Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ocean warming and oxygen loss are putting marine life under more and more pressure

05.06.2015

If you want to live, you need to breathe and muster enough energy to move, find nourishment and reproduce. This basic tenet is just as valid for us human beings as it is for the animals inhabiting our oceans. Unfortunately, most marine animals will find it harder to satisfy these criteria, which are vital to their survival, in the future.

That was the key message of a new study recently published in the journal Science, in which American and German biologists defined the first universal principle on the combined effects of ocean warming and oxygen loss on the productivity of marine life forms.


The Polar cod Boreogadus saida.

Photo: Hauke Flores, Alfred-Wegener-Institut

Their conclusion: as climate change progresses, these animals will be hard-pressed to satisfy their oxygen and energetic requirements in their changing native habitats. As a result, these species will migrate to cooler regions or deeper waters, ecosystems will be disrupted, and the diversity of species will decline.

In order to be able to make more precise and globally applicable prognoses concerning the effects of climate change on life in our oceans, marine biologists have long sought to find universal principles that would allow them to describe the living conditions in the oceans and at their borders. In this regard, one of the key questions is: How will the warming of the oceans and resultant decrease in dissolved oxygen impact marine life forms’ productivity?

As marine biologist Prof Hans-Otto Pörtner from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Science, who co-authored the article, explains, “If an animal has to do more work, it costs energy that it somehow has to produce over and above its resting metabolic rate. Marine life forms generate this additional energy by breathing and thereby taking up more oxygen. However, their ability to do so depends on two factors: the water temperature, and how sensitive the species is to lack of oxygen.”

In their new study, he and his American colleagues Curtis Deutsch, Brad Seibel, Aaron Ferrel and Raymond B. Huey calculated the ability of selected animal species to increase their metabolic rate, then examined that ability in relation with the temperatures and oxygen concentrations in the world’s oceans. This approach allowed them to create a metabolic index for each species, which sets clearly defined limits for oxygen-breathing sea life:

“Marine animals like eelpouts, rock crabs and Atlantic cod can only survive in environments with enough oxygen for them to increase their metabolism to between two and five times their resting metabolic rate if need be. Every species has a certain maximum temperature to survive, and a certain minimum oxygen level, and the two requirements are related,” says lead author Curtis Deutsch from the University of Washington.

As such, the ongoing climate change poses the following problem for marine animals: the warmer the water gets, the less oxygen it can absorb and store. At the same time, in warmer water the animals will need more energy and oxygen to maintain their resting metabolic rate. This means the warmer the oceans become, the less able its inhabitants will be to boost their metabolism to between two and five times their resting metabolic rate, which is what allows them to move, seek food and reproduce.

“If the oxygen level in a given region of the ocean drops below a species’ minimum requirements, it forces the animals to abandon their native habitat. This combines with the effect of warmer temperatures. Since animals evade to cooler regions, their habitat shifts towards the poles or to greater water depths. In Atlantic cod and many other fish species, we can already observe the shift now,” says Hans-Otto Pörtner.

In their study, the authors provide habitat-shift prognoses for all latitudes. As Hans-Otto Pörtner adds: “Further, the phenomenon is even more pronounced in those regions hit by additional oxygen loss, for instance due to increasing water stratification or because human beings release more nutrients into the ocean, promoting the growth of oxygen-stealing microorganisms.”

The researchers expect to see the most apparent changes in the polar seas. “The water in the Arctic and Antarctic Oceans is extremely cold, but also very rich in oxygen. Thanks to evolution, the animals living there have adapted to these conditions and will have little chance to adjust when the combination of warming and lower oxygen levels hits. Instead, species that immigrate from areas with higher water temperatures and lower oxygen concentrations will establish themselves and displace the native polar species,” says Hans-Otto Pörtner.

In the northern Pacific, for example, researchers are already observing a more extreme drop in oxygen concentrations than was expected due to warming alone. In this type of ocean region, the species’ geographic range is reduced drastically, which of course also means significant consequences for the fishing industry.

From a research perspective, the new metabolic index concept can potentially facilitate better prognoses. “We now have a universal approach that allows us to more precisely identify climate-related changes in the geographic range and productivity of a given species,” explains Hans-Otto Pörtner. Now it’s up to the scientific community to investigate the metabolic index and its limits for further species; if they do, Pörtner is confident that: “Bit by bit, we’ll arrive at a far more complete image of what we outlined in our study.”

Notes for Editors:
The study will be published on Friday, the 5th of June 2015 in Science with following title:
Curtis Deutsch, Aaron Ferrel, Brad Seibel, Hans-Otto Pörtner, Raymond B. Huey: Climate change tightens a metabolic constraint on marine habitats, Science 5-Jun-2015

Printable images can be found here: http://www.awi.de/en/news/press_releases/

Your contact in the AWI media team is Sina Löschke (Tel: +49 471 4831 2008; E-Mail: medien(at)awi.de).

The Alfred Wegener Institute conducts research in the Arctic, Antarctic and oceans of the high and mid-latitudes. It coordinates polar research in Germany and provides major infrastructure to the international scientific community, such as the research icebreaker Polarstern and stations in the Arctic and Antarctica. The Alfred Wegener Institute is one of the 18 research centres of the Helmholtz Association, the largest scientific organisation in Germany.

Ralf Röchert | idw - Informationsdienst Wissenschaft

More articles from Life Sciences:

nachricht Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

nachricht The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>