PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Ocean's harmful low-oxygen zones growing, are sensitive to small changes in climate

2011-06-19
(Press-News.org) Fluctuations in climate can drastically affect the habitability of marine ecosystems, according to a new study by UCLA scientists that examined the expansion and contraction of low-oxygen zones in the ocean.

The UCLA research team, led by assistant professor of atmospheric and oceanic sciences Curtis Deutsch, used a specialized computer simulation to demonstrate for the first time that the size of low-oxygen zones created by respiring bacteria is extremely sensitive to changes in depth caused by oscillations in climate. These oxygen-depleted regions, which expand or contract depending on their depth, pose a distinct threat to marine life.

"The growth of low-oxygen regions is cause for concern because of the detrimental effects on marine populations — entire ecosystems can die off when marine life cannot escape the low-oxygen water," said Deutsch. "There are widespread areas of the ocean where marine life has had to flee or develop very peculiar adaptations to survive in low-oxygen conditions."

The study, which was published June 9 in the online edition the journal Science and will be available in an upcoming print edition, also showed that in addition to consuming oxygen, marine bacteria are causing the depletion of nitrogen, an essential nutrient necessary for the survival of most types of algae.

"We found there is a mechanism that connects climate and its effect on oxygen to the removal of nitrogen from the ocean," Deutsch said. "Our climate acts to change the total amount of nutrients in the ocean over the timescale of decades."

Low-oxygen zones are created by bacteria living in the deeper layers of the ocean that consume oxygen by feeding on dead algae that settle from the surface. Just as mountain climbers might feel adverse effects at high altitudes from a lack of air, marine animals that require oxygen to breathe find it difficult or impossible to live in these oxygen-depleted environments, Deutsch said.

Sea surface temperatures vary over the course of decades through a climate pattern called the Pacific Decadal Oscillation, during which small changes in depth occur for existing low-oxygen regions, Deutsch said. Low-oxygen regions that rise to warmer, shallower waters expand as bacteria become more active; regions that sink to colder, deeper waters shrink as the bacteria become more sluggish, as if placed in a refrigerator.

"We have shown for the first time that these low-oxygen regions are intrinsically very sensitive to small changes in climate," Deutsch said. "That is what makes the growth and shrinkage of these low-oxygen regions so dramatic."

Molecular oxygen from the atmosphere dissolves in sea water at the surface and is transported to deeper levels by ocean circulation currents, where it is consumed by bacteria, Deutsch said.

"The oxygen consumed by bacteria within the deeper layers of the ocean is replaced by water circulating through the ocean," he said. "The water is constantly stirring itself up, allowing the deeper parts to occasionally take a breath from the atmosphere."

A lack of oxygen is not the only thing fish and other marine life must contend with, according to Deutsch. When oxygen is very low, the bacteria will begin to consume nitrogen, one of the most important nutrients that sustain marine life.

"Almost all algae, the very base of the food chain, use nitrogen to stay alive," Deutsch said. "As these low-oxygen regions expand and contract, the amount of nutrients available to keep the algae alive at the surface of the ocean goes up and down."

Understanding the causes of oxygen and nitrogen depletion in the ocean is important for determining the effect on fisheries and fish populations, he said.

Deutsch and his team used a computer model of ocean circulation and biological processes that produce or consume oxygen to predict how the ocean's oxygen distribution has changed over the past half century. The researchers tested their predictions using observations made over the last several decades, specifically targeting areas where oxygen concentration is already low, because marine life in these areas will feel the changes most quickly.

How would rising global temperatures affect these low-oxygen environments?

As temperature increases, less oxygen leaves the atmosphere to dissolve in the ocean, Deutsch explained. Additionally, the shallower levels of the ocean heat up and become more buoyant, slowing the oxygen circulation to lower layers.

"In the case of a global temperature increase, we expect that low-oxygen regions will grow in size, similar to what happened at the end of the last ice age 30,000 years ago," Deutsch said. "Since these regions change greatly in size from decade to decade due to the Pacific Decadal Oscillation, more data is required before we can recognize an overall trend.

"Global warming will almost certainly influence the amount of oxygen in the ocean, but we expect it to be a slow effect that takes place over long periods of time," he added. "There are huge changes in the volume of this low-oxygen water, but the changes oscillate in a natural cycle instead of a persistent growth as many expected. Oxygen comes and goes in the ocean in a way that is not attributable to the long-term warming of the planet. Instead, it is part of the natural rhythm of the ocean."

