Biology 3850A Aquatic EcosystemsTime: Monday/Wednesday/Friday 10:00-10:50 AM,Jan 06-Apr 16, 2010

Place: B 775

Instructor: Dr. Joseph B. Rasmussen—office hours by appt.Professor, Department of Biological Sciences Canada Research Council Chair in Aquatic Ecosystems

Office: WE1050 WESBPhone: (403) 382-7182Email: joseph.rasmussen@uleth.ca

Lab Assignments—8% eachI : The watershed and stream dynamics—II. Morphometry and dynamics of lakes—III: Primary production: calculation of 1o productivityIV. Phosphorus loading models and eutrophicationV. Secondary producers: fish productivity and management

Aquatic Ecosystems

Definition of Eco-system

System –many components functionally interactingmost of these components are living organismsgenetically unique and always changing (evolution)

Composed of the biological community (many species populations)Interacting with the physical world

Aquatic and terrestrial ecosystems are very different in their physical character and this has a major impact on the way nutrients cycleas well as on the types of organisms that are found there.

-Key physical processes in aquatic systems—flow and sedimentation (mud)-flow brings nutrients into the system from the surrounding landscape (watershed), and cause them to be lost as well.

Next: people who have played a major role in the development of Aquatic Ecosystem concepts

Stephen Forbes,1887 “The Lake as a Microcosm”

Founder of the Illinois Natural History Survey

Well known for his work on aquatic insects and fishes, and for his description of aquatic food chains in small lakes and ponds.

His writings stressed the isolated autonomous character, the separateness of lakes/ponds from the surrounding landscape.

August Thienemann Einar Naumann

Founders of the International Association of Theoretical and Applied Limnology

The Productivity of Waters and their Nutrient status

Edward Birge and Chancey Juday sampling zooplankton in Lake Mendota, Wisconsin

The thermal structure and energy budget of lakes, the thermocline

G. Evelyn HutchinsonYale University

Trophodynamic processesNutrient cycling in lakes

Charles S. Elton,

•Fluctuations in numbers of animals

•The food pyramid and the trophic web

•also wrote the first book on the ecological impacts of exotic species invasions

Eugene P. Odum, 1913 - 2002.

Odum is widely considered to be the “Father” of ecosystem ecology

Pioneered research into the use of radioactive tracers and dissolved oxygen cycles to study primary production in aquatic ecosystems.

Author of Fundamentals of Ecology, 1953

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Daily cycle in dissolved oxygen (flow weighted average) at Pavan study site

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Daily cycle in dissolved oxygen (flow weighted average) at Pavan study site

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Raymond Lindeman 1915-42

•Ph.D 1941 from the University of Minnesota

•died at age 27 but is still remembered for “The trophic-dynamic aspect of ecology, Ecology 23: 399-418)” from his thesis work on Cedar Bog, Minnesota.

•This paper has since become the foundation for research on the flow of energy in plant and animal communities.

Cedar Bog Lake

energy flow through the foodweb could be analyzed by dynamic models

Energetic efficiency of trophic levels

Aquatic Ecosystems provide key resourcesE.g. fish, waterfowl, rice

Ecosystem services that freshwater ecosystems provide•Water supply for drinking, agriculture and industry•Transport•Water storage•Hydroelectric power•Assimilation of pollutants•Recreation•Nutrient transport for fisheries

•Ecosystem services are economically valuable services provided “free” by natural ecosystems. By free we mean either at no cost or at a cost well below that of a manufactured substitute. They are hard to place a value on.

Transportation of people and goods

Fouling of beaches by logging operations

Dams and wiers for hydroelectric power, flood control, and water storage.

Waste disposalDomestic and industrial

Assimilative capacity

The sewage treatment plant downstream from Lethbridge

Agriculture is the biggest water user of all

Recreation

Golf courses are huge water users. The golf courses are the greenest part of Lethbridge during the summer