Jorge L. Sarmiento

Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms

Todays surface ocean is saturated with respect to calcium carbonate, but increasing atmospheric carbon dioxide concentrations are reducing ocean pH and carbonate ion concentrations, and thus the level of calcium carbonate saturation. Experimental evidence suggests that if these trends continue, key marine organisms—such as corals and some plankton—will have difficulty maintaining their external calcium carbonate skeletons. Here we use 13 models of the ocean–carbon cycle to assess calcium carbonate saturation under the IS92a ‘business-as-usual’ scenario for future emissions of anthropogenic carbon dioxide. In our projections, Southern Ocean surface waters will begin to become undersaturated with respect to aragonite, a metastable form of calcium carbonate, by the year 2050. By 2100, this undersaturation could extend throughout the entire Southern Ocean and into the subarctic Pacific Ocean. When live pteropods were exposed to our predicted level of undersaturation during a two-day shipboard experiment, their aragonite shells showed notable dissolution. Our findings indicate that conditions detrimental to high-latitude ecosystems could develop within decades, not centuries as suggested previously.

SOCCOM float data - Snapshot 2016-10-03. In Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) Float Data Archive.

This .zip archive contains Quality Controlled float data for biogeochemical profiling floats deployed by the Southern Ocean Carbon and Climate Observation and Modeling (SOCCOM) program. Data were processed by the SOCCOM data management team at the Monterey Bay Aquarium Research Institute (MBARI). Certain early archives may contain additional University of Washington/MBARI floats deployed outside of the SOCCOM array. n FORMAT: n The ascii files contained herein were formatted to be compatible with Ocean Data View (ODV). ODV is freely available at https://odv.awi.de/. In addition, a Matlab function has been provided in each .zip archive for parsing the .txt files into data structures within Matlab (see get_FloatViz_data.m). Please note that the data files within this .zip archive represent a snapshot of all SOCCOM float data processed at MBARI as of the date listed in the file name. Therefore, be aware that processing updates (** AND THUS CHANGES TO THE DATA **) may have occurred since the time the snapshot was created. For the most up-to-date files (processed every 4 hours), visit ftp://ftp.mbari.org/pub/SOCCOM/FloatVizData/ or http://www.mbari.org/science/upper-ocean-systems/chemical-sensor-group/floatviz/ n ALTERNATE FORMATS: NetCDF and Matlab n Lynne Talley has provided alternate formats, NetCDF and Matlab, for the ODV text data. Matlab and NetCDF formatted files are provided for each ODV text file. n The Matlab format is loaded as structure, FloatViz, with the ODV parameter names as the structures fieldnames. n The NetCDF format is similar to ARGO Float NetCDF format in its structure. The parameter names, however, match the ODV text parameter names. In addition to the quality control flag strings that ARGO profiles use, an array of quality control flags is provided in the NetCDF files for programming convenience. n PARAMETERS: n For information pertaining to float identification, sensor arrays, data parameters, and quality control please refer to descriptions within the file headers. Snapshots created after Jan 01, 2017 include estimated total alkalinity and derived carbon parameters for DIC and pCO2 using one of three algorithms (LIAR, MLR, or CANYON). Floats without a pH sensor will not have these additional parameters within their respective data files. See file headers for details. Additionally, files located at the urls listed above will include carbon parameters derived using observed pH and total alkalinity estimated by the LIAR method. n RESOLUTION: n This archive contains either low resolution or high resolution data. The format is defined by the folder name: SOCCOM_LoResQC_ddmmmyyy or SOCCOM_HiResQC_ddmmmyyyy. Note that for APEX floats, the low resolution files only report data at depths where biogeochemical sensors sample, while the high resolution files merge this low resolution data with higher resolution pressure, temperature and salinity data which is sampled every two meters in the upper 1000 meters. For NAVIS floats all biogeochemical sensors except nitrate are sampled every 2 meters in the upper 1000 m. For NAVIS floats all data is contained in the LoResQC files (no HiResQC files exist). DISCLAIMER: n These data are provided as-is. We do our best to provide high-quality, complete data but make no guarantees as to the presence of errors within the data themselves or the algorithms used in the generation of derived parameters. It is the users responsibility to ensure that the data meets the users needs. However, please report any observed discrepancies in the data to the contact listed below and we will do our best to fix them. CONTACT: n Please report any discrepancies, problems or concerns to the following and include FLOATVIZ SNAPSHOT PROCESSING in the subject line of the email. n Tanya Maurer tmaurer@mbari.org n Josh Plant jplant@mbari.org n SOCCOM Data Management n MBARI n 7700 Sandholdt Road n Moss Landing, CA 95039

