Marine traffic is an important noise contributor to the underwater soundscape. In addition to the growing marine traffic worldwide, the increase in both ship size and ship power tends to intensify the radiated noise, and thus the low-frequency noise level. Studies have shown that marine species can be impacted by the rapid growth of ambient noise levels. In particular, masking of communication or behavior changes in relation to noise exposure have been documented.

Shipping noise and its consequences on marine fauna are now monitored, and their evolution is of major concern for marine policies. Shipping noise modeling, based on Automatic Identification System (AIS) data is the most common approach to providing underwater noise levels at basin scales. Indeed, most ships are equipped with AIS transmitters, sending information concerning both the ship (ID, activity, length, etc.) and its navigation (position, speed, heading, etc.). This information is used to compute traffic density maps, and to model the ship’s radiated noise. The ambient noise is finally inferred by propagating noise sources in the environment.

In France, a first Covid-19 lockdown occurred from the 17^th of March to the 11^th of May 2020, reducing significantly the marine traffic. In particular, cruise ships, passenger vessels, vehicle carriers and containerships harbor callings have decreased by 27%, 13%, 7% and 2 % respectively in member states harbors from 2019 to 2020, according to the European Maritime Safety Agency (EMSA). This traffic decrease affected only specific categories of ships, and contributed to some extent to a decrease of the anthropogenic underwater noise.

This study aims to analyze the impact of the traffic density reduction due to the lockdown on the shipping noise in the occidental part of the Mediterranean Sea by use of AIS datasets from 2019 and 2020, and eventually to discuss the potential benefit of traffic density reduction as a mitigation measure.

How to cite: Lajaunie, M., Ollivier, B., Ceyrac, L., Dellong, D., and Le Courtois, F.: Impact of Covid-19 lockdown on shipping underwater noise in the Mediterranean Sea, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12329, https://doi.org/10.5194/egusphere-egu22-12329, 2022.

The Arctic is undergoing fast paced changes due to the amplified global change drivers and their effects on biophysical processes there. In particular, ocean acidification (OA) and global warming are likely to affect marine ecosystem processes with severe consequences for livelihoods that depend on natural resources from these ecosystems. Here, we examined those combined effects by running a series of scenarios of OA and warming on an end-to-end ecosystem model (Atlantis) parameterized for the waters around Iceland, and compared those to a baseline projection with no warming and OA. We assessed the resulting population dynamics for a subset of species in Icelandic waters that are important for their economic (catch value), social (number of participants in fisheries), or ecological (keystone species) importance. We used literature-derived values for the sensitivity of these species and functional groups to OA and warming. We show that the responses to OA and warming vary by species and trophic levels; generally, under warming and acidification scenarios several planktonic groups and forage fish improved their populations, while benthic groups and predatory fish populations decreased. When examining the combined effects of OA and warming under current conservative harvest rates for the largest catch-value species, Atlantic cod, we find that surprisingly this population remains stable, even when considering the strongest acidification and warming. However, when the model projects reductions in biomass of Atlantic cod, other species in the ecosystem increase likely due to reductions in competition and predation. Our results highlight possible cascading effects through trophic networks on both ecological and socio-economically important species, and the need for more ecosystem modeling of global change drivers to find such effects.

How to cite: Oostdijk, M., Sturludóttir, E., and Santos, M.: Ocean Acidification and Warming effects on important Socio-Economic and Ecological Species in a Sub-Arctic Marine Ecosystem, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7948, https://doi.org/10.5194/egusphere-egu22-7948, 2022.

Investigating responses of marine viruses to the variation of climate change factors are essential to understanding the effect of global climate change on viral dynamics in the marine microbial food web and virus-mediated biogeochemical cycle. However, there are few studies on the effect of global warming on in situ viral communities in the tropical ocean. Therefore, we performed an experiment to explore the effect of warming on the dynamics of in situ viral community in South China Sea. Interestingly, as a tropical marine viral community, the production and decay rates were still increased by warming, and the balance between production and decay seemed to be broken, resulting in more accumulation of viral particles. As two subpopulations of marine viruses, low-fluorescence viruses may be more sensitive to warming than high-fluorescence viruses. In general, our study indicated for the first time that warming will accelerate the turnover of viruses in surface water of the tropical ocean, which may have positive effects on the efficiency of the BP and MCP.

