contrasting behaviour of anthropogenic gadolinium and natural rare earth elements in estuaries and the gadolinium input into the north sea all major rivers in northwestern germany that flow into the north sea including the weser river display rare earth element ree patterns with large positive gadolinium gd anomalies that indicate the presence of anthropogenic gd derived from contrast agents used in magnetic resonance imaging this microcontaminant cannot be removed by common sewage treatment technology and enters rivers and lakes with the discharge from waste water treatment plants as elsewhere a large fraction of the natural dissolved ree in the weser river are associated with colloids these colloids aggregate during mixing of freshwater and seawater in the low salinity part of the weser estuary and the dissolved ree are partially removed from the river water together with the colloids in marked contrast to the natural ree the anthropogenic gd behaves conservatively during this estuarine mixing and transits through the weser estuary almost unaffected this indicates that the speciation of anthropogenic gd is different from that of natural gd and suggests a long environmental half life of the anthropogenic gd complexes used as contrast agents the amount of anthropogenic gd introduced into seawater via rivers is significant and produces anthropogenic positive gd anomalies in coastal seawater this is observed in the southwestern north sea off the coast of the east frisian islands where anthropogenic gd is mostly derived from the rivers rhine and thames its long environmental half life and conservative estuarine behaviour suggest that anthropogenic gd might be utilized as a pseudo natural far field tracer for truly dissolved riverine ree input into seawater and for discharge from waste water treatment plants and for sewage in river ground and drinking water the widespread distribution of anthropogenic gd is an example of how the increasing use of exotic ultra trace elements in high tech processes will in the future significantly hamper studies of the distribution and geochemical behaviour of such elements in natural systems

brunt vaisala frequency and rossby radii in the south atlantic abstract brunt vaisala frequency profiles have been calculated in the south atlantic and neighboring regions on a 5 5 grid between 30 n and 70 s 70 w and 70 e using the annual mean temperature and salinity profiles computed by levitus from data available from the national oceanographic data center nodc these brunt vaisala frequency profiles are used in the computation of the first and second internal rossby deformation radii the external rossby radius is computed for reference these results compare very well with those of emery et at for the equatorial atlantic very small values of the radii are evidenced in the extreme south less than 10 km in the antarctic circumpolar current for the first internal mode high vertical variability in brunt vaisala frequency profiles is also observed at the center of the subtropical gyre this behavior is probably due to the lack of deep data in this region

distribution of rare earth elements and other high field strength elements in glacial meltwaters and sediments from the western greenland ice sheet evidence for different sources of particles and nanoparticles although global warming increases meltwater input into the oceans rather little is known about the distribution of high field strength elements such as the rare earths and y rey zr hf th and u in arctic glacial meltwaters and glacial fed rivers we studied glacial meltwater and glacial fed rivers from the kangerlussuaq area and a glacial fed lake and its meltwater inflow in the isua area both in the western part of the greenland ice sheet gris trace element concentrations were determined in 0 2 m filtered water samples dissolved fraction in the respective filter residues particulate fraction and in ambient sediments including cryoconite from a meltwater pond on the surface of the gris we also measured truly dissolved rey concentrations in a 10 kda ultrafiltered sample from glacial fed watson river shale normalized sn rey patterns of the particulate fraction and ambient sediments including cryoconite are rather similar to those of local archean gneisses and show positive eusn anomalies this rules out asian dust which does not show positive eusn anomalies as a possible source of these aluminosilicate particles but suggests that local archean basement is eroded and currently transported by ice water and wind to the depositional sites in front of and onto the gris all 0 2 m filtered glacial fed rivers show very unusual reysn patterns in comparison to tropical temperate and boreal rivers and are significantly enriched in light relative to heavy rey for glacial fed watson river the 99 of la and 78 of yb in the latter are associated with nanoparticles and colloids although the reysn patterns of the 0 2 m filtrates are rather similar to those of the particulate fraction and ambient sediments they lack any eusn anomalies whereas the 0 2 m filtrates from a meltwater pond on the surface of the gris show positive eusn anomalies similar to but somewhat smaller than the cryoconite while the water from the meltwater pond carries nanoparticles derived from local archean sources the lack of eusn anomalies in the glacial fed rivers suggests that their nanoparticle and colloid load represents atmospheric dust that is remobilized from greater depth in the gris most of this dust probably originated from eastern asia and shows a rey distribution similar to post archean upper continental crust i e lacks any eusn anomaly hence rey geochemistry suggests that the particulates and the nanoparticles colloids in these arctic meltwaters are derived from different sources

