Assessment of Ecosystem Services Provided by Macrophytes in Southern Baltic and Southern Mediterranean Coastal Lagoons.

The ecological importance of macrophytes is well known and reflected in nature protection law, for example, as a key biological quality element. However, the socio-economic role, such as the impact of macrophyte presence on recreational activities, is often overlooked. The purpose of this study was to assess the human benefits (or ecosystem services) provided by macrophytes. We developed a list of 25 macrophyte ecosystem services and 79 assessment indicators based on expert knowledge and literature data. First, hypothetical scenarios of coastal lagoons were developed to assess the impact of different ecological states (i.e., macrophyte coverage) and management measures (i.e., fisheries) on the ecosystem service provision. Scenario assessments were carried out by stakeholder workshops and literature search. Second, the ecosystem service potential of submerged and emergent macrophyte habitats were assessed by macrophyte experts and literature data. Results showed that cultural services are most important in terms of the overall actual provision of ecosystem services (scenario assessment) but also showing highest potential of the hypothetical ecosystem service provision (habitat assessment). Highest overall potential is shown for reeds and tall forb communities (83 out of maximum 125), followed by seagrass beds (71) and seaweed communities (61). Our ecosystem service assessment approaches (i.e., scenario and habitat-based) using socio-cultural data (i.e., stakeholders and experts-based) and biophysical data (i.e., indicators-based) can serve as supportive tools for coastal management and policy implementation visualizing the benefits of macrophytes to humans.

A New Monitoring Strategy of Large Micro-, Meso- and Macro-Litter: A Case Study on Sandy Beaches of Baltic Lagoons and Estuaries.

Coastal lagoons and estuaries are hot spots to accumulate river basin-related plastic leakage. However, no official methodology exists to investigate their relatively short, rich in organic matter beaches, and the knowledge of pollution of lagoons is scarce worldwide. This study aimed to develop a methodology suitable for large micro (2-5 mm), meso (5-25 mm), and macro-litter (>25 mm) monitoring at sandy inner-coastal waters that would provide comparable results to the intensively used OSPAR 100 m method. The method proposed in this study is based on two 40 m2 rectangular polygons placed on the tidal accumulation zone for macro-litter enumeration and two 1 m2 squares for micro- and meso-litter. This method has been applied to 23 beaches from three inner-coastal waters of the Baltic Sea. This study shows that the litter densities between lagoons and bays differ and depend on the river output intensity and the retention capacity. The "Construction material", "Plastic pieces 2-5 mm", and "Plastic pieces 5-25 mm" were among this study's top ten most common litter items. Experts allocated these items to the "Land based industry and trade" source, which indicates that lagoons and bays through the connection of the major rivers could be a potential sink of land-based litter. An evident strength of the methodology established is the capability to determine litter of all sizes, low-cost and time-efficiency, implementable for volunteer-based monitoring; provides comparable results to the most commonly used methods for investigating litter pollution on coastal beaches.

Aerial and underwater drones for marine litter monitoring in shallow coastal waters: factors influencing item detection and cost-efficiency.

Although marine litter monitoring has increased over the years, the pollution of coastal waters is still understudied and there is a need for spatial and temporal data. Aerial (UAV) and underwater (ROV) drones have demonstrated their potential as monitoring tools at coastal sites; however, suitable conditions for use and cost-efficiency of the methods still need attention. This study tested UAVs and ROVs for the monitoring of floating, submerged, and seafloor items using artificial plastic plates and assessed the influence of water conditions (water transparency, color, depth, bottom substrate), item characteristics (color and size), and method settings (flight/dive height) on detection accuracy. A cost-efficiency analysis suggests that both UAV and ROV methods lie within the same cost and efficiency category as current on-boat observation and scuba diving methods and shall be considered for further testing in real scenarios for official marine litter monitoring methods.

An Impact Assessment of Beach Wrack and Litter on Beach Ecosystem Services to Support Coastal Management at the Baltic Sea.

As accumulation zones, sandy beaches are temporal sinks for beach wrack and litter, both often seen as nuisances to tourists. Consequently, there is a need for beach management and an enhanced political interest to evaluate their ecosystem services. We applied a new online multidisciplinary assessment approach differentiating between the provision, potential, and flow at German and Lithuanian beaches (Southern Baltic Sea). We selected a set of services and assessed four beach scenarios developed accordingly to common management measures (different beach wrack and litter accumulations). We conducted comparative assessments involving 39 external experts using spread-sheets and workshops, an online survey as well as a combined data-based approach. Results indicated the relative importance of cultural (52.2%), regulating and maintenance (37.4%), and provisioning services (10.4%). Assessed impact scores showed that the removal of beach wrack is not favorable with regard to the overall ecosystem service provision. Contrarily, the removal of litter can increase the service flow significantly. When removing beach wrack, synergies between services should be used, i.e., use of biomass as material or further processing. However, trade-offs prevail between cultural services and the overall provision of beach ecosystem services (i.e., coastal protection and biodiversity). We recommend developing new and innovative beach cleaning techniques and procedures, i.e., different spatio-temporal patterns, e.g., mechanical vs. manually, daily vs. on-demand, whole beach width vs. patches. Our fast and easy-to-apply assessment approach can support decision-making processes within sustainable coastal management allowing us to show and compare the impacts of measures from a holistic ecosystem services perspective.

Emission, Transport, and Deposition of visible Plastics in an Estuary and the Baltic Sea-a Monitoring and Modeling Approach.

AIM: was to assess whether a comprehensive approach linking existing knowledge with monitoring and modeling can provide an improved insight into coastal and marine plastics pollution. We focused on large micro- and mesoplastic (1-25 mm) and selected macroplastic items. Emission calculations, samplings in the Warnow river and estuary (water body and bottom sediments) and a flood accumulation zone monitoring served as basis for model simulations on transport and behavior in the entire Baltic Sea. Considered were the most important pathways, sewage overflow and stormwater. The coastline monitoring together with calculations allowed estimating plastics emissions for Rostock city and the Warnow catchment. Average concentrations at the Warnow river mouth were 0.016 particles/m³ and in the estuary 0.14 particles/m³ (300 µm net). The estuary and nearby Baltic Sea beaches were hot-spots for plastic accumulation with 6-31 particles/m². With increasing distance from the estuary, the concentrations dropped to 0.3 particles/m². This spatial pattern, the plastic pollution gradients and the observed annual accumulation values were consistent with the model results. Indicator items for sewer overflow and stormwater emissions exist, but were only found at low numbers in the environment. The considered visible plastics alone can hardly serve as indicator for microplastic pollution (<1 mm). The use of up-scaled emission data as input for Baltic Sea model simulations provided information on large scale emission, transport and deposition patterns of visible plastics. The results underline the importance of plastic retention in rivers and estuaries.

-Blue mussel (Mytilus spp.) cultivation in mesohaline eutrophied inner coastal waters: mitigation potential, threats and cost effectiveness.

The EU-water framework directive (WFD) focuses on nutrient reductions to return coastal waters to the good ecological status. As of today, many coastal waters have reached a steady state of insufficient water quality due to continuous external nutrient inputs and internal loadings. This study focuses first on the current environmental status of mesohaline inner coastal waters to illustrate their needs of internal measures to reach demanded nutrient reductions and secondly, if mussel cultivation can be a suitable strategy to improve water quality. Therefore, nitrogen, phosphorus, chlorophyll a, and Secchi depth of nine mesohaline inner coastal waters in north east Germany were analyzed from 1990 to 2018. Two pilot mussel farms were used to evaluate their effectiveness as a mitigation measure and to estimate potential environmental risks, including the interactions with pathogenic vibrio bacteria. Further, estimated production and mitigation potential were used to assess economic profitability based on the sale of small sized mussels for animal feed and a compensation for nutrient mitigation. The compensation costs were derived from nutrient removal costs of a waste water treatment plant (WWTP). Results show that currently all nine water bodies do not reach the nutrient thresholds demanded by the WFD. However, coastal waters differ in nutrient pollution, indicating that some can reach the desired threshold values if internal measures are applied. The mitigation potential of mussel cultivation depends on the amount of biomass that is cultivated and harvested. However, since mussel growth is closely coupled to the salinity level, mussel cultivation in low saline environments leads to lower biomass production and inevitably to larger cultivation areas. If 50% of the case study area Greifswald Bay was covered with mussel farms the resulting nitrogen reduction would increase Secchi depth by 7.8 cm. However, high chlorophyll a values can hamper clearance rates (<20 mg m-3 = 0.43 l h-1 dry weight g-1) and therefore the mitigation potential. Also, the risk of mussel stock loss due to high summer water temperatures might affect the mitigation potential. The pilot farms had no significant effect on the total organic content of sediments beneath. However, increased values of Vibrio spp. in bio deposits within the pilot farm (1.43 106 ± 1.10 106CFU 100 ml-1 (reference site: 1.04 106 ± 1.45 106 CFU 100 ml-1) were measured with sediment traps. Hence, mussel farms might act as a sink for Vibrio spp. in systems with already high vibrio concentrations. However, more research is required to investigate the risks of Vibrio occurrence coupled to mussel farming. The economic model showed that mussel cultivation in environments below 12 PSU cannot be economic at current market prices for small size mussels and compensations based on nutrient removal cost of WWTPs.

Decision-Support Tools Used in the Baltic Sea Area: Performance and End-User Preferences.

Decision-support tools (DSTs) synthesize complex information to assist environmental managers in the decision-making process. Here, we review DSTs applied in the Baltic Sea area, to investigate how well the ecosystem approach is reflected in them, how different environmental problems are covered, and how well the tools meet the needs of the end users. The DSTs were evaluated based on (i) a set of performance criteria, (ii) information on end user preferences, (iii) how end users had been involved in tool development, and (iv) what experiences developers/hosts had on the use of the tools. We found that DSTs frequently addressed management needs related to eutrophication, biodiversity loss, or contaminant pollution. The majority of the DSTs addressed human activities, their pressures, or environmental status changes, but they seldom provided solutions for a complete ecosystem approach. In general, the DSTs were scientifically documented and transparent, but confidence in the outputs was poorly communicated. End user preferences were, apart from the shortcomings in communicating uncertainty, well accounted for in the DSTs. Although end users were commonly consulted during the DST development phase, they were not usually part of the development team. Answers from developers/hosts indicate that DSTs are not applied to their full potential. Deeper involvement of end users in the development phase could potentially increase the value and impact of DSTs. As a way forward, we propose streamlining the outputs of specific DSTs, so that they can be combined to a holistic insight of the consequences of management actions and serve the ecosystem approach in a better manner.

Cigarette butts on Baltic Sea beaches: Monitoring, pollution and mitigation measures.

OSPAR, Rake and Flood accumulation zone methods were applied at 29 beaches of the German and Lithuanian Baltic Sea coast (2011-2018) to monitor cigarette butt pollution. Also, butt pollution prevention measure - ballot bin, was tested. The number of cigarette butts was significantly higher in Germany than in Lithuania, but the percent of butts from total litter items was similar. Rake method turned out to be suitable for cigarette butt assessment, while the OSPAR method underestimates the butt pollution. The visitor number on the beach had a significant effect on the cigarette butt number: in remote beaches, without visitors, usually, no butts were observed, while the highest number and the percent of butts were observed in beaches with the highest number of visitors. The ballot bin campaign may have increased the public awareness about pollution, but turned out to be in-efficient in reducing it.

Cost-effective monitoring of large micro- and meso-litter in tidal and flood accumulation zones at south-western Baltic Sea beaches.

Often, beach litter monitoring strategies focus only on macro-litter (>25 mm) and do not distinguish between litter left at beaches and litter washed up onshore. We tested inexpensive and user-friendly methods to examine meso-litter (5-25 mm) and large micro-litter (2-5 mm) washed up on German sandy beaches and evaluated our methods regarding the requirements of the Marine Strategy Framework Directive. With a sieve accumulation zone monitoring method, tested 41 times, we found 0.2-21.2 litter pieces/m2 (⌀ 5.3 pieces/m2 ±â€¯8.9). With a bare eye accumulation zone monitoring method, tested 10 times, at other beaches, 9.1-65.6 litter pieces/m2 (⌀ 31.8 pieces/m2 ±â€¯15.7) were found. Both methods are inexpensive, useful for volunteers, and can be carried out quickly, but are also limited, as they cannot be used regularly. A tested webcam and a modified Braun-Blanquet method turned out to be less suitable.

First findings of potentially human pathogenic bacteria Vibrio in the south-eastern Baltic Sea coastal and transitional bathing waters.

Vibrio spp. are bacteria that inhabit fresh and marine waters throughout the world and can cause severe infections in humans. This study aimed to investigate the presence of potentially pathogenic Vibrio bacteria in the coastal waters of the Lithuanian Baltic Sea and the Curonian Lagoon. The results of cultivation on TCBS media showed that total abundance of Vibrio spp. varied from 1.2 × 102 to 6 × 104 CFU L-1. Real-time PCR revealed that the V. vulnificus vvhA gene varied from 2.8 × 103 to 3.7 × 104 copies L-1, with the highest amounts in sites with average water salinity of 7.1 PSU. Both green and blue-green algae and lower salinity play a role in the growth and spread of total Vibrio spp. Although potential infection risk was low at the time of this study, regular monitoring of Vibrio spp. and infection risk assessments are recommended.

Long term development of Bathing Water Quality at the German Baltic coast: spatial patterns, problems and model simulations.

Bathing water quality plays a key role for public health, is highly important for recreational tourism and therefore monitored in the EU-Directive 2006/7/EC. To identify pollution hot spots, sources and impacts of the directive-change in 2006, including a change of indicator organisms, we evaluated monitoring data of the past 15 years, collected own data, determined survival rates of indicator organisms and applied hydrodynamic modelling in a micro-tidal-system. Due to higher survival rates under turbid conditions and restricted water exchange, shallow, eutrophic bays and lagoons are hot spots of microbial pollution. Rain events cause high microbial emission and distribution. Based on different decay rates, the ratio of E. coli to Enterococci can hint towards a pollution source. Including rain predictions, currents and winds, hydrodynamic models can then assess the daily risk of microbial pollution at each bathing site. They are an important tool to modify beach management and event-based monitoring.

Analysis of environmental microplastics by vibrational microspectroscopy: FTIR, Raman or both?

The contamination of aquatic ecosystems with microplastics has recently been reported through many studies, and negative impacts on the aquatic biota have been described. For the chemical identification of microplastics, mainly Fourier transform infrared (FTIR) and Raman spectroscopy are used. But up to now, a critical comparison and validation of both spectroscopic methods with respect to microplastics analysis is missing. To close this knowledge gap, we investigated environmental samples by both Raman and FTIR spectroscopy. Firstly, particles and fibres >500 µm extracted from beach sediment samples were analysed by Raman and FTIR microspectroscopic single measurements. Our results illustrate that both methods are in principle suitable to identify microplastics from the environment. However, in some cases, especially for coloured particles, a combination of both spectroscopic methods is necessary for a complete and reliable characterisation of the chemical composition. Secondly, a marine sample containing particles <400 µm was investigated by Raman imaging and FTIR transmission imaging. The results were compared regarding number, size and type of detectable microplastics as well as spectra quality, measurement time and handling. We show that FTIR imaging leads to significant underestimation (about 35 %) of microplastics compared to Raman imaging, especially in the size range <20 µm. However, the measurement time of Raman imaging is considerably higher compared to FTIR imaging. In summary, we propose a further size division within the smaller microplastics fraction into 500-50 µm (rapid and reliable analysis by FTIR imaging) and into 50-1 µm (detailed and more time-consuming analysis by Raman imaging). Graphical Abstract Marine microplastic sample (fraction <400 µm) on a silicon filter (middle) with the corresponding Raman and IR images.

Escherichia coli pollution in a Baltic Sea lagoon: a model-based source and spatial risk assessment.

Tourism around the Oder (Szczecin) Lagoon, at the southern Baltic coast, has a long tradition, is an important source of income and shall be further developed. Insufficient bathing water quality and frequent beach closings, especially in the Oder river mouth, hamper tourism development. Monitoring data gives only an incomplete picture of Escherichia coli (E. coli) bacteria sources, spatial transport patterns, risks and does neither support an efficient bathing water quality management nor decision making. We apply a 3D ocean model and a Lagrangian particle tracking model to analyse pollution events and to obtain spatial E. coli pollution maps based on scenario simulations. Model results suggests that insufficient sewage treatment in the city of Szczecin is the major source of faecal pollution, even for beaches 20km downstream. E. coli mortality rate and emission intensity are key parameters for concentration levels downstream. Wind and river discharge play a modifying role. Prevailing southwestern wind conditions cause E. coli transport along the eastern coast and favour high concentration levels at the beaches. Our simulations indicate that beach closings in 2006 would not have been necessary according to the new EU-Bathing Water Quality Directive (2006/7/EC). The implementation of the new directive will, very likely, reduce the number of beach closings, but not the risk for summer tourists. Model results suggest, that a full sewage treatment in Szczecin would allow the establishment of new beaches closer to the city (north of Dabie lake).