Description: On May 19, 2015, the German research icebreaker Polarstern began a six-week expedition to the Arctic Ocean initiated by the “ART” team, which stands for “Arctic in Rapid Transition”. The expedition PS92 (ARK XXIX/1) “TRANSSIZ” (Transitions in the Arctic Seasonal Sea Ice Zone, Fig. 1.1) conducted ecological and biogeochemical early spring process studies from the shelf to the basins of the European Arctic margin and on the Yermak Plateau, in order to link past and present sea-ice transitions in the Arctic Ocean. The cruise involved scientists from eleven countries in collaboration with research groups from divisions of the Alfred Wegener InstituteHelmholtz Centre for Polar and Marine Research together with scientists from the German BMBF-project ‘Transdrift’, as well as from the French-Canadian projects ‘GreenEdge’. Overall the vessel travelled 3,665 sm and carried out 68 stations with a total of 242 casts. Some groups also used the transit to the research area to study meridional variability of trace gases, algae species and nutrients from temperate regions of the North Atlantic and into the ice-covered Arctic Ocean by using the surface online water system. Once reaching the investigation area, the science parties conducted process studies for rate measurements of productivity, ecosystem interactions and carbon- and nitrogen cycling. By comparing data from the shelf, data from across the shelf-break into the deep basin it was possible to compare carbon export from plankton and sea ice communities as well as identifying the potential characteristics in carbon production, the fate and export, and to identify similarities and differences in ecosystem functioning along topography-, sea ice- and water mass-related gradients. The ice stations (Fig. 1.2) involved coring of a standard set of sea-ice cores for biological, physical and chemical variables as well as for trace gases and geological proxy validation. It further involved the study of sea ice properties and under-ice water and covered the study of trace and greenhouse gases, biodiversity, primary and bacterial production as well as a detailed study of the nitrogen cycle. Short-term moorings were deployed under the ice to determine the vertical carbon flux. A small Remotely Operated Vehicle (ROV) was operated under the ice to focus on spectral radiation measurements, but also to record environmental parameters (e.g. ice thickness, salinity, temperature) and video imaging of the under-ice environment. Light transmission measured with the ROV showed an increase of light penetration during the course of our expedition. The under-ice fauna and other environmental parameters were investigated by using the towed “Surface Under Ice Trawl” (SUIT). Helicopter flights were used to determine the large-scale distribution of sea-ice thickness with an EM-bird along the cruise track, which overall revealed that the average sea-ice thickness was 1.4 m, that is, comparatively thin and similar to summer vales previously observed in Fram Strait. During the sea-ice stations, parallel sampling of pelagic and benthic ecosystems and geological cores were conducted. Light spectra of hyper-spectral radiometers were used to establish the penetration depth of ultraviolet radiation into the different types of oceanic waters from the zodiac and under the ice. Water samples were taken from the water bottles of the CTD rosette to study the chemistry, biology and various geological proxies. A UVP (Underwater Video Profiler System) was deployed to provide detailed vertical profiles of particle distribution, size composition and the zooplankton community. Quantitative sampling of the mesozooplankton, and also foraminifera, which are used as paleo-proxies, were carried out by using multi-nets. For macrozooplankton and nekton, a Multiple-closing Rectangular Midwater Trawl (MRMT) was used. The distribution of macrozooplankton and pelagic fish was monitored continuously on selected transects with Polarstern’s EK60 echosounder. Benthic communities were collected by box corers and the material was further used for experimental and biogeochemical analyses of the benthic surface sediment layers, including sea ice- and paleo proxies. Benthic communities show a clear shelf to basin decrease in the oxygen demand. Overall, the communities also show a clear North South gradient in our study area. TV-Multi-corers for geological measurements were used to get undisturbed core tops of near-surface sediments (Fig. 1.3). For the geological coring, detailed bathymetric mapping and sub-bottom profiling systems (Hydrosweep and Parasound) were used to find suitable coring positions for Kastenlot and Gravity cores. Special emphasis on this cruise was taken to quantify the environmental preconditions for productivity (e.g. nutrients, stratification) which will allow us to be able to improve predictions of the potential annual primary production in a future ice-free Arctic Ocean, as well as improving reconstructions of productivity, sea ice and ocean circulation across the last 1-2 last glacial cycles. Results from the cruise will further improve the understanding of ecosystem functioning and biogeochemical cycles during the transition from spring to summer. The expedition ended on the morning of the 28th June 2015 in Longyearbyen.

Description: We compare and contrast the ecological impacts of atmospheric and oceanic circulation patterns on polar and sub-polar marine ecosystems. Circulation patterns differ strikingly between the north and south. Meridional circulation in the north provides connections between the sub-Arctic and Arctic despite the presence of encircling continental landmasses, whereas annular circulation patterns in the south tend to isolate Antarctic surface waters from those in the north. These differences influence fundamental aspects of the polar ecosystems from the amount, thickness and duration of sea ice, to the types of organisms, and the ecology of zooplankton, fish, seabirds and marine mammals. Meridional flows in both the North Pacific and the North Atlantic oceans transport heat, nutrients, and plankton northward into the Chukchi Sea, the Barents Sea, and the seas off the west coast of Greenland. In the North Atlantic, the advected heat warms the waters of the southern Barents Sea and, with advected nutrients and plankton, supports immense biomasses of fish, seabirds and marine mammals. On the Pacific side of the Arctic, cold waters flowing northward across the northern Bering and Chukchi seas during winter and spring limit the ability of boreal fish species to take advantage of high seasonal production there. Southward flow of cold Arctic waters into sub-Arctic regions of the North Atlantic occurs mainly through Fram Strait with less through the Barents Sea and the Canadian Archipelago. In the Pacific, the transport of Arctic waters and plankton southward through Bering Strait is minimal. In the Southern Ocean, the Antarctic Circumpolar Current and its associated fronts are barriers to the southward dispersal of plankton and pelagic fishes from sub-Antarctic waters, with the consequent evolution of Antarctic zooplankton and fish species largely occurring in isolation from those to the north. The Antarctic Circumpolar Current also disperses biota throughout the Southern Ocean, and as a result, the biota tends to be similar within a given broad latitudinal band. South of the Southern Boundary of the ACC, there is a large-scale divergence that brings nutrient-rich water to the surface. This divergence, along with more localized upwelling regions and deep vertical convection in winter, generates elevated nutrient levels throughout the Antarctic at the end of austral winter. However, such elevated nutrient levels do not support elevated phytoplankton productivity through the entire Southern Ocean, as iron concentrations are rapidly removed to limiting levels by spring blooms in deep waters. However, coastal regions, with the upward mixing of iron, maintain greatly enhanced rates of production, especially in coastal polynyas. In these coastal areas, elevated primary production supports large biomasses of zooplankton, fish, seabirds, and mammals. As climate warming affects these advective processes and their heat content, there will likely be major changes in the distribution and abundance of polar biota, in particular the biota dependent on sea ice.

Description: Publication date: Available online 1 September 2017 Source: The Egyptian Journal of Remote Sensing and Space Science Author(s): H.A. Bharath, M.C. Chandan, S. Vinay, T.V. Ramachandra Metropolitan cities in India are emerging as major economic hubs with an unprecedented land use changes and decline of environmental resources. Globalisation and consequent relaxations of Indian markets to global players has given impetus to rapid urbanisation process. Urbanisation being irreversible and rapid coupled with fast growth of population during the last century, contributed to serious ecological and environmental consequences. This necessitates monitoring and advance visualisation of spatial patterns of landscape dynamics for evolving appropriate management strategies towards sustainable development approaches. This study visualises the growth of Indian mega cities Delhi, Mumbai, Pune, Chennai and Coimbatore, through Cellular Automata Markov model considering the influence of agent(s) of urban growth through soft computing techniques. CA Markov model is considered to be one of most effective algorithm to visualise the growth of urban spatial structures. Prediction of growth using agent based modelling considering the spatial patterns of urbanisation during the past four decades has provided insights to the urban dynamics. The industrial, infrastructural, socio-economic factors significantly influence the urban growth compared to the biophysical factors. Visualisation of urban growth suggest agents driven growth in the cities and its surroundings with large land use transformations in urban corridors and upcoming Industrial and ear marked developmental zones. Integrating local agents of urban growth help in identifying specific regions of intense growth, likely challenges and provide opportunities for evolving appropriate management strategies towards sustainable cities during the 21st century.