Featured Research

from universities, journals, and other organizations

Small fish can play a big role in coastal carbon cycle

Date:
October 10, 2012
Source:
Virginia Institute of Marine Science
Summary:
Research shows that small forage fish like anchovies can transport carbon into the deep sea through their fecal pellets -- where it contributes nothing to current global warming.

Copepod body parts are visible within the fish fecal pellet: 1, swimming leg; 2, antenna; 3, furcal rami.
Credit: Image courtesy Dr. Grace Saba, Rutgers IMCS

A study in the October 10 issue of Scientific Reports, a new online journal from the Nature Publishing Group, shows that small forage fish like anchovies can play an important role in the "biological pump," the process by which marine life transports carbon dioxide from the atmosphere and surface ocean into the deep sea -- where it contributes nothing to current global warming.

Related Articles


The study, by Dr. Grace Saba of Rutgers University and professor Deborah Steinberg of the Virginia Institute of Marine Science, reports on data collected on an oceanographic expedition to the California coast during Saba's graduate studies at VIMS. Saba, now a post-doctoral researcher in Rutgers' Institute of Marine and Coastal Sciences, earned her Ph.D. from the College of William and Mary's School of Marine Science at VIMS in 2009. The expedition, aboard the research vessel Point Sur, was funded by the National Science Foundation.

The study's focus on fish is a departure for Steinberg and colleagues in her Zooplankton Ecology Lab, who typically study tiny crustaceans called copepods. Research by Steinberg's team during the last two decades has revealed that copepods and other small, drifting marine animals play a key role in the biological pump by grazing on photosynthetic algae near the sea surface, then releasing the carbon they've ingested as "fecal pellets" that can rapidly sink to the deep ocean. The algal cells are themselves generally too small and light to sink.

"'Fecal pellet' is the scientific term for "poop," laughs Steinberg. "Previous studies in our lab and by other researchers show that zooplankton fecal pellets can sink at rates of hundreds to thousands of feet per day, providing an efficient means of moving carbon to depth. But there have been few studies of fecal pellets from fish, thus the impetus for our project."

Saba says, "We collected fecal pellets produced by northern anchovies, a forage fish, in the Santa Barbara Channel off the coast of southern California." She determined that sinking rates for the anchovies' fecal pellets average around 2,500 feet per day, extrapolating from the time required for pellets to descend through a cylinder of water during experiments in the shipboard lab.

At that rate, says Saba, "pellets produced at the surface would travel the 1,600 feet to the seafloor at our study site in less than a day."

Saba and Steinberg also counted the pellets' abundance -- up to 6 per cubic meter of seawater, measured their carbon content -- an average of 22 micrograms per pellet, and painstakingly identified their partly digested contents -- mostly single-celled algae like dinoflagellates and diatoms.

"Twenty micrograms of carbon might not seem like much," says Steinberg, "but when you multiply that by the high numbers of forage fish and fecal pellets that can occur within nutrient-rich coastal zones, the numbers can really add up."

Saba and Steinberg calculate that the total "downward flux" of carbon within fish fecal pellets at their study site reached a maximum of 251 milligrams per square meter per day -- equal to or greater than previously measured values of sinking organic matter collected by suspended "sediment traps."

"Our findings show that -- given the right conditions -- fish fecal pellets can transport significant amounts of repackaged surface material to depth, and do so relatively quickly," says Saba.

Those conditions are likely to occur in places like the western coasts of North and South America, where ocean currents impinge on continental shelves, bringing cold, nutrient-rich waters from depth into the sunlit surface zone.


Story Source:

The above story is based on materials provided by Virginia Institute of Marine Science. Note: Materials may be edited for content and length.


Journal Reference:

  1. Grace K. Saba, Deborah K. Steinberg. Abundance, Composition, and Sinking Rates of Fish Fecal Pellets in the Santa Barbara Channel. Scientific Reports, 2012; 2 DOI: 10.1038/srep00716

Cite This Page:

Virginia Institute of Marine Science. "Small fish can play a big role in coastal carbon cycle." ScienceDaily. ScienceDaily, 10 October 2012. <www.sciencedaily.com/releases/2012/10/121010131532.htm>.
Virginia Institute of Marine Science. (2012, October 10). Small fish can play a big role in coastal carbon cycle. ScienceDaily. Retrieved January 29, 2015 from www.sciencedaily.com/releases/2012/10/121010131532.htm
Virginia Institute of Marine Science. "Small fish can play a big role in coastal carbon cycle." ScienceDaily. www.sciencedaily.com/releases/2012/10/121010131532.htm (accessed January 29, 2015).

Share This


More From ScienceDaily



More Plants & Animals News

Thursday, January 29, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Dogs Bring on So Many Different Emotions in Their Human Best Friends

Dogs Bring on So Many Different Emotions in Their Human Best Friends

RightThisMinute (Jan. 28, 2015) From new-puppy happy tears to helpful-grocery-carrying-dog laughter, our four-legged best friends can make us feel the entire spectrum of emotions. Video provided by RightThisMinute
Powered by NewsLook.com
Scientists Say Earliest Snakes Lived Alongside The Dinosaurs

Scientists Say Earliest Snakes Lived Alongside The Dinosaurs

Newsy (Jan. 28, 2015) Wrongly categorized as lizard fossils, snake fossils now show the reptile could have developed earlier than we thought — 70 million years earlier. Video provided by Newsy
Powered by NewsLook.com
Scientists Hold Emergency Meeting to Save Endangered Rhinos

Scientists Hold Emergency Meeting to Save Endangered Rhinos

AFP (Jan. 28, 2015) Conservationists and scientists hold talks in Kenya to come up with a last ditch plan to save the northern white rhinoceros from extinction. Duration: 01:06 Video provided by AFP
Powered by NewsLook.com
Malnutrition on the Rise as Violence Flares in C. Africa

Malnutrition on the Rise as Violence Flares in C. Africa

AFP (Jan. 28, 2015) Violence can flare up at any moment in Bambari with only a bridge separating Muslims and Christians. Malnutrition is on the rise and lack of water means simple cooking fires threaten to destroy makeshift camps where people are living. Duration: 00:40 Video provided by AFP
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