Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Annual Tahoe Report Says Asian Clam Invasion Is Growing Fast

20.08.2009
Released yesterday, UC Davis' annual Lake Tahoe health report describes a spreading Asian clam population that could put sharp shells and rotting algae on the spectacular mountain lake's popular beaches, possibly aid an invasion of quagga and zebra mussels, and even affect lake clarity and ecology.

"Our collaborative UC Davis and University of Nevada, Reno, science team found up to 3,000 Asian clams per square meter at locations between Zephyr Point and Elk Point in the southeastern portion of the lake," said John Reuter, associate director of the UC Davis Tahoe Environmental Research Center.

"Those are high numbers, especially when compared to the few isolated, dead shells we found back in 2002 when the Asian clam was first reported. We already see associated environmental effects from the clams today, and we are concerned that they might spread.”

Issued annually since 2007, the "Tahoe: State of the Lake Report" is intended to give the public a better understanding of the changes occurring in Lake Tahoe on a year-to-year basis and to place current conditions within a historical perspective. It summarizes tens of thousands of scientific observations of lake weather, water conditions and aquatic life made since 1900. It is compiled by the research scientists of the UC Davis Tahoe Environmental Research Center.

The dime-sized Asian clam (Corbicula fluminea) that is the researchers’ top concern this year probably has been in the lake for only 10 years, but it is already replacing native pea clams in lake sediments. In the areas where they are most numerous, Asian clams comprise almost half of the benthic, or sediment-dwelling, organisms, the report says.

What's more, in the beds of Asian clams, a green filamentous alga, Zygnema, is thriving. The report says the algae probably are being nourished by the high concentrations of nutrients excreted by the clams. Dead Zygnema clumps become a nuisance when they wash onto beaches and decompose. “This moves Lake Tahoe further away from its desired pristine condition,” Reuter said.

Another worry: UC Davis and UNR researchers say accumulations of Asian clams might foster the invasion of two other damaging species: quagga and zebra mussels, which radically alter ecosystems by consuming enormous amounts of the tiny algae that are the base of lake food chains and outcompeting the native bottom-dwelling species. The mussels are also feared for their ability to encrust piers and boat hulls, and have already caused millions of dollars in damage in the Great Lakes by blocking intake pipes at water and power plants.

Zebra and quagga mussels are spreading west by hitchhiking on boat hulls, and a comprehensive program of public education and boat inspections has been established by resource managers to try to keep them out of Lake Tahoe. While Asian clams are not expected to become the colonizing monster that quagga and zebra mussels are, they may make lake waters more hospitable to the problem mussels by concentrating calcium, an essential nutrient.

In addition to the Asian clam concerns, many other trends and observations are described in the 64-page State of the Lake Report. They include:

The lake’s clarity was unchanged from the previous year: The Secchi depth was 69.6 feet.
The long-term warming trend seen since 1970 continued, with warmer nights and lake waters, fewer cold days and less precipitation falling as snow. However, 2008 was a cold year, with the greatest number of freezing days since the early 1990s.
It was another dry year -- the 12th driest year on record. While the historical average annual precipitation is 31.6 inches, in 2008 only 19.3 inches of precipitation fell.
In 2008, Lake Tahoe mixed all the way to the bottom at the mid-lake station. This was the second successive year of deep mixing. Complete mixing during two or more successive years has only occurred three times since 1973. Mixing matters because it circulates nutrients and other material from the lake’s depths to the surface water and returns oxygen to the deep water.

The "Tahoe: State of the Lake Report 2009" is free and available online at http://terc.ucdavis.edu.

About the Tahoe Environmental Research Center

The Tahoe Environmental Research Center (TERC) is dedicated to research, education and public outreach on lakes and their surrounding watersheds and airsheds. Lake ecosystems include the physical, biogeochemical and human environments, and the interactions among them. The center is committed to providing objective scientific information for restoration and sustainable use of the Lake Tahoe Basin.

About UC Davis

For 100 years, UC Davis has engaged in teaching, research and public service that matter to California and transform the world. Located close to the state capital, UC Davis has 31,000 students, an annual research budget that exceeds $500 million, a comprehensive health system and 13 specialized research centers. The university offers interdisciplinary graduate study and more than 100 undergraduate majors in four colleges — Agricultural and Environmental Sciences, Biological Sciences, Engineering, and Letters and Science — and advanced degrees from six professional schools — Education, Law, Management, Medicine, Veterinary Medicine and the Betty Irene Moore School of Nursing.

John Reuter | EurekAlert!
Further information:
http://www.ucdavis.edu

More articles from Ecology, The Environment and Conservation:

nachricht Successful calculation of human and natural influence on cloud formation
04.11.2016 | Goethe-Universität Frankfurt am Main

nachricht Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide

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: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>