. Earth Science News .
FLORA AND FAUNA
Invasive Mussels Causing Massive Ecological Changes In Great Lakes

File image.
by Staff Writers
Ann Arbor MI (SPX) Apr 15, 2011
The ongoing spread of non-native mussels in the Great Lakes has caused "massive, ecosystem-wide changes" throughout lakes Michigan and Huron, two of the planet's largest freshwater lakes, according to a new University of Michigan-led study.

The blitzkrieg advance of two closely related species of mussels-the zebra and quagga-is stripping the lakes of their life-supporting algae, resulting in a remarkable ecological transformation and threatening the multibillion-dollar U.S. commercial and recreational Great Lakes fisheries.

Previous studies have linked the mussels to far-reaching changes in Lake Michigan's southern basin. Now a paper by two University of Michigan ecologists and a colleague shows that the same dramatic changes are occurring in northern Lake Michigan and throughout Lake Huron, as well.

"These are astounding changes, a tremendous shifting of the very base of the food web in those lakes into a state that has not been seen in the recorded history of the lakes," said Mary Anne Evans, lead author of a paper scheduled for publication in the April 15 edition of the journal Environmental Science and Technology. "We're talking about massive, ecosystem-wide changes."

Evans is a research fellow at the U-M School of Natural Resources and Environment. The other authors are Donald Scavia, director of U-M's Graham Environmental Sustainability Institute, and Gary Fahnenstiel, senior ecologist at the National Oceanic and Atmospheric Administration's Great Lakes Environmental Research Laboratory.

Because the changes are so profound and are happening so rapidly, the authors recommend that Great Lakes management agencies review and perhaps revise their policies so they can respond more quickly.

"New strategies for managing the lakes are urgently needed. Ecological changes that formerly occurred over decades are now happening in just a few years, so we need to adapt our management policies to this new reality," Scavia said.

This recommendation is especially relevant in the context of the current review of the Great Lakes Water Quality Agreement by the International Joint Commission, Scavia said. Through the IJC, the United States and Canada jointly manage the Great Lakes.

Though the zebra mussel is better known to the public, over the past decade it has largely been overshadowed by the quagga mussel, which can thrive far from shore in deep, mud-bottomed waters. Each of the fingernail-size quagga mussels filter about a quart of water a day, and billions of them now blanket the bottoms of lakes Michigan and Huron down to depths of nearly 400 feet.

They feed on algae, including single-celled plants called diatoms that are encased in glass-like shells made of silica, which the diatoms extract from lake water. Until recently, the diatoms "bloomed" each spring in the Great Lakes, and the level of silica in upper lake waters dropped as diatoms built their protective shells, then sank to the lake bottom, taking the silica with them.

The drop in silica levels due to the spring diatom bloom, known as the seasonal drawdown, has long been used as an indicator of overall algal production in the Great Lakes.

Reviewing records of silica levels in lakes Michigan and Huron collected over the past 30 years by the Environmental Protection Agency, Evans and her colleagues found that algal production throughout the two lakes was about 80 percent lower in 2008 than it had been in the 1980s.

In Lake Michigan, the decrease in the seasonal drawdown coincided with an explosion in the quagga mussel population and its expansion to greater depths, which began in 2004. The same changes occurred a few years earlier in Lake Huron, where quagga mussels greatly increased in abundance between 2000 and 2003.

"For years, all the talk was about the zebra mussels. And then its close cousin comes in, the little quagga mussel, and wreaks even more havoc on these huge offshore systems," said NOAA's Fahnenstiel.

"These changes are unprecedented," he said. "In terms of algal abundance and water clarity, lakes Michigan and Huron are now similar to Lake Superior."

By filtering out the algae, the mussels are robbing other organisms of the food they need to survive. Of particular concern is the plight of Diporeia, a tiny shrimplike creature that was one of the pillars supporting the base of the Great Lakes food web.

Nearly every fish species in the Great Lakes relies on Diporeia at some point in its life cycle. But Diporiea populations have crashed in lakes Michigan and Huron, and the change is already impacting Great Lakes commercial fisheries and the sport-fishing enterprise.

"The big question now is how large the quagga mussel population will get," Evans said. "And when it gets as big as it can get, will it stay at that level or will it die back because it has decimated its own food supply? We don't really know what to expect at this point."



Share This Article With Planet Earth
del.icio.usdel.icio.us DiggDigg RedditReddit
YahooMyWebYahooMyWeb GoogleGoogle FacebookFacebook



Related Links
Sustainability at the University of Michigan
Darwin Today At TerraDaily.com



Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News


FLORA AND FAUNA
Circadian Rhythms Spark Plants' Ability To Survive Freezing Weather
East Lansing, MI (SPX) Apr 15, 2011
span class="NL"> a href="http://www.msu.edu" class="highlight">Michigan State University /a> br> /span> Just as monarch butterflies depend on circadian cues to begin their annual migration, so do plants to survive freezing temperatures. All living things - humans, animals, plants, microbes - are influenced by circadian rhythms, which are physical, mental and behavioral changes that follo ... read more







FLORA AND FAUNA
Clinton vows full support for disaster-hit Japan

Fukushima Cold In 9 Months; Robots To Explore Reactors

Clinton visits Japan as US disaster relief warms ties

Japan nuclear firm sees 'cold shutdown' in 6-9 months

FLORA AND FAUNA
Researchers Discover The Cause Of Irradiation-Induced Instability In Materials Surfaces

Eco-Friendly Treatment For Blue Jeans Offers Alternative To Controversial Sandblasting

Japan's TEPCO pours radiation-absorbing mineral in sea

Ultra-Fast Magnetic Reversal Observed

FLORA AND FAUNA
Ocean Front Is Energetic Contributor To Mixing

Sizzling, landlocked Madrid gets cool new 'beach'

Want to cut shipping costs? Then go fly a kite

Sushi bars in Paris adjust to life after Fukushima

FLORA AND FAUNA
West Antarctic Warming Triggered By Warmer Sea Surface In Tropical Pacific

Arctic Sea Ice Flights Near Completion

ESA Arctic Ice Campaign Takes Off

Sand Drift Explained

FLORA AND FAUNA
New Citrus Variety Released By Uc Riverside Is Very Sweet, Juicy And Low-Seeded

Japan asks Brazil to ease food import rules

Vegetarian magazine defends meat photos

Half EU states negative on GM foods

FLORA AND FAUNA
Increasing activity at Philippine volcano

Hundreds of aftershocks worsen Japan's quake trauma

One year on, Iceland volcano sleeps, but world still quakes

An Electric Yellowstone Makes For Super Visuals

FLORA AND FAUNA
Chinese aid good for Africa: ministers

Senegal opens Chinese-built theatre

UN should not take sides in I.Coast: Medvedev

Sierra Leone investigates a mining land acquisition

FLORA AND FAUNA
Scripps Research Scientists Identify Mechanism Of Long-Term Memory

Are Your Values Right Or Left? The Answer Is More Literal Than You Think

Negative Image Of People Produces Selfish Actions

Single 'ancestor' language theorized


The content herein, unless otherwise known to be public domain, are Copyright 1995-2010 - SpaceDaily. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement