Understanding mercury (Hg) dynamics in an estuarine system is vital because of its potential toxicity to the ecosystem. India is the second largest producer of atmospheric Hg, and the dynamics of Hg are poorly understood in tropical estuarine systems. This study describes the distribution, speciation and mobility of Hg in a monsoon-fed tropical estuarine system in India (Mandovi estuary, East coast of India) during dry period (November-March) when the pollutants stay for a long time within the estuary due to negligible river discharge.

This study presents the impact of changing physicochemical parameters of water column (such as pH, dissolved oxygen, salinity) and sediment [such as texture, sedimentary organic matter (SOM), molar carbon to nitrogen ratio and chemical characterisation of SOM] on distribution and speciation of Hg in the surface sediments,  porewater and water column along the length of the estuary (from upstream to downstream). There was a significant increase in concentration of sedimentary methylmercury (MeHg)(a neurotoxin) with an increase in total sedimentary Hg concentration in the estuary. However, concentration of sedimentary MeHg was found to decrease with increasing concentration of SOM depend on the nature of SOM. Results from an equilibrium-based model (Visual MinteQ) showed that a significant concentration of Hg was associated with type-II fulvic acid, and reduction of Hg(II) was more in presence of type-II humic acid.

This study showes that the reduction and methylation process of Hg control Hg distribution in the study area, and estuarine sediment is one of the primary sources of dissolved Hg in the water column.

How to cite: Jayachandran, S. and Chakraborty, P.: Dynamics of mercury in a tropical estuarine system during dry season, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-839, https://doi.org/10.5194/egusphere-egu23-839, 2023.

The Mar Menor coastal lagoon (Spain) is a critical ecological and socioeconomic ecosystem and the first in Europe to be granted rights of personhood. However, pollution from past and present activities such as mining, agriculture, urbanization, and tourism threatens its health and ecological stability. Previous research has shown the importance of metal contamination in the lagoon and its link to nearby mining activities, but little consideration has been given to historical changes in this industry and in other potential metal sources. In this work, metal concentrations have been analyzed in 12 sediment cores dated with ²¹⁰Pb, allowing the reconstruction of the recent (last ~150 years) metal contamination in the lagoon. The main metal sources have been identified by using multivariate statistical methods. Metal contamination from mining activities (point-source pollution) peaked in the mid-20th century, whereas nonpoint-source metal contamination reached its highest level in more recent decades. Despite the current decrease in metal deposition trends, concentrations in surface sediments still exceed sediment quality and ecotoxicological thresholds in areas close to former mining sites. Therefore, they need to be considered in future management strategies, which should also include the evaluation of sources and processes that are still supplying them to the lagoon.

How to cite: Alorda-Montiel, I., Rodellas, V., Arias-Ortiz, A., Rodríguez-Puig, J., Alorda-Kleinglass, A., Green-Ruiz, C. R., Diego-Feliu, M., Masqué, P., Gilabert, J., and Garcia-Orellana, J.: Centennial scale reconstruction of metal pollution in Europe's largest saltwater lagoon., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12312, https://doi.org/10.5194/egusphere-egu23-12312, 2023.

Halogenated natural products are organic compounds produced by marine bacteria and other marine organisms, as well as created anthropogenically through water chlorination and production as industrial compounds. These compounds can exhibit toxicity, bioaccumulate in the environment, and perform important roles in the regulation of the tropospheric and stratospheric ozone. To date, these compounds are understudied, particularly in Arctic and mid-latitude systems, with limited global data or understanding of spread. This project will share data on both di- and tri- bromoanisoles and bromophenols from the Western Arctic collected on a May-June 2021 cruise in the Beaufort and Chukchi Seas, as well as data collected from the mid-latitude estuary of Long Island Sound during 2022. These data help to close the gap in measurements of HNPs and inform future studies.

How to cite: Shipley, E., Vlahos, P., and Bidleman, T.: Detection and Quantification of Brominated Natural Products in Arctic and Mid-Latitude Coastal Air and Waters, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16773, https://doi.org/10.5194/egusphere-egu23-16773, 2023.

In the current global environmental problems, marine plastic pollution, ozone depletion and ocean acidification are included. With the development of research on microplastics, we have obtained important understandings on the temporal variation of the spatial distribution characteristics and the spatial variation of the temporal distribution characteristics of microplastics in China’s coastal waters. However, due to the complexity of microplastics features, the study of microplastic sources is in a relatively preliminary stage. Based on topographic features and chemical composition, an integrated index for microplastics complexity (MCI) was developed, and was applied in reflecting microplastics complexity in different media in Jiaozhou Bay. We compared the differences in microplastic complexity in wastewater treatment plants (WWTPs) and seawater, sediments and biota by in Jiaozhou Bay. MCI range from 0.35 to 57, with the average of 0.49 in wastewater in WWTPs. The MCI in zooplankton, which was 0.3 in average. The MCI in zooplankton is rather lower than that in the seawater, as zooplankton are so small as not to ingest large size particles of microplastics. The MCI of benthic shellfish was 0.46, which was higher than that in zooplankton, indicating that the complexity of microplastics in benthic shellfish were higher. The results of the study suggest that the value of MCI can be used for quantitative analysis of microplastic source apportionment. The MCI in wastewater in WWTPs, seawater, sediments, shellfish, and zooplankton showed the complexity of microplastic contamination in each phase and the connection between different media. Quantitative source apportionment is continuing to further promote the accomplishment of goal 14.1 in SDGs and decision support.

How to cite: Zheng, S., Sun, X., and Zhang, K.: Characteristics of microplastics in different media in Jiaozhou Bay, China, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5101, https://doi.org/10.5194/egusphere-egu23-5101, 2023.

Rivers are among the main sources of marine litter, especially for semi-isolated sea areas with high population and intense economic activity. The semi-isolated Black Sea located in the Eastern Europe is one of the examples of such areas, which watershed basin is under high anthropogenic pressure. In this study, we report the results of first long-term monitoring program of floating litter at several rivers inflowing to the northeastern part of the Black Sea. We describe the main characteristics of registered marine litter including the distribution of its type and size. Based on the obtained results, we reveal the relation between river discharge rate and the litter flux for the considered rivers. Using this relation extended to all rivers of the study area, we assess the total annual flux of riverine litter to the northeastern part of the Black Sea.

How to cite: Pogojeva, M., Korshenko, K., and Osadchiev, A.: Riverine Litter Flux to the Northeastern Part of the Black Sea, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-517, https://doi.org/10.5194/egusphere-egu23-517, 2023.

Beach wrack is defined as any material washed ashore by wind and wave actions plays a vital part in coastal ecosystems: it fosters dune formation and prevents beach erosion at land, provides food and shelter to beach fauna, both in and off the water. Nevertheless, it is often seen as nuisance and therefore removed at recreational beaches. So far, no complex data has been retrieved regarding the decay of beach wrack when left at the beach and in the shallow water.
To gain insight into the decomposition processes of beach wrack local seagrass of the species Zostera marina was chosen as prime example species and vital part of beach wrack at the southwestern German Baltic Sea coast at the island of Poel. In different seasonal experiments, seagrass was filled into white and black litterbags. In another experiment, seagrass in white litterbags was left in the shallow water until total disintegration of biomass. Sampling was conducted in regular intervals. The seasonal experiments were moved from water to land and land to water every week to mimic the movement between these interfaces in tidal seas for a period of six weeks. Constant exposure to the shallow water lasted for between 140 and 210 days. With every sampling, the biofilm was scratched off the decaying leaves of seagrass. The development of its microbial community as well as biomass loss were investigated. C/N-ratio was measured with the respective changes over time. The influence of abiotic parameters like light, salinity and temperature for the microbial community during the decay were then evaluated. 
In respect to decomposition processes at micro-tidal coasts, these studies provide an important insight into seagrass decay, at land and in the shallow water. Beach management processes at recreational beaches, and the possibilities of nutrient back-flow, need to be implemented into nature-compatible approaches. A corresponding system based on this research results can be promoted for leading to a balanced coexistence between man and nature.  

How to cite: Schätzle, P.-K., Schubert, H., Kesy, K., Bengtsson, M., Koziorowska-Makuch, K., and Kuliński, K.: The decay of Zostera marina, representative for beach wrack, at the micro-tidal southwestern Baltic Sea coast on the island of Poel in Germany, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5467, https://doi.org/10.5194/egusphere-egu23-5467, 2023.

The present study aimed to evaluate the implementation of the biomarkers: Lipid Peroxidation (LPO) and Lactate Dehydrogenase (LDH) assays as an early warning tool for monitoring seagrass health status in relation to global and local environmental change in the Gulf of Aqaba, Jordan. To reach our objectives, we have developed a novel Seagrass Rack Semi-Automated Stress System (SR-SASS) to achieve comparable, short-term heat stress assays. The system consisted of twelve 15-L flow-through tanks that allowed the running of six independent temperature experiments simultaneously. The selected thermal stress assays: LPO and LDH, were adopted to collect an entire observation regarding the biological response of seagrass to thermal stress. The seagrass samples (Halophila stipulacea) were collected from quadrats measuring 0.25 m² placed 50 m apart along three transects at the Marine Science Station (MSS, a protected area with no anthropogenic impact) from a depth of approximately 15 m. The samples were immediately transferred to the aquaculture unit at the MSS and incubated in a monitored aquarium filled with artificial seawater with a salinity of 40.0 ± 0.5 psu and pH value of 8.0 ± 0.1. Furthermore, seagrass samples were randomly distributed over the SR-SASS, including two replicate tanks per temperature treatment. Consequently, all samples were kept at 25 °C overnight; and, the control tanks remained at 25 °C, and the treatment tanks were subjected to heat stress as (T1) Mild: (temp. 27 °C), (T2) Moderate (temp. 33 °C), and (T3) Extreme (temp. 35 °C) for one hour. Temperature profiles were successfully controlled across experiments. Our results showed that the control group exhibited normal LPO levels (0.124 μM/g). There was a significant increase in the LPO level in seagrass leaf homogenate from the treated groups by 4-fold in the case of T2 and 6-fold in the case of T3 compared with those of the control group (P<0.05). However, no significant increase was observed in T1 (P>0.05). Similar findings were noted regarding the LDH activity levels. A further increase was shown as 73.12 and 83.34 U/mL in the case of T2 and T3, respectively, compared to control (19.84 U/ml) as reflected in the elevation of malondialdehyde values which appear temperature-dependent. Moreover, our results demonstrate that the seagrass (H. stipulacea) shows above-average physiological thermal tolerance in different experimental exposures. H. stipulacea exhibits resilience to 7 °C above the maximum summer means temperatures. Our findings provide novel information on the effects of elevated temperature on the resilience of seagrass exposed to short-term heat stress challenges. 

Keywords: Halophila stipulacea; Global warming; Gulf of Aqaba

How to cite: Wahsha, M. and Al-Najjar, T.: Preliminary observations on the Halophila stipulacea resilience to thermal stress at the northern tip of the Red Sea, Jordan, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9825, https://doi.org/10.5194/egusphere-egu23-9825, 2023.

Deep-sea floors act as reservoir for various marine mineral deposits rich in strategic metal resources important to growth of nation’s economy, national security and the emerging blue economy. Central Indian Ocean Basin (CIOB) is a region with vast marine mineral deposits with a congregation of metals in the form of nodules known as polymetallic nodules (PMN). Government of India signed a 15-year contract with International Seabed Authority (ISA) for exploration of PMN from CIOB. Extensive survey and other scientific developmental activities have been carried out in 75,000km² area retained by India in CIOB. To conduct mining activities prior to assessment of impact on environment would remark an unwise undertaking. Deep sea mining operation will inevitably impact the surrounding ecosystem due to removal and separation of nodules from soft sediments and increases in suspended finer particles from the altered deep-sea sediment. Disturbances to sediments will have impact on the speciation (labile/inert complexes) of sedimentary metal complexes and may increase metal mobility and bioavailability in marine ecosystem. Study on the possible impact of deep-sea PMN mining requires systematic scientific investigation.This study presents kinetic speciation of metal in surface sediments and their downcore profile.To understand the stability and lability of metals, kinetic speciation study is carried out using ethylenediaminetetraacetic acid (EDTA) as the extracting reagent. Kinetic fractionation studies were performed from two sediments core collected from Test mining site (TMS) and Reference mining site (RMS) in CIOB to determine the metal-sediment complexes and their fate, mobility and bioavailability. Concentration of labile metals complexes and their dissociation rate constant in deep sea sediment can be an index for their bioavailability. It was found that total concentration of Cu and Co gradually decreases, whereas Ni increases in the study area The observed results suggest that the stability of metals-sediment complexes for Cu, Ni, and Co with respect to the depth of the sediment cores gradually increased in the study area. This study suggests that disturbances of deep-sea sediments during PMN mining may not increase labile metals complexes at water-sediment interfaces in the surrounding marine ecosystem. However, results obtained from two sediment cores from Test mine site and Reference mine site respectively may not satisfy representation of the entire 75,000km² CIOB. Further study is recommended to provide better understanding of the impact of mining activities on marine ecosystem.

