Enhanced turbulence driven by mesoscale motions and flow-topography interaction in the Denmark Strait Overflow plume

The Denmark Strait Overflow (DSO) contributes roughly half to the total volume transport of the Nordic overflows. The overflow increases its volume by entraining ambient water as it descends into the subpolar North Atlantic, feeding into the deep branch of the Atlantic Meridional Overturning Circulation. In June 2012, a multiplatform experiment was carried out in the DSO plume on the continental slope off Greenland (180 km downstream of the sill in Denmark Strait), to observe the variability associated with the entrainment of ambient waters into the DSO plume. In this study, we report on two high-dissipation events captured by an autonomous underwater vehicle (AUV) by horizontal profiling in the interfacial layer between the DSO plume and the ambient water. Strong dissipation of turbulent kinetic energy of O( math formula) W kg−1 was associated with enhanced small-scale temperature variance at wavelengths between 0.05 and 500 m as deduced from a fast-response thermistor. Isotherm displacement slope spectra reveal a wave number-dependence characteristic of turbulence in the inertial-convective subrange ( math formula) at wavelengths between 0.14 and 100 m. The first event captured by the AUV was transient, and occurred near the edge of a bottom-intensified energetic eddy. Our observations imply that both horizontal advection of warm water and vertical mixing of it into the plume are eddy-driven and go hand in hand in entraining ambient water into the DSO plume. The second event was found to be a stationary feature on the upstream side of a topographic elevation located in the plume pathway. Flow-topography interaction is suggested to drive the intense mixing at this site

Upwelling events, coastal offshore exchange, links to biogeochemical processes - Highlights from the Baltic Sea Sciences Congress at Rostock University, Germany, 19-22 March 2007

The Baltic Sea Science Congress was held at Rostock University, Germany, from 19 to 22 March 2007. In the session entitled"Upwelling events, coastal offshore exchange, links to biogeochemical processes" 20 presentations were given,including 7 talks and 13 posters related to the theme of the session.This paper summarises new findings of the upwelling-related studies reported in the session. It deals with investigationsbased on the use of in situ and remote sensing measurements as well as numerical modelling tools. The biogeochemicalimplications of upwelling are also discussed.Our knowledge of the fine structure and dynamic considerations of upwelling has increased in recent decades with the advent ofhigh-resolution modern measurement techniques and modelling studies. The forcing and the overall structure, duration and intensity ofupwelling events are understood quite well. However, the quantification of related transports and the contribution to the overall mixingof upwelling requires further research. Furthermore, our knowledge of the links between upwelling and biogeochemical processes is stillincomplete. Numerical modelling has advanced to the extent that horizontal resolutions of c. 0.5 nautical miles can now be applied,which allows the complete spectrum of meso-scale features to be described. Even the development of filaments can be describedrealistically in comparison with high-resolution satellite data.But the effect of upwelling at a basin scale and possible changes under changing climatic conditions remain open questions

Практичні аспекти зменшення фрагментації ареалів тварин для проектів удосконалення інфраструктури

A transport network is an artificial component of the human environment, which causes a range of negative impacts on other living organisms, including violation of animal habitats integrity. Ability to move in search of food, shelter or mating, is negatively limited by obstacles that isolate the habitat. The term "habitat fragmentation" includes breaking habitat into several smaller patches, reduction in the total area of the habitat, decrease of the interior/edge ratio, and isolation of one habitat fragment from others. Consequently, roads divide habitats and create barriers that impede wildlife mobility, increasing instances of wildlife-vehicle collisions, which put both people and non-human animals at risk; landscape fragmentation can also result in genetic isolation, putting some species of wildlife at long term risk of extinction. Secondary effects from infrastructure development are further emergence of human settlements or industrial development, which put people and their activity closer to wildlife. In order to reduce the negative impacts of roads, the measures that directly reduce fragmentation by providing links between habitats, namely wildlife crossing structures or fauna passages should be implemented. The pilot area at the highway M-03 from Poltava to Kharkiv between 341 and 472 km planned for reconstruction under the World Bank project was analyzed based on spatial ecosystem approach to define the points of increased concern for the protection of habitats. Mitigation measures, in particular fauna passages, are necessary as the given road bisects important elements of eco-network: Galytsko-Slobozhansky natural latitudinal corridor and Vorskla regional eco-corridor. Five sites were chosen on the territory to provide wildlife mobility improvement with the help of such crossing structures, as landscape bridge, river crossing, joint-use underpass, underpass for small- and medium-sized animals, and multi-use overpass. The selection of the most appropriate type of fauna passage was based on the analysis of landscape structure, type of habitats affected and target species (their living needs, behaviour and preferred moving media). The suggested scheme of wildlife crossings is provided with recommendations on the design of the offered structures, their dimensions, construction materials and elements, as well as details about model target species and their nature conservation status. The cost of the project is supposed to be acceptable as it basically involves transformation of the existing infrastructure elements.Розглянуто негативні впливи транспортної мережі на живі організми в зоні її розташування. Зазначено, що дороги порушують цілісність ареалів тварин, створюючи перешкоди на шляху їх міграції, руху у пошуках їжі, притулку або репродуктивної поведінки. Явище фрагментації ареалів розглянуто з погляду не лише розділення території на окремі недоступні елементи, а і скорочення загальної площі середовища існування, зміни співвідношення площі ядра ареалу та площі його меж, де розвивається крайовий ефект. Показано, що порушення цілісності території проживання тварин порушує їх нормальну життєдіяльність і спокій через шум, освітлення та забруднення від транспорту, а також збільшує випадки зіткнення диких тварин і транспортних засобів, призводить до генетичної ізоляції, чим створює для деяких видів довготерміновий ризик вимирання. Для зменшення негативних впливів автостради проаналізовано пілотну ділянку на шосе М-03 від Полтави до Харкова в межах від 341 до 472 км, що підлягає реконструкції за проектом Світового банку. На території було виділено п'ять ділянок, де потрібно забезпечити мобільність представників дикої природи за допомогою спеціальних переходів різних типів: міст, річковий перехід, підземний перехід спільного використання, підземний перехід для малих і середніх тварин та багатоцільовий шляхопровід. Для кожного об'єкта розроблено рекомендації щодо дизайну, будівельних конструкцій і матеріалів, а також визначено цільові види тварин-користувачів та їх природоохоронний статус

