Small scale terrestrial clay deposits on intertidal sandflats: Behavioral changes and productivity reduction

Wethey, David S.; Hewitt, Judi E.; Thrush, Simon F.

doi:10.1016/j.jembe.2011.12.010

Cited by 22 publications

(20 citation statements)

References 39 publications

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“…Blackburn and Henriksen, 1983;Glud, 2008;Hohaia et al, 2013;Huettel et al, 2003), as well as macrofauna behaviour and ecosystem functioning (e.g. Lohrer et al, 2004;Pratt et al, 2013;Woodin et al, 2012). Benthic macrofauna are known to influence nitrogen cycling (Aller, 1988;Kristensen et al, 1991;Laverock et al, 2011), and the presence of macrophytes and microphytobenthos is also expected to influence pore water nutrient concentrations and the level of experimental enrichment.…”

Section: Introductionmentioning

confidence: 99%

In situ soft sediment nutrient enrichment: A unified approach to eutrophication field experiments

Douglas

Pilditch

Hines

et al. 2016

Marine Pollution Bulletin

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Adding fertiliser to sediments is an established way of studying the effects of eutrophication but a lack of consistent methodology, reporting on enrichment levels, or guidance on application rates precludes rigorous synthesis and meta-analysis. We developed a simple enrichment technique then applied it to 28 sites across an intertidal sandflat. Fertiliser application rates of 150 and 600 g N m −2 resulted in pore water ammonium concentrations respectively 1-110 and 4-580 × ambient, with greater elevations observed in deeper (5-7 cm) than surface (0-2 cm) sediments. These enrichment levels were similar to eutrophic estuaries and were maintained for at least seven weeks. The high between-site variability could be partially explained by the sedimentary environment and macrofaunal community (42%), but only at the high application rate. We suggest future enrichment studies should be conducted in situ across large environmental gradients to incorporate real world complexity and increase generality of conclusions.

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Section: Introductionmentioning

confidence: 99%

In situ soft sediment nutrient enrichment: A unified approach to eutrophication field experiments

Douglas

Pilditch

Hines

et al. 2016

Marine Pollution Bulletin

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“…Nevertheless, both processes influence sediment community composition and functioning. Numerous studies illustrate that terrigenous sediment deposition affects coastal soft-sediment community composition, dynamics, species behavior and ecosystem functioning [6], [7], [8]. Furthermore, suspended sediments decrease the fitness of filter feeding organisms directly by decreasing filtration rate and absorption efficiency that reduces net energy intake [9], and indirectly by increasing turbidity and hence decreasing water column primary production, i.e.…”

Section: Introductionmentioning

confidence: 99%

Conditional Responses of Benthic Communities to Interference from an Intertidal Bivalve

et al. 2013

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Habitat-modifying organisms that impact other organisms and local functioning are important in determining ecosystem resilience. However, it is often unclear how the outcome of interactions performed by key species varies depending on the spatial and temporal disturbance context which makes the prediction of disturbance-driven regime shifts difficult. We investigated the strength and generality of effects of the filter feeding cockle Cerastoderma edule on its ambient intertidal benthic physical and biological environment. By comparing the magnitude of the effect of experimental cockle removal between a non-cohesive and a sheltered cohesive sediment in two different periods of the year, we show that the outcome of cockle interference effects relates to differences in physical disturbance, and to temporal changes in suspended sediment load and ontogenetic changes in organism traits. Interference effects were only present in the cohesive sediments, though the effects varied seasonally. Cockle presence decreased only the density of surface-dwelling species suggesting that interference effects were particularly mediated by bioturbation of the surface sediments. Furthermore, density reductions in the presence of cockles were most pronounced during the season when larvae and juveniles were present, suggesting that these life history stages are most vulnerable to interference competition. We further illustrate that cockles may enhance benthic microalgal biomass, most likely through the reduction of surface-dwelling grazing species, especially in periods with high sediment load and supposedly also high bioturbation rates. Our results emphasize that the physical disturbance of the sediment may obliterate biotic interactions, and that temporal changes in environmental stressors, such as suspended sediments, may affect the outcome of key species interference effects at the local scale. Consequently, natural processes and anthropogenic activities that change bed shear stress and sediment dynamics in coastal soft-sediment systems will affect cockle-mediated influences on ecosystem properties and therefore the resilience of these systems to environmental change.

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“…liliana live at a depth of 2–10 cm in mid-shore sandy sediments and feed on surface MPB using an inhalant siphon [ 26 ]. During feeding, this species creates pore-water pressure gradients that oxygenate deeper sediments and force nutrient rich pore-water upwards towards the sediment surface, thereby potentially facilitating MPB production [ 27 – 29 ]. M .…”

Section: Introductionmentioning

confidence: 99%

Detecting Subtle Shifts in Ecosystem Functioning in a Dynamic Estuarine Environment

et al. 2015

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Identifying the effects of stressors before they impact ecosystem functioning can be challenging in dynamic, heterogeneous ‘real-world’ ecosystems. In aquatic systems, for example, reductions in water clarity can limit the light available for photosynthesis, with knock-on consequences for secondary consumers, though in naturally turbid wave-swept estuaries, detecting the effects of elevated turbidity can be difficult. The objective of this study was to investigate the effects of shading on ecosystem functions mediated by sandflat primary producers (microphytobenthos) and deep-dwelling surface-feeding macrofauna (Macomona liliana; Bivalvia, Veneroida, Tellinidae). Shade cloths (which reduced incident light intensity by ~80%) were deployed on an exposed, intertidal sandflat to experimentally stress the microphytobenthic community associated with the sediment surface. After 13 weeks, sediment properties, macrofauna and fluxes of oxygen and inorganic nutrients across the sediment-water interface were measured. A multivariate metric of ecosystem function (MF) was generated by combining flux-based response variables, and distance-based linear models were used to determine shifts in the drivers of ecosystem function between non-shaded and shaded plots. No significant differences in MF or in the constituent ecosystem function variables were detected between the shaded and non-shaded plots. However, shading reduced the total explained variation in MF (from 64% in non-shaded plots to 15% in shaded plots) and affected the relative influence of M. liliana and other explanatory variables on MF. This suggests that although shade stress may shift the drivers of ecosystem functioning (consistent with earlier investigations of shading effects on sandflat interaction networks), ecosystem functions appear to have a degree of resilience to those changes.

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Small scale terrestrial clay deposits on intertidal sandflats: Behavioral changes and productivity reduction

Cited by 22 publications

References 39 publications

In situ soft sediment nutrient enrichment: A unified approach to eutrophication field experiments

In situ soft sediment nutrient enrichment: A unified approach to eutrophication field experiments

Conditional Responses of Benthic Communities to Interference from an Intertidal Bivalve

Detecting Subtle Shifts in Ecosystem Functioning in a Dynamic Estuarine Environment

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