How to cite: Sitlhou, L. and Chakraborty, P.: Sediment Disturbance during PMN Mining and Its Impact on Metal Speciation of Sedimentary Cu, Ni, Co in Central Indian Ocean Basin, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-846, https://doi.org/10.5194/egusphere-egu23-846, 2023.

Bottom trawling has a direct impact on biogeochemical cycling and benthic-pelagic coupling. Despite extensive trawling activities in many shelf seas, the effects on benthic-pelagic exchanges is often not considered in marine ecosystem simulations. In this study, in order to gauge the effects of bottom trawling on North Sea ecosystem productivity, two model simulations were carried out for the period 2000-2005 using the 3D, fully coupled ecosystem model SCHISM-ECOSMO, which allows for coupled simulation of the benthic and pelagic ecosystem. The first simulation includes only natural resuspension while the second experiment also considers a parametrization for bottom trawling induced resuspension. Daily forcing for bottom trawling resuspension rates was generated based on available data of fishing activity including the position, size and engine power of individual vessels, in combination with estimated resuspension rates of various fishing gears in different types of sediment. The results of these simulations were then analyzed with regard to the importance of bottom trawling for the pelagic primary production of the North Sea ecosystem. In addition, we analyzed trawling-induced changes in bottom water oxygen and sedimentary carbon, phosphorus and nitrogen pools.

How to cite: Tiwari, P., Porz, L., Daewel, U., and Schrum, C.: Bottom trawling impacts on benthic-pelagic coupling in the North Sea, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11712, https://doi.org/10.5194/egusphere-egu23-11712, 2023.

River plumes have a significant impact on phytoplankton primary production by carrying high nutrient loads, suspended particles and dissolved organic matter into the seawater.
Dynamic processes mainly modulate nutrient availability as well as light attenuation along the water column thus influencing marine phytoplankton distribution along the plume gradient, also according to the seasonal variability of the river flow.
A series of oceanographic cruises have been conducted since 2020 to examine how physical processes influence phytoplankton dynamics within the entire physiographic unit, which extends between Capo d'Anzio and Capo Linaro. A high phytoplankton abundance was observed both at the surface and bottom depths up to a bathymetry of 40-60 meters. At the surface, it was directly related to the Tiber River plume, while at the bottom it seemed to be linked to sediment resuspension phenomena. Going offshore, the distribution of phytoplankton along the water column assumed the Typical Tropical Structure (TTS) trend with a well-formed Deep Chlorophyll Maximum (DCM) around 60 to 90 meters depth.
In light of these findings, to deepen our understanding of these phenomena, a detailed campaign along the river mouth was carried out in May 2022 in collaboration with the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS to collect hydrological (temperature, conductivity - salinity, density-, dissolved oxygen) and biogeochemical (PAR, downwelling and upwelling irradiance, nutrients, phytoplankton photosynthetic efficiency, composition and biomass, TSM, CDOM) data. 

How to cite: Madonia, A., Amore, E., Cerino, F., Cibic, T., Coppini, G., Fersini, G., Fornasaro, D., Kralj, M., Piermattei, V., and Marcelli, M.: Influence of Tiber River plume on phytoplankton primary production, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14050, https://doi.org/10.5194/egusphere-egu23-14050, 2023.

Marine environmental observation is a broad topic that becomes crucial when considering critical environments, like the Arctic region which is particularly vulnerable to contamination due to the amplified effects of climate change in this area. The melting of tidewater glaciers, which has intensified in the last years, can generate a delivery of freshwater and suspended sediment into the fjord water. These phenomena can release contaminants that have accumulated in the ice over the past century, affecting fjords’ ecosystems. Despite the importance of these processes, there is no regular monitoring in place to precisely locate and sample freshwater outflows from glaciers and to track the environmental changes they trigger. The lack of data is, very often, a penalizing factor on the one hand to understand the processes and the phenomena that are occurring and on the other to implement possible mitigation actions for the conservation of the ecosystems. The use of autonomous robotic systems as fundamental data-gathering tools allows new perspectives and a greater understanding of glacier-melting related processes thanks to the possibility of collecting data not otherwise obtainable, with unique spatio-temporal resolutions.

This contribution describes the technological enhancements to enable the use of a highly reconfigurable surface robotic platform (SWAMP ASV) as part of a data acquisition campaign that took place in July/August 2022 in cooperation with Institute of Oceanology, Polish Academy of Sciences (IO PAN), in semi-enclosed glacial bays that characterize the Hornsund fjord. Sampling were performed at three glacier fronts (Storbreen, Hornbreen and Hansbreen) with the purpose of identifying the position of the freshwater outflows, sending the robotic platform to the place where the plumes were present (otherwise not possible given the proximity to the glacier front and the significant calving activity in progress), collecting water samples for the subsequent analyses and evaluating the presence of heavy metals of anthropogenic origin, and simultaneously recording the chemical-physical and bathymetric parameters for a 3D characterization of the water masses and the environment. Preliminary results obtained from the acquired data will be discussed, together with the data management procedure implemented in a perspective of contributing to the global observation effort, also promoted by the United Nations.

Acknowledgments: the authors thank Prof. Agata Zaborska (IO PAN) and the Reload project for organizing the acquisition campaign and for the logistical support in Svalbard. The authors wish to thank Mauro Giacopelli and Edoardo Spirandelli (CNR-INM) for their fundamental contribution to SWAMP design and development.

How to cite: Ferretti, R., Aracri, S., Bibuli, M., Bruzzone, G., Bruzzone, G., Caccia, M., Motta, C., and Odetti, A.: Application of a highly reconfigurable surface robotic platform for freshwater plume characterization and sampling near tidewater glacier front in Arctic critical environment., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5514, https://doi.org/10.5194/egusphere-egu23-5514, 2023.

Among the objectives of marine ecology recently emerges the one concerning the maintenance and recovery of the ecological functions of ecosystems. This is particularly evident in the coastal marine environment, which is rich in habitats and species that provide many essential ecosystem services, like seagrasses. Seagrasses are important and productive coastal systems that provide nursery areas, carbon sequestration, protection from erosion, bioremediation, and oxygen production.

Seagrasses are subject to both indirect and direct impacts. Among the indirect impacts, the one linked to the perturbations of the sedimentary dynamics of the coastal marine environment, caused by various factors, such as changes in land use, regulation of water basins, and climate change, is particularly significant. Among the direct impacts, the one caused by anchorages or in general by all activities involving the destruction of substrates is significant (e.g., illegal fishing, development of coastal infrastructure, construction, or expansion of existing ports).

In this perspective, the use of innovative methodologies and technologies able to facilitate the monitoring activities of the coastal marine environment is particularly helpful. New cost-effective devices and autonomous survey technologies contribute to the optimization of the cost-benefit ratio in field survey activities, to the limitation of the impacts of the survey activities themselves on the habitats, and to favor the acquisition of more real-time data.

How to cite: Scanu, S., Bonamano, S., Madonia, A., Piermattei, V., Resnati, A., Scagnoli, E., Varini, F., and Piazzolla, D.: Application of autonomous surveys technologies for the evaluation of habitat restoration interventions sites on coastal areas, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12487, https://doi.org/10.5194/egusphere-egu23-12487, 2023.

Climate change is deeply affecting oceanographic, biogeochemical, and hydrological processes and consequently influencing the ecological patterns of ecosystems. Indeed, marine habitats and species are facing many alterations in their structure, functioning, and in their capacity of providing ecosystem services. To investigate and explore the distribution and potential variation of habitats and species under future climate change scenarios, Habitat Suitability Models (HSMs) have been widely applied during the last years for their recognized ability in predicting the suitability of a location for species and habitats in correlation with the environmental conditions.

