Insight into marine life's ability to adapt to climate change

EurekAlert via the University of Plymouth: A study into marine life around an underwater volcanic vent in the Mediterranean, might hold the key to understanding how some species will be able to survive in increasingly acidic sea water should anthropogenic climate change continue.

Researchers have discovered that some species of polychaete worms are able to modify their metabolic rates to better cope with and thrive in waters high in carbon dioxide (CO2), which is otherwise poisonous to other, often closely-related species. The study sheds new light on the robustness of some marine species and the relative resilience of marine biodiversity should atmospheric CO2 continue to cause ocean acidification.

A team of scientists led by Plymouth University, and including colleagues from the Naples Zoological Station in Ischia; the Marine Ecology Laboratory ENEA in La Spezia, Italy; the University of Texas Galveston; and the University of Hull, conducted a three-year research project into the potential mechanisms that species of worm polychaetes use to live around the underwater CO2 vent of Ischia in Southern Italy.

...They monitored the responses of the worms and found that one of the species that had been living inside the CO2 vent was physiologically and genetically adapted to the acidic conditions, whilst another was able to survive inside the vent by adjusting its metabolism.

...The results revealed that species normally found inside the CO2 vent were better able to regulate their metabolic rate when exposed to high CO2 conditions, whilst species only found outside the CO2 vent were clearly impaired by acidic waters. In fact, their metabolism either greatly decreased, indicating reduced energy production, or greatly increased, indicating a surge in the basic cost of living, in both cases making life inside the vent unsustainable.

Dr Maria-Cristina Gambi, of the Naples Zoological Station in Ischia, explained: "Despite some species showing the ability to metabolically adapt and adjust to the extreme conditions that are found inside the CO2 vents, others appear unable to physiologically cope with such conditions. In this sense, our findings could help to explain mass extinctions of the past, and potential extinctions in the future, as well as shed light on the resilience of some species to on-going ocean acidification."...

Sully Vent in the Main Endeavour Vent Field of the northeastern Pacific Ocean. Shot by NOAA, public domain

Rising levels of acids in seas may endanger marine life

Fiona Harvey in the Guardian (UK): Rapidly rising carbon dioxide levels in the atmosphere are causing a potential catastrophe in our oceans as they become more acidic, scientists have warned. Hans Poertner, professor of marine biology at the Alfred Wegener Institute in Germany, and co-author of a new study of the phenomenon, told the Guardian: "The current rate of change is likely to be more than 10 times faster than it has been in any of the evolutionary crises in the earth's history."

Seawater is naturally slightly alkaline, but as oceans absorb CO2 from the air, their pH level falls gradually. Under the rapid escalation of greenhouse gas emissions, ocean acidification is gathering pace and many forms of marine life – especially species that build calcium-based shells – are under threat.

Poertner said that if emissions continue to rise at "business as usual" rates, this would be potentially catastrophic for some species. Acidification is just one of a broader range of the problems facing the oceans and the combination of different effects is increasing the threat. Poertner said: "We are already seeing warm water coral reefs on a downslide due to a combination of various stressors, including [rising] temperature. Ocean acidification is still early in the process [but] it will exacerbate these effects as it develops and we will see more calcifying species suffering."

However, the process of acidification takes decades and the worst effects on some species could still be avoided if emissions are urgently reduced. "The ocean is changing already, mostly due to temperature – acidification will exacerbate those effects," Poertner said.

Evidence from prehistoric ocean life provides a comparison. "The [effects observed] among invertebrates resembles those seen during the Permian Triassic extinctions 250m years ago, when carbon dioxide was also involved. The carbon dioxide range at which we see this sensitivity [to acidification] kicking in are the ones expected for the later part of this century and beyond."...

Crustacean wagon in Morgan's Slough. I believe it's...man-made!  Shot by Mette Batterton, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Greenhouse ocean may downsize fish risking one of world's most productive fisheries

The Bering Sea, one of the world's most active fishing grounds, is changing according to this story in Science Daily: ... The Bering Sea is highly productive thanks mainly to diatoms, a large type of phytoplankton. "Because they're large, diatoms are eaten by large zooplankton, which are then eaten by large fish," Hutchins explained.

The scientists found that greenhouse conditions favored smaller types of phytoplankton over diatoms. Such a shift would ripple up the food chain: as diatoms become scarce, animals that eat diatoms would become scarce, and so forth. "The food chain seems to be changing in a way that is not supporting these top predators, of which, of course, we're the biggest," Hutchins said.