Common patterns of functional and biotic indices in response to multiple stressors in marine harbours ecosystems

Evaluating the effectiveness of M-AMBI with other biotic indexes in a temperate estuary

Need for a scalable and widely applicable index has been increasingly important. This study evaluates the applicability of the M-AMBI, a potential comprehensive index, at small spatial scales. M-AMBI was compared to regional indices (EMAP-E and GOM B-IBI), assessing response to natural environmental gradients and low oxygen stress. Results indicate poor agreement between indices with M-AMBI and GOM B-IBI showing positive correlation but significant disagreement in habitat condition. EMAP-E had no agreement. Indices showed similar patterns of better habitat scores in higher salinities. M-AMBI also showed a negative relationship with sediment organic matter and total nitrogen. DO influenced all indices with M-AMBI the most sensitive. However, mismatches between DO and index score were observed further calibration may be needed before adoption into programs. Overall, the M-AMBI demonstrates potential at smaller, local scales, but additional studies are needed to validate its performance in different coastal environments and under different conditions.

Difference between invasive alien and native vegetation in trapping beach litter: A focus on a typical sandy beach of W-Mediterranean Basin

Beach litter is one of the most pervasive pollution issues in coastal environments worldwide. In this study, we aim to assess the amount and distribution of beach litter on Porto Paglia beach, its entrapment across psammophilous habitats, and whether the invasive Carpobrotus acinaciformis (L.) L.Bolus plays a different role in trapping litter than native vegetation. To this end, two seasonal samplings (in spring and autumn) were conducted using a paired sampling method that considers plots in all coastal habitats with and without C. acinaciformis. Our results confirm that the main beach litter category is plastic, and that its distribution varies across habitats: the white dune seems to play a greater role in trapping and filtering beach litter, reducing its amount in the backdune. A correlation was found between the Naturalness index (N) and the beach litter amount, supporting the finding that invaded habitats trap beach litter better than native ones.

Taxonomic and functional structure of macrobenthic invertebrate communities and their response to environmental variables along the subbranches of the Nile River (rayahs), Egypt

Macrobenthic invertebrate communities serve as markers of anthropogenic stress in freshwater ecosystems. In this study, 17 sampling sites were selected from two Nile river subbranches (El-Rayah El-Behery and El-Rayah El-Nassery) and subjected to different anthropogenic influences to explore the ecological environment and characteristics of macrobenthos communities. Macrobenthos were studied using taxonomic diversity and biological trait analysis to investigate how human activity and variation in water quality affect their structure and function. A total of 37 taxa represented by 43,389 individuals were recognized. The communities are composed chiefly of Oligochaeta and aquatic insects. Multivariate statistical analyses found that the most influential environmental variables in the structural and functional community were sodium, dissolved oxygen, silicate, pH, calcium, and cadmium. At high levels of pollution, notably sewage and industrial pollution in the northern part of El-Rayah El-Behery, characteristics such as larger body size, detritus feeders, burrowers, and high tolerance to pollution predominated, whereas at low levels of pollution, features such as small body sizes, scraper and predator feeders, intolerant and fairly tolerant of pollution, and climber and swimmer mobility are predominant. The results confirm our prediction that the distribution of macroinvertebrate traits varies spatially in response to environmental changes. The diversity-based method distinguished impacted sewage and industrial sites from thermal effluent sites, while the trait-based approach illustrated an apparent variance between the ecological status of contaminated regions. Therefore, the biological features should be employed in addition to structural aspects for assessing the biodiversity of macroinvertebrate communities under environmental stressors.

Functional diversity of macrofaunal assemblages as indicators to assess heavy metal pollution in the Bohai Sea, China

Functional diversity of macrofaunal assemblages can reflect the composition and differences of functional traits, indicating their response to various contaminants, especially heavy metal pollution. We explored the effects of environment variables over gradients of heavy metal pollution on macrofaunal assemblages, using biological traits analysis, generalized linear model (GLM), AZTI marine biotic index (AMBI), and various biodiversity indexes. The RLQ (co-inertia analysis) and fourth-corner approaches were used to investigate the specific response of functional traits to heavy metal pollution. Most sites were environmentally degraded by heavy metal pollution and macrofaunal body size had a miniaturization trend. There was a significant correlation between functional diversity indexes and AMBI. The RLQ and fourth-corner analysis and GLM models showed that heavy metal and natural environmental gradients had a profound effect on functional diversity. The functional divergence and dispersion indexes, along with the abundance of some specific species, were appropriate indexes for heavy metal pollution.

Short-term colonization of fouling communities within the port of Livorno (Northern Tyrrhenian Sea, Western Mediterranean): Influence of substrate three-dimensional complexity on non-indigenous species establishment

The influence of substrate morphology on early stages of fouling development was assessed through submerged experimental substrates with different morphological complexity. The experiment was carried out within commercial and touristic harbours of the port of Livorno (Italy), analysing the communities at three steps of colonization (14, 28, 42 days). We assessed the effect of substrate complexity on recruitment of non-indigenous species (NIS), combined with the influence of port use destinations. NIS were recorded in both use destination areas since the first step of colonization. Substrate morphological complexity significantly affected fouling colonization and particularly NIS assemblages. We found that high-complexity substrates are particularly suitable for NIS establishment in comparison with less complex ones. The touristic harbour exhibited a potential for fouling colonization higher than the commercial harbour. These results contributed to the understanding of factors involved in NIS establishment and spread, as well as in their spatial-temporal dynamics within port environments.

Intertidal macroinvertebrate community structure in a subtropical channel is driven by sediment properties across different land-use types

Macroinvertebrate community in the intertidal setup plays an important role in coastal ecosystem functions and biogeochemical cycle. However, different land use pattern may influence on their community structure, diversity, and composition in the coastal ecosystems. Using Van-Veen grab sampler, 60 sediment samples were seasonally collected from mangroves-dominated, aquaculture-dominated, and anthropogenically affected area in the lower intertidal zone of the Kohelia channel of Bangladesh, the Northern Bay of Bengal. We have tasted the variation in sediment properties across three land-use types in this intertidal habitat. To understand the patterns of benthic macroinvertebrate distribution, a neutral community model was applied. Our results showed that community composition and biodiversity of the benthic macroinvertebrate communities varied significantly between mangrove-dominated area with anthropogenically affected areas among the four seasons. The neutral community model revealed that community assembly of benthic macroinvertebrates in the lower intertidal habitats is structured by stochastic processes while sediment properties have significant influence on species distribution and interactions. Results suggested that land-use changes altered sediment properties and could change the diversity and distribution of the macroinvertebrate communities in the lower intertidal habitats.

Assessment of heavy metals in surface water, sediment and macrozoobenthos in inland rivers: a case study of the Heihe River, Northwest China

Long-term retention and accumulation of heavy metals in surface water and sediment pose a great threat to the sustainable development of aquatic ecosystems and human health. In this research, macrozoobenthos, and surface water and sediment heavy metal (Mn, Cr, Cu, Ni, Pb, Zn, Cd, and As) samples were collected from 23 sites in the upper and middle reaches of the Heihe River in the summers of 2019-2020. The interrelationships between heavy metals and macrozoobenthos were analyzed by Pearson correlation analysis and redundancy analysis (RDA), and the contamination level and potential ecological risk of the heavy metals in surface water and sediments were assessed by comprehensive pollution index (WQI), single potential ecological risk index ([Formula: see text]), and sediment quality guideline-quotient (SQG-Q), respectively. The results showed that the level of heavy metal pollution in the surface water of the Heihe River was extremely low, but the contents of Mn and Pb exceeded the third class of surface water environmental quality standards (GB 3838-2002). The spatial distribution of heavy metals in surface sediments were significantly different, and the average concentration of 8 heavy metals exceeded the background values of Gansu Province. Meanwhile, the pollution level of heavy metals in surface sediments was high pollution, and the ecological risk level was moderate risk. Combining [Formula: see text] and SQG-Q evaluations showed that Cd, Ni, and Cr were the main ecological risk factors. In addition, the distribution coefficients of Cr and Cd were low, indicating that Cr and Cd were easily released from the surface sediments, causing secondary pollution. In terms of the source of the heavy metals, Cu, As, Zn, Cr, and Ni mainly came from industrial and agricultural wastewaters, Pb was from the mining industry and natural sources, and Mn and Cd mainly came from tailings and their landfill leachate. Basommatophora and Araneae can be used as potential indicator organisms for heavy metal pollution in surface water, and Basommatophora, Coleoptera, Hemiptera, and Araneae can be used as indicator species for heavy metal pollution in surface sediments. The study showed that macroinvertebrate community characteristics had a sensitive response to heavy metals in the surface waters and sediments of the Heihe River, which can be used to evaluate the pollution status of heavy metals in inland rivers.

Assessing the sewage discharge effects on soft-bottom macrofauna through traits-based approach

We assessed the effect of sewage-derived materials on the structural and functional attributes of the soft-bottom macrofauna at an increasing distance from the entire diffusion area. Our results showed clear spatial changes of macrofaunal density and biomass along the distance gradient from the main outfall. High values of biodiversity, species composition, and species linked to organic enrichment near the duct suggested that moderate organic stress affected this community. The traits analysis abundance-based, compared to biomass-based one, distinguished most clearly sewage contamination conditions. Functional diversity displayed spatial patterns with higher values in the less impacted sites and was significantly related to species numbers and the biotic indices (like M-AMBI). This approach is ideal for detecting macrofaunal functional changes due to sewage contamination. Thus, we infer that traits analyses could offer great potential for environmental assessment and monitoring of coastal areas influenced by human activities.

Ecological status assessment and non-indigenous species in industrial and fishing harbours of the Gulf of Gabès (central Mediterranean Sea)

Port Biological Baseline Surveys (PBBS) are standardized surveys of the indigenous and non-indigenous marine biodiversity within harbour activities. They provide a baseline for monitoring changes in the structure and function of harbour communities. This study conducted in 12 fishing and industrial harbours from January to December 2018 was the first initiative of a Port Baseline Survey aimed to assess the impact of biological invasions in harbours of the Gulf of Gabès (GG), Tunisia. A total of 174 macrobenthos species were recorded, belonging to eight phyla, with a dominance of crustaceans (32%), molluscs (31%) and polychaetes (20%). Among these species, 57 were non-indigenous species (NIS) for Tunisian waters, while 27 species were recorded for the first time in GG harbours, and three decapods (Dyspanopeus sayi, Hippolyte prideauxiana and Pilumnus minutus) and one amphipod (Hamimaera hamigera) were newly recorded from Tunisian waters. Two main categories of harbours are distinguished according to their macrobenthic communities and environmental conditions. The industrial harbours yield higher richness and abundance of NIS than the fishing harbours. The ALEX metric is used to evaluate the biological invasion status of the Gulf of Gabès harbours and shows that their status ranges from unaffected in fishing harbours to extremely affected in industrial harbours. Three biotic indices (AMBI, BO2A and BENTIX) are applied to assess the ecological status of harbours, which varies from moderate to good. ALEX and the other biotic indices are significantly correlated with harbour characteristics, maritime traffic and edaphic factors (organic matter and chemical contamination). The present study provides a data baseline for the implementation of environmental policies and management plans in the future.

Comparison of different ecotoxicological batteries with WOE approach for the environmental quality evaluation of harbour sediments

This study was conducted under the Italian Ministerial Decree D.M. 173/2016 which regulates the assessment of the Sediment Class Quality in Italy using ecotoxicological bioassay and chemical analysis (Weight-Of-Evidence model). The aim of this work was to evaluate the real classification obtained by the theoretically equivalent responses of nine different combinations of batteries based on six different species: Aliivibrio fischeri (inhibition of bioluminescence), Phaeodactylum tricornutum, Skeletonema costatum, Dunaliella tertiolecta (inhibition of algal growth), Paracentrotus lividus and Crassostrea gigas (embryotoxicity). Bioassays, in many cases, showed a non-bioavailability effect of the pollutants; these one highly revealed by the chemical analyses. Algal species showed responses very similar from each other. Otherwise, species used for embryotoxicity produced wide responses, consequently modifying the quality class of sediments and the handling management (i.e. landfill confinement or beach nourishment) allowed by the Law.

Response of macrobenthic communities to heavy metal pollution in Laoshan Bay, China: A trait-based method

The effects of multiple natural and anthropogenic stressors on the functional trait composition and diversity of marine macrobenthic communities in Laoshan Bay were investigated using biological trait analysis (BTA). Seven traits, including 27 trait modalities and four functional diversity indices (functional richness, functional evenness, functional divergence, and Rao's quadratic entropy), were considered. The results of RLQ (environmental variables (R), species taxa (L), and traits (Q)) and variance partitioning analysis (VPA) showed that the trait compositions and functional diversity of macrobenthic communities were influenced by a combination of stressors, among which heavy metals were the major factors. At the sites with high heavy metal pollution, the prevalent traits were infauna, burrower, and deposit feeder, whereas epifauna, carnivores and crawlers were dominant at the sites of low heavy metal contamination. The impact of natural environmental gradients on macrobenthic communities is also worthy of attention.

Ecological quality assessement of marinas: An integrative approach combining biological and environmental data

The importance of marinas as infrastructures for recreational boating is increasing substantially. However, information on their soft-bottom benthic communities, a key tool for managing programmes, is still scarce. We combined environment features with macro- and meiofaunal soft-bottom community information for assessing the ecological status of marinas with an integrative approach. To address this issue, we focused on eight marinas of the Southern Iberian Peninsula. Macro- and meiofauna data revealed high benthic heterogeneity at a spatial scale. The environmental variables which correlated best with macrofauna were mainly phosphorus, granulometry, and total organic carbon, and secondarily important variables were faecal coliforms, the biocide Irgarol, and heavy metals; total hydrocarbon concentration was also significant for meiofauna. Annelida was the dominant phylum in terms of number of species (37%) and abundance (66%) and were better descriptors of the environmental conditions than Arthropoda and Mollusca. Although identification to the species level is desirable and mandatory for assessing biological pollution, significant differences among marinas and correlations between fauna and abiotic variables were already detected at the level of family and order. This implies that biota assessment at higher levels may still be useful in monitoring programmes limited by time and budget constraints. The major novelty of this study lies in the development of an integrative assessment method based on the following selected ecological indicators: Marinas Environmental Pollution Index (MEPI), Biocontamination Index (BCI), macrofaunal biotic indices (AMBI, M-AMBI, BENTIX, MEDOCC and BENFES), macrofaunal taxa richness and Shannon-Wiener's diversity, and nematode:copepod index. This approach was able to discriminate marinas of the Southern Iberian Peninsula based on their ecological status, which ranged from poor to good. The method can be useful to design standards for assigning "sustainable quality seals" to those marinas with better values of ecological indicators.

Seafloor litter along the Italian coastal zone: An integrated approach to identify sources of marine litter

A heterogeneous amount of waste of different origins is continuously generated along Italian coasts in the Mediterranean Sea. In this paper, using information regarding the quantities and the different types of marine litter based on Project AWARE's "Dive Against Debris" data, we try to identify the main sources of this waste. In particular, the methodological approach used associates the origin of marine litter sources with the dataset of geo-localised state-owned maritime concessions, which are loaded by the granting bodies (regions, municipalities, port authorities) on the State Property Information System (Sid). The sources of marine litter were evaluated using the matrix scoring technique (MST). Then, to assess the weight of each source in each station, the community-level weighted mean (CWM) was calculated. Single-use plastic accounted for the highest percentage (19.13%), followed by glass beverage bottles (10.90%), shopping bags (9.03%), aluminium beverage cans (4.91%), and cigarette butts (4.61%). Tourism and beach users contributed to 42.3% of the litter found, followed by fishing (15.7%) and yachting (11.3%). The overlapping of the data collected by scuba divers with the state concessions of activities from offshore and mainland areas was used to distinguish the anthropic pressures that impact the coast. Policy makers and the local administrator may use these results to define new methods of collection and reuse of anthropic waste through a more harmonised approach in the management of marine waste.

Functional changes in benthic macrofaunal communities along a natural gradient of hypoxia in an upwelling system

Increasing global concern has been raised about the expansion of hypoxia in coastal waters and its potential to impact benthic ecosystems. Upwelling areas offer opportunities to study the effects of hypoxia on benthic communities under natural conditions. We used a biological trait-based approach and estimated functional diversity indices to assess macrobenthic community functioning along a depth gradient associated with naturally increasing hypoxia and concentrations of organic matter in the upwelling zone of northern Chile (South-East Pacific) over two years. Our results highlighted the increasing dominance of opportunistic biological traits associated with hypoxia and high organic matter content. Habitat filtering was the main process affecting the studied communities. Functional diversity patterns were persistent overtime despite the occurrence of a pulse of oxygenation. This study contributes to our understanding of how natural hypoxia impacts macrobenthic communities, providing useful information in the context of increasing eutrophication due to human influence on coastal areas.

The impact of marine litter from fish aggregation devices on vulnerable marine benthic habitats of the central Mediterranean Sea

The aim of this research was to assess marine litter abundance and its effects on the benthic fauna in an area of the central Mediterranean Sea exploited by fisheries using fish aggregating devices (FAD). The study was carried out by means of a remotely-operated vehicle (ROV). Derelict fishing gear, mainly FAD ropes, represented the main source of marine debris, contributing 96.2% to the overall litter. About 47% of debris items (mostly FAD ropes) entangled colonies of the protected black coral Leiopathes glaberrima. The results of this research will assist in the monitoring of "impact/harm" to the coral and other benthic communities, as recommended by the Marine Strategy Framework Directive and by the Integrated Monitoring and Assessment Programme. Preventive and mitigation measures (i.e., biodegradable fishing gear, onboard technology to locate and retrieve gear, reception and/or payment for old/retrieved gear, and introduction of no-take zones) to reduce the problem are discussed.