A Canada-U.S. research team has found that commercial fisheries play an unexpected role in the decline of water quality in coastal waters. In the latest issue of Nature Geoscience, Roxane Maranger and Nina Caraco explain that the collapse of the fisheries from decades of over fishing has played a significant role in disturbing the balance between nitrogen entering and leaving costal water systems.
The study, the first to examine the world’s 58 coatal regions, shows how failing to maintain ecosystems in a sustainable manner has wide-ranging consequences. Using data provided by the United Nations, Maranger and Caraco found that commercial fishing has played an important, yet declining, role in removing man-made nitrogen from coastal waters.
“Fish accumulate nitrogen as biomass, and when humans move fish from the ocean to the table through commercial fisheries, they are returning part of this terrestrial nitrogen generated by humans back to the land,” said Maranger, a biology professor at the Université de Montréal (Canada).
Caraco, an aquatic biogeochemist at the Cary Institue of Ecosystem Studies (Millbrook, New York, U.S.) notes: ”While nitrogen is essential to plant and animal life in oceans, human export of nitrogen from land to ocean has resulted in exploding nitrogen levels in coastal waters over the past century. Nitrogen-rich fertilizer that’s applied to farmland eventually makes its way into coastal waters via a network of streams and rivers. Fertilizer run-off is a significant source of nitrogen pollution to many coastal regions around the world.”
Four decades ago, commercial fishing removed the equivalent of 60 percent of the nitrogen from coastal oceans that entered as fertilizers. Today, this figure has dropped to 20 percent. “From a historical perspective, this is bad news,” says Maranger. “Increased nitrogen levels in coastal ocean ecosystems throughout the world have resulted in excessive plant growth, lack of oxygen, severe reductions in water quality and in fish and other animal populations.”
In order to manage coastal ecosystems in a sustainable manner, while fully understanding the impact that humans are having on the nitrogen cycle, the scientists recommend the role of commercial fisheries be reexamined.
S-J Desjardins | EurekAlert!
Climate change weakens Walker circulation
20.10.2017 | MARUM - Zentrum für Marine Umweltwissenschaften an der Universität Bremen
Shallow soils promote savannas in South America
20.10.2017 | Senckenberg Forschungsinstitut und Naturmuseen
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Information Technology
20.10.2017 | Materials Sciences
20.10.2017 | Interdisciplinary Research