relative dispersion of surface drifters in the benguela upwelling region abstractwe examine the relative dispersion of surface drifters deployed in groups of triplets at the boundaries of a filament in the upwelling region off namibia for both the entire ensemble and th

the estuarine chemistry of rare earth elements comparison of the amazon fly sepik and the gulf of papua systems abstract a comparison of the amazon fly gulf of papua and sepik river systems has shown that there are two distinct processes operating on dissolved rare earth elements ree in estuaries large scale salt induced coagulation in the low salinity region and small to extensive release in the mid to high salinity region fractionation of the ree occurs during both removal and release the order of removal follows lree mree hree and the order of release follows hree mree lree where l m and h refer to light middle and heavy ree respectively hence estuarine reactions can modify the relative abundance of dissolved ree reaching the oceans operating in tandem the removal and release lead to the preferential removal of the lree and the preferential release of hree during estuarine mixing this combination in turn results in an effective river water flux river flux after modifications by estuarine chemistry which is evolved toward the ree composition of seawater which has a heavy ree enriched composition when normalized against the ree composition of rivers or the earth s continental crust the increase of dissolved ree in the mid to high salinity waters of the amazon and fly estuaries suggests a sediment and or suspended sediment source the lack of ree increases in the sepik river estuary strengthens this explanation as the mixing zone of this estuary is located over a deep shelf where there is little physical contact between bottom sediment and estuarine waters in marked contrast the amazon and fly estuaries are dominated by the active resuspension and deposition of bottom sediments the resupply of ree accompanied by fractionation may result from ree carbonate complexation during the reaction of seawater with suspended particles and or bottom sediment estuarine and shelf sediments may be important sources of dissolved nd to the oceans thereby helping to maintain the inter ocean differences in the nd isotopic composition of seawater by reducing the residence time of nd in the oceans

chemical evolution of rare earth elements fractionation between colloidal and solution phases of filtered river water abstract within the dissolved fraction of connecticut river water there is large scale fractionation of rare earth elements between colloidal and solution phases colloidal particles carry a large part of the dissolved ree pool filtration through filters with progressively smaller pore size 0 45 0 22 and 0 025 m results in filtrates with lower absolute concentrations of ree and more fractionated compositions with decreasing pore size the filtrates have shale normalized abundances which become systematically more depleted in the lree relative to the hree hence both the solution and colloidal phases are significantly fractionated with respect to the dissolved fraction these conclusions are consistent with previous studies of ree in rivers estuaries and soils and with surface solution speciation models colloids play an important role in the aquatic geochemistry of rare earth elements they are responsible for the fractionation of ree during the estuarine removal of ree the removal of suspended and colloidal particles from river water leaves the solution phase of river water with compositions of ree as evolved as those of surface seawater hence the evolution of the composition of ree in river water and seawater is significantly influenced by colloid formation during chemical weathering on the continents

anthropogenic dissolved and colloid nanoparticle bound samarium lanthanum and gadolinium in the rhine river and the impending destruction of the natural rare earth element distribution in rivers the strong increase in the consumption of rare earth elements ree in high tech products and processes is accompanied by increasing amounts of ree released into the environment following the first report of gd contamination of the hydrosphere in 1996 anthropogenic gd originating from contrast agents has now been reported worldwide from river and estuarine waters coastal seawater groundwater and tap water recently microcontamination with la that is derived from a point source where catalysts for petroleum refining are produced has been detected in the rhine river in germany and the netherlands here we report the occurrence of yet another ree microcontamination of river water in addition to anthropogenic gd and la the rhine river now also shows significant amounts of anthropogenic sm the anthropogenic sm which enters the rhine river north of worms germany with the same industrial wastewater that carries the anthropogenic la can be traced through the middle and lower rhine to the netherlands at leverkusen germany some 250 km downstream from the point source at worms anthropogenic sm still contributes up to 87 of the total dissolved sm concentration of the rhine river results from ultrafiltration suggest that while the anthropogenic gd is not particle reactive and hence exclusively present in the truly dissolved ree pool 10 kda the anthropogenic la and sm are also present in the colloidal nanoparticulate ree pool between 10 kda and 0 2 m though difficult to quantify our data suggest that the rhine river may carry up to 5700 kg of anthropogenic la up to 584 kg of anthropogenic sm and up to 730 kg of anthropogenic gd per year toward the north sea there exist no regulatory limits for dissolved ree in natural waters but total ree and y rey concentrations of up to 0 14 mg kg in the plume downstream of and 52 2 mg kg at the head of an effluent pipe at rhine km 447 3 at worms get close to and well above respectively the levels at which ecotoxicological effects have been documented because of the increasing use of ree and other formerly exotic trace elements in high tech applications these critical metals have now become emerging contaminants that should be monitored and it appears that studies of their biogeochemical behavior in natural freshwaters might soon no longer be possible

impact microcrater morphology on australasian microtektites scanning electron microscopy of 137 australasian microtektites and fragments from 4 sediment cores in the central indian ocean reveals more than 2000 impact generated features in the size range of 0 3 to 600 m 2 dominant crater number densities in m and sub m sizes therefore tektite producing impacts can lead to the generation of microcraters that mimic those found on lunar surface materials and for the lunar rocks to qualify as reliable cosmic dust flux detectors their tumbling histories and lunar surface orientations have to be known precisely

continentally derived solutes in shallow archean seawater rare earth element and nd isotope evidence in iron formation from the 2 9 ga pongola supergroup south africa abstract the chemical composition of surface water in the photic zone of the precambrian ocean is almost exclusively known from studies of stromatolitic carbonates while banded iron formations ifs have provided information on the composition of deeper waters here we discuss the trace element and nd isotope geochemistry of very shallow water if from the pongola supergroup south africa to gain a better understanding of solute sources to mesoarchean shallow coastal seawater the pongola supergroup formed on the stable margin of the kaapvaal craton 2 9 ga ago and contains banded iron formations ifs that represent the oldest documented superior type iron formations the ifs are near shore pure chemical sediments and shale normalized rare earth and yttrium distributions reysn exhibit positive lasn gdsn and ysn anomalies which are typical features of marine waters throughout the archean and proterozoic the marine origin of these samples is further supported by super chondritic y ho ratios average y ho 42 relative to older isua ifs 3 7 ga from greenland and younger kuruman ifs 2 5 ga also from south africa the pongola ifs are depleted in heavy rare earth elements hree and appear to record variations in solute fluxes related to sea level rise and fall sm nd isotopes were used to identify potential sediment and solute sources within pongola shales and ifs the nd t for pongola shales ranges from 2 7 to 4 2 and nd t values for the coeval iron formation samples range 1 9 to 4 3 are generally indistinguishable from those of the shales although two if samples display nd t as low as 8 1 and 10 9 the similarity in nd isotope signatures between the shale and iron formation suggests that mantle derived rey were not a significant nd source within the pongola depositional environment though the presence of positive eu anomalies in the if samples indicates that high t hydrothermal input did contribute to their rey signature isotopic mass balance calculations indicate that most 72 of the nd in these seawater precipitates was derived from continental sources if previous models of fe nd distributions in archean ifs are applied then the pongola ifs suggest that continental fluxes of fe to archean seawater were significantly greater than are generally considered

