@Article{ValérioKVWSLNCR:2018:UsCDOp,
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
worldwide.",
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 = "02 maio 2024"
}