Mode and Intermediate Waters in Earth System Models

This report describes work done as part of a joint Princeton-Johns Hopkins project to look at the impact of mode and intermediate waters in Earth System Models. The Johns Hopkins portion of this work focussed on the role of lateral mixing in ventilating such waters, with important implications for hypoxia, the uptake of anthropogenic carbon, the dynamics of El Nino and carbon pumps. The Johns Hopkins group also collaborated with the Princeton Group to help develop a watermass diagnostics framework.

Collaborative Project. Mode and Intermediate Waters in Earth System Models

The focus of this grant was on diagnosing the physical mechanisms controlling upper ocean water mass formation and carbon distribution in Earth System Models (ESMs), with the goal of improving the physics that controls their formation.

Carbon sequestration by patch fertilization: A comprehensive assessment using coupled physical-ecological-biogeochemical models: FINAL REPORT of grant Grant No. DE-FG02-04ER63726

This final report summarizes research undertaken collaboratively between Princeton University, the NOAA Geophysical Fluid Dynamics Laboratory on the Princeton University campus, the State University of New York at Stony Brook, and the University of California, Los Angeles between September 1, 2000, and November 30, 2006, to do fundamental research on ocean iron fertilization as a means to enhance the net oceanic uptake of CO2 from the atmosphere. The approach we proposed was to develop and apply a suite of coupled physical-ecologicalbiogeochemical models in order to (i) determine to what extent enhanced carbon fixation from iron fertilization will lead to an increase in the oceanic uptake of atmospheric CO2 and how long this carbon will remain sequestered (efficiency), and (ii) examine the changes in ocean ecology and natural biogeochemical cycles resulting from iron fertilization (consequences). The award was funded in two separate three-year installments: • September 1, 2000 to November 30, 2003, for a project entitled “Ocean carbon sequestration by fertilization: An integrated biogeochemical assessment.” A final report was submitted for this at the end of 2003 and is included here as Appendix 1. • December 1, 2003 to November 30, 2006, for a follow-on project under the same grant numbermorexa0» entitled “Carbon sequestration by patch fertilization: A comprehensive assessment using coupled physical-ecological-biogeochemical models.” This report focuses primarily on the progress we made during the second period of funding subsequent to the work reported on in Appendix 1. When we began this project, we were thinking almost exclusively in terms of long-term fertilization over large regions of the ocean such as the Southern Ocean, with much of our focus being on how ocean circulation and biogeochemical cycling would interact to control the response to a given fertilization scenario. Our research on these types of scenarios, which was carried out largely during the first three years of our project, led to several major new insights on the interaction between ocean biogeochemistry and circulation. This work, which is described in 2 the following Section II on “Large scale fertilization,” has continued to appear in the literature over the past few years, including two high visibility papers in Nature. Early on in the first three years of our project, it became clear that small patch-scale fertilizations over limited regions of order 100 km diameter were much more likely than large scale fertilization, and we carried out a series of idealized patch fertilization simulations reported on in Gnanadesikan et al. (2003). Based on this paper and other results we had obtained by the end of our first three-year grant, we identified a number of important issues that needed to be addressed in the second three-year period of this grant. Section III on “patch fertilization” discusses the major findings of this phase of our research, which is described in two major manuscripts that will be submitted for publication in the near future. This research makes use of new more realistic ocean ecosystem and iron cycling models than our first paper on this topic. We have several major new insights into what controls the efficiency of iron fertilization in the ocean. Section IV on “model development” summarizes a set of papers describing the progress that we made on improving the ecosystem models we use for our iron fertilization simulations.«xa0less