Featured Research

from universities, journals, and other organizations

Changes in water chemistry leave lake critters defenseless

Date:
September 6, 2012
Source:
York University
Summary:
Changes in Canadian lake water chemistry have left small water organisms vulnerable to ambush by predators, according to a new study. Low calcium levels affect the exoskeleton development of water fleas, which are food for fish and keep lakes clean. Plankton in the world's oceans may also be affected.

Daphnia pulex.
Credit: Image courtesy of York University

Imagine that the players on your favourite football team were smaller than their opponents, and had to play without helmets or pads. Left defenseless, they would become easy prey for other teams. Similarly, changes in Canadian lake water chemistry have left small water organisms known as plankton vulnerable to their predators, which may pose a serious environmental threat, according to a new study.

Why do plankton matter? York biology Professor Norman Yan, the study's senior author, says these tiny creatures are critical to our survival. "Without plankton, humans would be quite hungry and perhaps even dead. Much of the world's photosynthesis, the basis of all of our food, comes from the ocean's plankton. The oxygen in every other breath we take is a product of phytoplankton photosynthesis," says Yan.

Yan together with the study's lead author Howard Riessen, a professor of biology at SUNY College at Buffalo, studied the effect of changes in water chemistry on plankton prey defenses. Specifically, they examined how lower calcium concentrations affect Daphnia (water flea) exoskeleton development. These low calcium levels are caused by loss of calcium from forest soils, a consequence of decades of acid rain and multiple cycles of logging and forest growth. The results are published this week in the Proceedings of the National Academy of Sciences.

"At low calcium levels the organisms grow slower and cannot build their armour," says Riessen. "Without suitable armour, they are vulnerable to ambush by predators," he says.

"Calcium is a critical element for Daphnia and many other crustaceans," Riessen says. "Daphnia build their exoskeletons, which include some defensive spines, with calcium to protect themselves from predators. Where calcium levels are low, the Daphnia have softer, smaller, exoskeletons with fewer defensive spines, making them an easy snack."

This phenomenon of reduced calcium is also playing out on a much larger scale in the world's oceans, notes Yan. "Increases in ocean acidity are complicating calcium acquisition by marine life, which is an under-reported effect of global carbon dioxide emissions. Thus marine plankton may also find themselves more vulnerable to predators," he says.

The public is used to stories about changes in water chemistry that lead to large-scale fish kills, says Riessen. "These changes are more insidious. Daphnia might not be a household name, but they are food for fish, and they help keep our lakes clean. Changing the balance between Daphnia and their predators marks a major change in lake systems."


Story Source:

The above story is based on materials provided by York University. Note: Materials may be edited for content and length.


Journal Reference:

  1. H. P. Riessen, R. D. Linley, I. Altshuler, M. Rabus, T. Sollradl, H. Clausen-Schaumann, C. Laforsch, N. D. Yan. Changes in water chemistry can disable plankton prey defenses. Proceedings of the National Academy of Sciences, 2012; DOI: 10.1073/pnas.1209938109

Cite This Page:

York University. "Changes in water chemistry leave lake critters defenseless." ScienceDaily. ScienceDaily, 6 September 2012. <www.sciencedaily.com/releases/2012/09/120906141852.htm>.
York University. (2012, September 6). Changes in water chemistry leave lake critters defenseless. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2012/09/120906141852.htm
York University. "Changes in water chemistry leave lake critters defenseless." ScienceDaily. www.sciencedaily.com/releases/2012/09/120906141852.htm (accessed September 17, 2014).

Share This



More Earth & Climate News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Man Floats for 31 Hours in Gulf Waters

Man Floats for 31 Hours in Gulf Waters

AP (Sep. 16, 2014) A Texas man is lucky to be alive after he and three others floated for more than a day in the Gulf of Mexico when their boat sank during a fishing trip. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Researchers Explore Shipwrecks Off Calif. Coast

Researchers Explore Shipwrecks Off Calif. Coast

AP (Sep. 16, 2014) Federal researchers are exploring more than a dozen underwater sites where they believe ships sank in the treacherous waters west of San Francisco in the decades following the Gold Rush. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Isolated N. Korea Asks For International Help With Volcano

Isolated N. Korea Asks For International Help With Volcano

Newsy (Sep. 16, 2014) Mount Paektu volcano in North Korea is showing signs of life and there's not much known about it. 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:
from the past week

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