Predictable hydrodynamic conditions explain temporal variations in the density of benthic foraging seabirds in a tidal stream environment

Tidal stream turbines could have several direct impacts upon pursuit-diving seabirds foraging within tidal stream environments (mean horizontal current speeds > 2 ms−1), including collisions and displacement. Understanding how foraging seabirds respond to temporally variable but predictable hydrodynamic conditions immediately around devices could identify when interactions between seabirds and devices are most likely to occur; information which would quantify the magnitude of potential impacts, and also facilitate the development of suitable mitigation measures. This study uses shore-based observational surveys and Finite Volume Community Ocean Model outputs to test whether temporally predictable hydrodynamic conditions (horizontal current speeds, water elevation, turbulence) influenced the density of foraging black guillemots Cepphus grylle and European shags Phalacrocorax aristotelis in a tidal stream environment in Orkney, United Kingdom, during the breeding season. These species are particularly vulnerable to interactions with devices due to their tendency to exploit benthic and epi-benthic prey on or near the seabed. The density of both species decreased as a function of horizontal current speeds, whereas the density of black guillemots also decreased as a function of water elevation. These relationships could be linked to higher energetic costs of dives in particularly fast horizontal current speeds (>3 ms−1) and deeper water. Therefore, interactions between these species and moving components seem unlikely at particularly high horizontal current speeds. Combining this information, with that on the rotation rates of moving components at lower horizontal current speeds, could be used to assess collision risk in this site during breeding seasons. It is also likely that moderating any device operation during both lowest water elevation and lowest horizontal current speeds could reduce the risk of collisions for these species in this site during this season. The approaches used in this study could have useful applications within Environmental Impact Assessments, and should be considered when assessing and mitigating negative impacts from specific devices within development sites.

Modelling impacts and recovery in benthic communities exposed to localised high CO2

Regulations pertaining to carbon dioxide capture with offshore storage (CCS) require an understanding of the potential localised environmental impacts and demonstrably suitable monitoring practices. This study uses a marine ecosystem model to examine a comprehensive range of hypothetical CO2 leakage scenarios, quantifying both impact and recovery time within the benthic system. Whilst significant mortalities and long recovery times were projected for the larger and longer term scenarios, shorter-term or low level exposures lead to reduced projected impacts. This suggests that efficient monitoring and leak mitigation strategies, coupled with appropriate selection of storage sites can effectively limit concerns regarding localised environmental impacts from CCS. The feedbacks and interactions between physiological and ecological responses simulated reveal that benthic responses to CO2 leakage could be complex. This type of modelling investigation can aid the understanding of impact potential, the role of benthic community recovery and inform the design of baseline and monitoring surveys.

Modelling impacts and recovery in benthic communities exposed to localised high CO2

Regulations pertaining to carbon dioxide capture with offshore storage (CCS) require an understanding of the potential localised environmental impacts and demonstrably suitable monitoring practices. This study uses a marine ecosystem model to examine a comprehensive range of hypothetical CO2 leakage scenarios, quantifying both impact and recovery time within the benthic system. Whilst significant mortalities and long recovery times were projected for the larger and longer term scenarios, shorter-term or low level exposures lead to reduced projected impacts. This suggests that efficient monitoring and leak mitigation strategies, coupled with appropriate selection of storage sites can effectively limit concerns regarding localised environmental impacts from CCS. The feedbacks and interactions between physiological and ecological responses simulated reveal that benthic responses to CO2 leakage could be complex. This type of modelling investigation can aid the understanding of impact potential, the role of benthic community recovery and inform the design of baseline and monitoring surveys.

Climate-Driven Range Shifts Within Benthic Habitats Across a Marine Biogeographic Transition Zone.

