Biodiversity and socio-environmental problems of the south-eastern Baltic coastal zone

The diversity of life occurs at several hierarchical levels of biological organisation, including the biotope (habitats) diversity. The knowledge of the coastal habitat diversity and its sensitivity to the anthropogenic impact is one of the most important preconditions for the sustainable use and development of the coastal regions. This paper gives a brief overview of a recent study, which was aimed to classify the Lithuanian coastal zone underwater habitats and identify anthropogenic threats to the area.     

21世纪美国地球科学领域关键需求

引言2012年9月17日,美国地球科学学会(AGI)向美国政府提交了政策建议报告《21世纪的关键需求:地球科学所发挥的作用》(Critical Needs for the Twenty-first Centu-ry:the Role of the Geosciences)。该报告根据当前及未来国家安全需要以及所面临的全球性挑战,提出了地球科学领域迫切需要关     

Pressure effects on regional mean sea level trends in the German Bight in the twenty-first century

The effect of large-scale atmospheric pressure changes on regional mean sea level projections in the German Bight in the twenty-first century are considered. A developed statistical model is applied to climate model data of sea level pressure for the twenty-first century to assess the potential contribution of large-scale atmospheric changes to future sea level changes in the German Bight. Using 78 experiments, an ensemble mean of 1.4-cm rise in regional mean sea level is estimated until the end of the twenty-first century. Changes are somewhat higher for realisations of the special report on emission scenarios (SRES) A1B and A2, but generally do not exceed a few centimeters. This is considerably smaller than the changes expected from steric and self-gravitational effects. Large-scale changes in sea level pressure are thus not expected to provide a substantial contribution to twenty-first century sea level changes in the German Bight.     

Dispersion in the Yucatan coastal zone: Implications for red tide events

The mechanisms governing dispersion processes in the northern Yucatan coast are investigated using a barotropic numerical model of coastal circulation, which includes wind-generated and large scale currents (i.e. Yucatan Current). This work provides the foundations for studying the dispersion of harmful algal blooms (HABs) in the area. Modelling experiments include effects of climatic wind (from long term monthly mean NCEP reanalysis), short term wind events (from in situ point measurements), and Yucatan Current (YC) characteristics. Its magnitude was approximated from published reports, and its trajectory from geostrophic current fields derived from altimeter data. These provided a range of real and climatic conditions to study the routes in which phytoplankton blooms may travel. The 2-D model results show that a synthetic and conservative bloom seeded in the Cabo Catoche (CC) region (where it usually grows), moves along the coast to the west up to San Felipe (SF), where it can either move offshore, or carry on travelling westwards. The transport to the west up to SF is greatly influenced by the trajectory, intensity and proximity of the YC jet to the peninsula, which enhances the westward circulation in the Yucatan Shelf. Numerical experiments show that patch dispersion is consistently to the west even under the influence of northerly winds. When the YC flows westward towards the Campeche Bank, momentum transfer caused by the YC jet dominates the dispersion processes over wind stress. On the other hand, when it flows closer to Cuba, the local processes (i.e. wind and bathymetry) become dominant. Coastal orientation and the Coriolis force may be responsible for driving the patch offshore at SF if external forcing decreases.     

Funding in integrated coastal zone management partnerships

In countries where integrated coastal zone management (ICZM) is not enshrined in statute, a voluntary approach has often been taken. This review examines issues relating to funding in ICZM partnerships, particularly the local coastal fora (LCF) network in the UK. It highlights the lack of sustainable long-term funding mechanisms for organisations with the core aim of sustainable management of coastal resources. The relative difficulty of raising funds for core costs as opposed to projects is addressed, as is the lack of business/industry involvement. The 'hamster wheel syndrome' of fundraising is noted, where staff spend too much time trying to raise money, as opposed to developing ICZM. The resultant impact on the staff and the operation of the LCF is considered. Examples beyond the UK are considered, as are the problems associated with 'pump-prime' funding and implementation. Is the lack of formality in ICZM the crux of the funding problem?     

SuperDARN: An example of a network approach to geospace science in the twenty-first century

The study of Earth's space environment, or geospace, has made considerable advances in the 50 years since the start of the Space Age, which was coincident with the 1957 International Geophysical Year. Space probes have visited most parts of that environment providing a wealth of in situ and remote-sensing measurements. Equally important in contributing to the advances made over the last 50 years have been the many instruments, which have been distributed on the surface of the Earth. In particular, the development of networks for the specific purpose of studying the dynamics of geospace, energy redistribution within geospace, and fundamental physical processes in plasmas has been hugely successful. Ground-based instruments remotely sense processes and phenomena in geospace and since this volume is large, networks of such instruments are the best way of measuring the global state of geospace and its dynamics. In this paper, I describe ways in which the Super Dual Auroral Radar Network (SuperDARN) has contributed to the success of ground-based networks, concentrating on science results, which have required the network approach so well demonstrated by SuperDARN. Such science includes the remote sensing of the reconnection electric field and its dynamics, the study of processes where asymmetries in the geospace system are induced by the external driving forces, and MHD waves, which play an important role in the transfer of energy and momentum within geospace. In addition, I discuss open science questions, which can be addressed by SuperDARN in the future, in particular in conjunction with current and future space missions as well as other ground-based networks.     

Ocean and atmosphere changes in the Caribbean Sea during the twenty-first century using CMIP5 models

Ocean Dynamics - Coastal communities around the Caribbean Sea are vulnerable to global warming impacts, partly because of constraints on their adaptive capacity. We use three climate models...     

Evaluating ecological quality in the north-eastern Black Sea coastal zone

Anthropogenic pressures have resulted in measurable impacts on the coastal ecosystems of the northern (Sevastopol Bay, Ukraine) and eastern (Batumi aquatoria, Georgia) Black Sea. Indices suggest that major impacts are relatively localized and are comparable to similar situations in the northern Atlantic. In contrast, biodiversity was appreciably lower than from comparable north Atlantic waters. The number of macrobenthic species was typically round 50, less than half the number that might be expected from similar exercises in US or European waters. Site-specific indices likewise indicated a somewhat lower diversity within communities, yielding metrics which would indicate a measure of stress in N. Atlantic situations. Microbial status was generally good, although regions close to urbanisation did not comply with standards laid down in the current EC Bathing Water Directive (76/EC/160). Likewise viruses were more commonly, although not exclusively, associated with urban locations, as were phages. Microbial investigation of the sediments confirmed the presence of heterotrophic and oil-oxidising bacteria. Abundance of the latter was closely correlated to the degree of oil contamination of the sediments, and to temperature, although for both, the results showed that the increase in bacterial abundance did level off beyond a certain point. Numbers of oil-oxidising bacteria in the water column displayed a classical response to temperature, with abundance doubling over a 10-degree C rise in temperature. Overall the results suggest that while indices in current use are useful in evaluating coastal quality in the Black Sea, some adjustments would be necessary especially in the establishment of baseline or reference values.     

Some hydrodynamic problems for a nepheloid zone

Summary A layer of a few hundred meters thickness with suspended matter (a nepheloid zone) was discovered byEwing andThorndike [4]³⁾ near the bottom on the continental slope of the North Atlantic. A downward pressure gradient is produced in this layer due to increment of water density with suspensoid. When only the Coriolis force balances with this pressure gradient, a bottom nepheloid current flows southwestward parallel to the depth contours with a velocity of about 10 (cm/sec) for a slope of one degree. The pressure gradient for fluid with locally variable density above a sloping bottom is treated and an extra term due to density gradient along the slope is derived. The vertical profiles of the nepheloid current with an effect on the vertical eddy viscosity are computed. Two kinds of vertical distributions of eddy viscosity are determined from the observed nepheloid distributions and used in the calculations: constant but different values at two layers and those increasing with height. The effect of the change of density along the bottom is treated by introducing dimensionless variables. Rossby number of the nepheloid current becomes about 10^–2 indicating inertia terms to be negligible. Rossby number of turbidity currents ranges from 2 (in a decaying area) to 5 (developing area), suggesting that inertia terms are more important than Coriolis terms. The trajectories of turbidity currents are computed from motion of a mass of mud under the Coriolis force and friction, and the results are applied to those inferred byHand andEmery [6] in the San Diego Through off California.LGO Contribution Number 925.     

Atrazine fate and transport within the coastal zone in southeastern Puerto Rico

Agrichemical transport to coastal waters may have adverse ecological impact. This work examined atrazine fate and transport in a field adjacent to Puerto Rico’s Jobos Bay National Estuarine Research Reserve. The herbicide’s use was linked to residue detection in shallow groundwater and movement toward the estuary; however, data indicated that transport via this pathway was small. In contrast, surface runoff as tropical storm systems moved through the area appeared to have high potential for atrazine transport. In this case, transport to the estuary was limited by runoff event timing relative to atrazine application and very rapid atrazine dissipation (DT₅₀ = 1–3 days) in field soil. Soil incubation studies showed that accelerated degradation conditions had developed in the field due to repeated atrazine treatment. To improve weed management, atrazine replacement with other herbicide(s) is recommended. Use of products that have greater soil persistence may increase runoff risk.     

Foraminiferal responses to polluted sediments in the Montevideo coastal zone, Uruguay

A study of foraminiferal assemblages was carried out in 24 sediment samples collected from the Montevideo coastal zone (south-eastern coastal region of South America) to assess the response of the benthic foraminifera to the polluted sediments. The area is affected by different pollutants such as sewage, hydrocarbons and heavy metals derived from different sources. Biological data were analyzed with multivariate techniques of cluster analysis and a principal component analysis (PCA) was performed for abiotic factors. The results allowed the recognition of different species assemblages corresponding to different sub-environments, which reflected the prevalent ecological conditions. The Montevideo Bay, particularly, its inner part showed an extremely poor foraminiferal fauna-including a totally azoic station-and high percentages of abnormal tests, when compared with the adjacent Punta Carretas and Punta Yeguas zones. Mean faunal density showed a strong relationship with organic matter, oxygen and heavy metal concentrations, as well as redox potential and pH values of each sub-environment. Although the adjacent zones presented a moderate pollution degree, it was noticed that a positive effect on the foraminiferal density specially on Ammonia tepida, caused by the sewage pipe located in Punta Carretas, a pure organic contamination. Differences among foraminiferal assemblages seemed to be related to the combined action of the several kinds of pollutants and the natural abiotic variables, like the rapid salinity changes that occurred in this area.     

Crustal microdeformations and tides in the coastal zone of the Sea of Japan

Based on experimental data and numerical modeling, the possible mechanisms of the effect of internal gravitational waves within the range of periods from tidal values to a few tens of minutes on crustal microdeformations in the coastal zone of the Sea of Japan are examined. The spectral analysis of oscillations in the sea level and microdeformations recorded in various seasons reveals common maximums of energy at diumal and semidiurnal periods, but the coincidence of the maximums at shorter periods is random and varies with time. The phase shifts between the surface tide and crustal deformations are also unstable in time. To explain the observed interrelations between the processes at sea and in the Earth’s crust, we modeled numerically the generation of internal tides, bores, and packets of short internal waves in terms of a nonlinear model of shallow water. It is shown that the observed effects can be caused (1) by the resonance between the wavelength of the internal tide and the shelf width and (2) by the reflection of bores and internal wave packets from a steep bottom and rocky shores or by their collapse.     

Excess protactinium in phosphate nodules from a coastal upwelling zone

Measurements of²³¹Pa/²³⁵U and²³⁰Th/²³⁴U activity ratios have been made for a suite of Quaternary age phosphate nodules from the upwelling zone off Peru and Chile. Many of these samples contain more²³¹Pa than would be predicted based on closed-system²³⁰Th/²³⁴U ages unlike samples from non-upwelling environments which have been shown to have concordant²³¹Pa and²³⁰Th ages. Peru/Chile phosphate nodules apparently pick up²³¹Pa preferentially to²³⁰Th. This is most likely a result of prior fractionation of protactinium and thorium in the open ocean. Highly productive coastal upwelling zones may be added to the growing list of localities where fractionation between thorium and protactinium isotopes has been observed in marine sediments.     

Prediction of sand transport rates by waves and currents in the coastal zone

The predictions of a sand transport research model and Bijker's (J. Waterways, Harbours Coastal Eng. Div. ASCE 97 (WW4) (1971) 687) engineering model are compared with data obtained in wave-current conditions at three field sites. A key element in the present study is that the bed roughness at the three sites has been estimated from predictions of the sand ripple dimensions. The comparisons between suspended sand concentrations and transport rates show that a considerable amount of uncertainty (factor ±5 or more) arises when individual predictions are compared with the measurements. However, the overall bias in each set of comparisons is smaller than this, with overall agreement being within a factor of ±2 in most cases. While the results demonstrate that research models, adapted for field application, may be used to make practical sand transport computations with as much accuracy as engineering formulations, the true benefit of research models lies in the improved understanding of transport processes that they provide. This is illustrated with reference to the mechanism of grain size sorting caused by oblique incidence of waves on a current.     

Microbial water quality of the Georgian coastal zone of the Black Sea

From 2006 to 2008, microbial water quality was monitored along the Georgian coast of the Black Sea. Temperature, pH, salinity, and dissolved oxygen were measured, along with a variety of aquatic microbial parameters, including heterotrophic plate count (HPC), total culturable bacterial count (TCBC), and chlorophyll a (Chl-a) concentration. Total and fecal coliforms and total enterococci counts were recorded as indicators of fecal pollution. Vibrio bacteria, and Escherichia coli- and Vibrio-specific bacteriophages were isolated and enumerated to determine their relationships to standard marine pollution indicators.Persistent microbial pollution was observed, particularly in the summer months, with a higher rate of contamination in estuaries. Microbial indicators generally showed seasonal dependence, suggesting that temperature may influence bacterial dynamics in this environment. No correlation was apparent between fecal pollution indicators and physical-chemical and aquatic microbial parameters, although there were significant relationships amongst the indicators themselves, as well as with the prevalence of Vibrio bacteria and phage.