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OAS accession Detail for 0291496
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Title: Kelp forest mooring DIC, TA, pCO2, and aragonite saturation state estimations inside the kelp canopy (36° 37.297’ N, 121° 54.102’ W.) at Hopkins Marine Station, recorded between June and October 2018 (NCEI Accession 0291496)
Abstract: This dataset contains chemical data collected in the North Pacific Ocean from 2018-06-07 to 2018-10-04. These data include Aragonite Saturation State, Partial pressure of CO2, dissolved inorganic Carbon, and total alkalinity (TA). The instruments used to collect these data include pH Sensor. These data were collected by Kerry J. Nickols of California State University Northridge, Yuichiro Takeshita of Monterey Bay Aquarium Research Institute, David Mucciarone, Heidi Hirsh, Robert B. Dunbar, and Stephen G. Monismith of Stanford University, and Sarah Traiger of United States Geological Survey as part of the "Collaborative Research: RUI: Building a mechanistic understanding of water column chemistry alteration by kelp forests: emerging contributions of foundation species (Kelp forest biogeochemistry)" project. The Biological and Chemical Oceanography Data Management Office (BCO-DMO) submitted these data to NCEI on 2020-10-16.

The following is the text of the dataset description provided by BCO-DMO:

Dataset Description:
These data are published in Hirsh et al., see related publications section.
Date received: 20201016
Start date: 20180607
End date: 20181004
Seanames:
West boundary: -121.902
East boundary: -121.902
North boundary: 36.622
South boundary: 36.622
Observation types:
Instrument types:
Datatypes:
Submitter:
Submitting institution: Biological and Chemical Oceanography Data Management Office
Collecting institutions:
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Number of observations:
Supplementary information: Acquisition Description:
In order to estimate other carbonate parameters from sensor pH data, we require an additional carbonate parameter. To accomplish this, we created a local empirical relationship to estimate total alkalinity (TA) based on discrete samples, and combined this with sensor data to calculate DIC, pCO2, and aragonite saturation state (ΩAr).

TA was estimated using a multiple linear regression (MLR) approach, with temperature (T) and salinity (S) as inputs (Alin et al., 2012; Carter et al., 2018). This approach has been demonstrated to be effective in the open ocean (Carter et al., 2018) and along the California Coast below 50 m depth (Alin et al., 2012). Takeshita et al. (2015) demonstrated that this MLR approach can be extended to nearshore environments and showed TA could be estimated to ± 6 μmol kg-1 (RMSE) inside a kelp forest in Southern California by applying an offset to the equations from Alin et al. (2012).

Here, we fit an equation of the form used in Alin et al. (2012) to the discrete samples (n = 271) collected in the kelp forest, and obtained the following equation:

TA est = alpha 0 + alpha 1 (T - T r ) + alpha 2 (S - S r ) + alpha 3 (T-T r ) x (S - S r )

with a RMSE of ± 7.3 μmol kg-1. T r and S r are the mean temperature and salinity for the deployment. The estimated total alkalinity (TA est ) was combined with sensor pH to estimate DIC, pCO2, and ΩAr using equilibrium constants from Lueker et al. (2000) and CO2SYS (van Heuven et al., 2011). For a range of pH from 7.56 to 8.30 the standard uncertainty for estimated carbonate system parameters was 8.98 to 13.43 μmol kg-1 DIC, 54.22 to 9.42 μatm pCO2, and 0.0501 to 0.223 ΩAr. These uncertainties were calculated using the ‘errors’ function in seacarb (Gattuso et al., 2020, version 3.2.13 - Accessed 6 Mar 2020) with inputs of TAest and measured pH, temperature and salinity over depth inside the kelp forest.
Availability date:
Metadata version: 1
Keydate: 2024-04-21 04:09:16+00
Editdate: 2024-04-21 04:10:39+00