The Baltic Sea environment and the European Union: Analysis of governance barriers

The EU enlargement brought the Baltic Sea into the sphere of EU environmental policymaking, making the sea, with the exception of Russia, an EU inland sea. Yet, the state of the Baltic Sea environment is deteriorating at an alarming pace. This paper describes the evolution of the EU governance of the Baltic Sea environment, focussing on governance barriers. The findings demonstrate how the choice of analytical lens influences the construction of governance barriers and the respective intervention strategies. Such understanding can help policy practitioners in their search for successful measures to improve the governance situation in the Baltic Sea region.     

A note on the economics of Swedish Baltic Sea fisheries

The cod stocks in the Baltic Sea are important not only for fisheries but for the entire ecosystem utilized by numerous stakeholders around the coast. All such activities have economic values. In this note the economics of the Swedish Baltic Sea cod fishery is estimated in relation to the sector's interaction with other users of the Baltic Sea ecosystem. The results show a negative resource rent for the fishery, € −5 million without public expenses (subsidies and administrative costs), and € −13 million including public expenses. The interactions between the fisheries and tourism, seal population, carbon dioxide emissions, recreational fishing, and discards are discussed, and when monetary estimates are available these are related to the estimated resource rent.     

论北极西北航道航行自由与环境保护的平衡路径

近年来,随着发展"绿色航运经济"的话题热度不断升温,北极西北航道因其潜在的巨大通航价值成为各国诉争的焦点,与此同时,船舶通行所带来的对海洋生态的侵蚀破坏,例如燃油废料和塑料垃圾等,引发了国际法视域内的诸多争议。以加拿大为代表的西北航道沿岸国滥用国际海洋法框架下关于航行自由和环境保护的模糊地带,肆意扩张国内法的管制范围对他国的航行自由进行不合理限制的问题愈加凸显。为了国际航海秩序的和平稳定,实现北极航运的可持续发展,文章以北极西北航道沿岸国借助"环境保护"名义限制他国在西北航道航行自由权的法律援引模式为切入,对航行安全控制区制度和特别敏感海域制度的法律争议进行分析,综合体系解释的方法和国际法实践判例的指引,构建北极西北航道航行自由与环境保护的平衡路径。     

Sweden and the Baltic Sea pipeline: Between ecology and economy

Building a submarine pipeline in the Baltic Sea to transport natural gas from Russia to Germany contradicts targets to reduce fossil fuel dependency and seems to ignore a long history of environmental challenges in the area. This article examines the tensions between the environmental, economic, and national security arguments framing the Swedish government decision to allow the pipeline to be laid on the Baltic seabed passing through the Swedish economic zone. At first sight, the decision seems to run contrary to Sweden's ambitious environmental policy. However, by framing the issue within a broader understanding of the country's tradition of consensual decision-making, and considering the tensions and contradictions inherent in policies for sustainable development, the permission fits well with the logic that, in case of conflict, economic growth is given priority even when the environment is at stake.     

Variability of Sea Surface Heights in the Baltic Sea: An Intercomparison of Observations and Model Simulations

Sea level changes in the Baltic Sea are dominated by internal, short-term variations that are mostly caused by the ephemeral nature of atmospheric conditions over the Baltic area. Tides are small and their influence decreases from western parts of the Baltic Sea to the Baltic Proper. Superimposed to the large short-term sea level changes (up to few decimeters from day to day) are seasonal and interannual variations (centimeters to decimeters). This study focuses on the comparison of sea surface heights obtained from observations and from a high resolution oceanographic model of the Baltic Sea. From this comparison, the accuracy of the modeled sea surface variations is evaluated, which is a necessary precondition for the further use of the oceanographic model in geodetic applications. The model reproduces all observed Baltic sea level variations very reliably with an accuracy of 5 to 9 cm (rms) for short-term variations (up to 2 months) and 8 cm (rms) for long-term variations (>2 months). An additional improvement of the model can be attained by including long-period sea level variations of the North Sea. The model performs well also in the case of extreme sea level events, as is shown for a major storm surge that occurred at the southern coast of the Baltic Sea in November 1995.     

