Navigation Links
Sunken logs create new worlds for seafloor animals
Date:4/9/2014

MOSS LANDING, CA When it comes to food, most of the deep sea is a desert. Many seafloor animals feed on marine snowthe organic remnants of algae and animals that live in the sunlit surface waters, far above. However, marine snow only falls as a light dusting and doesn't have much nutritional value. Thus, any other sources of food that reach the deep sea provide a temporary feast. Even bits of dead wood, waterlogged enough to sink, can support thriving communities of specialized animals. A new paper by biologists at the National Evolutionary Synthesis Center and the Monterey Bay Aquarium Research Institute (MBARI) shows that wood-boring clams serve as "ecosystem engineers," making the organic matter in the wood available to other animals that colonize wood falls in the deep waters of Monterey Canyon.

In 2006, marine biologists Craig McClain and Jim Barry used MBARI's remotely operated vehicle Tiburon to place 36 bundles of acacia wood on the canyon floor, 3,200 meters below the sea surface. Five years later, they retrieved the bundles and McClain painstakingly picked out every animal that had colonized the logs.

McClain performed a variety of statistical analyses on the different types of animals found in each of the bundles, looking for differences and similarities. The results were surprising. Even though all of the bundles contained exactly the same type of wood and were placed on the seafloor at the same time, within a few tens of meters of each other, there were huge differences in the numbers and types of animals from one bundle to another.

Some of the bundles had been heavily colonized. The seafloor around and under these bundles was carpeted with tiny wood chips and fecal pellets from wood-boring clams, as well as bacteria and fungi that help decompose this organic matter. Other wood bundles had few, if any animals living in them, and lacked these "halos" of discolored sediment.

McClain's statistical analysis showed that as the wood got older and more heavily colonized by wood-boring clams (Xylophaga zierenbergi), the types and abundances of other animals also changed. Boring clams are one of the few marine animals that can digest the cellulose in wood. Like termites, these clams have specialized symbiotic bacteria in their bodies that help them digest cellulose. As McClain put it, "Without these wood-boring bivalves, the carbon energy in the wood would not be available to other species." McClain calls these clams "ecosystem engineers." He explains, "Like oysters, beavers, and termites, these boring clams alter the landscape and provide new habitat for other species."

As they eat their way through a sunken log, boring clams create lots of small holes in which other animals can hide. Their wood chips and feces provide food for a variety of smaller animals. And the clams themselves provide food for specialized predators. The details of these interactions are still poorly known. For example, after boring clams, the most common animals McCain found in his bundles were tiny, shrimp-like crustaceans known as tanaids. The authors speculate that these tanaids may prey directly on the boring clams. Alternatively, the tanaids may consume the fecal pellets of boring clams and the bacteria associated with them (any organic matter is precious when you're three kilometers below the ocean surface).

The statistical analyses also showed that large logs supported more diverse communities of animals than small logs. The researchers speculated that larger logs may provide food for a longer time period, which attracts more secondary colonizers, such as deep-sea snails. McClain explained, "Snails, contrary to what you might expect, are metabolically expensive. They may need a lot of energy, such as that found a large wood fall, to support a viable population."

One of the most surprising discoveries was that, even after five years, some bundles contained only a few small, young boring clams, and other bundles contained no clams at all. The researchers could find no obvious reasons why the clams would colonize some bundles but not others.

McClain said, "The part that really excites and puzzles me is that not all the wood falls were colonized at the same time. At the end of the experiment some wood was not bored or bored very little. This didn't reflect the placement, size, cut, or surface area of the logs. Basically it appears that the recruitment of larval clams into the wood fall was a nearly random process, even for logs that were just a few meters from one another."

The rate at which a wood fall is colonized makes a big difference to deep-sea organisms living nearby. The faster that a piece of wood is colonized, the more rapidly its organic matter is made available to non-wood-eating animals. Thus, hard woods or woods containing clam-repellent compounds, might last much longer than soft woods, and might provide less food for animals on the nearby seafloor.

Whatever the reason, these differences in colonization from one wood fall to another created a wide variety of habitats and animal communities over a relatively small patch of seafloor. Thus, this study adds to the growing body of evidence that, although the deep seafloor may look flat and uniform, its animal communities often vary considerably over both space and time.


'/>"/>

Contact: Kim Fulton-Bennett
kfb@mbari.org
831-775-1835
Monterey Bay Aquarium Research Institute
Source:Eurekalert  

Related biology news :

1. Self-assembled superlattices create molecular machines with hinges and gears
2. UCSB researchers create first regional Ocean Health Index
3. A*STAR scientists create stem cells from a drop of blood
4. New process uses recyclable catalyst to create porous materials
5. Wasps use ancient aggression genes to create social groups
6. UT Arlington bioengineer to create new nanoparticle system to shore up arterial walls
7. Study shows autistic brains create more information at rest
8. Price Family Foundation gift will create groundbreaking structural biology institute
9. Humans in nature: The world as we find it and the world as we create it
10. How does the brain create sequences?
11. American Chemical Society podcast: Small dams create greenhouse gas hot spots
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Sunken logs create new worlds for seafloor animals
(Date:4/11/2017)... , April 11, 2017 NXT-ID, ... security technology company, announces the appointment of independent Directors Mr. ... to its Board of Directors, furthering the company,s corporate ... ... NXT-ID, we look forward to their guidance and benefiting from ...
(Date:4/5/2017)... April 5, 2017 Today HYPR Corp. ... the server component of the HYPR platform is officially ... the end-to-end security architecture that empowers biometric authentication across ... has already secured over 15 million users across the ... of connected home product suites and physical access represent ...
(Date:4/3/2017)... 2017  Data captured by IsoCode, IsoPlexis ... a statistically significant association between the potency ... and objective response of cancer patients post-treatment. ... whether cancer patients will respond to CAR-T ... as to improve both pre-infusion potency testing and ...
Breaking Biology News(10 mins):
(Date:10/11/2017)... ... October 11, 2017 , ... ... Andi Purple announced Dr. Suneel I. Sheikh, the co-founder, CEO and chief research ... Inc. has been selected for membership in ARCS Alumni Hall of Fame ...
(Date:10/11/2017)... CA, USA (PRWEB) , ... October 11, 2017 , ... ... to take place on 7th and 8th June 2018 in San Francisco, CA. The ... influencers as well as several distinguished CEOs, board directors and government officials from around ...
(Date:10/11/2017)... and LAGUNA HILLS, Calif. , Oct. 11, ... Research, London (ICR) and University of ... SkylineDx,s prognostic tool to risk-stratify patients with multiple myeloma (MM), ... nine . The University of Leeds ... funded by Myeloma UK, and ICR will perform the testing ...
(Date:10/11/2017)... (PRWEB) , ... October 11, 2017 , ... ... Administration (FDA) has granted orphan drug designation to SBT-100, its novel anti-STAT3 (Signal ... the treatment of osteosarcoma. SBT-100 is able to cross the cell membrane and ...
Breaking Biology Technology: