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ABSTRACT Despite the importance of river nutrient retention in regulating downstream water quality and the potential alterations to nutrient fluxes associated with climate-induced changes in Arctic hydrology, current understanding of nutrient cycling in Arctic river systems is limited. This study adopted an experimental approach to quantify conceptual water source contributions (meltwater, groundwater), environmental conditions and uptake of NO3−, NH4+, PO43− and acetate at 12 headwater rivers in Svalbard and so determine the role of changing hydrology on nutrient uptake in these Arctic river systems. Most rivers exhibited low demand for NO3− and PO43−, but demand for NH4+ and acetate was more variable and in several rivers comparable with that measured in sub-Arctic regions. The proportion of meltwater contributing to river flow was not significantly related to nutrient uptake. However, NH4+ uptake was associated positively with algal biomass, water temperature and transient storage area, whereas acetate uptake was associated positively with more stable river channels. Mean demand for NH4+ increased when added with acetate, suggesting NH4+ retention may be facilitated by labile dissolved organic carbon availability in these rivers. Consequently, nutrient export from Arctic river systems could be influenced in future by changes in hydrological and environmental process interactions associated with forecasted climate warming. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The impacts of climate-induced environmental changes on freshwater biodiversity are not well understood in Arctic regions., We quantified water source contributions (meltwater, ground water), environmental habitat conditions and benthic macroinvertebrate community dynamics in north-west Svalbard. The aim was to use contemporary findings to infer how future environmental change may affect these Arctic river ecosystems., Water source dynamics played an important role in influencing environmental habitat conditions; meltwater contributions to flow were related significantly to discharge, channel stability, electrical conductivity and p H., Low regional benthic macroinvertebrate diversity relative to other Arctic regions was attributed to harsh winter conditions and biogeographical dispersal constraints associated with the Svalbard archipelago., Generalised estimating equations and multivariate ordination models showed benthic macroinvertebrate diversity and abundance were influenced significantly by several environmental habitat variables. Rivers in non-glacierised basins typically supported more diverse and abundant communities than those in glacierised basins, most likely as a consequence of the warmer water temperature and less-disturbed habitat conditions associated with these systems., Consequently, shifts in water source contributions driven by changes in climate may alter environmental habitat conditions in Svalbard rivers and could lead to an increase in abundance and diversity among some freshwater macroinvertebrate communities. [ABSTRACT FROM AUTHOR]