Assessing fish quality status in transitional waters,within the European Water Framework Directive: Setting boundary classes and responding to anthropogenic pressures

Validation of the AZTI's Fish Index (AFI), proposed for the Basque Country (northern Spain), in assessing fish quality within the Water Framework Directive (WFD), is undertaken. The response to anthropogenic pressure is investigated, in setting the boundaries between the different quality status classes. Hence, 12 estuaries were sampled, at different frequencies, between 1989 and 2007, by means of a beam trawl. Significant (p < 0.0001) correlations were found between the AFI and oxygen saturation and ammonia. Oxygen quality standards are used to set boundaries between quality classes. Then, the AFIs obtained are compared with different anthropogenic pressures, including urban and industrial discharges, engineering works and dredging. The effects of the removal of some of these pressures are also studied. The total number of pressures within an estuary shows significant (p < 0.009) negative correlation with AFI, explaining between 51 and 62% of the variability in fish quality. The impact of pressures upon fish and demersal assemblages is detected as required by the WFD. Nonetheless, further investigation and intercalibration of the methods used, are necessary.     

基于AMBI和M-AMBI法的底栖生态环境质量评价——以厦门五缘湾海域为例

于2011-2013年5月和10月在厦门五缘湾海域设置7个站位进行大型底栖动物调查,并结合2005年的历史数据,运用AMBI和M-AMBI指数法评价该海域海底生态环境质量的时空变化状况。2011-2013年共鉴定大型底栖动物9门106科193种,多毛类(83种)、甲壳类(53种)和软体动物(25种)是该海域的主要优势类群,平均总密度和湿质量生物量分别为(518±292)ind/m2和(54.8±88.9)g/m2。多毛类的短鳃树蛰虫(Pista brevibranchia)为该海域的绝对优势种,其平均密度可达(170±179)ind/m2,其他优势种还有似蛰虫(Amaeana trilobata)、西方似蛰虫(Amaeana occidentalis)、丝鳃稚齿虫(Prionospio malmgreni)、梳鳃虫(Terebellides stroemii)、独毛虫属一种(Tharyxsp.)、菲律宾蛤仔(Ruditapes philippinarum)、长指马尔他钩虾(Melita longidactyla)和伍氏蝼蛄虾(Austinogebia wuhsienweni)等。评价结果显示,该海域底栖生态系统受轻度干扰,生态环境质量介于一般—优良之间,与2005年的调查相比,2011-2013年该海域的生态环境质量有所好转,这可能与五缘湾及周边海域近年来进行的海堤开口改造、海洋环境整治,以及海湾纳潮量及水交换能力的改善有关。     

Assessing the ecological status of the North-western Adriatic Sea within the European Water Framework Directive: a comparison of Bentix, AMBI and M-AMBI methods

In this paper we looked for the most suitable method for benthic ecological quality status (EcoQS) assessment of the North-western Adriatic Sea. Taking into account the historical and present information, we inter-compared our expectations in terms of EcoQS, with the Bentix, AMBI and M-AMBI classification metrics results, and investigated the sensitivity of these indices to the spatial, seasonal and inter-annual variability of benthic communities. The sampling sites were located at increasing distances with respect to the Po River mouth, along an (inverse) gradient of eutrophication. Moreover, a 2-year monthly monitoring plan (October 2004–September 2006) was carried out at the CEBEB site, located in a central position with respect to the investigated area. The results highlighted that the three indices differed in the sensitivity to spatial and temporal variability of the benthic communities. The strong seasonal and inter-annual changes in the benthic communities had a significant effect on the Bentix, whereas no relevant modifications were observed on the EcoQS assignation obtained using the M-AMBI and AMBI methods. The environmental quality ratios (EQR) values and EcoQS classification obtained by the Bentix and AMBI did not match expectations, as they were not inversely correlated with the site distances with respect to the Po mouth, whereas the M-AMBI clearly discriminated the most and the least eutrophicated sites. It thus appears that the M-AMBI could be considered to be the most valuable method for the ecological-status assessment of the North-western Adriatic Sea benthic ecosystem.     

Influence of sample size on ecological status assessment using marine benthic invertebrate‐based indices

Routine monitoring of the quality status of water bodies demands the best cost‐benefit relation and sample‐size reduction is therefore welcomed. However, great caution is needed because such reduction affects the accuracy and variation of the results. In the present study we tested the influence of sample size (number of replicate samples) on reference condition values and within‐sample ecological quality ratio (EQR) variability of six commonly used ecological indices (taxa richness, Shannon–Wiener diversity, AMBI, Medocc index, Bentix and M‐AMBI). Analysis of soft‐bottom benthic invertebrate data from Slovenian coastal waters showed that sample size influenced the reference condition values of richness/diversity indices (taxa richness and Shannon–Wiener diversity) but not of the sensitivity/tolerance indices (AMBI, Medocc index, Bentix). Increased sample size decreased the within‐sample EQR variability and, concomitantly, increased the accuracy of site ecological status classification for all indices. The size of EQR variability differed depending on the index used. EQR variability of M‐AMBI, an index composed of metrics with different within‐sample EQR variability, was statistically the same as that of the metric with the lowest within‐sample EQR variability. Whether this is a common principle for multimetric indices remains to be confirmed. Based on these results, the use of at least three replicates is suggested to obtain reliable measures of reference condition and EQR for the assessment of ecological status. This level of replication is particularly necessary in areas with high diversity and environmental patchiness, and when richness/diversity measures and indices that include these measures are used.     

Implementation of the European Water Framework Directive: Natural variability associated with the CARLIT method on the rocky shores of the Ligurian Sea (Italy)

The Water Framework Directive (WFD) 2000/60/EC, adopted by the European Community in 2000 with the goal of maintaining and improving the aquatic environments, requires that member states achieve and maintain a good ecological status of all water bodies by 2015. In the marine context, the ecological status has to be quantified applying indexes based on appropriate key biological elements, which allow the categorization of water bodies into five Ecological Status (ES) classes. The CARLIT index is a cartographic monitoring tool enabling the Ecological Quality Ratio (EQR) to be calculated using macroalgae in coastal hard bottoms as a key biological element; at present it is being applied in Spain, France and Italy. To detect actual changes of water quality and, consequently, rely on the application of indexes for the assessment of the ecological status in the marine environment, it is necessary to evaluate their sensitivity to natural variability at different temporal and spatial scales. In this study we present a first quantification of natural (spatial and temporal) variability of EQR‐CARLIT quality assessment in 2006 and 2007 along the Ligurian coast (North‐Western Mediterranean, Italy). The EQR‐CARLIT values recorded along the Ligurian coastline show that natural variability of EQR‐CARLIT is low and that it does not affect the attribution of a given stretch of coast to a particular ES class, in agreement with the major human pressures acting in the area (urbanization, river load, sea‐farming). A small‐scale variability was detected, strengthening the use of cartography of the whole rocky shore, whenever possible, or, alternatively, the assessment of the ecological status for long stretches of coast, to encompass the small‐scale variability due to local factors.     

A methodology for defining homogeneous water bodies in estuaries – Application to the transitional systems of the EU Water Framework Directive

A methodology is developed and tested for division of estuarine and coastal systems into water bodies for monitoring and management purposes. This division is often implicit in the choice of sampling stations and in pollution abatement measures applied to different locations – it is now an explicit requirement of European Union Directive 2000/60/EC (Water Framework Directive) and recommended by United States Agencies such as EPA and NOAA. The approach considers both natural characteristics and the human dimension, by means of a stepwise methodology, which considers, on the one hand, morphology and salinity distribution, and, on the other, appropriate indicators of pressure and state. In the present application, nitrogen and phosphorus loading was used as the pressure component and chlorophyll a and dissolved oxygen as indicators of state. The criteria for system division were defined based on (1) an adimensional shape factor and salinity classes for the natural component; and (2) a normalised pressure index and (ASSETS) eutrophication symptom classes for the human dimension. Water quality databases and GIS were used to develop spatial distributions for the various components, and the results were aggregated into a final water body division, using tidal excursion as a “common sense” test. The methodology was applied to three well-studied systems in Portugal, a tubular estuary (Mondego), a wide lagunal estuary (Sado) and a coastal barrier island system (Ria Formosa). Although a final definition of water bodies will usually be a policy decision, this type of approach for the division of coastal systems into management units scientifically informs the decision-making process.     

A critical analysis on the response of macroinvertebrate communities along disturbance gradients: description of MEDOCC (MEDiterranean OCCidental) index

Macroinvertebrate communities inhabiting shallow sandy bottoms from Catalonia and Balearic Islands coastal waters (Western Mediterranean) were used to develop the Mediterranean Occidental (MEDOCC) index, a new methodology to assess the ecological status (ES) according to Water Framework Directive (WFD) requirements. The dominance pattern of four ecological groups (EG; sensitive, indifferent, tolerant and opportunistic organisms) was studied along a disturbance gradient. Sensitive taxa were present in disturbed situations and tolerant species were related to opportunistic taxa. The thresholds between ES were scaled according to the shifts in the dominance pattern of the EGs. The distribution of the EGs along the gradient of disturbance may vary depending on the studied communities, thus influencing the boundaries defining the ES. With the development of the MEDOCC index it is shown that analysing the response of the communities to the increasing gradient of disturbance is critical to enable an accurate proposal for boundary setting to be made, and to improve the applicability of the indices. AMBI (AZTI Marine Biotic Index), Bentix (Biotic Index), and MEDOCC indices were applied to the dataset to compare the ES obtained.     

H'、AMBI和M-AMBI指数在黄河口及邻近海域底栖生境健康评价中的适宜性研究

From a dataset of macrobenthos obtained from 18 cruises from 2004 to 2013 in the Huanghe(Yellow River)Estuary and its adjacent areas,the composition and characteristics of macrobenthos were analyzed,and the applicability of the Shannon-Wiener Index(H′),AZTI's Marine Biotic Index(AMBI) and multivariate AMBI(MAMBI) for assessing benthic habitat quality was compared.The results showed a total of 203 macrobenthos in the study area.The macrobenthos were dominated by polychaetes,followed by mollusks and crustaceans.The macrobenthic ecological groups were dominated by EGI,EGII and EGIII,which respectively accounted for 31.5%,36.0% and 21.2% of the total.There were significant differences between the evaluation results of the three indices.The ecological quality status(EQS) levels given by the AMBI were greater than those given by the H′ and M-AMBI.The AMBI could not reflect the differences between 11 sites but the H′ and M-AMBI could do.Moreover,the three indices responded well to the variations in salinity(S) and dissolved oxygen(DO) in the waters.The H′ and MAMBI also responded sensitively to the differences in physical parameters,such as water depth and sediment texture.The correlation between M-AMBI and environmental pressure gradient data was the strongest.The MAMBI could effectively distinguish degraded conditions from undegraded but the H′ and AMBI could not.Therefore,the M-AMBI reflected benthic habitat health well in the study areas.However,the objectivity of evaluation results of M-AMBI needs further verification by physical,chemical and biological methods.The thresholds also need further discussion.