Response of biofilm-dwelling nematodes to habitat changes in the Garonne River, France: influence of hydrodynamics and microalgal availability

Majdi, Nabil; Traunspurger, Walter; Boyer, Stéphane; Mialet, Benoît; Tackx, M.; Fernández, R. Hernández; Gehner, Stefanie; Ten-Hage, Loı̈c; Buffan‐Dubau, Evelyne

doi:10.1007/s10750-011-0781-6

Cited by 45 publications

(53 citation statements)

References 58 publications

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“…At a low velocity, insufficient nutrient acquisition (owing to the limited diffusional influx) could lead to decreased Chl-a biomass. In contrast, high near-bed water velocity increases shear stress, which can lead to sloughing of the biomass (i.e., the detachment of biomass sections caused by the death of cells at the biomass/solid interface) [49]. Thus, biomass accumulation may require a The positive effect of near-bed velocity persists until the saturation of nutrient uptake occurs [47,48].…”

Section: Effect Of Velocity On Chlorophyll-amentioning

confidence: 99%

Nonlinear Relationship of Near-Bed Velocity and Growth of Riverbed Periphyton

Ateia

Nasr

Ikeda

et al. 2016

Water

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Artificial streams were set up to test the relationship between near-bed water velocity and periphyton growth. Periphyton community samples collected from a Japanese stream were incubated for 44 days under a light intensity of 252 ± 72 µmol·photons/m 2 ·s, a temperature of 20-25 • C, and three near-bed water velocity classes: low (<17.9 cm/s), moderate (17.9-32.8 cm/s), and high (>32.8 cm/s). A logistic model was applied to estimate the maximum net growth rate (µ max ) and carrying capacity (B max ). A response surface method was also applied to estimate chlorophyll a (Chl-a) and ash-free dry mass (AFDM) with respect to the independent variables (i.e., time and water velocity). We detected both the highest µ max (1.99 d −1 ) and highest B max (7.01 mg/m 2 ) for Chl-a at the moderate water velocity. For AFDM, we observed the highest µ max (0.57 d −1 ) and B max (1.47 g/m 2 ) at the low and moderate velocity classes, respectively. The total algae density in the region of moderate velocity at the end of the experiment was 6.47 × 10 3 cells/cm 2 , corresponding to levels 1.7 and 1.3 times higher than those at lower and higher velocities, respectively. Our findings indicated that the moderate near-bed water velocity provided favorable conditions for algal growth and corresponding biomass accumulation.

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Section: Effect Of Velocity On Chlorophyll-amentioning

confidence: 99%

Nonlinear Relationship of Near-Bed Velocity and Growth of Riverbed Periphyton

Ateia

Nasr

Ikeda

et al. 2016

Water

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“…The mobile phase was set after Barlow et al (1997). Microphytic pigments were determined and quantified by comparing their retention time and absorption spectra with those of reference pure standards (DHI LAB products; see Majdi et al 2011 for further details). Biofilm and pelagic phytopigment concentrations were both expressed per surface units (e.g.…”

Section: Phytopigment Analysismentioning

confidence: 99%

“…Emphasis was placed on diatoms since they dominate the biofilm microphytobenthic community in the middle course of the Garonne River (Leflaive et al 2008, Majdi et al 2011. We specifically aimed to (1) determine whether biofilm export to the water column was continuous or whether it mainly occurred after floods and (2) determine the key environmental factors influencing benthic− pelagic coupling and diatom community structure and similarity between benthic and pelagic communities.…”

Section: Introductionmentioning

confidence: 99%

“…1; longitude: 43°23' 45'' N; latitude: 01°17' 53'' E; elevation: 175 m above sea level [a.s.l.]). The epilithic microbial and invertebrate communities at this site are described elsewhere (Lyautey et al 2005b, Leflaive et al 2008, Majdi et al 2011, 2012a). …”

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confidence: 99%

“…These suspensions were divided into 3 groups of 4 replicates to be used for meiofaunal counts, algal pigment analyses and estimation of epilithic ash-free dry mass (AFDM). The procedures are detailed in Majdi et al (2011Majdi et al ( , 2012a.One large cobble (mean diameter = 30 cm) was additionally collected from October 2008 to March 2010 (n = 19), and the biofilm was scraped off from its entire upper surface with a scalpel and toothbrush. This biofilm sample was preserved with formaldehyde (final concentration = 4%) for the identification of benthic (biofilm) diatoms.…”

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Contribution of epilithic diatoms to benthic-pelagic coupling in a temperate river

Tekwani¹,

Majdi²,

Mialet³

et al. 2013

Aquat. Microb. Ecol.

