Habitability and Distribution of Subseafloor Life in Oceanic Basement
Abstract
Previous estimates of the microbial biomass contained within the ocean basement vary by over two orders of magnitude and range from 1.5 - 200 Gt of carbon. We explore the likelihood of these previous estimates, as well as the habitability and distribution of subseafloor life in ocean basement, through various steps. First, we combine global models of heat flow and sediment thickness to identify the depth to specific isotherms within the basement (e.g., 20˚C, 45˚C, 80˚C and 122˚C). Second, we apply various models of ocean crust porosity to account for decreases in porosity as a function of depth into basement and basement age. The combination of isotherm information and basement porosity provide an estimate of the volume of "open" space available for microbial biomass to occupy for each isotherm interval. We then combine previous estimates of planktonic and biofilm cell abundance within the basement to calculate the number of microbial cells within each isotherm interval. Finally, we assume 24 fg C/cell to calculate the interval and total biomass. Our initial results are more consistent with the lower estimates of microbial biomass for basement temperatures less than 122˚C. Our analysis also indicates the habitable regions for microbes are skewed toward younger ocean basement and that the cumulative habitable volumes for psychophiles, mesophiles, thermophiles, and hyperthermophiles are very similar.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.V11E0067P
- Keywords:
-
- 1050 Marine geochemistry;
- GEOCHEMISTRYDE: 3613 Subduction zone processes;
- MINERALOGY AND PETROLOGYDE: 3617 Alteration and weathering processes;
- MINERALOGY AND PETROLOGYDE: 4806 Carbon cycling;
- OCEANOGRAPHY: BIOLOGICAL AND CHEMICAL