Ecological Status Of Coastal Waters Research Articles

Land-use and agriculture in Denmark around year 1900 and the quest for EU Water Framework Directive reference conditions in coastal waters

The EU Water Framework Directive (WFD) aims to protect the ecological status of coastal waters. To establish acceptable boundaries between good and moderate ecological status, the WFD calls for reference conditions practically undisturbed by human impact. For Denmark, the nitrogen (N) concentrations present around year 1900 have been suggested to represent reference conditions. As the N load of coastal waters relates closely to runoff from land, any reduction in load links to agricultural activity. We challenge the current use of historical N balances to establish WFD reference conditions and initiate an alternative approach based on parish-level land-use statistics collected 1896/1900 and N concentrations in root zone percolates from experiments with year 1900-relevant management. This approach may be more widely applicable for landscapes with detailed historic information on agricultural activity. Using this approach, we find an average N concentration in root zone percolates that is close to that of current agriculture. Thus, considering Danish coastal waters to be practically unaffected by human activity around year 1900 remains futile as 75% of the land area was subject to agricultural activity with a substantial potential for N loss to the environment. It appears unlikely that the ecological state of coastal waters around year 1900 may serve as WFD reference condition.

Cartography of littoral rocky-shore communities to assess the ecological status of water bodies through the application of CARLIT method in Algeria (South-Western Mediterranean Sea)

The cartography of shallow water macroalgal assemblages allows the assessment of water quality in coastal water bodies through the application of CARLIT. In this study, we have applied CARLIT to assess the ecological status of Algerian coastal water bodies for the first time. The surveyed zone is still in a good ecological status since 52% have a good to a high ecological Status. CARLIT index is well correlated with anthropogenic pressures and has proved suitable for the evaluation of the ecological status of coastal waters. Comparison between EQR values and EEI-c shows a similar pattern of change. CARLIT method allowed the collection of accurate information on the distribution and abundance of shallow-water communities. We also provide a cartographic baseline of the coastal assemblages useful for further evaluations on their geographic extension and for the implementation of a monitoring project on water quality in Algerian coast.

Evaluating the coastal ecosystem status of two Western and Eastern Mediterranean islands using the seagrass Posidonia oceanica

Abstract Mediterranean seagrass Posidonia oceanica is used as a ‘biological quality element’ in the long-term monitoring programmes of the Water Framework Directive (WFD 2000/60/EC) for the evaluation of ecological status of coastal waters. Due to its low resilience to anthropogenic pressures, P. oceanica meadows have disappeared irreversibly along some of the Mediterranean coasts. The main objective of this survey, is therefore to compare the ecological status of coastal waters and P. oceanica meadows in two islands from Eastern (Gokceada, Turkey) and Western (Corsica, France) Mediterranean Sea based on the Posidonia Biotic Index (BiPo) and the Vitality Index besides concentrating on: (i) their consistency in different environmental conditions present in the Mediterranean Sea, (ii) their effectiveness to discriminate the ecological status of coastal waters in relation to different anthropogenic pressures and (iii) their application capacity to initiate long-term data series for monitoring the evolution of the meadows in less evaluated regions (i.e. from the Eastern Mediterranean). The measurements of several descriptors of P. oceanica are interpreted based on the BiPo and the Vitality indices for 2 regions; 9 sites from Gokceada and 15 sites from Corsica exposed to different human pressures. The mean BiPo and Vitality indices are higher in Corsica than in Gokceada, where the values correspond to a “good” status for Corsica and a “moderate” status in Gokceada. The application of these biotic indices showed their feasibility and comparability to assess the ecological status in different environmental conditions. Significant relationships between the scores of Anthropization index and the EQR values of the BiPo index (r = −0.745, p

Cystoseira baccata meadows along the French Basque coast (Bay of Biscay) as a reference for the implementation of the Water Framework and Marine Strategy EU directives

