environmental-dna-sampling-from-whale-watching-vessels-for-cetacean

Environmental DNA Sampling from Whale-Watching Vessels for Cetacean Monitoring

Environmental DNA (eDNA) offers a non-invasive approach for monitoring cetaceans, yet its widespread application from operational platforms requires ...

Politecnico di Milano DICA Civil and Environmental Engineering Department

Diffuse pollution is generally indirectly estimated by area and specific emission factors as function of land use. However in many cases these estimates were proven to be remarkably inaccurate. Aim of this study was to combine a water quality simulation model, (USEPA-QUAL2E) and Factor Analysis to increase the understanding of the water pollutants source apportionment. The study concerned two different watersheds, an upland area characterised by a very scarce agricultural use, and another area covering both the upland and the lowland physiographic regions. Particularly the lowland region is included in one of the most productive agricultural areas in Italy. By comparing instream measurements with QUAL2E simulations during dry and wet weather conditions, a good fit (errors +/-20%) was found for the dry weather scenario, whereas very poor was the model performance on the wet weather scenario. This was in the same way expected since the rainfall-driven pollutants scenario deviates significantly from QUAL2E general assumptions of constant emissions in steady state streamflow conditions. However the poor fit was also due to the scarcer reliability of the adopted non point emission estimates. Despite of approximations the model wet weather simulations enabled to estimate the non point contribution to the instream load at the rainfall event scale resolution. Such diffuse sources contribution was found around 80% in the area of extensive agricultural land use, and around 40% in the upland region. Factor Analysis applied to the instream measurements data shed light on the exchange from the groundwater to the surface water system that occurred in the upland region. The hypothesis of a groundwater contribution to the instream total load of nitrates was also supported by QUAL2E simulations that, when considering only the point loads, systematically underestimate the dry weather nitrate concentrations. The same pattern was not observed for the lowland region.

Combined use of the EPA-QUAL2E simulation model and factor analysis to assess the source apportionment of point and non point loads of nutrients to surface waters.

Recent observations of cetacean mass strandings, coincident with anthropogenic sounds emissions, have raised concerns on the potential environmental impact of underwater noise. Cuvier's beaked whale (Ziphius cavirostris) was reported in all the cited stranding events. Within the NATO Marine Mammal Risk Mitigation project (MMRM), multiple interdisciplinary sea trials have been conducted in the Mediterranean Sea with the objective of developing tools and procedures to mitigate the impact of underwater sound emissions. During these cruises, visual observations, passive acoustic detections and environmental data were collected. The aim of this study was to evaluate "a priori" predictions of Cuvier's beaked whale presence in the Alboran Sea, using models developed in the Ligurian Sea that employ bathymetric and chlorophyll features as predictors. The accuracy of these predictions was found adequate and elements are given to account for the uncertainties associated to the use of models developed in areas different from their calibration site.

Risk mapping for sensitive species to underwater anthropogenic sound emissions: model development and validation in two Mediterranean areas.

The Lambro-Seveso-Olona (L-S-O) system derives from the human regulation of the natural hydrology of the territory around Milan city area. The average population density in the L-S-O area is among the highest in Italy and Europe. Industry is also highly developed in this basin: chemical, textile, paper, pulp and food industries being the most important ones. Although, at present, the L-S-O system no longer receives the untreated wastewaters of the Milan urban area, treated wastewaters constitute about half of the streamflow. Biotic communities in this river have a long history of poor quality status, having suffered great damage due to domestic and industrial discharges. Recently, new chemical quality standards for macropollutants have been set by the Italian legislation as support for the good ecological status according to the Water Framework Directive (WFD). This new index is very restrictive, and it makes it extremely challenging to achieve the water quality objectives for the L-S-O system. The aim of this study is to analyse through a modelling exercise the restoration possibilities of the L-S-O system, investigating both the source apportionment of the macropollutants, the discharge limits that should be set to achieve the good quality status and their corresponding cost.

Searching for a compromise between ecological quality targets, and social and ecosystem costs for heavily modified water bodies (HMWBs): the Lambro-Seveso-Olona system case study.

The Marine Strategy Framework Directive (MSFD) requires the assessment of the environmental status in relation to human pressures. In this study the biodiversity of the cetacean community is proposed as MSFD descriptor of the environmental status and its link with anthropogenic pressures is investigated. Functional groups are generally favoured over indicator species since they are thought to better reflect to anthropogenic stressors. Cetaceans are in many situations the most well known component of pelagic ecosystems. Their habitat requirements are known and can be used to evaluate the theoretical biodiversity that should be expected in a certain area. The deviations between the theoretical biodiversity and the actual biodiversity may be used to detect the impacts of human activities. Based on this analysis fishery resulted to be by far the most significant of the existing pressures. Among all the species, bottlenose dolphin was found the most correlated with the fishery sector dynamics.

An index based on the biodiversity of cetacean species to assess the environmental status of marine ecosystems.

Stream ecosystems may suffer from the effects of multiple stressors. Planning restoration actions without knowing the relative weight of each stressor might lead to disproportionately costly or ecologically meaningless measures. This is particularly relevant under the EU Water Framework Directive where economic considerations play a role in justifying exemptions from the overarching aim of the directive of achieving the good ecological status in all the EU water bodies by 2015. In this study, we correlated the status of macroinvertebrate assemblages with many environmental variables at 120 monitoring stations (surveyed in 2009-2011) in the streams of Lombardy, Italy. We used a combination of regression techniques to disentangle the effects of the different stressors. Furthermore, different profiles of ecological quality were associated with the dominant stressors. Finally, examples are given about how these study findings provide elements to identify restoration scenarios that maximize the effectiveness/cost ratio.

Disentangling the multiple stressors acting on stream ecosystems to support restoration priorities.

This paper provides a summary of 25 years of research on Risso's dolphins (Grampus griseus) in the western Ligurian Sea. Seasonal variations in abundance, distribution and habitat use were observed. Photographic mark-recapture methods provided a population size estimate for the period from 1998 to 2012, of about 100 individuals (95% CI of 60-220 individuals). The same methods detected a decline in population size from an average of about 120-150 from 2000 to 2005, to an average of 70-100 during 2010 to 2014. Species occurrence appeared to be significantly decreasing in coastal and continental slope areas, while it seemed to be stable in the most pelagic area. In addition, a dramatic change was observed in the local primary production, which was analysed based on time series of sea surface temperature and chlorophyll data from 1990 to 2014. Based on fisheries landings, there may have been a general decrease in fishery productivity, both in the western Ligurian Sea and in adjacent regions. Environmental variability, depletion of resources by fisheries and possibly interspecies competition may all have contributed to cause changes in Risso's dolphin habitat use and occurrence in the western Ligurian Sea.

Risso's Dolphin, Grampus griseus, in the Western Ligurian Sea: Trends in Population Size and Habitat Use.

Groundwater status in highly urbanized areas is particularly affected by anthropogenic influence due to diffuse pollution deriving from many sources. This makes very often challenging to determine whether the observed groundwater conditions are the result of localized pollutant sources (PS-Point Sources). In the EU legislative framework it is accepted that, when Natural Background Levels (NBLs) of undesirable elements are proven to be higher than specific Groundwater Quality Standards (GQSs), NBLs should be assumed as GQSs. No procedure is instead defined when anthropogenic Diffuse Pollution Background levels (DBPLs) are higher than GQSs and make unfeasible any remediation strategy. Among the many contaminants affecting groundwater, the chlorinated solvents, tetrachloroethylene (PCE), trichloroethylene (TCE) and trichloromethane (TCM) among the organics and hexavalent chromium, among the inorganics, having been widely used in several industries all over Europe, are very often the most prevalent contaminants in soil and groundwater. Aim of this paper is to discuss a multivariate statistical approach to address the issue of identification of anthropogenic Diffuse Pollution Background Levels. With such aim, an area of about 1600 km, including the Functional Urban Area of Milan, was considered and 10 independent geochemical datasets, provided by local and regional agencies, and covering the period 2003-2014 were merged into a single database after homogenization and multiple quality checks. A total of 618,258 chemical analyses from 3477 sampling wells were considered, being all samples collected and analyzed through internally consistent protocols. The analysis enabled to identify five main clusters, having specific hydrogeological characteristics, different temporal profiles and pollutant background concentration levels, which were also found to respond differently to meteo-climatic changes. This study offers a robust knowledge basis for drafting a diffuse pollution management plan of the area.

Groundwater diffuse pollution in functional urban areas: The need to define anthropogenic diffuse pollution background levels.

In recent years, per- and polyfluoroalkyl substances (PFAS) have emerged as major pollutants of concern. This study considered a real case of superficial and groundwater contamination caused by a set of 15 persistent, carcinogenic, and bioaccumulative compounds. The study area is the Veneto Region floodplain in Italy, where a huge contamination mainly caused by a persistent spill-over from a former chemical factory was discovered in 2013. The contamination path studied in 2013 followed mainly two directions: the first towards east, to the city of Vicenza, and the second following the course of Chiampo and Agno streams, southwards. To identify the major patterns of contamination, a Factor Analysis (PCA) in conjunction with a Cluster Analysis (CA) was performed. The reviewed dataset is composed by PFAS concentration values collected from 2013 to 2021 in groundwater, superficial waters, in natural sources, and in proximity to three industrial discharges, throughout a 3600 km area. The CA results were cross-referenced with the water table interpolation, yielding a match between the groundwater flow directions and the observed patterns of the two main plumes. The persistence of pollutants was finally investigated by analyzing distances between the former chemical factory, an industrial wastewater collector which lies along Chiampo and Agno valleys that host residential and industrial areas, and the other sampling points collected in the dataset. The findings confirmed the importance of assessing anthropic background levels of contamination and highlighted the necessity to include the PFAS issue in a national health-based drinking water quality guideline.

Cluster and multivariate analysis to study the diffuse contamination of emerging per- and polyfluoroalkyl substances (PFAS) in the Veneto Region plain (North-eastern Italy).

Ocean liming (OL) is a potential carbon dioxide removal (CDR) method that aims to increase the ocean's capacity to absorb atmospheric CO by adding hydrated lime to the surface ocean. Modeling studies indicate that OL may cause temporary pH spikes lasting several minutes, depending on the lime sparging rate. Little is known about the short-term effects of these spikes on marine organisms. Aim of the present study is to investigate these effects on the copepod Acartia tonsa. Copepods were exposed to different pH conditions (9, 10, 11, 12) by dosing different hydrated lime solutions. Copepod mortality, movements, and behavior were recorded. At pH 9 for short exposure times (<6 h), no negative effects were observed indicating a potential tolerable threshold for OL applications. At longer exposure times (>6 h) and pH higher than 9, negative effects (mortality and sublethal effects) were found significantly higher than in the control.

Short-term impact assessment of ocean liming: A copepod exposure test.

Mitigating global warming requires urgent reductions in carbon dioxide (CO₂) emissions and the development of Carbon Dioxide Removal (CDR) strategies. pH-equilibrated Ocean Alkalinization (pHOA) has emerged as a promising method to enhance CO₂ sequestration while minimizing potential environmental risks. This study investigates the ecological impact of pHOA on phytoplankton communities through a mesocosm experiment in the Gulf of La Spezia (Italy) using local seawater treated with Limenet® technology. We assessed planktonic responses to different levels of bicarbonate-enriched seawater (Control, Low, Medium, High, Oversaturated) by monitoring changes in carbonate chemistry, nutrient availability, and phytoplankton community composition over 15 days. Results revealed that pHOA treatments (excluding the oversaturated condition) helped maintain greater ecological stability, reducing the rate of diatom/dinoflagellate community shifts and supporting higher silicon uptake, particularly by diatoms. In contrast, oversaturation led to carbonate precipitation and a significant loss of added alkalinity. The findings suggest that moderate pHOA may enhance phytoplankton resilience and promote diatom activity under altered carbonate chemistry. This study underscores the need for further research to evaluate the broader ecological implications of pHOA.

Article	Year
Combined use of the EPA-QUAL2E simulation model and factor analysis to assess the source apportionment of point and non point loads of nutrients to surface waters. The Science of the total environment\| PubMed ID: 16677687	2006
Risk mapping for sensitive species to underwater anthropogenic sound emissions: model development and validation in two Mediterranean areas. Marine pollution bulletin\| PubMed ID: 21349554	2011
Searching for a compromise between ecological quality targets, and social and ecosystem costs for heavily modified water bodies (HMWBs): the Lambro-Seveso-Olona system case study. Water science and technology : a journal of the International Association on Water Pollution Research\| PubMed ID: 23925198	2013
An index based on the biodiversity of cetacean species to assess the environmental status of marine ecosystems. Marine environmental research\| PubMed ID: 25016937	2014
Disentangling the multiple stressors acting on stream ecosystems to support restoration priorities. Water science and technology : a journal of the International Association on Water Pollution Research\| PubMed ID: 26177413	2015
Risso's Dolphin, Grampus griseus, in the Western Ligurian Sea: Trends in Population Size and Habitat Use. Advances in marine biology\| PubMed ID: 27770985	2016
Groundwater diffuse pollution in functional urban areas: The need to define anthropogenic diffuse pollution background levels. The Science of the total environment\| PubMed ID: 30625652	2019
Cluster and multivariate analysis to study the diffuse contamination of emerging per- and polyfluoroalkyl substances (PFAS) in the Veneto Region plain (North-eastern Italy). Chemosphere\| PubMed ID: 36706810	2023
Short-term impact assessment of ocean liming: A copepod exposure test. Marine pollution bulletin\| PubMed ID: 38043201	2024
The response of phytoplankton to pH-equilibrated ocean alkalinization: A mesocosm experiment with harbour waters. Marine pollution bulletin\| PubMed ID: 41066847	2026

Arianna Azzellino

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