characterizing groundwater lake interactions and its impact on lake water quality summary geochemical tracers were used to investigate groundwater lake interactions and to map nutrient concentrations within georgetown lake a 1219 ha lake situated at 1960 m above sea level between two mountain ranges in western montana radon 222 was used to identify locations and relative amounts of groundwater inflow to the lake and nutrients were sampled to investigate the role of groundwater on nutrient dynamics occurring within the lake sampling primarily took place during late winter and early spring when the lake was frozen stratified and relatively anoxic and all lake samples were collected near the bottom of the lake radon concentrations in the lake varied spatially from less than 3 5 194 0 pci l radon results show that groundwater enters the lake through fractured paleozoic karst limestone situated near a major thrust fault no groundwater flows were noted on the western side of the lake which is underlain by west dipping precambrian metasedimentary rocks the western two thirds of the lake is anoxic near the bottom of the water column with h2s and nh 4 concentrations as high as 1 99 mg l and 4 0 mg l respectively along the eastern side of the lake h2s was absent and nh 4 was generally low suggesting that groundwater inflows improve water quality pore water diffusion samplers show that there is an internal source of nh 4 h2s and po 4 3 to the lake originating from decay of organic carbon in the lake sediments

estimating groundwater exchange with lakes 1 the stable isotope mass balance method groundwater inflow and outflow contributions to the hydrologic budget of lakes can be determined using a stable isotope 18o 16o mass balance method the stable isotope method provides a way of integrating the spatial and temporal complexities of the flow field around a lake thereby offering an appealing alternative to the traditional time and labor intensive methods using seepage meters and an extensive piezometer network in this paper the method is applied to a lake in northern wisconsin demonstrating that it can be successfully applied to lakes in the upper midwest where thousands of similar lakes exist inflow and outflow rates calculated for the wisconsin lake using the isotope mass balance method are 29 and 54 cm yr respectively which compare well to estimates derived independently using a three dimensional groundwater flow and solute transport model of 20 and 50 cm yr such a favorable comparison lends confidence to the use of the stable isotope method to estimate groundwater exchange with lakes in addition utilization of stable isotopes in studies of groundwater lake systems lends insight into mixing processes occurring in the unsaturated zone and in the aquifer surrounding the lake and verifies assumed flow paths based on head measurements in piezometers

balancing rare earth element distributions in the northwestern mediterranean sea abstract elemental concentrations of rare earth elements ree and isotopic compositions of neodymium end have been measured in three water column profiles in the north western mediterranean sea clear enrichments of ree are observed when comparing to adjacent atlantic waters suggesting ree inputs along the circulation in this area for the first time relative proportions of external sources including submarine groundwater discharges sgd have been quantified for the studied area atmospheric deposition is estimated to be the most important external source for all the ree with an average contribution of 44 followed by diffusion from porewaters which provide a 30 dissolved riverine fluxes account for 11 sgd for 10 and dissolution of remobilized surface sediments the remaining 6 mass balances accounting for seawater transport and identified external sources have been delineated for the three main water masses modified atlantic waters levantine intermediate waters and western mediterranean deep waters they show that the balances of ree in this area are dominated by seawater mass mixing superimposed on this hydrography ree vertical profiles are affected by external sources and biogeochemical cycling dissolved ree are correctly balanced in deep waters whereas substantial missing fluxes are identified in the surface and intermediate water masses additional net lree outputs and hree inputs are required in the surface waters while net output fluxes for all the ree are missing at intermediate waters the most likely process suggested here is an active reversible scavenging consistent with a stronger adsorption of lree compared to hree in the particular case of the redox sensitive cerium the most plausible mechanism to explain the net output missing fluxes is ce 3 removal by particle scavenging via oxidation to insoluble ce 4 estimated ce oxidation rates of 0 33 d 1 in surface waters agree well with previously published values exchange fluxes derived from the isotopic nd mass balance indicate higher nd scavenging in surface compared to intermediate waters

submarine groundwater discharge driven nitrogen fluxes to long island sound ny terrestrial vs marine sources abstract bottom waters in smithtown bay long island sound ny are subject to hypoxic conditions every summer despite limited nutrient inputs from waste water and riverine sources while modeling estimates of groundwater inputs are thought to be insignificant terrestrial and marine fluxes of submarine groundwater discharge sgd were quantified to smithtown bay using mass balances of 222 rn 224 ra 226 ra and 228 ra during the spring and summer of 2014 2015 in order to track this seasonal transition period intertidal pore waters from a coastal bluff terrestrial sgd and from a barrier beach marine sgd displayed substantial differences in n concentrations and sources traced using a multi isotope approach 222 rn ra 15 n no 3 18 o no 3 no 3 in terrestrial sgd did not display any seasonality and was derived from residential septic systems and fertilizer marine sgd n concentrations varied month to month because of mixing between oxic seawater and hypoxic saline pore waters n concentrations were greatest during the summer when no 3 was derived from the remineralization of organic matter short lived 222 rn and 224 ra sgd fluxes were used to determine remineralized n loads along tidal recirculation flow paths while long lived 228 ra was used to trace inputs of anthropogenic n in terrestrial sgd 228 ra derived terrestrial n load estimates were between 20 and 55 lower than 224 ra derived estimates excluding spring 2014 228 ra may be a more appropriate tracer of terrestrial sgd n loads terrestrial sgd no 3 derived from 228 ra to smithtown bay varied from 1 40 12 8 10 6 mol n y 1 with comparable marine sgd no 3 fluxes of 1 70 6 79 10 6 mol n y 1 derived from 222 rn and 224 ra remineralized n loads were greater during the summer compared with spring and these may be an important driver toward the onset of seasonal hypoxic conditions in smithtown bay and western long island sound seawater recirculation through the coastal aquifer can rival the n load from terrestrial sgd from a heavily polluted aquifer

numerical modeling of tidal effects on groundwater dynamics in a multi layered estuary aquifer system using equivalent tidal loading boundary condition case study in zhanjiang china this paper presents a numerical modeling study of tidal effects on groundwater dynamics of a multi layered estuary aquifer system in this study to generalize the tidal loading effects on the confined aquifer we used equivalent tidal loading boundary condition based on existing analytical solutions for the confined aquifer in a three dimensional numerical model and then good simulated result was obtained using the numerical model the tide induced groundwater level and confined groundwater discharge dynamics were discussed and the following conclusions were obtained the combined action of sea tide and river tide can enhance the tidal response of groundwater level in the aquifer system especially for the confined groundwater the river tidal effect is more significant in the areas away from coastline although the confined aquifer is separated by a layer of clay from the ocean because of the tidal loading effects the confined groundwater discharge also changes periodically displaying a negative correlation with the tide level fluctuations like the unconfined groundwater discharge using linear functions that express the relationship between the mean confined groundwater flux and sea tide level the confined groundwater flux through the tidal loading boundaries can be approximately estimated when the sea tide level is higher than 4 4 m there would be a risk of seawater intrusion into the confined aquifer in the study area this case study is useful for numerical studying of tidal effects on groundwater resource dynamics in a coastal multi layered estuary aquifer system

quaternary glaciations in the southern ocean sector 0 long 180 long abstract isolated islands in the southern ocean east of 0 longitude are all of volcanic origin as some were active both volcanically and tectonically during the quaternary glacial features may be masked and confused by lava flows and faulting the location of the islands close to the antarctic convergence is potentially important for studying fluctuations in its position northward migration cools the islands and causes glacier expansion intercalation of glacial sediments and lava flows on marion kerguelan and heard islands provides some evidence of glacier fluctuations during the mid late quaternary but much of the data are equivocal the most detailed dated quaternary record is from marion island where the oldest glaciation stage 8 had five stadials the penultimate glaciation stage 6 had three stadials and the last glaciation had ended by 12 ka bp glacier expansion is closely related to northward migration of the antarctic convergence when lower temperature converts the high rainfall into snowfall

simulation of dispersion in layered coastal aquifer systems abstract a density dependent solute transport formulation is used to examine ground water flow in layered coastal aquifers the numerical experiments indicate that although the transition zone may be thought of as an impermeable sharp interface with freshwater flow parallel to the transition zone in homogeneous aquifers this is not the case for layered systems freshwater can discharge through the transition zone in the confining units further for the best simulation of layered coastal aquifer systems either a flow direction dependent dispersion formulation is required or the dispersivities must change spatially to reflect the tight thin confining unit

investigation of submarine groundwater discharge to tidal rivers evidence for regional and local scale seepage fluxes of submarine groundwater discharge sgd were investigated into two tidal rivers on the north and south shore of long island ny during july 2015 ground based handheld thermal infrared tir imagery combined with direct push point piezometer sampling documented spatially heterogeneous small scale intertidal seepage zones pore waters were relatively fresh and enriched in nitrogen n within these small scale seeps pore waters sampled just 20 cm away outside the boundary of the ground based tir located seepage zone were more saline and lower in n these ground based tir identified seeps geochemically represented the terrestrial fresh groundwater endmember whereas n in pore waters sampled outside of the tir identified seeps was derived from the remineralization of organic matter introduced into the sediment by tidal seawater infiltration a 222rn radon 222 time series was used to quantify fresh sgd associated n fluxes using the n endmembers sampled from the ground based tir pore water profiles n fluxes were up scaled to groundwater seepage zones identified from high resolution airborne tir imagery using the two dimensional size of the airborne tir surface water anomalies relative to the n flux from the time series sampling location results suggest that the n load from the north shore tidal river to long island sound is underrepresented by at least 1 6 3 6 whereas the n load from sgd to a south shore tidal river may be up to 9 higher than previous estimates these results demonstrate the importance of sgd in supplying nutrients to the lower reaches of tidal rivers and suggest that n loads in other tidal river environments may be underestimated if sgd is not accounted for

localisation and temporal variability of groundwater discharge into the dead sea using thermal satellite data the semi arid region of the dead sea heavily relies on groundwater resources this dependence is exacerbated by both population growth and agricultural activities and demands a sustainable groundwater management yet information on groundwater discharge as one main component for a sustainable management varies significantly in this area moreover discharge locations volume and temporal variability are still only partly known a multi temporal thermal satellite approach is applied to localise and semi quantitatively assess groundwater discharge along the entire coastline the authors use 100 landsat etm band 6 2 data spanning the years between 2000 and 2011 in the first instance raw data are transformed to sea surface temperature sst to account for groundwater intermittency and to provide a seasonally independent data set t maximum sst range per pixel within biennial periods is calculated subsequently groundwater affected areas gaa are characterised by t 10 c this allows the exact identification of 37 discharge locations clusters along the entire dead sea coast which spatially correspond to available in situ discharge observations tracking the gaa extents as a direct indicator of groundwater discharge volume over time reveals 1 a temporal variability correspondence between gaa extents and recharge amounts 2 the reported rigid ratios of discharge volumes between different spring areas not to be valid for all years considering the total discharge 3 a certain variability in discharge locations as a consequence of the dead sea level drop and finally 4 the assumed flushing effect of old dead sea brines from the sedimentary body to have occurred at least during the two series of 2000 2001 and 2010 2011

geologic controls of submarine groundwater discharge application of remote sensing to north lebanon typical of mediterranean countries the lebanese shoreline is well known for its littoral and offshore groundwater discharges the so called submarine springs the tectonic framework of the terrain explains its interruption by dense geologic structures i e fracturing faulting karstic routes as well as acute dips of rock strata seaward all of these structures serve as hydrologic agents transporting groundwater to the sea the study aims to locate these groundwater discharges and to interpret their geologic controls on land for this purpose two major lines of approach were followed the first is an airborne thermal infrared tir survey using radiometers to identify thermal anomalies thereby determining the exact location of submarine groundwater discharges sgds the second line of approach is the analysis of satellite images landsat 7etm to delineate the geologic features that govern the mechanism of water flow thereby determining their sources on land twenty seven major sgds were identified 10 of these being offshore springs the others littoral springs the springs show a large variety of discharge configurations and extents mainly parallel or perpendicular to the shoreline or rounded three major structural controls were identified to contribute to the transport of groundwater to the sea these are karstic galleries faults and tilted rock strata their contributions being 48 37 and 15 respectively the sgds associated with linear passageways i e karstic galleries and faults are connected with land aquifer formations several kilometers away from the shoreline moreover the presence of impervious rock formations at many localities along the coastline results in a confined hydrologic system promoting the flow of sgds into the sea

regional scale assessment of submarine groundwater discharge in ireland combining medium resolution satellite imagery and geochemical tracing techniques abstract this paper sets the foundation for the use of freely available landsat enhanced thematic mapper etm thermal infrared tir imagery in a regional scale assessment of submarine groundwater discharge sgd to coastal waters a comprehensive tiered three step approach is proposed as the most effective and affordable means to determine the spatial extent and scale of sgd from coastal aquifers to the coastal margin as the preliminary step sea surface temperature sst values derived from landsat etm tir are used to successfully detect plumes of colder water eventually associated with sgd in close proximity to the shoreline subsequently potential sites of sgd are linked to geological features on land acting as possible sources by combining within a geographical information system gis mapped temperature anomalies with ancillary on shore spatial datasets describing bedrock geology including aquifer fault lines finally nearshore surveys mapping the activity of 222 rn radon and salinity are carried out to verify the presence of sgd and provide a qualitative assessment of fresh groundwater inputs to the coastal zone practical application of the complete approach in the context of coastal zone management is illustrated through a case study of the republic of ireland as part of this study over 30 previously unidentified links between aquifers on land and the sea are shown along the irish coast hence illustrating the tight coupling between coastal waters and groundwater inputs at an unprecedented spatial scale the study demonstrates the potential of the combined applications of remote sensing methods and geochemical tracing techniques for a cost effective regional scale assessment of groundwater discharge to coastal waters

quantification of submarine intertidal groundwater discharge and nutrient loading from a lowland karst catchment summary submarine groundwater discharge sgd is now recognised to be a process of significant importance to coastal systems and is of increasing interest within oceanographic and hydrologic research communities however due to the inherent difficulty of measuring sgd accurately its quantification at any particular location is a relatively slow process often involving multiple labour intensive methods in this paper the sgd occurring at kinvara bay the outlet of a lowland karst catchment in western ireland is estimated using a hydrological model of the karst aquifer and then further verified by means of a relatively simple salinity survey discharge at kinvara predominantly occurs via two springs kinvara west kw which serves as the outlet of a major primarily allogenically fed karst conduit network and kinvara east ke which discharges water from more diffuse autogenic sources discharge from these springs occurs intertidally and as such their flow rates cannot be measured using traditional methods using the hydrological model flow rates from kw were seen to vary between 5 and 16 m3 s with a mean value of 8 7 m3 s through hydrochemical analysis this estimated discharge was found to be supplemented by an additional 14 18 via sources not accounted for by the model mean discharge at ke was also estimated as approximately 2 m3 s thus the total mean discharge from both kinvara springs was determined to be 11 9 12 3 m3 s overall the range of discharge was found to be lower than previous studies have estimated as these studies had no means of quantifying attenuation within the conduit network combining this discharge with nutrient concentrations from the springs the nutrient loading from the springs into the bay was estimated as 1230 kg day n and 24 3 kg day p this research illustrates the benefits of a numerical modelling approach to the quantification of sgd when used in the appropriate hydrological scenario

holocene glacial history of antarctica and the sub antarctic islands abstract a history of holocene glaciation in the antarctic and sub antarctic affords insight into questions concerning present and future ice sheet and mountain glacier behavior and global climate and sea level change existing records permit broad correlation of holocene ice fluctuations within the region in several areas ice extent was less than at present in mid holocene time an important exception to this is the west antarctic ice sheet which has undergone continued recession throughout the holocene probably in response to internal dynamics the first neoglacial ice advances occurred at 5 0 ka although some sites e g western ross sea lack firm evidence for glacial expansion at that time glaciers in all areas underwent renewed growth in the past millennium and most have subsequently undergone recession in the past 50 years ranging from near catastrophic in parts of the antarctic peninsula to minor in the western ross sea region and sections of east antarctica this magnitude difference likely reflects the much greater warming that is taking place in the antarctic peninsula region today as compared to east antarctica

statistical fits for auroral oval boundaries during the substorm sequence we present statistical fits for the auroral oval boundaries during the substorm sequence the fits describe some substorm phase dependent changes in the boundary locations which have not been taken into account in the models presented earlier we have located both the diffuse and discrete oval boundary crossings using particle precipitation data from defense meteorological satellite program satellites and categorized the locations according to the substorm phase and the level of magnetic activity determined from the ae index our analysis and data set are especially favorable for studying the oval boundary locations during growth and recovery phases during expansion phase the dynamic poleward boundary of the oval is very difficult to model statistically and in addition the critical postmidnight data points making the auroral bulge more visible were missing from our data set in our results the phase dependent changes are largest during the recovery phase and they strengthen with increasing magnetic activity up to about 5 in the morning sector during the recovery phase the ovals are clearly wider than in the evening and midnight sectors and during other substorm phases this effect cannot be seen in the traditional oval models because they have not been designed for use during the recovery phase when magnetic activity is low but the morning sector of the oval is still very wide

importance of geochemical transformations in determining submarine groundwater discharge derived trace metal and nutrient fluxes abstract seasonal spring and summer 2002 concentrations of dissolved 3 po 4 si and doc were determined in groundwater samples from 5 wells aligned along a 30 m shore normal transect in west neck bay long island ny results show that significant systematic changes in groundwater trace metal and nutrient composition occur along the flowpath from land to sea while conservative mixing between west neck bay water and the groundwaters explains the behavior of si and doc non conservative inputs for co and ni were observed concentration increases of 10 and 2 fold respectively and removal of po 4 and no 3 decreases to about half along the transport pathway groundwater associated chemical fluxes from the aquifer to the embayment calculated for constituents not exhibiting conservative behavior can vary by orders of magnitude depending on sampling location and season e g co 3 4 10 2 8 2 10 3 mol d 1 using measured values from different wells as being representative of the true groundwater endmember chemical composition also results in calculation of very different fluxes e g cu 6 3 10 3 mol d 1 inland freshwater well vs 2 1 10 5 mol d 1 seaward well s 17 ppt this study suggests that seasonal variability and chemical changes occurring within the subterranean estuary must be taken into account when determining the groundwater flux of dissolved trace metals and nutrients to the coastal ocean

evaluation of 224 ra as a tracer for submarine groundwater discharge in long island sound ny abstract the approach to quantify submarine groundwater discharge using ra isotopes generally involves developing a ra mass balance in an estuary bay or lagoon in this work we present a 224ra mass balance used to evaluate the importance of the submarine groundwater discharge sgd in long island sound ny us the third most important estuary in us located between long island and connecticut that is usually affected by summertime hypoxia in the western basin three surveys were conducted between april 2009 and august 2010 where 25 water stations were sampled for ra isotopes oxygen and mn stations were oriented along 4 transects one axial extending from the western to the eastern sound and three longitudinal transects in the western central and eastern sound the inventory of 224ra in the water column in summer was circa 2 times greater than in winter suggesting an increased 224ra flux to the sound in summer a mass balance for 224ra was constructed considering tidal exchange inputs from rivers desorption from resuspended particles diffusive fluxes including bioirrigation from bottom sediments and radioactive decay in the water column fluxes of 224ra from bottom sediments were measured by incubating cores under oxic conditions in a continuous flow mode such that the overlying water was circulated through a mn oxide fiber to maintain a constant activity of 224ra fluxes from muddy sediments comprising 67 of the sound bottom ranged from 127 to 312 dpm m 2 d 1 and were 60 dpm m 2 d 1 in sandy sediments 33 of the sound incubations under hypoxic conditions showed variable fluxes depending on reduction and mobilization of mn the 224ra mass balance shows a net input of ra to the sound of 106 50 1012 dpm y 1 in spring and 244 112 1012 dpm y 1 in the summer that is attributed to sgd elevated 224ra values were observed near shore and in the pore fluids of the coarse beach sands along the long island and connecticut coasts suggesting that sgd driven by tidal recirculation through the beach face is a major source of 224ra to the sound seasonal variation in this source seems unlikely and the calculated 224ra sgd fluxes for spring and summer overlap within the uncertainties nevertheless we conclude that variations in the 224ra water column inventories could be produced by seasonal changes in bioirrigation and or redox cycling of mn as well as sediment resuspension and desorption of 224ra from resuspended particles and that our mass balance underestimates these terms particularly in the summer 224ra fluxes from sediments in estuaries especially those with significant areas of muddy sediments and seasonal hypoxia are important and should be well constrained in future uses of this isotope as a tracer for sgd

aerial infrared imaging reveals large nutrient rich groundwater inputs to the ocean 1 regional high resolution 0 1 c 0 5 m low altitude thermal infrared imagery tir reveals the exact input locations and fine scale mixing structure of massive cool groundwaters that discharge into the coastal zone as both diffuse flows and as 30 large point sourced nutrient rich plumes along the dry western half of the large volcanic island of hawaii these inputs are the sole source of new nutrient delivery to coastal waters in this oligotrophic setting water column profiling and nutrient sampling show that the plumes are cold buoyant nutrient rich brackish mixtures of groundwater and seawater by way of example we illustrate in detail one of the larger plumes which discharges ca 12 000 m3 d 1 ca 8 600 m3 d 1 freshwater rates comparable in volume to high flux groundwater outputs in better known tropical karst terrains we further show how nutrient mixing trends may be integrated into tir sea surface temperatures to produce surface water nutrient maps of regional extent

source and distribution of dissolved radium in the bega river estuary southeastern australia abstract measurements of the activities of the four naturally occurring radium isotopes in the surface water and porewater of an estuary have yielded information on the release of radium from sediments and on the extent of surface water porewater interaction in the estuary under low flow conditions the non conservative behaviour of dissolved radium in the estuary is almost entirely due to the flux of radium from estuarine bed sediments radium accumulates in bottom sediment porewater and is then mixed with estuarine surface water probably as a result of tidal action it is shown experimentally that the enrichment of the short lived isotopes 224ra and 223ra relative to 226ra in estuarine porewater can be explained by the repeated leaching of radium from bottom sediments by saline water and the rapid regeneration of the short lived isotope activity from their sediment bound parent nuclides the leaching of radium from bottom sediments is apparently occurring on a time scale which is long weeks months compared with the 224ra and 223ra half lives indicating that the amount of ion exchangeable radium adsorbed to the sediments is large compared with the amount dissolved in porewater by applying a simple 2 d steady state multi box model 224ra and 223ra surface water and porewater concentrations have been used to estimate the daily flux of porewater crossing the sediment water interface in the bega estuary this flux is found to be about 15 of the estuary volume

application of galdit index to assess the intrinsic vulnerability to seawater intrusion of coastal granular aquifers groundwater within coastal aquifers is considered a very sensitive natural resource since its quantity and quality is threatened by anthropogenic activities as well as global and climate changes the major environmental hazard with respect to coastal aquifers is the phenomenon of seawater intrusion and is more pronounced in the mediterranean basin in the light of smart management of such hydrogeological systems galdit index was introduced in the form of a numerical ranking system that aims to assess the vulnerability of such aquifers to seawater intrusion this paper provides an application of galdit vulnerability index for a typical mediterranean alluvial aquifer under variable hydrogeological conditions in different research periods 1992 and 2004 the results proved the significance of the piezometric conditions of the aquifer with respect to its vulnerability to seawater intrusion

distribution of auroral surges in the evening sector over the past dacades a large statistical data base has been gathered consisting of both ground based magnetometer and all sky camera records from which researchers have inferred the distribution of substorm expansive phase events across the nighttime sector almost without exception the activity distribution has been based on single station data acquired over periods of years however to truly establish the occurrence frequency of substorm expansive phase events it is necessary to view the entire nighttime sector instantaneously in the light of evidence which shows that more than one expansive phase disturbance can be in progress across the broad expanse of the evening sector in this paper the authors study the distribution of regions of localized auroral luminosity in the poleward portion of the evening sectorauroral oval using images in the ultraviolet portion of the auroral spectrum acquired by the viking satellite over 9 months in 1986 they find that auroral surge activity peaks in the hour before local magnetic midnight with the probability of detecting a surge steadily decreasing to 10 of the probability of finding a surge in the hour prior to midnight as one moves westward towards 1 900 mlt they show that their conclusion is not dependent onmore the threshold chosen for surge identification over a reasonable portion of the intensity range covered by the viking imager they further show that for the interval of several months near sunspot minimum in 1986 there is better than a 90 chance that no surge will be detected in a 1 hour range of magnetic local time if one were to sample that segment of the auroral oval at any arbitrary time less

evidence in favour of an extensive ice cover on sub antarctic kerguelen island during the last glacial abstract arguments to date have suggested that during the last glacial wurm wisconsin weichselian sub antarctic kerguelen island did not experience an extensive ice cover and that the fjords and glacial valleys are products of earlier events recent observations of striation orientations travel directions of erratics cirque altitudes and evidence for isostatic uplift suggest that there in fact may have been extensive ice cover the equilibrium line altitude e l a reconstructed for the cirque glacier stage agrees well with that for sub antarctic marion island situated to the west a possible explanation for the lack of glacial deposits and landforms over much of the island is suggested

the development of the substorm expansive phase the eye of the substorm the explosive onset and development of a clearly defined auroral substorm has been analysed using data from the ultraviolet imager aboard the viking satellite these data permit the evolution of the substorm to be traced with a time resolution as high as 40 seconds the envelope of the disturbed region the eye expands both poleward and azimuthally to the east and west reaching an azimuthal extent of almost six hours of magnetic local time after about 15 minutes the poleward expansion involves irregular poleward motion accompanying intensifications within the eye with the maximum poleward displacement being at the meridian of the center of the eye within the eye discrete regions of enhanced luminosity develop with a tendency for each newly disturbed region to be to the west of the previous ones it is however observed that a newly excited region can be to the east of the pre existing activated region each new intensification is accompanied by a brief further poleward expansion of the high latitude edge of the eye each region of enhanced luminosity within the eye remains relatively stationary and fluctuates in intensity over its lifetime we identify these regions of enhanced luminosity with westward traveling surges as defined from ground observations in the earlier literature our uv imager data demonstrate that these surges do not necessarily propagate although the overall envelope of the substorm disturbed region expands both eastward and westward during the lifetime of the event

glacier extent in sub antarctic kerguelen archipelago from mis 3 period evidence from 36cl dating documenting sub antarctic glacier variations during the local last glacial maximum is of major interest to better understand their sensitivity to atmospheric and oceanic temperature changes in conjunction with antarctic ice sheet changes however data are sparse because evidence of earlier glacier extents is for most sub antarctic islands located offshore making their observation complex here we present cosmogenic 36cl surface exposure ages obtained from five sites at kerguelen to document the glacial history the 36cl ages from roche moutonnee surfaces erratics and boulders collected on moraines span from 41 9 4 4 ka to 14 3 1 1 ka ice began to retreat on the eastern part of the main island before 41 4 4 4 ka slow deglaciation occurred from 41 to 29 ka there is no evidence of advances between 29 ka and the antarctic cold reversal acr period 14 5 12 9 ka period during the acr however the bontemps and possibly belvedere moraines were formed by the advance of a cook ice cap outlet glacier and a local glacier on the presque ile jeanne d arc respectively this glacier evolution differs partly from that of glaciers in new zealand and in patagonia these asynchronous glacier changes in the sub antarctic region are however in agreement with sea surface temperature changes recorded around antarctica which suggest differences in the climate evolution of the indo pacific and atlantic sectors of antarctica

use of electrical imaging and distributed temperature sensing methods to characterize surface water groundwater exchange regulating uranium transport at the hanford 300 area washington 1 we explored the use of continuous waterborne electrical imaging cwei in conjunction with fiber optic distributed temperature sensor fo dts monitoring to improve the conceptual model for uranium transport within the columbia river corridor at the hanford 300 area washington we first inverted resistivity and induced polarization cwei data sets for distributions of electrical resistivity and polarizability from which the spatial complexity of the primary hydrogeologic units was reconstructed variations in the depth to the interface between the overlying coarse grained high permeability hanford formation and the underlying finer grained less permeable ringold formation an important contact that limits vertical migration of contaminants were resolved along 3 km of the river corridor centered on the 300 area polarizability images were translated into lithologic images using established relationships between polarizability and surface area normalized to pore volume spor the fo dts data recorded along 1 5 km of cable with a 1 m spatial resolution and 5 min sampling interval revealed subreaches showing 1 temperature anomalies relatively warm in winter and cool in summer and 2 a strong correlation between temperature and river stage negative in winter and positive in summer both indicative of reaches of enhanced surface water groundwater exchange the fo dts data sets confirm the hydrologic significance of the variability identified in the cwei and reveal a pattern of highly focused exchange concentrated at springs where the hanford formation is thickest our findings illustrate how the combination of cwei and fo dts technologies can characterize surface water groundwater exchange in a complex coupled river aquifer system

impact of lateral transport on organic proxies in the southern ocean lateral transport of fine grained organic carbon particles can complicate the interpretation of paleoclimate records based on organic proxies here we investigated the effect of lateral transport on newly developed temperature and soil organic matter proxies tex86 and bit index respectively in core md88 769 recovered from the south east indian ridge our results show that tex86 and bit records in comparison to diatom and foraminifera records were representative for more local climate changes while alkenones and n alkanes originated from distant areas by oceanic and atmospheric transport respectively this suggests that tex86 and bit paleoclimate records are primarily influenced by local conditions and less subjected to long distance lateral transport than other organic proxies in the southern ocean

estimating groundwater discharge into the northeastern gulf of mexico using radon 222 abstract submarine groundwater discharge sgd may provide important chemical constituents to the ocean but the dispersed nature of this process makes locating and quantifying its input extremely difficult since groundwater contains 3 4 orders of magnitude greater radon than seawater 222rn may be a useful tracer of this process if all other sources of radon to bottom waters can be evaluated we report development of a sgd tracing tool based on radon inventories in a coastal area of the northeastern gulf of mexico we evaluated factors that influence the concentration of radon in the water column i e production decay horizontal transport and loss across the pycnocline using a linked benthic exchange horizontal transport model total 222rn benthic fluxes 2420 dpm m 2 day 1 measured with in situ chambers are of the magnitude required to support measured sub pycnocline 222rn inventories while estimates of molecular diffusion show that this input is relatively small 230 dpm m 2 day 1 using this model approach together with measurements of the radon inventory we estimated a regional subsurface fluid flow ranging from 180 to 710 m3 sec 1 into the 620 km2 study area this discharge equivalent to an upward advective velocity of approximately 2 10 cm day 1 dispersed over this entire study area is equivalent to approximately 20 first magnitude springs

