Efficient AIS Data Processing for Environmentally Safe Shipping

Reducing ship accidents at sea is important to all economic, environmental, and cultural sectors of Greece. Despite an increase in traffic and national monitoring, ships formulate routes according to their best judgment risking an accident. In this study we take a dataset spanning in 3 years from the AIS (Automatic Identification System) network, which is transmitting in public a ship's identity and location with an interval of seconds, and we load it in a trajectory database supported by the Hermes Moving Objects Database (MOD) system. Presented analysis begins by extracting statistics for the dataset, both general (number of ships and position reports) as well as safety related ones. Simple queries on the dataset illustrate the capabilities of Hermes and allow to gain insight on how the ships move in the Greek Seas. Analysis of movement based on an Origin-Destination matrix between interesting areas in the Greek territory is presented. One of the newest challenges that emerged during this process is that the amount of the positioning data is becoming more and more massive. As a conclusion, a preliminary review of possible solutions to this challenge along with others such as dealing with the noise in AIS data is mentioned and we also briefly discuss the need for interdisciplinary cooperation.This research was partially supported by AMINESS project funded by the Greek government (www.aminess.eu). Cyril Ray was supported by a Short Term Scientific Mission performed at the University of Piraeus by the COST Action IC0903 on “Knowledge Discovery from Moving Objects” (http://www.move-cost.info). IMIS Hellas (www.imishel las.gr) kindly provided the AIS dataset for research purposes

Efficient AIS Data Processing for Environmentally Safe Shipping

Reducing ship accidents at sea is important to all economic, environmental, and cultural sectors of Greece. Despite an increase in traffic and national monitoring, ships formulate routes according to their best judgment risking an accident. In this study we take a dataset spanning in 3 years from the AIS (Automatic Identification System) network, which is transmitting in public a ship's identity and location with an interval of seconds, and we load it in a trajectory database supported by the Hermes Moving Objects Database (MOD) system. Presented analysis begins by extracting statistics for the dataset, both general (number of ships and position reports) as well as safety related ones. Simple queries on the dataset illustrate the capabilities of Hermes and allow to gain insight on how the ships move in the Greek Seas. Analysis of movement based on an Origin-Destination matrix between interesting areas in the Greek territory is presented. One of the newest challenges that emerged during this process is that the amount of the positioning data is becoming more and more massive. As a conclusion, a preliminary review of possible solutions to this challenge along with others such as dealing with the noise in AIS data is mentioned and we also briefly discuss the need for interdisciplinary cooperation.This research was partially supported by AMINESS project funded by the Greek government (www.aminess.eu). Cyril Ray was supported by a Short Term Scientific Mission performed at the University of Piraeus by the COST Action IC0903 on “Knowledge Discovery from Moving Objects” (http://www.move-cost.info). IMIS Hellas (www.imishel las.gr) kindly provided the AIS dataset for research purposes

The use of storm fragments and biodegradable replanting methods allows for a low-impact habitat restoration method of seagrass meadows, in the eastern Aegean Sea

Seagrasses are important marine ecosystems but are vulnerable to physical damage from anthropogenic activities such as anchoring and trawling. Replanting damaged areas can represent a viable restoration strategy, yet current methods rely on the removal of plants from existing meadows and in some cases the use of non-sustainable planting materials. In this paper, we present evidence of a sustainable replanting strategy. Storm fragments of the endemic Mediterranean seagrass, neptune grass Posidonia oceanica were collected from the shore and shallow water, both the plagiotropic and orthotropic (horizontal and vertical) growth forms were then replanted using one of two biodegradable materials, coconut fibre pots or bamboo stakes, to secure them to the seafloor. Establishment of plagiotropic fragments were increased by bamboo anchorage (x̅ = 89% SE ± 0%) compared to orthotropic storm fragments (x̅ = 66.5% SE ± 6.5%). By contrast a coconut fibre method resulted in greater establishment of orthotropic fragments (x̅ = 79% SE ± 7%) compared to plagiotropic (x̅ = 51% SE ± 11%). Fragments showed some blade growth, but little shoot growth after 15 months. The fragment shoot and blade growth did not differ between the plagiotropic or orthotropic fragments replanted by bamboo stakes or coconut fibre pot. Our results suggest that the use of storm fragments and biodegradable anchoring materials constitutes a viable, non-destructive replanting technique in seagrass restoration. Furthermore success can be increased by selecting a growth-form appropriate planting method

Scientific, societal and pedagogical approaches to tackle the impact of climate change on marine pollution

Marine pollution impacts coastal nations around the world, and more so: (a) in confined maritime areas with significant marine traffic, (b) where exploitation of natural and mineral resources is taking place, or (c) in regions witnessing pressure from tourism, local population growth, and industry. In this work, Digital Elevation Models, hydrographic, and climatic data are used together with computer simulations to understand the control of climate change on marine pollution. The results show that different climate change signals can potentially alter the flow and concentration of pollution in the European Seas, when compared to the present day. Ultimately, this work identifies the main sources of marine pollution as: (1) rivers and streams near cities and industrialised areas, (2) coastal areas experiencing sudden demographic pressures, (3) offshore shipping lanes in which oil and other marine debris are released, and (4) areas of rugged seafloor where industrial fishing takes place. This paper finishes by describing new educational material prepared to teach school children around the world. It explains why how a new training curriculum and e-game developed by Sea4All can be crucial in future Environmental Education and Education for a Sustainable Development

Microplastic shape influences fate in vegetated wetlands

Coastal areas are prone to plastic accumulation due to their proximity to land based sources. Coastal vegetated habitats (e.g., seagrasses, saltmarshes, mangroves) provide a myriad of ecosystem functions, such as erosion protection, habitat refuge, and carbon storage. The biological and physical factors that underlie these functions may provide an additional benefit: trapping of marine microplastics. While microplastics occurrence in coastal vegetated sediments is well documented, there is conflicting evidence on whether the presence of vegetation enhances microplastics trapping relative to bare sites and the factors that influence microplastic trapping remain understudied. We investigated how vegetation structure and microplastic type influences trapping in a simulated coastal wetland. Through a flume experiment, we measured the efficiency of microplastic trapping in the presence of branched and grassy vegetation and tested an array of microplastics that differ in shape, size, and polymer. We observed that the presence of vegetation did not affect the number of microplastics trapped but did affect location of deposition. Microplastic shape, rather than polymer, was the dominant factor in determining whether microplastics were retained in the sediment or adhered to the vegetation canopy. Across the canopy, microfibre concentrations decreased from the leading edge to the interior which suggests that even on a small-scale, vegetation has a filtering effect. The outcome of this study enriches our understanding of coastal vegetation as a microplastics sink and that differences among microplastics informs where they are most likely to accumulate within a biogenic canopy

Is All Seagrass Habitat Equal? Seasonal, Spatial, and Interspecific Variation in Productivity Dynamics Within Mediterranean Seagrass Habitat

Seagrass meadows’ ability to capture carbon through sequestering autochthonous carbon via photosynthesis means they could represent a potential nature-based solution to rising carbon emissions. In multispecies seagrass communities, and due to species introduction or predicted range shifts, it is important to know which species deliver different carbon sequestration gains to inform conservation actions. Large benthic chamber experiments (volume = 262L) assessed the seasonal and spatial variation in metabolism dynamics of the endemic and dominant Mediterranean seagrass, P. oceanica whilst small benthic chamber experiments (volume = 7L) compared the dynamics between, P. oceanica the native C. nodosa and non-native H. stipulacea. Within shallow P. oceanica edge habitat lower Net Apparent Productivity (NAP) occurs in autumn ((Formula presented.) = 1.3, SD ± 2.95 O2 mmol m-2 d-1) compared to summer ((Formula presented.) = 9.9, SD ± 2.75 O2 mmol m-2 d-1 corresponding with periods of light limiting and light saturating conditions, but it remains overall autotrophic annually (2.3 C mol m-2 yr-1). However, spatial heterogeneity exists, the center areas of P. oceanica were more productive (NAP (Formula presented.) =19.7, SD± 3.83 O2 mmol m-2 d-1) compared to edge habitat with spatial changes in productivity relating to plant surface area (96%), shoot density (81%), blade length (72%) and seagrass percentage cover (64%). Under comparative conditions in a sparse multispecies area of the meadow the species demonstrated different capacities for carbon fixation. H. stipulacea was carbon positive and P. oceanica fluctuated between positive and negative carbon balance suggesting both can maintain a balance between carbon fixation and carbon utilised for metabolic activity. In contrast the C. nodosa here would be expected to deteriorate as it was utilising carbon more than it was fixing (NAPN2 ((Formula presented.) = -0.0012, SD ± 0.0007 O2 mmol cm-2 d-1). This study demonstrates that not all seagrass habitat is equal. If seagrass meadows are to play a part in mitigating CO2 emissions, variability in primary productivity within seagrass meadows needs to be accounted for to produce accurate total fixed carbon estimates, and subsequently autochthonous carbon sequestration estimates. This means seagrass meadow species composition and the condition of these meadows must be better understood

Bacterial Community Legacy Effects Following the Agia Zoni II Oil-Spill, Greece

In September 2017 the Agia Zoni II sank in the Saronic Gulf, Greece, releasing approximately 500 tonnes of heavy fuel oil, contaminating the Salamina and Athens coastlines. Effects of the spill, and remediation efforts, on sediment microbial communities were quantified over the following 7 months. Five days post-spill, the concentration of measured hydrocarbons within surface sediments of contaminated beaches was 1,093–3,773 μg g–1 dry sediment (91% alkanes and 9% polycyclic aromatic hydrocarbons), but measured hydrocarbons decreased rapidly after extensive clean-up operations. Bacterial genera known to contain oil-degrading species increased in abundance, including Alcanivorax, Cycloclasticus, Oleibacter, Oleiphilus, and Thalassolituus, and the species Marinobacter hydrocarbonoclasticus from approximately 0.02 to >32% (collectively) of the total bacterial community. Abundance of genera with known hydrocarbon-degraders then decreased 1 month after clean-up. However, a legacy effect was observed within the bacterial community, whereby Alcanivorax and Cycloclasticus persisted for several months after the oil spill in formerly contaminated sites. This study is the first to evaluate the effect of the Agia Zoni II oil-spill on microbial communities in an oligotrophic sea, where in situ oil-spill studies are rare. The results aid the advancement of post-spill monitoring models, which can predict the capability of environments to naturally attenuate oil

Environmental variables influencing occurrence and distribution of Delphinus delphis in the eastern Aegean Sea (eastern Mediterranean Sea)

Cetaceans are considered bioindicators of the health state of marine ecosystems owing to their wide distribution across the different aquatic ecosystems in the world and their significant top-down control role in the food chain, despite their low biomass. At the same time, effective management of wild cetacean populations severely affected by human pressure requires extensive knowledge on species distribution, habitat use, and associated threats. In this context, defining the factors that directly influence the local occurrence and distribution of cetaceans is one of the underlying challenges and is essential for their conservation and long-term survival. Delphinus delphis sightings data, collected between 2017 and 2021 during 284 standardized vessel-based surveys, were used to set up a presence–absence distribution model in the eastern Aegean Sea, eastern Mediterranean Sea. Binomial generalized additive models with logit as link function were run using the R package mgcv (restricted maximum likelihood method) and different biogeochemical explanatory variables collected from different sources. Longitude, latitude, salinity, chlorophyll a, dissolved ammonium, and dissolved phosphate were selected as non-collinear predictive variables. Through a model validation based on a 10-fold cross-validation approach and a random data splitting procedure of 70%/30% (train/test dataset), a model formula has been selected with an explained deviance of 38.10%, an Akaike information criterion value of 1,661.3, and an area under curve of 0.91. The study confirms that long-term time series of satellite-derived data are useful to assess the occurrence and the spatial distribution of D. delphis, suggesting the need for a better understanding of the influence of these environmental factors especially in the framework of climate changes. Outcomes highlight the need to test further variables and further methods in order to provide increasingly reliable results in view of the conservation measures that must be adopted to stop or reduce the degree of pressure to which these species are subjected

Combining monitoring approaches as a tool to assess the occurrence of the Mediterranean Monk Seal in Samos Island, Greece

With a current global estimation of 600–700 individuals, Monachus monachus is considered among the most threatened seal species globally and is ranked as “Endangered” by the IUCN Red List of Threatened Species. The Mediterranean distribution of the species is fragmented, and the largest known sub-population inhabits its easternmost areas. The present study analyses the occurrence of M. monachus on Samos Island, in the north-eastern Aegean Sea, Greece. From May 2017 to November 2019, data were collected through a combination of monitoring approaches, including visual monitoring from a land position, opportunistic sightings collected by citizen science, and data of stranded individuals. Results indicate the constant occurrence of monk seals in the waters and coastal areas of Samos Island, confirming the importance of this area for conservation purposes. Furthermore, the results show that an integrated methodological approach can contribute to enhancing and increasing data collection, representing an effective method for conservation studies. This approach could be applied in other locations, allowing the scientific community to identify regions of interest, where to expand targeted monitoring and apply conservation measures

Pinna nobilis in the Greek seas (NE Mediterranean): on the brink of extinction?

The Mediterranean endemic fan mussel Pinna nobilis is suffering an ongoing basin-scale mass mortality event (MME) since 2016. As most Mediterranean populations have collapsed, the species has been declared as Critically Endangered in the IUCN Red List of threatened species. In an effort to track the progress of the MME and provide updated information on the status of the species in the Greek seas, data collected through dedicated surveys and opportunistic assessments during 2019 and 2020 have been compiled. During surveys conducted at 258 sites, a total of 14,589 fan mussels were recorded, of which 81.1% were dead. Of the remaining 2,762 live individuals, 256 were juveniles. Two marine areas that still sustain living populations were identified, namely Kalloni Gulf (Lesvos Island), and Laganas Bay (Zakynthos Island). The inner part of Kalloni Gulf appears to maintain the largest surviving population of the species in the eastern Mediterranean, with an abundance estimate of 684,000 individuals (95% confidence interval: 322,000-1,453,000). Solitary, potentially resistant, scattered individuals were recorded at several sites. Other previously abundant populations that had been assessed in the past, specifically those of Lake Vouliagmeni (Korinthiakos Gulf), Souda Bay (Crete) and Gera Gulf (Lesvos Island) with a total of ~350,000 individuals, have now been wiped out. Our results document the collapse of most P. nobilis populations throughout the Greek seas. The MME has progressed substantially between early 2019 and mid-2020, as indicated by the increase in mortality at sites consecutively monitored multiple times. This work highlights the urgent need for continuous monitoring of surviving populations and calls for immediate implementation of an effective protection and management strategy that will ensure the persistence of surviving individuals and the production of resistant offspring