Cystoseira baccata, a biological quality element for the implementation of the Water Framework and Marine Strategy EU Directives, is a dominant species in the subtidal rocky bottoms of the Basque coast. As part of this issue and given the need to better understand the functional character of benthic rocky ecosystems and use them as a reference to anthropogenic changes, two samplings campaigns were conducted in 2014 and 2017. Several population parameters (i.e. frond density, frond length frond-length/total frond-length ratio and taxonomic richness of epibionts) of C. baccata were studied from three sites monitored within the Water Directive Framework in relation to bathymetry during the two campaigns. The results showed a significant influence of bathymetry on frond density, frond length and the epibiotic load, and also an effect of sampling time for the seaweed and epibionts (epiflora and epifauna). The characterization of these functional population parameters for C. baccata under natural conditions are extremely valuable for its application to monitoring programs evaluating the ecological status of coastal waters in this region.

Using Zostera noltei biometrics for evaluation of the ecological and environmental quality status of Black Sea coastal waters

A wide range of seagrass biometrics as well as environmental variables are currently used for classification of the ecological status of coastal water bodies in accordance with the Water Framework Directive (WFD). The use of extensive sets of indicators provides a satisfactory assessment of environmental quality statuses, but also requires substantial amounts of additional laboratory efforts and costs. In this study, typical population-level and individual biometrics of the dwarf eelgrass Zostera noltei (Hornem.) (shoot density, total biomass, above- and belowground biomass, above- to belowground biomass ratio, leaf length and leaf area) were tested and used in the adaptation and validation of a simplified, easy to apply and cost-effective pollution index (ZnoPI) for evaluation of the ecological and environmental quality status of Black Sea coastal waters in accordance with the WFD and the Marine Strategy Framework Directive (MSFD) criteria. Based on the metrics tested, reference conditions were established and ecological quality ratios (EQR) of the studied areas were calculated. The index validation was based on biological sampling and environmental monitoring of Z. noltei meadows in a variety of ecological conditions along the Southern Black Sea coast of Bulgaria. The environmental condition of the study sites was evaluated with an Integrated Pollution Status (I.P.S.), which combined water column variables (nutrients, chlorophyll-a, suspended particulate matter, transparency) as well as total organic matter content and concentrations of heavy metals in sediments in a single metric. Significant correlation between ZnoPI EQR values and I.P.S. was found (r = 0.917 p < 0.0001), which validated the index for Bulgarian Black Sea coastal waters, and possibly other areas with similar environmental conditions.

Determination of risk factors for herpesvirus outbreak in oysters using a broad-scale spatial epidemiology framework

Marine diseases have major impacts on ecosystems and economic consequences for aquaculture and fisheries. Understanding origin, spread and risk factors of disease is crucial for management, but data in the ocean are limited compared to the terrestrial environment. Here we investigated how the marine environment drives the spread of viral disease outbreak affecting The Pacific oyster worldwide by using a spatial epidemiology framework. We collected environmental and oyster health data at 46 sites spread over an area of 300 km2 along an inshore-offshore gradient during an epizootic event and conducted risk analysis. We found that disease broke out in the intertidal farming area and spread seaward. Mortalities and virus detection were observed in oysters placed 2 km from the farming areas, but oysters of almost all sites were subclinically infected. Increasing food quantity and quality, growth rate and energy reserves of oyster were associated with a lower risk of mortality offshore whereas increasing turbidity, a proxy of the concentration of suspended particulate matter, and terrestrial inputs, inferred from fatty acid composition of oysters, were associated with a higher risk of mortality. Offshore farming and maintenance of good ecological status of coastal waters are options to limit disease risk in oysters.

Effectiveness of Posidonia oceanica biotic indices for assessing the ecological status of coastal waters in Saronikos Gulf (Aegean Sea, Eastern Mediterranean)

Biotic indices are considered key assessment tools in most national and European policies aimed at improving the quality of coastal waters. At present, several Water Framework Directive (WFD)-compliant biotic indices based on the marine angiosperm Posidonia oceanica have been developed and applied in the Mediterranean Sea. In this study, we investigated the effectiveness of four different P. oceanica indices (POMI, PREI, Valencian CS, and BiPo) in evaluating the ecological status of coastal waters in a case study area of Greece. The evaluation, comparison, and validation of the Ecological Status Class (ESC) assessments obtained by each index were based on a set of eight common sites that encompasses the maximum range of environmental quality in the study area. Four sampling sites separated by tens of km were chosen in each of the two water bodies (WBs) studied. The spatial variations of the features of P. oceanica meadows were examined according to a hierarchical sampling design across four spatial scales, ranging from metres to tens of km, using independent nested analysis of variance. Except for the BiPo index, the reference values for each metric/index were defined by the dataset available for the study area. All biotic indices classified the WBs of the study area in Good ESC category. Only three of the four indices (PREI, Valencian CS, and BiPo) showed high comparability in the assessment of ESC at study site level. It is assumed that the differences found in the remaining index (POMI) are due to the different type of metrics taken into consideration and the different weighting given to them. Our findings suggest that all indices can provide an overall view of the cumulative impact of multiple environmental stressors existing in the study area, and can thus help raise awareness of ecosystem degradation.

Ecological status of coastal waters of Ayvalık (Aegean Sea, Turkey) assessed by the EEI method

Macroalgae and angiosperms are proposed as biological elements to assess the ecological status of coastal waters and transitional systems by the EU Water Framework Directive. Recently, the Ecological Evaluation Index (EEI) was intercalibrated in the Mediterranean eco-region by the Mediterranean Geographic Intercalibration Group (MEDGIG). In the present paper, the EEI was tested at two different localities, the inner and outer bays of the city Ayvalik located on the Aegean coast of Turkey. The study shows a high ecological quality for the outer bay, whereas, the inner bay is of moderate quality.

Towards a suitable ecological status assessment of highly stratified mediterranean estuaries: A comparison of benthic invertebrate fauna indices

Biotic indices developed to assess the ecological status of coastal waters according to the European Water Framework Directive (WFD) often show discrepancies when they are applied in transitional environments. Although several indices have been widely used in transitional waters throughout Europe, there is still a lack of knowledge about their suitability assessing ecological status. We evaluated the performance of most common used biotic indices and community parameters (e.g. Multivariate AZTI's Marine Biotic Index (M-AMBI), BENTIX, Benthic Opportunistic Polychaetes Amphipods index (BOPA), diversity indices, species richness, abundance) that have been proposed in the scope of WFD, using data of macroinvertebrate community coming from a special case of transitional water body, the highly stratified Ebro estuary. Additionally, we tested their ability to respond to the main pressures affecting the Ebro estuary, the hydrological alteration due to regulation and the pollution pressure due to nutrient enrichment. Estimation of hydrological alteration was based on flow historical data (period from 1913 to 1963), that we assumed as 'hydrological reference conditions' for Ebro estuary. Pollution pressure was estimated by means of PCA analysis including organic and nutrient enrichment related variables, expressed as a synthetic index by PCA factor scores extraction. All the community parameters were able to detect changes in macrofauna composition along the estuarine gradients and were able to differentiate between the impoverished stations and the healthier ones. Regarding indices, the ratings were contradictory and only M-AMBI classified the stations in the correct way. Strong significant correlations were found between indices and metrics and the calculated pressures; nevertheless, these correlations showed a paradoxical result, since increasing hydrological alteration benefited the macrofauna, achieving great complexity. Other identified limitations of biotic indices were the opposite classifications, overestimation of ecological status and low resolution ability. We conclude that for transitional water ecosystems, where each water body has particular characteristics, is difficult the use of 'common biological' assessment tools as the results of this study, among others (more details in discussion section), have demonstrated. Nevertheless, M-AMBI seemed to work in the correct way, so further investigation about its use for transitional waters is necessary. The development of new strategies such as the use of historical data, the use of metrics as a complement for the assessment could be a reliable alternative.

