Is there a significant relationship between the benthic status of an area,determined by two broadly-used indices,and best professional judgment?

Two benthic indices to assess the quality status (the AZTI's Marine Biotic Index (AMBI) and multivariate-AMBI (M-AMBI)) are being used extensively in different habitats worldwide. We try to interpret what is behind these indices making them suitable for different habitats. To demonstrate that, we used best professional judgment (BPJ), applying it to a dataset from southern Chile, to determine the criteria proposed by 12 experts in assessing the status. The experts were provided with raw species abundance data, from 12 stations within a gradient of disturbance, from unaffected to severely affected. There was a very good agreement among experts (kappa values 0.72–0.77), with highly significant (p < 0.001) correlation between BPJ and AMBI and M-AMBI classifications, and an agreement of 76.4% and 81.9%, respectively. When comparing BPJ in Chile with other results in Europe, USA and northern Africa, similar patterns can be identified: (i) the number of criteria identified for classification is very high (range 7–12); (ii) the experts use several criteria together in the BPJ assessment; and (iii) the rank of the most important criteria is indicator species, richness, and diversity/dominance. These criteria are included in indices such as AMBI and M-AMBI. Hence, although experts are classifying samples subjectively when applying BPJ, they are corroborated in their opinions when using such indices. This fact can explain why these indices are so widely used.     

Use of the size fractionation of the macrobenthic biomass for the rapid assessment of benthic organic enrichment

A new biomass index for monitoring the impact of marine fish cage farming on the benthic environment was evaluated at seven commercial fish farms in the eastern Mediterranean. At each farm, stations near and further away from the cages were sampled for macrofauna and geochemical variables during July 2001, and March and October 2002. Benthic samples were sequentially sieved through 1.0 and 0.5 mm mesh screens and a biomass fractionation index (BFI) was estimated as follows: biomass having passed through 1.0 mm and retained on 0.5 mm sieve only/total biomass (biomass retained on 1.0 mm + 0.5 mm sieve). BFI was quantitatively assessed and compared with the geochemical faunistic and management practice data. BFI was found to decrease consistently with distance from fish cages and particularly after 10 m from the edge of the cages. At all farms, BFI was found to be significantly correlated with distance, redox potential and organic carbon. Multiple regression analysis showed that BFI incorporates various components of sediment geochemistry (sediment grain size and total organic carbon) as well as distance and feeding rates. Although BFI needs to be further tested in different geographic locations and under different management practices, the results seem to be promising for long-term monitoring programmes since it provides a simple and inexpensive solution for assessing the effects of benthic organic enrichment due to fish farm activities.     

Assessing benthic health in stressed subtropical estuaries,eastern Florida,USA using AMBI and M-AMBI

The Indian River Lagoon (IRL) and the St. Lucie Estuary (SLE), both located in Florida, USA, are affected by a variety of anthropogenic pressures. Benthic macroinvertebrates have been monitored quarterly since February 2005, at 15 stations, in order to assess benthic health. Since the SLE and IRL are situated in a subtropical area, it is affected by two major climatic seasons, dry (winter) and wet (summer). This contribution investigates the application of the AZTI's Marine Biotic Index (AMBI) and multivariate-AMBI (M-AMBI), to assess the ecological status of these estuaries. AMBI was firstly calculated after assigning most of the previously unassigned species to each of the five ecological groups (from sensitive to first order opportunistic species). Three main benthic assemblages, associated to oligohaline, meso-polyhaline and euhaline stretches, have been identified within the area. Reference conditions of richness, Shannon's diversity and AMBI have been derived for these assemblages; M-AMBI has then been calculated. Both methods show that the inner part of the SLE is affected by anthropogenic pressures (increased freshwater inflow, with elevated nutrient input, and sedimentation), whilst the IRL is less affected. We have demonstrated that AMBI and M-AMBI are insensitive to the dramatic seasonal changes occurring in the SLE/IRL. At some of the stations a significant positive trend in benthic quality has been identified, linked to the polluted freshwater discharges decrease. The use of both tools seems adequate in assessing benthic health in this subtropical area.     

