Air‐sea CO2 fluxes in the near‐shore and intertidal zones influenced by the California Current. Issue 10 (2nd October 2013)

• Record Type: Journal Article
• Authors: Reimer, Janet J.; Vargas, Rodrigo; Smith, Stephen V.; Lara‐Lara, Ruben; Gaxiola‐Castro, Gilberto; Martín Hernández‐Ayón, J.; Castro, Angel; Escoto‐Rodriguez, Martin; Martínez‐Osuna, Juan
• Is Part Of: Journal of geophysical research. Volume 118:Issue 10(2013:Oct.)
• Page Start: 4795
• Page End: 4810
• Publication Date: 2013-10-02
• Subjects: Oceanography -- Periodicals; 551.4605
• DOI: 10.1002/jgrc.20319
• Languages: English
• ISSNs: 2169-9275

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>[1] The study of air‐sea CO<sub>2</sub> fluxes (<italic>F</italic>CO<sub>2</sub>) in the coastal region is needed to better understand the processes that influence the direction and magnitude of <italic>F</italic>CO<sub>2</sub> and to constrain the global carbon budget. We implemented a 1 year (January through December 2009) paired study to measure <italic>F</italic>CO<sub>2</sub> in the intertidal zone (the coastline to 1.6 km offshore) and the near‐shore (∼3 km offshore) off the north‐western coast of Baja California (Mexico); a region influenced by year‐round upwelling. <italic>F</italic>CO<sub>2</sub> was determined in the intertidal zone via eddy covariance; while in the near‐shore using mooring buoy sensors then calculated with the bulk method. The near‐shore region was a weak annual net source of CO<sub>2</sub> to the atmosphere (0.043 mol CO<sub>2</sub> m<sup>−2</sup> y<sup>−1</sup>); where 91% of the outgassed <italic>F</italic>CO<sub>2</sub> was contributed during the upwelling season. Sea surface temperature (SST) and Δ<italic>p</italic>CO<sub>2</sub> (from upwelling) showed the strongest relationship with <italic>F</italic>CO<sub>2</sub> in the near‐shore, suggesting the importance of meso‐scale processes (upwelling). <italic>F</italic>CO<sub>2</sub> in the intertidal zone were up to four orders of magnitude higher than <italic>F</italic>CO<sub>2</sub> in the near‐shore. Wind speed showed the strongest relationship with <italic>F</italic>CO<sub>2</sub> in the intertidal zone, suggesting the relevance of micro‐scale processes. Results show that there are substantial spatial and temporal differences in <italic>F</italic>CO<sub>2</sub> between the near‐shore and intertidal zone; likely a result of heterogeneity. We suggest that detailed spatial and temporal measurements are needed across the coastal oceans and continental margins to better understand the mechanisms which control <italic>F</italic>CO<sub>2</sub>, as well as reduce uncertainties and constrain regional and global ocean carbon balances.</p> </abstract>