Landlocked lagoons are naturally stressed environments. They are strongly influenced by freshwater input which not only varies naturally, but which is also impacted by anthropogenic activities. This ...study investigated the direct influence of freshwater discharges on the distribution patterns and abundance of benthic communities in two neighbouring landlocked coastal lagoons, assessing the whole system and the confluence area of each tributary. Sampling occurred in the wet and dry seasons of 2011 at two distances from freshwater discharge locations. Both lagoons were colonized by species from two different pools, freshwater and marine. Freshwater flow rates had a direct influence on the spatial structure of the benthic communities of brackish-water/freshwater interface areas, where also specific taxa can act as early indicators of freshwater input variations. The intensity of this influence is highly dependent on lagoon size, creating spatial heterogeneity or affecting the entire system. The benthic fauna at the confluence of the tributary that depends almost exclusively on groundwater showed the lowest variability, suggesting that the biogeochemical nature of the groundwater may be a central cause for setting specific ecotones. The results suggest that benthic communities of landlocked coastal lagoons can be highly impacted by flow reduction from freshwater aquifers under drought conditions or water abstraction activities.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
We examined the variation of stygofauna composition collected in wells, along a gradient in groundwater salinity/conductivity in a coastal aquifer from southern Portugal. The studied coastal aquifer ...is considered vulnerable to salinization due to seawater intrusion, caused by overexploitation of the aquifer. Knowing the response of the stygofauna species to present levels of groundwater salinity makes it possible to understand and measure the effects of saltwater intrusion on stygofauna, rendering them potential bioindicators of this environmental pressure. Biotic and abiotic sampling was conducted in six shallow wells located in the fresh-saltwater interface of the Arade estuary along the salinity gradient established in the groundwater from the estuary to inland locations (microSiemens/cm). Groundwater salinity was highly correlated with taxa distribution. The stygobites Eucyclops hadjebensis and Acanthocyclops sensitivus, the cosmopolitan Megacyclops viridis and Cypria ophtalmica were particularly associated with low-salinity conditions, whereas Eucyclops graeteri, Megacyclops brachypus and Daphnia pulicaria were related to high-salinity waters. Multivariate analyses indicated that stygofauna assemblages varied significantly with location. We suggest that stygofauna composition and structure can be a useful complementing tool for monitoring seawater intrusion into coastal aquifers, where reduction or deterioration in groundwater resources is predicted.
A comparative study on climate change and its impacts on coastal aquifers is performed for three Mediterranean areas. Common climate scenarios are developed for these areas using the ENSEMBLES ...projections that consider the A1b scenario. Temperature and precipitation data of three climate models are bias corrected with two different methods for a historic reference period, after which scenarios are created for 2020–2050 and 2069–2099 and used to calculate aquifer recharge for these periods based on two soil water budget methods. These multiple combinations of models and methods allow incorporating a level of uncertainty into the results. Groundwater flow models are developed for the three sites and then used to integrate future scenarios for three different parameters: (1) recharge, (2) crop water demand, and (3) sea level rise. Short-term predictions are marked by large ranges of predicted changes in recharge, only showing a consistent decrease at the Spanish site (mean 23 %), particularly due to a reduction in autumn rainfall. The latter is also expected to occur at the Portuguese site, resulting in a longer dry period. More frequent droughts are predicted at the Portuguese and Moroccan sites, but cannot be proven for the Spanish site. Toward the end of the century, results indicate a significant decrease (mean >25 %) in recharge in all areas, though most pronounced at the Portuguese site in absolute terms (mean 134 mm/year) and the Moroccan site in relative terms (mean 47 %). The models further predict a steady increase in crop water demand, causing 15–20 % additional evapotranspiration until 2100. Scenario modeling of groundwater flow shows its response to the predicted decreases in recharge and increases in pumping rates, with strongly reduced outflow into the coastal wetlands, whereas changes due to sea level rise are negligible.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Communities located in the interface between marine/brackish and freshwater habitats are likely to be early responders to climatic changes as they are exposed to both saline and freshwater ...conditions, and thus are expected to be sensitive to any change in their environmental conditions. Climatic effects are predicted to reduce the availability of groundwater, altering the hydrological balance on estuarine-aquifer interfaces. Here, we aimed to characterise the estuarine faunal community along a gradient dependent on groundwater input, under a predicted climatic scenario of reduction in groundwater discharge into the estuary. Sediment macrofauna was sampled along a salinity gradient following both the wet and dry seasons in 2009. Results indicated that species abundance varied significantly with the salinity gradient created by the groundwater discharge into the estuarine habitat and with sampling time. The isopode
Cyathura carinata (Krøyer, 1847) and the polychaetes
Heteromastus filiformis (Claparède, 1864) and
Hediste diversicolor O.F. Muller, 1776 were associated with the more saline locations, while oligochaeta and Spionidae were more abundant in areas of lower salinity. The polychaete