Anthropogenic climate change is causing unprecedented rapid responses in marine communities, with species across many different taxonomic groups showing faster shifts in biogeographic ranges than in any other ecosystem. Spatial and temporal trends for many marine species are difficult to quantify, however, due to the lack of long-term datasets across complete geographical distributions and the occurrence of small-scale variability from both natural and anthropogenic drivers. Understanding these changes requires a multidisciplinary approach to bring together patterns identified within long-term datasets and the processes driving those patterns using biologically relevant mechanistic information to accurately attribute cause and effect. This must include likely future biological responses, and detection of the underlying mechanisms in order to scale up from the organismal level to determine how communities and ecosystems are likely to respond across a range of future climate change scenarios. Using this multidisciplinary approach will improve the use of robust science to inform the development of fit-for-purpose policy to effectively manage marine environments in this rapidly changing world.

Climate-Driven Range Shifts Within Benthic Habitats Across a Marine Biogeographic Transition Zone.

Anthropogenic climate change is causing unprecedented rapid responses in marine communities, with species across many different taxonomic groups showing faster shifts in biogeographic ranges than in any other ecosystem. Spatial and temporal trends for many marine species are difficult to quantify, however, due to the lack of long-term datasets across complete geographical distributions and the occurrence of small-scale variability from both natural and anthropogenic drivers. Understanding these changes requires a multidisciplinary approach to bring together patterns identified within long-term datasets and the processes driving those patterns using biologically relevant mechanistic information to accurately attribute cause and effect. This must include likely future biological responses, and detection of the underlying mechanisms in order to scale up from the organismal level to determine how communities and ecosystems are likely to respond across a range of future climate change scenarios. Using this multidisciplinary approach will improve the use of robust science to inform the development of fit-for-purpose policy to effectively manage marine environments in this rapidly changing world.

An investigation on benthic macro-invertebrates species diversity as bio-indicators of environmental health in Bahrekan Bay

The purpose of this study was to evaluate benthic macro-invertebrates species diversity as bio-indicators of environmental health in Bahrekan bay (in the Northwest of Persian gulf). Seasonal sediments sampling along 5 transects, 15 stations at 4 replicates (3 replicates for macrobenthos and 1 replicate for sediment analysis) was done from November 2008 to August 2009 by 0.025 m2 Van Veen grab sampler. Physical and chemical parameters of water, grain size analysis, %TOM and Ni and Va concentrations of sediments were assessed through four seasons. Macrobenthic communities after staining and sorting, using stereomicroscope have been identified. Their density in every station and every season calculated. For using of AMBI index, identified macrobenthos according to their sensitivity to stressors and pollutants, categorized into 5 ecological groups and for using of Bentix index categorized into 3 ecological groups. The diversity indices and indicators that showing ecological status were calculated. Also, the differences between physiochemical parameters of sea water, sediments TOM% and grain size, diversity indices in stations and seasons were recorded (P=0.05). The correlation coefficient determined for all parameters. According to the results of grain size analysis, bottom grain size categorized as clay. Highest percent of TOM was belong to autumn (36.39±.075) and lowest was belong to summer (19.01±0.51). Also there was positive correlation (p=0.01) between %TOM and %Clay that showing sediments with lowest size containing highest amounts of organic matters. Ni concentrations in sediments (87.80±21.25)mg/kg showed the amounts over than standards levels but Va concentrations in sediments (53.54±17.60)mg/kg showed the amounts lower than standards level. The highest density of macrobenthos was recorded for summer (8254±485) N/m2 and the lowest density was recorded for spring (3775±172)N/m2. The highest annual density was belong to mollusca (81%) and then polycheates (13%), Others (4%) and crustaceae (2%). The highest diversity was recorded for winter (Simpson index: 0.13±0.01, H':3.47±0.06) and the lowest diversity recorded for autumn (Simpson index: 0.16±0.01, H':3.17±0.06). in all stations, the highest amount of Shanon index was belong to T2S3 station in summer (4.11± 0.32) and the lowest amount was belong to T1S1 station in autumn (2.42± 0.41). The annual mean of Simpson diversity index: (0.15 ±0.04) and Shanon diversity index (3.36±0.03), illustrated that macrobenthos in Bahrekan bay have a good variation. The results of Brilluin and N1 (Number of equally common species) indices confirm the results of Simpson index. For study on the regions that diversity has a little difference between stations, with use of Ni index, the degree of differences could be better ono recognizable. According to the results of AMBI index in all seasons (autumn: 0.46±0.03; summer: 0.22±0.01; annual mean:0.31±0.01) and standards (0.0benthic community health: normal and ecological status: high; 0.2benthic community health: impoverished; ecological status: high) ecological status for all seasons categorized in high status with dominant ecological groups I (sensitive species) but benthic community health were impoverished. The results of Bentix index in all seasons (autumn: 5.07±0.07; summer: 5.57±0.02; annual mean: 5.40±0.02) and standards (4.5

Ingestion of a bacterivorous ciliate by the oyster Crassostrea gigas: Protozoa as a trophic link between picoplankton and benthic suspension-feeders

The linked concepts of 'microbial loop' and 'protozoan trophic link' have been very well documented in filter-feeding microzooplankton such as copepods, but have not been applied to energy transfer to benthic suspension-feeding macrofauna, with the exception of the recent demonstration of heterotrophic flagellate assimilation by mussels. The oyster Crassostrea gigas obtains energy resources by filtering microalgae (similar to 5 to 100 mu m). However, in turbid estuaries, light-limited phytoplanktonic production cannot entirely account for oyster energy requirements. Conversely, picoplankters (<2 mu m), which are main effecters of coastal energy flow and matter cycling, are not efficiently retained by oyster filtration. Ciliate protozoal as both micro-sized cells (similar to 5 to 100 run) and bacteria grazers, may represent a major intermediary in trophic transfer between picoplankton and metazoa. The ciliate Uronema was intensely cultured and labelled, using the cyanobacteria Synechococcus as an auto-fluorescent biomarker. The labelled ciliates were offered as potential prey to oysters. We report here the first experimental evidence of a significant retention and ingestion of ciliates by oysters, supporting the role of protozoa as a realistic trophic link between picoplankters and filter-feeding bivalves and thus enhancing their potential importance in estuarine microbial food webs.

Benthic response to upwelling events off the SE Brazilian coast

The main aim of the present study was to evaluate and compare temporal responses of the benthos in 2 continental shelf areas (Cabo Frio and Ubatuba) off the SE Brazilian coast. In Cabo Frio (23 degrees S, 42 degrees W), the western boundary coastal upwelling of the South Atlantic Central Water (SACW) enhances primary productivity, potentially increasing food supply to the benthic communities via sinking of particulate organic carbon (POC). In contrast, POC fluxes in Ubatuba (23 degrees S, 45 degrees W) are expected to be comparatively lower because SACW remains subsurface. We analyzed the temporal and spatial input of phytodetritus (concentration of chlorophyll a in sediments) and the benthic microbial biomass (estimated by ATP-based carbon content in sediments). Median surface chlorophyll concentration was computed for all daily available SeaWiFS images (from 2001 and 2002) to follow chlorophyll a inputs. All parameters used to investigate benthic responses in the study areas showed consistently higher values in Cabo Frio than in Ubatuba. The results showed that benthic response to upwelling may last months, fueling the microbial communities in the Cabo Frio region.

Phosphoglucose isomerase variability of Cerastoderma glaucum as a model for testing the influence of environmental conditions and dispersal patterns through quantitative ecology approaches

Extreme conditions of coastal lagoons could directly modify the genetic patterns of species. The aim of this work was to investigate the influence of environmental conditions and small scale dispersal patterns on the phosphoglucose isomerase (PGI*) genetic variability of Cerastoderma glaucum from the Mar Menor coastal lagoon. For this purpose, 284 cockles were collected around the perimeter of the lagoon. Vertical polyacrylamide gel electrophoresis was used to scan for PGI* polymorphisms, giving a total of seven alleles. The spatial genetic distribution of the PGI* variability, which seems to be marked by the main circulation in the lagoon, discriminates four hydrological basins. In the central basin, a gradient of allelic composition reflects the circulation forced by the dominant winds and the main channel communicated to the open sea. This result is well supported by the salinity GAM model that defines this gradient. The other three basins are defined by the distribution of fine sand in a more complex model that tries to explain the isolation of the three sites localized inside these basins. The southern, western and northern basins show the lowest degree of interconnection and are considered the most confined areas of the Mar Menor lagoon. This situation agrees with the confinement theory for benthic assemblages in the lagoon. The greater degree of differentiation seen in the Isla del Ciervo population is probably due to recent human intervention on the nearby Marchamalo channel, which has been drained in recent years thus altering the influence of the Mediterranean Sea on the southern basin.

Feeding ecology and life-history strategy of nesting males in a fish with long parental care, Lusitanian toadfish (Halobatrachus didactylus, Batrachoididae)

The Lusitanian toadfish, Halobatrachus didactylus, like other batrachoidids, is a benthic fish species with nesting behaviour during the breeding season. During this prolonged period it engages in mating activities and remains in the nest providing parental care. It is not known whether males feed while providing parental care but it is likely that their limited mobility may restrict their diet and influence their fitness. As a consequence, egg cannibalism could occur as a life-history strategy. The aim of the present study is to ascertain the feeding behaviour of nesting males, in comparison to mature non-nesting males, and to identify potential life-history traits related to egg cannibalism. Nest-holders were sampled from artificial nests placed in an intertidal area of the Tagus estuary, only exposed during spring low tides. The diet of nest-holders was compared with that of non-nesting mature males from the same area, captured by otter trawl. The present study demonstrates that despite their constrained mobility nest-holders feed during the breeding season, although in a more opportunistic fashion than non-nesting males. Nest-holders showed a generalist feeding behaviour, with a more heterogeneous diet. Egg cannibalism was not related to male condition, paternity or brood size but showed a higher incidence early in the season when water temperatures were lower. The results suggest a possible seasonal trade-off strategy between care and energy recovery, triggered by environmental factors, where under unfavourable conditions to sustain viable eggs the male may recover energy by eating eggs, thus benefiting future reproductive success, later in the season.

Effects of different hypoxia timing regimes on a transitional habitat's ( Pialassa Baiona, Ravenna, Italy) benthic community.

The aim of this thesis was to quantify experimentally in the field the effects of different timing regimes of hypoxia on the structure of benthic communities in a transitional habitat. The experiment was performed from 8 July to 29 July 2019 in a shallow subtidal area in Pialassa Baiona (Italy), a lagoon characterized by mixing regimes dominated by the tide. The benthic community was isolated using cylinders 15,5Cm x 20Cm size. Hypoxic conditions were imposed by covering the treated cylinders with a black plastic bag while control cylinders were left uncovered. We created 4 different timing regimes of hypoxia by manipulating both the duration of hypoxia (4 or 8 days) as well as the ratio between the duration of subsequent periods of hypoxia and the duration of a normoxic period between subsequent hypoxic events (D4R3/2, D8R3/2). At the end of each experimental trial, the benthic communities within each pot were retrieved, sieved in the field and subsequent analyzed in the laboratory where organisms were identified and counted. Results showed that benthic organism were generally negatively affected by hypoxic stress events. As expected, longer hypoxic events caused a stronger decrease of benthic community abundance. When the hypoxic events were interrupted by the normoxic event there were two different results. If the hypoxic period was too long, the normoxic period didn’t cause a positive recovery effect, and further decline of the benthic community was observed. Conversely normoxia had positive effects if the period of hypoxia was short enough not to compromise the benthic community. This resulted in a statistically significant interaction between the tested factors Duration and Ratio. Amphipods were the most sensitive organisms to hypoxia. We conclude that the effects of hypoxia can be greatly relieved by short normoxic periods if they happen frequently enough.

The River And The Sea: Fieldwork In Human Ecology And Ethnobiology.

