nutrients, space, oxygen

Community properties Primary productivity 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

Communities in Transition

Species and Niche 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: – Extinction of one species – Behavior change Temporal isolation Geographic isolation Symbiotic cooperation – Genetic change: Adaptation

Adaptation - Natural Selection Genetic traits that survive in harsh conditions are passed onto offspring When members of a population are isolated by (ecologic or geographic) barriers, they can change enough to become a separate species

Population Change J-curve - exponential growth without limit S-curve - growth that responds to limits Doubling time – 70 / rate of growth Oscillation – cycles of growth and decline Species Type – r-adapted: high reproduction, high mortality – K-adapted: few offspring, larger, live longer

Factors that impact populations Fertility Mortality Life expectancy Emigration Abiotic factors – human impact on Earth Systems – natural disasters Stress and crowding Conservation / Restoration efforts