Featured Research

from universities, journals, and other organizations

When the dinner bell rings for seafloor scavengers, larger animals get first dibs

Date:
April 19, 2010
Source:
National Evolutionary Synthesis Center (NESCent)
Summary:
Surplus food can be a double-edged sword for bottom-feeders in the ocean deep, according to a new study. While extra nutrients give a boost to large animals on the deep sea floor, the feeding frenzy that results wreaks havoc on smaller animals in the seafloor sediment, researchers say.

Small marine animals called macrofauna -- snails, worms, clams, and other creatures no bigger than a pencil eraser -- live and feed in the seafloor sediment.
Credit: Craig McClain

Surplus food can be a double-edged sword for bottom-feeders in the ocean deep, according to a new study in the April issue of Ecology. While extra nutrients give a boost to large animals on the deep sea floor, the feeding frenzy that results wreaks havoc on smaller animals in the seafloor sediment, researchers say.

Related Articles


Descend thousands of feet under the ocean to the deep sea floor, and you'll find a blue-black world of cold and darkness, blanketed in muddy ooze. In this world without sunlight, food is often in short supply.

Animals in the deep sea survive on dead and decaying matter drifting down from above, said marine biologist Craig McClain of the National Evolutionary Synthesis Center. Only about 3-5% of the remains of microscopic plants and animals that feed life at shallower depths actually makes it to the deep sea floor, he explained. "If the ocean's primary production were a 5-pound bag of sugar, that would be the equivalent of a sugar packet."

Collaborating with James Barry of the Monterey Bay Aquarium Research Institute (MBARI), McClain traveled to the deep waters off the coast of California to an area of the ocean floor that receives an additional source of food. In a steep, winding, underwater gorge known as Monterey Canyon -- similar in size to the Grand Canyon -- bottom-feeders get a boost from nutrient-rich sediments that slough off the canyon walls and collect on the canyon floor.

"There's typically more food available in the canyon than you would see outside the canyon," Barry explained. "The stuff that rains down from above and accumulates at the base of the cliffs isn't just mud -- it's food," McClain added. "There are tiny food particles and bacteria in the sediment."

The researchers wanted to understand how the surplus food affected deep sea life on the canyon floor. Buried in the sediment and hidden from view, a diverse world of tiny marine animals -- snails, worms, crustaceans, clams, and other creatures no bigger than a pencil eraser -- live and feed in the canyon mud.

To find out how these animals are affected by the boost of food, the researchers sent a Remotely Operated Vehicle (ROV) equipped with video and sampling equipment to the base of the canyon. Piloted from a control room onboard a ship at the ocean surface, the ROV dove more than a mile to the canyon floor. As the ROV crept across the seafloor sediment, it video recorded everything in its path and pushed plastic tubes into the mud, pulling up cores of and animals and silt.

When they brought the samples back to the surface, they found nearly 200 species in the sediment. But as they sampled closer to the canyon walls, they were surprised to find that despite the extra food and nutrients, the small sediment-dwellers (0.25 to 25 mm in size) became even smaller and less diverse. Why might this be?

A closer look at the video footage suggests the answer lies not in the sediment, but just above. As the ROV approached the canyon walls, the researchers noticed swarms of bigger, mobile animals -- crabs, starfish, urchins, sea cucumbers and other seafloor scavengers -- crawling on the sediment surface. Normally few and far between, these animals sense that food has arrived and converge at the base of the cliffs, the researchers explained. "The cliff face becomes a smorgasbord for larger animals," said McClain.

Ironically, more food for big, mobile animals on the sediment surface is bad news for smaller sediment-dwellers buried below. The larger animals devour all the food in their path as they plow across the canyon floor, wrecking habitat and leaving little for other animals to feed on. "Larger organisms come in and they churn up the sediment and eat all the food. That has big consequences for smaller animals that live there," McClain explained.

"The number of species near the cliff face was reduced by half compared to the middle of the canyon," said McClain. "More food isn't always better," he added.

The team's findings will be published online in the April 2010 issue of Ecology.


Story Source:

The above story is based on materials provided by National Evolutionary Synthesis Center (NESCent). Note: Materials may be edited for content and length.


Journal Reference:

  1. McClain, C. and J. P. Barry. Habitat heterogeneity, biogenic disturbance, and resource availability work in concert to regulate biodiversity in deep submarine canyons. Ecology, April 2010

Cite This Page:

National Evolutionary Synthesis Center (NESCent). "When the dinner bell rings for seafloor scavengers, larger animals get first dibs." ScienceDaily. ScienceDaily, 19 April 2010. <www.sciencedaily.com/releases/2010/04/100405111210.htm>.
National Evolutionary Synthesis Center (NESCent). (2010, April 19). When the dinner bell rings for seafloor scavengers, larger animals get first dibs. ScienceDaily. Retrieved November 28, 2014 from www.sciencedaily.com/releases/2010/04/100405111210.htm
National Evolutionary Synthesis Center (NESCent). "When the dinner bell rings for seafloor scavengers, larger animals get first dibs." ScienceDaily. www.sciencedaily.com/releases/2010/04/100405111210.htm (accessed November 28, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Friday, November 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Research on Bats Could Help Develop Drugs Against Ebola

Research on Bats Could Help Develop Drugs Against Ebola

AFP (Nov. 28, 2014) In Africa's only biosafety level 4 laboratory, scientists have been carrying out experiments on bats to understand how virus like Ebola are being transmitted, and how some of them resist to it. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
New Dinosaur Species Found in Museum Collection

New Dinosaur Species Found in Museum Collection

Reuters - Innovations Video Online (Nov. 27, 2014) A British palaeontologist has discovered a new species of dinosaur while studying fossils in a Canadian museum. Pentaceratops aquilonius was related to Triceratops and lived at the end of the Cretaceous Period, around 75 million years ago. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Tryptophan Isn't Making You Sleepy On Thanksgiving

Tryptophan Isn't Making You Sleepy On Thanksgiving

Newsy (Nov. 27, 2014) Tryptophan, a chemical found naturally in turkey meat, gets blamed for sleepiness after Thanksgiving meals. But science points to other culprits. Video provided by Newsy
Powered by NewsLook.com
Classic Hollywood Memorabilia Goes Under the Hammer

Classic Hollywood Memorabilia Goes Under the Hammer

Reuters - Entertainment Video Online (Nov. 26, 2014) The iconic piano from "Casablanca" and the Cowardly Lion suit from "The Wizard of Oz" fetch millions at auction. Sara Hemrajani reports. Video provided by Reuters
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