How to cite: Wei, W., Xie, L., Jiao, N., Luo, Y., and Zhang, R.: Global warming potentially enhanced both the viral production and decay in a tropical ocean, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2931, https://doi.org/10.5194/egusphere-egu22-2931, 2022.

The basic bacterial ecology and diversity was investigated in five running water systems of Southern New Caledonia (including a former Cr/Co mine). These running waters were characterized by potential P-limitation and high concentrations of Ni, Fe, Mn, Cr and Co. The low concentrations of dissolved organic carbon, bacterial and viral abundance, bacterial production and growth efficiency support the characterization of the running waters as oligotroph to ultraoligotroph. Despite these similarities, there were strong differences (<50% similarity) in bacterial community composition between some habitats based on 16S rRNA gene and denaturing gradient gel electrophoresis (DGGE) fingerprints (e.g. the Cr/Co) mine). The high coverage of sequenced DGGE bands found for Betaproteobacteria is typical for freshwater systems, however, we found also a strong representation of Gammaproteobacteria. Indeed the three bands found at all stations were related to Limnohabitans (Comamonadaceae) and Alteromonadaceae. Strong differences were also found between the free-living and the attached bacterial fraction with Gammaproteobacteria dominating in two systems. A higher representation of Gammaproteobacteria seems typical for metal-rich freshwater habitats. Consistent with fresh water habitats, majority of phylotypes detected in the sediment was affiliated to proteobacteria. Also, none of the sequences showed a 100% identity with data bases, and 10 of the 22 and 2 of the 23 sequences had similarities higher than 97% in the freshwater and sediment. This could indicate specific adaptations of the community composition either due to the high metal concentrations or due to the geographical isolation of the New Caledonia. 

How to cite: Weinbauer, M., Motegi, C., Migon, C., and Mari, X.: Bacterial abundance, growth and community composition in oligotrophic, metal-rich running waters of Southern New Caledonia, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5677, https://doi.org/10.5194/egusphere-egu22-5677, 2022.

Climate change drives oceanographic mechanisms at the global level and affects the functioning and structure of marine ecosystems by inducing shifts in species and habitats distribution. The coralligenous outcrops of the Northern Adriatic Sea (Eastern Mediterranean basin) are listed among the habitats of priority for conservation in the Habitats Directive (92/43/EEC) and in the Marine Strategy Framework Directive (2008/56/EC) for their importance as biodiversity hotspots and ecosystem services providers and are recognized to be needy of protection also due to their vulnerability to climate change impacts. This study aims at investigating how environmental variables predicted in future climate change scenarios could affect the distribution and composition of the coralligenous benthic assemblages in the northern Adriatic Sea, to inform management and conservation strategies in the area. A cutting-edge approach was adopted through the application of two predictive models (Maxent and Random Forest) in association with oceanic circulation modeling (ROMS) to deliver the most reliable projections. The present coralligenous habitat distribution and the different habitat typologies (based on the epibenthic assemblages structure inferred from literature) were correlated with historical (consisting in temperature, salinity, velocity, light, nitrogen and phosphorus concentration) and climate change scenario RCP 8.5 (temperature, salinity, velocity) variables in order to provide estimates of possible distribution shifts. Predictive maps showing the degree of habitat suitability across the basin were provided together with a potential shift in the structure of the associated communities. Predictive models are powerful decision-support tools (DSTs) to inform conservation strategies, and in this study they are applied to support the identification of new potential areas of conservation priority in the Northern Adriatic basin, where coralligenous outcrops will be still present in the future despite climate change. We emphasize the relevance of applying DSTs to help undertake science-based actions for conservation purposes in the face of future climate change effects on marine ecosystems.

How to cite: Vitelletti, M. L., Manea, E., Bongiorni, L., and Bonaldo, D.: Modelling coralligenous habitat distribution in the Northern Adriatic Sea in a severe climate change scenario, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9652, https://doi.org/10.5194/egusphere-egu22-9652, 2022.

Sediments across Lagos Lagoon have been sampled and analyzed to investigate the extent and distribution of Potentially Toxic Elements (PTEs). The bioavailable fraction of PTEs have been evaluated to explore the relationship between PTE concentration and the spatial distribution, composition, abundance, and species richness of benthic foraminifera biotas. The sediments have been found to show a wide range reflecting a diffuse contamination, where Contamination and Enrichment Factor suggest low to extremely polluted sediments. Our survey of the benthic foraminifera inhabiting Lagos Lagoon revealed diverse assemblages of benthic taxa, species-specific distribution patterns, gradients of species richness and abundance, and a disjunct distribution of agglutinated and hyaline-perforate/porcelaneous taxa along a pronounced salinity gradient. All PTE total concentrations have been shown to positively correlate with mud and Total Organic Carbon (TOC) and two of the most abundant agglutinated taxa, Ammotium salsum, and Trochammina sp. 1, according to our correlation matrix analysis. Moreover, both species display significant positive correlations with Cr_F4-Co_{F2-F3-F4-total}-Cu_F4-total-Ni_F3-F4-total-Al_F4-total-Fe_F3-F4-total-Zn_F3-F4-total. On the other hand, both foraminifers correlate negatively with Pb_F4-Se_F3-Se_total. The overall significant positive correlation of these PTEs suggests that they behave as micronutrients when complexed with organic matter. No significant positive correlation with none of the PTEs in any fraction was found for neither species richness nor for the most abundant hyaline perforate species (Ammonia aoteana). Some PTE fractions were found to correlate either positively or negatively with individual foraminifera species, suggesting that they function as either micronutrients and/or stressors. The resulting Contamination Factor of the PTE total concentrations shows that only a few sample sites can be classified as “moderately” polluted for Cr, Zn, and Cu, and that all sampled sites are classified as “highly polluted” for Se. The highest concentrations for Cr, Cu, Ni, and Zn were found towards the industrialized western part, an area that is characterized by moderate to high diversity but low abundances of benthic foraminifera.

How to cite: Sariaslan, N., Martínez-Colón, M., Council, I. S., Kolawole, T. O., Langer, M. R., and Fajemila, O. T.: Correlating Contamination Levels of Potentially Toxic Elements with Foraminiferal Distribution Patterns in Lagos Lagoon (Nigeria), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7689, https://doi.org/10.5194/egusphere-egu22-7689, 2022.

The coastal marine environment is a key area for humans with more than 40% of the European population concentrated on coastal regions. Coastal areas are densely populated and often host industrial activities which have the potential to generate pollution.

Anthropogenic impacts overlap with climate change that can amplify the effects of pollution on marine ecosystems.

A modern strategy of investigation of the coastal marine environment requires the development of remote sensing methods useful to acquire information on numerous characteristics of marine ecosystems. Particular attention is given to the mapping of benthic ecosystems which are capable to record the effects of pollution events and could respond with changes in their composition and community structure, but also in the spectral signature as already studied for some algal species. Importance is given to the selection of new bioindicators to assess the ecological quality of benthic biocenosis of coastal marine ecosystems through remote sensing observations, integrating platforms data at different spatial scales. Moreover, once the target species have been identified, it is possible to interpret variations in the spectral response that allow to identify and quantify the impacts of pollutants that are released into the sea directly or indirectly by human activities.

This work is part of the STOPP project (Strumenti e Tecniche di Osservazione della Terra in Prossimità e Persistenza), funded by ASI (Agenzia Spaziale Italiana), and aims to (I) map seagrasses and macroalgae species applying remote sensing methodology (e.g., Leaf Area index – LAI); (II) select target species that can respond to certain pollutants through variations in the spectral signature; (III) develop an innovative methodology for the monitoring and mapping of marine bioindicators by detecting "target wavelengths" caused by the impact of chemical pollutants on seagrasses and macroalgae species.

How to cite: Varini, F., Madonia, A., Piermattei, V., Piazzolla, D., and Marcelli, M.: Development of innovative remote sensing techniques and tools for mapping marine bioindicators and their potential responses to specific anthropogenic pollutants, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8032, https://doi.org/10.5194/egusphere-egu22-8032, 2022.

Low head Pumped Hydro Storage (PHS) has been considered an opportunity for energy storage since the rise of wind and solar energy development in Europe. The study of environmental aspects (siting, fish friendliness, and land use) therefore plays an important role in the ALPHEUS project (Augmenting Grid Stability Through Low Head Pumped Hydro Energy Utilization and Storage), which is a project funded by the European Union’s Horizon 2020 program. The principal aim of the project is to improve reversible pump/turbine (RPT) technology to make pumped hydro storage economically viable in coastal environments. Within the project, one of the objectives is to evaluate the impacts on the coastal marine environments of a low head pump hydro device at a preliminary level. The area designated for the implementation of the prototype test site is in the North Sea. The project will evaluate a variety of measures to either prevent fish from entering machinery or maximize the survival rate of fish passage.

This study is part of the ALPHEUS activities that investigate environmental aspects, and, focuses on the production of a protocol for PHS with the identification of the characteristic elements of each test site as part of the application of the MSFD (Marine Strategy Framework Directives) principles. It is, therefore, possible to evaluate in advance which environmental components are potentially affected by seawater PHS devices. The descriptors that are affected by PHS interactions are D1, D3, D6, D8, D11. D1 and D3 descriptors are focused on biodiversity and on commercial fish health, for this reason, an in-depth study of the effects on fish is required. Considering this, it is applied an innovative methodology for the assessment of potential impacts, injuries, and mortality rates on selected fish species. Fish friendlessness is estimated using software called Biological Performance Assessment (BioPA) that assimilates hydraulic field data, Computational Fluid Dynamics (CFD) results, and laboratory fish-injury studies. This tool gives the probabilities that fish will encounter hazardous conditions during passage through specific regions of the turbines and the impacts induced by hydrodynamic stressors.

How to cite: De Luca, A., Scanu, S., Peviani, M., Marcelli, M., and Miccoli, A.: Study of the effects of low head Pumped Hydro Storage technology on coastal environment and fish passage, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5842, https://doi.org/10.5194/egusphere-egu22-5842, 2022.

Red tide has always been an environmental issue with global concern. A Noctiluca scintillans red tide and a Mesodinium red tide occurred successively in northern Yellow Sea, China, where is important shallow sea aquaculture base, in October 2019. The initiation of the red tides was the result of both biotic (e.g. food) and abotic factors (e.g. currents and nutrients availability). The maximum N. scintillans and Mesodiniium abundance reached 124.92 ± 236.84 × 10³ cells/ L and 1157.52 ± 1294.16 × 10³ cells/L respectively. The fast growth of N. scintillans was due to increasing abundance of phytoplankton after the harvest of cultured scallops. Appropriate temperatures also increased the growth of N. scintillans. Water dynamics played a key role in the formation of the red tides. The steady southward current from the Bohai Sea and northern Yellow Sea was instrumental in the accumulation of N. scintillans along the coast. The accumulation of Mesodinium was attributed to the neap tide and weak current on October 19 to 22. Water turbulence from a strengthened current on October 24 eventually destroyed the Mesodinium red tide. The red tides significantly redistributed the nutrients in the red tide patches and regulated the dominant species in phytoplankton community. Our study illuminates the influence of physical-biochemical coupling processes on red tides, and suggests that ocean dynamics such as currents and tidal factors deserve more attention when considering the ecosystem health problems of coastal zones.

How to cite: Zhang, W., Dong, Z., Zhang, C., Sun, X., Hou, C., Liu, Y., Wang, L., Ma, Y., and Zhao, J.: Influence of Physical-biochemical Coupling Processes on the Noctiluca scintillans and Mesodinium red tides in October 2019 in northern Yellow Sea, China, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2103, https://doi.org/10.5194/egusphere-egu22-2103, 2022.

The effects of bloom-forming gelatinous zooplankton (hereinafter jellyfish) on the biogeochemistry of marine ecosystems are still largely unknown. Due to their high reproductive output and fast growth, some jellyfish form blooms when conditions are favourable, reaching high biomass within a short period of time. As these blooms decay, often abruptly, massive amounts of jellyfish organic matter (jelly-OM) are released to the surrounding system, causing perturbation to the ambient organic matter pool, hence re-structuring microbial community and thus affecting functioning and biogeochemical state of the marine ecosystem. Due to its high protein content and low C to N ratio jelly-OM supports rapid growth of opportunistic microbes, exhibiting high growth efficiency, with important implications for the re-cycling of jelly-OM. However, the C and N content of jelly-OM may vary and changes of jelly-OM stoichiometry can have important implications for dynamics of its surrounding system, in particularly, its end-consumers, microbial communities, who are true drivers of marine biogeochemical cycles. Thus, understanding the factors determining the chemical composition of jelly-OM is important to better understand the interaction between microbes and jelly-OM, which will allow us to accurately incorporate jelly-OM into biogeochemical budgets of a system. Hence, we analysed the biometry, chemical composition and fecundity of invasive ctenophore Mnemiopsis leidyi from the northern Adriatic, throughout their blooming season, from August until end of October 2021. Temperature decreased from around 25°C in August to around 17°C in October, while at the same time salinity increased from 34 to 38. During the period of M. leidyi bloom, concentration of Chl a increased from around 0.7 µg L^-1 in summer to 1.2 µg L^-1 in autumn. In total we conducted 6 fecundity experiments, each time using 5 individuals exhibiting similar biometric characteristics. The C to N ratio of ctenophores, with an average wet weight of 24.3 ± 7.8 g, was 4.5 ± 0.2 and did not exhibit changes over the studied period. The egg production ranged from 0 to 638 eggs per individuum, with 93 ± 12% hatched within first 48 hours. There was no clear correlation between egg production and C to N ratio of individuum. However, we did observe temperature effect; egg production was higher during periods of high temperatures (21-25°C) and hatching was lower and slower at lower temperature (in October, at 17°C). We observed an increase of individuals infected with parasites over the time of bloom development, which also correlated with lower egg production and percentage of hatched eggs. Our results importantly contribute to our understanding of the dynamics of jelly-OM as largely overlooked pool of organic matter, especially for coastal marine microbiomes.

How to cite: Tinta, T., Rečnik, K., Klun, K., and Malej, A.: The importance of bloom-forming Mnemiopsis leidyi for the biogeochemistry of invaded coastal marine ecosystems, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1646, https://doi.org/10.5194/egusphere-egu22-1646, 2022.

Zooplankton are among the most abundant animals in the ocean and are keystone species linking primary producers to higher trophic levels. Microplastics (MP) are becoming ubiquitous contaminants in the ocean that may spread through water layers from surface to bottom in all oceanic regions and be ingested by zooplankton. MP ingestion by zooplankton may lead to deleterious effects that may spread up the food-web to ultimately impact entire ecosystems. However, in situ quantification of MP contamination in the water and the biota is complex. As a result, global impacts of MP on zooplankton remain largely unknown. In this study, we use a global coupled physical-biogeochemical model providing realistic nutrient and plankton cycling, augmented with a 3D module for the representation of MP, in order to calculate the first global estimates of zooplankton exposure to MP. Results indicate that water contamination by MP is highest in the surface of subtropical gyres and coastal areas close to major MP sources, while sinking MP accumulates at the bottom of coastal zones close to their sources. We estimate zooplankton exposure to MP based on water concentrations of MP, particles and plankton and on zooplankton grazing rate. We found 2 main drivers favouring high zooplankton exposure to MP: 1) high water MP contamination, which increases zooplankton ingestion risk, even at low grazing rates and 2) intense grazing activity in productive regions increasing MP exposure even in moderately contaminated waters. Finally, despite low seasonal variability in [MP], buoyant MP may be seasonally transported to the mesopelagic waters (between 100and 1000m) by convective currents. Consequently, re-stratification of surface waters may lead to highest MP concentration in surface coinciding with planktonic blooms, thus periodically increasing contamination risk.

How to cite: Richon, C., Gorgues, T., Paul-Pont, I., and Maes, C.: Constraining zooplankton exposure to microplastic at the global scale: results from a new coupled physical-biogeochemical model (NEMO/PISCES-PLASTIC), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1455, https://doi.org/10.5194/egusphere-egu22-1455, 2022.

It is generally believed that the enhancement of phytoplankton appears only in shallow and intermediate depth seamounts, while the phenomenon has also been observed in some deep seamounts by satellites recently. To figure out what effect do deep seamounts have on phytoplankton and the relevant mechanisms, the phytoplankton biomass and community on the Kocebu Seamount (depth: 1198 m) were studied. The results showed that high Chl a patches (> 0.2 mg·m^-3) were mainly distributed within 20 km of the peak, and both nitrate and orthophosphate were obviously uplifted at the peak. The physical data indicated the uplifted of nutrients could be caused by the internal tides, which generated by the interaction of topography and tide. This is the first time that the promotion of phytoplankton was observed in situ on a deep seamount, and this study expounded relevant mechanisms and suggested that the ecological functions of deep seamounts may have been previously neglected.