The (re)location of Coworking Spaces in Ukraine During the Russian Invasion

A significant part of all firms tends to remain in the same location throughout their lives. Firm birth, death, and relocation are part of firm demography. Firm location, birth, and death are driven by several pull and push factors which also include exogenous shocks such as a foreign invasion. This paper aims to present and discuss the location of coworking spaces in Ukraine during the first year of the Russian Invasion. Several coworking spaces closed down in the Kyiv region, and others have opened in the western part of the country. The motivations driving the choice of location of three new coworking spaces in western areas are presented through interviews with the coworking spaces managers, and the role played by the coworking spaces community discusse

Generation of mesoscale cyclonic eddies in the Baltic Sea with inflow events

A sigma-coordinate ocean model, by Blumberg and Mellor (POM). is applied to study the formation processes of mesoscale cyclones observed in the Baltic Sea, following the inflow events. The initial conditions simulate a situation when the Arkona and Bomholm Basins (or Arkona Basin solely) are already filled with the inflow water of the North Sea origin. while the rest of the sea still contains the old water of pre-inflow stratification. The model runs with constant and time dependent northerly/easterly wind, changing the buoyancy forcing, grid geometry and bottom topography, display the following. Entering the East Gotland Basin from the Slupsk Furrow. the bottom intrusion of saline inflow water splits in two: one goes northeast towards the Gotland Deep and the second moves southeast towards the Gulf of Gdansk. An intensive mesoscale cyclonic eddy carrying the inflow water is generated just east of the Slupsk Furrow with the inflow pulse. A number of smaller cyclones, with boluses of the inflow water, form in the intermediate layer along the saline intrusion pathway to the Gotland Deep. A similar cyclonic eddy is generated in the Bomholm Basin with the inflow pulse from the Arkona Basin. Following Spall and Price [19}, the cyclones are expected to form by the geostrophic adjustment of high potential vorticity inflow water column to a low potential vorticity environment. Some evidence for the PV outflow/inflow hypothesis is obtained in a numerical experiment, with a virtual dam restricting water exchange between the Bomholm and Gotland Basins to the limits of the Słupsk Furrow

Experiencing disruption and transformation of communal environments: War’s influence on Ukrainian coworking spaces

In light of the Russian–Ukrainian conflict, this study explores the transformation and resilience of Ukrainian coworking spaces amid significant social disruptions, contrasting war-driven changes with those prompted by other exogenous shocks like the coronavirus disease (COVID-19) pandemic. Utilising problem-centred interviews and co-constructed autoethnographic narratives, we probe the evolving roles and organisational shifts these spaces undergo. Despite adversity, they have showcased resilience, adaptability and in most part remained functional. This research illuminates the transformative nature of community-based work environments, paving the way for the development of innovative coworking models resilient to diverse social disruptions

Microstructure measurements and estimates of entrainment in the Denmark Strait overflow plume

To examine processes controlling the entrainment of ambient water into the Denmark Strait overflow (DSO) plume/gravity current, measurements of turbulent dissipation rate were carried out by a quasi-free-falling (tethered) microstructure profiler (MSP). The MSP was specifically designed to collect data on dissipation-scale turbulence and fine thermohaline stratification in an ocean layer located as deep as 3500 m. The task was to perform microstructure measurements in the DSO plume in the lower 300 m depth interval including the bottom mixed layer and the interfacial layer below the non-turbulent ambient water. The MSP was attached to a Rosette water sampler rack equipped with a SeaBird CTDO and an RD Instruments lowered acoustic Doppler current profiler (LADCP). At a chosen depth, the MSP was remotely released from the rack to perform measurements in a quasi-free-falling mode. Using the measured vertical profiles of dissipation, the entrainment rate as well as the bottom and interfacial stresses in the DSO plume were estimated at a location 200 km downstream of the sill at depths up to 1771 m. Dissipation-derived estimates of entrainment were found to be much smaller than bulk estimates of entrainment calculated from the downstream change of the mean properties in the plume, suggesting the lateral stirring due to mesoscale eddies rather than diapycnal mixing as the main contributor to entrainment. Dissipation-derived bottom stress estimates are argued to be roughly one third the magnitude of those derived from log velocity profiles. In the interfacial layer, the Ozmidov scale calculated from turbulence dissipation rate and buoyancy frequency was found to be linearly proportional to the overturning scale extracted from conventional CTD data (the Thorpe scale), with a proportionality constant of 0.76, and a correlation coefficient of 0.77