The biofilm polysaccharide matrix: A buffer against changing organic substrate supply?

Freeman, Christopher; Lock, Maurice A.

doi:10.4319/lo.1995.40.2.0273

Cited by 171 publications

(85 citation statements)

References 26 publications

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“…In streams, biofilms adsorb, retain, amplify and transform organic substances and nutrients in the matrix 100,101 (see the figure, part c), thereby accumulating substances that are otherwise highly diluted in the streamwater, such as dissolved organic carbon or contaminants. These solutes become concentrated in biofilms via adsorption to the matrix or incorporation into microbial biomass and subsequent release to the extracellular space 100,101 .…”

Section: Several Crucial Questions Relating To the Biology Of Stream mentioning

confidence: 99%

“…These solutes become concentrated in biofilms via adsorption to the matrix or incorporation into microbial biomass and subsequent release to the extracellular space 100,101 . Biofilms have reflective characteristics similar to those provided by an ecological boundary; the resident microbiome may sort and reflect invading microorganisms 102 with consequences for local community assembly and downstream release of microorganisms.…”

Section: Several Crucial Questions Relating To the Biology Of Stream mentioning

confidence: 99%

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The ecology and biogeochemistry of stream biofilms

et al. 2016

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The perception that most microorganisms live as complex communities that are attached to surfaces has profoundly changed microbiology over the past decades. Most, if not all, bacteria can form biofilms, which are communities of cells embedded in a porous extracellular matrix.Dental plaque, the microorganisms on catheters and implants that cause persistent infections and the fouling of ship hulls and pipework are all examples of biofilms with important implications for public health and industrial processes. Most contemporary biofilm research rests on the discovery made more than 35 years ago by Maurice Lock, Gill Geesey and Bill Costerton: bacteria attached to surfaces dominate microbial life in streams [1][2][3] . These microbiologists pioneered research into stream biofilms, also termed periphyton or epilithon, and described them as complex aggregates of bacteria, algae, protozoa, fungi and meiobenthos. The early study of stream biofilms also highlighted the relevance of interactions between microbial phototrophs and heterotrophs for energy fluxes and the role of the biofilm matrix as the site of extracellular enzyme activity and adsorption of dissolved organic matter (DOM) 3,4 .Since these early days, the study of the ecology and biogeochemistry of stream biofilms has slowly developed in the wake of thriving research on bacterial biofilms -often comprising 3 only a single strain, of interest to medical microbiology, rather than the polymicrobial communities found in stream biofilms -and on the microbial ecology of marine and lake planktonic communities 5 . Unlike bacterial biofilms grown in the laboratory, biofilms in streams are continuously exposed to a diverse inoculum that includes bacteria, archaea, algae, fungi, protozoa and even metazoa. These diverse biological 'building blocks', when combined with the dynamic flow of streamwater, generate biofilms with inherently complex and varying physical structures that have implications for microbial functioning and ecosystem processes 6 . In streams, biofilms are key sites of enzymatic activity 7 , including organic matter cycling, ecosystem respiration and primary production and, as such, form the basis of the food web.Why should we study the ecology and biogeochemistry of stream biofilms? Streams sculpt the continental surface, forming dense and conspicuous channel networks that can be thought of as ecological arteries that perfuse the landscape. Streams are connected to their catchments through various surface and subsurface flow paths and notably through the hyporheic zone in the streambed at the interface between groundwater and streamwater 8 . Microbial cells, solutes and particles enter streams through these flow paths and, en route to downstream ecosystems and ultimately to the oceans, they may interact with the biofilms that colonize the large surface area provided by the streambed as a 'microbial skin' (BOX 1). As a result, the streambed and its biofilm microbiome contribute to biogeochemical fluxes 8 . Indeed, stream biofilms are now recognized as su...

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Section: Several Crucial Questions Relating To the Biology Of Stream mentioning

confidence: 99%

Section: Several Crucial Questions Relating To the Biology Of Stream mentioning

confidence: 99%

The ecology and biogeochemistry of stream biofilms

et al. 2016

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“…The polyanionic polysaccharide matrix in the biofilm can capture OC and other nutrients from the stream water by ion exchange. Microbes use these resources as energy sources (Freeman and Lock 1995;Storey et al 1999). Denitrification rates can be higher in biofilms than in other sites such as stream water due to the supply of a highly-degradable OC and nutrients from biofilms (Howard-Williams et al 1989;Christensen et al 1990;Mariñelarena and Giorgi 2001;Bastviken et al 2003;Toet et al 2003;Venterink et al 2003).…”

Section: Discussionmentioning

confidence: 99%

Factors Controlling Sediment Denitrification Rates in Grassland and Forest Streams

Kim¹

2014

Terr. Atmos. Ocean. Sci.

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Sediment denitrification is an important nitrate (NO 3 -) removal process from agricultural streams. The direct and indirect factors that control denitrification rates in tributary sediments can vary depending on the types of agricultural activities and vegetation. Our research investigated (1) tributary sediment denitrification rates in a grassland stream affected by pasture ecosystems and a forest stream affected by N fertilization; and (2) the environmental factors that determine denitrification rates in tributary sediments. The denitrification enzyme activity (DEA) in grassland stream sediments is positively correlated with precipitation likely due to the increased nutrient exchange rates between stream water and sediments, and was higher than in forest stream sediments, leading to a decrease in NO 3 -concentration ([NO 3 -]) in stream sediments. The DEA in riparian sediments was regulated by carbon concentrations and did not contribute to NO 3 -removal from the riparian sediment in grassland and forest streams. Thus, environmental factors affected by different types of agricultural activities and vegetation might regulate denitrification rates and in agricultural stream ecosystems.

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“…For instance, the ecosystem service (Paterson et al 2008) of particle capture and retention is of great importance to sediment systems in balancing the replacement of material lost by tidal erosion (Verney et al 2006) or wave action (Andersen et al 2007), enhancing the nutrient status (Freeman and Lock 1995) and offering binding sites for pollutants (Ghosh et al 2003). This biofilm adhesion can be measured with high sensitivity, and small changes in developing biofilms can be demonstrated that would be unnoticed using established erosion devices.…”

Section: Comments and Recommendationsmentioning

confidence: 99%

Surface adhesion measurements in aquatic biofilms using magnetic particle induction: MagPI

Larson¹,

Lubarsky²,

Gerbersdorf³

et al. 2009

Limnology & Ocean Methods

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Natural sediment stability is a product of interacting physical and biological factors, and whereas stability can be measured, few techniques allow sensitive assessment of the sediment surface as conditions change. For example, stability gradually increases as a biofilm develops or as salinity rises, or it might be influenced by toxic compounds. This article introduces a new technique (magnetic particle induction: MagPI) based on the magnetic attraction of specially produced fluorescent ferrous particles. The test particles are added to a surface and subjected to an incrementally increasing magnetic field produced by permanent magnets or electromagnets. There is a strong correlation between magnetic flux density (mTesla) and distance from the surface (r 2 = 0.99) for permanent magnets and between magnetic flux density and the current supplied to an electromagnet (r 2 > 0.95). The magnetic force at which the particles are recaptured is determined as a measure of surface adhesion. MagPI therefore determines the "stickiness" of the surface, whether a biofilm, sediment, or other material. The average magnetic flux density required to remove test particles from diatom biofilms (15.5 mTesla) was significantly greater than from cyanobacterial biofilms (10 mTesla). Controls of fine glass beads showed little adhesion (2.2 mTesla). Surface adhesion is an important bed property reflecting the sediment system's potential to capture and retain new particles and accumulate material. MagPI offers a straightforward and economic way to determine the surface adhesion of a variety of surfaces rapidly and with precision. The technique may have applications in physical, environmental, and biomedical research.

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The biofilm polysaccharide matrix: A buffer against changing organic substrate supply?

Cited by 171 publications

References 26 publications

The ecology and biogeochemistry of stream biofilms

The ecology and biogeochemistry of stream biofilms

Factors Controlling Sediment Denitrification Rates in Grassland and Forest Streams

Surface adhesion measurements in aquatic biofilms using magnetic particle induction: MagPI

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