40ar 39ar geochronology of flood basalts from the kerguelen archipelago southern indian ocean implications for cenozoic eruption rates of the kerguelen plume the 6500 km2 kerguelen archipelago formed on the northern kerguelen plateau nkp 4 105 km2 which is a shallow submarine plateau belonging to the kerguelen large igneous province in the southern indian ocean flood basalts make up 85 of the archipelago and are interpreted as the most recent volcanism 40 ma from the kerguelen hotspot which has erupted basalt for the last 115 million years based on 40ar 39ar incremental heating of acid leached groundmass separates we report isochron ages ranging from 29 26 0 87 ma to 24 53 0 29 ma for 15 basalts from five stratigraphic sections from diverse regions of the archipelago the oldest dated basalt from the archipelago 29 ma is much younger than the 40 ma age of conjunction between the hotspot and the southeast indian ridge basalt eruption seems to have ceased shortly after 24 ma although small volume highly evolved lavas and plutons continued to form in the archipelago the basalt age data suggest an average lava accumulation rate of 1 6 0 9 km my during the oligocene the archipelago s volumetric eruption rate 0 009 km3 yr is lower than estimates made for the cretaceous kerguelen plateau 1 7 km3 yr and the ninetyeast ridge hotspot track 0 18 km3 yr suggesting that the late cenozoic extrusive activity of the kerguelen plume is waning cenozoic volcanism attributed to the kerguelen plume occurs over a diffuse area with quaternary eruptions at heard and mcdonald islands and within the kerguelen archipelago the decreasing eruption rate and areally diffuse volcanism may be explained by the thick lithosphere of the cretaceous kerguelen plateau overriding and insulating the plume however if the undated nkp which underlies the archipelago formed during the cenozoic then the crustal production rate of the plume from 40 ma to the present 0 25 km3 yr would be similar to the crustal production rate 0 23 km3 my previously estimated for the formation of the ninetyeast ridge 82 38 ma

the last termination in the south indian ocean a unique terrestrial record from kerguelen islands 49 s situated within the southern hemisphere westerly belt the awareness of the significance of the southern ocean in the earth s climate system has become increasingly obvious the deglacial atmospheric co2 rise during warming periods in antarctica has been attributed to co2 ventilation from the deep ocean caused by enhanced upwelling around the antarctic divergence it has been hypothesized that more intense southern hemisphere westerly winds aligned with the antarctic circumpolar current due to a southward shift of the wind belt from its last glacial maximum equator ward position are the main drivers reconstructions of past changes in atmospheric circulation in the southern hemisphere are still scarce and the overall picture is patchy with sometimes contradictory results for obvious reasons most terrestrial records originate from southern south america and new zealand here we present a terrestrial record from the indian sector of the southern ocean from kerguelen islands located at 49 s a peat record is investigated using a multi proxy approach pollen and plant macrofossils magnetic susceptibility xrf analyses biogenic silica content rock eval6 analysis and humification degree peat accumulation starts at about 16 000 cal yr bp with relatively warm and dry conditions the most prominent change in our proxy data occurs at 13 600 cal yr bp when peat ponds were established on the peat surface resulting in lacustrine type deposits as a result of very high humidity and with proxies implying very windy conditions within chronological uncertainties this onset coincides with the onset of the so called oceanic cold reversal based on the deuterium excess data in the epica dome c ice core record kerguelen islands are located in the moisture source area of dome c and a change in atmospheric circulation at that time could explain both records around 12 900 cal yr bp at the end of the antarctic cold reversal pond lake sediments give way to more peaty deposits with proxies suggesting slightly drier less windy and probably warmer conditions kerguelen islands became less influenced by the southern hemisphere westerly winds and these conditions were amplified during the early holocene climate optimum as found in antarctic ice core records

using the radium quartet to quantify submarine groundwater discharge and porewater exchange abstract the specific ingrowth rates of different radium isotopes make them valuable tracers to distinguish processes occurring at different temporal scales here we demonstrate the use of the radium quartet 223ra 224ra 226ra and 228ra to differentiate flows of submarine groundwater discharge and porewater exchange to a coastal embayment alfacs bay nw mediterranean sea based on the assumption that these processes occur on different time scales in order to evaluate the seasonal dynamics of groundwater and porewater inputs to the bay we conducted three seasonal samplings at alfacs bay during which samples for ra isotopes were collected from bay waters groundwater springs porewaters and irrigation channels activities of short lived ra isotopes in the bay showed a strong seasonality e g average 224ra activities in summer 32 dpm 100 l 1 up to 4 times higher than in winter 8 dpm 100 l 1 in contrast the activities of the long lived ra isotopes were fairly constant throughout the year e g activities of 226ra were 16 and 14 dpm 100 l 1 in summer and winter respectively the relatively short exposure to sediments of recirculation fluxes resulted in porewaters significantly enriched in short lived ra isotopes relative to the long lived ones e g 224ra 1100 1300 dpm 100 l 1 226ra 17 99 dpm 100 l 1 whereas coastal groundwaters were enriched in all the ra isotopes e g 224ra 120 150 dpm 100 l 1 226ra 200 400 dpm 100 l 1 the distinct signatures of different sources allowed us to construct seasonal ra mass balances to estimate both groundwater discharge which ranges from 40 60 103 m3 d 1 in summer to 310 200 103 m3 d 1 in winter and porewater exchange fluxes ranging from 1200 120 103 m3 d 1 in summer to 270 40 103 m3 d 1 in winter whereas the seasonal variability of groundwater inputs is likely governed by the terrestrial hydraulic gradient a qualitative evaluation of the drivers of porewater exchange suggested that the strong seasonality of the seawater recirculation inputs is likely mediated by seasonal cycles on the activity of benthic infauna ra isotopes are thus valuable tracers to differentiate fluxes of both submarine groundwater discharge and porewater exchange allowing a more accurate evaluation of the fluxes of freshwater and solutes to coastal ecosystems as well as their implications for coastal biogeochemical cycles

submarine groundwater discharge revealed by aerial thermal infrared imagery a case study on jeju island korea submarine groundwater discharge sgd is a global phenomenon that carries large volumes of groundwater and dissolved chemical species such as nutrient metals and organic compounds to coastal zones we report the influence of sgd on the coastal waters of jeju island korea using high resolution aerial thermal infrared tir mapping techniques and field investigations an aircraft based system was implemented using a cost effective tir camera for aerial tir mapping ground based calibrations and system integration with gps imu global positioning system inertial measurement unit were performed for the aerial systems the aerial surveys showed distinct low temperature signatures of sgd along the coasts of jeju island revealing large groundwater inputs from the coastal aquifers to the ocean multiple aerial surveys over a range of seasons and tidal stages revealed that sgd rates dynamically affect the sea surface temperature sst of the coastal zone the in situ measurements supported that sgd has a substantial influence on the coastal water chemistry as well as sst our observations highlight the extent to which aerial based tir mapping can serve as a powerful tool for studying sgd and other coastal processes copyright 2016 john wiley sons ltd

groundwater discharge into an estuary using spatially distributed radon time series and radium isotopes summary quantifying groundwater discharge remains a challenge due to its large temporal and spatial variability here we quantify groundwater discharge into a small estuary using radon 222rn and radium isotopes 223ra and 224ra high temporal resolution 30 min time steps radon observations at 4 time series stations were used to determine where groundwater discharge is prevalent in the estuary and to reduce mass balance model uncertainties a three endmember mixing model was developed based on short lived radium isotopes sampled at a single location to separate the shallow saline and deep fresh sources of the discharging groundwater the results show that using multiple 222rn time series stations decreased the overall uncertainty of groundwater discharge estimates from about 41 to 23 the radon derived groundwater flux was 56 13 and 35 12 cm d 1 in wet and dry conditions respectively the spatially distributed stations detected a well defined small area located four kilometers upstream from the mouth of the estuary as a groundwater discharging hotspot estimates based on a 223ra and 224ra mass balance resulted in groundwater discharge estimates of 65 18 and 84 48 cm d 1 in the wet and 18 5 and 20 6 cm d 1 in the dry the mixing model revealed contrasting results for deep vs fresh groundwater contribution in wet and dry conditions in wet conditions deep fresh groundwater discharging into the estuary contributed 65 compared to the shallow saline groundwater 35 while during dry conditions a larger contribution 80 was related to shallow groundwater a comprehensive spatial and temporal sampling strategy can produce groundwater discharge estimates with lower uncertainty and provides additional insight on where groundwater enters surface waters

late quaternary glacial history of the south orkney plateau antarctica abstract piston cores from the south orkney plateau penetrated overcompacted diamictons in water depths of up to 250 m detailed textural and petrological analyses of these diamictons indicate that they are basal tills seismic records from the plateau show a widespread surface of glacial erosion and provide additional evidence of an ice cap grounded to a depth of 250 m piston cores from the slope of the plateau penetrated diatomaceous muds resting directly on poorly sorted muds with very little to no biogenic material the ice rafted debris in these glacial marine sediments is composed almost exclusively of material derived from the south orkney islands this implies deposition beneath an ice shelf as opposed to iceberg rafting in contrast diatomaceous muds contain relatively abundant exotic iceberg rafted material and reflect a glacial maritime setting similar to that of today the sharp contact separating diatomaceous surface sediments from basal tills and sub ice shelf deposits indicates that the ice cap and ice shelf retreated from the plateau rapidly radiocarbon dates for diatomaceous muds from a glacial trough on the plateau indicate that the ice cap and ice shelf retreated from the plateau prior to 6000 to 7000 years ago the homogeneity of surficial diatomaceous sediments suggests that sea ice conditions over the plateau have not changed radically since that time