Effect of ecological group classification schemes on performance of the AMBI benthic index in US coastal waters

The AZTI Marine Biotic Index (AMBI) requires less geographically-specific calibration than other benthic indices, but has not performed as well in US coastal waters as it has in the European waters for which it was originally developed. Here we examine the extent of improvement in index performance when the Ecological Group (EG) classifications on which AMBI is based are derived using local expertise. Twenty-three US benthic experts developed EG scores for each of three regions in the United States, as well as for the US as a whole. Index performance was then compared using: (1) EG scores specific to a region, (2) national EG scores, (3) national EG scores supplemented with standard international EG scores for taxa that the US experts were not able to make assignments, and (4) standard international EG scores. Performance of each scheme was evaluated by diagnosis of condition at pre-defined good/bad sites, concordance with existing local benthic indices, and independence from natural environmental gradients. The AMBI performed best when using the national EG assignments augmented with standard international EG values. The AMBI using this hybrid EG scheme performed well in differentiating apriori good and bad sites (>80% correct classification rate) and AMBI scores were both concordant and correlated (r_s = 0.4–0.7) with those of existing local indices. Nearly all of the results suggest that assigning the EG values in the framework of local biogeographic conditions produced a better-performing version of AMBI. The improved index performance, however, was tempered with apparent biases in score distribution. The AMBI, regardless of EG scheme, tended to compress ratings away from the extremes and toward the moderate condition and there was a bias with salinity, where high quality sites received increasingly poorer condition scores with decreasing salinity.     

Cancer incidence in the AGRICAN cohort study (2005–2011)

BackgroundNumerous studies have been conducted among farmers, but very few of them have involved large prospective cohorts, and few have included a significant proportion of women and farm workers. Our aim was to compare cancer incidence in the cohort (overall, by sex, and by work on farm, occupational status and pesticide use) within the general population.MethodsMore than 180,000 participants in the AGRICAN cohort were matched to cancer registries to identify cancer cases diagnosed from enrolment (2005–2007) to 31st December 2011. We calculated standardized incidence ratios (SIRs) and 95% confidence intervals (95%CIs).ResultsOver the period, 11,067 incident cancer cases were identified (7304 men and 3763 women). Overall cancer incidence did not differ between the cohort and the general population. Moreover, SIRs were significantly higher for prostate cancer (SIR = 1.07, 95%CI 1.03–1.11) and non-Hodgkin lymphoma (SIR = 1.09, 95%CI 1.01–1.18) among men, skin melanoma among women (SIR = 1.23, 95%CI 1.05–1.43) and multiple myeloma (men: SIR = 1.38, 95%CI 1.18–1.62; women: SIR = 1.26, 95%CI 1.02–1.54). In contrast, SIRs were lower for upper aerodigestive tract and respiratory cancers. Increase in risk was greater in male farm workers for prostate and lip cancer, in female farm workers for skin melanoma, and in male farm owners for multiple myeloma. Moreover, incidence of multiple myeloma and skin melanoma was higher among male and female pesticide users respectively.ConclusionWe found a decreased incidence for tobacco-related cancers and an increased incidence of prostate cancers, skin melanoma and multiple myeloma. Specific subgroups had a higher cancer incidence related to occupational status and pesticide use.     

