Lecture today in lab

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Lecture today in lab

• 3pm, room 224 Biodiversity
• Thursday lab- room 1220 Bioscience, 2pm

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Lake formation and succession
?16 45.04S, 70 11.35 W
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Outline

• How lakes are made
• 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

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Temperature and CO2 history of the world- the
last 400,000 years, cycles of glaciation
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Causes of glaciation cycles
Milankovich cycles
Obliquity cycles
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The last 20,000 years

• http//www.ncdc.noaa.gov/paleo/pollen/viewer/webvi
  ewer.html

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The last 2,000 years

The little ice age
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Present day glaciersE.C. Pielou After the Ice Age
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I. Ice Dam Lake (Proglacial) e.g. Lake Agassiz
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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.
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Cooling event caused by draining Agassiz
Younger Dryas
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Thermohaline circulation
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II Formed by Depressions e.g. Kettle Lakes
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III Formed by Scour e.g. Finger Lakes (NY)
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Biological imprint of glaciation

• dispersal through proglacial lakes
• colonization from different Pleistocene refuges

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Different refuge areas in Eastern North
AmericaStemberger 1995 Canadian J. of Fisheries
and Aquatic Sciences 522197
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Effects of post-glacial dispersal on present
distributionsThum and Stemberger unpublished
Vicariance
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Some species have dispersed since de-glaciation
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Genetic diversity in Artic Grayling related to
dispersal corridorsStamford and Taylor 2004
Molecular Ecology 131533
Yukon River
Nahinni River
Brooks Range
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River Formed Lakes Oxbow lakes
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Tectonic Lakes e.g. Mono Lake, CA
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Volcanic Lakes Mount St. Helens, Oregon
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Organism Lakes e.g. Beaver Ponds
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Sink Holes e.g. Beaver Ponds
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Lake Death
Raymond Lindeman. 1942. The trophic-dynamic
aspect of ecology. Ecology 23399-418
Those not busy being born are busy dying
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(No Transcript)
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Raymond Lindeman. 1942. The trophic-dynamic
aspect of ecology. Ecology 23399-418
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Engstrom et al. 2000. Chemical and biological
trends during lake evolution in recently
deglaciated terrain. Nature 408 161-166.
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Things you should know (aka learning objectives)

• Most lakes are made by glaciers
• Glaciers happen because of changes in earths
  orbit
• Lake succession reveals the role of death and
  decay
• Lakes become more productive over time until
  theyre not