Table of Contents

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

This dataset includes chlorophyll a fluorescence and water temperature from gridded in-situ profiles from a Slocum Glider deployed between March and July in 2013 and 2014 in the San Pedro Channel, located in the Southern California Bight off the coast of Los Angeles. 

These data were published in Teel et al., 2018.

In addition to the tabular form of this dataset available by clicking the "Get Data" button on this page, it is also available as a Matlab (*.mat) file containing data matrices and vectors. 
* Note that the tabular dataset has a "DEPTH" parameter, but there is none in the above .mat file.  Each row of the matrices corresponds to 1m depth increments starting with the first row which corresponds to 1m depth to the last row number 80 corresponding to 80m depth.
 

Glider deployment:
For this study, a slocum glider was deployed between March and July in 2013 and 2014 in the San Pedro Channel, located in the Southern California Bight off the coast of Los Angeles. The glider was deployed on a 28 km cross-channel path between Catalina Island and the Palos Verdes Peninsula and completed a single cross-channel pass every 1.5–2 days (average speed 1 km h−1). Data were collected between ∼ 3 and 90 m, with the exception of when the glider crossed the major shipping lanes where the glider was constrained to depths below 20 m to avoid damage or loss from ship traffic.

The GMT time stamp indicates the earliest time stamp for data binned within a single profile.

Glider deployments were from small boats belonging to the USC Wrigley Marine Sciences Center or from the R/V Yellowfin.

Instruments:
Teledyne Webb G1 Slocum electric gliders equipped with a WET Labs EcoPuck FL3 fluorometer (used for Chlorophyll a fluorescence), a WET Labs EcoPuck BB3 sensor (used for backscatter at wavelengths of 532, 660, and 880 nm), and a Sea-Bird flow-through CTD (used for temperature, salinity, and pressure).

For more methodology information see Teel et al., 2018.

Data processing:
Glider data were processed in Matlab (versions R2012b, R2014a, R2015b, and R2016b). The glider data from each 2-day transect were gridded onto an idealized glider transect with 500 m horizontal resolution and 1m vertical resolution that was approximately perpendicular to the mean flow and the coastline. Only glider data within 5 km of the idealized transect were used in this analysis (Fig. 1). Each 500 m bin (N = 62) corresponded approximately with a single downcast and upcast. Only profiles with data for > 85 % of the vertical bins were used for further analyses, thereby excluding partial profiles from under the shipping lanes. The remaining missing data (< 15 % of each profile) were filled using 2-D interpolation from all neighboring bins. A total of 557 profiles from 2013 and 1049 profiles from 2014 were accepted for further analyses.

BCO-DMO Data Manager Processing notes:
* Script to transform originally submitted matlab data matrices and vectors into a tabular dataset attached as a supplemental document to this dataset landing page.
* Tabular version of the data available by pressing the "Get Data" button. NaNs in the matlab data are displayed as "nd" for no data in the BCO-DMO data system.
* Data was rounded in matlab (or else would be 13 decimal places). LAT and LON rounded to 5 decimal places. CHL and TEMP rounded to 3 decimal places.
* ISO_DateTime_UTC (yyyy-mm-ddTHH:MM:SSZ) timestamp with time zone added to the tabular dataset in addition to the matlab datenum column.
* Added depth column to tabular dataset based on submitter's information that each row in the mat file corresponds to 1m depth increments with row 1 starting at 1m.

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.

NSF Award Abstract:
Overview: Anthropogenically induced warming has begun to change the global oceans and has the potential to alter the ocean carbon sink. Future changes in mixed layer depth and the delivery of nutrients into the surface ocean are hypothesized to be the primary processes that will impact primary production and carbon cycling in the ocean. Both of these processes are significantly impacted by submesoscale physical dynamics (1-10 km). However, current global climate models used to understand climate sensitivity do not resolve these important features, and so are missing a fundamental mechanism impacting ocean carbon cycling. In this project, the PI will develop a novel biogeochemical and ecosystem model that captures the impact of submesoscale processes on carbon cycling in a framework that is computationally tractable for large-scale simulations.

The Spatially Heterogeneous Dynamic Plankton (SHiP) model will represent a distribution of resource environments at the subgridscale and will include five phytoplankton functional groups, as well as light, nitrogen, and phosphorus limitation on phytoplankton growth. This research will focus on two oligotrophic sites, the Bermuda Atlantic Time-series Station (BATS) and the Hawaii Ocean Time-series (HOT). The SHiP model will be used to explore the impact of the observed submesoscale dynamics captured by the APEX/ISUS profiling nitrate floats on primary production, species dynamics, and carbon export flux. A suite of model simulations will also be conducted to investigate the sensitivity of carbon cycling at BATS and HOT to changes in the frequency and intensity of submesoscale front formation, such as might occur under future climate scenarios. Finally, the measurement-driven SHiP simulations will be compared against an idealized Regional Ocean Modeling System simulation that explicitly resolves submesoscale dynamics.

Intellectual Merit: Submesoscale processes have been shown to have a significant impact on ocean physics, however, the role that these processes play in carbon cycling remains unknown. This study will provide an observation-based analysis of the impact of submesoscale features on community composition and function in oligotrophic gyres and the sensitivity of this interaction to climatically driven changes. In addition, this work will validate a novel approach for mechanistically incorporating the impact of submesoscale dynamics into coarse-resolution models. This research will provide a computationally tractable framework for exploring the impact of changes in climate on global carbon cycling while including the impact of submesoscale processes.

Broader Impacts: The investigator and students associated with this project will collaborate with the Neighborhood Academic Initiative (NAI) at USC to develop an ocean sciences module including a field trip on an oceanographic research vessel. The NAI strives to improve high school graduation and college matriculation rates in the school district surrounding USC, which serves predominantly Latino/Hispanic and African-American communities. The module will also expose the students to oceanography, and help local high school teachers develop an ocean sciences lesson plan to incorporate into their curriculum.