期刊
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
卷 121, 期 6, 页码 1522-1539出版社
AMER GEOPHYSICAL UNION
DOI: 10.1002/2016JG003342
关键词
dissolved organic carbon; aquatic; priming; litter leachate; remineralization; reactivity
资金
- NSF DEB [1256724]
- FAPESP [08/58089-9]
- NSF EAR [1528255]
- University of Florida Jon L. and Beverly A. Thompson Endowment
- Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [08/58089-9] Funding Source: FAPESP
- Direct For Biological Sciences
- Division Of Environmental Biology [1256724] Funding Source: National Science Foundation
Here we present direct measurements of the biological breakdown of C-13-labeled substrates to CO2 at seven locations along the lower Amazon River, from bidos to the mouth. Dark incubation experiments were performed at high and low water periods using vanillin, a lignin phenol derived from vascular plants, and at the high water period using four different C-13-labeled plant litter leachates. Leachates derived from oak wood were degraded most slowly with vanillin monomers, macrophyte leaves, macrophyte stems, and whole grass leachates being converted to CO2 1.2, 1.3, 1.7, and 2.3 times faster, respectively, at the upstream boundary, bidos. Relative to bidos, the sum degradation rate of all four leachates was 3.3 and 2.6 times faster in the algae-rich Tapajos and Xingu Rivers, respectively. Likewise, the leachates were broken down 3.2 times more quickly at bidos when algal biomass from the Tapajos River was simultaneously added. Leachate reactivity similarly increased from bidos to the mouth with leachates breaking down 1.7 times more quickly at Almeirim (midway to the mouth) and 2.8 times more quickly across the river mouth. There was no discernible correlation between in situ nutrient levels and remineralization rates, suggesting that priming effects were an important factor controlling reactivity along the continuum. Further, continuous measurements of CO2, O-2, and conductivity along the confluence of the Tapajos and Amazon Rivers and the Xingu and Jaraucu Rivers revealed in situ evidence for enhanced O-2 drawdown and CO2 production along the mixing zone of these confluences.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据