Lecture today in lab 3pm, room 224 Biodiversity Thursday lab- room 1220 Bioscience, 2pm
Lake formation and succession 16 45.04S, 70 11.35 W
Outline How do lakes die? How lakes are made Drain Fill in Glacial lake (~74% of lakes) Biological imprint on landscape River formed lakes Tectonic lakes Coastal lakes Volcanic lakes Organism lakes Sink holes How do lakes die? Drain Fill in
Temperature and CO2 history of the world- the last 400,000 years, cycles of glaciation
Causes of glaciation cycles Milankovich cycles Obliquity cycles
The last 20,000 years http://www.ncdc.noaa.gov/paleo/pollen/viewer/webviewer.html
The last 2,000 years { The little ice age
Present day glaciers E.C. Pielou After the Ice Age
I. Ice Dam Lake (Proglacial): e.g. Lake Agassiz
I. Ice Dam Lake (Proglacial): e.g. Lake Agassiz Garry Clarke et al. 2003. Super lakes, megafloods, and abrupt climate change. Science 301: 922-923.
Cooling event caused by draining Agassiz Younger Dryas
Thermohaline circulation
II: Formed by Depressions: e.g. Kettle Lakes
III: Formed by Scour: e.g. Finger Lakes (NY)
Biological imprint of glaciation dispersal through proglacial lakes colonization from different Pleistocene refuges
Different refuge areas in Eastern North America Stemberger 1995 Canadian J. of Fisheries and Aquatic Sciences 52:2197
Effects of post-glacial dispersal on present distributions Thum and Stemberger unpublished Vicariance
Some species have dispersed since de-glaciation
Genetic diversity in Artic Grayling related to dispersal corridors Stamford and Taylor 2004 Molecular Ecology 13:1533 Yukon River Nahinni River Brooks Range
River Formed Lakes: Oxbow lakes
Tectonic Lakes: e.g. Mono Lake, CA
Volcanic Lakes: Mount St. Helens, Oregon
Organism Lakes: e.g. Beaver Ponds
Sink Holes: e.g. Beaver Ponds
Lake Death Those not busy being born are busy dying Raymond Lindeman. 1942. The trophic-dynamic aspect of ecology. Ecology 23:399-418 Those not busy being born are busy dying
Raymond Lindeman. 1942. The trophic-dynamic aspect of ecology Raymond Lindeman. 1942. The trophic-dynamic aspect of ecology. Ecology 23:399-418
Engstrom et al. 2000. Chemical and biological trends during lake evolution in recently deglaciated terrain. Nature 408: 161-166.
Things you should know (aka learning objectives) Most lakes are made by glaciers Glaciers happen because of changes in earth’s orbit Lake succession reveals the role of death and decay Lakes become more productive over time until they’re not