Seasonal patterns of organic matter stoichiometry along a mountain catchment

DIAZ VILLANUEVA, V; BASTIDAS NAVARRO, M.; ALBARIÑO, R.

HYDROBIOLOGIA

SPRINGER

Lugar: Berlin; Año: 2016

0018-8158

Organic matter (OM) nutrient content isexpected to change as OM is transported fromupstream forested reaches downstream to open land,and these changes could depend on seasonal patterns.The aim of this study was to analyze OM carbonnitrogen and phosphorus content, from headwaterreaches to open reaches downstream. We sampled foursites along a mountain catchment over the course ofone year and quantified fine particulate organic carbon(FPOC) in transport and dissolved organic carbon(DOC) concentration and elemental content. BothFPOC and DOC concentration decreased downstream,and changes in OM stoichiometry depended on theseason. Stoichiometry of FPOM and DOM along thecatchment was similar in autumn, with higher C:P andC:N ratios upstream, which could be associated withthe relative importance of allochthonous versusautochthonous OM origin. Conversely in spring, C:Nwas very low in the forest sites. Our results highlight that headwaters running through pristine forests are asource of POM and DOM for downstream ecosystems,and that the quality of such resources depends onseason.