Understanding long-term trends in ocean layering

January 29, 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 Niño. 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.
-end-


Tohoku University

Related Data Articles from Brightsurf:

Keep the data coming
A continuous data supply ensures data-intensive simulations can run at maximum speed.

Astronomers are bulging with data
For the first time, over 250 million stars in our galaxy's bulge have been surveyed in near-ultraviolet, optical, and near-infrared light, opening the door for astronomers to reexamine key questions about the Milky Way's formation and history.

Novel method for measuring spatial dependencies turns less data into more data
Researcher makes 'little data' act big through, the application of mathematical techniques normally used for time-series, to spatial processes.

Ups and downs in COVID-19 data may be caused by data reporting practices
As data accumulates on COVID-19 cases and deaths, researchers have observed patterns of peaks and valleys that repeat on a near-weekly basis.

Data centers use less energy than you think
Using the most detailed model to date of global data center energy use, researchers found that massive efficiency gains by data centers have kept energy use roughly flat over the past decade.

Storing data in music
Researchers at ETH Zurich have developed a technique for embedding data in music and transmitting it to a smartphone.

Life data economics: calling for new models to assess the value of human data
After the collapse of the blockchain bubble a number of research organisations are developing platforms to enable individual ownership of life data and establish the data valuation and pricing models.

Geoscience data group urges all scientific disciplines to make data open and accessible
Institutions, science funders, data repositories, publishers, researchers and scientific societies from all scientific disciplines must work together to ensure all scientific data are easy to find, access and use, according to a new commentary in Nature by members of the Enabling FAIR Data Steering Committee.

Democratizing data science
MIT researchers are hoping to advance the democratization of data science with a new tool for nonstatisticians that automatically generates models for analyzing raw data.

Getting the most out of atmospheric data analysis
An international team including researchers from Kanazawa University used a new approach to analyze an atmospheric data set spanning 18 years for the investigation of new-particle formation.

Read More: Data News and Data Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.