the behaviour of the rare earth elements during mixing of river and sea waters rare earth element concentrations have been measured in organic rich luce river water and coastal sea water concentrations e g 350 1850 pmol kg nd in the water of luce and 45 350 pmol kg nd in luce bay are related to the presence of particles with 30 60 of the ree associated with 0 4 0 7 m particles and to riverine fe concentrations ree fractionation occurs in the river water the submicrometre river water is heavy ree enriched whereas the coarser fraction has a more shale like ree pattern laboratory experiments show that the ree in organic rich river waters are chiefly associated with feorganic matter colloids which flocculate during estuarine mixing preferential removal of heavy ree 95 relative to light ree 60 occurs but no ce anomaly is developed in contrast no ree removal occurs during estuarine mixing with organic poor river water

pairwise surface drifter separation in the western pacific sector of the southern ocean the southern ocean plays a critical role in global climate yet the mixing properties of the circulation in this part of the ocean remain poorly understood here dispersion in the vicinity of the southern antarctic circumpolar current front one of the branches of the antarctic circumpolar current is studied using 10 pairs of surface drifters deployed systematically across the frontal jet and its flanks drifter pairs were deployed with an initial separation of 13 m and report their position every hour the separation of the pairs over 7 months in terms of their finite scale lyapunov exponents fsle dispersion and diffusivity is characterized and related to expected behavior from quasi geostrophic qg and surface quasi geostrophic sqg theories the fsle analysis reveals two submesoscale regimes with sqg like behavior at scales below 3 2 km and mixed qg sqg behavior at scales between 3 2 and 73 km the dispersion analysis however suggests qg like behavior for the smallest scales both dispersion and diffusivity appear isotropic for scales up to 500 km finally there is no clear indication of a cross jet variation of drifter dispersion

ree in the great whale river estuary northwest quebec we report rare earth element ree concentrations of a longitudinal profile within the estuary of the great whale river in northwest quebec and in hudson bay all of the measured ree have concentrations less than those predicted by conservative mixing of seawater and river water demonstrating removal of the ree from solution ree removal is rapid occurring primarily at salinities less than 2 removal of the ree is greatest for the light ree and ranges from about 7 for the light ree to no more than 40 for the heavy ree fe removal is essentially complete at low salinity the shape of the fe and ree vs salinity profiles is not consistent with a simple model of destabilization and coagulation of iron and ree bearing colloidal material a linear relationship between the activity of free ion ree3 and ph is consistent with a simple ion exchange model for ree removal surface and subsurface samples of hudson bay seawater are characterized by high ree concentrations and high la yb relative to average seawater the subsurface sample has a nd concentration of 100 pmol kg and an end of 29 3 0 3 these characteristics are consistent with the high ree concentration high la yb and low end of river inputs into hudson bay these results indicate that rivers draining the canadian shield are a major source of non radiogenic nd and ree to the atlantic ocean we estimate that outflow of water from hudson bay to the labrador sea could supply 30 of the non radiogenic nd in north atlantic deep water

deciphering the presence of wastewater in a medium sized mediterranean catchment using a multitracer approach abstract the impact of wastewater disposal on the water resource in a medium sized mediterranean watershed the herault river basin has been studied using a multitracer approach including no 3 cl b concentrations and the gd anomaly the herault watershed supplies drinking water to approximately 300 000 inhabitants and receives the effluents of 96 sewage treatment plants the geological context is heterogeneous with 4 main lithologies a palaeozoic basement in the north a karstified mesozoic cover in the middle an evaporite layer in the western part of the basin and alluvial deposits in the southern plain the concentration of major ca 2 cl no 3 and trace elements b sr and rare earth elements has been monitored in streams aquifers and sewage treatment plant effluents because of the particularly heterogeneous and rich geological context of the herault basin the challenge of using no 3 cl and b as wastewater tracers was to distinguish their natural and anthropogenic origins indeed none of these wastewater borne elements can be considered as a highly reliable tracer by itself because they are ubiquitous in water where they can be supplied by both natural evaporite dissolution rainfall and anthropogenic sources wastewater or agriculture however the respective contributions of different sources of candidate tracers no 3 cl and b could be roughly assessed using sr ca b sr and cl b ratios which combined with the information provided by each tracer allowed the ascertainment of the presence of wastewater in two tributaries of the herault river and in a few wells tapped for drinking water in the alluvial plain

