| Title | In situ observations of temporary rivers dry sediments: chemical quality and microbial properties |
| Abstract | Temporary rivers are widespread in arid and semiarid climatic regions
where they represent a direct source of water for human purposes.
These systems are characterised by drastic changes of hydrological
conditions where the duration of the dry phase is expected to
increase under climate change. The hydrological regime regulates the
deposition and re-suspension of the streambed benthic detritus as
well as the biogeochemical processes. Sediments play an important
role in these processes representing the element of continuity
between flowing and dry period. In temporary rivers drying period is
the most crucial as the suspended materials settle on the sediment
(including pollutants) and the aquatic biota must pass through a
"bottle neck" until the first flow arrives. Heterotrophic microbial
communities play an important role in the food web channelling the
C-flux from dissolved organic matter to biomass. Benthic microbial
communities can adopt specific strategies to survive the drought,
affecting organic matter quality and bioavailability with the potential
to change the water quality when flow resumes. Drying imposes
such physiological constraints that microbial communities from
different temporary rivers may adopt similar functional strategies to
survive i.e. the conservation of key processes useful for carbon and
nutrient uptake. The first objective of this experimental work was to
provide a cross view of hydrological regime together with chemical
and microbial properties of dry sediments. To achieve this objective,
sediments from five temporary rivers (Candelaro River basin, southern
Italy) were analysed at the end of the dry period (early autumn) before
flow resumption. Sediments were analysed for physical-chemical
parameters (temperature, texture, water content, pH, conductivity,
mineral composition, ash free dry weight, total organic carbon
and nitrogen, pesticides and heavy metals concentrations) and
microbial descriptors (prokaryotic biomass, DAPI stain; fungi biomass,
ergosterol; total live biomass, ATP, luminescence; four extracellular
enzyme activities, fluorescence technique; community respiration
rates ETS; Biolog(TM)analyses). The second objective was to predict the
impact of microbial processes onto carbon and nutrient fluxes at
given dry conditions by analysing microbial properties of collected
and historical data. This could help in elucidating biogeochemical
processes active under these extreme conditions and their potential
implications for the aquatic environment. |
| Source | XIX Conference of the Iberian Association of Limnology Inland waters and XXI century challenges: from scientific knowledge to environmental management, Coimbra, Portuga, 24 - 29 June 2018 |
| Keywords | temporary riverssedimentspesticidesbioamassmicrobial communityfunctional propertiesbiomass |
| Year | 2018 |
| Type | Abstract in atti di convegno |
| Authors | Zoppini A, Melita M, Casentini B, Laratta B, Pescatore T, De Girolamo AM |
| Text | 391918 2018 temporary rivers sediments pesticides bioamass microbial community functional properties biomass In situ observations of temporary rivers dry sediments chemical quality and microbial properties Zoppini A, Melita M, Casentini B, Laratta B, Pescatore T, De Girolamo AM IRSA CNR, IRSA CNR, IRSA CNR, IBAF CNR, IRSA CNR, IRSA CNR Published version http //www.limnologia2018.org/images/Book_of_abstracts.pdf XIX Conference of the Iberian Association of Limnology Inland waters and XXI century challenges from scientific knowledge to environmental management Coimbra, Portuga 24 29 June 2018 Internazionale Contributo Temporary rivers are widespread in arid and semiarid climatic regions where they represent a direct source of water for human purposes. These systems are characterised by drastic changes of hydrological conditions where the duration of the dry phase is expected to increase under climate change. The hydrological regime regulates the deposition and re suspension of the streambed benthic detritus as well as the biogeochemical processes. Sediments play an important role in these processes representing the element of continuity between flowing and dry period. In temporary rivers drying period is the most crucial as the suspended materials settle on the sediment including pollutants and the aquatic biota must pass through a bottle neck until the first flow arrives. Heterotrophic microbial communities play an important role in the food web channelling the C flux from dissolved organic matter to biomass. Benthic microbial communities can adopt specific strategies to survive the drought, affecting organic matter quality and bioavailability with the potential to change the water quality when flow resumes. Drying imposes such physiological constraints that microbial communities from different temporary rivers may adopt similar functional strategies to survive i.e. the conservation of key processes useful for carbon and nutrient uptake. The first objective of this experimental work was to provide a cross view of hydrological regime together with chemical and microbial properties of dry sediments. To achieve this objective, sediments from five temporary rivers Candelaro River basin, southern Italy were analysed at the end of the dry period early autumn before flow resumption. Sediments were analysed for physical chemical parameters temperature, texture, water content, pH, conductivity, mineral composition, ash free dry weight, total organic carbon and nitrogen, pesticides and heavy metals concentrations and microbial descriptors prokaryotic biomass, DAPI stain; fungi biomass, ergosterol; total live biomass, ATP, luminescence; four extracellular enzyme activities, fluorescence technique; community respiration rates ETS; Biolog TM analyses . The second objective was to predict the impact of microbial processes onto carbon and nutrient fluxes at given dry conditions by analysing microbial properties of collected and historical data. This could help in elucidating biogeochemical processes active under these extreme conditions and their potential implications for the aquatic environment. Abstract in atti di convegno marcomelita MELITA MARCO tanitapescatore PESCATORE TANITA bruna.laratta LARATTA BRUNA annamaria.degirolamo DE GIROLAMO ANNA MARIA barbara.casentini CASENTINI BARBARA annamaria.zoppini ZOPPINI ANNAMARIA TA.P04.032.002 Ruolo delle comunita microbiche nei cicli biogeochimici e nella degradazione degli inquinanti |
