Benthic-pelagic exchange of microalgae at a tidal flat. 2. Taxonomic analysis

Lucas, Cathy H.; Banham, Clare; Holligan, Patrick M.

doi:10.3354/meps212039

Cited by 63 publications

(41 citation statements)

References 38 publications

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“…Coscinodiscus spp.) compared to the benthic diatoms, the contribution of benthic diatoms to the total diatom carbon in the water column was <1% in June, but up to 25% in late August (Lucas et al 2001). The ecological consequences of these large differences in cell size and the resultant small contribution of benthic diatoms to the total diatom carbon in June have been clearly demonstrated in field studies using stable isotopes as trophic tracers .…”

Section: Resuspension Of Microphytobenthosmentioning

confidence: 86%

“…In addition, there was a major resuspension of some larger phytoplanktonic species, such as the centric diatom Coscinodiscus spp. (~200 µm), which sink to the bed at low current velocities (Lucas et al 2001). At Site 4 (edge), the resuspension of both SPM and chlorophyll a was greater than at Site 2 (central) due to the lower stability of the underlying bed.…”

Section: Resuspension Of Microphytobenthosmentioning

confidence: 99%

“…The temporal variation in microphytobenthic resuspension will occur (1) as a function of changes in current velocity during diurnal tidal cycles and the springneap cycle, (2) over seasonal cycles (due to variation in sediment stability, microphytobenthic growth and intermittent storms, and (3) in response to interannual variation (largely due to climatically driven changes in the biological cycles of benthic diatoms and grazers; Widdows et al 2000b). The nature or quality of the resuspended benthic algae varied spatially, ranging from epipsammic diatoms attached to sand grains (Sites 4 and 5) to epipelic diatoms (such as the genera Navicula and Nitzschia) which tend to form dense algal mats on silty sediments (Sites 2 and 3) (Lucas et al 2001). …”

Section: Resuspension Of Microphytobenthosmentioning

confidence: 99%

“…Peaks in chlorophyll a, its degradation products (phaeopigments) and SPM occurred in the water column above the bed, and were associated with resuspended benthic diatoms (primarily Navicula spp.) and large numbers of diatom frustules (Lucas et al 2001). In addition, there was a major resuspension of some larger phytoplanktonic species, such as the centric diatom Coscinodiscus spp.…”

Section: Resuspension Of Microphytobenthosmentioning

confidence: 99%

“…• seasonal variations in sediment properties and benthic community structure ); • modelling of sediment dynamics (fine silt) as a function of tidal currents (Baptist et al 1999); • the impact of currents, macrobenthos and microphytobenthos on sediment erosion and deposition processes (Widdows et al 2000a, Lucas et al 2003); • tidal variations in resuspension of microphytobenthos (Lucas et al , 2001); • vertical mixing of sediment estimated by tracer experiments .…”

Section: Introductionmentioning

confidence: 99%

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Role of physical and biological processes in sediment dynamics of a tidal flat in Westerschelde Estuary, SW Netherlands

Widdows

Blauw²,

Heip

et al. 2004

Mar. Ecol. Prog. Ser.

Self Cite

110

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This article synthesises a series of studies concerned with physical, chemical and biological processes involved in sediment dynamics (sedimentation, erosion and mixing) of the Molenplaat tidal flat in the Westerschelde (SW Netherlands). Total sediment accretion rate on the flat (sand to muddy sand) was estimated to be ~2 cm yr -1 , based on 210 Pb and 137 Cs profiles. 7 Be showed maximum activity in the surface sediments during summer, reflecting accretion of fine silt at this time of year, and total vertical mixing of sediment to be in the order of 50 cm 2 yr -1 . The extent to which different physical and biological processes (tidal currents, air exposure, bio-stabilisation, biodeposition and bioturbation) contributed towards sediment dynamics was estimated. A sediment transport model based on physical factors estimated sedimentation rates of 1.2 cm yr -1 , but did not account for tidal or seasonal variation in suspended particulate matter (SPM), wind or effects of spring-neap tidal cycles. When the model was run with an increased critical bed shear stress due to the microphytobenthos, net sedimentation rates increased 2-fold. These higher rates were in closer agreement with the rates derived from the depth profiles of radionuclides for the central region of the tidal flat (2.0 to 2.4 cm yr -1 ). Therefore a significant part of the sedimentation rate (~50%) may be explained by spatial-temporal changes in biological processes, including 'bio-stabilisation' by microphytobenthos, together with the enhanced biodeposition of silt by suspension feeders, and offset by processes of 'bio-destabilisation' by grazers and bioturbators. In the centre of the tidal flat there was a shift from high sediment stability in spring-summer 1996 to low sediment stability in autumn 1997, quantified by a significant reduction in critical erosion velocity of 0.12 to 0.15 m s -1 , and accompanied by a 30-to 50-fold increase in sediment erosion rate. The change was associated with a shift from a tidal flat dominated by benthic diatoms and a low biomass of bioturbating clams (Macoma balthica), to a more erodable sediment with a lower microphytobenthos density and a higher biomass of M. balthica. Vertical mixing of sediment and organic matter, studied using a variety of tracers, was rapid and enhanced by advective water flow at sandy sites and by burrowing polychaetes and bivalves at silty sites. The sediment dynamics and biogeochemistry of tidal flats is dependent on the complex interactions between physical, chemical and biological processes/properties, which include tidal currents, river flows, storm waves, air exposure, dehydration in summer, ice-scour in winter, sediment properties (grain size and composition, organic content, nutrient content, redox balance), stabilisation by biota (algal biofilms, mussel beds, salt marsh) and destabilisation by biota (bioturbating bivalves, scouring around clumps of animals and plants). To date, there have been very few multi-disciplinary studies providing an integrated view of the sedim...

