“The biological pump”: Hang around biological oceanographers for a while and they might not mention it, but if you ask them about it, their eyes will light up and they might exclaim, “Oh! That’s how all the stuff from the surface sinks to the deep!”
The “stuff” is mostly algae, bacteria, and other microbial life. Unlike terrestrial environments, where biomass (e.g., plants) turns over on quite long time-scales, in the ocean most life is single-celled and the average “life span” is on the order of a few days, since most of these microbes are either eaten, infected by viruses, or otherwise die and sink to the deep ocean (if they’re dense enough themselves or attached to things that are). Thus, the biological pump is the mechanism by which the ocean interacts with and influences Earth’s climate, capturing a portion of the carbon dioxide produced by human activities, storing it in cellular biomass, and exporting it to the deep ocean and deep ocean sediments—storing it, in some cases, for thousands of years.
On our research cruise from May 17th to 19th, we studied processes involved in the degradation of biomass produced at the surface which sinks to the deep ocean and becomes part of the sediments. For this particular cruise, our goals were mostly retrieval of experiments set out on the seafloor months ago, but we also deployed a new experiment on the seafloor.” Due to the cold temperatures in the deep sea and seafloor (about the same as your refrigerator at home), life is slower than at the surface, and experiments often need to be carried out for months or years to observe a response.
The cruise involved three research groups, MBARI’s Marine Microbial Ecology Group, led by Alexandra Worden; the Dekas Lab from Stanford University; and the Orphan Lab from the California Institute of Technology.