The effects of cage volume and cage shape on the condition and behaviour of captive European starlings (Sturnus vulgaris)

Cage size is widely recognised as an important determinant of captive animal welfare, but in contrast, cage shape has received far less attention. Husbandry recommendations for flying birds state that cages should be long in shape because this allows greater potential for flight. However, so far no studies have investigated the impact of cage shape on the behaviour or welfare of captive flying birds. We measured the effects of cage size and shape on the condition and behaviour of captive wild-caught European starlings (Sturnus vulgaris) using a 2 × 3 factorial design in which birds were individually housed for 1 week in cages of one of two volumes (either medium at 0.3 m³ or large at 1 m³), and one of three shapes (long with an aspect ratio (i.e. length/height) of 3.43), standard with an aspect ratio of 1.72 or tall with an aspect ratio of 0.86). We found effects of cage size and the interaction of cage size and shape on the behaviour and condition of birds. In interpreting the welfare implications of our results we focused on stereotypic behaviour as measured by incidence of somersaulting and a novel statistic that quantifies sequential dependencies in the birds’ locations within the cage. The lowest measures of stereotypic behaviour were recorded in the large cages and the medium long cage. Cage shape was more important in determining the quantity of stereotypic behaviour in the medium cages than the large cages. Our findings support the recommendation that starlings be housed in long-shaped cages.     

Microbial–meiofaunal interrelationships in coastal sediments of the Red Sea

Population density and biomass of bacteria and meiofauna were investigated seasonally in the sediments of the north-western bank of Red Sea. Samples of sediments were collected seasonally from three different stations to determine microphytobenthic biomass (chlorophyll a), protein, lipid, carbohydrate, and total organic matter concentrations. These investigations revealed that microbial components tended to increase their dominancy, whereas sensitive meiofauna were extremely reduced during the entire study period. Thus a very low density of the total meiofauna (with an annual average of 109 ± 26 ind./10 cm²) was recorded whilst the benthic microbial population densities exhibited higher values (ranging from 0.31 ± 0.02 × 10⁸ to 43.67 ± 18.62 × 10⁸/g dry sediment). These changes in the relative importance analysis of benthic microbial components versus meiofaunal ones seem to be based on the impact of organic matter accumulation on the function and structure of these benthic communities. Proteins, lipids and carbohydrates showed very low concentration values, and the organic matter mostly consisted of carbohydrates, reflecting lower nutritional values for benthic fauna in general and meiofauna in particular. The distribution of microbial and meiofaunal communities seems to be dependent on the quality of the organic matter rather than on its quantity. Total organic matter concentrations varied between 5.8 and 7.6 mg/g, with organic carbon accounting for only 32% of the total organic matter. Chlorophyll a attained very low values, fluctuating between 0.11 and 0.56 μg/g, indicating the oligotrophy of the studied area. The very low concentration of chlorophyll a in the Red Sea sediment suggests that the sedimentary organic matter, heterotrophic bacteria and/or protozoa constitute an alternative resource that is consumed by meiofauna when algae are less abundant. Protozoa, therefore, represent the “missing link in bacteria–meiofauna interaction in the Red Sea marine sediment ecosystem.     

Temporal dynamics of benthic macroinvertebrate communities and their response to elevated specific conductance in Appalachian coalfield headwater streams

Coal mining in central Appalachia USA causes increased specific conductance in receiving streams. Researchers have examined benthic macroinvertebrate community structure in such streams using temporally discrete measurements of SC and benthic macroinvertebrates; however, both SC and benthic macroinvertebrate communities exhibit intra-annual variation. Twelve central Appalachian headwater streams with reference quality physical habitat and physicochemical conditions (except for elevated SC in eight streams) were sampled ≤fourteen times each between June 2011 and November 2012 to evaluate benthic macroinvertebrate community structure. Specific conductance was recorded at each sampling event and by in situ data loggers. Streams were classified by mean SC Level (Reference, 17–142 μS/cm; Medium, 262–648 μS/cm; and High, 756–1535 μS/cm). Benthic macroinvertebrate community structure was quantified using fifteen metrics selected to characterize community composition and presence of taxa from orders Ephemeroptera, Plecoptera, and Trichoptera. Metrics were analyzed for differences among SC Levels and months of sampling. Reference streams differed significantly from Medium-SC and High-SC streams for 11 metrics. Medium-SC streams had the most metrics exhibiting significant differences among months. Relative abundances of Plecoptera and Trichoptera were not sensitive to SC, as the families Leuctridae and Hydropsychidae exhibited increased relative abundance (vs. reference) in streams with elevated SC. In contrast, Ephemeroptera richness and relative abundance were lower, relative to reference, in elevated-SC streams despite increased relative abundance of Baetidae. Temporal variability was evident in several metrics due to influence by taxa with seasonal life cycles. These results demonstrate that benthic macroinvertebrate communities in elevated-SC streams are altered from reference condition, and that metrics differ in SC sensitivity. The time of year when samples are taken influenced measured levels and differences from reference condition for most metrics.     

Habitat selection by endangered Himalayan musk deer (Moschus chrysogaster) and impacts of livestock grazing in Nepal Himalaya: Implications for conservation

Habitat management within and outside protected areas is a key to effective conservation of wildlife. This is particularly vital for declining wildlife populations within the boundary of conservation areas, while sharing their potential habitat range with foraging livestock. In an effort to understand the habitat selection by Himalayan musk deer (Moschus chrysogaster) and explore any potential impacts of livestock grazing, we conducted the present study in a conservation area of central Nepal Himalaya. We recorded data on musk deer and livestock presence and absence (based on signs of fecal pellet, footprint, and resting site) along the elevational transect with associated topographic features (elevation, slope, aspect, distance to water, and vantage point distance) and vegetation features (tree spp., shrub spp., herb spp., and canopy-cover). Using logistic regression model we found that elevation, aspect, canopy-cover, and tree spp. in the area significantly affect the likelihood of habitat selection by musk deer. In particular, they selected the southern aspect of the area with elevation ≥ 3529 m, canopy-cover ≥ 42%, and with stands of Pinus spp. and Abies spp. Slope and canopy-cover significantly affected the foraging area selection by livestock. They selected the gentler slopes in the northern aspect of the area with altitude < 3529 m and canopy-cover < 42%. Also, presence of one group of herbivore (i.e. musk deer and livestock) was not found to affect the likelihood of habitat selection by the other group. These independent habitat selections are possibly the responses to morphological and behavioral adaptations than to impacts and interactions between these two groups of herbivores. We suggest to avoid any disturbances and livestock grazing on the area that disrupt the resources and conditions likely selected and occupied by musk deer population.     

Shape complexity of space used by American black bears influenced by sex and intensity of use

Disentangling the complexities that influence animal space use poses substantial challenges based on decision trade-offs and constraints imposed on animals. Optimal decisions suggest that the spatial complexity of home-range shapes should be inversely related to energy conservation and fitness. Hence, the most beneficial shape should be the circle. We evaluated whether shape complexity (i.e., an index of circularity) of home ranges was influenced by two extrinsic (spatial heterogeneity, preferred habitat [i.e., deciduous forest]), and three intrinsic (sex, season [breeding, non-breeding], intensity of use) factors, with intensity of use indexed as contours containing core and peripheral areas. We estimated utilization distributions of 39 radiomarked adult American black bears (Ursus americanus), a habitat generalist, using fixed-kernel techniques and estimated 50% (core area) and 95% (peripheral area) contours. We fit a set of 47 models using linear modeling and ranked models using small-sample Akaike Information Criterion. Coefficients for the best model were the intrinsic factors intensity of use (reference category = core; 0.118; 95% CL = 0.064–0.173), sex (reference = female; 0.105; 95% CL = 0.043–0.167), and intercept (0.229; 95% CL = 0.186–0.272). Shape complexity was less for core areas than peripheral areas and less for females than males. Considering complex resource selection patterns within a fragmented landscape, both sexes appeared to use energy-maximizing strategies, although the increase in shape complexity for males may be an allometric relationship based on size dimorphism. Our approach supported the phenomenon of optimality as manifested through home-range shape complexity, but we suggest that assessment of this phenomenon for habitat specialists may yield different results, including the potential importance of intrinsic factors based on more restrictive limiting factors.     

Assessing the suitability of five benthic indices for environmental health assessment in a large subtropical South American estuary

Despite the increased and widespread usage of benthic indices for environmental health assessment, some methodological ambiguities remain to be solved. We tested the congruence and consistency of the benthic indices ITI, BO2A, BENTIX, AMBI and M-AMBI in a subtropical estuary (Paranaguá Bay, Brazil). Indices were applied to non-vegetated tidal flats increasingly contaminated by sewage to test: (i) correlations with molecular biomarkers of sewage (consistency); and (ii) evaluate the overall agreement/similarity of responses (congruence). The responses of the benthic indexes ITI, AMBI and BO2A were congruent among themselves and consistent with molecular biomarkers values. BENTIX and M-AMBI were less consistent and congruent and possibly need a readjustment of boundaries for subtropical habitats. The indices seemed robust to natural background yearly variations not related to contamination. Faecal sterols associated to nutrient contents suitably supported the validation of indices and could integrate reference conditions for sewage impacted coastal habitats. Benthic indices can successfully integrate management guidelines, but their suitable application demands further research on tolerance shifts of key indicator species.     

Availability and utilization of waste fish feed by mussels Mytilus edulis in a commercial integrated multi-trophic aquaculture (IMTA) system: A multi-indicator assessment approach

Fish feed waste enhancement of the particulate food supply and performance of mussels Mytilus edulis suspended near salmon cages at an integrated multi-trophic aquaculture (IMTA) site was assessed using a multi-indicator approach. Dietary indicators included bulk measurements of seston quantity and nutritional quality, proximate analysis (PA), fatty acid (FA) and stable isotope (SI) composition. Mussel tissue indicators consisted of PA and FA composition. Mussel performance was assessed from physiological integrations (scope for growth, SFG), growth efficiency (K₂) and condition index (CI). All measurements were made over 2 days at a commercial IMTA farm and a monoculture mussel farm in the Bay of Fundy (Canada). Significant differences detected in seston quantity and quality were within the range of natural spatial variability. The SFG of IMTA mussels was lower (28.71 J h⁻¹) than monoculture mussels (38.71 J h⁻¹) and reflected site differences in natural food availability and composition that affected absorption rate. PA of mussel organs didn't reflect a significant fish feed contribution to the mussel diet. However, dietary enhancement and assimilation of fish feed waste was demonstrated by significantly higher levels of feed FA biomarkers 20:1ω9, 18:2ω6, 18:1ω9 and low ω3/ω6 ratio in seston, mussel tissues and feces at the IMTA site than at the mussel farm. SI (δ¹³C and δ¹⁵N) in seston and mussel feces significantly differed among sites and IMTA mussels had significantly higher CI (21%) than monoculture individuals (16%). It was concluded that bulk indicators of the diet, short-term physiological integrations, and PA of mussel tissues have a limited capacity to detect dietary enhancement at IMTA sites. FA and SI tracers of fish feed waste were shown to be more sensitive for detecting the low-levels of diet enhancement within the large range of natural seston variation.     

Genetic structure of Octopus vulgaris (Cephalopoda,Octopodidae) in the central Mediterranean Sea inferred from the mitochondrial COIII gene

The polymorphism of the mitochondrial gene cytochrome oxidase III was studied in the Mediterranean octopus, Octopus vulgaris Cuvier, 1797. A total of 202 specimens from seven sampling sites were analysed with the aim of elucidating patterns of genetic structure in the central Mediterranean Sea and to give an insight into the phylogeny of the Octopus genus. Phylogenetic analyses showed that individuals from the central Mediterranean belong to the O. vulgaris species whose limits should nevertheless be clarified. Concerning genetic structure, two high-frequency haplotypes were present in all locations. The overall genetic divergence (Φ_ST = 0.05, P < 0.05) indicated a significant genetic structuring in the study area and an AMOVA highlighted a significant break between western and eastern Mediterranean basins (Φ_CT = 0.094, P < 0.05). Possible explanations for the observed patterns of genetic structuring are discussed with reference to their relevance for fisheries management.     

The use of spatial ecological modelling as a tool for improving the assessment of geographic range size of threatened species

We analysed endemic threatened tree and reptile species of Socotra Island (Yemen), characterised by different ecological requirements and spatial distribution, in order to evaluate the usefulness of spatial ecological modelling in the estimation of species extent of occurrence (EOO) and area of occupancy (AOO). Point occurrences for the entire species range were used to model their spatial distribution by Random Forest (RF) and Generalised Linear Model (GLM). For each species the suitability area (SA) was obtained by applying the 0% omission error criterion on the probability map, and compared or integrated with EOO and AOO area obtained by topological methods such as the minimum convex polygon (MCP), α-hull and 2 km × 2 km grid.RF showed a lower prediction error than GLM. Higher accuracy was achieved for species with higher number of occurrences and narrower ecological niche. SA was always greater than AOO measured with the 2 km × 2 km grid method. SA was greater than EOO, measured by both MCP and α-hull methods, for species with localised distribution, while it was smaller for widely distributed species. EOO-α-hull area was equal or smaller than that calculated by MCP depending on the spatial distribution of species. AOO measured considering the SA within the EOO-MCP was greater than that measured using the standard 2 km × 2 km grid. Conversely, AOO calculated considering the suitable area within the EOO-α-hull showed variable results, being smaller or greater than the 2 km × 2 km grid AOO depending on the ecological niche and spatial distribution of species. According to our results, SEM does not provide an effective alternative to topological methods for the estimate of EOO and AOO. However, it may be considered a useful tool to estimate AOO within the boundaries of EOO measured by the α-hull method, because it reduces some potential sources of inconsistency and bias.     

Use of tolerance values to diagnose water-quality stressors to aquatic biota in New England streams

Identification of stressors related to biological impairment is critical to biological assessments. We applied nationally derived tolerance indicator values for four water-quality variables to fish and benthic macroinvertebrate assemblages at 29 sites along an urban gradient in New England. Tolerance indicator values (TIVs), as biologically based predictors of water-quality variables, were determined for dissolved oxygen, nitrite plus nitrate (nitrate), total phosphorus, and water temperature for each site based on observed biological assemblages (TIV_O), and for expected assemblages (TIV_E). The quotient method, based on a ratio of the TIVs for observed and expected assemblages (tolerance units), was used to diagnose potential water-quality stressors. In addition, the ratio of measured water-quality values to water-quality criteria (water-quality units) was calculated for each water-quality variable to assess measured water-quality stressors. Results from a RIVPACS predictive model for benthic macroinvertebrates and Bray-Curtis dissimilarity for fish were used to classify sites into categories of good or impaired ecological condition. Significant differences were detected between good and impaired sites for all biological tolerance units (fish and benthic macroinvertebrate assemblages averaged) except for nitrate (P = 0.480), and for all water-quality units except for nitrate (P = 0.183). Diagnosis of water-quality stressors at selected sites was, in general, consistent with State-reported causes of impairment. Tolerance units for benthic macroinvertebrate and fish assemblages were significantly correlated for water temperature (P = 0.001, r = 0.63), dissolved oxygen (P = 0.001, r = 0.61), and total phosphorus (P = 0.001, r = 0.61), but not for nitrate (P = 0.059, r = −0.35). Differences between the two assemblages in site-specific diagnosis of water-quality stressors may be the result of differences in nitrate tolerance.     

莱州湾小清河口近岸海域底栖生境健康评价

于2019年7月、8月和9月对莱州湾小清河口近岸海域的大型底栖动物进行调查，对该海域大型底栖动物群落的种类组成和群落结构等进行研究，利用丰度/生物量比较曲线法、AMBI指数法和M-AMBI指数法对研究海域大型底栖动物群落健康和底栖生境健康状况进行评价。研究结果表明，2019年7月、8月和9月共采集到大型底栖动物64种，其中多毛类24种，甲壳类19种，软体动物17种，其他类群4种。该海域的优势种为光滑河蓝蛤（Potamocorbula laevis）、彩虹明樱蛤（Moerella iridescens）、半褶织纹螺（Nassarius semiplicatus）、四角蛤蜊（Mactra veneriformis），寡鳃齿吻沙蚕（Nephthys oligobranchia）、中蚓虫（Mediomastus californiensis）、东方长眼虾（Ogyrides orientalis）、尖齿拳蟹（Philyra acutidens）和短角双眼钩虾（Ampelisca brevicornis），其中彩虹明樱蛤和寡鳃齿吻沙蚕在三次调查中均为优势物种，优势度明显。群落结构聚类分析和多维尺度分析表明，7月研究海域的大型底栖动物群落以10%的相似性可以分为3组，8月以18%相似性可以分为4组，9月以19%的相似性可以分为3组，三次调查的群落结构相似度均较低。丰度/生物量比较曲线法研究结果显示，底栖动物群落生物量优势显著，群落处于未干扰状态。AMBI指数及M-AMBI指数分析结果表明，莱州湾小清河口近岸海域底栖生境处于未干扰或者轻度干扰的状态，健康状况处于高等或者优良的状态。     

Relocation of dredged material in estuaries under the aspect of the Water Framework Directive—A comparison of benthic quality indicators at dumping areas in the Elbe estuary

In the context of the requirements of the European Water Framework Directive (WFD) numerous benthic indices have been proposed recently to assess the ecological quality of marine and transitional waters. In several studies these metrics were applied to coastal and estuarine environments under diverse anthropogenic pressures. Although currently the dumping of dredged material is one of the most prominent human impacts that modify estuaries, the performance of benthic indices to detect effects of dredged sediment relocation has not yet been tested explicitly. Hence we examined a selection of common metrics (species richness, Shannon diversity, AMBI, M-AMBI, W-value, BO2A) at 11 dumping and 11 nearby reference areas in the highly modified Elbe estuary (Germany), where permanent dredging is necessary to maintain the depth of the navigation channel. In order to cover the entire estuary, the study area spanned over the whole salinity gradient from limnic to euhaline. Additionally, we investigated changes in benthic communities due to dredged material placement. All indices, except the W-value, were suitable to differentiate between dumping and reference areas and showed significantly better index values exclusively at reference areas. The applicability of AMBI and M-AMBI was restricted in the limnic stretch due to the more frequent occurrence of freshwater species there. The W-value and BO2A were non-satisfactory in the case of azoic sediment, and in most cases these two indices indicated much better ecological status classifications than the other indices tested. Furthermore, the BO2A had restricted applicability with increasing salinity. At eight of eleven sites the benthic communities differed significantly between dumping and reference areas. Our findings show that the power of conventional benthic indices to detect physical disturbances like the dumping of dredged sediment varies greatly. Having this in mind, we suggest to choose carefully the benthic indices for ecological quality assessments according to the WFD in estuaries in order to avoid misclassifications. Such errors may lead to unnecessarily expensive remediation activities or, in the opposite case, to inactivity although actions were necessary. Furthermore, in order to better meet the WFD requirements we suggest that, regarding frequency and volume, dumping should be adapted as far as possible to the natural processes of sediment movement.     

Magnesium and strontium compositions of recent symbiont-bearing benthic foraminifera

Minor and trace elements in foraminiferal carbonates are potential paleo-proxies of climate, nutrient and seawater composition. There are very few reports of trace element composition of symbiont-bearing, larger foraminifera that are known to be important constituents of shallow-marine, modern and ancient carbonates. In this paper we examine the range of variation in Mg and Sr content of Recent species of these foraminifera from a lagoon of Lakshadweep Atoll (Indian Ocean) and Akajima Islands, Japan. Two hyaline species, Amphistegina lessonii and Neorotalia calcar,and two porcellaneous species, Amphisorus hemprichii and Marginopora vertebralis were collected live from Lakshadweep islands. Mg / Ca in these foraminifera is of an order of magnitude higher than the values reported for planktonic and symbiont-free benthic foraminifera. The Sr / Ca values are, however, comparable with the reported values in other foraminiferal taxa and they are found to vary within a narrow range. Electron-probe micro-analysis of three symbiont-bearing benthic species indicates spatial heterogeneity of high orders in Mg / Ca composition in all the species. The annual variation in temperature and pH of the lagoon water cannot explain the observed amplitude of the compositional variation. The photosynthesis and respiration of the symbionts and host foraminifera are possibly the major cause of compositional heterogeneity in individual tests, as has also been recently postulated for symbiont-bearing planktonic foraminiferal species. It highlights the need to isolate biological factors and necessitates species-specific paleotemperature scale in paleoclimatic analysis. We also analyzed δ¹⁸O, δ¹³C, Ca, Mg and Sr in carefully dissected chambers of a reef-dwelling, porcellaneous benthic foraminifer, Marginopora kudakajimaensis, collected live in four seasons. A moderate positive correlation is observed between Mg / Ca and temperature. However, large inter- and intra-test variation in Mg limits the precision of Mg / Ca as palaeotemperature proxy. The Sr / Ca of the test calcite is unrelated to temperature of the sea water. The δ¹³C of M. kudakajimaensis does not correlate with δ¹⁸O, Mg / Ca or Sr / Ca.     

Structure and water permeability of fully hydrated diphytanoylPC

Diphytanoylphosphatidylcholine (DPhyPC) is a branched chain lipid often used for model membrane studies, including peptide/lipid interactions, ion channels and lipid rafts. This work reports results of volume measurements, water permeability measurements P_f, X-ray scattering from oriented samples, and X-ray and neutron scattering from unilamellar vesicles at T = 30 °C. We measured the volume/lipid V_L = 1426 ± 1 Å³. The area/lipid was found to be 80.5 ± 1.5 Å² when both X-ray and neutron data were combined with the SDP model analysis (Ku?erka, N., Nagle, J.F., Sachs, J.N., Feller, S.E., Pencer, J., Jackson, A., Katsaras, J., 2008. Lipid bilayer structure determined by the simultaneous analysis of neutron and X-ray scattering data. Biophys. J. 95, 2356–2367); this is substantially larger than the area of DOPC which has the largest area of the common linear chain lipids. P_f was measured to be (7.0 ± 1.0) × 10^?3 cm/s; this is considerably smaller than predicted by the recently proposed 3-slab model (Nagle, J.F., Mathai, J.C., Zeidel, M.L., Tristram-Nagle, S., 2008. Theory of passive permeability through lipid bilayers. J. Gen. Physiol. 131, 77–85). This disagreement can be understood if there is a diminished diffusion coefficient in the hydrocarbon core of DPhyPC and that is supported by previous molecular dynamics simulations (Shinoda, W., Mikami, M., Baba, T., Hato, M., 2004. Molecular dynamics study on the effects of chain branching on the physical properties of lipid bilayers. 2. Permeability. J. Phys. Chem. B 108, 9346–9356). While the DPhyPC head–head thickness (D_HH = 36.4 Å), and Hamaker parameter (H = 4.5 × 10^?21 J) were similar to the linear chain lipid DOPC, the bending modulus (K_C = 5.2 ± 0.5 × 10^?21 J) was 30% smaller. Our results suggest that, from the biophysical perspective, DPhyPC belongs to a different family of lipids than phosphatidylcholines that have linear chain hydrocarbon chains.