A sensor package for mapping pH and oxygen from mobile platforms

Abstract A novel chemical sensor package named “WavepHOx” was developed in order to facilitate measurement of surface ocean pH, dissolved oxygen, and temperature from mobile platforms. The system comprises a Honeywell Durafet pH sensor, Aanderaa optode oxygen sensor, and chloride ion selective electrode, packaged into a hydrodynamic, lightweight housing. The WavepHOx has been deployed on a stand-up paddleboard and a Liquid Robotics Wave Glider in multiple near-shore settings in the Southern California Bight. Integration of the WavepHOx into these mobile platforms has enabled high spatiotemporal resolution pH and dissolved oxygen data collection. It is a particularly valuable tool for mapping shallow, fragile, or densely vegetated ecosystems which cannot be easily accessed by other platforms. Results from three surveys in San Diego, California, are reported. We show pH and dissolved oxygen variability >0.3 and >50% saturation, respectively, over tens to hundreds of meters to highlight the degree of natural spatial variability in these vegetated ecosystems. When deployed during an extensive discrete sampling program, the WavepHOx pH had a root mean squared error of 0.028 relative to pH calculated from fifty six measurements of total alkalinity and dissolved inorganic carbon, confirming its capacity for accurate, high spatiotemporal resolution data collection.

[1]  R. Feely,et al.  Uptake and Storage of Carbon Dioxide in the Ocean: The Global CO2 Survey , 2001 .

[2]  A. Borges.  Do we have enough pieces of the jigsaw to integrate CO2 fluxes in the coastal ocean? , 2005 .

[3]  T. A. DelValls,et al.  The pH of buffers based on 2-amino-2-hydroxymethyl-1,3-propanediol (‘tris’) in synthetic sea water , 1998 .

[4]  J. Smith,et al.  Diel Variability in Seawater pH Relates to Calcification and Benthic Community Structure on Coral Reefs , 2012, PloS one.

[5]  J. Gattuso,et al.  CARBON AND CARBONATE METABOLISM IN COASTAL AQUATIC ECOSYSTEMS , 1998 .

[6]  C. Sweeney,et al.  The observed evolution of oceanic pCO2 and its drivers over the last two decades , 2012 .

[7]  Andrew J. Watson,et al.  Climatological Mean and Decadal Change in Surface Ocean Pco(2), and Net Sea-Air Co2 Flux Over the Global Oceans (Vol 56, Pg 554, 2009) , 2009 .

[8]  Wiley Evans,et al.  pCO2 distributions and air–water CO2 fluxes in the Columbia River estuary , 2013 .

[9]  B. Delille,et al.  Carbon dioxide in European coastal waters , 2006 .

[10]  Adina Paytan,et al.  High-Frequency Dynamics of Ocean pH: A Multi-Ecosystem Comparison , 2011, PloS one.

[11]  D. Gledhill,et al.  Ocean Acidification Refugia of the Florida Reef Tract , 2012, PloS one.

[12]  Gernot E. Friederich,et al.  Applications of in situ pH measurements for inorganic carbon calculations , 2011 .

[13]  Todd R. Martz,et al.  The ocean acidification seascape and its relationship to the performance of calcifying marine invertebrates: Laboratory experiments on the development of urchin larvae framed by environmentally-relevant pCO2/pH , 2011 .

[14]  L. Kapsenberg,et al.  Near-shore Antarctic pH variability has implications for the design of ocean acidification experiments , 2015, Scientific Reports.

[15]  Taro Takahashi,et al.  Atmospheric CO2 uptake by a coastal upwelling system , 2005 .

[16]  A. Dickson,et al.  Technical Note: Controlled experimental aquarium system for multi-stressor investigation of carbonate chemistry, oxygen saturation, and temperature , 2013 .

[17]  Carlos M. Duarte,et al.  A blueprint for blue carbon: toward an improved understanding of the role of vegetated coastal habitats in sequestering CO2 , 2011 .

[18]  Uwe Send,et al.  Dynamic variability of biogeochemical ratios in the Southern California Current System , 2014 .

[19]  Robert H. Byrne,et al.  Spectrophotometric seawater pH measurements: total hydrogen ion concentration scale calibration of m-cresol purple and at-sea results , 1993 .

[20]  Gareth A. Lee,et al.  Controls on pH in surface waters of northwestern European shelf seas , 2014 .

[21]  Ulf Riebesell,et al.  Guide to best practices for ocean acidification research and data reporting , 2011 .

[22]  R. T. Short,et al.  Sensors and Systems for in situ Observations of Marine Carbon Dioxide System Variables , 2010 .

[23]  Todd R. Martz,et al.  Testing the Honeywell Durafet® for seawater pH applications , 2010 .

[24]  H. Paerl,et al.  Air‐water CO2 fluxes in the microtidal Neuse River Estuary, North Carolina , 2012 .

[25]  Jia-Zhong Zhang,et al.  Carbon dynamics of Florida Bay: spatiotemporal patterns and biological control. , 2014, Environmental science & technology.

[26]  C. Sabine,et al.  An autonomous mobile platform for underway surface carbon measurements in open-ocean and coastal waters , 2009, OCEANS 2009.

[27]  Simon J. Ussher,et al.  Iron in the Sargasso Sea (Bermuda Atlantic Time‐series Study region) during summer: Eolian imprint, spatiotemporal variability, and ecological implications , 2005 .

[28]  P. Strutton,et al.  Sea-air CO 2 fluxes in the western Canadian coastal ocean , 2012 .

[29]  Todd R. Martz,et al.  High temporal and spatial variability of dissolved oxygen and pH in a nearshore California kelp forest , 2012 .

[30]  M. DeGrandpre,et al.  Short‐term and seasonal pH,pCO2and saturation state variability in a coral‐reef ecosystem , 2012 .

[31]  G. Laruelle,et al.  Evaluation of sinks and sources of CO2 in the global coastal ocean using a spatially‐explicit typology of estuaries and continental shelves , 2010 .

[32]  Nicholas R. Bates,et al.  A global sea surface carbon observing system: inorganic and organic carbon dynamics in coastal oceans , 2010 .

[33]  Thomas S. Bianchi,et al.  The changing carbon cycle of the coastal ocean , 2013, Nature.

[34]  W. McGillis,et al.  Sea surface pCO2 and carbon export during the Labrador Sea spring-summer bloom: An in situ mass balance approach , 2009 .

[35]  Taro Takahashi,et al.  Climatological distributions of pH, pCO2, total CO2, alkalinity, and CaCO3 saturation in the global surface ocean, and temporal changes at selected locations , 2014 .

[36]  Ulf Riebesell,et al.  BOX 3. GUIDE TO BEST PRACTICES IN OCEAN ACIDIFICATION RESEARCH AND DATA REPORTING , 2009 .

[37]  Ralf Goericke,et al.  Robust empirical relationships for estimating the carbonate system in the southern California Current System and application to CalCOFI hydrographic cruise data (2005–2011) , 2012 .

[38]  Alberto Borges,et al.  Reconciling opposing views on carbon cycling in the coastal ocean: Continental shelves as sinks and near-shore ecosystems as sources of atmospheric CO2 , 2009 .

[39]  Wei-Jun Cai,et al.  Estuarine and coastal ocean carbon paradox: CO2 sinks or sites of terrestrial carbon incineration? , 2011, Annual review of marine science.

[40]  Kenneth S Johnson,et al.  Characterization of an ion sensitive field effect transistor and chloride ion selective electrodes for pH measurements in seawater. , 2014, Analytical chemistry.

[41]  Hartmut Boesch,et al.  Effects of atmospheric light scattering on spectroscopic observations of greenhouse gases from space: Validation of PPDF-based CO_2 retrievals from GOSAT , 2012 .

[42]  Philip J. Bresnahan,et al.  Best practices for autonomous measurement of seawater pH with the Honeywell Durafet , 2014 .

[43]  J. Mathewson,et al.  pH-temperature-nutrient relationships in the eastern tropical Pacific Ocean , 1986 .

[44]  R. Feely,et al.  A new automated underway system for making high precision pCO2 measurements onboard research ships , 1998 .

[45]  Michael D. DeGrandpre,et al.  Aragonite saturation state dynamics in a coastal upwelling zone , 2013 .