Navigation Links
Greenhouse ocean may downsize fish
Date:1/11/2008

The last fish you ate probably came from the Bering Sea.

But during this century, the seas rich food webstretching from Alaska to Russiacould fray as algae adapt to greenhouse conditions.

All the fish that ends up in McDonalds, fish sandwichesthats all Bering Sea fish, said USC marine ecologist Dave Hutchins, whose former student at the University of Delaware, Clinton Hare, led research published Dec. 20 in Marine Ecology Progress Series, a leading journal in the field.

At present, the Bering Sea provides roughly half the fish caught in U.S. waters each year and nearly a third caught worldwide.

The experiments we did up there definitely suggest that the changing ecosystem may support less of what were harvestingthings like pollock and hake, Hutchins said.

While the study must be interpreted cautiously, its implications are harrowing, Hutchins said, especially since the Bering Sea is already warming.

It's kind of a canary in a coal mine because it appears to be showing climate change effects before the rest of the ocean, he noted.

Its warmer, marine mammals and birds are having massive die-offs, there are invasive speciesin general, its changing to a more temperate ecosystem thats not going to be as productive.

Carbon dioxides direct effects on the ocean are often overlooked by the public.

Its all a good start that people get worried about melting ice and rising sea levels, he said. But we're now driving a comprehensive change in the way Earth's ecosystem worksand some of these changes don't bode well for its future.

The study examined how climate change affects algal communities of phytoplankton, the heart of marine food webs.

Phytoplankton use sunlight to convert carbon dioxide into carbon-based food. As small fish eat the plankton and bigger fish eat the smaller fish, an entire ecosystem develops.

The Bering Sea is highly productive thanks mainly to diatoms, a large type of phytoplankton.

Because they're large, diatoms are eaten by large zooplankton, which are then eaten by large fish, Hutchins explained.

The scientists found that greenhouse conditions favored smaller types of phytoplankton over diatoms. Such a shift would ripple up the food chain: as diatoms become scarce, animals that eat diatoms would become scarce, and so forth.

The food chain seems to be changing in a way that is not supporting these top predators, of which, of course, were the biggest, Hutchins said.

A shift away from diatoms towards smaller phytoplankton could also undermine a key climate regulator called the biological pump.

When diatoms die, their heavier carbon-based remains sink to the seafloor. This creates a pump whereby diatoms transport carbon from the atmosphere into deep-sea storage, where it remains for at least 1,000 years.

While smaller species often fix more carbon, they end up re-releasing CO2 in the surface ocean rather than storing it for long periods as the diatom-based community can do, Hutchins explained.

This scenario could make the ocean less able to soak up atmospheric carbon dioxide.

Right now, the ocean biology is sort of on our side, Hutchins said. About 50 percent of fossil fuel emissions since the industrial revolution is in the ocean, so if we didnt have the ocean, atmospheric CO2 would be roughly twice what it is now.

Hutchins and colleagues are doing related experiments in the north Atlantic Ocean and the Ross Sea, near Antarctica. The basic dynamics of a greenhouse ocean are not well understood, he noted.

Were trying to make a contribution by doing predictive experimental research that will help us understand where were headed, he said. Its unprecedented the rate at which things are shifting around.

The researchers collected the algae samples from the Bering Seas central basin and the southeastern continental shelf. They incubated the phytoplankton onboard, simulating sea surface temperatures and carbon dioxide concentrations predicted for 2100.

Each of these variables was tested together and independently. Ratios of diatom to nanophytoplankton in manipulated samples were then compared with those in plankton grown under present conditions.

The scientists found that photosynthesis in greenhouse samples sped up two to three times current rates. However, community composition shifted from diatoms to the smaller nanophytoplankton.

Temperature was the key driver of the shift with secondary impacts from the increased carbon dioxide concentrations, according to the study.


'/>"/>

Contact: Terah DeJong
tdejong@usc.edu
213-740-8606
University of Southern California
Source:Eurekalert

Related biology news :

1. UC San Diego begins trading greenhouse gas credits on Chicago Climate Exchange
2. A link between greenhouse gases and the evolution of C4 grasses
3. Greenhouse gas from English streams
4. Hellish hot springs yield greenhouse gas-eating bug
5. Biodiesel could reduce greenhouse gas emissions
6. Planting carbon deep in the earth -- rather than the greenhouse
7. Economical, nonpolluting solutions to greenhouse growing found
8. RIT to study air pollution and greenhouse gas emissions in the Great Lakes region
9. A greenhouse in order to study the impact of climate change on plants
10. Deep-sea species loss could lead to oceans collapse, study suggests
11. Scientists find good news about methane bubbling up from the ocean floor
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/22/2016)... American College of Medical Genetics and Genomics was once again ... of the fastest-growing trade shows during the Fastest 50 Awards ... Las Vegas . Winners are ... of the following categories: net square feet of paid exhibit ... 2015 ACMG Annual Meeting was ranked 23 out of 50 ...
(Date:6/20/2016)... -- Securus Technologies, a leading provider of civil ... investigation, corrections and monitoring announced that after exhaustive ... the final acceptance by all three (3) Department ... (MAS) installed. Furthermore, Securus will have contracts for ... October, 2016. MAS distinguishes between legitimate wireless device ...
(Date:6/9/2016)... 2016 Paris Police Prefecture ... security solution to ensure the safety of people and operations ... the major tournament Teleste, an international technology group ... announced today that its video security solution will be utilised ... up public safety across the country. The system roll-out is ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... (PRWEB) , ... June 23, 2016 , ... ... the release of its second eBook, “Clinical Trials Patient Recruitment and Retention Tips.” ... and retention in this eBook by providing practical tips, tools, and strategies for ...
(Date:6/23/2016)... Houston Methodist Willowbrook Hospital has signed ... to serve as their official health care provider. ... will provide sponsorship support, athletic training services, and ... volunteers, athletes and families. "We are ... and to bring Houston Methodist quality services and ...
(Date:6/23/2016)... ... 23, 2016 , ... Supplyframe, the Industry Network for electronics ... Lab . Located in Pasadena, Calif., the Design Lab’s mission is to bring ... designed, built and brought to market. , The Design Lab is Supplyframe’s physical ...
(Date:6/23/2016)... , June 23, 2016 ... Hematology Review, 2016;12(1):22-8 http://doi.org/10.17925/OHR.2016.12.01.22 ... , the peer-reviewed journal from touchONCOLOGY, Andrew ... escalating cost of cancer care is placing an ... result of expensive biologic therapies. With the patents ...
Breaking Biology Technology: