Description: Publication date: Available online 19 January 2018 Source: Journal of Hydrology: Regional Studies Author(s): Alfonso Rivera, Lucila Candela Study region Global scale. Study focus This paper highlights the main outputs and outcomes of the Internationally Shared Aquifer Resources Management Initiative (ISARM, 2000–2015) of UNESCO on the global scale. We discuss the lessons learned, what is still relevant in ISARM, and what we consider irrelevant and why. We follow with discussion on the looming scenarios and the next steps following the awareness on transboundary aquifers (TBAs) as identified by ISARM. New insights for the region This analysis emphasizes the need for more scientific data, widespread education and training, and a more clearly defined role for governments to manage groundwater at the international level. It describes the links, approach and relevance of studies on TBAs to the UN Law of Transboundary Aquifers and on how they might fit regional strategies to assess and manage TBAs. The study discusses an important lesson learned on whether groundwater science can solve transboundary issues alone. It has become clear that science should interact with policy makers and social entities to have meaningful impacts on TBAs. Bringing together science, society, law, policy making, and harmonising information, would be important drivers and the best guidance for further assessments. ISARM can still make contributions, but it could be redesigned to support resolving TBAs issues which, in addition to science (hydrogeology), require considering social, political, economic and environmental factors. ISARM can increase its international dimension in the continents that still lag behind the assessment and shared management of TBAs, such as Asia and Africa.

Description: Forests worldwide are threatened by various environmental and anthropogenic hazards, especially tropical forests. Knowledge on the impacts of these hazards on forest structure and dynamics has been compiled in empirical studies. However, the results of these studies are often not sufficient for long-term projections and extrapolations to large spatial scales especially for unprecedented environmental conditions, which require both the identification and understanding of key underlying processes. Forest models bridge this gap by incorporating multiple ecological processes in a dynamic framework (i.e. including a realistic model structure) and addressing the complexity of forest ecosystems. Here, we describe the evolution of the individual-based and process-based forest gap model FORMIND and its application to tropical forests. At its core, the model includes physiological processes on tree level (photosynthesis, respiration, tree growth, mortality, regeneration, competition). During the past two decades, FORMIND has been used to address various scientific questions arising from different forest types by continuously extending the model structure. The model applications thus provided understanding in three main aspects: (1) the grouping of single tree species into plant functional types is a successful approach to reduce complexity in vegetation models, (2) structural realism was necessary to analyze impacts of natural and anthropogenic disturbances such as logging, fragmentation, or drought, and (3) complex ecological processes such as carbon fluxes in tropical forests – starting from the individual tree level up to the entire forest ecosystem – can be explored as a function of forest structure, species composition and disturbance regime. Overall, this review shows how the evolution of long-term modelling projects not only provides scientific understanding of forest ecosystems, but also provides benefits for ecological theory and empirical study design.

Description: Detecting changes of sediment boundaries on the seafloor is important for a better understanding of sediment dynamics and related impacts to benthic habitats. Side-scan sonars (SSS) perform more cost-effectively in shallow waters than other acoustic systems because of their larger swath widths, and the resolution of its images does not change with varying water depth. However, as they are generally towed behind the survey vessel, they tend to have lower positioning accuracy, which makes them unreliable for change detection analyses. In this study, we present a workflow that processes SSS data in a way that makes them fit for change detection analyses. To test the capacity of SSS mosaics for change detection, we used a free software called “Digital Shoreline Analysis System”, which was developed by the United States Geological Survey for ArcGIS version 10.4 onwards. The methods were applied in three areas in the Sylt Outer Reef, German Bight, North Sea. Our results showed that with appropriate processing, SSS mosaics could be used for change detection of sharp sediment boundaries. We found a common trend in the sediment distribution patterns of coarse sediments by monitoring the movement of their boundaries. The boundaries moved in northeast-southwest direction and boundary movements of less than 20 m were typically observed. The methods presented here are semi-automated, repeatable, and replicable, which has potential for wide-scale monitoring of sediment distribution patterns.

Description: Differentiating thermokarst basin sediments with respect to the involved processes and environmental conditions is an important tool to understand permafrost landscape dynamics and scenarios and future trajectories in a warming Arctic and Subarctic. Thermokarst basin deposits have complex sedimentary structures due to the variability of Yedoma source sediments, reworking during the Late Glacial to Holocene climate changes, and different stages of thermokarst history. Here we reconstruct the dynamic growth of thermokarst lakes and basins and related changes of depositional conditions preserved in sediment sequences using a combination of biogeochemical data and robust grain-size endmember analysis (rEMMA). This multi-proxy approach is used on 10 sediment cores (each 300–400 cm deep) from two key thermokarst sites to distinguish four time slices that describe the Holocene thermokarst (lake) basin evolution in Central Yakutia (CY). Biogeochemical proxies and rEMMA reveal fine-grained sedimentation with rather high lake levels and/or reducing conditions, and coarse-grained sedimentation with rather shallow lake levels and/or oxidizing (i.e. terrestrial) conditions in relation to distal and proximal depositional and post-sedimentary conditions. Statistical analysis suggests that the biogeochemical parameters are almost independent of thermokarst deposit sedimentology. Thus, the biogeochemical parameters are considered as signals of secondary (post-sedimentary) reworking. The rEMMA results are clearly reflecting grain-size variations and depositional conditions. This indicates small-scale varying depositional environments, frequently changing lake levels, and predominantly lateral expansion at the edges of rapidly growing small thermokarst lakes and basins. These small bodies finally coalesced, forming the large thermokarst basins we see today in CY. Considering previous paleoenvironmental reconstructions in Siberia, we show the initiation of thaw and subsidence during the Late Glacial to Holocene transition between about 11 and 9 cal kyrs BP, intensive and extensive thermokarst activity for the Holocene Thermal Maximum (HTM) at about 7 to 5 cal kyrs BP, severely fluctuating water levels and further lateral basin growth between 3.5 cal kyrs BP and 1.5 cal kyrs BP, and the cessation of thermokarst activity and extensive frost-induced processes (i.e. permafrost aggradation) after about 1.5 cal kyrs BP. However, gradual permafrost warming over recent decades, in addition to human impacts, has led to renewed high rates of subsidence and abrupt, rapid CY thermokarst processes.

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: The ongoing environmental changes in the Southern Ocean may cause a dramatic decrease in habitat quality. Due to its central position in the food web, Antarctic krill (Euphausia superba) is a key species of the marine Antarctic ecosystem. It is therefore crucial to understand how increasing water temperatures affect important krill life-cycle processes. Here, a long-term (August – March) laboratory acclimation experiment at different temperature scenarios (0.5 ◦C, 1.5 ◦C, 2.5 ◦C, 3.5 ◦C, 5 ◦C, 7 ◦C) was performed and the effects of elevated temperatures on whole animal parameters (O2 consumption, body length, length of the digestive gland) were analyzed. The response of krill oxygen consumption to different experimental temperatures differed between acute/short-term and long-term acclimation. After 8 months, krill oxygen consumption remained unchanged up to temperatures of 3.5 ◦C and was significantly higher at temperatures 〉 3.5 ◦C. Krill acclimated to temperatures ≥ 3.5 ◦C were significantly smaller at the end of the experiment. Limited food intake and/or conversion may have contributed to this effect, especially pronounced after the onset of the reproductive period. In addition, the seasonal growth pattern in males differed from that of females. Together, our findings indicate that warming Southern Ocean waters are likely to increase metabolic rate in krill, possibly altering the amount of energy available for other important life-cycle processes, a finding directly related to future population dynamics and fisheries management.

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.

Description: The Ocean Floor Observation and Bathymetry System (OFOBS) is an underwater survey plat-form, which is designed and developed for research in the Polar Regions by the Alfred Wegener Institute (AWI). The tailored deep tow system brought a new perspective and clarity from Arctic Ocean by its optical and acoustic sensors. During the PS101 expedition at the Karasik seamount, OFOBS provides a novel picture of megafauna’s habitats. In this study, we develop a methodology to convert the imagery dataset to micro-bathymetry in order to provide primary data for object detection and habitat mapping which will provide a better understanding of arctic benthic habitats. The methodology is based on the underwater photogrammetry workflow and two different point cloud classification methods adopted for sponge detec-tion in 3D point clouds, to facilitate habitat mapping with a focus on the central of Kara

Description: Hyperiid amphipods are predatory pelagic crustaceans that are particularly prevalent in high-latitude oceans. Many species are likely to have co-evolved with soft-bodied zooplankton groups such as salps and medusae, using them as substrate, for food, shelter or reproduction. Compared to other pelagic groups, such as fish, euphausiids and soft-bodied zooplankton, hyperiid amphipods are poorly studied especially in terms of their distribution and ecology. Hyperiids of the genus Themisto, comprising seven distinct species, are key players in temperate and cold-water pelagic ecosystems where they reach enormous levels of biomass. In these areas, they are important components of marine food webs, and they are major prey for many commercially important fish and squid stocks. In northern parts of the Southern Ocean, Themisto are so prevalent that they are considered to take on the role that Antarctic krill play further south. Nevertheless, although they are around the same size as krill, and may also occur in swarms, their feeding behaviour and mode of reproduction are completely different, hence their respective impacts on ecosystem structure differ. Themisto are major predators of meso- and macrozooplankton in several major oceanic regions covering shelves to open ocean from the polar regions to the subtropics. Based on a combination of published and unpublished occurrence data, we plot out the distributions of the seven species of Themisto. Further, we consider the different predators that rely on Themisto for a large fraction of their diet, demonstrating their major importance for higher trophic levels such as fish, seabirds and mammals. For instance, T. gaudichaudii in the Southern Ocean comprises a major part of the diets of around 80 different species of squid, fish, seabirds and marine mammals, while T. libellula in the Bering Sea and Greenland waters is a main prey item for commercially exploited fish species. We also consider the ongoing and predicted range expansions of Themisto species in light of environmental changes. In northern high latitudes, sub-Arctic Themisto species are replacing truly Arctic, ice-bound, species. In the Southern Ocean, a range expansion of T. gaudichaudii is expected as water masses warm, impacting higher trophic levels and biogeochemical cycles. We identify the many knowlegde gaps that must be filled in order to evaluate, monitor and predict the ecological shifts that will result from the changing patterns of distribution and abundance of this important pelagic group.