Atmospheric Pb and Cd input into the Baltic Sea: a new estimate based on measurements

Bulk deposition samples were collected during a summer (1997) and a winter (1998) measurement campaign at four coastal stations along the southern Baltic Sea coast and on the Island of Gotland. The data were used to construct Pb and Cd deposition fields over the Baltic Sea. A weak gradient with decreasing deposition rates from the southwest towards the east and north was obtained for Pb. In the case of Cd, the spatial distribution pattern was characterized by an extreme deposition maximum at the Polish station on the Hel Peninsula. The total atmospheric input of Pb and Cd into the Baltic Sea was 550 and 33 t/year, respectively, and exceeds the riverine input by approximately about 50%. Previous measurement-based estimates were higher by a factor 2–3 and indicate a decrease of the atmospheric deposition during the past 10–15 years. The comparison with modelled deposition data yielded partly large differences and was impaired by the fact that 1990 emission inventories were used whereas our measurements were performed in 1997/1998.Relating our deposition estimate and the Pb/Cd input by rivers to the mean concentrations in Baltic Sea water, residence times of 0.29 and 3.6 years were obtained for Pb and Cd, respectively.     

44 Years Hindcast of the sea level and circulation in the Baltic Sea

The subject of the investigation was the multiyear hindcast of the sea level elevations and currents over the Baltic Sea. The approach follows to the HIPOCAS project conception and contained the 3D hydrodynamic model using boundary conditions from the atmosphere and catchment for 44-year period referring to the second half of the 20th century.     

海冰热力模式的辐射参数化方案在渤海和波罗的海应用的比较

研究了海冰热力模式中的各种辐射参数化方案,对比了模式计算的太阳短波辐射、大气长波辐射以及海冰热力变化,并利用渤海和波罗的海观测资料进行比较和误差分析.冬季大部分时间太阳短波辐射对海冰热力过程的作用有限.简单计算方案一般满足海冰模式要求.误差主要受云和冰雪表面与大气之间的多重反射影响.长波辐射对表面热平衡和海冰质量变化起重要作用.长波辐射参数化方案的计算结果受环境因素影响.云量参数化有待进一步改进.海冰模式计算结果的精度与长波辐射计算精度有一致性.     

Analysis of the water column oxic/anoxic interface in the Black and Baltic seas with a numerical model

A 1D hydrophysical-biogeochemical model was developed to study the cycling of the main elements in the pelagic redox layer in seas with anoxic conditions. The formation and decay of organic matter; the reduction and oxidation of nitrogen, sulfur, manganese, and iron species; and the transformation of phosphorus species were parameterized. Temporal and spatial developments of the model's variables were described by a system of horizontally integrated vertical diffusion equations for non-conservative substances. The calculated spatial and temporal distributions of the above-mentioned parameters were in good agreement with observed vertical distribution patterns of these processes.     

Time-series of surface water CO2 and oxygen measurements on a platform in the central Arkona Sea (Baltic Sea): Seasonality of uptake and release

High resolution measurements of carbon dioxide and oxygen were made in surface waters of the central Arkona Sea (Baltic Sea) from May 2003 to September 2004. Sensors for CO₂ partial pressure (pCO₂^w) and oxygen (O₂) concentration were mounted in 7 m depth on a moored platform which is used for hydrographic and meteorological monitoring. The pCO₂^w data were obtained in half hour intervals and O₂ was measured each hour as an average of a 10 min measurement. To check the performance of the sensors, pCO₂^w and O₂ were determined by shipboard measurements on a research vessel which visited the site in 1–2 month intervals. In addition, pCO₂^w was measured on a “volunteer observing ship” (VOS) passing the platform each second day at a distance of about 25 km. Minima of 220 to 250 μatm of pCO₂^w were observed at the time of the spring bloom and a cyanobacteria bloom in mid-summer. During winter the pCO₂^w was mostly close to equilibrium with the atmosphere but maxima of 430 to 530 μatm were also observed. The seasonality of oxygen and pCO₂^w showed an opposing pattern. From a multiple regression analysis, we concluded that two processes primarily controlled pCO₂^w during our study: biological turnover and mixing. A parameterization, based on apparent oxygen utilisation (AOU) and salinity (S) only (pCO₂^w = 1.23 AOU + 43 S), reproduced the seasonality of pCO₂^w in surface water reasonably well. Based on our pCO₂, salinity, and temperature data set, we attempted to separate processes changing total inorganic carbon concentrations (C_T) by using an alkalinity–salinity relation for the area. The contribution of CO₂ gas exchange and mixing were calculated and from this the biological turnover was deduced to reveal the calculated C_T changes.The net annual uptake of CO₂ in the central Arkona Sea was estimated to be about 1.5 Tg (1.5·10¹² g) which was approximately balanced by a net oxygen release considering the uncertainties of the flux calculations. Near-coast CO₂ emission due to episodic upwelling partly compensated the uptake of the central part of the Arkona Sea reducing the overall magnitude of the CO₂ uptake.     

