Featured Research

from universities, journals, and other organizations

Parasites Vastly Outweigh Predators In Estuaries: Could Have Significant Ecological Implications

Date:
July 24, 2008
Source:
University of California - Santa Barbara
Summary:
In a study of free-living and parasitic species in three estuaries on the Pacific coast of California and Baja California, researchers have determined that parasite biomass in those habitats exceeds that of top predators, in some cases by a factor of 20. Their findings, which could have significant biomedical and ecological implications, appear in the science journal Nature. From an ecological perspective, parasites serve both as regulators to prevent species from becoming numerically dominant and as indicators of the health of a particular ecosystem. The study shows for the first time that parasites might drive the flow of energy in ecosystems.

Bahia San Quintín (Baja California, Mexico)
Credit: Kevin Lafferty

In a study of free-living and parasitic species in three estuaries on the Pacific coast of California and Baja California, a team of researchers from the University of California, Santa Barbara, the United States Geological Survey, and Princeton University has determined that parasite biomass in those habitats exceeds that of top predators, in some cases by a factor of 20.

Their findings, which could have significant biomedical and ecological implications, appear in the July 24 issue of the science journal Nature.

According to Armand Kuris, a professor of zoology in UCSB's Department of Ecology, Evolution, and Marine Biology and a lead author of the paper, the study's findings have a potential impact on the perceived role of parasites in an ecosystem. From an ecological perspective, parasites serve both as regulators to prevent species from becoming numerically dominant and as indicators of the health of a particular ecosystem. The study shows for the first time that parasites might drive the flow of energy in ecosystems.

"The total amount of energy flow in ecosystems due to infectious processes must be enormous - even greater than we'd expect given the large parasite biomass," Kuris said. "I expect the amount of energy going into host tissue repair and replenishment is also huge. An implication of our study is that we should pay more attention to the energetics of disease."

Biomass is the amount of living matter that exists in a given habitat. It is expressed either as the weight of organisms per unit area or as the volume of organisms per unit volume of habitat. Until now, scientists have believed that because parasites are microscopic in size they comprise a small fraction of biomass in a habitat while free-living organisms such as fish, birds, and other predators comprise the vast majority.

The researchers quantified the biomass of free-living and parasitic species in the three estuaries and demonstrated that parasites have substantial biomass in these ecosystems. "Parasites have as much, or even more, biomass than other important groups of animals - like birds, fishes, and crabs," said Ryan Hechinger, a researcher at UCSB's Marine Science Institute and co-lead author of the paper.

The article grew out of a five-year study supported by a $2.2 million grant from the National Science Foundation and the National Institutes of Health through the agencies' joint Ecology of Infectious Diseases Program. In addition to Kuris, principal investigators include Kevin Lafferty, a marine ecologist with the United States Geological Survey; and Andrew Dobson, a professor of ecology and evolutionary biology at Princeton University. Other important collaborators included Leopoldina Aguirre-Macedo, of the Centro de Investigación y Estudios Avanzados Unidad Mérida, and Mark Torchin, a staff scientist with the Smithsonian Tropical Research Institute.

The researchers quantified parasites and free-living organisms in the Carpinteria Salt Marsh and in the Bahia San Quintín and Estero de Punta Banda estuaries in Baja California. Their study included 199 species of free-living animals, 15 species of free-living vascular plants, and 138 species of parasites.

"The reason we wanted to complete this study is because a lot of work we've done has suggested that parasites are important in ecosystems. But no one's actually looked at them as a group throughout an ecosystem," said Lafferty. "Also, no one's considered parasites from the perspective of how much they weigh because it's always been assumed they weigh almost nothing. Now we know that's not true.

"For example, in an estuary there are more kilograms of trematode worms - parasites - than kilograms of birds," he noted. "If you could see the trematodes with binoculars, you might not bother bird watching."

Said Hechinger: "No one debates whether it's important for ensuring human welfare to understand how ecosystems work. How can we possibly understand something without accounting for its major parts? Because our findings indicate that parasites control a massive amount of biomass, it would seem future research can't ignore them."

According to Kuris, understanding the enormity of parasite biomass and the burden it places on available hosts could lead to new strategies in the management of infectious diseases. Treatment protocols might put greater emphasis on enhancing the host's ability to defend itself against parasitic disease and slow the rate of energy uptake by the parasites and pathogens.


Story Source:

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


Cite This Page:

University of California - Santa Barbara. "Parasites Vastly Outweigh Predators In Estuaries: Could Have Significant Ecological Implications." ScienceDaily. ScienceDaily, 24 July 2008. <www.sciencedaily.com/releases/2008/07/080723140323.htm>.
University of California - Santa Barbara. (2008, July 24). Parasites Vastly Outweigh Predators In Estuaries: Could Have Significant Ecological Implications. ScienceDaily. Retrieved September 20, 2014 from www.sciencedaily.com/releases/2008/07/080723140323.htm
University of California - Santa Barbara. "Parasites Vastly Outweigh Predators In Estuaries: Could Have Significant Ecological Implications." ScienceDaily. www.sciencedaily.com/releases/2008/07/080723140323.htm (accessed September 20, 2014).

Share This



More Plants & Animals News

Saturday, September 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Chocolate Museum Opens in Brussels

Chocolate Museum Opens in Brussels

AFP (Sep. 19, 2014) — Considered a "national heritage" in Belgium, chocolate now has a new museum in Brussels. In a former chocolate factory, visitors to the permanent exhibition spaces, workshops and tastings can discover derivatives of the cocoa bean. Duration: 01:00 Video provided by AFP
Powered by NewsLook.com
Could Grief Affect The Immune Systems Of Senior Citizens?

Could Grief Affect The Immune Systems Of Senior Citizens?

Newsy (Sep. 19, 2014) — The study found elderly people are much more likely to become susceptible to infection than younger adults going though a similar situation. Video provided by Newsy
Powered by NewsLook.com
Jury Delivers Verdict in Salmonella Trial

Jury Delivers Verdict in Salmonella Trial

AP (Sep. 19, 2014) — A federal jury has convicted three people in connection with an outbreak of salmonella poisoning five years ago that sickened hundreds of people and was linked to a number of deaths. (Sept. 19) Video provided by AP
Powered by NewsLook.com
Raw: Elephant Undergoes Surgery in Tbilisi Zoo

Raw: Elephant Undergoes Surgery in Tbilisi Zoo

AP (Sep. 18, 2014) — Grand the elephant has successfully undergone surgery to remove a portion of infected tusk at Tbilisi Zoo in Georgia. British veterinary surgeons used an electric drill to extract the infected piece. (Sept. 18) Video provided by AP
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