Aquatic Ecology

What is Ecology

Study of relationships between organisms and the

environment.

Ecologists study environmental relationships

Ecologists study:

O2 levels

Water Temps

Fish species

Plat species

Range of environmental

relationships

Indiv. ex. Zebra

Population

Community (species interactions)

Ecosystem

Landscape

Biosphere (global scale)

Ecology of individuals

Physiological and behavioral ecology.

• Emphasize the evolution of physiological and

anatomical mechanisms and behaviors.

Ecology of populations

Factors influencing population structure and process

• adaptation,

• extinction,

• distribution

Communities: Ecology of interactions.

Predation, parasitism, competition, etc.

• Emphasizes evolutionary effects of

interactions

Communities: Ecology of communities

Community ecology linked to ecology of

interactions.

• Emphasis on understanding environmental

influence on community

Ecology of ecosystems

Similar to community, but…

• Focus on processes such as energy flow and

decomposition

ex. fire

Ecology of landscapes, regions, and biosphere

-Characterised by plant species and biological characteristics

-Biosphere= Atm (air) lithosphere (earth) and hydrosphere (water)

Ecological Research!!! Three categories

 Observation

 Experimentation

 Modeling

Observation

Collection of data in

unmanipulated setting

• in situ vs ex situ

• purely descriptive OR test hypothesis

• Warbler studies: MacArthur! Predicted that the 2 species with identical ecological requirements could not coexist indefinitely

-forest canopy (nutrients from epiphytes plants)

in situ

in natural habitats

ex situ

outside of their natural habitats

New Tools: Stable Isotope

Analysis

A chemical element may have different atomic masses (isotopes).

• Proportions of isotopes vary across the environment, and this is reflected in the body tissues of organisms.

• Enables ecologists to track habitat use.

• Requires only a small blood sample.

Shows where animals are in the hierarchy of the food chain

Experimentation

Observation does not rule out that a thing is not possible

(butterfly eating an ant)

• in situ vs ex situ

• Experiments manipulate variables while holding others constant

• Test a hypothesis

Ex. Bumblebee Experiment

Bumblebee Experiment

Are bees important to the evolution of flower size?

• Observational research suggests bees prefer larger flowers

• Larger flower = more pollen transfer = more seeds produced = more larger flowers

• Hand-pollinated vs bee-pollinated

experiment

Modeling

Creation & analysis of representations of data/ideas to make predictions

• Hypothesize how a system works

• There are both conceptual and quantitative models

• Pictures & diagrams vs mathematical

ex. Trevors light fish models: predicting how siscowet lake trout

foraging habitat changes daily and

seasonally based on solar and lunar

intensity values

Climatic and Ecological Change

Many environmental changes occur over large spatial or temporal

scales.

• Davis monitored plant pollen deposited in lake sediments in the

Appalachians.

• Documented large temporal changes to nearby plant communities.

Applications: Ecology Can Inform Environmental Law and Policy

CITES – 1973 – international treaty. (Convention on International Trade in Endangered Species of Wild Fauna and Flora.)

• ESA – 1973 – United States law. (endangered species act)

Aquatic Biomes and How They Differ

Life evolved in water as it has physical and chemical properties that make it ideal.

• Stable temperature.

• Buoyancy.

• Selective forces in aquatic and terrestrial systems are different.

• Aquatic biomes classified on physical, not biological traits.

• Salinity and water movement.

• Saltwater versus freshwater (and lentic or lotic)

Saltwater versus freshwater (and lentic or lotic)

Oxygen and Light in Aquatic Biomes

Oxygen (O2) becomes a limitingresource in aquatic systems, not

water.

• Intensity and quality of light in water affects photosynthesis.

• Most (80%) of solar energy striking water is absorbed in first 10m.

• Most ultraviolet and infrared is absorbed in first few meters.

• Blue light absorbed less quickly than other visible light.

Photosynthesis in Aquatic Biomes

Examples: water plants, algae, cyanobacteria (microscopic bacteria)

Vary in their ability to use wavelengths of light.

• Light compensation point is the depth at which oxygen is produced at the same rate it is used.

• Oxygen and energy produced in shallow depths is transported throughout aquatic system by mixingof aquatic layers.

Aquatic Layers

Water column is layered by temperature – thermal stratification.

• Warm water is less dense and floats above colder, dense water.

• Warm and cold layers are separated

Selective Forces in Aquatic Systems

PRESSURE (hydrostatic) air/water and currents can be selective

forces for living things.

-in deep ocean can be very high.

-Restrict depths to which marine birds and mammals (with lungs) can go.

-Restrict depth distributions of fish with swim bladders.