Archive for February 26th, 2008
It is one of the world’s strangest and smallest sea creatures, growing to no bigger than the size of a lentil.
But the tiny pteropod, with its translucent shell, could help scientists understand how marine animals will respond to the stresses of climate change.
Thousands of the molluscs, also known as sea butterflies because of their wing-like lobes, have been collected from the shallows of Antarctica.
After flying the samples thousands of kilometres to her laboratory at the University of California, Santa Barbara, marine biologist Dr Gretchen Hofmann plans to sequence the animal’s genome.
She hopes to find genes and molecular pathways that might predict how shelled creatures will respond to warmer, more acidic oceans.
Tags: biological response, phytoplankton
The Southern Ocean exerts a strong impact on marine biogeochemical cycles and global air-sea CO2 fluxes. Over the coming century, large increases in surface ocean CO2 levels, combined with increased upper water column temperatures and stratification, are expected to diminish Southern Ocean CO2 uptake. These effects could be significantly modulated by concomitant CO2-dependent changes in the region’s biological carbon pump. Here we show that CO2 concentrations affect the physiology, growth and species composition of phytoplankton assemblages in the Ross Sea, Antarctica. Field results from in situ sampling and ship-board incubation experiments demonstrate that inorganic carbon uptake, steady-state productivity and diatom species composition are sensitive to CO2 concentrations ranging from 100 to 800 ppm. Elevated CO2 led to a measurable increase in phytoplankton productivity, promoting the growth of larger chain-forming diatoms. Our results suggest that CO2 concentrations can influence biological carbon cycling in the Southern Ocean, thereby creating potential climate feedbacks.
One million tons of atmospheric carbon dioxide (CO2) are dissolved into the oceans every hour, a process that helps maintain the Earth’s delicate carbon balance. But CO2 also makes seawater more acidic, and too much of it can wreak havoc on a marine species. Three sessions at the meeting described how marine scientists are trying to assess the effects of acidification.