Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

An enigmatic problem in marine ecology uncovered

10.05.2011
Reef fishes and many other marine species live all their adulthood in one place but early in their lives, when they're eggs and larvae, spend a short period of time drifting and swimming in the open ocean.

It seems intuitive that the duration of this open water period should determine the geographic extent over which species are found as species that spend longer drifting at sea are likely to reach greater distances. Interestingly enough, numerous studies have consistently failed to find any relationship between the duration of the open water period and the geographic coverage of marine species. A new research paper has uncovered this mystery.

"One of the most puzzling results in the study of reef fishes and other marine organisms that dwell sea-floor habitats as adults but drift in open water early in their lives is why their geographic coverage bears no relationship with the duration of the open water period," explains co-author Dr. Camilo Mora, post-doctoral fellow in the Department of Biological Science at Dalhousie University. "Since this idea was first proposed over 30 years ago, we've been scratching our heads trying to resolve this mystery by evaluating the relationship multiple times in different groups of species and regions. Yet we consistently we failed to find a noteworthy relationship."

In this new study, the team of researchers, which included marine ecologists, geneticists and ocean current modelers, first evaluated the possibility that the relationship between geographic extent and the duration of the open water period was compounded by the evolutionary age of species, whose effect has not been considered in previous studies. The rationale was that the age of a species should add to the geographic coverage of species as older species have had more time to expand geographically compared to younger species.

To evaluate this idea, the authors compiled the largest set of data yet assembled on evolutionary ages of reef fish species, and the duration of their open water periods and geographic extents. The analysis of this data showed, however, that even after taking evolutionary age into account there was still no relationship between geographic extent and the duration of the open water period.

"We expected that the effect of species ages could be the missing piece to resolve this puzzle," says co-author Dr. Denis Roy, post-doctoral associate in the Department of Biology/Marine Gene Probe Laboratory at Dalhousie University. "So we were a bit disappointed to find that neither the age of the species nor the duration of the open water period or both combined played an important role on the geographic extent of reef fishes."

"This result, about the limited effect of species ages, deepened our intrigue," says co-author Kate Crosby from Dalhousie University. "The only other thing we could think of was that perhaps reef habitats were so highly connected by ocean currents that species could reach all suitable habitats regardless of their open water period or time since they originated as new species."

To test this idea, the team took on the challenge of modeling the paths of fish larvae during the open water period over the world's tropical reefs. The authors used state of the art models of ocean currents and compiled a worldwide set of data on marine habitats where reef fish dwell. Simulated larvae were released from all possible habitats and allowed to drift for times equal to the duration of their open water periods. The simulation required 600 computer processors running continuously for six months. The results revealed that the majority of reef habitats worldwide are so interconnected that species can quickly spread their geographic distribution pushed by ocean currents. This lack of constraints to the geographic expansion of species provides one of the first explanations for why geographic extent bears no relationship with the duration of the open water period.

"An underlying assumption of the expected relationship between geographic extent and the duration of the open water period is that reef habitats are positioned in a gradient of isolation, which species can bridge only depending on how long the spend drifting in the open ocean," says co-author Dr. Eric Treml, post-doctoral fellow in the School of Biological Sciences at University of Queensland, Australia. "Our simulations of what happens during the open water period suggest that that assumption is just not valid. Given ocean currents, fish larvae can go almost anywhere."

"This is like having a 100 metre race between a car and a bike and giving them one hour to finish; the task is so easy that both vehicles will reach the finish line independent of their speeds," says co-author Jason Roberts at Duke University, U.S.A. "As for reef fishes, ocean currents provide such fast freeways that species can easily reach suitable reefs independent of the time they spend drifting in the open water."

"We've been able to provide new insight into why an intuitively important factor played no role in shaping the geographic extent of reef fish species," says co-author Derek Tittensor at Microsoft Research in Cambridge, U.K. "Given our results, however, a question that still needs to be answered is why all reef fish species are not found everywhere."

Dr. Camilo Mora | EurekAlert!
Further information:
http://www.dal.ca

More articles from Ecology, The Environment and Conservation:

nachricht Joint research project on wastewater for reuse examines pond system in Namibia
19.12.2016 | Technische Universität Darmstadt

nachricht Scientists produce a new roadmap for guiding development & conservation in the Amazon
09.12.2016 | Wildlife Conservation Society

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

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

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

Im Focus: Newly proposed reference datasets improve weather satellite data quality

UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration

"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...

Im Focus: Repairing defects in fiber-reinforced plastics more efficiently

Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.

Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Multiregional brain on a chip

16.01.2017 | Power and Electrical Engineering

New technology enables 5-D imaging in live animals, humans

16.01.2017 | Information Technology

Researchers develop environmentally friendly soy air filter

16.01.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>