Testing and development of different metrics and indexes describing submerged aquatic vegetation for the assessment of the ecological status of semi-enclosed coastal water bodies in the NE Baltic Sea

A national assessment system for the classification of the ecological status of coastal waters according to the requirements of the EU Water Framework Directive was established in Estonia in the year 2007. The Estonian Phytobenthos Index was used to assess the ecological status of coastal waters based on submerged aquatic vegetation. After the testing period it appeared that the selected method did not respond to anthropogenic pressure in two national water types: the Vainameri and Parnu Bay. During this study new indexes were developed and validated against pressure for these areas. The PCF index was combined from the proportion of perennial species, charophytes, and Fucus spp. This index is suitable for the assessment of the ecological status in the Vainameri area. In Parnu Bay the depth distribution of higher plants and the proportion of opportunistic species showed the strongest correlation with eutrophication variables. These metrics were combined into the HPO index. The class boundaries for assessing the ecological status of water quality were determined for both indexes. The paper describes the calculation of the indexes.

Evaluating the impact of nutrient abatement measures on the ecological status of coastal waters: a Bayesian network for decision analysis

Environmental managers must make decisions about complex problems that have a high degree of uncertainty such as, which nutrient abatement measure optimally improves the condition of an ecosystem. Although data and models that provide information on this subject exist, their knowledge may be fragmentary and difficult to interpret. We present a user-friendly modelling tool that integrates results of different models and data-analyses. It can be used by decision-makers for assessing the probabilities of different nutrient abatement scenarios for achieving specific targets set by the Water Framework Directive for Finnish coastal waters in the Gulf of Finland. The results suggest that significant reductions in nutrient loads are required to achieve good ecological status in Finnish coastal waters, and in the event of increased precipitation these targets may be less likely to be attained. Moreover, different approaches to the status classification lead to very different conclusions.

Comparison of two indices based on macrophyte assemblages to assess the ecological status of coastal waters in the transition between the Atlantic and Mediterranean eco-regions

Several indices based on the composition and abundance of aquatic flora have been developed to assess the ecological status of coastal waters along the European coasts in the context of the Water Framework Directive. This directive pointed out the intercalibration of indices based on the same biological element within an eco-region to ensure the consistency and comparability among them. For a better management of coastal areas in the transition zone between two eco-regions, the comparison of indices developed for each eco-region may also be necessary. The aim of this work was to compare two indices based on macrophytes that have been proposed for two different and adjoining eco-regions: the RSL (Reduced Species List) in the Atlantic eco-region and the CARLIT (Cartography of littoral and upper sublittoral communities) in the Mediterranean. These indices were applied in 14 sites in the transition between the Atlantic Ocean and the Mediterranean Sea, where a wide range of anthropogenic pressures can be found, from high (Algeciras Bay) to almost negligible ("El Estrecho" Natural Park). Overall, both indices were sensitive to anthropogenic pressures and suitable to assess the ecological status. The comparison between indices suggested a bias in the assessment of the ecological status between good and high classes due to a different definition of high ecological status class between RSL and CARLIT. In addition, the most important disagreements between indices were found in the most degraded localities. The results showed, however, a high comparability between RSL and CARLIT despite their marked conceptual and methodological differences.

Application of landscape mosaics for the assessment of subtidal macroalgae communities using the CFR index

The assessment of anthropogenic impacts and ecological status of coastal waters is an important task to accomplish under the European Water Framework Directive (WFD 2000/60/EEC). Macroalgae are one of the biological quality elements that must be considered, but their assessment has been generally limited to intertidal areas due to the difficulties and costs associated with working in subtidal areas. In this work, the suitability of using landscape mosaicing techniques is analyzed for the application of the “Quality of Rocky Bottoms” index (CFR by its Spanish acronym) in subtidal areas. For this purpose, the sensitivity and accuracy of both the indicators that compose the CFR index (characteristic macroalgae coverage, fraction of opportunistics and characteristic macroalgae richness) and the index itself were tested against different sampling surfaces and validated through direct applications of the CFR carried out in situ by scuba divers. The study was carried out at three sites, located on the coast of Cantabria (N. Spain), covering a variety of environmental conditions (depth ranges and anthropogenic pressures). Underwater video transects of 5–20m length were recorded by scuba divers and processed with specialized software to build continuous image mosaics of the assessment sites. Each mosaic was inserted into a Geographical Information System where all distinguishable macroalgal species were identified and their coverages were estimated. Replicated subsamples of different areas (0.25m2, 0.5m2, 1m2 and 2.5m2) were tested from each mosaic for the estimation of both the single indicators and the CFR index itself. Main results showed that larger subsample areas produced higher and more accurate CFR values, mainly related to higher srichness values and to smaller variability within the replicates. Accordingly, the minimum sample size required to carry out this type of studies was estimated to be of 2.5m2, showing no significant differences with the total mosaics. At this spatial scale, the assessments of the CFR index using mosaics showed a significant correlation and an excellent agreement with the results obtained in situ. In summary, underwater video mosaicing techniques proved to be a useful tool for the application of the CFR index and could also be of great interest for the study of subtidal environments by allowing visualization of extensive seafloor areas.

