Featured Research

from universities, journals, and other organizations

'Red tide' species is deadlier than first thought

Date:
July 23, 2012
Source:
University of Connecticut
Summary:
Researchers have discovered that the plankton species Alexandrium tamarense -- prominent in harmful algal blooms -- contains not one, but two deadly toxins, with potential consequences for marine food chains.

A University of Connecticut researcher and his team have discovered that a species of tiny aquatic organism prominent in harmful algal blooms sometimes called "red tide" is even deadlier than first thought, with potential consequences for entire marine food chains.

Professor Hans Dam and his research group in the school's Department of Marine Sciences have discovered that the plankton species Alexandrium tamarense contains not one but two different types of toxins, one that's deadly to large organisms and one that's deadly to small predators.

"If it's killing multicellular animals with one toxin and small protists with another, it could be the killer of the ocean world," he says.

Dam speculates that this ability to harm both large and small oceanic predators could lead to disruptions in the marine food web during large Alexandrium blooms, like the red tide that occurred along the Northeast coast in 2005, severely affecting the Cape Cod area.

"These small predators that are being affected by the reactive oxygen species are the things that typically eat large amounts of the algae and keep them from growing like crazy," says Dam. "This brings up a whole new line of inquiry for us: What will actually control these algae in the future?"

In small numbers, Alexandrium are virtually harmless to humans, says Dam. But when they're eaten by other clams, mussels or other microorganisms -- which are then eaten by small crustaceans, which are in turn eaten by larger crustaceans or fish -- the toxins can build up in large amounts. So in some parts of the world, eating contaminated shellfish, such as lobsters, clams and fish, has led to illness or death.

However, says Dam, that toxin only affects animals that have central nervous systems.

"This toxin blocks sodium channels in anything that has a well-developed nervous system," he says. "But most of the organisms in the ocean are not those kinds of organisms. They're single-celled, similar to the algae themselves, and they don't have a well-developed nervous system."

Scientists had begun to notice that even though Alexandrium's toxin isn't supposed to affect single-celled animals, when the algae was in the vicinity of some of its one-celled predators, some of those predators got sick and died. Dam's post-doctoral researcher Hayley Flores showed in laboratory experiments that in fact the alga produces a different toxin, called a reactive oxygen species, that kills their predators by popping their cell membrane.

"If you only have one cell, lysing your cell membrane is all it takes to kill you," says Dam. "This new mechanism of toxicity, combined with the other, is pretty evil."

Dam notes that although harmful algal blooms have been linked to human activities, such as pollution runoff from rivers, there are many different factors that could affect the blooms, and scientists still aren't sure exactly how they begin. He speculates that the algae may have become more toxic over time, which has led to their proliferation.

His group will next try to understand how the alga produces the reactive oxygen species and whether it also affects animals multicellular animals. He's also working with researchers at the University of Los Lagos in Chile to understand how Alexandrium may affect important commercial species such as salmon and king crab.

"The amazing thing is, when you look at these algae under a microscope, they're so beautiful -- but they're so deadly," says Dam. "We call them the beautiful assassins."


Story Source:

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


Cite This Page:

University of Connecticut. "'Red tide' species is deadlier than first thought." ScienceDaily. ScienceDaily, 23 July 2012. <www.sciencedaily.com/releases/2012/07/120723134743.htm>.
University of Connecticut. (2012, July 23). 'Red tide' species is deadlier than first thought. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2012/07/120723134743.htm
University of Connecticut. "'Red tide' species is deadlier than first thought." ScienceDaily. www.sciencedaily.com/releases/2012/07/120723134743.htm (accessed July 25, 2014).

Share This




More Plants & Animals News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How to Make Single Serving Smoothies: Howdini Hacks

How to Make Single Serving Smoothies: Howdini Hacks

Howdini (July 24, 2014) Smoothies are a great way to get in lots of healthy ingredients, plus they taste great! Howdini has a trick for making the perfect single-size smoothie that will save you time on cleanup too! All you need is a blender and a mason jar. Video provided by Howdini
Powered by NewsLook.com
Boy Attacked by Shark in Florida

Boy Attacked by Shark in Florida

Reuters - US Online Video (July 24, 2014) An 8-year-old boy is bitten in the leg by a shark while vacationing at a Florida beach. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Goma Cheese Brings Whiff of New Hope to DRC

Goma Cheese Brings Whiff of New Hope to DRC

Reuters - Business Video Online (July 24, 2014) The eastern region of the Democratic Republic of Congo, mainly known for conflict and instability, is an unlikely place for the production of fine cheese. But a farm in the village of Masisi, in North Kivu is slowly transforming perceptions of the area. Known simply as Goma cheese, the Congolese version of Dutch gouda has gained popularity through out the region. Ciara Sutton reports. Video provided by Reuters
Powered by NewsLook.com
Tyrannosaur Pack-Hunting Theory Aided By New Footprints

Tyrannosaur Pack-Hunting Theory Aided By New Footprints

Newsy (July 24, 2014) A new study claims a set of prehistoric T-Rex footprints supports the theory that the giant predators hunted in packs instead of alone. 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