Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Related Publications
• Parameters
• Instruments
• Deployments
• Project Information
• Funding

All 7Be data pertaining to upwelling velocity calculations. Measurements were made at the San Pedro Ocean Time-series (SPOT) station (33 33'N, 118 24'W). Data are also published in Table B1 in the following publication:
Haskell, W. Z., et al. 2016. An organic carbon budget for coastal Southern California determined by estimates of vertical nutrient flux, net community production and export. Deep-Sea Research I, 116, 49-76. doi:10.1016/j.dsr.2016.07.003

See complete methodology in Haskell et al. (2016). In summary:
This study is part of an effort aimed at characterizing the biological response to upwelling at SPOT on 21 cruises between January 2013 and June 2014; the Upwelling Regime In-Situ Ecosystem Efficiency (Up.R.I.S.E.E.) study.

Beryllium-7: All methods used in measuring the activity of 7Be and calculating the upwelling velocities presented here are described in Haskell et al. (2015), with three notable exceptions:
1) Due to the continued drought in Southern California, the wet depositional flux of 7Be approached zero toward the end of the 2014 sampling season. Following the logic that the reloading of 7Be associated with aerosols in the atmosphere following each rain event is a function of time between rainfall events (eq. 3c in Haskell et al. (2015)), we increased the maximum reloading rate (rmax) in this equation from 120 to 140 dpm m-2 d-1 for the late May and June 2014 sampling intervals (The wet input flux during this period was ~4% of wet input during this same period in 2013).
2) For October 2013, the upper limit on the measured concentration of 7Be is used in the calculation of upwelling velocity since the measured concentration was 0 +/- 12 dpm m-3.
3) All rainfall rates used in the wet input flux calculation are mean regional rates using the same stations as described in Haskell et al., (2015) with the exception of December 2013, when only one station (Oceanside, CA) was used. The surface currents were dominated by flow from the south prior to the sampling date, according to the JPL Regional Ocean Model (ROMS) output (NASA, 2013). Just as in Haskell et al., (2015), the wet input flux was calculated using the activity measured closest to each rainfall event, until the second half of the spring season (Up18–21) when the seasonal mean was used since there were no measurements of 7Be activity in rain during this period.

BCO-DMO Processing:
-modified parameter names to conform with BCO-DMO naming conventions;
-formatted date to yyyy-mm-dd;
-replaced "-" and blanks (missing data) with "nd";
-added site name, lat, and lon from information on metadata form.

The marine biological pump is one of the primary pathways via which anthropogenic carbon dioxide may be sequestered from the atmosphere and exported to the deep ocean as organic carbon. While the link between nutrient supply and high primary productivity in upwelling regions is well established, factors controlling the organic carbon export efficiency of upwelling ecosystems are not well known. Scientists from the University of Southern California and Pomona College plan to determine the factors that control the rates and magnitudes of two components of biological production, Net Community Production (NCP) and Gross Primary Production (GPP), as well as particulate organic carbon export efficiency, at the San Pedro Ocean Time Series, a coastal site in the California Borderland during periods of minimal and high upwelling velocity over a 2-year span. At this site, past and ongoing observations of hydrography and carbon rain will provide an historical context for interpreting results and mechanisms at work.

Rates of NCP and GPP will be quantified at different upwelling intensity, using dissolved oxygen to argon (O2/Ar) ratios and the oxygen triple isotope composition of dissolved oxygen (O2). The export of organic carbon will be established using 234Th (thorium) profiles in the water column, coupled with floating sediment trap deployments, and the development of a carbon isotope balance for the water column. Upwelling will be characterized using non-steady state budgets for atmospheric 7Be (beryllium) input and its depth-integrated decay, as well as estimating rates based on remote measurements of wind stress curl and budgets for dissolved inorganic carbon and silicon. Application of the O2/Ar ratio and the oxygen triple isotope approach will require depth-integrated profiles of these tracers to evaluate the impact of upwelling on mixed layer inputs and use of non-steady state models during seasonal transitions in upwelling. The comprehensive data set to be obtained should provide insights into the organic carbon export efficiency under variable upwelling regimes and help to relate the satellite-based measurements of chlorophyll to the organic carbon export of these highly productive ecosystems.

Broader Impacts: One graduate and one undergraduate student from the University of Southern California and two undergraduate students from Pomona College would be supported and trained as part of this project.