Navigation Links
Spring cold snap helps with stream ecosystem research
Date:7/23/2009

OAK RIDGE, Tenn., July 23, 2009 -- A rare April freeze in 2007 provided researchers at the Department of Energy's Oak Ridge National Laboratory with further evidence that climate change could have negative effects on stream and forest ecosystems.

As warm weather arrives sooner in many parts of the nation, forest plants and trees on the banks flourish, shading the stream from sunlight and causing an overall decrease in productivity in the late spring and summer. A research paper published in this month's issue of Global Change Biology titled "Unexpected effect of climate change: Stream ecosystem responses to the 2007 spring freeze" describes how a small change in canopy cover can dramatically impact a stream.

"The study implies that the algal productivity pulse in the stream that drives the ecosystem during the spring months could be shortened with climate change if leaf-out continues to occur earlier each year," said ORNL researcher Patrick Mulholland, author of the paper. "The stream no longer gets that period of peak productivity in spring because the leaves are shading the stream when the sun angle is relatively high."

For this particular study, an Arctic air mass sent temperatures to below 28 degrees Fahrenheit for several nights in succession, freezing many of the newly emerged leaves and leaving the stream exposed to higher than normal levels of sunlight over the next several months.

This early April freeze resulted in positive effects for a well-studied East Tennessee stream and reiterated the importance of sunlight on the growth of algae, bacteria, snails and other organisms in forest streams.

Compared to typical conditions, the post-freeze conditions set in motion a chain reaction.

"Increased light levels caused a cascade of ecological effects in the stream, beginning with considerably higher growth rates during the late spring and summer months when normally low light levels severely limit stream production," said Mulholland, a member of the Environmental Sciences Division.

In this case, a freeze caused the Walker Branch stream to prosper, but an ecosystem cannot count on unexpected weather events to maintain productivity.

"The stream ecosystem cannot depend on an Arctic air mass moving in every year, killing the leaves and exposing the stream to sunlight, resulting in increased growth," Mulholland said. "It's an unpredictable weather occurrence. On the other hand, we see that early leaf emergence has become predictable and has negative effects on the stream ecosystem during the critical spring period when many stream organisms are dependent on algae for food."

Although canopy cover in the spring leads to decreased organism growth, in the autumn, bacteria and fungi decompose the leaves and grow from the nutrients, thus stimulating productivity.


'/>"/>

Contact: Emma Macmillan
macmillanee@ornl.gov
865-241-9138
DOE/Oak Ridge National Laboratory
Source:Eurekalert

Related biology news :

1. Springer to collaborate with the Human Genome Organization
2. Springer launches SpringerImages
3. Battle of the sexes benefits offspring, says research
4. Bisphenol A exposure in pregnant mice permanently changes DNA of offspring
5. Springer Series editor John Smol receives two prestigious biology awards
6. Resilin springs simplify the control of crustacean limb movements
7. Spring agricultural fires have large impact on melting Arctic
8. Mothers give interlopers offspring a head start in life
9. Protein analysis methods, viral vectors featured in Cold Spring Harbor Protocols
10. Just in time for spring: Scientists find the cellular on and off switch for allergies and asthma
11. Springer launches StemCellGateway.net
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/3/2017)... April 3, 2017  Data captured by ... platform, detected a statistically significant association between ... to treatment and objective response of cancer ... to predict whether cancer patients will respond ... as well as to improve both pre-infusion potency ...
(Date:3/29/2017)... CHICAGO , March 29, 2017  higi, the ... ecosystem in North America , today ... Partners and the acquisition of EveryMove. The new investment ... extensive set of tools to transform population health activities ... and lifestyle data. higi collects and secures ...
(Date:3/24/2017)... , Mar 24, 2017 Research and ... Access System Market Analysis & Trends - Industry Forecast to 2025" ... ... to grow at a CAGR of around 15.1% over the next ... This industry report analyzes the market estimates and forecasts for all ...
Breaking Biology News(10 mins):
(Date:10/12/2017)... ... October 12, 2017 , ... DuPont Pioneer and recently ... have entered into a multiyear collaboration to identify and characterize novel CRISPR-Cas nucleases. ... for gene editing across all applications. , Under the terms of the agreement, ...
(Date:10/12/2017)... ... October 12, 2017 , ... ... platform specifically designed for life science researchers to analyze and interpret datasets, ... Franklin, who made a major contribution to the discovery of the double-helix ...
(Date:10/11/2017)... , ... October 11, 2017 , ... ComplianceOnline’s Medical Device ... on 7th and 8th June 2018 in San Francisco, CA. The Summit brings together ... as several distinguished CEOs, board directors and government officials from around the world to ...
(Date:10/11/2017)... ... October 11, 2017 , ... Disappearing forests and increased emissions are the main ... people each year. Especially those living in larger cities are affected by air pollution ... of the most pollution-affected countries globally - decided to take action. , “I knew ...
Breaking Biology Technology: