Macrophyte communities and their impact on benthic fluxes of oxygen, sulphide and nutrients in shallow eutrophic environments

Viaroli, Pierluigi; Bartoli, Marco; Bondavalli, Cristina; Christian, Robert R.; Giordani, Gianmarco; Naldi, Mariachiara

doi:10.1007/978-94-009-1744-6_9

Cited by 65 publications

(39 citation statements)

References 27 publications

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“…In healthy phanerogam meadows, free sulphides are kept at submicromolar levels by oxygen exchanges, also through the rizosphere. In lagoons with submersed vegetation covered by epiphytes and/or with floating macroalgae, the water column becomes laminated and during the biomass decomposition dissolved sulphides are delivered to the water column, without having contact with the sedimentary iron pools (Viaroli et al, 1996(Viaroli et al, , 2006.…”

Section: Discussionmentioning

confidence: 99%

A rapid assessment of the sedimentary buffering capacity towards free sulphides

2008

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Combined field surveys and laboratory studies were conducted in two Italian coastal lagoons, which differ for geomorphology, hydrodynamics and eutrophication degree (Sacca di Goro and Lesina lagoons, Adriatic Sea). Research aimed at assessing with a rapid technique the potential buffering capacity of sedimentary iron towards sulphides. In Spring and Summer 2004, the main pools of iron and sulphides were analysed in the uppermost sediment horizon (0-5 cm) at four stations in each lagoon. In parallel, experiments with laboratory incubations of sediment slurries were carried out at two sites in each lagoon in order to assess the sediment capacity of binding and retaining sulphides. Sediment slurries were kept stirred and anoxic with N 2 purging. Aliquots of dissolved sulphides (DS) were then added and DS concentrations were monitored until they were undetectable. On average, the total reactive iron (RFe), extracted with 6 N HCl, ranged from 170 to 400 lmol cm -3 in the Sacca di Goro stations, and comprised between 40 and 150 lmol cm -3 in the Lesina sites. The labile iron ferric quota (LFe: extractable with 0.5 N HCl) is considered representative of the microbially reducible iron fraction and was highest in spring in Sacca di Goro (up to 20 lmol cm -3 ). Differences among stations evidenced by PCA analysis, can be inferred from RFe, LFe and AVS, which represent the iron buffer and its saturation status, respectively. The sedimentary DS uptake was 6 lmol cm -3 of fresh sediment in Lesina and 8-12 lmol cm -3 in Sacca di Goro, indicating a direct relationship between DS removal and iron availability.

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Section: Discussionmentioning

confidence: 99%

A rapid assessment of the sedimentary buffering capacity towards free sulphides

2008

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“…Owing to the limited hydrodynamic regime, water shallowness, and high organic load, phytotreatment ponds feature environmental conditions commonly found in coastal eutrophic environments, such as highly productive marginal areas of Mediterranean coastal lagoons that are subjected to summer collapse of primary production and anoxia (Castel et al, 1996;Viaroli et al, 1996;De Wit et al, 2001).…”

Section: Study Areamentioning

confidence: 99%

Short-term effect of oxic to anoxic transition on benthic microbial activity and solute fluxes in organic-rich phytotreatment ponds

et al. 2009

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Manipulative experiments to test the short-term effect of oxygen depletion events on microbial activity and benthic fluxes in organic-rich sediments were carried out in March and June 2004. Oxic–anoxic transitions were induced by prolonged dark incubation of sealed sediment cores collected in phytotreatment ponds. Benthic fluxes of oxygen (O2), carbon dioxide (CO2), inorganic nutrients, and free sulfides were measured before (oxic) and after (anoxic) the transition occurred. A multifactorial design was employed for monitoring esoenzymatic activity, heterotrophic bacterial production, total prokaryotic abundance, actively respiring bacterial cells, and the biochemical composition of sedimentary organic matter. The oxic to anoxic transition resulted in a significant increase of esoenzymatic activity and bacterial production in March, due to the profound modification of the benthic community and the release of labile organic compounds which followed the onset of anoxia. In parallel, net efflux rates of dissolved inorganic carbon (DIC) and ammonium (NH4 ?) sharply decreased, soluble reactive phosphorus (SRP) influx reversed, and sulfide was buffered within the oxidized sediments. From March to June, ponds evolved toward oxygen deficit and reducing conditions in the upper sediment horizon, losing benthic fauna and biogeochemical buffering capacity. Thus, the oxic to anoxic transition had a much smaller effect on microbial activity and net flux exchange, while S2- was consistently delivered from the sediment to the water column. Overall data from this study suggest that the shortterm response of benthic microbial activity and solute fluxes to anoxic events may have a significant impact on sediment biogeochemistry (e.g., at the oxic– anoxic interface), and that this impact may vary greatly depending on the sediment features, mainly its organic content and redox condition

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“…Within the context of PNEC and CPER, specific studies were initiated in 1993 with a special focus on macrophyte, zoobenthos and fish communities. The macrophyte role in lagoon functioning was demonstrated for epifaunal assemblages (Parker et al, 2001), sedimentary microbial processes (Hansen et al 2000), and benthic fluxes of oxygen, sulphide and nutrients (Viaroli et al, 1996;Plante-Cuny et al, 1998;Dhargalkar & Shaikh, 2000). The benthic biota is also involved in decomposition and nutrient cycling processes, enhancing the nutrient transfer from the sediment to the water column through bioturbation (Francois et al, 2002).…”

Section: Introductionmentioning

confidence: 97%

Assessment of Coastal Lagoon Quality with Taxonomic Diversity Indices of Fish, Zoobenthos and Macrophyte Communities

et al. 2005

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Lagoons and marshes account for more than 50% of the coastal area in the Languedoc Roussillon region (South of France, Mediterranean Sea). The lagoons are very different in their physical and chemical characteristics, eutrophication level and resource exploitation mode. In this study, different levels of taxonomic diversity and two indices (D + and K + ) based on macrophyte, zoobenthos and fish communities are used to compare three lagoons (Ingril, Pre´vost and Mauguio). Whilst the taxonomic diversity of the fish community seems not influenced by the lagoon characteristics, the benthos community is strongly related to their eutrophication status. With the same sampling effort we identified 7 benthic species in Mauguio, the most impacted lagoon, while 24 species were found in the Ingril lagoon, which is the less impacted one. Overall, the variance of taxonomic distinctness K + appeared as the best indicator of the lagoon eutrophication level. This index is always highest for the Mauguio lagoon, whatever the biotic compartment considered. In a more stable environment like in the Ingril lagoon (lower variations of salinity, temperature or turbidity), K + is low, i.e., the structure of the taxonomic tree is very regular with a relatively homogeneous partition of species among phyla. By contrast, when salinity variations are wide, like in the Mauguio lagoon, the taxonomic tree becomes irregular with some lineages less constrained (many species belonging to the same family), while others are more impacted with a limited number of species in these phyla.

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Macrophyte communities and their impact on benthic fluxes of oxygen, sulphide and nutrients in shallow eutrophic environments

Cited by 65 publications

References 27 publications

A rapid assessment of the sedimentary buffering capacity towards free sulphides

A rapid assessment of the sedimentary buffering capacity towards free sulphides

Short-term effect of oxic to anoxic transition on benthic microbial activity and solute fluxes in organic-rich phytotreatment ponds

Assessment of Coastal Lagoon Quality with Taxonomic Diversity Indices of Fish, Zoobenthos and Macrophyte Communities

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