Sea temperature - a micro-example

Scientifically there is no doubt that global warming exists. Not vaguely in the distant future - already here today. Still some political leaders try to shy away from reality and trumpet against facts. On the other hand, devoted scientists proceed systematically to uncover the process of climate change. My example relates to micro work, about which the scientific community does not at first shout from public platforms. They publish their findings in (sometimes obscure) scientific journals.

The results below come from a contribution in Current Biology of 31 August. “By deploying heated panels, to raise the temperature of a thin layer of water on the seabed around Rothera Research Station in the Antarctic Peninsula, the British Antarctic Survey (Bas) observed that a 1°C rise in sea temperature caused huge growth of some Antarctic seabed life to nearly double.” Note: double. The Panel on Climate Change, that has more than a thousand scientists networking globally, initially predicted a much smaller biological response to temperature change towards the year 2100.

The leader of the project at Rothera, Dr Gail Ashton, modestly stated, “This is a deceptively simple and unambiguous experiment.

“By putting our test plates in the ocean, we’ve changed nothing except the water temperature; not the food supply, not light levels, nor the surrounding ecosystem. We can see the impact of temperature change clearly - it’s quite dramatic.”

Organisms on the seabed of Antarctica live in a very cold but stable environment. Marine life has become highly adapted. An understanding of how future environmental change will affect the polar biodiversity in the ocean is a key to grasp how species may benefit from, or be damaged by even small changes in sea temperature.

Researchers monitored the settlement and growth of organisms on the panels using high-resolution photography collected by divers working in the frigid Antarctic water. Living creatures that settled on the panels included “colonial bryozoans” and “spiral tube worms”, both common to sea floors globally. Increased growth of these creatures dominated the whole system, while the rest declined in only two months. Nutrients would be more quickly available to species in the food chain, while increased skeletal growth would increase carbon capture to the sea floor.

Change in a seabed community, in response to conditions that are now expected within our lifetimes, is quite remarkable.

Much of the biodiversity in the oceans and these communities are clearly susceptible to even small changes in their environment. Understanding which species will be winners and which will be losers is a key to predict the impact of climate change on life in the ocean. The analyses will proceed for additional clarity.

During the seven years that I chaired the South African Committee for Antarctic Research (Sacar), we always kept a respectful eye on the work of Bas. (No wonder, their budget is more than twenty times larger than ours!) The Antarctic Treaty System and humankind need “deceptively simple experiments” at the micro scale to clarify the macro reality.