Dissolved Organic and Inorganic Carbon Flow Paths in an Amazonian Transitional Forest

Neu, Vania; Ward, Nicholas D.; Krusche, Alex V.; Neill, Christopher

doi:10.3389/fmars.2016.00114

Cited by 22 publications

(30 citation statements)

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“…Groundwater reserves have received less attention FIGURE 1 | (1) Atmospheric particles act as cloud-condensing nuclei, promoting cloud formation (Kerminen et al, 2000;Riipinen et al, 2011). (2) Raindrops absorb organic and inorganic carbon through particle scavenging and adsorption of organic vapors while falling toward earth (Waterloo et al, 2006;Neu et al, 2016). (3) Burning and volcanic eruptions produce highly condensed polycyclic aromatic molecules (i.e., black carbon) that is returned to the atmosphere along with greenhouse gases such as CO 2 (Baldock et al, 2004;Myers-Pigg et al, 2016).…”

Section: Hydrologic and Biogeochemical Linkagesmentioning

confidence: 99%

“…Once a raindrop precipitates, the water gains dissolved organic matter (DOM) from these same atmospheric particles and vapors, resulting in DOM concentrations order(s) of magnitude greater than those observed in inland waters and the ocean (Figure 1.2; Artaxo et al, 1988;Waterloo et al, 2006;Germer et al, 2007;Neu et al, 2016). Soils are an important source of OM that is present in atmospheric water vapor.…”

Section: Above-ground Carbon Flow Pathsmentioning

confidence: 99%

“…In the tropical Amazon basin, the flux of DOC in rainfall ranges from 27.5 kg ha −1 year −1 in the Rio Negro, a relatively pristine forested area in the central Amazon (Filoso et al, 1999), to a maximum of 123.4 kg ha −1 year −1 in Paragominas, a heavily deforested area in the eastern Amazon (Markewitz et al, 2004), with the highest rainfall fluxes occurring near transitional regions with significant deforestation and burning (Neu et al, 2016). Considering hydrologic regimes are similar in the above regions, the concentration of DOC in rainfall is the largest factor driving these differences in rainfall DOC fluxes.…”

Section: Above-ground Carbon Flow Pathsmentioning

confidence: 99%

“…Considering hydrologic regimes are similar in the above regions, the concentration of DOC in rainfall is the largest factor driving these differences in rainfall DOC fluxes. Throughfall fluxes are generally the highest of each respective flow path in the tropics, with net fluxes (i.e., not including rainfall DOC) ranging from 68.4 kg ha −1 year −1 (Neu et al, 2016) to 195.1 kg ha −1 year −1 (Germer et al, 2007) in the Amazon, compared to a stem flow flux of 1.5 kg ha −1 year −1 (Neu et al, 2016). The abundance and composition of DOM in these above-ground flowpaths is largely controlled by the type of vegetation/landscape that the water is exposed to and surface properties of plants such as leaf composition, surface texture (i.e., rugosity), and the abundance of epiphytes (Neu et al, 2016).…”

Section: Above-ground Carbon Flow Pathsmentioning

confidence: 99%

“…The distance that water and carbon moves through soils unsaturated with moisture (e.g., the vadose zone) is an important control on groundwater DOM concentrations, with the lowest DOM concentrations being observed in regions with deep vadose zones. DOM concentrations are generally lower in below ground stocks relative to above ground counterparts largely due to the effects of microbial processing (Peter et al, 2012b;Neu et al, 2016). For example, Baker et al (2000) demonstrated that snow-melt was an important source of both DOM and dissolved oxygen to groundwater in a mountainous setting in New Mexico, USA.…”

Section: Below-ground Carbon Flow Pathsmentioning

confidence: 99%

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Where Carbon Goes When Water Flows: Carbon Cycling across the Aquatic Continuum

et al. 2017

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The purpose of this review is to highlight progress in unraveling carbon cycling dynamics across the continuum of landscapes, inland waters, coastal oceans, and the atmosphere. Earth systems are intimately interconnected, yet most biogeochemical studies focus on specific components in isolation. The movement of water drives the carbon cycle, and, as such, inland waters provide a critical intersection between terrestrial and marine biospheres. Inland, estuarine, and coastal waters are well studied in regions near centers of human population in the Northern hemisphere. However, many of the world's large river systems and their marine receiving waters remain poorly characterized, particularly in the tropics, which contribute to a disproportionately large fraction of the transformation of terrestrial organic matter to carbon dioxide, and the Arctic, where positive feedback mechanisms are likely to amplify global climate change. There are large gaps in current coverage of environmental observations along the aquatic continuum. For example, tidally-influenced reaches of major rivers and near-shore coastal regions around river plumes are often left out of carbon budgets due to a combination of methodological constraints and poor data coverage. We suggest that closing these gaps could potentially alter global estimates of CO 2 outgassing from surface waters to the atmosphere by several-fold. Finally, in order to identify and constrain/embrace uncertainties in global carbon budget estimations it is important that we further adopt statistical and modeling approaches that have become well-established in the fields of oceanography and paleoclimatology, for example.

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Section: Hydrologic and Biogeochemical Linkagesmentioning

confidence: 99%

Section: Above-ground Carbon Flow Pathsmentioning

confidence: 99%

Section: Above-ground Carbon Flow Pathsmentioning

confidence: 99%

Section: Above-ground Carbon Flow Pathsmentioning

confidence: 99%

Section: Below-ground Carbon Flow Pathsmentioning

confidence: 99%

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Where Carbon Goes When Water Flows: Carbon Cycling across the Aquatic Continuum

et al. 2017

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Spatial patterns of DOC concentration and DOM optical properties in a Brazilian tropical river‐wetland system

et al. 2017

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The Cerrado (savanna) and Pantanal (wetland) biomes of Central Western Brazil have experienced significant development activity in recent decades, including extensive land cover conversion from natural ecosystems to agriculture and urban expansion. The Cuiabá River transects the Cerrado biome prior to inundating large areas of the Pantanal, creating one of the largest biodiversity hot spots in the world. We measured dissolved organic carbon (DOC) and the optical absorbance and fluorescence properties of dissolved organic matter (DOM) from 40 sampling locations spanning Cerrado and Pantanal biomes during wet and dry seasons. In the upper, more agricultural region of the basin, DOC concentrations were highest in the rainy season with more aromatic and humified DOM. In contrast, DOC concentrations and DOM optical properties were more uniform for the more urbanized middle region of the basin between wet and dry seasons, as well as across sample locations. In the lower region of the basin, wet season connectivity between the river and the Pantanal floodplain led to high DOC concentrations, a fourfold increase in humification index (HIX) (an indicator of DOM humification), and a 50% reduction in the spectral slope (SR). Basin‐wide, wet season values for SR, HIX, and FI (fluorescence index) indicated an increasing representation of terrestrially derived DOM that was more humified. Parallel factor analysis identified two terrestrially derived components (C1 and C2) representing 77% of total fluorescing DOM (fDOM). A third, protein‐like fDOM component increased markedly during the wet season within the more urban‐impacted region.

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