new insights into the palaeoenvironmental evolution of magdala ancient harbour sea of galilee israel from ostracod assemblages geochemistry and sedimentology abstract despite several studies have focused on the past bio sedimentary response of the mediterranean coastal areas to ancient seaport activities only few geoarchaeological and palaeoecological data are available on strictly lacustrine harbours to date at the archaeological site of magdala taricheae sea of galilee north israel an interdisciplinary study combining ostracod fauna composition and shell chemistry with sedimentology geochemistry of sediments and archaeological data was undertaken on the sedimentary succession buried beneath the roman harbour structures in correspondence of two key sections this approach provided detailed information about past environmental changes otherwise not visible into a high resolution pottery based chronological framework at the transition from a natural pre harbour to anthropogenically influenced harbour lacustrine depositional setting new bio sedimentary and archaeological pottery data document that remarkable hydrodynamic and hydrochemical changes took place during the hellenistic period from the 3 rd 2 nd century bc to the first half of the 1 st century ad in response to the construction of the oldest magdala harbour installations and possibly to the following hasmonean structures the high v cr concentrations observed in the harbour sediments and the substantial increase of ostracod species pseudocandona albicans preferring slow moving waters and fine grained substrates point to the establishment of a semi enclosed shallow and organic rich setting coupled ostracod geochemical analyses also testify to an alkali ions na and k enrichment within whole sediment samples reasonably driven by increasing evaporation in response to the partial isolation of the lake margin the increase in sodium and potassium concentrations is accompanied by the sudden appearance of heterocypris salina a brackish tolerant species and by the almost absolute dominance of noded valves of cyprideis torosa whose shells are enriched in na k and cl the positive covariance between na 2 o k 2 o values and the frequencies of noded c torosa seems to confirm the relation between node development and changes in ionic concentration within hypohaline settings

88 sr 86 sr fractionation and calcite accumulation rate in the sea of galilee abstract this study used the sea of galilee lake kinneret northern israel as a natural laboratory to investigate the fractionation of the stable sr isotope ratio 88 sr 86 sr during precipitation of inorganic primary calcite from the lake s water it was found that the absolute value of the 88 sr 86 sr fractionation factor 88 86 sr increases as a function of calcite accumulation rate 88 86 sr 0 05 to 0 042 log r mol m 2 d 1 where r is the accumulation rate furthermore the 87 sr 86 sr and 88 sr 86 sr ratios in the freshwater and brines that enter the lake were used to calculate the contributions of these sources to the lake sr budget the 87 sr 86 sr and 88 sr 86 sr ratios were measured in primary calcite aragonite shells of live melanopsis lake water and various water sources to the lake while the lake s 87 sr 86 sr ratios are determined by the mixture of freshwater of the jordan river and saline springs the 88 sr 86 sr ratios of the lake reflect a more complex mass balance that includes the effect of isotopic fractionation associated with the precipitation of primary calcite data analysis suggests that long term accumulation of inorganic calcite depleted in the heavy isotope 88 sr results in an increase of the 88 86 sr value of the lake water by 0 05 in contrast to the primary inorganic calcite biogenic aragonite of the melanopsis shells show a rather constant 88 sr 86 sr water caco 3 fractionation of 88 86 sr 0 21 similar 88 86 sr values were reported for the precipitation of coralline and inorganic aragonite from seawater and the precipitation of inorganic calcite from various continental waters the 88 86 sr value of inorganic calcite is modulated by the rate of carbonate precipitation as noted above and shown by precipitation experiments massive precipitation of primary calcite with a wide spread of accumulation rates occurs during the spring phytoplankton bloom in lake kinneret the bloom dictates the degree of calcite saturation in the lake and hence the stable sr isotopic composition of the precipitating calcite the correlation between 88 sr 86 sr and the calcite accumulation rate can be therefore used as a tool to reconstruct environmental and ecological variations in the historical lake by analyzing the 88 sr 86 sr ratio in the primary caco 3 recovered from the lake s sedimentary archives