How to cite: Dai, S.: Seamount effect of a deep seamount on phytoplankton in the tropical western Pacific, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6727, https://doi.org/10.5194/egusphere-egu22-6727, 2022.

Marine areas facing the river mouths are characterised by high primary and secondary production. Fluvial inputs affect primary production both directly with high nutrients inputs and indirectly through the interaction both with offshore water masses and the distribution of benthic communities.

The study area includes the mouth of the Tiber river which, with a length of 405 km and a catchment area of 17375 km², represents the main river in central Italy.
The area affected by the Tiber plume has a wide extension being conditioned by strong dynamics forcing. It extends towards the open sea up to the limit of the continental shelf and along the coast in the entire physiographic unit between Capo d'Anzio and Capo Linaro, although fine particulate can reach up to the promontory of Monte Argentario.

The main characteristics of the inputs behaviour are mainly modulated by the dynamic processes: wave currents, general circulation and tidal currents as well as geomorphological factors as bathymetry and shoreline.

Accordingly, the abundance of phytoplankton biomass is modulated by the presence of fluvial inputs and consequently by the dynamics of the meteo-oceanographic and climatic characteristics of the area.

The main objective of this work is to analyse the influence of the Tiber river on the central Tyrrhenian Sea, also considering the influence that the basin-scale circulation has on the coastal water masses.

Satellite data do not allow a detailed analysis of this complex phenomenon, limiting the observation field at the surface layer, so the area was characterised by a series of oceanographic campaigns to analyse the interaction between coastal, transitional and offshore waters.

The dynamic processes that contribute to the primary production modulation in space and time were also analysed using high resolution numerical models developed for the study area and nested into the macro and mesoscale models for the Tyrrhenian and Mediterranean basins. The models were validated using data of the existing observing system which includes other measurement platforms at different spatial and temporal scales, in addition to the oceanographic campaigns.

In order to study this high variability area the sustainability of an extended observing system and its functioning for the operational tools (development and validation of mathematical models) is fundamental.

The international scientific community (Oceanobs 2019, GOOS) strongly promotes the necessity of integrated coastal observing systems based on cost-effective and advanced technologies both to carry out new measurements and to reduce the costs of existing oceanographic instrumentation.

For this reason the future development of this work is the integration of autonomous observation platforms (Glider and ASV) and cost-effective technologies for the extention of the existing the observing spatial and temporal capacity.

How to cite: Piermattei, V., Madonia, A., Coppini, G., Fersini, G., and Marcelli, M.: Analyses of Tiber river plume dynamics and the interaction with phytoplankton primary production, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9398, https://doi.org/10.5194/egusphere-egu22-9398, 2022.

As an emerging pollutant, the presence of microplastics in marine organisms has been concerned increasingly. Shellfish, which are both economically and ecologically important, are of particular concern. In this study, we investigated the microplastic pollution in wild and farmed oysters ( Crassostrea gigas ) and clams ( Ruditapes philippinarum ) in the Jiaozhou Bay, China, for the first time. We found the microplastic pollution in shellfish in Jiaozhou Bay was at a moderate level. The abundance of microplastics in shellfish ranged from 0.16 to 12.09 items/g (wet weight, ww) or 1 to 9 items/ind. The average abundance of the ingested microplastics was 1.21 items/g (or 2.17 items/ind.) in all shellfish, 1.51 items/g (or 2.00 items/ ind.) in clams and 0.92 items/g (or 2.34 items/ind.) in oysters. The abundance of microplastics in clams was significantly higher than that in oysters. Most microplastics (92.97%) were fibers, followed by fragments. The predominant color of the microplastics was black (42.97%), followed by blue, transparent, and red. Cellophane and polyethylene terephthalate (PET) dominated the microplastic composition. According to shellfish consumption, it can be inferred that the average microplastic consumption through Chinese diet is 1.27×10³ items per capita per year.

How to cite: Zhang, K.: Abundance and characteristics of microplastics in shellfish from Jiaozhou Bay, China, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6691, https://doi.org/10.5194/egusphere-egu22-6691, 2022.

Local and global anthropogenic pressures due to climate change and to local uses and activities are exerting significant cumulative impacts to greater extents of the oceans and seas. Coastal ecosystems are particularly threatened by the intensity and coexistence of several marine uses and pressures, including sewage and urban constructions, tourism, ship traffic, fisheries and aquaculture. Assessment of pressures and the identification of mitigation measures are key urgent actions, as already highlighted by the EU Marine Strategy Framework Directive and the United Nations Sustainable Development Goal 14. The aim of this work, developed within the Interreg-Med project SHAREMED, is to systematize existing knowledge on threats and pollution, including those of transboundary origin, for long term strategies and common action marine spatial planning, jointly developed with stakeholders. The quest is to assess coexisting environmental threats, and their propagation in space and time, at proper spatial and temporal scales, according to the type and action of each stressor (i.e. global vs. local). Cumulative pressures are tackled within a dedicated Atlas comprising three sub-basinsins of the Mediterranean Sea: the North Adriatic Sea, the Sicilian Channel and the North-Western region. The Atlas integrates information generated at the best available resolutions by 1) in-situ sampling, 2) remote observations, 3) numerical models, and 4) focusing on target ecosystems and habitat forming species. These sub-basins are subjected to multiple local and larger scale (e.g. climate) pressures that propagate in space and time, and across political boundaries, that need to be addressed through coordinated actions, based on evidence-rooted common understanding. Interactions with relevant Stakeholders, solicited through an online survey, and meetings, were used to select target ecosystems and to identify the key relevant pressures. The Atlas is based on open-access databases and portals, literature reviews and from ad-hoc model simulations concerning marine heatwaves, ship traffic, oil pollution, marine litter and fishing efforts. We will present the main preliminary results and needs and gaps in observations related to marine ecosystems threats.

How to cite: Melaku Canu, D., Zunino, S., Bendoni, M., Brandini, C., Čermelj, B., Drago, A., Faure, V., Galea, A., Galiana, S., Garcia, X., Grenz, C., Lapucci, C., Ličer, M., Lipizer, M., Mavrič, B., Perna, M., Previati, M., Queirós, L., Ruitton, S., and Viure, L.: Mapping human impacts to support sustainable uses of marine ecosystems in the Mediterranean sea, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9926, https://doi.org/10.5194/egusphere-egu22-9926, 2022.

The north sea is a highly productive area, both biologically and for a variety of economic activities. It is also undergoing great change; anthropogenic usage is changing with Oil and gas activities ramping down whilst offshore wind installations are increasing, all against the increasing impact of climate change. For oil and gas structures there is an active debate as to the positive or negative ecosystem effects of different decom​missioning strategies for structures (e.g. removal, topp​ling). Whilst the effect of different options have been ​extensively studied at the level of individual structures, it is necessary to consider them in a basin wide context and ​in combination with the effect of other contemporary pressures.

Here we use coupled physics-biogeochemistry models (GOTM-ERSEM, FVCOM-ERSEM and FVCOM-PyLAG with specific adaptions for man-made structures to understand the possible scope and magnitude of effects on the north sea ecosystem for different decommissioning scenarios of oil and gas structures (removal, toppling, leaving intact). Specifically we look at the utilisation of structures by colonising organisms, the effects of trawling exclusion, and changes to connectivity. We also consider these with the addition of other man made structures (shipwrecks and wind farms) and under a future climate scenario.

How to cite: Bedington, M., Lessin, G., James, M., and Somerfield, P.: Assessing ecosystem effects of changes to man​-made infrastructure in the ​North ​Sea, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11984, https://doi.org/10.5194/egusphere-egu22-11984, 2022.

Bottom trawling, a fishing practice that entails the dragging of heavy fishing gear along the seafloor, is one of the most direct human interferences with the marine environment. Bottom trawling is known to resuspend a large amount of sediment, thereby releasing nutrients, organic carbon and contaminants to the water column. However, the large-scale effects of bottom trawling on sediment and carbon fluxes have remained difficult to quantify. We aim to quantify these fluxes through numerical modeling of bottom trawling activity in the North Sea. A particular focus is put on muddy areas rich in organic carbon, as chronic bottom trawling could inhibit their function as carbon sinks. By combining a three-dimensional, coupled hydrodynamics and sediment transport model with data of trawling effort in the study area, we parametrize the resuspension caused by bottom trawling on the basis of individual vessels and the subsequent transport of resuspended material by ocean currents. Results show that bottom trawling has potentially large impacts on the inventories and fluxes of suspended matter and organic carbon of the North Sea. The results may be useful in determining areas worthy of protection in the context of marine spatial planning.

How to cite: Porz, L., Yilmaz, R., Kossack, J., Zhang, W., and Schrum, C.: Modeling the impacts of bottom trawling on the sediment and particulate organic carbon distribution of the North Sea, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-13116, https://doi.org/10.5194/egusphere-egu22-13116, 2022.

Anthropic impacts mainly affect the coastal areas by the building of ports and the changing of courses of rivers. These activities can potentially interact with the natural coastal dynamics which are ruled by complex climatic, hydrodynamic and sedimentary processes.

Preliminary studies on the environmental impacts are increasingly necessary because the potential disturbances could affect natural coastal system at different spatial and temporal scales. Hydrodynamics and sediment transport models use specific equations to be basing on depict actual phenomena and expect future scenarios.

The present study aims to predict the environmental impact of the building of the new port of Fiumicino (central Latium coast, Italy), in a stretch of coast extended from Capo Linaro to Capo Anzio interested by Tiber River dynamic. Using numerical models, we have been able to give a prediction of the coastline evolution before and after the port construction, with particular attention to the sediment dynamic in the coastal areas affected by high ecological values such as nurseries, seagrass meadows and coastal dunes.

The coastal morphology changes have been investigated using the LITPACK (Littoral Transport and Coastline Kinetics) module of the software MIKE0 developed by the Danish Hydraulic Institute (DHI), a one-dimensional model which describes the dynamic processes that determine the shoreline evolution. The model has been fed with morphology and granulometric data collected along the study area in the 1990, as well as the wave parameters achieved by the WAM model included in COPERNICUS catalogues. LITPACK model has been validated using short- and long-term simulations, comparing the results of the historical analysis of the coastline in the period 1990-2021.

Finally, future scenarios have been carried out to investigate the contribution of the effects of the new port building on the morphological coastline variation.

How to cite: Madonia, N., Bonamano, S., Piazzolla, D., Scanu, S., and Marcelli, M.: Sediment Transport Modeling to Forecast Coastline Changes due to New Port of Fiumicino (Central Latium Coast, Italy), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8500, https://doi.org/10.5194/egusphere-egu22-8500, 2022.

The potential effects of anthropic pressures on the coastal marine environment are difficult to predict due to the high spatial and temporal variability of the physical and biological processes occurring in the coastal area. To overcome this issue, an innovative coastal observing and modelling system has been implemented along the Latium coast (Italy). The core of the modelling suite is composed of the unstructured-grid hydrodynamic SHYFEM and wave WW3 models to allow to compute the temperature, salinity, current velocity, water levels and wave parameters, seamlessly from the open sea to the coastal waters. The hydrodynamic and wave results were then used within process-oriented models (such as XBEACH, PTM, Leeway Lagrangian particles models) to analyse morphological changes, sediment dynamics and pollutant dispersion in the coastal, riverine and near-port areas.

In this work, the modelling suite was used to investigate the potential effects on the soft-bottom benthic communities due to the realization of the new port of Fiumicino, located in the coastal zone affected by the Tiber river dynamic. The coastal dynamic processes along the study area were simulated using different weather conditions, before and after the realization of the new harbour. Hydrodynamic and wave model performance was evaluated using in-situ and remote sensing observations carried out by high-resolution satellite imageries and traditional and innovative in-situ platforms. Finally, the model results were compared with the abundance and composition of the benthic community that was analysed in 25 stations, between 2 and 30 m depth.

How to cite: Bonamano, S., Federico, I., Mancini, E., Causio, S., Piermattei, V., Piazzolla, D., Scanu, S., Jansen, E., Coppini, G., Fersini, G., and Marcelli, M.: Numerical models to evaluate the potential effects of new port realization on coastal marine ecosystems , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11312, https://doi.org/10.5194/egusphere-egu22-11312, 2022.