Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Whale Poop Pumps Up Ocean Health

14.10.2010
Whale feces -- should you be forced to consider such matters -- probably conjure images of, well, whale-scale hunks of crud, heavy lumps that sink to the bottom. But most whales actually deposit waste that floats at the surface of the ocean, "very liquidy, a flocculent plume," says University of Vermont whale biologist, Joe Roman.

And this liquid fecal matter, rich in nutrients, has a huge positive influence on the productivity of ocean fisheries, Roman and his colleague, James McCarthy from Harvard University, have discovered.

Their discovery, published Oct. 11 in the journal PLoS ONE, is what Roman calls a "whale pump."

Whales, they found, carry nutrients such as nitrogen from the depths where they feed back to the surface via their feces. This functions as an upward biological pump, reversing the assumption of some scientists that whales accelerate the loss of nutrients to the bottom.

And this nitrogen input in the Gulf of Maine is "more than the input of all rivers combined," they write, some 23,000 metric tons each year.

It is well known that microbes, plankton, and fish recycle nutrients in ocean waters, but whales and other marine mammals have largely been ignored in this cycle. Yet this study shows that whales historically played a central role in the productivity of ocean ecosystems -- and continue to do so despite diminished populations.

Despite the problems of coastal eutrophication -- like the infamous "dead zones" in the Gulf of Mexico caused by excess nitrogen washing down the Mississippi River -- many places in the ocean of the Northern Hemisphere have a limited nitrogen supply.

Including where Roman and McCarthy completed their study: the once fish-rich Gulf of Maine in the western North Atlantic. There, phytoplankton, the base of the food chain, has a brake on its productivity when nitrogen is used up in the otherwise productive summer months. (In other parts of the ocean, other elements are limiting, like iron in some regions of the Southern oceans.)

"We think whales form a really important direct influence on the production of plants at the base of this food web," says McCarthy.

"We found that whales increase primary productivity," Roman says, allowing more phytoplankton to grow, which then "pushes up the secondary productivity," he says, of the critters that rely on the plankton. The result: "bigger fisheries and higher abundances throughout regions where whales occur in high densities," Roman says.

"In areas where whales were once more numerous than they are today, we suggest that they were more productive," say McCarthy.

The numbers of whales that swam the oceans before human harvests began is a question of some controversy. "Conservative estimates are that large whales have been cut to 25 percent," says Roman, "though the work done on whale genetics shows that we’re probably closer to 10 percent," of historical levels. To cover the range of possibilities, Roman and McCarthy’s study considered several scenarios, estimating current whale stocks as 10, 25, or 50 percent of historical levels.

"Anyway you look at it, whales played a much bigger role in ecosystems in the past than they do now," says Roman, a conservation biologist in the University of Vermont’s Rubenstein School of Environment and Natural Resources and the author of a book on whales.

"And everything that we do to enhance recovery and restoration of the great whales to something like pre-harvest levels works against other deleterious effects that humans are causing in the oceans," says McCarthy, like the decline of overall ocean productivity as climate change drives up water temperatures, which, in turn, causes a decline in nutrients for phytoplankton.

A further implication of the new study is that ongoing calls by some governments to relax international whaling restrictions are ill-considered. Culls and bounty programs would reduce nitrogen and "decrease overall productivity," Roman and McCarthy note.

"For a long time, and still today, Japan and other countries have policies to justify the harvest of marine mammals," says Roman. These countries argue that whales compete with their commercial fisheries.

"Our study flips that idea on its head," Roman says, "Not only is that competition small or non-existent, but actually the whales present can increase nutrients and help fisheries and the health of systems wherever they are found. By restoring populations we have a chance to glimpse how amazingly productive these ecosystems were in the past."

Joshua Brown | Newswise Science News
Further information:
http://www.uvm.edu/~jbrown7

More articles from Ecology, The Environment and Conservation:

nachricht Global threat to primates concerns us all
19.01.2017 | Deutsches Primatenzentrum GmbH - Leibniz-Institut für Primatenforschung

nachricht Reducing household waste with less energy
18.01.2017 | FIZ Karlsruhe – Leibniz-Institut für Informationsinfrastruktur GmbH

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: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | 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

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>