author = "Val{\'e}rio, Aline de Matos and Kampel, Milton and Vantrepotte, 
                         Vincent and Ward, Nicholas D. and Sawakuchi, Henrique Oliveira and 
                         Less, Diani Fernanda da Silva and Neu, Vania and Cunha, Alan and 
                         Richey, Jeffrey",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)}",
                title = "Using CDOM optical properties for estimating DOC concentrations 
                         and pCO2 in the Lower Amazon River",
              journal = "Optics Express",
                 year = "2018",
               volume = "26",
               number = "4",
                pages = "A657--A677",
                month = "July",
             abstract = "Coloured dissolved organic matter (CDOM) is one of the major 
                         contributors to the absorption budget of most freshwaters and can 
                         be used as a proxy to assess non-optical carbon fractions such as 
                         dissolved organic carbon (DOC) and the partial pressure of carbon 
                         dioxide (pCO2). Nevertheless, riverine studies that explore the 
                         former relationships are still relatively scarce, especially 
                         within tropical regions. Here we document the spatial-seasonal 
                         variability of CDOM, DOC and pCO2, and assess the potential of 
                         CDOM absorption coefficient (aCDOM(412)) for estimating DOC 
                         concentration and pCO2 along the Lower Amazon River. Our results 
                         revealed differences in the dissolved organic matter (DOM) quality 
                         between clearwater (CW) tributaries and the Amazon River 
                         mainstream. A linear relationship between DOC and CDOM was 
                         observed when tributaries and mainstream are evaluated separately 
                         (Amazon River: N = 42, R2 = 0.74, p<0.05; CW: N = 13, R2 = 0.57, 
                         p<0.05). However, this linear relationship was not observed during 
                         periods of higher rainfall and river discharge, requiring a 
                         specific model for these time periods to be developed (N = 25, R2 
                         = 0.58, p<0.05). A strong linear positive relation was found 
                         between aCDOM(412) and pCO2(N = 69, R2 = 0.65, p<0.05) along the 
                         lower river. pCO2 was less affected by the optical difference 
                         between tributaries and mainstream waters or by the discharge 
                         conditions when compared to CDOM to DOC relationships. Including 
                         the river water temperature in the model improves our ability to 
                         estimate pCO2 (N = 69; R2 = 0.80, p<0.05). The ability to assess 
                         both DOC and pCO2 from CDOM optical properties opens further 
                         perspectives on the use of ocean colour remote sensing data for 
                         monitoring carbon dynamics in large running water systems 
                  doi = "10.1364/OE.26.00A657",
                  url = "http://dx.doi.org/10.1364/OE.26.00A657",
                 issn = "1094-4087",
             language = "en",
           targetfile = "valerio_using.pdf",
        urlaccessdate = "14 abr. 2021"