Community structure and seasonal dynamics of diatom biofilms and associated grazers in intertidal mudflats

Sahan, Emel; Sabbe, Koen; Créach, Véronique; Hernandez-Raquet, Guillermina; Vyverman, Wim; Stal, Lucas J.; Muyzer, Gerard

doi:10.3354/ame047253

Cited by 47 publications

(45 citation statements)

References 61 publications

(67 reference statements)

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“…We detected large decreases in diatom abundance and biomass in the presence of grazers, supporting other studies that demonstrated strong grazer impacts on diatom biomass (Hagerthey et al, 2002; Sahan et al, 2007). We also detected decreases in average diatom length in snail addition treatments, suggesting that snails are capable of consuming larger (>25 μm long) diatoms.…”

Section: Discussionsupporting

confidence: 90%

“…Other biotic and abiotic factors, such as salinity (Sahan et al, 2007), sediment grain size (Watermann et al, 1999), or the non-trophic impacts of higher consumers (Armitage and Fong, 2006) can disrupt these interactions and decouple grazing and enrichment effects on benthic microalgal communities. We detected few interactions between snail and nutrient addition treatments, possibly because of high background nutrient levels or strong herbivore pressure.…”

Section: Discussionmentioning

confidence: 99%

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Decoupling of nutrient and grazer impacts on a benthic estuarine diatom assemblage

Armitage

González

Fong

2009

Estuarine, Coastal and Shelf Science

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Strong interactions between top-down (consumptive) and bottom-up (resource supply) trophic factors occur in many aquatic communities, but these forces can act independently in some microphytobenthic communities. Within benthic estuarine diatom assemblages, the dynamics of these interactions and how they vary with abiotic environmental conditions are not well understood. We conducted a field experiment at two sites with varying habitat characteristics to investigate the interactive effects of grazers and nutrients on benthic estuarine diatoms. We crossed snail (Cerithidea californica) and nutrient (nitrogen and phosphorus) addition treatments in enclosures on a restored tidal sandflat and a reference tidal mudflat in Mugu Lagoon, southern California. We repeated the study in summer 2000 and spring 2001 to assess temporal variation in the interactions. Snails caused a large decrease in diatom relative abundance and biomass (estimated as surface area); nutrients increased diatom abundance but did not alter diatom biomass. Snails and nutrients both reduced average diatom length, although the nutrient effect was weaker and temporally variable, occurring in the reference mudflat in the spring. There were few interactions between snail and nutrient addition treatments, suggesting that links between top-down and bottom-up forces on the diatom community were weak. There were no consistent differences in diatom assemblage characteristics between the two study sites, despite marked differences in sediment grain size and other abiotic characteristics between the sites. The strong diatom response to herbivores and weaker responses to enrichment differed from the previous studies where cyanobacteria increased in response to nutrient enrichment, further dissolving the “black box” perception of microphytobenthic communities.

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Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 99%

Decoupling of nutrient and grazer impacts on a benthic estuarine diatom assemblage

Armitage

González

Fong

2009

Estuarine, Coastal and Shelf Science

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“…After the oysters were killed, MPB patches regularly showed a more complex and disaggregated structure instead of the regular patch shape usually observed. Variations in bathymetry, tidal dynamics, sediment type, irradiance and grazing had already been documented as factors structuring MPB spatio-temporal distribution (Brotas et al, 1995;Méléder et al, 2003;Sahan et al, 2007;Ribeiro et al, 2013). However, to date there are only a few studies which have explicitly investigated the influence of nearby macrobenthic communities on MPB dynamics (Dame, 1993;Méléder et al, 2003Newell, 2004;Engel et al, 2017).…”

Section: Oyster Reefs Influence On Mpb Biofilm Developmentmentioning

confidence: 99%

“…Fortunately, the high speed of MPB migration allowed us to work with satellite data that could be obtained during most of the low-tide period. It should also be kept in mind that while MPB biomass at the surface of the sediment can change as a result of vertical migration (Brouwer and Stal, 2001;Chennu et al, 2013), it can also be affected by other exogenous factors such as temperature and irradiance (Saburova and Polikarpov, 2003;Jesus et al, 2009;Coelho et al, 2011). A better understanding of these temporal dynamics requires high spatial and temporal resolution RS data.…”

