Transport and degradation of a dinoflagellate bloom in permeable sublittoral sediment

Abstract

Filtration of planktonic algal cells from the water column into permeable sublittoral sediment and the fate of the cells in the shallow sands were studied during a red tide produced by the dinoflagellate Peridinella catenata at Hel Peninsula/Baltic in May 2004. Advective porewater flows associated with ripple topography of the bed caused rapid transport of algal cells down to 5 cm sediment depth. Sedimentary concentrations of algal cells mirrored algal concentrations in the overlying water column with increases and decreases within the upper 3 cm of the bed occurring within a few hours. Sedimentary algal uptake and release significantly differed between stations only 15 m laterally apart. Laboratory sediment-column experiments with 13 C-labeled algal cells revealed algal decomposition at rates of up to 0.2% 13 C h -1 in percolated sands originating from the study site. This was 2 orders of magnitude lower than observed decreases in sediment algal cell C abundance of up to 23% C h -1 after a drop in cell concentrations in the water column. Because bioturbation and ripple migration were negligible, we conclude that advective flushing of the uppermost sediment layer could rapidly remove cells from the sediment. Our results demonstrate close spatial and temporal coupling between algal cell concentrations in the boundary layer and those in the upper 6 cm of permeable sand sediment, and suggest that permeable beds can act as short-term storage buffer for phytoplankton. During passage through the sediment, planktonic algae may benefit from the higher nutrient concentrations available in the porewater. KEY WORDS: Advective transport · Permeable sediment · Phytoplankton bloom · Baltic · Red tide · Peridinella catenata Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 340: [139][140][141][142][143][144][145][146][147][148][149][150][151][152][153] 2007 and calculated filtration rates of up to several hundreds of liters m -2 d -1 . This relatively strong interfacial water flow has the potential to carry suspended small particles into the porous sand bed, and several flume and in situ experiments demonstrated that clay particles, fluorescent tracer particles and planktonic algae can be transported into the bed by the interfacial water flows (Packman & Brooks 1995, Pilditch et al. 1998, Huettel & Rusch 2000, Packman et al. 2000, Packman & Brooks 2001. As oxygen enters the sediment with the same water flows as the particles, and degradation products are removed from the sediment by the porewater flows , this filtration process also promotes a sedimentary environment that is supportive of efficient and rapid degradation of organic particles carried into the bed. According to studies by , Kristensen & Hansen (1995), and Dauwe et al. (2001), the decomposition rate of a large fraction of organic matter buried in marine sands is accelerated by availability of oxygen. Synthesis of the listed findings suggests that shallow permeable shelf beds represent large biocatalytical ...

Temporal variation in the sediment permeability of an intertidal sandflat

“…Algal particles are being transported at least several cm into the sediment at this study site, as found in other studies (e.g. Huettel & Rusch 2000, D'Andrea et al 2002, Huettel et al 2007) as a result of advective transport rather than migration (e.g. diatoms).…”

“…Infaunal feeding behaviour can also work in both ways, maintaining permeability where fine material is consolidated via defecation and pelletisation (Volkenborn et al 2007), but also reducing permeability through the blocking of interstitial spaces by the accumulation of faecal pellets (Brunke & Gonser 1997). Advective processes can transport particulates several cm into the sediment (Huettel & Rusch 2000, Huettel et al 2007). Subsequent physical clogging of sediment is known to reduce permeability (Rehg et al 2005, Volkenborn et al 2007).…”

“…Even small amounts of fine material can have a significant effect: Forster et al (2003) found permeability to be reduced by a factor of 0.6 from ~5 × 10 −12 to ~3 × 10 −12 m 2 after the deposition of a thin layer of fine material (particles <106 µm) in one of very few studies investigating such effects in natural marine sediment cores. Another clogging mechanism, 'bioclogging', also occurs via the transport of allochthonous particulate organic material, such as phytodetritus (Underwood et al 1995, Huettel et al 2007) and mucilage deposition .…”

Characterization of Nitrifying, Denitrifying, and Overall Bacterial Communities in Permeable Marine Sediments of the Northeastern Gulf of Mexico

“…The relative abundance of Alphaproteobacteria phylotypes in particular suggests that this group is well adapted to sediments undergoing continuous and rapid pore water advection as indicated by the high permeability and rapid rates of organic matter turnover that we observed in the sands of the NEGOM. The fact that a predominance of Alphaproteobacteria sequences is also observed in marine bacterioplankton communities (72) may be explained by the recent observations showing enhanced exchange of particles between permeable sediments and the overlying water column (5,18,31,36). In comparison to muddy marine sediments, bacteria could more readily switch between attached and planktonic lifestyles in marine sands.…”

Sandy sediments as active biogeochemical reactors: compound cycling in the fast lane

“…Results from their study suggest that the combination of hydrodynamics and bedform heterogeneity lead to ripple-scale patchiness of organic matter input into coastal shelf sediments, along both the vertical and horizontal directional axes. Conversely, Huettel et al (2007) found that algal decomposition rates in percolated sands were far from explaining the turnover rate of algal cells found in natural bedforms, hence implying that part of the cells are just temporarily retained within the sediment bed.…”