Washington, August 14 : A scientist has warned that human activities are laying the groundwork for mass extinctions in the oceans on par with vast ecological upheavals of the past.
According to Jeremy Jackson, a professor of oceanography at Scripps Institution of Oceanography at UC San Diego in the US, human activities are cumulatively driving the health of the world's oceans down a rapid spiral.
He added that only prompt and wholesale changes will slow or perhaps ultimately reverse the catastrophic problems the oceans are facing.
Jackson cites the synergistic effects of habitat destruction, overfishing, ocean warming, increased acidification and massive nutrient runoff as culprits in a grand transformation of once complex ocean ecosystems.
Areas that had featured intricate marine food webs with large animals are being converted into simplistic ecosystems dominated by microbes, toxic algal blooms, jellyfish and disease.
Jackson has tagged the ongoing transformation as "the rise of slime."
His new research paper, "Ecological extinction and evolution in the brave new ocean," is a result of his presentation last December at a biodiversity and extinction colloquium convened by the National Academy of Sciences.
"The purpose of the talk and the paper is to make clear just how dire the situation is and how rapidly things are getting worse," said Jackson.
"It's a lot like the issue of climate change that we had ignored for so long. If anything, the situation in the oceans could be worse because we are so close to the precipice in many ways," he added.
In the assessment, Jackson reviewed and synthesized a range of research studies on marine ecosystem health, and in particular key studies conducted since a seminal 2001 study he led analyzing the impacts of historical overfishing.
The new study included overfishing, but expanded to include threats from areas such as nutrient runoff that lead to so-called "dead zones" of low oxygen.
He also incorporated increases in ocean warming and acidification resulting from greenhouse gas emissions.
Jackson describes the potently destructive effects when forces combine to degrade ocean health. For example, climate change can exacerbate stresses on the marine environment already brought by overfishing and pollution.
"All of the different kinds of data and methods of analysis point in the same direction of drastic and increasingly rapid degradation of marine ecosystems," he said.
To stop the degradation of the oceans, Jackson identifies overexploitation, pollution and climate change as the three main "drivers" that must be addressed.
"The challenges of bringing these threats under control are enormously complex and will require fundamental changes in fisheries, agricultural practices and the ways we obtain energy for everything we do," he said.