Preventing water crises
Küldés e-mailben Facebook Twitter Nyelvváltás
Preventing water crises

Dropping oxygen levels of the oceans to cause ecological crisis

It is a lesser known fact that climate change is also making the oxygen levels of the oceans drop. Over the last 50 years, the average oxygen content of the world’s oceans has dropped by almost 2%, which may have dramatic consequences.

Today, the area of oceanic zones with insufficient oxygen to sustain life are growing. Something similar occurred 420 million years ago, during the so-called Lau/Kozlowskii extinction event: 23% of marine life forms went extinct due to the reduced level of oxygen.

The Lau/Kozlowskii extinction event is a long-standing subject of dispute among scientists, as it was not associated with any specific occurrence such as a massive volcanic eruption or meteor impact. Researchers at Florida State University (FSU) believed it was particularly important to study that extinction because a similar global decline in biodiversity is taking place today, so the research may shed light on the potential outcomes of various present climate scenarios.

The researchers at FSU measured the quantity of thallium and sulphur isotopes and the concentration of manganese in sediment samples collected in Lithuania and Sweden, and used the data to establish a precise timeline of the decline in oceanic oxygen levels.

The research has established a clear link between mass extinction and the drop in oxygen levels. During the event, deep sea creatures died out first, then oxygen was depleted in shallower waters too, and the concentration of sulphurous compounds also grew to make the oceans even less habitable.

The link between the extinction 420 million years ago and the lack of oxygen in the water paints a bleak picture of the future: the recent, relatively fast 2% drop in the oxygen level of the oceans foreshadows an ecological crisis.

Lack of oxygen represents severe stress for living organisms, so we must not disregard this consequence of climate change Photo: Shutterstock
Further information: Florida State University

Corals back from the dead discovered in the Mediterranean Sea

For the first time ever, living polyps were discovered in Mediterranean coral colonies that were previously thought to be completely dead by researchers who published their finding in the periodical Science Advances.

Oceans absorb massive quantities of carbon dioxide

The oceans play a very important role in controlling Earth’s climate. New research has shown that the planet’s five oceans absorb much more carbon dioxide, one of the gases responsible for the greenhouse effect, than previously thought.

Temperatures in Israel increase by 0.25 degrees Celsius per decade

According to a study published in the International Journal of Climatology, Israel’s average temperature has been rising continuously since the proclamation of the Middle Eastern state in 1948, but over the last thirty years the rate of warming has also increased.

Temperatures increase much faster than global average in the Mediterranean region

Temperatures are rising much faster than the global average in the region of the Mediterranean Sea, and this represents a threat to the food and water resources of the region, researchers have warned in a new study.

Fates, faces, contrasts

The news about climate refugees are alternating sequences of frightening numbers and apocalyptic landscapes that obscure the real face of the problem: the disfigured human fates.

Climate change causing great damage to UK wildlife

More than a quarter of all mammals are threatened with extinction.

Several hundred temperature records broken in 2019

Between 1 May and 30 August, higher than ever temperatures have been measured in 29 countries, on almost 400 occasions in the Northern Hemisphere.

The perishing glaciers of the Alps – shown from a special perspective

The French falconer Jacques-Olivier Travers has surveyed the glaciers of the Alps using a camera attached to a white-tailed eagle.

The Polarstern sets off on a unique expedition frozen to an ice floe

The ice floe that the German research boat will be attached to as it drifts around the Arctic for almost a year on the most important Arctic expedition ever has been selected.

September 2019 the warmest so far

Data from European climate researchers indicates that this year’s was the warmest September since the Copernicus Climate Change Service began keeping regular records of meteorological data in 1981.