hydrologic fragmentation induced eutrophication in dove sound upper florida keys usa anthropogenic impacts to island systems can have deleterious effects on coastal aquatic ecosystems these effects can alter water quality primary production as well as habitat land development often fragments hydrologic connectivity within aquatic ecosystems forcing alterations in nutrient transport and increases the potential for eutrophication dove sound a tidal lagoon located in the upper florida keys on key largo has been subjected to anthropogenic influences of land development during the last century to investigate these influences a short sediment core was collected from within dove sound and investigated using 210pb dating stable isotopes of carbon and nitrogen and sedimentary pigments results indicated that dove sound has undergone eutrophication and the primary producer community structure has shifted from dominantly macrophytic to a system that supports substantial algal production while septic waste was a possible source for eutrophication low 15n did not support this conclusion however the timing of the shifts in dove sound along with indicators of anoxia leads to the conclusion that fragmentation caused by the construction of a railroad was the root cause the hydrologic fragmentation reduced the flushing rates thereby enhancing anoxic conditions in the system and increasing the internal nutrient loading

quantifying saline groundwater flow into a freshwater lake using the ra isotope quartet a case study from the sea of galilee lake kinneret israel we investigated the ra isotope quartet in order to quantify the discharge of saline groundwater into a freshwater lake the activities of 226ra 228ra 223ra and 224ra were measured in the sea of galilee israel surrounding saline springs and the jordan river coupled with u th and 226ra measurements in sediment cores and laboratory ra adsorption experiments under different salinity conditions the 226 ra activity 0 007 0 008 bq l 21 and 226 ra cl ratio in the lake were significantly lower than those of the inflowing saline springs indicating that 75 86 of the incoming 226 ra is removed from the lake water this missing ra is likely adsorbed onto suspended particles given the observed differential depletion of ra isotopes we present a model consisting of adsorption desorption recoil and decay of the short lived 224 ra and 223 ra isotopes we predict a removal time of 2 weeks for ra inferring the apparent residence time of suspended matter in the lake a mass balance calculation of the different 226ra inventories reveals a saline groundwater flux of 44 61 3 109 ly r 21 for fuliyatype water the residence time of dissolved 226ra in the lake is estimated as 3 4 yr the 228ra 226ra ratio of the lake water and a mass balance calculation show that 228ra arrives from regeneration though bottom sediments in addition to groundwater flux mass balance calculations of the expected saline fluxes before the diversion of saline inflows to the lake early 1960s provide 226ra activity estimates in the lake 0 018 0 020 bq l21 that are similar to the value 0 018 6 0 0001 bq l21 measured in the lake in 1962

lake kinneret the sea of galilee the effects of diversion of external salinity sources and the probable chemical composition of the internal salinity sources this paper investigates the chemical variations and evolution of lake kinneret lk the sea of galilee after the diversion of onshore saline springs through the salinity diversion channel sdc which reduced the salinity of the lake water the mass balance approach enables to determine the average chemical composition of the unknown internal lake sources of salinity that in addition to other known sources contribute salts and control the chemistry of the lake water this study reveals for the first time the average chemical composition of the internal lake salinity sources mass balances show that the water discharge of the lake internal sources is 61 106 m3 year 1 and that these sources contribute 72 000 tons of chloride annually the sdc operation caused a long term decrease in the concentrations of cl mg na k ca so4 and br in lake water concomitantly the ionic ratios of na cl mg cl ca cl k cl and so4 cl have increased and br cl ratio has decreased the average chemical composition of the lake internal sources is characterized by na cl and mg cl ionic ratios which closely resemble those measured in the two well known submerged saline springs of fulyia a and fulyia b and in water of a deep observation well located north of the lake referred to as kin 8 the decrease in br cl ionic ratio from 3 58 10 3 prior to the sdc operation to 3 29 0 11 10 3 in mid 1990s implies that the major internal sources of cl and br to the lake are characterized by br cl ratios 3 29 10 3 br cl ionic ratios somewhat lower than 3 29 10 3 were found only in fulyia a and fulyia b springs and in kin 8 water it is therefore suggested that fulyia like water is the internal saline source which supplies most of the na cl and br to the lake sulphate however is contributed to the lake mainly over 80 through freshwater streams calcium and alkalinity originate mainly from freshwater sources including internal lake flow of groundwater lower in salinity but saturated with caco3 thus internal sources of solutes are mostly composed of the saline end member of fulyia like water and of fresher groundwater these conclusions have practical implications for lake water management

