Hyporheic Biofilm Particulate Organic Carbon in a Small Lowland Stream (Sitka, Czech Republic): Structure and Distribution

Abstract

Bacterial abundance, biomass and particulate organic carbon (POC) were determined in the hyporheic sediments <1 mm. The fine fraction (< 0.063 mm) and coarse fraction (0.063-1 mm) were analysed separately. The coarse fraction was dominant (95.5%) and its POC content contributed the major proportion (on average 65%) of the total POC (TPOC). The changes in spatial distribution of TPOC were due to the variation in POC in the fine fraction. Bacteria in the fine fraction contributed on average to 62.9% of the total bacterial abundance and to 51.7% of the total bacterial biomass, despite the fact that the fine fraction represented only ~4.5% of the sediment <1 mm. Our results stress the importance of the fine sediment fraction for bacteria as well as for spatio-temporal distribution of biofilm POC.

Variability of heterotrophic metabolism in small stream corridors of an early successional watershed

“…Heterotrophic metabolic activity in ecosystems can be assessed by measuring community respiration as an integrative process that reflects oxygen‐dependent metabolism and, in aerobic environments, accounts for the bulk of CO 2 flux to the atmosphere [ Young et al , 2008; Martin and Bolstad , 2009]. Quantity and quality of organic matter, temperature, nutrient availability, redox potential and the physical structure of soils and sediments are all important factors influencing rates of respiration in soils and sediments [e.g., Hedin , 1990; Koutný and Rulík , 2007; Arevalo et al , 2010; Bond‐Lamberty and Thomson , 2010]. However, the main driver is often water availability, especially in arid and semiarid climates [ Noy‐Meir , 1973; Belnap et al , 2005] where occasional precipitation events create pulses of metabolic activity in soils and sediments of ephemeral stream channels [ Sala and Lauenroth , 1982; Belnap et al , 2005; Sponseller , 2007].…”

Longitudinal transformation of nitrogen and carbon in the hyporheic zone of an N-rich stream: A combined modelling and field study

“…The low value in the present study could be attributed to the refractory nature of particular organic matter, and to the relatively fine size of the particles in the gravel bars. The smaller the size of the particles, the lower the value of the constant k. Indeed, the smallest fractions are the more processed organic matter, of which the easily biodegradable part is already eliminated (Koutny and Rulik, 2007).…”

Stream Hydrology Controls the Longitudinal Bioreactive Footprint of Urban-Sourced Fine Particles

“…, <100 μm) can pass through the filters and discharge into receiving streams. Bacteria preferentially attach to the finer fraction of particles, and total bacterial abundance and biomass are highest in the finest sediment fraction (<63 μm), despite being a small percentage of the total sediment . Furthermore, the fraction of fine particulate organic matter (FPOM, size <1 mm) serves as an important source of energy and nutrition to in-stream biota because it has a high surface area-to-volume ratio that promotes microbial colonization and subsequent mineralization, decomposition of OM, nutrient cycling, and formation of new biomass. − As human populations tend to concentrate in urban areas worldwide, effects of urban development on fluvial networks can become more commonly prevalent within catchments.…”