[32Si Profiles - from RR1813] - 32Si data from EXPORTS cruise RR1813 on R/V Roger Revelle in the Subarctic North Pacific near Station PAPA from August to September 2018 (Collaborative Research: Diatoms, Food Webs and Carbon Export - Leveraging NASA EXPORTS to Test the Role of Diatom Physiology in the Biological Carbon Pump)

This dataset includes depth profiles in the euphotic zone of nutrient (nitrate, silicate, phosphate) concentrations and profiles of silicic acid uptake rates from EXPORTS cruise RR1813. \r\n\r\nThe EXPORTS field campaign in the subarctic North Pacific sampled an ecosystem characterized as high nutrient low chlorophyll (HNLC) due to low iron (Fe) levels that are primary controllers constraining phytoplankton utilization of other nutrients.

It has been a paradigm in low Fe, HNLC systems that diatoms grow at elevated Si:C and Si:N ratios and should be efficiently exported as particles significantly enriched in Si relative to C. However, Fe limitation also alters diatoms species composition and the high Si demand imposed by low Fe can drive HNLC regions to Si limitation or Si/Fe co-limitation. Thus, the degree of Si and/or Fe stress in HNLC waters can all alter diatom taxonomic composition, the elemental composition of diatom cells, and the path cells follow through the food web ultimately altering diatom carbon export.\r\n\r\nWithin each ecosystem state examined in the EXPORTS program, nutrient biogeochemistry, diatom and phytoplankton community structure, and global diatom gene expression patterns (metatranscriptomics) are characterized in the lit ocean.