the geochemistry of rare earth elements in the amazon river estuary abstract the estuarine geochemistry of rare earth elements rees was studied using samples collected in the amazon river estuary from the amasseds amazon shelf sediment study cruise of august 1989 extensive removal of dissolved 0 22 m filtered trivalent rees from river water occurs in the low 0 6 salinity region removal by the salt induced coagulation of river colloids leads to fractionation among the ree iii series the order of removal is light rees middle rees heavy rees there also is the enhanced removal of ce relative to trivalent la and nd in the low salinity 0 6 zone and in the zone of high biological activity this is the first field observation of strong ce removal associated with coagulation of river colloids and biological productivity the argument is made that the decrease in the ce anomaly across a biological front is caused by biologically mediated oxidation of ce iii to ce iv coagulation of river colloids and biologically mediated oxidation of ce iii lead to fractionation of ree iii and redox modification of ce these processes result in the ree composition becoming fractionated relative to the amazon river water and crust and more evolved toward the ree composition of the oceans this study implies that reactions in estuaries play significant yet poorly understood roles in controlling the ree composition and ce anomaly of the oceans

geochemical behaviour of rare earth elements ree along a river reach receiving inputs of acid mine drainage abstract total and dissolved rare earth elements ree were studied in a river reach affected by several inputs of acid mine drainage the first four acidic discharges were of lesser importance compared to the last agrio river coming from the rio tinto mines which transported high loads of fe and al 2 1 and 4 2 ton day respectively together with ree 16 4 kg day and other trace elements in the acid mine drainage amd sources practically all the ree were dissolved and the north american shale composite nasc normalized patterns showed an enrichment in medium ree although some differences exist between the patterns of each source the ph values in the river reach upstream of the confluence with the agrio river ranged between 8 01 and 7 03 and most of the fe and al from the amd sources precipitated downstream of this acidic discharge the ph decreased to 2 98 upstream of the first amd input the dissolved and total concentrations of ree were very low 7 concentrations of ree increased up to 25 g l mainly transported by the particulate phase in the reach downstream of the agrio river with acidic conditions ree behaved conservatively the ree nasc normalized patterns of the river samples resemble that of the amd sources although an enrichment of heavy ree in the dissolved phase is observed linked to complexation by carbonates cerium and particularly la also show higher dissolved percentages similar to hree which must be due to the lower affinity of these elements to be sorbed onto fe oxyhydroxides variations in ce and eu anomalies are observed along the river reach as a consequence of the different amd inputs however the values of the ce anomaly are higher in total samples than in dissolved samples speciation results indicate that these differences are not caused by differences in oxidation states but by slight differences in the hydrogeochemical behaviour of ce with respect to la and nd

the estuarine geochemistry of rare earth elements and indium in the chao phraya river thailand abstract a new filtration method using a 0 04 m hollow fiber filter was applied to the river estuarine and coastal waters in the chao phraya estuary for geochemical investigation the filtered waters were analyzed for all the lanthanides y and in by using inductively coupled plasma mass spectrometry icpms the dissolved concentrations of rare earth elements rees are significantly lower than those reported previously for other rivers presumably because of effective removal of river colloids by the ultra filtration the variation of dissolved rees in the estuary is dependent on the season the light rees vary considerably in the low salinity s 3 show almost conservative trends being consistent with some of the previous works europium is strongly enriched in the river and estuarine waters compared to the south china sea waters thus the ree source of the chao phraya river must be fractionated and modified in entering to the south china sea dissolved in and ce in the high salinity s 20 25 zone of the estuary are lower than those of the offshore waters and therefore the dissolved flux of the chao phraya river cannot account for the higher concentrations of dissolved in and ce in the surface waters of the south china sea the negative ce anomaly is progressively developed with increasing salinity being consistent with continued oxidation of ce iii to ce iv in the estuary fractionation of the light to heavy rees seems to take place whereas the y ho fractionation is unclear in the estuarine mixing zone

