Nova Mieszkovska from the Marine Biological Association of the United Kingdom said her study showed invasive species of marine macroalgae spread at 50 kilometers (31 miles) per decade -- a distance far greater than that covered by invasive terrestrial plants.

Mieszkovska said the difference might be due global warming and the resulting rapid dispersion of macroalgae propagules in the ocean.

The research was presented Tuesday in Valencia, Spain, during the opening presentations at the First World Conference on Marine Biodiversity.

"Overwhelming evidence of an accelerating deterioration of the oceans has provided the impetus to call the marine biodiversity scientific community together in this first World Conference," said Carlos Duarte, co-chairman of the conference that is co-sponsored by the Spanish Council of Scientific Research and the European Network of Excellence on Marine Biodiversity.

Duarte said the convergence of pressures on the ocean is leading to a global erosion of marine biodiversity, in which "climate change may deliver the coupe de grace for a catastrophic collapse."

More than 500 scientists from 45 nations were expected to attend the meeting.