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Water residence time in the middle course of rivers is often too short to allow substantial phytoplankton development, and primary production is essentially provided by benthic phototrophic biofilms. However, cells occurring in the water column might derive from biofilm microalgae, and, reciprocally, sedimenting microalgae could represent a continuous source of colonizers for benthic biofilms. A comparative study of biofilm and pelagic microphytic communities (with special focus on diatoms) was carried out over 15 mo in the Garonne River, France. Diatoms dominated both biofilm and pelagic microphytic communities. Typically benthic diatoms were found in high abundance in the water column, and their biomass in the water was correlated with their biomass in the biofilm, indicating the benthic origin of these cells. Variations in river discharge and temperature drove the temporal distribution of benthic and pelagic communities: under high flow mixing (winter) communities showed the greatest similarity, and during low flow (summer) they differed the most. Even during low flow, typical benthic species were observed in the water column, indicating that benthic−pelagic exchanges were not exclusively due to high water flow. Moreover, during low flow periods, planktonic diatoms typically settled within biofilms, presumably because of higher water residence times, and/or upstream reservoir flushing.KEY WORDS: Periphyton · Distribution · Biofilm · Microphytobenthos · Phytoplankton · Algal ecology · Community structure · HPLC Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 69: [47][48][49][50][51][52][53][54][55][56][57] 2013 Benthic algae on the river bed are generally associated with heterotrophic microorganisms (bacteria, flagellates and ciliates) embedded in a mucous matrix composed of exopolymeric exudates (EPS) and trapped detritic and mineral particles, to form biofilms (Lock et al. 1984, Romaní et al. 2004. These biofilms are shaped by abiotic and biotic influences (e.g. light, flow, nutrients, grazing, allelopathy) that affect their structure and functions (e.g. Hillebrand 2002, Sabater et al. 2002, Lyautey et al. 2005a, Boulêtreau et al. 2006, Mathieu et al. 2007). The dynamics of epilithic biofilms include a growth phase, corresponding to an ecological succession of microbial colonizers onto the substratum (e.g. Korte & Blinn 1983, Lyautey et al. 2005a, and a detachment phase. Detachment of components of the biofilm can occur either through flow abrasion and/or through self-detachment processes (Biggs & Close 1989, Boulêtreau et al. 2006. Also meio-and macrofauna drilling and grazing the biofilm influence its architecture and growth dynamics (Lawrence et al. 2002, Gaudes et al. 2006, Kathol et al. 2011. In the middle course of fast-moving rivers, cells occurring in the water column are derived essentially from the detachment of phototrophic biofilms (Roeder 1977, Ameziane et al. 2003. Conversely, drifting microalgae could represent a continuous source of...

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The food web perspective on aquatic biofilms

Weitere

Erken

Majdi

et al. 2018

Ecological Monographs

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Biofilms, the complex communities of microbiota that live in association with aquatic interfaces, are considered to be hotspots of microbial life in many aquatic ecosystems. Although the importance of attached algae and bacteria is widely recognized, the role of the highly abundant biofilm‐dwelling micrograzers (i.e., heterotrophic protists and small metazoans) is poorly understood. Studies often highlight the resistance of bacterial biofilms to grazing within the microbial food web and therefore argue that the micrograzers have a modulating role (i.e., have effects on biofilm phenotype) rather than a direct trophic role within biofilms. In the present review, we show that this view comes too short, and we establish a conceptual framework of biofilm food webs consisting of three major elements. (1) Energy pathways and subsidization from plankton. As inhabitants of interfaces, biofilm‐dwelling grazers potentially access both planktonic organisms and surface‐associated organisms. They can play an important role in importing planktonic production into the biofilm food web and thus in the coupling of the planktonic and benthic food webs. Nevertheless, specialized grazers are also able to utilize significant amounts of autochthonous biofilm production. (2) Horizontal complexity of the basal food web. While bacteria and algae within biofilms are edible in general, food quality and accessibility of both bacteria and algae can differ considerably between different prey phenotypes occurring during biofilm formation with respect to morphology, chemical defense, and nutrient stoichiometry. Instead of considering bacteria and algae within biofilms to be generally resistant to feeding by micrograzers, we suggest considering a horizontal food‐quality axis to be at the base of biofilm food webs. This food quality gradient is probably associated with increasing costs for the micrograzers. (3) Vertical food web complexity and food chain length. In addition to the consumption of bacteria and algae, many predatory micrograzers exist within biofilm food webs. With the help of video microscopy, we were able to demonstrate the existence of a complex food web with several trophic levels within biofilms. Our conceptual framework should assist in integrating food web concepts and processes into whole‐biofilm budgets and in understanding food‐web‐related interactions within biofilms.

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Response of biofilm-dwelling nematodes to habitat changes in the Garonne River, France: influence of hydrodynamics and microalgal availability

Cited by 45 publications

References 58 publications

Nonlinear Relationship of Near-Bed Velocity and Growth of Riverbed Periphyton

Nonlinear Relationship of Near-Bed Velocity and Growth of Riverbed Periphyton

Contribution of epilithic diatoms to benthic-pelagic coupling in a temperate river

The food web perspective on aquatic biofilms

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