Geophysics of sea ice in the Baltic Sea: A review

With improved observation methods, increased winter navigation, and increased awareness of the climate and environmental changes, research on the Baltic Sea ice conditions has become increasingly active. Sea ice has been recognized as a sensitive indicator for changes in climate. Although the inter-annual variability in the ice conditions is large, a change towards milder ice winters has been detected from the time series of the maximum annual extent of sea ice and the length of the ice season. On the basis of the ice extent, the shift towards a warmer climate took place in the latter half of the 19th century. On the other hand, data on the ice thickness, which are mostly limited to the land-fast ice zone, basically do not show clear trends during the 20th century, except that during the last 20 years the thickness of land-fast ice has decreased. Due to difficulties in measuring the pack-ice thickness, the total mass of sea ice in the Baltic Sea is, however, still poorly known. The ice extent and length of the ice season depend on the indices of the Arctic Oscillation and North Atlantic Oscillation. Sea ice dynamics, thermodynamics, structure, and properties strongly interact with each other, as well as with the atmosphere and the sea. The surface conditions over the ice-covered Baltic Sea show high spatial variability, which cannot be described by two surface types (such as ice and open water) only. The variability is strongly reflected to the radiative and turbulent surface fluxes. The Baltic Sea has served as a testbed for several developments in the theory of sea ice dynamics. Experiences with advanced models have increased our understanding on sea ice dynamics, which depends on the ice thickness distribution, and in turn redistributes the ice thickness. During the latest decade, advance has been made in studies on sea ice structure, surface albedo, penetration of solar radiation, sub-surface melting, and formation of superimposed ice and snow ice. A high vertical resolution has been found as a prerequisite to successfully model thermodynamic processes during the spring melt period. A few observations have demonstrated how the river discharge and ice melt affect the stratification of the oceanic boundary layer below the ice and the oceanic heat flux to the ice bottom. In general, process studies on ice–ocean interaction have been rare. In the future, increasingly multidisciplinary studies are needed with close links between sea ice physics, geochemistry and biology.     

Vertical Patterns of Suspended Matter Characteristics Along a Coastal-basin Transect in the Western Baltic Sea

Suspended particulate matter samples were collected from the water column, the bottom nepheloid layer and the ‘ fluffy layer ’ from four stations along a coastal-basin transect in the Pomeranian Bight, western Baltic Sea. Sampling was performed nine times between October 1996 and December 1998 for various analyses, including electron probe x-ray micro analysis for detailed mineralogical investigations.Specific vertical patterns of clay mineral distributions were found. Suspended particulate matter (SPM) in the bottom nepheloid layer and the ‘ fluffy layer ’ overlying sediments was enriched in organic carbon and hydrated three layer clay minerals, whereas the non-aggregated SPM was dominated by quartz and biogenic opal. It appears that separation effects operate during aggregation of mineral particles and organic matter in repeated cycles of resuspension and settling. No clear seasonal variations in the composition of the SPM were found, in spite of high spatial and temporal variability of biological and physical variables. The results suggest that preferential incorporation, possibly aided by microbiological colonization, of hydrated three layer silicates into the organic flocs is a process that occurs under a wide range of conditions. Because aggregates sink faster than individual particles, aggregate formation led to a relative enrichment of illite and smectite in the near-bottom layers. Considering the affinity of organic contaminants and heavy metals to organic matter, the selective removal of aggregated organic matter and hydrated three-layer clay minerals from the water column and enhanced transport in the near-bottom fluffy layer may be a natural cleansing mechanism operating in the shallow waters of the bight.     

