DOI: 10.1007/s10533-016-0269-6
Scopus记录号: 2-s2.0-85003952889
论文题名: Influence of catchment land use and seasonality on dissolved organic matter composition and ecosystem metabolism in headwater streams of a Kenyan river
作者: Masese F.O. ; Salcedo-Borda J.S. ; Gettel G.M. ; Irvine K. ; McClain M.E.
刊名: Biogeochemistry
ISSN: 0168-2563
EISSN: 1573-515X
出版年: 2017
卷: 132, 期: 2018-01-02 语种: 英语
英文关键词: Carbon cycling
; DOM composition
; Land use change
; Tropical streams
; Whole-stream metabolism
Scopus关键词: agricultural catchment
; biogeochemistry
; carbon cycle
; catchment
; concentration (composition)
; dissolved organic matter
; headwater
; land use change
; light availability
; metabolism
; molecular analysis
; seasonality
; spatial variation
; Kenya
英文摘要: Headwater streams influence the biogeochemical characteristics of large rivers and play important roles in regional and global carbon budgets. The combined effects of seasonality and land use change on the biogeochemistry of headwater streams, however, are not well understood. In this study we assessed the influence of catchment land use and seasonality on the composition of dissolved organic matter (DOM) and ecosystem metabolism in headwater streams of a Kenyan river. Fifty sites in 34 streams draining a gradient of catchment land use from 100% natural forest to 100% agriculture were sampled to determine temporal and spatial variation in DOM composition. Gross primary production (GPP) and ecosystem respiration (ER) were determined in 10 streams draining primarily forest or agricultural catchments. Absorbance and fluorescence spectrophotometry of DOM reflected notable shifts in composition along the land use gradient and with season. During the dry season, forest streams contained higher molecular weight and terrestrially derived DOM, whereas agricultural streams were dominated by autochthonous production and low molecular weight DOM. During the rainy season, aromaticity and high molecular weight DOM increased in agricultural streams, coinciding with seasonal erosion of soils and inputs of organic matter from farmlands. Most of the streams were heterotrophic. However, GPP and ER were generally greater in agricultural streams, driven by higher dissolved nutrient (mainly TDN) concentrations, light availability (open canopy) and temperature compared with forest streams. There were correlations between freshly and autochthonously produced DOM, GPP and ER during both the dry and wet seasons. This is one of the few studies to link land-use with organic carbon dynamics and DOM composition. Measures of ecosystem metabolism in these streams help to affirm the role of tropical streams and rivers as important components of the global carbon cycle and demonstrate that even semi-intensive, smallholder agriculture can have measurable effects on riverine ecosystem functioning. © 2016, Springer International Publishing Switzerland. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/83310
Appears in Collections: 气候减缓与适应 气候变化事实与影响
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作者单位: Department of Fisheries and Aquatic Sciences, University of Eldoret, Eldoret, Kenya; Department of Water Science and Engineering, UNESCO-IHE Institute for Water Education, Delft, Netherlands
Recommended Citation:
Masese F.O.,Salcedo-Borda J.S.,Gettel G.M.,et al. Influence of catchment land use and seasonality on dissolved organic matter composition and ecosystem metabolism in headwater streams of a Kenyan river[J]. Biogeochemistry,2017-01-01,132(2018-01-02)