Navigation Links
Ocean seep mollusks may share evolutionary history with other deep-sea creatures

The unusual mollusks of oceanic cold seeps--strange clams, mussels and sea snails that thrive in the sulfur and methane-rich environments--are on average older than the marine mollusk community as a whole, according to a new report in the 8 September issue of the journal Science, published by AAAS, the nonprofit science society.

On average, the first appearance of cold seep mollusk genera in the geological record is a full epoch earlier than that of marine mollusks in general, according to Steffen Kiel and Crispin Little of the University of Leeds.

These findings indicate that the long evolutionary history of the seep mollusks is more similar to that of other deep-sea animals than to some of their mollusk contemporaries from other parts of the oceans.

Cold seeps may have been--and continue to be--safe harbors for the mollusks, protecting them from mass extinctions and possible abrupt oxygen changes in the seas, the researchers found. However, many deep-sea species outside of the cold seeps have also managed to ride out these changes.

"The shallow water environment is much more challenging, subject to changes in sea levels, extinction events, pollution, sediment runoff--all sorts of factors which don't affect animals in the deep sea," Little explained.

This makes it difficult to tell whether seep mollusks owe their long evolutionary history to their unique home environment or to their status as deep-sea creatures, he noted.

Cold seeps are places where fluids rich in hydrogen sulfide and methane leak up through the ocean floor, creating a unique chemical environment where hardy bacteria process the sulfide and methane. Seep fluids are about the same temperature as surrounding waters, but similar chemically challenging environments exist at hydrothermal vents, fissures in the ocean floor where water is superheated by magma lurking just below the crust.

Although seep and vent fluids are a poisonous brew for most sp ecies, animals such as giant tube worms and the mollusks studied by Kiel and Little thrive with the help of the symbiotic bacteria. "If you can become adapted to living at these sites, you can make a very good living indeed," Little said.

The origins and age of seep citizens such as the mollusks has been debated for some time by scientists using both fossil and genetic evidence. Kiel and Little decided to examine the fossil record for modern seep mollusks to see how their history compared to that of the overall marine mollusk population.

By sorting 29 mollusk genera into the geological time periods when they first appeared, the researchers found that seep mollusk genera, on average, appeared during the Eocene epoch about 55 to 34 million years ago. By contrast, the average age of first appearances for all marine mollusks occurred in the Oligocene epoch, about 34 to 24 million years ago.

Following the fortunes of seep mollusks through time, Kiel and Little also found little evidence that mass extinction events or periods of low oxygen dealt significant blows to the seep communities. Seeps may have been good shelters during these events because "they were driven by a constant source of geothermal energy," Little said.

The Eocene age calculated by the Science researchers casts some doubt on another mystery involving seep animals: what is their relationship to whale falls? Whale falls, the slowly decaying remains of large whales sunk to the ocean's depths, harbor yet another unique chemical community similar to that in vents and seeps.

Some researchers suggest that whale falls were evolutionary "stepping stones," creating new environments for seep animals to evolve into a plethora of new species. But Kiel and Little's work shows that more than three-quarters of seep mollusk genera had already appeared by the time oceangoing whales would have filled the seas.

Whale falls "are not instrumental in the evolution" of seep mol lusks, but the falls "may have allowed them to expand into new sites," Little explained.

"Cold seep mollusks are older than the general marine mollusk fauna" by Steffen Kiel and Crispin T.S. Littleat the University of Leeds.


'"/>

Source:American Association for the Advancement of Science


Related biology news :

1. Oceans more vulnerable to agricultural runoff than previously thought, study finds
2. Breakthrough System for Understanding Ocean Plant Life Announced
3. Ocean climate predicts elk population in Canadian Rockies
4. New Scripps Oceanography project to study sediments and ecosystem restoration in Venice lagoon
5. Oceans turning to acid from rise in CO2
6. The Antarctic Ocean floor
7. Ocean dead zones trigger sex changes in fish, posing extinction threat
8. Oceans are 70 percent shark free
9. Ocean virus identified in human blood samples
10. MIT: Oceans are a major gene swap-meet for plankton
11. Ocean acidification threatens cold-water coral ecosystems
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:6/21/2016)... 21, 2016 NuData Security announced today that ... of principal product architect and that Jon ... customer development. Both will report directly to ... moves reflect NuData,s strategic growth in its product ... customer demand and customer focus values. ...
(Date:6/15/2016)... York , June 15, 2016 ... new market report titled "Gesture Recognition Market by Application ... Forecast, 2016 - 2024". According to the report, the  ... 11.60 billion in 2015 and is estimated to ... USD 48.56 billion by 2024.  Increasing ...
(Date:6/7/2016)... , June 7, 2016  Syngrafii Inc. and ... business relationship that includes integrating Syngrafii,s patented LongPen™ ... project. This collaboration will result in greater convenience ... credit union, while maintaining existing document workflow and ... ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... 23, 2016  The Biodesign Challenge (BDC), a university ... to harness living systems and biotechnology, announced its winning ... New York City . ... showcased projects at MoMA,s Celeste Bartos Theater during the ... MoMA,s senior curator of architecture and design, and ...
(Date:6/23/2016)... ... June 23, 2016 , ... STACS DNA Inc., the sample tracking software company, ... Crime Laboratory, has joined STACS DNA as a Field Application Specialist. , “I ... President and COO of STACS DNA. “In further expanding our capacity as a scientific ...
(Date:6/23/2016)... , June 23, 2016  Blueprint Bio, a company ... to the medical community, has closed its Series A ... Nunez . "We have received a commitment ... capital we need to meet our current goals," stated ... us the runway to complete validation on the current ...
(Date:6/23/2016)... ... June 23, 2016 , ... ClinCapture, the only free ... and will showcase its product’s latest features from June 26 to June 30, ... poster on Disrupting Clinical Trials in The Cloud during the conference. DIA ...
Breaking Biology Technology: