@inbook {5882, title = {Microphytobenthic Biofilms: Composition and Interactions}, booktitle = {Mudflat Ecology}, year = {2018}, pages = {63{\textendash}90}, publisher = {Springer International Publishing}, organization = {Springer International Publishing}, address = {Cham}, abstract = {

Microphytobenthic biofilms in mudflats are characterised by a wide variety of microorganisms and the production of large quantities of extracellular polymeric substances (EPS). In this chapter, the diversity of microphytobenthos (MPB) is reviewed and the complex interactions that take place in mudflat biofilms between microalgae and bacteria are discussed. Microbial interaction in natural biofilms is an emerging field of study in mudflat ecosystems. Although emphasis is placed on EPS and EPS-mediated interactions, because they have received most of the research attention, more direct interactions such as communication and defence are also discussed. Most studies to date have dealt with monospecific or multispecific laboratory biofilms, and environmental studies are still very rare. The development of this field of study in mudflat ecosystems is clearly a major requirement in our understanding of the functioning of mudflat biofilms.

}, isbn = {978-3-319-99194-8}, doi = {10.1007/978-3-319-99194-8_4}, url = {https://doi.org/10.1007/978-3-319-99194-8_4}, author = {C{\'e}dric Hubas and Passarelli, C and Paterson, David M}, editor = {Beninger, Peter G.} } @inbook {5883, title = {Mudflat Ecosystem Engineers and Services}, booktitle = {Mudflat Ecology}, year = {2018}, pages = {243{\textendash}269}, publisher = {Springer International Publishing}, organization = {Springer International Publishing}, address = {Cham}, abstract = {

Ecosystem engineers play a fundamental role in the creation, maintenance and transformation of habitats in tidal flats. Highly diverse in terms of size, phylogeny, and effect on their environment, they can facilitate or hinder a number of organisms, but generally have a positive influence on both the abundance and the diversity of mudflat organisms. The magnitude of the engineering effect is, however, largely dependent on the biotic and abiotic environment of the engineer. In particular, stressful habitats such as mudflats host a large number of ecosystem engineers; understanding interactions between them, and how they vary with abiotic variables, is therefore of crucial importance, to evaluate how ecosystem engineers affect benthic communities and ecosystem functioning. Such understanding will also help human populations which benefit from mudflat organisms and/or functioning (i.e. which derive ecosystem services from them), to maintain and manage the sustainably of tidal flats, in a way which maintains human health and well-being.

}, isbn = {978-3-319-99194-8}, doi = {10.1007/978-3-319-99194-8_10}, url = {https://doi.org/10.1007/978-3-319-99194-8_10}, author = {Passarelli, C and C{\'e}dric Hubas and Paterson, David M}, editor = {Beninger, Peter G.} } @article {4340, title = {The fate of C4 and C3 macrophyte carbon in central Amazon floodplain waters: Insights from a batch experiment}, journal = {Limnologica - Ecology and Management of Inland Waters}, volume = {59}, year = {2016}, pages = {90-98}, abstract = {

The central Amazon floodplains are particularly productive ecosystems, where a large diversity of organic carbon sources are available for aquatic organisms. Despite the fact that C4 macrophytes generally produce larger biomasses than C3 macrophytes, food webs in the central Amazon floodplains appear dominantly based on a C3 carbon source.

In order to investigate the respective fate and degradation patterns of C4 and C3 aquatic plant-derived material in central Amazon floodplains, we developed a 23-days batch experiment. Fatty acid and carbon concentrations as well as stable isotope compositions were monitored over time in 60\ L tanks. These tanks contained Amazon water, with different biomasses of C3 and C4 macrophyte, representative of in situ densities occurring in central Amazon floodplains.

In the C4Paspalum repens treatments, organic (POC, DOC) and inorganic carbon (DIC) got rapidly enriched in 13C, whereas in the C3Salvinia auriculata treatments, POC and DOC showed little change in concentration and isotopic composition, and DIC got depleted in 13C. The contribution of P. repens to POC and DOC was estimated to reach up to 94.2 and 70.7\%, respectively. In contrast, no differences were reported between the C3S. auriculata and control treatments, an observation attributed to the lower C3 biomass encountered in the field, to a slower degradation rate of C3 compared to C4 compounds, and to similar isotopic compositions for river POC and DOC, and C3 compounds.

The 13C enrichments of POC, DOC, and DIC from P. repens treatments were attributed to an enhanced bacterially-mediated hydrolysis and mineralization of C4 material. Evolutions of bacterial abundance and branched fatty acid concentrations confirmed the role of heterotrophic microbial communities in the high P. repens decomposition rate. Our experiment highlights the predominant role of C4 aquatic plants, as a large source of almost entirely biodegradable organic matter available for heterotrophic activity and CO2 outgassing to the atmosphere.

}, keywords = {Central amazon, Degradation, fatty acids, Floodplains, Macrophytes, Stables isotopes}, doi = {doi:10.1016/j.limno.2016.03.008}, author = {Jean-Michel Mortillaro and Passarelli, C and Gwena{\"e}l Abril and C{\'e}dric Hubas and Luis Felipe Artigas and Marc F Benedetti and Najet Thiney and Moreira-Turcq, P and P{\'e}rez, M A and Vidal, L and Tarik Meziane} } @article {3383, title = {Seasonal variations of the composition of microbial biofilms in sandy tidal flats: Focus of fatty acids, pigments and exopolymers}, journal = {Estuarine, Coastal and Shelf Science}, volume = {153}, year = {2015}, pages = {29 - 37}, abstract = {

Abstract Biofilms, or microbial mats, are common associations of microorganisms in tidal flats; they generally consist of a large diversity of organisms embedded in a matrix of Extracellular Polymeric Substances (EPS). These molecules are mainly composed of carbohydrates and proteins, but their detailed monomer compositions and seasonal variations are currently unknown. Yet this composition determines the numerous roles of biofilms in these systems. This study investigated the changes in composition of carbohydrates in intertidal microbial mats over a year to decipher seasonal variations in biofilms and in varying hydrodynamic conditions. This work also aimed to assess how these compositions are related to microbial assemblages. In this context, natural biofilms whose development was influenced or not by artificial structures mimicking polychaete tubes were sampled monthly for over a year in intertidal flats of the Chausey archipelago. Biofilms were compared through the analysis of their fatty acid and pigment contents, and the monosaccharide composition of their \{EPS\} carbohydrates. Carbohydrates from both colloidal and bound \{EPS\} contained mainly glucose and, to a lower extent, galactose and mannose but they showed significant differences in their detailed monosaccharide compositions. These two fractions displayed different seasonal evolution, even if glucose accumulated in both fractions in summer; bound \{EPS\} only were affected by artificial biogenic structures. Sediment composition in fatty acids and pigments showed that microbial communities were dominated by diatoms and heterotrophic bacteria. Their relative proportions, as well as those of other groups like cryptophytes, changed between times and treatments. The changes in \{EPS\} composition were not fully explained by modifications of microbial assemblages but also depended on the processes taking place in sediments and on environmental conditions. These variations of \{EPS\} compositions are likely to alter different ecosystem processes such as biostabilisation or pollutants trapping.

}, keywords = {biofilms, biogenic structures, EPS, fatty acids, monosaccharide composition, pigments}, issn = {0272-7714}, doi = {http://dx.doi.org/10.1016/j.ecss.2014.11.013}, url = {http://www.sciencedirect.com/science/article/pii/S0272771414003412}, author = {Passarelli, C and Tarik Meziane and Najet Thiney and Dominique Boeuf and B Jesus and Mickael Ruivo and Christian Jeanthon and C{\'e}dric Hubas} } @article {Passarelli2013, title = {{Organisms as cooperative ecosystem engineers in intertidal flats}}, journal = {Journal of Sea Research}, volume = {92}, year = {2014}, month = {09/2014}, pages = {92-101}, abstract = {

The importance of facilitative interactions and organismal ecosystem engineering for establishing the structure of communities is increasingly being recognised for many different ecosystems. For example, soft-bottom tidal flats host a wide range of ecosystem engineers, probably because the harsh physico-chemical environmental conditions render these species of particular importance for community structure and function. These environments are therefore interesting when focusing on how ecosystem engineers interact and the consequences of these interactions on community dynamics. In this review, we initially detail the influence on benthic systems of two kinds of ecosystem engineers that are particularly common in tidal flats. Firstly, we examine species providing biogenic structures, which are often the only source of habitat complexity in these environments. Secondly, we focus on species whose activities alter sediment stability, which is a crucial feature structuring the dynamics of communities in tidal flats. The impacts of these engineers on both environment and communities were assessed but in addition the interaction between ecosystem engineers was examined. Habitat cascades occur when one engineer favours the development of another, which in turn creates or modifies and improves habitat for other species. Non-hierarchical interactions have often been shown to display non-additive effects, so that the effects of the association cannot be predicted from the effects of individual organisms. Here we propose the term of {\textquotedblleft}cooperative ecosystem engineering{\textquotedblright} when two species interact in a way which enhances habitat suitability as a result of a combined engineering effect. Finally, we conclude by describing the potential threats for ecosystem engineers in intertidal areas, potential effects on their interactions and their influence on communities and ecosystem function.

}, keywords = {Biogenic Structure, Cooperative Ecosystem Engineers, Habitat Cascade, Sediment stability, tidal flats}, doi = {10.1016/j.seares.2013.07.010}, author = {Passarelli, C and Fr{\'e}d{\'e}ric Olivier and Paterson, D M and Tarik Meziane and C{\'e}dric Hubas} }