Loss of “lake lawnmowers” leads to algae blooms
Unprecedented algae growth in some lakes could be linked to the decline of water
calcium levels and the subsequent loss of an important algae-grazing organism
that helps keep blooms at bay.
Daphnia—also known as water fleas—act like microscopic lawnmowers in
lakes, feeding on algae and keeping it in check. However, without sufficient
calcium, these water fleas cannot reproduce.
“When water calcium levels get low and
Daphnia populations decrease in
any lake, algal growth goes unchecked and blooms can occur,” says lead author
and biology doctoral student Jennifer Korosi. “Losing an important grazer like
these water fleas has a domino effect that leads to other water quality
problems.”
Declining calcium concentrations in some lakes, which is linked to acid
deposition and logging, has only recently been identified as a serious
environmental problem in North America and Europe.
By studying microscopic fossils and other indicators preserved in a lake
sediment core from Lake George (Nova Scotia), the Queen’s research team found
that algal production remained relatively constant throughout the last century
until around1990 when the levels tripled. The increase in algae directly
coincided with the decrease of
Daphnia in the lake.
“Algal blooms appear to be increasing in many lake regions,” says biology
professor John Smol, Canada Research Chair in Environmental Change, and previous
winner of the Natural Sciences and Engineering Research Council of Canada (NSERC)
Herzberg Gold Medal as Canada’s top scientist. “Decreasing calcium levels appear
to be one more factor that can exacerbate this problem. This is particularly
worrisome given that many other stressors, such as climate warming and
fertilizer runoff, are already contributing to the production of nuisance algal
blooms. This is one more nail in the coffin.”
Other members of the research team include PhD candidate Joshua Thienpont and
undergraduate student Samantha Burke. Funding for the research comes from NSERC.
These findings will be published in the next issue of the prestigious
international journal
Proceedings of the Royal Society B.
PLEASE NOTE: A PDF
copy of the study can be obtained from the
Proceedings of the Royal Society website, or contact Dr. John Smol at
smolj@queensu.ca for a copy.
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Contact information for authors:
Jennifer B. Korosi
Paleoecological Environmental Assessment and Research Lab
(PEARL)
Department of Biology, Queen's University
116 Barrie St., Kingston, ON, Canada, K7L 3N6
Telephone: 613--533--6000 ext:77380
Email: jennifer.korosi@queensu.ca
|
Samantha Burke
Paleoecological Environmental Assessment and Research Lab
(PEARL)
Department of Biology, Queen's University
116 Barrie St., Kingston, ON, Canada, K7L 3N6
|
Joshua R.
Thienpont
Paleoecological Environmental Assessment and Research Lab
(PEARL)
Department of Biology, Queen's University
116 Barrie St., Kingston, ON, Canada, K7L 3N6
Telephone: 613--533--6000 ext:77380
Email: joshua.thienpont@queensu.ca |
John P. Smol
Paleoecological Environmental Assessment and Research Lab (PEARL)
Department of Biology, Queen's University
116 Barrie St.
Kingston, ON, Canada, K7L 3N6
Telephone: 613--533--6147
Email: smolj@queensu.ca
|