the geochemistry of rare earth elements in the seasonally anoxic water column and porewaters of chesapeake bay a twelve cruise time series study of a seasonally anoxic basin in chesapeake bay was carried out between february 1988 and february 1989 data from filtered bottom water and upper 0 1 cm porewater samples are presented this is the first study in which time series measurements have been employed to understand the low temperature geochemistry of rare earth elements rees the focus is on the coupling between redox reduction oxidation variations and ree cycling fractionation of trivalent rees and development of cerium anomalies the time series results demonstrate that rees have large seasonal cycles in both the water column and porewaters in response to the development of anoxia in the spring and reoxygenation in the fall the transition from oxic to suboxic to anoxic conditions results in the release of rees into the upper porewaters and bottom waters the release of rees and fe are coincident in the bottom waters while the release of rees lags fe by approximately 50 days in the upper porewaters this decoupling is explained in terms of a redox front which moves upward from the sediments to bottom waters during the development of seasonal anoxia the release of rees to the upper porewaters and bottom water are accompanied by 1 1 fractionation across the trivalent ree series and by 2 2 the preferential input of ce relative to its trivalent only ree neighbors ree iii fractionation is such that the relative rate of release increases from lu to la light ree middleree heavyree during reoxygenation removal of dissolved rees occurs from both the water column and upper porewaters and follows the same relative rates lree mree hree cerium removal occurs faster than its neighbor ree iii indicating a rapid oxidation of ce iii to ce iv

surface drifter pair spreading in the north atlantic 1 this study examines spreading of surface drifter pairs deployed as part of the clivar mode water dynamic experiment climode project in the gulf stream region the spreading is resolved at hourly resolution and quantified by relative dispersion and finite scale lyapunov exponents at scales from 1 3 km to 300 500 km the dispersion follows richardson s law indicating stirring by eddies comparable in scale to the pair separation distance at larger scales the spreading becomes a random walk described by a constant diffusivity the behavior from 1 3 km to the local deformation radius is inconsistent with the enstrophy cascade of 2 d quasigeostrophic turbulence to test various hypotheses for this result drifter pair spreading is examined for pairs that were not launched together pairs deployed in the eastern subtropical north atlantic and climode pairs subsampled to daily temporal resolution our results indicate the presence of significant energy at the submesoscale in the gulf stream region which flattens the wave number spectrum and dominates surface stirring at this scale range results in the less energetic subtropical eastern atlantic are more equivocal

lagrangian drifter dispersion in the southwestern atlantic ocean abstractin the framework of monitoring by ocean drifters mondo project a set of lagrangian drifters were released in proximity of the brazil current the western branch of the subtropical gyre in the south atlantic ocean the experimental strategy of deploying part of the buoys in clusters offers the opportunity to examine relative dispersion on a wide range of scales adopting a dynamical systems approach the authors focus their attention on scale dependent indicators like the finite scale lyapunov exponent fsle and the finite scale mean square relative velocity fsrv between two drifters as a function of their separation and compare them with classic time dependent statistical quantities like the mean square relative displacement between two drifters and the effective diffusivity as functions of the time lag from the release the authors find that dependently on the given observable the quasigeostrophic turbulence scenario is overall compatible with their data analysis with discrepancies fr

