Variability of macrofaunal assemblages on the surroundings of a brine disposal

Oligotrophic areas harbour low macrofaunal abundance and patchy distribution. In these areas it is necessary to test the reliability of biological indicators, especially those based on taxonomic sufficiency where the level of identification is balanced against the need for ecological information and could affect the efficiency of bioindicators. The BOPA (benthic opportunistic polychaetes and amphipods) index was applied in five coastal areas subjected to different perturbations (aquaculture, harbour, brine, sewage, and thermal pollution) in the Canary archipelago, an oligotrophic area of the Atlantic Ocean. Significant differences in the BOPA index between impact and control sites were only found in the area affected by a harbour. Perturbations such as aquaculture, brine or sewage discharge produce only a weak response of the BOPA index, whereas no effects were observed at thermal pollution‐impacted locations. The BOPA index should be used with caution to establish the ecological status of coastal water bodies in the Canary Islands, since it was only reliable in strongly impacted regions (enlargement harbour works), but did not respond clearly to other man‐induced perturbations.

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“…Variations in sedimentary composition were observed between both surveys, because of swell periods during winter season (Riera et al . ).…”

Section: Methodsmentioning

confidence: 97%

Response of benthic opportunistic polychaetes and amphipods index to different perturbations in coastal oligotrophic areas (Canary archipelago, North East Atlantic Ocean)

Riera

de-la-Ossa-Carretero

2013

Marine Ecology

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“…Pollution from sewage and desalination plants is rapidly diluted in the water column because of the continuous coastal currents. Thus, macrofauna community is not heavily affected by this perturbation, and the composition of polychaetes and amphipods not differ consistently from impacted to control stations (Riera et al, 2012). This situation occurs in offshore fish cages, with a high dispersion of particulate material, e.g.…”

Section: Discussionmentioning

confidence: 93%

Polychaete/amphipod ratios: An approach to validating simple benthic indicators

Dauvin

Andrade

de-la-Ossa-Carretero

et al. 2016

Ecological Indicators

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a b s t r a c tAmong the macro-invertebrates used for the assessment of soft-bottom communities, most polychaetes are classified as tolerant/opportunistic to pollution while amphipods are considered as sensitive. These taxa have been used in several ecological indices, such as the simple abundance ratio between Polychaeta and Amphipoda or the Benthic Opportunist Annelids Amphipods (BO2A) index, to assess the Ecological Quality Status -EcoQs-of soft-bottom communities. In terms of Taxonomic Sufficiency (TS), the polychaete/amphipod ratio (i.e. at the level of the class/order) has been proved to be effective in identifying major changes in benthic communities following disturbances. However, an underlying issue is to assess the acceptable TS limit value needed to state accurately the quality of the benthic environment. We tested three indices using 18 series of observations carried out in five north-eastern Atlantic and Mediterranean zones impacted by oil spills, oil and gas production, brine and urban sewage, harbours and aquaculture farms within impacted and control areas. Similar results to BO2A were obtained when limiting the TS at the level of Polychaete opportunistic families, which required a lower degree of taxonomic expertise, and classifying all amphipods as sensitive taxa. In such a way that the EcoQs given by the BPOFA (Benthic Polychaete Opportunistic Families Amphipods) was very similar to those given by the BO2A (Benthic Opportunistic Annelids Amphipods).

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“…To quantify grain size composition, 100 g sediment from each sampling station was oven dried at 105°C, passed through a graded series of sieves (2 mm, 1 mm, 0.5 mm, 0.25 mm, 0.125 mm and 0.063 mm), and then weighed (Buchanan ). These sieves characterized seven sedimentary types that are widely used in grain‐size studies (Riera, Tuya, Ramos, Rodríguez & Monterroso ). The method of Walkley and Black () was used to determine the organic matter content in the sediment.…”

Section: Methodsmentioning

confidence: 99%

Response of different benthic habitats to off-shore fish cages

et al. 2013

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Off-shore fish farming can increase the organic load of nearby coastal marine ecosystems due to the deposition of fish food and faeces on seabeds. Seagrass meadows are particularly affected by aquaculture activities but there are few empirical data showing differential effects of the same farming activity on multiple habitat types. Here, we assessed over a 2-year period whether macrofaunal assemblages inhabiting sandy bare seabeds and Cymodocea nodosa meadows varied in their macrofaunal community structure to the fish farming activities. We observed high spatial and temporal variability in macrofauna composition and dynamics among seabed habitats and a limited impact of fish cages in their area of influence as compared with control areas. Seagrass meadows showed a higher abundance in macrofauna communities than sandy bare bottoms. Local marine currents could partially explain some results because of their influence on grain size composition. Differences in grain size resulted in higher abundances of the tanaid Apseudes talpa beneath fish cages and the absence of the sensitive amphipod Ampelisca brevicornis. Differences of resilience of seabeds (seagrass meadows and sandy bare bottoms) should be taken into account for environmental monitoring studies of off-shore fish cages. Our results suggest that hydrodynamics are a key factor to determine buffer areas between fish cages and seagrass meadows.

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Variability of macrofaunal assemblages on the surroundings of a brine disposal

Cited by 46 publications

References 27 publications

Response of benthic opportunistic polychaetes and amphipods index to different perturbations in coastal oligotrophic areas (Canary archipelago, North East Atlantic Ocean)

Response of benthic opportunistic polychaetes and amphipods index to different perturbations in coastal oligotrophic areas (Canary archipelago, North East Atlantic Ocean)

Polychaete/amphipod ratios: An approach to validating simple benthic indicators

Response of different benthic habitats to off-shore fish cages

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