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Section: Resuspension Of Microphytobenthosmentioning

confidence: 86%

Section: Resuspension Of Microphytobenthosmentioning

confidence: 99%

Section: Resuspension Of Microphytobenthosmentioning

confidence: 99%

Section: Resuspension Of Microphytobenthosmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Role of physical and biological processes in sediment dynamics of a tidal flat in Westerschelde Estuary, SW Netherlands

Widdows

Blauw²,

Heip

et al. 2004

Mar. Ecol. Prog. Ser.

Self Cite

110

View full text Add to dashboard Cite

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Effects of diatoms on erosion and accretion processes in saltmarsh inferred from field observations of hydrodynamic and sedimentary processes

Chen

Zhang³

et al. 2020

Ecohydrology

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Microphytobenthos influence sediment dynamics via their growth and covering on the surface sediment of saltmarshes. To understand the sediment transport and morphological changes resulting from microphytobenthos in a saltmarsh, two parallelly located sites were established to measure the hydrodynamic forces, sediment characteristics and microphytobenthos properties both in winter and summer. Diatoms were not observed at any of the two sites in winter because of their growth cycles. In summer, however, diatoms were found in both sites, with a chlorophyll a (Chl-a) concentration of 4.1 μg/g in the surficial sediment at the unvegetated site and a Chl-a concentration of 1.4 μg/g at the vegetated site. Interactions between diatoms and fine particle accumulation induced positive feedbacks between the seabed stable states and the growth of diatoms. Furthermore, the critical erosion threshold value in the vegetated area was 0.33 N/m 2 , whereas the value in the adjacent unvegetated area reached up to 0.43 N/m 2 because of the dense diatom armouring in summer, which increased 50% and 126% critical erosion threshold values than those at the corresponding sites in winter. Consequently, net sediment accumulation occurred in the unvegetated area in summer but opposite to that in winter. These results reveal that high coverage of diatoms contributes to substantial impacts on bed erodibility and sedimentary processes, which is vital for the understanding of the morphological evolution in saltmarshes, and provide valuable suggestions for coastal saltmarsh reconstruction.

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Benthic primary producers are key to sustain the Wadden Sea food web: stable carbon isotope analysis at landscape scale

Christianen

Middelburg

Holthuijsen

et al. 2017

Ecology

131

121

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Abstract. Coastal food webs can be supported by local benthic or pelagic primary producers and by the import of organic matter. Distinguishing between these energy sources is essential for our understanding of ecosystem functioning. However, the relative contribution of these components to the food web at the landscape scale is often unclear, as many studies lack good taxonomic and spatial resolution across large areas. Here, using stable carbon isotopes, we report on the primary carbon sources for consumers and their spatial variability across one of the world's largest intertidal ecosystems (Dutch Wadden Sea; 1460 km 2 intertidal surface area), at an exceptionally high taxonomic (178 species) and spatial resolution (9,165 samples from 839 locations). The absence of overlap in d13 C values between consumers and terrestrial organic matter suggests that benthic and pelagic producers dominate carbon input into this food web. In combination with the consistent enrichment of benthic primary producers (d 13 C À16.3&) relative to pelagic primary producers (d 13 C À18.8) across the landscape, this allowed the use of a two-food-source isotope-mixing model. This spatially resolved modelling revealed that benthic primary producers (microphytobenthos) are the most important energy source for the majority of consumers at higher trophic levels (worms, molluscs, crustaceans, fish, and birds), and thus to the whole food web. In addition, we found large spatial heterogeneity in the d13 C values of benthic primary producers (d 13 C À19.2 to À11.5&) and primary consumers (d 13 C À25.5 to À9.9&), emphasizing the need for spatially explicit sampling of benthic and pelagic primary producers in coastal ecosystems. Our findings have important implications for our understanding of the functioning of ecological networks and for the management of coastal ecosystems.

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Benthic-pelagic exchange of microalgae at a tidal flat. 2. Taxonomic analysis

Cited by 63 publications

References 38 publications

Role of physical and biological processes in sediment dynamics of a tidal flat in Westerschelde Estuary, SW Netherlands

Role of physical and biological processes in sediment dynamics of a tidal flat in Westerschelde Estuary, SW Netherlands

Effects of diatoms on erosion and accretion processes in saltmarsh inferred from field observations of hydrodynamic and sedimentary processes

Benthic primary producers are key to sustain the Wadden Sea food web: stable carbon isotope analysis at landscape scale

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