Alkmaria romijni Horst, 1919 was the dominant species and ubiquitous throughout sampling stations. This study provides evidence for estuarine fauna to be considered as a potentially valuable indicator of variation in the input of groundwater into marine-freshwater interface habitats, expected from climatic pressures on aquifer levels, condition and recharge rates. For instance, a reduction in the abundance of some polychaete species, found here to be more abundant in freshwater conditions, and increasing Oligochaeta found here on higher salinities, can potentially be early warnings of a reduction in the input of groundwater into estuaries. Estuarine benthic species are often the main prey for commercially important fish predators such as in our case study, making it important to monitor the aquatic habitat interfaces taking into consideration the estuarine macrobenthos and groundwater availability in the system.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Issue Title: Theme: Biodiversity in Enclosed Seas and Artificial Marine Habitats Proceedings of the 39th European Marine Biology Symposium, held in Genoa, Italy, 21-24 July 2004 This study was ...carried out on the "Faro/Ancão" artificial reef (AR), located off Faro, deployed in May 2003. We aimed to characterise early macrobenthic community colonisation of two concrete AR groups located at different depths (16 m and 20 m depth) and to test the effect of reef structure on these communities. The non-colonial organisms were counted; barnacles and colonial species were quantified using biomass. Multivariate analyses indicated that early macrobenthic communities (6 months of immersion) were affected by depth, and that barnacles and colonial species were also affected by reef structure. Univariate analyses showed that the biomass of barnacles and colonial species was significantly different among reefs and layers of modules. Both AR groups were characterised by the species Balanus amphitrite, Gregariella subclavata, Musculus cf. subpictus, Paleanotus cf. bellis and Syllidia armata. Jassa marmorata and Bugula neritina were characteristic species at 16 m depth, particularly on the AR Upper layer of modules, whereas Anomia ephippium was particularly common at 20 m, especially on the Lower layer of modules.PUBLICATION ABSTRACT
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Santo André is an enclosed brackish water coastal lagoon with temporary connections to the sea by a man-made channel. The exchange and mixture of saltwater and freshwater is irregular and the lagoon ...may show daily and seasonal fluctuations, but also long-term variation. Different benthic communities may be present along the annual cycle according to the magnitude of episodic freshwater and sea water inputs.
In the last 30 years the communication with the sea has followed different regimes from year to year and, as a consequence, macrobenthic communities, assessed several times during the period before the opening to the sea, shifted from freshwater to marine affinities. Major differences were found between 1979 and 2010, with a preponderance of species with marine affinity, and the 1980s in which the organisms with freshwater affinity prevailed. Benthic communities are frequently used to assess aquatic environmental condition. Metrics used in the indices currently under discussion to assess ecological status of aquatic ecosystems within the scope of European Water Framework Directive were applied to Santo André data and the applicability of these metrics to assess quality in this coastal land-locked lagoon was discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
. A general description of rocky shore distribution patterns (“zonation”) along the whole Portuguese coast is given to provide the context for comparisons of distribution patterns of mid‐shore ...organisms. In order to test if there was any variation in species distribution and abundance in the upper and lower mid‐shore zone (eulittoral) along the entire intertidal Portuguese coast, three main regions were studied (north, centre and south) and nine shores were visited in each region. At each one of the 27 locations, the shore was levelled and a general qualitative description was made, which also aided stratification of subsequent quantitative sampling. An upper zone (littoral fringe) characterised by the presence of encrusting lichens, small littorinid gastropods and cyanobacteria was found on most of the shores along the Portuguese coast. The mid‐shore zone (eulittoral) is essentially dominated by barnacles and sometimes mussels. The distribution patterns observed on the lower shore (sub‐littoral fringe) showed a distinction between northern shores, where large brown algae are present, and shores located in the central and southern regions, essentially dominated by red algal turf species. Multidimensional analysis and the ANOSIM test have revealed clear differences in the structure of the upper and lower mid‐shore zone. Within each level, the northern region was considerably different from the south and central regions. SIMPER analysis revealed the species which contributed to the separation between shore levels and regions. It has also given important information on the geographical decline in abundance of species.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The characteristic high variability and low predictability of coastal lagoons, due to strong changes in marine and freshwater inputs, make these ecosystems an interesting case-study. The small ...Melides landlocked coastal lagoon in SW Portugal is a paradigmatic example, with a biological community highly stressed by these phenomena. Benthic macroinvertebrate samples were collected in 1998/99 and 2009 and each year, in different seasons and addressing different environmental conditions influenced by the connection to the sea and rainfall regime. Major spatial and temporal patterns in benthic communities were investigated using some invertebrate attributes (e.g. community composition, density, species richness and diversity). A very low taxonomic species richness and diversity was found in the Melides lagoon and only a much reduced number of species occurred along all sampling periods and in both sampling campaigns. Although the colonization events play a crucial role, the persistence of the observed species was mainly associated to abiotic factors, such as salinity, temperature and dissolved oxygen. Despite the potential reduction in anthropogenic pressure, by the construction of a sewage treatment plant and a reduction of urban occupation, the ecological status did not improve and the high level of natural environmental variably in the lagoon seems to be the dominant stressor influencing benthic invertebrate communities.
In a mesocosm experiment, pigment levels, organic matter and the structure of macroinvertebrate community were compared in two linked wetland systems encompassing fish-farm pond and natural ...reservoir. A stratified sampling design was applied, and treated experimental azoic sediment was placed in suspended boxes. The set of box was used to follow cumulative colonization period and single-month colonization approach for the study of macrofauna and biochemical parameters (organic matter, chlorophyll
a
and phaeopigments). There were significant differences between systems for the abiotic and community variables and polychaete diversity. Regarding the structure of macroinvertebrate community, the pond system appears to have higher abundance than the natural system. Monthly fluctuation was observed for abiotic variable and community variables in both systems, but polychaete diversity indices did not vary monthly in the pond system, which suggests that diversity indices in disturbed systems do not follow the organic matter variation. The correlation coefficient was also tested within abiotic and community variables for both systems. In the pond system, the organic matter was strongly related with chlorophyll
a
, carotenoid and phaeopigments. Due to the fact that the source of OM in the pond system is allochthonous, phaeopigments level is likely not to be directly affected by organic matter enrichment, but organic matter inputs create the high primary production and consequently affect the phaeopigments level. Polychaete abundance was positively correlated with the load in organic matter for both reservoir and pond systems, but the correlation coefficient between organic matter and polychaete diversity indices was higher in reservoir than in the pond system. The Moss index was used to indicate the production and degradation state of the systems, and it represented the natural reservoir in a higher production phase than the fish pond, and later on, the monthly variation of the percentage of degradation confirms the pond system in a more decayed state than the natural reservoir system. This study shows that although the organic matter and phaeopigments level tend to be higher in disturbed system, this does not necessarily favor all species, and more sensitive species are endangered of getting displaced by opportunistic species in systems with anthropogenic impact.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The present work analysed the potential impacts of the enrichment of semi-intensive production earthen ponds with the ragworm
Hediste diversicolor in the benthic dynamics and natural productivity. ...The macrobenthos and sediment characteristics were analysed in two enriched ponds and two control ponds in May, June and September 2005. The number of species, Margalef species richness and biomass (AFDW) were generally significantly higher in enriched than in control ponds, while for abundance no clear pattern was visible. Multivariate analysis showed differences in macrobenthic community structure of control and enriched ponds. Differences were also visible when the introduced species was removed from the data set, indicating that differences were mainly due to changes in other species abundance. In general, gastropods (
Akera bullata,
Jujubinus striatus,
Hydrobia ulvae, Rissoidae), bivalves (
Abra ovata,
Cerastoderma spp.), crustaceans (
Ampithoe rubricata,
Dexamine spinosa,
Gammarus insensibilis,
Gammarella fucicola,
Iphinoe tenella), and also some polychaetes (
Desdemona ornata,
Terebella spp.,
Syllis gracilis and
Neanthes caudata) greatly increased their abundances in enriched ponds. On the other hand, the abundance of Tubificidae,
Capitella spp.,
Pseudopolydora paucibranchiata,
Corophium acherusicum, and
Mesopodopsis slabberi decreased. The organic matter content was significantly lower in enriched ponds, probably due to the positive impact of the polychaetes on sediment reworking, resulting in higher organic matter mineralization. Overall the present study indicates that stocking of earthen production ponds with
H. diversicolor significantly altered community structure of benthic invertebrates and may improve environmental conditions for fish production by reducing the organic matter accumulation in pond sediments.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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