The region of surface water–groundwater interaction in streams, the hyporheic zone, is important for biogeochemical processes and provides habitat for specialized microbial and invertebrate assemblages. Although hyporheic invertebrates contribute little biomass and respiration relative to microbes in stream sediments, invertebrate effects on biogeochemical processes may be disproportionately large. We tested how various interstitial invertebrate assemblages affected N cycling and respiration in flow-through microcosms filled with alluvial sediment in the laboratory. Average invertebrate biomasses in low and high invertebrate treatments were 0.20 and 19 mg dry mass/L sediment, respectively. Average net NO3− regeneration/uptake rate increased with increasing invertebrate biomass, showing invertebrates suppressed NO3− uptake or stimulated in situ NO3− production. Average respiration (normalized for sediment organic matter) and particulate organic matter (POM) increased 51% and 33%, respectively, with increasing invertebrate biomass, suggesting direct contribution to hyporheic metabolism and/or stimulation of microbial activity and an accumulation of POM driven by invertebrates. We suggest that interstitial invertebrates can substantially alter biogeochemical processes in hyporheic zones.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.