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 Minimized water consumption in CSP plants - EU project MinWaterCSP is making good progress
05.12.2017 | Steinbeis-Europa-Zentrum

nachricht Jena Experiment: Loss of species destroys ecosystems
28.11.2017 | Technische Universität München

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: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

Im Focus: Virtual Reality for Bacteria

An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications

Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...

Im Focus: A space-time sensor for light-matter interactions

Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.

The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...

Im Focus: A transistor of graphene nanoribbons

Transistors based on carbon nanostructures: what sounds like a futuristic dream could be reality in just a few years' time. An international research team working with Empa has now succeeded in producing nanotransistors from graphene ribbons that are only a few atoms wide, as reported in the current issue of the trade journal "Nature Communications."

Graphene ribbons that are only a few atoms wide, so-called graphene nanoribbons, have special electrical properties that make them promising candidates for the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

Blockchain is becoming more important in the energy market

05.12.2017 | Event News

 
Latest News

Making fuel out of thick air

08.12.2017 | Life Sciences

Rules for superconductivity mirrored in 'excitonic insulator'

08.12.2017 | Information Technology

Smartphone case offers blood glucose monitoring on the go

08.12.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>