Bottom-dwelling sea animals play surprising role in carbon sequestration

Jeremy Hance
January 07, 2010

Researchers have long known that some marine animals, such as plankton, play big roles in the carbon cycle, but a new study shows that a long-ignored family of marine animals, the bottom-dwelling echinoderms, also do their part in the carbon cycle.

Members of the echinoderms—sea stars, sea urchins, brittle starts, sea cucumbers, and sea lilies—capture and store 0.1 gigatons of carbon annually (or 100 million tons), according to a new study in ESA Ecological Monographs. Although only about 1.8 percent of the amount of carbon humans pump into the atmosphere every year, the number is massive and surprising.

"I was definitely surprised by the magnitude of the values reported in this study, but [the study's] approach seems sound, so the reported numbers are probably fairly accurate," palaeoceanographer Justin Ries of the University of North Carolina at Chapel Hill told Nature.com.

Reis says further research should look at the effect of ocean acidification—caused by marine systems storing higher levels of carbon—on the echinoderms.

"If the echinoderms end up being disproportionately susceptible to ocean acidification then it's conceivable that the dissolving of echinoderm-derived sediments will be one of the earliest effects of ocean acidification on the global carbon cycle," says Ries. "In fact, maybe it already is."

Citation: Mario Lebrato, Debora Iglesias-Rodriguez, Richard Feely, Dana Greeley, Daniel Jones, Nadia Suarez-Bosche, Richard Lampitt, Joan Cartes, Darryl Green, Belinda Alker (2009) Global contribution of echinoderms to the marine carbon cycle: a re-assessment of the oceanic CaCO3 budget and the benthic compartments. Ecological Monographs. doi: 10.1890/09-0553.

Related articles

Oceans' ability to sequester carbon diminishing

(11/18/2009) A new study—the first of its kind—has completed an annual accounting of the oceans' intake of carbon over the past 250 years, and the news is troubling. According to the study, published in Nature, the oceans' ability to sequester carbon is struggling to keep-up with mankind's ever-growing emissions. Since 2000 researchers estimate that while every year the oceans continue to sequester more anthropogenic carbon emission, the overall proportion of carbon taken in by the oceans is declining.

Coastal habitats may sequester 50 times more carbon than tropical forests by area

(11/16/2009) Highly endangered coastal habitats are incredibly effective in sequestering carbon and locking it away in soil, according to a new paper in a report by the IUCN. The paper attests that coastal habitats—such as mangroves, sea grasses, and salt marhses—sequester as much as 50 times the amount of carbon in their soil per hectare as tropical forest. "The key difference between these coastal habitats and forests is that mangroves, seagrasses and the plants in salt marshes are extremely efficient at burying carbon in the sediment below them where it can stay for centuries or even millennia."

Shells thinning due to ocean acidification

(03/13/2009) By soaking up excess CO2 from the atmosphere oceans are undergoing a rise in acidity which is having ramifications across their ecosystems, most frequently highlighted in the plight of coral reefs around the world. However, a new study in Nature Geoscience shows that the acidification is affecting another type of marine life. Foraminifera, a tiny amoeba-like entity numbering in the billions, have experienced a 30 to 35 percent drop in their shell-weight due to the high acidity of the oceans.

Jeremy Hance
mongabay.com (January 07, 2010).

Bottom-dwelling sea animals play surprising role in carbon sequestration .