With the application of two of the best-known HSMs (Random Forest and MaxEnt), this research intends to investigate the distribution of the coralligenous, a widespread habitat in the Northern Adriatic Sea threatened by the effects of climate change, and identify its potential variation in a severe future scenario. The analysis consisted in examining the correlation between the habitat distribution with environmental parameters obtained from online databases and a set of dedicated ocean model simulations applied in recent past conditions and under RCP 8.5 climate change scenario. Furthermore, to explore the potential uncertainty of the environmental variables in future conditions, a sensitivity analysis has been implemented by running additional HSMs simulations set up with variables' increments and decrements resulting from projections modeled by other research.

The models perform very well in predicting habitat distributions. The prediction under the climate change scenario shows that opportunistic species (e.g. turf-dominant algae) find more suitable conditions in the area being more tolerant to stressful conditions and alterations of the environmental variables. As a result, calcareous macroalgae appear to be more vulnerable to climate change effects, including increases in temperature, nutrient concentrations, salinity, and velocity. Overall, the results of the sensitivity analysis confirmed the results predicted by models; however, Random Forest also shows a higher sensitivity to uncertainty than MaxEnt.

In conclusion, this study gives a sight of the likely ecological behavior in correlation with past environmental conditions and future alterations due to climate change. Besides, HSMs confirm to be very useful tools to develop adequate conservation strategies and/or identify priority areas to protect. Thanks to the sensitivity analysis, additional hints about the models’ behavior according to the environmental uncertainties are extrapolated, allowing to consider with consciousness the results and understanding of the potentialities of the models according to the data in possession.

How to cite: Vitelletti, M. L., Manea, E., Bongiorni, L., Ricchi, A., Sangelantoni, L., and Bonaldo, D.: Habitat suitability modelling of coralligenous in the Northern Adriatic Sea and potential distribution under climate change scenario, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17244, https://doi.org/10.5194/egusphere-egu23-17244, 2023.

Within the European Interreg Italy-Croatia project “CoAStal and marine waters integrated monitoring systems for ecosystems proteCtion AnD managemEnt (CASCADE)” ( https://www.italy-croatia.eu/web/cascade), an off-line coupled physical-biogeochemical box-model was implemented in the shallow Goro lagoon (northern Adriatic Sea, Po river delta region) in order to study its biogeochemical dynamics. The lagoon is subject to intensive shellfish (Ruditapes Philippinarum) farming: more than one third of the lagoon surface is exploited for clam farming, with an annual production that reached a maximum of approximately 15,000 t y^-1 in the early 1990s.
The biogeochemical component of the modelling system is the Biogeochemical Flux Model (BFM), accounting for the biogeochemical cycling processes occurring in water and sediments, including (with a functional groups approach) the planktonic and the zoobenthic biota, and fully resolving the benthic pelagic coupling. BFM is implemented in several areas of the lagoon having homogeneous characteristics and different shellfish farming conditions. The areas resolved by the BFM are connected among each other by the mass exchanges (dissolved and particulate) depending by the water circulation in the lagoon that is modeled by the Shallow Water Hydrodynamic Finite Element Model (SHYFEM).
The results of the simulation show that the model is able to capture the essential dynamics of the lagoon, with values almost in the same order of magnitude with the measurements from experimental campaigns runned during the project. Particular attention (trough sensitivity experiments) is given to the impact of the the shellfish farming on the lagoon biogeochemical dynamics. The ultimate goal of this work is to provide stakeholders with useful information regarding the evolving biogeochemical conditions that favor the sustainability  of the  shellfish farming.

How to cite: Arcamone, R., Zavatarelli, M., Biolchi, L., Unguendoli, S., and Valentini, A.: Modeling the biogeochemical dynamics of a shallow lagoon impacted by intensive shellfish farming (Sacca di Goro, Po river delta, Northern Adriatic Sea)., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5119, https://doi.org/10.5194/egusphere-egu23-5119, 2023.

Marine ecosystem restoration actions are becoming increasingly more popular in many areas of the world, representing one of the greatest challenges to date that can deliver results in line with the UN 2030 Agenda for Sustainable Development. However, their success rate is highly variable and depends mainly on the specific biological and ecological characteristics of the species involved, their ecosystem functioning, and undoubtedly on how, where and when restoration is conducted. 

Knowledge about the factors that enhance or limit the success of restoration efforts, with respect to a given habitat is, to date, very limited for the marine environment. Different sensitivity to human pressures and the spatial variability in the ecological variables that determine their presence and distribution are undoubtedly key factors, and it is therefore necessary to provide detailed and focused information on the selection of restoration sites and methods, from which successful and sustainable restoration actions depend. 

The national RENOVATE project (ecosystemic appRoach to the EvaluatioN and testing of cOmpensation and mitigation actions in the marine enVironment: the cAse of the civiTavEcchia harbuor), coordinated by CMCC (Mediterranean Centre for the study of Climate Changes) and funded by “AdSP (Autorità di SIstema Portuale) of the north-central Tyrrhenian Sea” is performing an integrated methodology for the compensation of Mediterranean marine ecosystems, damaged by anthropogenic impacts, in selected areas located offshore Civitavecchia harbor, where port expansion activities will soon be started. In this context, the present work focuses on providing a high resolution mapping of Posidonia oceanica meadows within the targeted project areas and introduces a new approach, based on the application of geospatial modeling techniques, to perform a semi-automatic detection of appropriate restoration sites. The proposed work flow is based on performing quantitative analysis of acoustic remote sensing data (i.e. Multibeam bathymetry and side-scan sonar backscatter intensity) applying Object-Based Image Analysis (OBIA) techniques, and ad-hoc developed numeric modeling. Our major goal was to classify seafloor suitability for restoration actions, according to variation in landscape spatial arrangement of P. oceanica meadows (determined by type of lower and upper limit, type of seagrass bed morphology, meadow patchiness, etc), quantified through the morphometric characterization of their geospatial configuration and architecture, and the operational depth for planned seagrass implantation strategy. Our work attempts to contribute to the development of efficient methodologies for the detection of suitable restoration sites that can support long-term growth and survival of P. oceanica meadows.

How to cite: Savini, A., Varzi, A. G., Marino, L., Fersini, G., Piazzolla, D., Scanu, S., and Marcelli, M.: Geospatial modeling for evaluating restoration suitability of Posidonia oceanica meadows offshore Civitavecchia (eastern Tyrrhenian margin, Mediterranean Sea), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14936, https://doi.org/10.5194/egusphere-egu23-14936, 2023.

The progress and future commercial success of each wave energy device is linked to the fact that the technology, the local wave motion characteristic and environmental condition are suitable to exploit the available wave energy resources in a specific coastal area. In the last years, several wave energy converters have reached an advanced development stage, such as the WaveSAX-2, an oscillating water column device suitable for been installed in existing coastal structures. Considering that the device can be installed directly on the breakwater wall or even inside the caissons, the impact on the marine environment can be considerably reduced. The device at scale 1:5 has been already tested in the Civitavecchia port (north eastern Tyrrhenian sea, Italy) in 2018 and 2020 leading to the evaluation of the power matrix (i.e. the expected power production for each local wave condition).

Thanks to the information obtained by the sea tests of the device, the wave energy potential exploited by WaveSAX-2 was evaluated, both in the offshore zone and in proximity of the Civitavecchia harbor structures, using the Mediterranean wave reanalysis product distributed as part of Copernicus Marine Service catalogue.

In the area around the Civitavecchia port, the main characteristics (height, period, direction) of the wave motion and the potential energy production of the device have been computed using the SWAN model that allows to obtain a high spatial resolution in the coastal zone. The model was successfully validated with wave data collected in 2017 and 2018 using an ADP instrumentation mounted within the Barnacle structure at 20 m depth in the northern area of Civitavecchia port.

The model results show that the highest energy levels are located in the northern and central part of Civitavecchia port where the breakwater structure has highly reflective features. These values resulted even greater than the energy found offshore. The southern part of the breakwater, which is protected by tetrapods with low reflective capacities, is instead characterized by lower values of wave energy. The study also highlights the improvement in the generation of the WaveSAX-2 due to the capacity of the new turbine to have a better efficiency in the exploitation of the lowest waves which are the most frequent ones in the study area.

The work demonstrates that high spatial resolution numerical modeling is a fundamental tool to analyze and accurately predict the wave energy potential exploitable by wave energy converters (WEC) in coastal areas affected by the presence of port structures. It also represents  a powerful tool for the optimization of the device array design, leading to maximize the energy production and minimize the environmental impact in the area.

How to cite: Bonamano, S., Peviani, M. A., Burgio, C. G., Fersini, G., and Marcelli, M.: High resolution numerical modeling supporting the evaluation of the WaveSAX-2 power generation in the coastal area around the Civitavecchia port, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7655, https://doi.org/10.5194/egusphere-egu23-7655, 2023.

Global climate change and extensive human activity put compounding pressure on coastal marine ecosystems, resulting in habitat degradation, a reduction in ecosystem services, and an increase in marine ecosystem disasters. Therefore, simulating the response of ecosystem health conditions to climate change and different human activity scenarios can provide direct and effective information to improve ecologically sound management strategies for the sustainable use and development of coastal areas. In the present work, we set up a scenario simulation model using machine learning methods. Individual and integrated scenarios of Climate change and human activity impact were designed to predict the possible responses of marine ecosystem health conditions.

How to cite: Hu, Z., Sun, X., and Sun, S.: Scenario simulations of marine ecosystem health on China’s coast, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4998, https://doi.org/10.5194/egusphere-egu23-4998, 2023.

We investigated an unexpected microplastic (MP) leakage event that occurred along the coastline of Yantai in January 2021. Sediment samples were collected from three zones on 9 beaches. MPs were identified with an average abundance of 247.6±125.6 items/m² on 7 beaches. The total amount of MPs from the leak accident was estimated to be 1.50×10⁷ items (514.67 kg). The MPs were identified as polyethylene (PE), polypropylene (PP), and PP/PE blends using μ-FT-IR analysis. By utilizing a numerical model, the transmission process and potential source of MPs were demonstrated. The modeling results showed that the MPs might originate from the central and western part of the Bohai Sea and be driven to the beaches of Yantai by northwest wind and wind-induced surface current. However, due to the absence of direct evidence, the simulation results might only indicate the range of the leaking source, which was the movement trajectory of MPs.

How to cite: Zhang, C.: Model studies on transport of microplastics from a leak accident, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4766, https://doi.org/10.5194/egusphere-egu23-4766, 2023.

Coastal oceans offer multifaceted ecosystem level services and represent a key part to achieve UN SDG Goals including SDG14. The northeast coastal Bay of Bengal (BoB) in South Asia is interspersed with several coastal biotopes influenced by the Ganga-Brahmaputra-Meghna delta among others and contribute immensely to sustainable blue economy. The Sundarbans mangrove, world’s largest continuous mangrove, a UNESCO World Heritage Site and a RAMSAR site along with long intertidal zones represent characteristic features of this region. These sites are increasingly reeling from numerous anthropogenic stressors and the scales of anthropogenic disturbances were characterized through benthic foraminifera coenosis over three seasons along with robust measurement of organic carbon in sediment as well as integrating new technologies such as eDNA approach. The studied sites showed overwhelming abundance of calcareous taxa Ammonia spp. and Quinqueloculina spp. as well as low taxon level diversity. There was notable high abundance of dead and degraded tests indicating potential taphonomic alterations that indicated changes influenced by lowering of porewater oxygen content, N:P stoichiometry and possible changes in freshwater flow. The values of total organic carbon of sediment exhibited wide variability and the strong influence of anthropogenic forcings in closer proximity to human influences. There was resulting evidence of anaerobic degradation of sediment organic matter resulting in changes in sediment pH and taphonomic alteration of benthic foraminifera tests. The eDNA based high-throughput sequencing exhibited signs of low diversity of benthic foraminifera and signals influenced by anthropogenic stressors such as forms of nitrogen. The study based on spatio-temporal mosaics of mapping of coastal health of northeast coastal BoB indicates increasing human pressure will have long-term effects on SDG Goal 14 and beyond.

How to cite: Mandal, A. and Bhadury, P.: Tracking ecological health status of a tropical coastal ocean- applicability of benthic foraminifera coenosis, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-134, https://doi.org/10.5194/egusphere-egu23-134, 2023.