Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mud manifests history of clear water in murky Minnesota duck depot Lake Christina

28.03.2012
Implications for ducks, fish, and landscape management

During peak migration days in the early 1900s, tens of thousands of canvasback ducks could be seen floating and diving on Minnesota's Lake Christina. Since midcentury, changes to the lake have diminished this grand, iconic spectacle.

Restoring it will require both top-down control of life in the lake, and bottom-up management of the surrounding landscape. So says a team of Minnesota scientists calling on extensive modern records and 200 years of history trapped in sediment, in a report released online last week in the journal Ecological Applications.

"Lake Christina is very important for the region culturally, and ecologically," said Will Hobbs, a scientist at the Science Museum of Minnesota and lead author of the report. "The lake is a significant stop-over for waterfowl migrating along the Mississippi Flyway, but it has been compromised since the 1950s."

Lake Christina has an unusually long history of management, offering a unique opportunity to study the effects of biological manipulations and management.

In the 1950s, the lake's clear water darkened to a green algal soup. By calibrating sediment cores to 25 years of modern records, the research team learned that Lake Christina had had clear waters for 100 years prior to European settlement in the late nineteenth century – the clear water was a stable state, and not an historical aberration. But now the lake is in a stable, murky state.
Managers have been struggling to regain clear waters in the lake for migrating waterfowl, particularly the big, rusty-headed canvasbacks. The ducks need a healthy meal of submerged aquatic plants to fuel their journey, but the dense algae blocks out so much sunlight that underwater plants like sago pondweed and wild celery can't grow.

A similar loss of submerged aquatic plants has developed at the canvasbacks' major historic wintering grounds on Chesapeake Bay.

"Life is not easy for a duck. You need those areas where you can stop and rest – large open expanses of shallow water with readily available food," said author Mark Hanson, a research scientist with the Minnesota Department of Natural Resources.

Two factors led to the clouding of the waters: an influx of nutrients from agriculture fed the algae, and a dam built in 1936 led to a fall in the population of tiny, algae-eating zooplankton. The dam doubled the depth of the lake, from two feet to four, allowing fish that eat zooplankton to survive the winter, and thrive.
To make the lake attractive for ducks, managers killed most of the fish in 1965, 1987, and 2003, each time achieving only temporary success. Within a decade, the fish recovered, and the algae followed.

Restoration of wetlands surrounding the lake has not, as yet, met hopes for lowered nutrient levels.

"It's very difficult to get the nutrients out of the lake," said author Kyle Zimmer, an associate professor at the University of St. Thomas who has studied the fish at Lake Christina for several years. "We know from the literature that these things can take time, and maybe top-down, active management allows that time, or at least simulates the outcome we want, even if a self-maintained stable state is not achieved."

Managers walk a fine line, balancing short and long term needs, and balancing the interests of ducks and duck hunters at Lake Christina with those of recreational anglers. This fall, top-down management will include a series of pumps and pipes installed to draw-down the water level, mimicking the natural winter fish kill.

"The study presents compelling evidence that, in the long run, managers need to focus on strategies that target landscapes, not just the food webs in the lakes themselves – bearing in mind that the short term is also important," said Hanson. "The people that live here today are very much in this culture of ducks and migratory water birds, and the incredible history around them. When we get all sectors working on lake ecology together, that's a very productive basis for the future."

"A 200-year perspective on alternative stable state theory and lake management from a biomanipulated shallow lake" was published online, ahead of print, on 19 March 2012. It is slated for the July edition of Ecological Applications. doi: 10.1890/11-1485.1. Click for abstract. To obtain a pdf, or associated images, contact Liza Lester.

Students at North Dakota State University, in collaboration with the Minnesota Department of Natural Resources, contributed significant contemporary data to this project from long term monitoring efforts at Lake Christina.

The Ecological Society of America is the world's largest community of professional ecologists and the trusted source of ecological knowledge. ESA is committed to advancing the understanding of life on Earth. The 10,000 member Society publishes five journals, convenes an annual scientific conference, and broadly shares ecological information through policy and media outreach and education initiatives. Visit the ESA website at http://www.esa.org or find experts in ecological science at http://www.esa.org/pao/rrt/.

Liza Lester | EurekAlert!
Further information:
http://www.esa.org

More articles from Ecology, The Environment and Conservation:

nachricht Global threat to primates concerns us all
19.01.2017 | Deutsches Primatenzentrum GmbH - Leibniz-Institut für Primatenforschung

nachricht Reducing household waste with less energy
18.01.2017 | FIZ Karlsruhe – Leibniz-Institut für Informationsinfrastruktur GmbH

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland

19.01.2017 | Earth Sciences

Not of Divided Mind

19.01.2017 | Life Sciences

Molecule flash mob

19.01.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>