We would like to inform you about a new global synthesis product of seafloor surficial carbonate, which follows early work by Archer (1996). To interface with climate and circulation models, ocean substrates data have been gridded from dbSEABED (Information Integration System for Marine Substrates) at the global scale, at a 1/10° resolution. The new mapping suggests lower carbonate contents overall than mapped in earlier works. This may affect modeled budgets for earth-system carbon dioxide and outcomes for ocean acidification. 

Compared to Archer’s atlas of the distribution of calcium carbonate in sediments of the deep sea published in 1996, there is a number of changes in this carbon synthesis product:

• The amount of data available is much greater, now millions of samples and sites.
• The core-top criterion is relaxed (based on arguments involving bioturbation, erosion, management of core over-penetrations in underlying database). More sampling types are included: grabs and dredges, scuba and submersible dives.
• Exposed rock areas (such as the spreading ridges) and Fe-Mn nodule grounds are accounted for.
• Shallow-water areas, which also play a role in ocean carbonate chemistry (Andersson & Mackenzie, 2012. "Revisiting four scientific debates in ocean acidification research", Biogeosciences. 9, 893-905) are mapped. Prime amongst the shallow water areas is the "Coral Triangle" area of SE-Asia, Indonesia.
  

For more information and to view the product, please visit this site.

The graphic below is a sample showing the global-scale carbonate contents, interpolated using Radial Basis Function methods. Deep blue to dark red, 0 to 100%.

The dbSEABED data are rapidly being extended and new griddings are generated on request. Some geographic data on the regional distributions of skeletal carbonate types and mineralogies are also available from the project. Furthermore, leads of this mapping project are seeking collaborations with chemical oceanographers.  

Contact: Chris Jenkins, Univ. Colorado, Boulder (This email address is being protected from spambots. You need JavaScript enabled to view it.)