ROSs Sea ecosystem aNd emeRging cOntaminants: new chaLlenges and potential threats in a changing worLd

Despite being one of the coldest and inhospitable region on Earth, Antarctica hosts a wealth of biodiversity and its isolation and extreme climate have lent a certain amount of protection to the many species that live the continent and its surrounding waters. However, Antarctica is threaten from a variety of stressors including climate change, ocean acidification, human activities (i.e. tourism, fishing, research stations), contaminants subjected to long range atmospheric and/or oceanic transport, and, not negligible, loss of sea ice that may induce short and long term alterations on the marine ecosystems, global carbon cycle and energy flows of ecosystems.
Our interest will be related to emerging chemical contaminants (ECCs), such as old and new brominated flame retardants (e.g. polybrominated diphenyl ethers and their metabolites, hexabromecyclododecanes), current use pesticides (e.g. chlorpyrifos, dachtal), perfluorinated compounds (e.g. PFOA, PFOS, and others), personal care products which, for their persistence and semi-volatility, may be found, even enriched, in Antarctica, far away from their initial emission sources. Rare earth elements (REEs) will also studied, being an emerging issue in many region of the planet. The determination of their occurrence and levels in seawater, sea-ice and organisms (criopelagic comunity, fish, Catharacta maccormickii, Pygoscelis adèliae and Aptenodytes forsteri) will allow to evaluate their background levels (local source inputs), the contribute of the Long Range Atmospheric Transport, bioaccumulation factors and effects on nutrient cycle. Seabird non-destructive samples (blood, unhatched eggs, feathers, faeces) will be collected by researchers highly experienced in handling and bleeding seabirds, along the Ross Sea coast from the Northern (Cape Adare) to the Southern (Inexpressible Island) Ross Sea coast, in order to evaluate a possible latitudinal gradient of contaminant concentrations and profile. This will allow to assess chemical local or distant source and transport from northern regions. Moreover, the bioaccumulation processes and factors will be evaluated taking into account the trophic level of organisms assessed by the analysis of the C and N stable isotope analyses (SIA). SIA have been used to characterise marine taxa and food webs, as isotopic signatures in a consumer's tissues reflect those in its food sources and have been shown to differ between guilds of primary producers, i.e. plankton and benthic and sympagic algae.
Although, SIA has been often used in describing trophic links in Antarctic habitats, data are strongly limited to specific organisms and few
attempts have been made to translate information on resource use into measures of population niche width and the uniformity of energy flows in the food web.
To assess the impact of contaminants on the health status of seabirds, their concentrations in blood samples will be correlated to blood parameters including thyroid hormones and prolactin. This will allow to evaluate the physiological impacts of exposure to contaminants (energy expenditure and stress); moreover our data will be correlated to other biological and ecological data.
The determination of legacy persistent organic pollutants (POPs), including PCBs and organochlorine pesticides will be also of particular
concern. In fact, these hazardous compounds, even banned and/or restricted from international regulations (Stockholm Convention
www.chm.pops.int), may have been stored in the last decades in the deeper layer of glaciers or ice shelves and be released and remobilised from these reservoirs during accelerated glacier ablation, becoming available again for bioaccumulation in organisms. This will also allow a temporal trend evaluation.
The lipid analyses of organism tissues will provide important data for the normalization of the POP concentrations and comparisons.
It is not always easy to assess the trophic position of polar organisms due to the rarity or difficulty of species collection. Thus, the ratio between the stable isotopes of carbon and nitrogen will also be performed and used in the elaboration and comparison of results.
ROSS’n’ROLL will also focus its attention on sea and pack ice which plays a fundamental role in the Antarctic ecosystems, because provides a habitat for microorganisms and the life cycle of many organisms in the region is dependent on the ice seasonality. Thus, melting ice may affect not only the sea level, but also the release of organic carbon stored in the ice. The biogeochemical cycling of organic carbon (OC) has important implications for aquatic system ecology because the abundance and molecular characteristics of OC influence contaminant transport and bioavailability, and determine its suitability as a substrate for microbial metabolism. Dissolved organic matter (DOM) is an important component of the global carbon cycle and provides a carbon source for microbial activity. Much of this carbon pool is composed of predominantly recalcitrant organic matter derived from microorganisms metabolism. The decrease of sea ice, the presence of snow and the mechanism of ice formation/melting, may considerably affect the carbon cycle, the mobility of contaminants and the biodiversity loss. A major challenge is to understand the fate of the material released into the water column after sea ice melt, by investigating the behavior of organic matter, organic contaminants and associated microbiological activities in function of the season weather features. The continuous release of old and emerging chemical compounds into the environment make difficult to assess their diffusion and impact on aquatic ecosystems. The fate of contaminants in water and the functional and structural responses of the microbial community are closely interconnected and depend on environmental conditions influenced, in turn, by climate change (e.g. presence/absence of sea ice). The repercussions of these dynamics are poorly understood and require a multidisciplinary approach for integrated research. To complete the picture, data modelling will increase the predictive capability with respect to where and when species will become more vulnerable to collapse, serving as early-warning system.
The analyses of intrinsic biogeochemical markers, such as stable carbon and nitrogen isotopes (stable isotope analyse, SIA) in biological tissues are used to investigate multiple ecological variables for marine species. Their successful application relies on a mechanistic understanding of isotopic variations at the base of the food web because those variations influence isotope values in higher trophic level species. SI are essential in ecotoxicological studies to investigate the correlation between POP levels and trophic levels and to model bioaccumulation and biomagnification.
Many (and main) species of the Ross Sea seabird trophic web will be studied with the aim to build the first iso-POP-scape (joint isotopic and pollution maps) for the Ross Sea. The achievement of the aims of this project will be possible through a multidisciplinary approach and high level of expertise involved and will answer to the Strategic Plan 2017-2019 established by the Italian National Commission for Antarctica (www.csna.it), to the SCAR Six priorities for Antarctic science (Nature 2014, 512:23–25), and to a SCAR Action Group on Input Pathways of persistent organics pollutants to AntarCTica (ImPACT) of the SCAR. It will also offer useful comparisons with other polar areas (e.g. Greenland) and information on ecosystem processes in the light of climate change. This study will be carried out in sea surface water samples, sea ice, and in target organisms (e.g. criopelagic comunity, fish, South Polar skua, Adèlie and Emperor penguins) collected in the coastal area surrounding MZS, along the Ross Sea coast.

ROSS’n’ROLL aims to evaluate the fate of emerging contaminants and their biological/ecological impacts, starting from the basis of the trophic food web (criopelagic communities) under different environmental conditions influenced by climate changes (e.g. presence/absence of sea ice, available nutrients, global warming). The tasks of the project are achieved by the collaboration among four OUs and with national and international collaborations. The specific aims of the Project are:
Task 1 - Ross Sea trophic web: generate a mechanistic-isotope based understanding to map the ‘iso-POP-scape’ of the Ross Sea studied
ecosystem; this is achieved by the evaluation of occurrence, levels, distribution and bioaccumulation factors of emerging contaminants
(EECs, REEs) in related (stable isotope analysis based evidence) items of the same trophic web from sediments and seawater to pack-ice and biotic components (e.g. criopelagic comunity, fish, South Polar skua, Adèlie and Emperor penguins); determination of lipid content of organism tissues.
Task 2 - ECC and REEs in the Ross Sea ecosystem: compartment transfer, evaluation of spatial and temporal trends of contaminants in sea-water and organisms by using data from this survey and data series from previous campaigns.
Task 3 - ECCs in DOM and criopelagic community: abiotic/biotic processes influencing circulation in sea-ice and under-ice environment and effects of DOM on contaminant mobility and ecosystem functional and structural diversity.
Task 4 - seabird energy expenditure and stress: correlate the contaminant levels in seabird blood to blood parameters (thyroid hormones and prolactin) to evaluate the ECC and REE impacts of exposure to contaminants.
Task 5 - comparison between polar areas: emerging contaminant distribution and fate in the Ross Sea and NE Greenland ecosystems. NE
Greenland shows similar characteristics to Antarctica, thus two case studies will be compared, thanks to the participation of the PI to the
international TUNU Programme: Arctic Ocean Fishes – Diversity, Adaptation & Conservation (2002-) that will provide samples and data.
Task 6- overall results: OU jointly activities during the two years research project will led to the statistical elaboration of the results from all the OUs, for their dissemination in educational, (lectures, seminars, educational publication, website) and scientific (international conference, publication in ISI journals) media.
Task 7 - PNRA and SCAR activities: answering to the Strategic Plan 2017-2019 established by the Italian National Commission for Antarctica, to some of the 80 high-priority scientific issues defined by he 1st SCAR Antarctic and southern Ocean Science Horizon Scan, and share results and expertise to the ImPACT SCAR Action Group and the Information Summary of the Antarctic Environments Portal.

The project is divided in 12 deliverables (D) describing the expected outputs; they will be achieved through the collaboration among the
four OUs and national and international collaborations.
D1) sample collection and report on 1st year activities at MZS - done
D2) definition of the iso-POP-scape (joint isotopic and pollution maps) for the Ross Sea
D3) overview of the sources, distribution, latitudinal, temporal trends, compartment interactions of emerging inorganic and organic compounds in the Ross Sea seabird trophic web in the light of human impacts and climate change; results of the relationships among environmental compartments, to assess the contaminant transport and distribution in the Ross Sea environment
D4) seabird energy expenditure (blood parameters) and stress; risk assessment (in abiotic and biotic matrices)
D5) DOM and criopelagic community: characterization of the dimensional fractions of DOM (colloidal and truly dissolved) in water column,
quantification of selected emerging contaminants in different samples (in collaboration with other OUs) and in DOM size fractions; estimation of biomass diversity in cryopelagic community (prey to predators) to understand the main processes governing contaminants mobility, the effects on biomass diversity and the abiotic/biotic DOM degradation processes
D6) final report and educational and scientific dissemination: preparation and submission of presentations at international conferences,
publication in international ISI journals, seminars, website, public events
D7) communication of data and results to the SCAR Action Group ImPACT and update of the Information Summary in the Antarctic Environments Portal.

The research results will bedisseminated to a professional scientific audience through publications inpeer-reviewed international journals with high impact factor, lectures andposters at international and national meetings and conferences. A website willbe also created for specialist and non-specialists audience. The activities andresults will be presented at University public science events (e.g. ResearcherNights, ScienzEstate etc) and also at University courses (i.e. Ecotoxicology ofremote areas, University of Siena; Environmental Analytical Chemistry – Organiccontaminants, University of Florence). Seminars will be organized for studentsand PhD students.