INFORMATION:

The study was funded by the National Science Foundation, as well as by the Gordon and Betty Moore Foundation.

Co-authors include UCLA researchers Holger Brix and Hartmut Frenzel, assistant professor Taka Ito at Colorado State University, and professor LuAnne Thompson at the University of Washington.

UCLA is California's largest university, with an enrollment of nearly 38,000 undergraduate and graduate students. The UCLA College of Letters and Science and the university's 11 professional schools feature renowned faculty and offer more than 323 degree programs and majors. UCLA is a national and international leader in the breadth and quality of its academic, research, health care, cultural, continuing education and athletic programs. Six alumni and five faculty have been awarded the Nobel Prize.

For more news, visit the UCLA Newsroom and UCLA News|Week and follow us on Twitter.

END



ELSE PRESS RELEASES FROM THIS DATE:

Graphene may gain an 'on-off switch,' adding semiconductor to long list of material's achievements

Graphene may gain an on-off switch, adding semiconductor to long list of materials achievements
2011-06-19
College Park, MD (June 17, 2011)--A team of researchers has proposed a way to turn the material graphene into a semiconductor, enabling it to control the flow of electrons with a laser "on-off switch". Graphene is thinnest and strongest material ever discovered. It's a layer of carbon atoms only one-atom thick, but 200 times stronger than steel. It also conducts electricity extremely well and heat better than any other known material. It is almost completely transparent, yet so dense that not even atoms of helium can penetrate it. In spite of the impressive list of promising ...

Madagascar marine resources plundered by international seafood markets

2011-06-19
Fish catches in Madagascar over the last half-century are double the official reports, and much of that fish is being caught by unregulated traditional fishers or accessed cheaply by foreign fishing vessels. Seafood exports from Madagascar often end up in a European recipe, but are a recipe for political unrest at home, where two-thirds of the population face hunger. These are the findings of a recent study led by researchers from the University of British Columbia's Sea Around Us Project in collaboration with the Madagascar-based conservation organisation Blue Ventures. ...

Not just another brick in the (plant cell) wall

Not just another brick in the (plant cell) wall
2011-06-19
Co-author Professor Tony Bacic from the ARC Centre of Excellence in Plant Cell Walls, School of Botany and the Bio21 Institute, at the University of Melbourne, said plant cell walls (plant biomass) represent the world's largest renewable resource. "Plant sciences have become a major new driver of international research due to their central role as renewable sources of transport fuels, as functional foods to improve human health, and as a source of raw materials for industrial processes," he said. The study has been published in the current issue of the international ...

First X-ray lasing of SACLA

2011-06-19
RIKEN and the Japan Synchrotron Radiation Research Institute (JASRI) have successfully produced a first beam of X-ray laser light with a wavelength of 1.2 Angstroms. This light was created using SACLA, a cutting-edge X-ray Free Electron Laser (XFEL) facility unveiled by RIKEN in February 2011 in Harima, Japan. SACLA (SPring-8 Angstrom Compact free electron LAser) opens a window into the structure of atoms and molecules at a level of detail never seen before. The use of ultra high-intensity X-ray free electron laser light to explore the miniature structure of matter, until ...

The way you relate to your partner can affect your long-term mental and physical health, study shows

2011-06-19
The potentially lasting implications of day-to-day couple conflict on physical and mental well-being are revealed in a study published today in the journal Personal Relationships. Until now research has concentrated on the immediate effects of romantic conflict, typically in controlled laboratory settings. In one of the first studies to look at the longer term, Professor Angela Hicks investigated the physiological and emotional changes taking place in couples the day after conflict occurred, specifically taking into account the differing styles of emotional attachment ...

World Health Organization releases latest Dengue Bulletin

2011-06-19
Luiz Tadeu Moraes Figuedo's paper on dengue in Brazil confirms the country's worsening trend; from 1999-2009, where cases rose at 6.2% per year and dengue deaths at 12.0% per year. Carmen Perez and co-workers, reporting on dengue vector control in Puerto Rico, found that 83% of the costs ($1.97 per person per year) were funded by the lowest and often the least financed level of government: municipalities. Examining dengue cases imported into France, Guy LaRuche documented the alarming increase in cases originating from Cote d'Ivoire from only one case in 2006-07 to ...