coastal sea surface temperature variability from landsat infrared data abstract a time series of 23 landsat thematic mapper tm band 6 thermal infrared images over the period 1986 1996 is used to quantify variability of sea surface temperature sst along the central coast of maine a morphologically complex region of bays estuaries and islands an iterative regression scheme using coregistered temporally coincident daily composites of advanced very high resolution radiometer avhrr pathfinder sst data is used to scale the tm digital numbers in each scene to sst approximating an atmospheric correction this approach provides temporally concurrent match ups even for landsat scenes more than 10 years old and over 1000 data points to most regressions analysis of the tm scenes by year day delivers temporal resolution sufficient for insight into overall seasonal pattern and allows identification of recurring seasonal features within the study area the dominant seasonal patterns is a cross shelf sst gradient of coldest water nearshore in winter which reverses sign in summer and disappears in spring and fall differences in summer sst are evident between four adjacent bays attributable to differences in residual circulation freshwater input and flushing recurrent frontal zones evident in summer are identified and compare well to available but noncoincident in situ hydrographic data

evaluating the source and seasonality of submarine groundwater discharge using a radon 222 pore water transport model article i nfo pore water radon 222 rn distributions from indian river lagoon florida are characterized by three zones a lower zone where pore water 222 rn and sediment bound radium 226 ra are in equilibrium and concentration gradients are vertical a middle zone where 222 rn is in excess of sediment bound 226 ra and concentration gradients are concave downward and an upper zone where 222 rn concentration gradients are

karst channelled intertidal submarine groundwater discharge sgd conditions the form of the rock pool sessile assemblage abstract freshwater submarine groundwater discharge sgd frequently occurs in areas of karst coastline where karst aquifers are hydraulically connected to the sea though up to 25 of the world s coastline is karst little work has been done to determine the ecological impacts of karst channelled freshwater sgd reported herein are the effects of karst channelled freshwater sgd on the rock pool sessile assemblage in the locale of olhos de agua on the south portuguese coast two quadrat surveys were conducted in eight intertidal rock pools which ranged in freshwater sgd content from 0 to 57 3 salinity and nitrogen no3 and no2 concentrations were measured in the eight surveyed rock pools as well as a further three rock pools on the same plateau three inland groundwater boreholes and the adjacent coastal marine environment there was a strong negative correlation between salinity used as a proxy for freshwater sgd and nitrogen concentration r2 0 98 p

stream functions and equivalent freshwater heads for modeling regional flow of variable density groundwater 1 review of theory and verification steady state flow of variable density groundwater is simulated using equivalent freshwater heads and stream functions on the basis of the work by de josselin de jong 1960 1969 fluids with different fluid densities are replaced by one hypothetical fluid and singularities are introduced along interfaces where the actual fluids change densities the basic flow equation describing variable density flow written in terms of equivalent freshwater head is used to derive the corresponding stream function equation and associated boundary conditions neumann boundary conditions for the stream function equation can be determined from gradients of equivalent freshwater heads along the boundary stream functions provide a direct representation of the groundwater flow pattern and flow rates where fluid densities vary in space in comparison equivalent freshwater heads and fluid densities describe the two driving forces hydraulic gradient and buoyancy force but head gradients do not necessarily describe the flow direction of variable density groundwater in isotropic media comparison of the finite element formulations indicates that potential errors in the centroid consistent velocity calculation based on the stream function solution can be expected to be smaller than those in the velocity calculation based on the head solution for cross sectional flow models because discretization in the vertical direction is typically finer than in the horizontal direction

using a thermal tracer to estimate overland and rill flow velocities flow velocity is a basic hydraulic property of surface flows and its precise calculation is necessary for process based hydrological models such as soil erosion and rill development models as well as for modelling sediment and solute transport by runoff this study presents a technique based on infrared thermography to visualize very shallow flows and allow a quantitative measurement of overland flow and rill flow velocities laboratory experiments were conducted to compare the traditional dye tracer technique with this new thermal tracer technique by injecting a combined tracer heated dye into shallow flowing surface water the leading edge tracer velocities estimated by means of infrared video and by the usual real imaging video were compared the results show that thermal tracers can be used to estimate both overland and rill flow velocities since measurements are similar to those resulting from using dye tracers the main advantage of using thermography was the higher visibility of the leading edge of the injected tracer compared with the real image videos copyright 2013 john wiley sons ltd

tracing anthropogenically driven groundwater discharge into a coastal lagoon from southern brazil summary we investigated the distribution of naturally occurring geochemical tracers 222 rn 223 ra 224 ra 226 ra ch 4 18 o and 2 h in the water column and adjacent groundwater of mangueira lagoon as proxies of groundwater discharge mangueira lagoon is a large 90 km long shallow 4 5 m deep fresh and non tidal coastal lagoon in southern brazil surrounded by extensively irrigated rice plantations and numerous irrigation canals we hypothesized that the annual intense irrigation for rice agriculture creates extreme conditions that seasonally change groundwater discharge patterns in the adjacent lagoon we further supposed that dredging of irrigation canals alters groundwater fluxes while the activities of 222 rn in shallow groundwater were 2 3 orders of magnitude higher than in surface water ch 4 and radium isotopes were only 1 order of magnitude higher therefore 222 rn appears to be the preferred groundwater tracer in this system radon concentrations and conductivities were dramatically higher near the pump house of rice irrigation canals consistent with a groundwater source modeling of radon inventories accounting for total inputs groundwater advection diffusion from sediments and decay of 226 ra and losses atmospheric evasion horizontal mixing and decay indicated that groundwater advection rates in the irrigation canals 25 cm d are over 2 orders of magnitude higher than along the shoreline 0 1 cm d nearly 75 of the total area of the canals is found in the southern half of the lagoon where groundwater inputs seem to be higher as also indicated by methane and stable isotope trends in spite of the relatively small area of the canals we estimate that they contribute nearly 70 of the total 57 000 m 3 d groundwater input into the entire mangueira lagoon we suggest that the dredging of these canals cut through aquitards which previously restricted upward advection from the underlying permeable strata the irrigation channels may therefore represent an important but previously overlooked source of nutrients and other dissolved chemicals derived from agricultural practices into the lagoon

combining radon short lived radium isotopes and hydrodynamic modeling to assess submarine groundwater discharge from an anthropized semiarid watershed to a mediterranean lagoon mar menor se spain summary in highly anthropized watersheds surface water tributaries may carry unexpected high quantities of radon and radium to coastal lagoons investigating submarine groundwater discharge sgd with radionuclide tracers is therefore a complex task in order to quantify sgd and decipher the influence of the different water sources we combined a radon 222 rn and short lived radium 223 ra 224 ra survey with the hydrodynamic modeling of a lagoon we applied it to the mar menor lagoon se spain where surface water tributaries and undocumented emissaries carry water from groundwater drainage and brines from groundwater desalinization we identified the areas of influence of the plume of radionuclides from the river located major areas of sgd and proposed a location for two submarine emissaries porewater i e interstitial water from underlying sediments was found to be the most representative sgd end member compared to continental groundwater collected from piezometers mass balances in winter and summer seasons provided yearly sgd fluxes of water of 0 4 2 2 10 8 m 3 y 222 rn 4 4 19 0 10 8 m 3 y 224 ra and 1 3 10 8 m 3 y 223 ra measured in winter only tidal pumping was identified as a main driver for recirculated saline groundwater while fresh submarine groundwater discharge from the aquifer ranged between 2 and 23 of total sgd

using the radium quartet for evaluating groundwater input and water exchange in salt marshes the fluxes of 226ra half life 1600 years and 228ra half life 5 7 years from the north inlet salt marsh to the sea are much larger than can be supported by decay of their th parents in the surface marsh sediments these fluxes are sustained almost entirely by groundwater flow through the marsh an average groundwater flow of approximately 10 cm3 cm 2 day 1 is indicated if the groundwater activities we have measured are representative the fluxes of 223ra half life 11 4 day and 224ra half life 3 6 day are factors of 22 and ten more than those expected from the flux of 226ra groundwater also sustains most of the flux of the short lived isotopes the measured ra activity ratio pattern in the marsh creeks matches the groundwater signature but is distinct from the pattern of the parent thorium isotopes in the sediment we present a model to explain the anomalous distribution pattern of these isotopes despite their large throughput the inventories of desorbable 226ra and 228ra in the top 15 cm sediment layer are very low nevertheless the activities of 226ra and 228ra in the porewaters are large indicating a low distribution coefficient 10 for radium and a short retention time 10 days in the surface sediment layer we surmise that groundwater flow may be a significant source of radium isotopes in the waters of shallow estuaries and coastal margins this source must be recognized while considering mass balance of any tracer be it radium nutrients other metals or 18o

terrestrial and submarine evidence for the extent and timing of the last glacial maximum and the onset of deglaciation on the maritime antarctic and sub antarctic islands this paper is the maritime and sub antarctic contribution to the scientific committee for antarctic research scar past antarctic ice sheet dynamics pais community antarctic ice sheet reconstruction the overarching aim for all sectors of antarctica was to reconstruct the last glacial maximum lgm ice sheet extent and thickness and map the subsequent deglaciation in a series of 5000 year time slices however our review of the literature found surprisingly few high quality chronological constraints on changing glacier extents on these timescales in the maritime and sub antarctic sector therefore in this paper we focus on an assessment of the terrestrial and offshore evidence for the lgm ice extent establishing minimum ages for the onset of deglaciation and separating evidence of deglaciation from lgm limits from those associated with later holocene glacier fluctuations evidence included geomorphological descriptions of glacial landscapes radiocarbon dated basal peat and lake sediment deposits cosmogenic isotope ages of glacial features and molecular biological data we propose a classification of the glacial history of the maritime and sub antarctic islands based on this assembled evidence these include type i islands which accumulated little or no lgm ice type ii islands with a limited lgm ice extent but evidence of extensive earlier continental shelf glaciations type iii seamounts and volcanoes unlikely to have accumulated significant lgm ice cover type iv islands on shallow shelves with both terrestrial and submarine evidence of lgm and or earlier ice expansion type v islands north of the antarctic polar front with terrestrial evidence of lgm ice expansion and type vi islands with no data finally we review the climatological and geomorphological settings that separate the glaciological history of the islands within this classification scheme

a reevaluation of submarine groundwater discharge along the southeastern coast of north america 1 new data of fluxes of radium isotopes and concentrations of radium in coastal groundwater enable an estimation of fluxes of submarine groundwater discharge sgd to a large section of the south atlantic bight sab the new fluxes are considerably greater than sgd fluxes to this region estimated earlier the annual average total sgd fluxes which represent a range of salinity are 3 times greater than the river fluxes the highest fluxes of radium and sgd occur in the summer off the coast of georgia when scaled per kilometer of shoreline the sgd flux is the same for the coastlines of onslow bay nc 140 km a section of the south atlantic bight from onslow bay nc to cresent beach florida united states 600 km and the entire atlantic ocean 75 000 km the fact that each independent estimate is based on different methods and assumptions gives confidence to the results these sgd fluxes are not restricted to the shoreline but occur throughout the continental shelf they are important for supplying not only radium but also nutrients carbon metals and freshwater to these coastal waters citation moore w s 2010 a reevaluation of submarine groundwater discharge along the southeastern coast of north america global biogeochem cycles 24 gb4005 doi 10 1029 2009gb003747

hydrologic forcing of submarine groundwater discharge insight from a seasonal study of radium isotopes in a groundwater dominated salt marsh estuary a seasonal study of radium derived submarine groundwater discharge sgd and associated nitrogen fluxes was carried out in a salt marsh estuary between 2001 and 2003 pamet river estuary massachusetts twelvehour time series of salinity and radium at the estuary inlet were used to determine the relative importance of fresh versus saline sgd respectively the distinct radium 228ra 226ra isotopic signature of marsh peat pore water and aquifer derived brackish groundwater was used to further partition the ra derived sgd estimate of these three groundwater sources only the marsh derived groundwater was constant across time the ratio of brackish to fresh sgd was inversely correlated with water table elevation in the aquifer suggesting that ra derived sgd was enhanced during dry periods the various sgd fluxes were responsible for an average annual dissolved inorganic nitrogen din input of between 1 7 mol m 2 yr 1 and 7 1 mol m 2 yr 1 and a soluble reactive phosphate srp flux of 0 13 0 54 mol m 2 yr 1 approximately 30 of the sgd derived din and srp flux is exported to coastal waters cape cod bay whereas 70 is retained by the salt marsh ecosystem

groundwater lake interactions i accuracy of seepage meter estimates of lake seepage abstract the use of seepage meters to identify nearshore seepage patterns and to quantify seepage in lakes was evaluated with a monte carlo simulation model the model simulated seepage flux as would be derived from seepage meter measurements along a transect extending from the shore of a hypothetical lake to 40 or 100m offshore along the transect simulated seepage velocities decreased exponentially with distance from shore according to patterns measured at narrow lake alta and lake sallie mn to determine statistical parameters needed in the model seepage flux was measured in situ with closely spaced seepage meters at four different sites in narrow lake seepage velocities within a small area of lakebed were log normally distributed and the variance was positively correlated with mean seepage flux the modeling indicated that the most sensitive parameter affecting the accuracy of seepage meter estimates of seepage patterns and average seepage flux along the transect was the variability in the spatial distribution of seepage flux within a small area of lakebed there was little improvement in the accuracy of estimates of seepage patterns or transect flux when more than ten seepage meters were simulated along the transect when the transect was sampled more than twice or when seepage meters along the transect were simulated to follow a stratified rather than a systematic design

dynamic response of a rocky cliff under the sea wave pulse a study along the adriatic coast of polignano apulia italy the dynamic behavior of a rocky cliff under severe sea waves has been analyzed in the location of polignano facing on the adriatic coast of apulia southern italy in this area the classical and at the same time complex problem of the stability of a cliff in calcareous rocks is burdened by the presence on the top of the cliff of the ancient town to analyze the behavior of the cliff under the impulsive transfer of energy generated by the sea waves two types of measures were carried out on the rocky mass 1 ambient noise and 2 strong motion records the first type of measures which may be executed in a short time with a high spatial density has provided a recognition of the intrinsic and anisotropic dynamic behavior of the coastal cliff the accelerometric records carried out during heavy storms in december 2009 and january 2010 allowed to evaluate the energy transfer from waves to cliff in terms of maximum values and temporal and directional distribution to facilitate a correct interpretation of the measures also a geomechanical characterization of the rocky mass has been carried out through the rock mass rating system bieniawski the geomechanics classification in rock engineering applications proceedings of the 4th isrm cong montreux pp 51 58 1979 bieniawski engineering rock mass classifications wiley new york p 251 1989 and the markland s test a useful technique for estimating the stability of rock slopes when the rigid wedge sliding type of failure is expected pp 10 1972 the first allowed to classify the rocky masses in terms of quality the second one to individuate the potential failure mechanisms of the cliff

quantification of groundwater discharge into lakes using radon 222 as naturally occurring tracer a case study was carried out with the aim to practically test whether estimates of groundwater discharge rates into dredging lakes can be made via an uncomplicated and straightforward technique using radon 222 as naturally occurring groundwater tracer lake ammelshainer see a dredging seepage lake approximately 25 km east of leipzig germany was chosen as the investigation site in order to evaluate changes in the spatial and temporal radon 222 patterns in the lake during different stages of stratification sampling campaigns were conducted in april 2007 well mixed stage and in may 2007 thermal stratification stage groundwater flow estimates were made using a radon mass balance approach accounting for all radon fluxes into and out of the lake and assuming steady state conditions with respect to these radon fluxes once all positive and negative radon fluxes related to the lake water volume were determined groundwater discharge was estimated by using the advective radon input and the radon activity concentration of the pore water as key parameters the results showed that in case of a lake with a size and shape of lake ammelshainer see 530 000m2 reasonable groundwater discharge estimates can be made by collection and analyzing just a few water samples and a few samples from the sediment layer

assessing groundwater surface water connectivity using radon and major ions prior to coal seam gas development richmond river catchment australia abstract coal seam gas csg or coal bed methane mining is rapidly growing with poorly understood impacts on groundwater and surface water systems here we use chemical tracers to investigate groundwater surface water connectivity in an australian river system richmond river catchment new south wales prior to csg extraction but after 50 exploratory csg wells were drilled we performed four surveys of 29 interconnected creek and river sites over contrasting hydrological conditions radon was used to determine if a surface water segment was gaining groundwater radon observations over four seasons revealed that 28 out of 77 surface water segments were clearly gaining groundwater 5 were possibly gaining groundwater and 44 were undetermined this is equivalent to gaining segments in 333 km 39 of surface water from the 864 km being investigated high spatial and temporal variability in groundwater gaining segments was found na cl ratios were used to determine the fraction of groundwater in surface water overall the groundwater contribution in surface waters was 14 24 higher in post flood conditions than during the other three surveys of baseflow and moderate flow conditions the results serve as a regional baseline assessment of river water chemistry and groundwater surface water connectivity prior to the planned development of csg fields our geochemical tracer approach allows for a quick qualitative assessment of groundwater surface water connectivity in poorly gauged river systems and can define priority locations where groundwater extraction for csg mining should be carefully managed

scientific results from the viking ultraviolet imager an introduction the ultraviolet imager on the viking spacecraft provides global images of aurora in both night and day hemispheres at rates of up to three per minute first results summarized in this and a set of eight companion papers reveal new aspects of the patterns and dynamics of the aurora including eastward as well as westward expanding substorm intensifications but very little evidence of bulk westward motion of auroral surges rapid poleward and equatorward expansions during some substorms resulting in the formation of an intense eye shaped bulge containing diffuse aurora and north south aligned arc segments substorm like intensifications at the point where transpolar arcs join the nightside oval rapid small scale auroral brightenings or hot spots over a wide range of local times and very rapid changes in auroral forms in the noon sector

assessing the role of submarine groundwater discharge as a source of sr to the mediterranean sea abstract submarine groundwater discharge sgd has been identified as an important source of sr to the ocean and the sgd driven sr flux to the global ocean has been recently re evaluated beck et al 2013 however the uncertainty of this value is still high because of the uncertainties related to the determination of sgd flow rates and the paucity of 87 sr 86 sr data in sgd end members as carbonates have high sr concentrations and are subjected to intense heightened weathering they might significantly influence the sgd input of sr to the ocean here we present data on sr concentrations and 87 sr 86 sr ratios in three carbonate dominated sites of the western area of the mediterranean sea a semi enclosed basin characterized by abundant coastal carbonates the 87 sr 86 sr ratios in groundwater were lower compared to modern seawater 0 70916 as expected for areas dominated by carbonate lithologies concentrations of sr and 87 sr 86 sr ratios in groundwater showed conservative mixing in the studied subterranean estuaries by using sgd flow rates reported in the literature for the study areas a flow weighted fresh sgd end member characterized by a sr concentration of 27 30 m and a 87 sr 86 sr ratio of 0 707834 0 708020 was calculated for the eastern coast of the iberian peninsula integrating these sr data with literature data i e values of sr concentration and 87 sr 86 sr ratio from other lithologies as well as sgd flow rates we also calculated the fresh sgd driven sr flux to the entire mediterranean sea obtaining a value of 0 34 0 83 10 9 mol y 1 with a 87 sr 86 sr of 0 7081 0 7086 thus for the entire mediterranean basin sgd is globally a source of sr less radiogenic compared to seawater the sgd sr flux to the mediterranean sea represents 5 6 of the sgd sr flux to the global ocean and the mediterranean sgd end member has higher sr concentration 5 12 m than the global sgd end member 2 9 m this confirms the significant role of carbonate lithologies on sgd driven sr fluxes to seawater the fresh sgd driven sr flux to the mediterranean sea is about 20 50 of the riverine sr input and significantly higher than the input through atmospheric dust deposition therefore sgd should be considered as an important continental source of sr to the basin

societal use of fresh submarine groundwater discharge an overlooked water resource abstract terrestrial groundwater discharging directly into the sea fresh submarine groundwater discharge fresh sgd is increasingly recognized as nutrient and pollutant pathway from land to coastal oceans however its active use by coastal populations and its role for coastal societies is nearly entirely neglected here we present examples from a variety of places and from all available sources around the world to highlight that fresh submarine groundwater discharge is widely valued as a water resource for drinking hygiene agriculture fishing tourism culture or ship navigation in peru fresh sgd is used for drinking on tahiti for bathing in greece for irrigation in bali for blessing and already alexander von humboldt noted the danger for smaller vessels from a submarine spring off cuba but at which manatees gathered and were hunted by fishermen these are just a few of the presented examples which document the complex value fresh submarine groundwater discharge has for coastal communities because global change will strongly affect this water resource we should assess and understand that value before the phenomenon will disappear at many locations due to terrestrial groundwater extraction or sea level increase

sub antartic glacier extensions in the kerguelen region 49 s indian ocean over the past 24 000 years constrained by 36cl moraine dating similar to many other regions in the world glaciers in the southern sub polar regions are currently retreating in the kerguelen islands 49 s 69 e the mass balance of the cook ice cap cic the largest ice cap in this region experienced dramatic shrinking between 1960 and 2013 with retreat rates among the highest in the world this observation needs to be evaluated in a long term context however data on the past glacier extents are sparse in the sub antartic regions to investigate the deglaciation pattern since the last glacial maximum lgm period we present the first 13 cosmogenic 36cl surface exposure ages from four sites in the kerguelen islands the 36cl ages from erratic and moraine boulders span form 24 4 2 7 ka to 0 3 0 1 ka we combined these ages with existing glacio marine radiocarbon ages and bathymetric data to document the temporal and spatial changes of the island s glacial history ice began to retreat on the main island before 24 4 2 7 ka until around the time of the antartic cold reversal acr period 14 5 12 9ka during which the bontemps moraine was formed by the advance of a cic outlet glacier deglaciation continued during the holocene probably until 3ka with evidence of minor advances during the last millennium the chronology is in pace with major changes in 18o in a recent west antarctica ice core record showing thet kerguelen islands glciers are particularly sensitive and relevant to document climate change in the southern polar regions

seasonal changes in groundwater input to a well mixed estuary estimated using radium isotopes and implications for coastal nutrient budgets 226ra half life 1 600 yr and 228ra half life 5 75 yr were used as tracers to determine seasonal changes in groundwater input to the pettaquamscutt estuary from june 1999 to june 2000 ra isotopes were observed to be in excess of activities due to input from streams rhode island sound water and particle desorption the source of excess 226ra and 228ra within the estuary is attributed to groundwater transport of ra derived from the weathering of bedrock within the pettaquamscutt watershed short lived 224ra half life 3 66 d was used to calculate an average residence time of the estuary of 8 4 d box models used to constrain seasonal changes in groundwater input to the estuary indicate highest groundwater input in the summer 6 4 20 l m 2 d 1 and lowest values in the winter 2 1 6 9 l m 2 d 1 these ra derived groundwater fluxes are similar to rates of aquifer recharge over the annual cycle using these ra derived groundwater fluxes the input of inorganic nitrogen and phosphorus from groundwater to the pettaquamscutt was estimated at 61 180 mmol m 2 yr 1 and 4 4 13 mmol m 2 yr 1 respectively

statistical description of the bulge type auroral substorm in the far ultraviolet 1 using global auroral images at ultraviolet wavelengths during 116 substorms we have obtained quantitative measures of key features of the bulge aurora and oval aurora their temporal variations their locations rates and characteristics of gross expansion and decay and the variability of these parameters the expansion period identified solely from images varied primarily from 10 to 40 minutes with an average of 30 9 minutes to avoid mixing expansion data with recovery data we normalized the time of each substorm to one unit from onset to maximum expansion the average onset location was 22 6 magnetic local time mlt and 66 8 invariant latitude ilat in good agreement with previous analyses we found that the bulge aurora rapidly expanded out of the onset location approximately equally to the west surge and to the east so that the average center of the bulge remained close to the onset mlt this is also the case for average location of the maximum expansion in latitude of the bulge thus the bulge is offset about 1 1 2 hours west of midnight by half the expansion period the bulge has usually expanded poleward sufficiently to reveal a brightened portion of the original auroral oval this brightening expands less than 1 hour mlt to the west but rapidly to the east farther than the east end of the bulge thus the two auroras are offset in mlt the bulge expansion is fastest initially but slows for the second half of the expansion period the ends of the bulge continue a small expansion poleward during early recovery when the center of the bulge slowly retreats the large spreads of substorm expansion times the onset locations and in the locations in mlt and ilat of the key features of these auroras argue strongly for the need to normalize the time of expansion and location of key features of the substorm for any kind of superposed epoch analysis to be meaningful

carbon dioxide dynamics driven by groundwater discharge in a coastal floodplain creek summary dissolved carbon dioxide co 2 may be highly enriched in groundwater however the contribution of groundwater discharge as a source of co 2 to rivers estuaries and coastal waters is poorly understood we performed high resolution measurements of radon 222 rn a natural groundwater tracer and the partial pressure of co 2 p co 2 in a highly modified tidal creek and estuary north creek richmond river new south wales australia to assess whether co 2 in surface waters was driven by groundwater discharge a spatial survey revealed increasing 222 rn activities up to 17 3 dpm l 1 and p co 2 up to 11 151 atm in the upstream direction the enrichment occurred in a drained coastal acid sulphate soil wetland upstream of a mangrove forest time series experiments 24 h were performed at two stations upstream and downstream of the p co 2 enrichment area upstream measurements demonstrated a significant correlation between p co 2 and 222 rn while downstream values resulted in a significant inverse relationship between p co 2 and dissolved oxygen apparently as a result of respiration in nearby mangroves measurements taken 2 days after a 245 mm precipitation event revealed the highest recorded 222 rn activities up to 86 1 dpm l 1 and high p co 2 up to 11 217 atm showing a strong groundwater influence after flooding these observations imply that groundwater discharge drove co 2 dynamics at the upstream station while multiple complex processes drove co 2 at the downstream station a 222 rn mass balance model demonstrated that groundwater discharge accounted for about 76 of surface water in this floodplain creek the co 2 evasion rates 799 225 mmol m 2 d 1 were driven primarily by currents rather than wind groundwater derived co 2 fluxes into the creek averaged 1622 mmol m 2 d 1 a value twice as high as atmospheric co 2 evasion and consistent with carbon uptake within the creek and downstream exports these results demonstrate that groundwater seepage was a major factor driving co 2 evasion to the atmosphere from the creek groundwater discharge should be accounted for in co 2 budgets in coastal systems

using radon 222 and radium 226 isotopes to deduce the functioning of a coastal aquifer adjacent to a hypersaline lake in nw iran abstract this study aims to assess the hydrogeochemistry of coastal groundwater the occurrence of 222rn and 226ra and their isotopic response to salinity and associated chemical compositions of groundwater in the coastal urmia aquifer ua at the western side of urmia lake ul the results of the pca show that 87 3 of groundwater chemistry changes are controlled by six principal components the interaction between groundwater and coastal igneous and metamorphic rocks in eastern areas next to the ul results in complex hydrogeochemical conditions than western areas based on correlation of u and salinity some coastal samples display conservative and the others non conservative behaviors differed from most previous studies 226ra and 222rn concentrations in coastal groundwater samples of ua do not show a good correlation with salinity given 10 of groundwater 222rn is originated from host rocks the radon concentrations recorded in the coastal groundwater samples are relatively in range that can effectively be supplied by the local rocks 5 49 bq l results of different chemical and isotopic parameters in this area indicate that there is no direct connection between fresh groundwater and ul saltwater this is because that the hard and thick salty layer in the lakebed acts as an impermeable barrier to prevent the underground hydraulic connection results show that removing the salty layer of ul as an option to progress in rehabilitation program of this lake may result in more hydraulic connection between the lake and groundwater resources in some areas

the importance of groundwater discharge to the methane budgets of nearshore and continental shelf waters of the northeastern gulf of mexico methane concentrations in groundwater wells sinkholes and springs averaged 61 9 mu m while concentrations in nearshore and continental shelf waters within the study area averaged 62 7 nm and 27 5 nm respectively we tested the hypothesis that the three orders of magnitude difference between groundwater and seawater concentration would make ch sub 4 an indicator of submarine groundwater discharge to surficial waters methane budgets for nearshore and continental shelf water columns were consistent with the hypothesis that groundwater seepage or seawater recirculation through the seabed is the dominant source of ch sub 4 relative to benthic diffusive flux riverine flux and in situ water column production seepage recirculation appears to account for approximately 83 99 of the total ch sub 4 input into the water column within the study area utilizing measured porewater ch sub 4 concentrations the calculated amounts of seepage required to support the observed benthic fluxes were comparable to seepage rates measured in the field nearshore seepage meter transacts showed a strong and direct correlation between the integrated quantity of groundwater seepage along a shoreline and the inventory of ch sub 4 in those waters our study further showed a similar correlation between sup 222 rn another potential groundwater tracer andmore ch sub 4 in offshore waters supporting the hypothesis of a common benthic source for these constituents 67 refs 10 figs 2 tabs less

quantifying groundwater discharge from different sources into a mediterranean wetland by using 222rn and ra isotopes summary groundwater discharge constitutes the main water inflow of many coastal wetlands despite the potential of ra isotopes and 222rn as tracers of groundwater discharge the use of these radionuclides to quantify the groundwater inflow in coastal wetlands has been only scarcely addressed in the literature the main goal of this study is to evaluate the use of 222rn and ra isotopes to estimate the contribution of distinct groundwater sources into a mediterranean coastal wetland the peniscola marsh castello spain the peniscola marsh is a small shallow wetland nourished by groundwater coming from four different flowpaths i a deep flow from the regional carbonate aquifer of el maestrat ii a shallow flow and iii an intermediate flow both from the irta range and the detritic vinaros peniscola aquifer and iv seawater intrusion data on 226ra 222rn and salinity obtained in summer 2007 revealed that the deep groundwater contribution was 15 of the total water inflow whereas the shallow and intermediate flow paths represented 32 and 48 respectively seawater accounted only for the remaining 5 inputs to the wetland ra isotopes also allowed estimating the marsh water age in 1 2 days both the groundwater contributions derived from 222rn measurements and the ra derived marsh water age agreed well with the direct measurements obtained using propeller flow meters evidencing the effectiveness of the used methods an interannual comparison between the estimated groundwater inflow and the precipitation revealed that shallow groundwater flows respond to local precipitation whereas the deep groundwater flow from the carbonate aquifer is dominated by a constant baseflow

calcium concentrations in wetland groundwater in relation to water sources and soil conditions in the recharge area schol p p and wassen m j 1993 calcium concentrations ill wetland groundwater in rehtlion to water sou rces a nd soil conditions in tile recharge area j hydrol 141 197 217 over the past several decades vegetation eommunities i lowland wetlands in western europe have changed species rich love productivity i e low primary bion ss production communities characteristic of rich fens fens characterized by alinc ophilous specms have declined and are being replaced by vegetation communities characterislic of high productivity rich fens poor fens fens characterized by nmbrophilous specicsi and bogs high concentrations of calcium ie groundwater are generally believed to bc an important controlling factor on the vegetation of rich fens management for the protection of low productivity rich fells therefore generally aims at conscrvution of calcareous groundwater conditions in the rool zone of lowland wetlands this paper relates the occurrence of calcium rich groundwaler in t wland e ellands of the central nether ands to water sources and soil conditions in the groundwater recharge area the chemical compostlion of the following groundwater types is compared groundwater recharged at a sandy ridge adjacent to tile wclhmd area ridge walcr groundwater recharged by precipitation witnn the wetland peat water groundwater recharged by surface water in the wetland objective hydrological criteria arc used to classify gr mndwater analyses according to recharge area oxygen 18 proved an essentia 1 criterion for the distinclion between genetic groundwater types it is therefore recommended to make oxyt en 18 analysis standard proccdm e ill geo lydrological wetland research calcium concentrations are generall not suitable as tracers of different types of recharge areas all groundwater types contain calcium in contrast to what is generally assnrned lowest concenlralions arc observed in ridge waler iligher calcium concentrations are found in gronndw ler recharged in wctllnlds especially ill intihratcd surface water nutrient concenlralinns in both ridge a d peal water are imv while those in iniilttaled surface water are signilicant y higher the nlain conclusion for nature clmservalion is thai calcium rich and me otrophie cot ri ions ill the rot l zone can he realised not only by the seepage of groundwater from upland sandy rechar ge areas as is generally thought but also by the seepage of peat water this is important as a severe dete foration ill the quality of mdge water seeping upward on the river plain may be anticipated in tile near fut rc which forms a threat to low productivity rich fens peal water may olll r an alternativc water source ibr the conservatkm or regeneration of tow productivity rich t ns

groundwater inflow to a shallow poorly mixed wetland estimated from a mass balance of radon summary radon activity within a shallow wetland in southern australia has been measured on three occasions between may and october 2006 measured activities within the surface water display a similar pattern of spatial variability on each occasion suggesting that it is related to the locations of groundwater inflow and mixing processes the mean groundwater inflow rate has been estimated from the mean radon activity using a mass balance approach the components of the radon budget are i contribution from groundwater inflow ii diffusive flux from wetland bottom sediments iii loss due to gas exchange iv loss due to radioactive decay v loss due to groundwater or surface water outflow also required to complete the water balance are the surface water inflow rate direct precipitation on the wetland and evaporation rate the radon diffusive flux has been estimated from measurements of radon production within the sediments and a diffusive transport model calibrated by measurements of radon activity in sealed chambers that can receive radon only from diffusion and lose it only by radioactive decay radon loss due to gas exchange is inferred from the loss rate of sf6 following its injection into isolated areas of the wetland while the rate of radioactive decay is known the radon activity in groundwater inflow is measured from sampling piezometers surrounding the wetland steady state and transient mass balance approaches yield similar results with groundwater inflow rates varying between 12 and 18 m3 day estimated groundwater inflow rates are most sensitive to the radon activity of groundwater inflow the gas exchange velocity surface water area and the accuracy with which the mean radon activity in the wetland can be measured importantly it is relatively insensitive to the surface water inflow rate which is poorly known

methodological study of submarine groundwater discharge from a karstic aquifer in the western mediterranean sea summary a multiproxy approach of complementary techniques is applied to localise and quantify submarine groundwater discharge sgd from el maestrazgo jurassic aquifer an example of widespread carbonate coastal aquifer of the western mediterranean sea castellon spain unconventional water resources are critical in this area where highly populated resorts have been developed the aquifer has two main features of particular interest a karstic system with a deep saturated zone reaching 450 m and with no significant surface discharge occurring within the continental area on the other hand sgd can alter the condition of coastal marine environments reducing salinities and providing nutrients that can cause eutrophication and algal blooms the applied combined techniques make it possible to detect groundwater outflows using airborne thermal infrared tir images to monitor physico chemical anomalies in the sea and to quantify the submarine groundwater discharges by means of direct measurements and radium isotopic analyses three main coastal areas affected by sgd and a submarine spring located at 3 km from the coast which seems to be associated with tectonic discontinuities were localised the calculated fresh sgd from ra isotopes 375 mm 3 y 1 is in agreement with the mean aquifer recharge obtained by hydrogeological methods 394 mm 3 y 1

methodology of hydrogeological characterization of deep carbonate aquifers as potential reservoirs of groundwater case of study the jurassic aquifer of el maestrazgo castellon spain a methodology for the characterization of deep carbonate aquifers has been developed and applied to el maestrazgo jurassic aquifer in castellon spain characterization of these aquifer formations located at more than 300 m deep consisted of a previous phase of compilation analysis and synthesis of the existing information about the area followed by a coordinated combination of different speciality studies geology stratigraphy structural analysis hydrogeology hydrochemistry geophysics and remote sensing geological studies included geological mapping definition of stratigraphical units and facies and structural analysis the aim of the hydrogeology study was to define aquifer formations recharge area aquifer points inventory and groundwater flow directions for the establishment of piezometric and water quality observation nets special techniques were applied like thermal infrared aerial images and the evaluation of submarine groundwater discharge by means of natural radium isotopes hydrochemical techniques including majority elements characterization and stable isotopes 18o 2h and 3h determination allowed classifying hydrochemical facies and establishing a renewal pattern for water within the system geophysics was useful in determining the aquifer geometry the features of the basement and the petrophysical characteristics of the geological formations preliminary results show an important tectonic complexity and the possibilities for groundwater uses in the area of study

application of 222rn and ch4 for assessment of groundwater discharge to the coastal ocean groundwater discharge is a neglected source of freshwater and dissolved constituents to the ocean it can occur via diffuse seepage and point source spring discharge two naturally occurring trace gases 222 rn and ch 4 are present in groundwater at concentrations that are elevated by several orders of magnitude relative to seawater and they may be useful in tracing groundwater inputs to surface waters water samples collected near a submarine spring in the northeastern gulf of mexico displayed radon and methane concentrations inversely related to salinity and considerably greater than those found in surrounding waters coastal water 222 rn and ch 4 inventories varied directly with groundwater seepage rates the integrated quantities of 222 rn and ch 4 in the nearshore waters overlying a seepage meter transect showed a significant positive

north south structures in the midnight sector auroras as viewed by the viking imager during auroral substorms active auroras involving field aligned electric fields appear at the poleward border of the auroral oval equatorward of these active discrete auroras a diffuse region of luminosity develops which often features imbedded localized structures which can have distinctively north south orientations in this paper we study the behaviour of such longitudinally confined northsouth oriented auroral arc structures which may turn on and off sporadically during the substorm lifetime in particular we show observations which suggest that these structures may be the projection on the ionosphere of the drift paths of energetic electrons as they drift from the magnetotail into the more dipolar inner magnetosphere our results suggest that injection of auroral particles into the central plasma sheet occurs in quite localized regions over lengthy periods of time the injected particles drift earthward in the central plasma sheet where those electrons with pitch angles close to the loss cone are sporadically caused to precipitate into the ionosphere causing the fingers of luminosity north south aligned structures near the equatorward edge of the oval are believed to represent precipitation of a spatially localized population of energetic electrons for which the westward convective drift velocity in the evening sector nearly balances the eastward gradient and curvature drift velocity thus leading to purely earthward convective drift of the energetic electrons

ages of continental shelf waters determined from 223ra and 224ra coastal surface waters in the south atlantic bight contain elevated activities of 223ra t1 2 11 4 days and 224ra t1 2 3 66 days these elevated dissolved activities are due to continual input of the short lived tracers near the coast the presence of these tracers in an offshore water sample implies that the water is less than six half lives removed from the source of the tracer the absence of the tracer implies the water is more than six half lives old or has been diluted substantially with old water containing little tracer in this paper i use models based on 223ra and 224ra to derive ages of continental shelf waters these models compensate for tracer dilution by normalizing the short lived tracers to each other or to long lived 228ra if the water on the inner shelf 0 20 km from shore is assigned a zero age ages for waters 80 100 km from the inner shelf are 20 30 days

evaluation of salt marsh hydrology using radium as a tracer abstract radium isotopes provide unique and important information concerning water exchange in a salt marsh tidal creek system seasonal radium data collected over five tidal cycles from a creek draining a south carolina salt marsh radium and thorium data from the adjacent marsh sediments and interstitial water radium data from the drainage basin are modeled to yield residence times of water in the upper 10 cm of the marsh sediments ranging from less than one to twenty six hours water residence times derived from chambers which directly measure the flux of ra isotopes to the creek waters agree well with these calculated interstitial water turnover times dissolved radium activities in the tidal creek were greater during the summer than during other times of the year we suspect that seasonal changes in the storage of organic carbon and rates of bioturbation lead to net reduction of radium carrier phases in the marsh sediments during the summer