This article is a commentary on the experiences that motivated my decision to become a human ecologist and ethnobiologist. These experiences include the pleasure of studying and of having the sense of being within nature, as well as the curiosity towards understanding the world and minds of local people. In particular, such understanding could be driven by addressing the challenging questions that originate in the interactions of such individuals with their natural surroundings. I have been particularly interested in the sea and the riverine forests that are inhabited by coastal or riverine small-scale fishers. Sharing the distinctive world of these fishers enjoyably incited my curiosity and challenged me to understand why fishers and their families 'do as they do' for their livelihoods including their beliefs. This challenge involved understanding the rationality (or the arguments or views) that underlies the decisions these individuals make in their interaction with nature. This curiosity was fundamental to my career choice, as were a number of reading interests. These reading interests included political economy and philosophy; evolution and sociobiology; evolutionary, human, and cultural ecology; cultural transmission; fisheries; local knowledge; ecological economics; and, naturally, ethnobiology.

Pollination Ecology Of Two Species Of Elleanthus (orchidaceae): Novel Mechanisms And Underlying Adaptations To Hummingbird Pollination.

Relationships among floral biology, floral micromorphology and pollinator behaviour in bird-pollinated orchids are important issues to understand the evolution of the huge flower diversity within Orchidaceae. We aimed to investigate floral mechanisms underlying the interaction with pollinators in two hummingbird-pollinated orchids occurring in the Atlantic forest. We assessed floral biology, nectar traits, nectary and column micromorphologies, breeding systems and pollinators. In both species, nectar is secreted by lip calli through spaces between the medial lamellar surfaces of epidermal cells. Such form of floral nectar secretion has not been previously described. Both species present functional protandry and are self-compatible yet pollinator-dependent. Fruit sets in hand-pollination experiments were more than twice those under natural conditions, evidencing pollen limitation. The absence of fruit set in interspecific crosses suggests the existence of post-pollination barriers between these synchronopatric species. In Elleanthus brasiliensis, fruits resulting from cross-pollination and natural conditions were heavier than those resulting from self-pollination, suggesting advantages to cross-pollination. Hummingbirds pollinated both species, which share at least one pollinator species. Species differences in floral morphologies led to distinct pollination mechanisms. In E. brasiliensis, attachment of pollinaria to the hummingbird bill occurs through a lever apparatus formed by an appendage in the column, another novelty to the knowledge of orchids. In E. crinipes, pollinaria attachment occurs by simple contact with the bill during insertion into the flower tube, which fits tightly around the bill. The novelties described here illustrate the overlooked richness in ecology and morphophysiology in Orchidaceae. This article is protected by copyright. All rights reserved.

Carbapenem stewardship: positive impact on hospital ecology

INTRODUCTION: Excessive group 2 carbapenem use may result in decreased bacterial susceptibility. OBJECTIVE: We evaluated the impact of a carbapenem stewardship program, restricting imipenem and meropenem use. METHODS: Ertapenem was mandated for ESBL-producing Enterobacteriaceae infections in the absence of non-fermenting Gram-negative bacilli (GNB) from April 2006 to March 2008. Group 2 carbapenems were restricted for use against GNB infections susceptible only to carbapenems and suspected GNB infections in unstable patients. Cumulative susceptibility tests were done for nosocomial pathogens before and after restriction using Clinical and Laboratory Standards Institute (CLSI) guide-lines.Vitek System or conventional identification methods were performed and susceptibility testing done by disk diffusion according to CLSI.Antibiotic consumption (t-test) and susceptibilities (McNemar's test) were determined. RESULTS: The defined daily doses (DDD) of group 2 carbapenems declined from 61.1 to 48.7 DDD/1,000 patient-days two years after ertapenem introduction (p = 0.027). Mean ertapenem consumption after restriction was 31.5 DDD/1,000 patient-days. Following ertapenem introduction no significant susceptibility changes were noticed among Gram-positive cocci. The most prevalent GNB were P. aeruginosa, Klebsiella pneumoniae, and Acinetobacter spp. There was no change in P. aeruginosa susceptibility to carbapenems. Significantly improved P. aeruginosa and K. pneumoniae ciprofloxacin susceptibilities were observed, perhaps due to decreased group 2 carbapenem use. K. pneumoniae susceptibility to trimethoprim-sulfamethoxazole improved. CONCLUSION: Preferential use of ertapenem resulted in reduced group 2 carbapenem use, with a positive impact on P. aeruginosa and K. pneumoniae susceptibility.