No healing in a vacuum

2011-06-19
Negative-pressure wound therapy probably does not promote healing. This is the conclusion of Frank Peinemann and Stefan Sauerland's meta-analysis in the current edition of Deutsches Ärzteblatt International (Dtsch Arztebl Int 2011; 108[22]: 381-9). In negative-pressure wound therapy (NPWT), wounds are covered with an airtight film and an adjustable negative pressure is applied using an electronically controlled pump. The negative pressure drains wound exudate and is thought to promote healing. This procedure is used in particular for chronic persistent wounds and complicated ...

'Lost' bats found breeding on Scilly

Lost bats found breeding on Scilly
2011-06-19
A University of Exeter biologist has discovered a 'lost' species of bat breeding on the Isles of Scilly (UK). A pregnant female brown long-eared bat is the first of its species to be found on the islands for at least 40 years. It was discovered by Dr Fiona Mathews, Senior Lecturer at the University of Exeter, a postgraduate student and a team from the Wiltshire Bat Group. The Scilly Isles Bat Group called in Dr Mathews and her team to help them find out more about bats on the islands. The researchers set up a radiotracking study, with funding from the Isles of Scilly ...

Discovery of a new mechanism of gene control that is associated with cancer

2011-06-19
Researchers headed by Joan Massagué at Memorial Sloan-Kettering Cancer Center (MSKCC) in New York and by María Macías at the Institute for Research in Biomedicine (IRB Barcelona) have identified a complex mechanism by which some proteins that are essential for life, called Smads, regulate the activity of genes associated with cancer. The fruit of three years of intense work, the study reports on the life cycle of this protein, a process that ensures that the protein is destroyed when it has completed its function. These results have been published today in the top journal ...

A better way to remember

A better way to remember
2011-06-19
Scientists and educators alike have long known that cramming is not an effective way to remember things. With their latest findings, researchers at the RIKEN Brain Science Institute in Japan, studying eye movement response in trained mice, have elucidated the neurological mechanism explaining why this is so. Published in the Journal of Neuroscience, their results suggest that protein synthesis in the cerebellum plays a key role in memory consolidation, shedding light on the fundamental neurological processes governing how we remember. The "spacing effect", first discovered ...

LAST 30 PRESS RELEASES:

Plant doctor: An AI system that watches over urban trees without touching a leaf

Study tracks chromium chemistry in irradiated molten salts

Scientists: the beautiful game is a silver bullet for global health

Being physically active, even just a couple of days a week, may be key to better health

High-fat diet promote breast cancer metastasis in animal models

A router for photons

Nurses and AI collaborate to save lives, reduce hospital stays

Multi-resistance in bacteria predicted by AI model

Tinker Tots: A citizen science project to explore ethical dilemmas in embryo selection

Sensing sickness

Cost to build multifamily housing in California more than twice as high as in Texas

Program takes aim at drinking, unsafe sex, and sexual assault on college campuses

Inability to pay for healthcare reaches record high in U.S.

Science ‘storytelling’ urgently needed amid climate and biodiversity crisis

KAIST Develops Retinal Therapy to Restore Lost Vision​

Adipocyte-hepatocyte signaling mechanism uncovered in endoplasmic reticulum stress response

Mammals were adapting from life in the trees to living on the ground before dinosaur-killing asteroid

Low LDL cholesterol levels linked to reduced risk of dementia

Thickening of the eye’s retina associated with greater risk and severity of postoperative delirium in older patients

Almost one in ten people surveyed report having been harmed by the NHS in the last three years

Enhancing light control with complex frequency excitations

New research finds novel drug target for acute myeloid leukemia, bringing hope for cancer patients

New insight into factors associated with a common disease among dogs and humans

Illuminating single atoms for sustainable propylene production

New study finds Rocky Mountain snow contamination

Study examines lactation in critically ill patients

UVA Engineering Dean Jennifer West earns AIMBE’s 2025 Pierre Galletti Award

Doubling down on metasurfaces

New Cedars-Sinai study shows how specialized diet can improve gut disorders

Making moves and hitting the breaks: Owl journeys surprise researchers in western Montana

[Press-News.org] Ocean's harmful low-oxygen zones growing, are sensitive to small changes in climate