Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How healthy is that marsh? Biologists count parasites

22.05.2006
Is that salt marsh healthy? To answer this, Sea Grant biologists are cracking open common marsh snails and counting parasitic worms. Their claim: the more parasites, the healthier the marsh.

While the parasite hypothesis may conflict with conventional ideas about infectious disease and human health (malaria, for example, is caused by a parasite), the worms the scientists are investigating are not just any kind of parasite.

For one, these worms, known as trematodes, must sequentially infect certain hosts to complete their lifecycle. Snails to crabs to birds might be a typical sequence for one species, snails to fish to birds for another. These trematodes also stand apart from other parasites in that they cause negligible disease for their highest trophic level hosts, usually birds. The worms’ lifecycle thus typically begins in a snail and ends in a bird, with the intermediate host animals being primary variables among worm species.

Intrigued by the prospects of developing a new tool for monitoring changes in wetland ecology, NOAA’s California Sea Grant recently awarded support to parasite mavens Armand Kuris of the Department of Ecology, Evolution and Marine Biology at the University of California, Santa Barbara, and Kevin Lafferty of the Biological Resources Discipline at the U.S. Geological Survey to collect California horn snails from 30 coastal salt marshes between Marin County and Imperial Beach at the U.S.-Mexico border.

"The horn snail is a mobile data recorder," Lafferty said. "It is a hub for more than 20 trematode species." If any one requisite intermediate host is missing, the parasite cannot reproduce and hence will be underrepresented in the resident snail population, he explained.

A survey of the trematode population in resident snails thus becomes a clever means of reconstructing the food web in the area, as the trematodes reflect the predator-prey relationships that must be occurring to support their reproductive lifecycle.

"Trematodes require all of the pieces of the puzzle to complete their lifecycle," Lafferty said. "When we see a lot of parasites in an estuary, we know it is in good shape. For example, an estuary with high infection rates tells you that it is visited by many birds, and many types of birds."

The goal of the Sea Grant project is to establish a baseline snail-trematode count in marshes, particularly those slated for restoration. By comparing worm statistics before and after a restoration project, which could include activities such as digging channels or removing non-native plants, the biologists believe that wetlands managers will have a tool for gauging restoration success and its gaps.

If, for example, a certain trematode species is missing, it could indicate that its hosts are lacking appropriate habitats. "The trematode information provides a novel way to see what we need to alter to improve habitats," Kuris said.

The feasibility of the snail-as-data-logger idea was established at a case-study site at the Carpinteria salt marsh in Santa Barbara. There, the biologists showed the trematode community did indeed become measurably more vibrant after restoration, due to an increase in the number of birds foraging on infected fish and benthic invertebrates.

To further validate the method, UCSB graduate student Ryan Hechinger conducted four month-long bird surveys at the study site, using video cameras to capture images of as many birds as possible. The results proved encouraging as the video-based estimates of the bird community were in close agreement with those from the snail-trematode analysis. "The more birds there were at a site, the more parasites," Hechinger said. "The more kinds of birds, the more kinds of trematodes, just as we predicted."

Hechinger hopes to produce a manual for resources managers that will explain how to collect snails, identify the trematodes inside them, and then translate this information into information on resident populations of birds, fishes and benthic invertebrates.

"We think counting trematodes is an effective tool for assessing the biodiversity of salt marshes in California," Lafferty said. "We are interested in developing similar techniques for other ecosystems, such as coral reefs and kelp forests."

Wetlands being surveyed as part of the California Sea Grant project:

Wetland, County
Tomales Bay, Marin
Drake’s Estero, Marin
Bolinas Lagoon, Marin
Hayward, Alameda
SE San Fran Bay 92, Alameda
Coyote Hills Slough, Alameda
Newark-Mowry Slough, Alameda
South San Fran Bay, Alameda/Santa Clara
Baylands Region, Santa Clara/San Mateo
Redwood Region, San Mateo
W 92 San Mateo,
Morro Bay, San Luis Obispo
Goleta Slough, Santa Barbara
Carpinteria Salt Marsh, Santa Barbara
Mugu Lagoon, Ventura
Ballona Region, Los Angeles
Cabrillo, Los Angeles
Los Angeles River, Los Angeles
Colorado Lagoon, Los Angeles
Cerritos Wetlands, Los Angeles
Anaheim Bay, Orange
Huntington Beach, Orange
Santa Ana River, Orange
Santa Margarita, San Diego
Agua Hedionda, San Diego
Batiquitos, San Diego
San Elijo, San Diego
San Dieguito, San Diego
Los Peñasquitos, San Diego
Mission Bay, San Diego
San Diego River, San Diego
Famosa Slough, San Diego
San Diego Bay, San Diego
Tijuana Estuary, San Diego

Christina S. Johnson | EurekAlert!
Further information:
http://www.ucsd.edu

More articles from Life Sciences:

nachricht Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?
26.05.2017 | Paul-Ehrlich-Institut - Bundesinstitut für Impfstoffe und biomedizinische Arzneimittel

nachricht Discovery of a Key Regulatory Gene in Cardiac Valve Formation
24.05.2017 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

Physicists discover mechanism behind granular capillary effect

24.05.2017 | Physics and Astronomy

Measured for the first time: Direction of light waves changed by quantum effect

24.05.2017 | Physics and Astronomy

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>