The relationship between epilithic biofilm stability and its associated meiofauna under two patterns of flood disturbance

Majdi, Nabil; Mialet, Benoît; Boyer, Stéphane; Tackx, M.; Leflaive, Joséphine; Boulêtreau, Stéphanie; Ten-Hage, Loı̈c; Julien, Frédéric; Fernández, R. Hernández; Buffan‐Dubau, Evelyne

doi:10.1899/11-073.1

Cited by 43 publications

(50 citation statements)

References 75 publications

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“…These two main biological components are respectively mainly algae and cyanobacteria on one side, and bacteria and fungi on the other (Figure 2). Micro-and meiofauna also inhabit the biofilm, predating on the organisms and organic particles and contributing to its evolution and dispersal (Majdi et al, 2012). Biofilms therefore form a highly active biological consortium, ready to use organic and inorganic materials from the water phase, and also ready to use light or chemical energy sources.…”

Section: Biofilms In Temporary Streamsmentioning

confidence: 99%

Stream Biofilm Responses to Flow Intermittency: From Cells to Ecosystems

Sabater

Timoner

Borrego

et al. 2016

Front. Environ. Sci.

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Temporary streams are characterized by the alternation of dry and wet hydrological phases, creating both a harsh environment for the biota as well as a high diversity of opportunities for adaptation. These systems are mainly microbial-based during several of these hydrological phases, and those growing on all solid substrata (biofilms) accordingly change their physical structure and community composition. Biofilms experience large decreases in cell densities and biomass, both of bacteria and algae, during dryness. Algal and bacterial communities show remarkable decreases in their diversity, at least locally (at the habitat scale). Biofilms also respond with significant physiological plasticity to each of the hydrological changes. The decreasing humidity of the substrata through the drying process, and the changing quantity and quality of organic matter and nutrients available in the stream during that process, causes unequal responses on the biofilm bacteria and algae. Biofilm algae are affected faster than bacteria by the hydric stress, and as a result the ecosystem respiration resists longer than gross primary production to the increasing duration of flow intermittency. This response implies enhancing ecosystem heterotrophy, a pattern that can be exacerbated in temporary streams suffering of longer dry periods under global change.Keywords: biofilm, dry-rewetting cycle, temporary, intermittency, bacteria, algae, Mediterranean THE RELEVANCE OF TEMPORARY STREAMS IN THE WORLDFlow intermittency is part of the natural hydrology for streams and rivers, especially in arid and semi-arid landscapes. Temporary streams, or those that cease to flow at some points in space and time along their course, are a large fraction of many river networks, basically in tributaries of small order, but also in segments in the middle and lower parts of river networks. The number of temporary streams has been probably underestimated , as it appears from the application of novel on-site sensors, advances in remote sensing, and new modeling approaches. Flow intermittency has been estimated to account for 69% of first-order streams below 60 • , and up to 34% of larger order rivers (Raymond et al., 2013). Flow intermittency produces periodic or eventrelated loss of hydrologic connectivity between stream compartments, with consequences for all the processes ongoing in a waterway. Thus, flow intermittency triggers a chain of cascading effects eventually affecting water chemistry and biogeochemistry, as well as biodiversity, and ultimately community structure and ecosystem functioning.The direct implications of climate change and anomalous climatic events on flow regime are behind of the increasing temporality of many streams and rivers. Complex planetary scale processes, as well as local processes, may justify these situations. Anomalies such as the El Niño

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Section: Biofilms In Temporary Streamsmentioning

confidence: 99%

Stream Biofilm Responses to Flow Intermittency: From Cells to Ecosystems

Sabater

Timoner

Borrego

et al. 2016

Front. Environ. Sci.

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“…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). …”

Section: Study Sitementioning

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.…”

mentioning

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“…Water height and streambed flow velocity were measured (mean of 3 measurements flanking the sampling area) on each sampling occasion with a flowmeter (Flo-Mate 2000, FlowTronic). Days after flood were estimated as the number of days between a given sampling occasion and the last critical flood (MDD > 300 m 3 s −1; Majdi et al 2012a). Water temperature, conductivity, pH and dissolved O 2 were measured with an automated multiparameter probe (YSI 6000, Yellow Springs Instruments), which was permanently set 5 cm above the streambed.…”

mentioning

confidence: 99%

“…During these periods, the maturing biofilm shifts towards more heterotrophic assemblages (Peterson et al 1990, Boulêtreau et al 2006 and is able to host relevant consumer densities. During September 2009, 90 to 140 meioinvertebrates (mostly nematodes, rotifers and chironomids) dwelled in each square centimetre of biofilm (Majdi et al 2012a). Although we did not detect meiofaunal density as a significant factor shaping biofilm diatom composition, it is possible that meiofaunal activity could disrupt mat cohesion and could further favour self-detachment processes (e.g.…”

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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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The relationship between epilithic biofilm stability and its associated meiofauna under two patterns of flood disturbance

Cited by 43 publications

References 75 publications

Stream Biofilm Responses to Flow Intermittency: From Cells to Ecosystems

Stream Biofilm Responses to Flow Intermittency: From Cells to Ecosystems

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

The food web perspective on aquatic biofilms

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