Featured Research

from universities, journals, and other organizations

Eutrophication Of Lake Constance Led To Genetic Changes In A Species Of Water Flea

Date:
March 18, 2009
Source:
EAWAG: Swiss Federal Institute of Aquatic Science and Technology
Summary:
Ecological changes caused by humans affect natural biodiversity. For example, the eutrophication of Greifensee and Lake Constance in the 1970s and 1980s led to genetic changes in a species of water flea which was ultimately displaced. Despite the fact that water quality has since been significantly improved, this species has not been re-established.

Daphnia Galeata.
Credit: Image courtesy of EAWAG: Swiss Federal Institute of Aquatic Science and Technology

Ecological changes caused by humans affect natural biodiversity. For example, the eutrophication of Greifensee and Lake Constance in the 1970s and 1980s led to genetic changes in a species of water flea which was ultimately displaced.

Related Articles


Despite the fact that water quality has since been significantly improved, this species has not been re-established. This was demonstrated by researchers from Eawag and from two German universities (Frankfurt and Konstanz), who analysed genetic material from Daphnia eggs up to 100 years old.

Evolutionary biologist Nora Brede explains, animatedly: “In the laboratory, we were able to revive resting eggs over 40 years old isolated from Greifensee sediment.” For Eawag, this Jurassic Park-style method has a serious purpose: it makes it possible to determine retrospectively which Daphnia species was dominant in the lake around 1960, and whether the species that prevailed in the 1970s and 1980s became more tolerant of pollutants. Daphnia, which are crustaceans, can produce diapausing (resting) eggs – e.g. when food supplies are inadequate – which develop into a living organism when environmental conditions subsequently become more favourable. As these eggs are deposited in datable layers of anoxic sediments, their DNA can be analysed even after the passage of 100 years or more.

What makes this biological archive particularly interesting is the fact that conditions in the lake have undergone dramatic changes since 1960. In the 1970s and 1980s, inputs of phosphate detergents and fertilizer runoff led to eutrophication, with the development of algal blooms, including toxic cyanobacteria (blue-green algae). Fish died as a result of oxygen depletion.

As reported in the latest edition of the Proceedings of the National Academy of Sciences, the results of the genetic analysis of Daphnia eggs indicate that genetic diversity was also affected by the excessive nutrient levels. At the beginning of the 20th century, only one species of water flea (Daphnia hyalina) occurred abundantly in the two lakes studied. As eutrophication developed, this was displaced by another species (Daphnia galeata). In the transitional periods before and after peak nutrient inputs, hybrids also developed. However, although the lakes are now once again much cleaner (thanks to major efforts in the urban wastewater management sector), the original species has yet to recover.

According to Nora Brede, “This demonstrates that anthropogenic changes, such as eutrophication, can have major and not fully reversible effects on animal species.” In addition, the research project also showed how rapidly evolutionary processes can unfold in the animal kingdom. Brede comments: “In a mere 50 years, there have been measurable changes in the genome structure of a species, which is amazing, given that this is an extremely short period on the timescale of the Earth’s history.”

Biological archives such as the resting eggs of Daphnia in lake sediments are a valuable tool for investigating how organisms respond to changes in the ecosystem. Together with its partners, Eawag is therefore making the most of these opportunities to study and gain a better understanding of evolutionary processes. Research is focusing in particular on the question of how quickly plants and animals adapt genetically to the alterations in temperature associated with global climate change.


Story Source:

The above story is based on materials provided by EAWAG: Swiss Federal Institute of Aquatic Science and Technology. Note: Materials may be edited for content and length.


Journal Reference:

  1. Brede et al. The impact of human-made ecological changes on the genetic architecture of Daphnia species. Proceedings of the National Academy of Sciences, 2009; DOI: 10.1073/pnas.0807187106

Cite This Page:

EAWAG: Swiss Federal Institute of Aquatic Science and Technology. "Eutrophication Of Lake Constance Led To Genetic Changes In A Species Of Water Flea." ScienceDaily. ScienceDaily, 18 March 2009. <www.sciencedaily.com/releases/2009/03/090310134130.htm>.
EAWAG: Swiss Federal Institute of Aquatic Science and Technology. (2009, March 18). Eutrophication Of Lake Constance Led To Genetic Changes In A Species Of Water Flea. ScienceDaily. Retrieved February 27, 2015 from www.sciencedaily.com/releases/2009/03/090310134130.htm
EAWAG: Swiss Federal Institute of Aquatic Science and Technology. "Eutrophication Of Lake Constance Led To Genetic Changes In A Species Of Water Flea." ScienceDaily. www.sciencedaily.com/releases/2009/03/090310134130.htm (accessed February 27, 2015).

Share This


More From ScienceDaily



More Plants & Animals News

Friday, February 27, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Best Drinks for Your Health

The Best Drinks for Your Health

Buzz60 (Feb. 27, 2015) When it comes to health and fitness, there&apos;s lots of talk about what foods to eat, but there are a few liquids that can promote good nutrition. Krystin Goodwin (@krystingoodwin) has the healthiest drinks to boost your health! Video provided by Buzz60
Powered by NewsLook.com
Cherries, Snap Peas and More Tasty Spring Produce

Cherries, Snap Peas and More Tasty Spring Produce

Buzz60 (Feb. 27, 2015) From sweet cherries to sugar snap peas, spring is the peak season for some of the tastiest and healthiest produce. Krystin Goodwin (@Krystingoodwin) has the best seasonal fruits and veggies to spring in to good health! Video provided by Buzz60
Powered by NewsLook.com
The Best Foods to Battle Stress

The Best Foods to Battle Stress

Buzz60 (Feb. 26, 2015) If you&apos;re dealing with anxiety, there are a few foods that can help. Krystin Goodwin (@krystingoodwin) has the best foods to tame stress. Video provided by Buzz60
Powered by NewsLook.com
The Amazon Keeps Its Green Thanks To The Sahara Desert

The Amazon Keeps Its Green Thanks To The Sahara Desert

Newsy (Feb. 25, 2015) Satellite data shows the Amazon rainforest supports its lush flora with a little help from Sahara Desert dust. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins