20-10. Deciphering blue carbon in critical marine mineral environments

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Benthic carbon storage and sequestration in marine ecosystems represents an important carbon sink with potential to mitigate climate change.  The carbon stored in marine ecosystems can be removed from the carbon cycle for 100+ years and has been referred to “blue carbon”.  The burial of organic matter in marine sediments therefore serves as a link between active pools of carbon in the ocean, atmosphere, land, and carbon pools that cycle on geologic timescales, with significant carbon sequestration occurring in the spatially extensive abyssal plains (Ramirez-Llodra et al. 2010).  Abyssal plains, representing 50% of the world’s surface and 75% of the seafloor, also host polymetallic nodules that can be rich in metals, such as nickel, copper, cobalt, molybdenum, zirconium, lithium, and rare-earth elements (Hein et al. 2013).  Recent work has raised questions on the degree to which deep ocean organic carbon sequestration may be affected by exploration and extraction of critical minerals (Stratmann et al. 2018; Vonnahme et al. 2020).  Therefore, fundamental science questions remain regarding how organic carbon cycling and carbon sequestration varies globally among nodule fields with differing sediment organic carbon content. 

Specifically, this RO is aimed at deciphering the role of blue carbon associated with manganese nodules and host sediments, including determining the provenance of organic matter (OM) in these settings. This will enable differentiating bioavailable components of deposited organic matter, which are known to sustain diverse benthic communities, from recalcitrant components, which contribute to long-term carbon burial in the deep sea.  This proposed research opportunity will require novel and cutting-edge analytical methodologies, such as liquid chromatography (LC, HPLC), gas chromatography (GC), and mass spectrometry (MS), and nuclear magnetic resonance spectroscopy (solid-state ¹³C NMR), including but not limited to lipid and amino acid biomarkers and compound-specific isotope analysis that represent powerful approaches to trace the origin of OM.  Sediment samples will be collected as part of an ongoing systematic box core sampling program that will take advantage of ship time opportunities provided to USGS and BOEM by federal, industry, international, and academic partners.  Ultimately this research will contribute to answering questions regarding how much blue carbon is in critical marine mineral environments and what deep-water habitats contain the blue carbon, to evaluate potential impacts of sea-bed mining to blue carbon storage in critical marine mineral environments and what ecosystem management goals are needed to maintain blue carbon ecosystems.

Interested applicants are strongly encouraged to contact the Research Advisor(s) early in the application process to discuss project ideas.

References:

Hein JR, Mizell K, Koschinsky A, Conrad TA. 2013. Deep-ocean mineral deposits as a source of critical metals for high-and green-technology applications: Comparison with land-based resources. Ore Geology Reviews. 51:1-14.

Ramirez-Llodra E, Brandt A, Danovaro R, De Mol B, Escobar E, German CR, Levin LA, Martinez Arbizu P, Menot L, Buhl-Mortensen P et al. 2010. Deep, diverse and definitely different: Unique attributes of the world's largest ecosystem. Biogeosciences. 7(9):2851-2899.

Stratmann T, Lins L, Purser A, Marcon Y, Rodrigues CF, Ravara A, Cunha MR, Simon-Lledó E, Jones DOB, Sweetman AK. 2018. Abyssal plain faunal carbon flows remain depressed 26 years after a simulated deep-sea mining disturbance. Biogeosciences. 15(13):4131-4145.

Vonnahme TR, Molari M, Janssen F, Wenzhöfer F, Haeckel M, Titschack J, Boetius A. 2020. Effects of a deep-sea mining experiment on seafloor microbial communities and functions after 26 years. Science Advances. 6(18):eaaz5922.

Proposed Duty Station: Santa Cruz, California

Areas of PhD: Geology, geochemistry, organic chemistry, biology, or related fields (candidates holding a Ph.D. in other disciplines, but with extensive knowledge and skills relevant to the Research Opportunity may be considered).

Qualifications: Applicants must meet the basic qualifications for one of the following:  Research Chemist, Research Oceanographer, or Research Geologist.

(This type of research is performed by those who have backgrounds for the occupations stated above.  However, other titles may be applicable depending on the applicant's background, education, and research proposal. The final classification of the position will be made by the Human Resources specialist.)

Human Resources Office Contact:  Veronica Guerrero-Nunez, 916-278-9405, vguerreronunez@usgs.gov