RU BL 410 - Lecture Notes (8 pages)

Previewing pages 1, 2, 3 of 8 page document View the full content.
View Full Document

Lecture Notes



Previewing pages 1, 2, 3 of actual document.

View the full content.
View Full Document
View Full Document

Lecture Notes

21 views


Pages:
8
School:
Regis University
Course:
Bl 410 - AQUATIC ECOLOGY
Unformatted text preview:

Lakes Ponds Lake Pond body of water in one basin with realtively little flow Limnology study of lake ecology Lentic system more still fresh water system Lacustrine of around lake pond limno lake Lake Zones Euphotic zone where light can support photosynthesis Littoral zone where attached macrophytes and periphyton can grow euphotic periphery Limnetic zone Open water no macrophytes Lake Strata Layers Epilimnion warm upper layer in a lake Much sunlight affected by wave energy lower nutrients high dO2 Hypolimnion cool lower layer in a lake Little sunlight little affected by waves higher nnutrients high or low no dO2 Thermocline Metalimnion Epilimnion Hypolimnion Lake Turnover Stratification thermal layering with a distinct epi hypolimnion Temperate lakes may mix in the fall spring turnover destratification Wind can keep deep lakes from stratifying surface warms surface cools Lake Turnover Turnover ensures hypolimnion oxygenation and increases nutrients in epilimnion Permanently stratified lakes e g deep tropical may have anoxic hypolimnions also can build up H2S in hypolimnion Turnover in permanently stratified lakes can lead to fish kills or eutrophication Fetch Fetch the distance over which winds blow over a lake Greater fetch more larger waves and more mixing less likely to be stratified wind direction Lake Primary Production Emergent Macrophytes Littoral mostly flowering plants Submerged Macrophytes Littoral mostly flowering plants and green algae Periphyton Littoral mostly green algae diatoms and cyanobacteria Phytoplankton Limnetic and Littoral mostly green algae diatoms and cyanobacteria limnetic phytoplankton littoral emergent macrophytes littoral submerged macrophytes Allochthonous Inputs In most lakes some nutrients come from surrounding terrestrial environments and tributary streams Given low flows most particulate organic matter POM sinks in lakes ponds Many lakes with substantial allochthonous inputs have macroinvertebrate shredders and collectors like in streams but usually different species Littoral Zone Food Web runoff or groundwater entry leaf litter periphyton macrophytes conditioning microbial colonization bacteria coarse particulate fungi organic matter CPOM grazing grazing fishes insects crustaceans shredding dissolved organic compounds DOC fine particulate organic matter FPOM insects crustaceans collecting predatory predatory fishes insects crustaceans insects crust nematodes annelids bacteria fungi Limnetic Euphotic Food Web phytoplankton dissolved organic compounds DOC phytobacteria microzooplankton phytoplanktivorous grazing zooplankton fishes bacteria predatory zooplankton predatory fishes Lake Grazing Zooplankton Cladocerans Copepods Cladocerans Daphnia Copepods Lake Predatory Zooplankton Cladocerans Insect Larvae midge larvae Ghost Midge Larva Chaoborous Cladocerans Leptodora Polyphemus Insect Larvae and Decapods Insect Larvae Many insect larvae are aquatic esp common in littoral dragonflies damselflies mayflies black flies mosquitoes horse flies Crustaceans crayfishes in North America Lake Fishes North Amercan Fishes 979 native freshwater species 82 exotic species 50 taxonomic families Arbitrarily divided into coolwater and warmwater ichthyofauna Coolwater water never warmer than 22 C Warmwater water gets above 22 C Broad Lake Categories Oligotrophic Lakes deep cool nutrient poor lakes Usually stratified Mountain lakes Eutrophic Lakes shallow warm nutrient rich lakes Often not stratified Shallow Ponds Oligotrophic Eutrophic continuum Cultural Eutrophicaltion anthropogenic nutrient P N input can cause anoxia Broad Lake Categories eutrophic oligotrophic Cultural Eutrophication Macrophyte vs Algal Systems Macrophyte systems Macrophytes and cladocerans more common Cladocerans graze algae and macrophytes retain nutrients in tissues Lower free nutrients in water Water clear Algal systems Algae more common Nutrients rapidly cycled through algae Higher free nutrients in water Water turbid Nutrient increase removal of macrophytes or increase in planktiovorous fish can shift from a macrophyte to an algal system North American Great Lakes Gouged out by glaciers Experienced many introduced species S Great lakes experienced much pollution Aral Sea Freshwater Lake Its water input was diverted by the Soviets to irrigate parts of Kazakstan As an arid environment water levels fell and salinity increased tremendously Aral Sea Differences in Tropical Lakes Bacterial and fungal decomposition of allochthonous material is more rapid Fewer aquatic insects Fishes and in some places decapod crustaceans serve as the major shredders collectors and grazers If deep may be permanently stratified Lake Victoria Many native cichlid fish species 300 First some cultural eutrophicaltion then intro of Nile perch Lates nilotica around 1960 Only 100 cichlid species still extant


View Full Document

Access the best Study Guides, Lecture Notes and Practice Exams

Loading Unlocking...
Login

Join to view Lecture Notes and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Lecture Notes and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?