Section: Rs As a Tool To Investigate Multi-scale Ecological Processesmentioning

confidence: 99%

Satellite remote sensing reveals a positive impact of living oyster reefs on microalgal biofilm development

et al. 2018

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Abstract. Satellite remote sensing (RS) is routinely used for the large-scale monitoring of microphytobenthos (MPB) biomass in intertidal mudflats and has greatly improved our knowledge of MPB spatio-temporal variability and its potential drivers. Processes operating on smaller scales however, such as the impact of benthic macrofauna on MPB development, to date remain underinvestigated. In this study, we analysed the influence of wild Crassostrea gigas oyster reefs on MPB biofilm development using multispectral RS. A 30-year time series combining high-resolution (30 m) Landsat and SPOT data was built in order to explore the relationship between C. gigas reefs and MPB spatial distribution and seasonal dynamics, using the normalized difference vegetation index (NDVI). Emphasis was placed on the analysis of a before-after control-impact (BACI) experiment designed to assess the effect of oyster killing on the surrounding MPB biofilms. Our RS data reveal that the presence of oyster reefs positively affects MPB biofilm development. Analysis of the historical time series first showed the presence of persistent, highly concentrated MPB patches around oyster reefs. This observation was supported by the BACI experiment which showed that killing the oysters (while leaving the physical reef structure, i.e. oyster shells, intact) negatively affected both MPB biofilm biomass and spatial stability around the reef. As such, our results are consistent with the hypothesis of nutrient input as an explanation for the MPB growth-promoting effect of oysters, whereby organic and inorganic matter released through oyster excretion and biodeposition stimulates MPB biomass accumulation.MPB also showed marked seasonal variations in biomass and patch shape, size and degree of aggregation around the oyster reefs. Seasonal variations in biomass, with higher NDVI during spring and autumn, were consistent with those observed on broader scales in other European mudflats. Our study provides the first multi-sensor RS satellite evidence of the promoting and structuring effect of oyster reefs on MPB biofilms.

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“…In undisturbed sediments, microphytobenthos such as diatoms tend to form relatively stable structures like diatom films (Holland et al 1974, Sahan et al 2007), which in turn support a rich and abundant protistan community (Hamels et al 2001, Sahan et al 2007). The permanent reworking of the sediment poses a shear stress, which inhibits the formation of such biofilms.…”

Section: Physical Stressmentioning

confidence: 99%

Effects of the bioturbating lugworm Arenicola marina on the structure of benthic protistan communities

Engel¹,

Behnke²,

Klier³

et al. 2012

Mar. Ecol. Prog. Ser.

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Sedimentary coastal ecosystems like the European Wadden Sea in the northeasternAtlantic harbor large populations of burrowing infauna, such as arenicolide polychaetes. These 'ecosystem engineering' macrofaunal organisms destabilize sediments by reworking and irrigating them, leading to a reorganization of sediment physicochemical state and bacterial communities. Here, we tested the effects of the lugworm Arenicola marina on intertidal psammophilic protistan community diversity and structure in a field experiment. We applied pyrosequencing and community structure analyses to samples in which we manipulated lugworm densities. Irrespective of the presence or absence of the lugworm, protistan abundance and diversity (mostly diatoms and ciliates) was higher in oxic surface sediments compared to anoxic subsurface sediments. In the presence of A. marina, protistan abundances and diversity decreased decisively in surface as well as in subsurface bulk sediment. Also, the protistan community composition differed remarkably, with only 28% of all phylotypes (n total = 855) shared between habitats with and without lugworms. Twenty-seven percent of all taxa were detected exclusively in the presence of lugworms, and 62% of the taxa found in the oxic subsurface sediment surrounding the lugworm burrow were limited to this distinct microenvironment. This suggests that lugworm burrows provide an ecological niche potentially hosting protist taxa that are adapted to fluctuating oxygen supply. We conclude that though the activities of A. marina reduce the overall abundance of protists, they select for very specific and well-adapted taxa. This adds to the overall protistan diversity in intertidal sandflats on larger spatial scales. Most likely, the observed effects of lugworms on protistan community structure and composition are due to a combination of direct trophic and indirect sediment-mediated effects, such as disturbance by reworking the sediment, oxygen supply by burrow ventilation and increased pore water exchange due to bioadvection.

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Community structure and seasonal dynamics of diatom biofilms and associated grazers in intertidal mudflats

Cited by 47 publications

References 61 publications

Decoupling of nutrient and grazer impacts on a benthic estuarine diatom assemblage

Decoupling of nutrient and grazer impacts on a benthic estuarine diatom assemblage

Satellite remote sensing reveals a positive impact of living oyster reefs on microalgal biofilm development

Effects of the bioturbating lugworm Arenicola marina on the structure of benthic protistan communities

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