Activity Concentrations and Fluxes of Radiocesium in the Southern Baltic Sea

The activity concentrations of dissolved¹³⁷Cs have been determined in the water column and¹³⁷Cs and¹³⁴Cs in the sediments and the sediment porewaters of the southern Baltic Sea. The mean activity concentration of dissolved¹³⁷Cs in the Gdansk Deep declined from 109 Bq m⁻³in June 1986 to 61 Bq m⁻³in 1999. In sediments, the activity concentrations of¹³⁷Cs (33-231 Bq kg⁻¹) were highest in muds and the activity concentrations of¹³⁴Cs were about 6% of the total Cs activity. The Chernobyl contribution to¹³⁷Cs activity was between 43% and 77%. The porewater activity concentrations of¹³⁷Cs in muddy sediments were in the range 71 to 3900 Bq m⁻³and were higher than those in the overlying seawater. The diffusive flux of dissolved¹³⁷Cs from the muddy sediments was estimated in the range 5 to 480 Bq m⁻²year⁻¹. The flux of¹³⁷Cs from sediment porewaters of the southern Baltic Sea was about 45% of the total, including fluxes of¹³⁷Cs from wet and dry atmospheric deposition and the fluvial inputs. The results were used to elucidate the rate of recovery of the sediments and the waters of the southern Baltic from Chernobyl-derived¹³⁷Cs.     

RNA:DNA ratios of Baltic Sea herring larvae and copepods in embayment and open sea habitats

Elucidation of important nursery habitats for young fish can aid in the management and assessment of fish stocks. Herring (Clupea harengus) in the Baltic Sea primarily spawn in coastal areas, but larvae are also present in off-shore, open sea areas. To investigate if sheltered coastal habitats provide a better growth environment for larval herring, we compared short-term growth (as indexed by whole body RNA:DNA ratios) of larval herring from three habitat types of the northwest Baltic proper (sheltered inner bay, exposed outer bay, and open sea). In addition, we compared individual RNA content of adult female Eurytemora affinis (a common Baltic copepod) among these different habitats. High RNA levels in these copepods indicate high production of nauplii, which are important food for larval herring. Both RNA:DNA ratios of larval herring and RNA content of E. affinis were significantly greater in embayment habitats, suggesting that the sheltered coastal areas are high quality nursery habitats for young Baltic herring.     

Photochemical production of ammonium and transformation of dissolved organic matter in the Baltic Sea

The release of ammonium from the photochemical degradation of dissolved organic matter (DOM) has been proposed by earlier studies as a potentially important remineralisation pathway for refractory organic nitrogen. In this study the photochemical production of ammonium from Baltic Sea DOM was assessed in the laboratory. Filtered samples from the Bothnian Bay, the Gulf of Finland and the Arkona Sea were exposed to UVA light at environmentally relevant levels, and the developments in ammonium concentrations, light absorption, fluorescence and molecular size distribution were followed. The exposures resulted in a decrease in DOM absorption and loss of the larger sized fraction of DOM. Analysis of the fluorescence properties of DOM using parallel factor analysis (PARAFAC) identified 6 independent components. Five components decreased in intensity as a result of the UVA exposures. One component was produced as a result of the exposures and represents labile photoproducts derived from terrestrial DOM. The characteristics of DOM in samples from the Bothnian Bay and Gulf of Finland were similar and dominated by terrestrially derived material. The DOM from the Arkona Sea was more autochthonous in character. Photoammonification differed depending on the composition of DOM. Calculated photoammonification rates in surface waters varied between 121 and 382 μmol NH₄⁺ L^− 1 d^− 1. Estimated areal daily production rates ranged between 37 and 237 μmol NH₄⁺ m^− 2 d^− 1, which are comparable to atmospheric deposition rates and suggest that photochemical remineralisation of organic nitrogen may be a significant source of bioavailable nitrogen to surface waters during summer months with high irradiance and low inorganic nitrogen concentrations.     

Environmental genotoxicity and cytotoxicity in the offshore zones of the Baltic and the North Seas

Micronuclei (MN), nuclear buds (NB) and fragmented-apoptotic cells (FA) were analyzed in mature peripheral blood and immature cephalic kidney erythrocytes of flounder (Platichthys flesus), dab (Limanda limanda) and cod (Gadus morhua) from 12 offshore sites in the Baltic Sea (479 specimens) and 11 sites in the North Sea (291 specimens), which were collected during three research vessel cruises in December 2002, 2003 and in September 2004. The highest levels of environmental genotoxicity (frequencies of MN up to 0.5‰, NB – up to 0.75‰) and cytotoxicity (FA – up to 0.53‰) were observed in flatfishes from areas close to oil and gas platforms in the North Sea and in zones related to the extensive shipping and potentially influenced by contamination from large European Rivers (Elbe, Vistula, Oder). In dab from the offshore zones of the North Sea, the levels of nuclear abnormalities were higher as compared to those in dab from the Baltic Sea. Responses in immature kidney erythrocytes were higher than in mature erythrocytes from peripheral blood. MN frequency lower than 0.05‰ (the Baltic Sea) and lower than 0.1‰ (the North Sea) could be suspected as a reference level in the peripheral blood erythrocytes of flatfish.     

我国围填海和自然岸线生态环境监管现状及对法律修订的建议

为加强海洋生态环境保护,强化围填海和自然岸线生态环境监管制度建设,切实解决我国围填海的突出生态环境问题,文章基于2002—2018年全国围填海和自然岸线现状,分析当前我国围填海和自然岸线生态环境监管存在的不足,并提出具有针对性的对策建议。研究结果表明:全国大陆自然岸线保有率达标形势严峻;违规审批、处罚不力和监管不到位等导致大量围填海闲置以及自然岸线受损严重等问题;法律层面的滞后是造成监管不足的因素之一,建议尽快启动《中华人民共和国海洋环境保护法》的修订工作,从强化围填海事前审查、完善围填海事中事后监管、加强自然岸线监管保护、提高围填海生态环境损害成本和强化地方监管责任5个方面完善法律制度建设。     

Effects of water exchange and vegetation on the macroinvertebrate fauna composition of shallow land-uplift bays in the Baltic Sea

Shallow bays with soft sediment bottoms are common habitats along the Swedish and Finnish Baltic Sea coastline. These bays undergo a process of geomorphometric evolution with the natural isostatic land-uplift process, whereby open bays and sounds decrease in depth and are gradually isolated from the sea, forming bays with narrow openings. This study tested the relationship between the morphometric isolation of the bays from the sea and the macroinvertebrate fauna community of these bays. Additionally, we tested the specific role of the submerged vegetation as an indicator of the macroinvertebrate fauna community. We chose two environmental factors for the analyses, water exchange of the bays and the taxon richness of the macroflora in the bays. We found a hierarchical relationship between water exchange, flora taxon richness, and fauna biomass and taxon richness using structural equation modelling: decreased biomass and taxon richness of fauna were related to decreased flora taxon richness, which in turn was related to decreased water exchange. Using multivariate redundancy analysis, the two environmental factors included in the model were found to explain 47.7% of the variation in the fauna taxon composition and 57.5% of the variation in the functional feeding groups of the fauna. Along the morphometric isolation gradient of the bays, the fauna assemblages changed from a community dominated by gastropods, bivalves, and crustaceans, to a community mainly consisting of a few insect taxa. Moreover, the proportion of predators, gathering collectors, and shredders increased while that of filtering collectors and scrapers decreased. Our results indicate that the density and taxon richness of macroinvertebrate fauna are higher in less morphometrically isolated bays than in more isolated bays in the Baltic Sea. Furthermore, we suggest that the taxon richness of macroflora can serve as an indicator of the fauna community.