rare earth element behavior during groundwater seawater mixing along the kona coast of hawaii abstract groundwater and seawater samples were collected from nearshore wells and offshore along the kona coast of the big island of hawaii to investigate rare earth element ree behavior in local subterranean estuaries previous investigations showed that submarine groundwater discharge sgd is the predominant flux of terrestrial waters to the coastal ocean along the arid kona coast of hawaii groundwater and seawater samples were filtered through 0 45 m and 0 02 m pore size filters to evaluate the importance of colloidal and soluble i e truly dissolved ionic species and or low molecular weight lmw colloids fractions of the rees in the local subterranean estuaries mixing experiments using groundwater collected immediately down gradient from a wastewater treatment facility wwtf proximal to the kaloko hanokohau national historic park and more pristine groundwater from a well constructed in a lava tube at kiholo bay were conducted with local seawater to study the effect of solution composition i e ph salinity on the concentrations and fractionation behavior of the rees as groundwater mixes with seawater in kona coast subterranean estuaries the mixed waters were also filtered through 0 45 or 0 02 m filters to ascertain the behavior of colloidal and soluble fractions of the rees across the salinity gradient in each mixing experiment concentrations of the rees were statistically identical two tailed student t test 95 confidence between the sequentially filtered sample aliquots indicating that the rees occur as dissolved ionic species and or lmw colloids in kona coast groundwaters the mixing experiments revealed that the rees are released to solution from suspended particles or colloids when kona coast groundwater waters mix with local seawater the order of release that accompanies increasing ph and salinity follows light ree lree middle ree mree heavy ree hree release of rees in the mixing experiments is driven by decreases in the free metal ion activity in solution and the concomitant increase in the amount of each ree that occurs in solution as dicarbonato complexes i e ln co3 2 as ph increases across the salinity gradient input normalized ree patterns of kona coast groundwater and coastal seawater are nearly identical and relatively flat compared to north pacific seawater indicating that sgd is the chief source of these trace elements to the ocean along the kona coast additionally ree concentrations of the coastal seawater are between 10 and 50 times higher than previously reported open ocean seawater values from the north pacific further demonstrating the importance of sgd fluxes of rees to these coastal waters taken together these observations indicate that large scale removal of rees which characterizes the behavior of rees in the low salinity reaches of many surface estuaries is not a feature of the subterranean estuary along the kona coast a large positive gadolinium gd anomaly characterizes groundwater from the vicinity of the wwtf the positive gd anomaly can be traced to the coastal ocean providing further evidence of the impact of sgd on the coastal waters estimates of the sgd fluxes of the rees to the coastal ocean along the kona coast i e 1 3 2 6 mmol nd day 1 are similar to recent estimates of sgd fluxes of rees along florida s east coast and to rhode island sound all of which points to the importance of sgd as significant flux of rees to the coastal ocean

the near surface dynamics of coastal upwelling abstract an attempt is made to examine some observational and theoretical aspects of upper ocean dynamics in regions of strong coastal upwelling upper ocean is roughly defined as about the upper 10 30 m of the water column for most systems first the basic surface ekman and mixed layers are discussed including some of the modifications due to upwelling next coastal upwelling fronts and their associated circulation are treated finally areas of strongly three dimensional upwelling are classified and discussed horizontal advection of heat and momentum appear to be generally important for the near surface dynamics of coastal upwelling and these phenomena make realistic theoretical treatments especially difficult

fluid source and methane related diagenetic processes recorded in cold seep carbonates from the alvheim channel central north sea integrated petrography mineralogy geochronology and geochemistry of cold seep carbonate crusts and free gas from the alvheim channel elucidate diagenetic carbonate precipitation and related seepage histories in the central north sea free gas isotope characteristics coupled with carbonate 13c values as low as 66 vpdb indicate a predominantly microbial methane source with minor thermogenic contribution we estimate that 70 of the carbon sequestered into carbonate precipitates was derived from local oxidation of methane the early stage of crust growth is represented by microcrystalline aragonite and mg calcite 10 to 40 mol mgco3 cementing seafloor sediments consisting of clays quartz feldspar and minor detrital low mg calcite and dolomite typical association of aragonite cement with coarse grained detritus may reflect elevated fluid flow and flushing of fine particles prior to cementation close to the seafloor middle rare earth element enrichment in early generation microcrystalline cements containing framboidal pyrite indicates diagenetic precipitation within the zone of anaerobic methane oxidation contiguous to iron reduction the later generation diagenetic phase corresponds to less abundant radial fibrous and botryoidal aragonite which lines cavities developed within the crusts in contrast to early generation cements late generation cavity infills have rare earth elements and y patterns with small negative ce anomalies similar to seawater consistent with carbonate precipitation in a more open seawater dominated system aragonite u th ages indicate carbonate precipitation between 6 09 and 3 46 kyr bp in the northern part of the channel whereas in the southern part precipitation occurred between 1 94 and 0 81 kyr bp reflecting regional changes in fluid conduit position

targeted lagrangian sampling of submesoscale dispersion at a coastal frontal zone 1 the potential impact of rapidly evolving submesoscale motions on relative dispersion is at the forefront of physical oceanography posing challenges for both observations and modeling a persistent coastal front driven by river outflows in the north western mediterranean sea is targeted by two observational cruises conducted in the summer of 2010 the frontal zone is sampled using drifters launched with a multi scale strategy consisting of modules of triplets released on either side of the front by small boats this experiment is original in that the submesoscale range of 100 m to 1000 m is directly targeted and the results are expected to provide guidance for practical applications such as prediction of the initial spreading of pollutants and biogeochemical tracers the influence of submesoscale motions on relative dispersion is quantified using both particle mean square separation as a function of time and scale dependent finite size lyapunov exponents fsle our main finding is the identification of a local dispersion regime with values reaching as high as 20 days 1 at drifter pair separation distances of 100 m this value is more than an order of magnitude greater than that obtained by drifters in the offshore ligurian current the ligurian sea circulation is modeled using a fully realistic regional ocean modeling system roms with 1 60 horizontal resolution it is found that the numerical model significantly underestimates the relative dispersion at submesoscales indicating the need for particle dispersion parameterizations for unresolved processes

surface relative dispersion in the southwestern gulf of mexico abstractsurface dispersion properties in the southwestern gulf of mexico are studied by using a set of 441 drifters released during a 7 yr period and tracked for 2 months on average the drifters have a drogue below the surface ekman layer so they approximately follow oceanic currents this study follows two different approaches first two particle or pair statistics are calculated relative dispersion and finite scale lyapunov exponents fsles relative dispersion estimates are consistent with theoretical dispersion regimes of two dimensional turbulence an exponential growth during the first 3 days a richardson like regime between 3 and 20 days in which relative dispersion grows as a power law in time and standard dispersion linear growth for longer times the fsles yield a power law regime for scales between 10 and 150 km but do not detect an exponential regime for short separations less than 10 km robust estimates of diffusivities based on both relative dispersion and fsles are provided

seasonal variations of rare earths and yttrium distribution in the lowland havel river germany by agricultural fertilization and effluents of sewage treatment plants abstract ree and y rey distribution in the lowland havel river passing the federal state of berlin germany depends on contributions of point sources such pharmaceutical and high tech industries acid water from the open pit lignite mining and medical application of very stable organic gd chelates another omnipresent dispersed source of rey are water soluble ca phosphates containing micro amounts of eu ii bearing barite as components of common agricultural fertilizers after distribution in the field during the cold season october through march these ca phosphates dissolve and secondary phosphates and calcite precipitate both being enriched in light ree heavy ree are preferably exported by runoff together with part of the micro contaminant barite leading to high yb nd ratios in the havel water and rey distribution patterns with only small eu deficits during the warm season april through september light ree together with phosphate are leached from secondary soil minerals by runoff the micro component barite is retained in vegetation covered soil thus rey patterns of havel water show significant eu deficits the high gd anomalies result from medical applications of gd chelates which after urination pass the sewage treatment plants the seasonal variations of total gd in the havel river are artifacts based on seasonal locally varied discharge of effluents from sewage treatment plants the natural gd concentration of 8 pmol l in the northern havel is enhanced to 3300 pmol l when the havel river leaves berlin territory the elimination of phosphate from lake tegel water affects the fractionation of ree but not the concentration of total gd although enhanced in total phosphorus tp the ree concentrations in the water from the spree river and the teltow canal are less than in the havel water before their confluence only yb and lu do not decrease the contributors of the havel river are high in total organic carbon toc and dissolved organic carbon doc compared to the havel water before their indicating that rey are preferentially sorbed by settling organic matter applying phreeqc and assuming that only 10 of tp is present as ortho phosphate yields that only carbonate complexes are essential