 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
| . |  |
. |
 by Staff Writers Sendai, Japan (SPX) Feb 03, 2020
Water layering is intensifying significantly in about 40% of the world's oceans, which could have an impact on the marine food chain. The finding, published in the Journal of Geophysical Research: Oceans, could be linked to global warming. Tohoku University geophysicist Toshio Suga collaborated with climate physicist Ryohei Yamaguchi of Korea's Pusan National University to investigate how upper-ocean stratification has changed over a period of 60 years. Upper-ocean stratification is the presence of water layers of varying densities scattered between the ocean's surface and a depth of 200 metres. Density describes how tightly water is packed within a given volume and is affected by water temperature, salinity and depth. More dense water layers lie beneath less dense ones. Ocean water density plays a vital role in ocean currents, heat circulation, and in bringing vital nutrients to the surface from deeper waters. The more significant the stratification in the upper ocean, the larger the barrier between the relatively warm, nutrient-depleted surface, and the relatively cool, nutrient-rich, deeper waters. More intense stratification could mean that microscopic photosynthetic organisms called phytoplankton that live near the ocean's surface won't get the nutrients they need to survive, affecting the rest of the marine food chain. Scientists think that global warming could be increasing upper ocean stratification, but investigations have been limited and have usually used short-term data, leading to a large degree of uncertainty. Suga and Yamaguchi compiled temperature and salinity data from the World Ocean Database 2013, covering the period from 1960 to 2017. They then used mathematical equations to calculate the difference in temperature and salinity content between 10 and 200 metres in the regions where data was available. They found that around 40% of the world's oceans are witnessing a rise in upper ocean density stratification. Half of this rise is happening in tropical waters. They also found that rising stratification in mid-latitude and high-latitude oceans of the Northern Hemisphere varied seasonally, with faster changes happening in the summer compared to winter months. Additionally, inter-annual variations in several regions correlated with climatic events, such as the Pacific Decadal Oscillation, the North Atlantic Oscillation and El Nino. This suggests that changes in density stratification could be a key factor explaining how large-scale atmospheric changes impact biogeochemical processes, the researchers say. Suga and Yamaguchi note further studies are needed to confirm this link. But for this to happen, continued international corroborative efforts are needed to gather global, long-term temperature and salinity data across various upper-ocean depths.
'Blob' research shows ecological effects that halted fishing and hiked whale entanglements Sacramento CA (SPX) Jan 28, 2020 An ecological pileup of unprecedented changes in the ocean off the West Coast beginning about 2014 led to record entanglements of humpback and other whales, putting the region's most valuable commercial fishery at risk, new research shows. The findings reflect a new management challenge brought about by a changing climate, recovering whale populations, and fishing pressure, according to the new research published in Nature Communications. The situation calls for new measures to alert fishermen to ... read more
|
|||||||||||||
|
|
| The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us. |
del.icio.us
Digg
Reddit
Google