Assessing the benthic ecological status in the stressed coastal waters of Yantai, Yellow Sea, using AMBI and M-AMBI

The coastal waters around Yantai have been subjected to a variety of anthropogenic pressures over the last two decades. To assess the current benthic ecological health and the recovery process of the benthic ecosystem, four surveys were conducted in 2010 and 2011. The AMBI and M-AMBI were applied to assess the benthic ecological status. The ecological status of the Sishili Bay and Taozi Bay was “moderate” to “good” at most sampling stations during four surveys, but some stations were degraded due to pollution and eutrophication induced by human activities. The ecological status improved after removal of the marine raft culture and minimizing the amount of waste water discharged into the coastal waters of Yantai. The AMBI and M-AMBI could be used as suitable bio-indicator indices to assess the benthic ecological status of coastal waters in Yantai, Shandong Province.

Complex monitoring of the state of sea water basins by optical methods. Part 3. Recording of dynamic processes by slicks on the sea surface

This is the third in a series of papers devoted to the development of instruments and techniques for rapid and complex analysis of the ecological status of coastal waters by optical methods. Capabilities of shore-based optical systems to map and determine the dynamic characteristics of ocean eddies and internal waves are shown. The efficiency of the maximum cross correlation method for retrieving the flow velocity field in the vortex body and the phase velocities of internal waves from optical images of the sea surface is discussed.

Ecological status of seagrass ecosystems: An uncertainty analysis of the meadow classification based on the Posidonia oceanica multivariate index (POMI)

Quantifying the uncertainty associated with monitoring protocols is essential to prevent the misclassification of ecological status and to improve sampling design. We assessed the Posidonia oceanica multivariate index (POMI) bio-monitoring program for its robustness in classifying the ecological status of coastal waters within the Water Framework Directive. We used a 7-year data set covering 30 sites along 500km of the Catalonian coastline to examine which version of POMI (14 or 9 metrics) maximises precision in classifying the ecological status of meadows. Five factors (zones within a site, sites within a water body, depth, years and surveyors) that potentially generate classification uncertainty were examined in detail. Of these, depth was a major source of uncertainty, while all the remaining spatial and temporal factors displayed low variability. POMI 9 matched POMI 14 in all factors, and could effectively replace it in future monitoring programs.

Macrophytobenthos and the ecological status of coastal waters around Sicily

This article gives a picture of recent studies on the phytobenthos of Sicily, paying particular attention to research carried out in the last 10–15 years. Twenty new taxa have been described from Sicily, and floristic studies have recorded 823 taxa at the specific and infraspecific levels. Vegetational studies have been used to verify changes that have possibly occurred in Sicilian areas over the last 30 years. Particular attention was also paid to 22 taxa considered to have been introduced into the Mediterranean Sea and which are found along the Sicilian coast. Applied research dealt mainly with management of the territory, promotion of a sustainable development model for the coastal zone, and using macroalgal communities to assess the quality of Sicilian waters. Finally, some suggestions for studies that should be carried out to increase phytobenthic knowledge of Sicilian coastal waters are made.

Knowledge discovering for coastal waters classification

Since almost all anthropogenic activities ultimately affect the coastal waters, access properties and processes in this environment is the major issue in decision making and system management. Particularly, seasonal patterns are not clear in tropical areas, therefore, requiring environmental classification. The knowledge of long-term biogenic element dynamics, the biological response, and the selection of indicators connecting lower and higher trophic levels have became a real need for the sustainable management of marine resources. Under this scenario, this paper uses a machine-learning approach to determine the ecological status of coastal waters based on patterns of occurrence of meroplankton larvae of epibenthic fauna and its relationship with other environmental variables. The case studied is the upwelling influenced bay at Cabo Frio Island (Rio de Janeiro – Brazil) because this location has been suffering with anthropogenic impact. Models of crisp and fuzzy rules have been tested as classifiers. Results show it is possible to access hidden patterns of water masses within a set of association rules.

Towards a better assessment of the ecological status of coastal waters using satellite-derived chlorophyll-a concentrations

The application of the new Water Framework Directive (WFD) of the European Union will require a dense and frequent monitoring of chlorophyll-a near the coast. Not counting the transitional water bodies located in the vicinity of estuaries, not less than seventy four coastal water bodies have to be monitored along the coast of the French Atlantic continental shelf and the English Channel. All the available data have to be gathered to implement a comprehensive monitoring scheme. To this purpose, we evaluate the capacity of ocean colour imagery to complete the conventional in situ data set collected in coastal networks. Satellite-derived chlorophyll-a concentration is obtained by the application of a coastal Look-Up-Table to water-leaving radiance of the Sea-viewing Wide Field Instrument Sensor (SeaWiFS) for the 1998–2004 period. Seven years of satellite-derived and in situ chlorophyll-a concentrations are compared at seven representative stations of different water bodies. These comparisons show that the satellite products are reliable in most of the situations studied and throughout the seasons. Then the satellite imagery is used to classify the coastal waters following the eutrophication risk criterion of the WFD. This classification is made according to the percentile-90 of chlorophyll-a calculated during the productive season, from March to October. Despite a lack of sensor coverage over a small fraction of the near shore waters, this work shows that the satellite monitoring can considerably ease the application of the WFD.

Assessment of the ecological status of north‐eastern Adriatic coastal waters (Istria, Croatia) using macroalgal assemblages for the European Union Water Framework Directive

Abstract Based on the inclusion of macroalgae in the European Union Water Framework Directive as quality elements for the evaluation of the ecological status of coastal waters, the suitability of one (Ecological Evaluation Index, EEI) of several previously proposed evaluation methods in the particular ecological conditions of the northern Adriatic Sea was tested. The EEI was assessed for 10 locations (polluted and putatively pristine) scattered along 60 km of the western Istrian coast. The sampling was performed seasonally at 1 and 3 m depth by destructive (determination of species cover and biomass) and non‐destructive (determination of species coverage using digital photography) methods. When assessed at 1 m depth the spatial scale weighted EEI for the west Istrian coast was 8.1, corresponding to an ecological status class (ESC) value of high. However, data for 3 m depth gave a spatial EEI of 6.72 which corresponds to an ESC value of good. Regressions of the ratio of ecological state group I (ESG I, i.e. thick leathery, calcareous and crustose species) over total algal abundance with the pollution gradient (obtained using principal components analysis (PCA) ordination of environmental variables) were significant at 3 m but not at 1 m depth. This was due to the high abundance of ESG I macroalgae Corallina elongata and Cystoseira compressa at 1 m depth at polluted stations. Similar regressions were obtained using cover, biomass and coverage. It is concluded that the EEI method may be suitable for the classification of coastal waters in the northern Adriatic only in certain cases. A better assessment of ecological status using this method would require more realistic estimations based on the inclusion of data from several sampling depths. As all three abundance measures (cover, biomass, coverage) gave similar results, coverage (using digital photography) is suggested as being a preferred measure owing to the rapidity of sampling at several depths and less time‐consuming laboratory work. Copyright © 2008 John Wiley &amp; Sons, Ltd.