the origin of brines underlying lake kinneret abstract lake kinneret lk is a relatively fresh water lake situated in the dead sea rift dsr valley the pore water pw in the sediments underlying lk pelagic zone have significantly higher salinity than that of the lake the concentrations of major ion solutes cl br na k mg in pw from six 2 4 m to 5 1 m long sediment cores increase linearly with depth indicating the occurrence of saline deep seated brines the upper part of the pw column is affected by the much fresher boundary with lk water and in most cores is characterized by gradually increasing br cl and decreasing na mg k cl molar ratios which tend to stabilize at about 2 0 m below the sediment surface the stable molar ratios in the deeper pw vary spatially and are supposed to represent the ratios in the deep underlying brines at each site when plotted as na cl vs br cl the stable ratios of the northern and central part of the lake fall close to a straight line which characterizes many of the brines in the dsr valley however the respective ratios in the southern part of the lake fall markedly off the dsr line moreover na cl and k cl molar ratios in the south are significantly higher than in the central and northern parts 37 cl measured in present lk water is ca 0 0 along the pw column at the lake center 37 cl is becoming more positive with depth reaching values of about 0 5 to 0 6 at 3 m depth even more positive values 0 7 to 0 8 are detected further north in pw from deeper sediment layers in contrast in pw from the southeastern part of the lake 37 cl is becoming more negative with depth 1 0 at 2 6 m it is suggested that these isotopic differences are also indicative of spatial variability in the pw brine sources 18 o and d values in the pw of all 3 m long cores are similar and resemble the respective levels in lk the source of h 2 o in 3 m deep bed sediments is claimed to be the overlying lake water and therefore water isotopes do not provide a clue regarding the original water isotopic composition in the underlying brines pw from the southeast with higher k cl and na cl but lower concentrations of these solutes suggest leaching by meteoric water of sub surface halite and post halite salt formations while the more saline pw from the northern and central parts that have lower k cl and na cl and higher br cl are similar to dsr brines and represent underlying residual brines

boron isotope geochemistry of thermal springs from the northern rift valley israel a boron isotope study was carried out on groundwaters from the northern rift valley israel the relatively high salinity 18 000 mgcl l 1 boron content 3 9 mg l 1 and 11 b value 44 and the low b cl ratios of the saline tiberias hot spring suggest dilution of deepseated trapped cacl2 brines with a 11b 44 which is consistent with previous interpretations based on na cl 0 58 and 18o 3 values the 11b values of the springs in hammat gader decrease gradually from 11b of 41 9 to 20 9 with increasing salinity 70 to 497 mgcl l 1 temperature 25 50 c and boron content 0 1 0 3 mg l 1 the 11b values suggest that boron is derived from leaching of calcium carbonate or desorption of clay minerals of a 11b 14 and mixing with meteoric water of a high 11b value the relatively low 11b values of two low salinity springs 1240 and 2700 mgcl l 1 along the sea of galilee 11b 31 6 and 31 8 and the lake itself 24 suggest that a significant fraction of boron in these waters is also derived from rock leaching the influence of boron that is leached from the rocks is limited and can be recognized mainly in boron depleted groundwater the variations of 11b na cl and 18o parameters in the hammat gader springs demonstrate the sensitivity of each element to different sources whereas oxygen isotope compositions reflect the meteoric source the major ions e g na cl and br cl ratios record the influence of the deep seated brines and boron isotopes in diluted groundwater are sensitive to water rock interaction

the stable oxygen and carbon isotopic record from a coral growing in florida bay a 160 year record of climatic and anthropogenic influence abstract a 160 year record of skeletal 13 c and 18 o was examined in a specimen of the coral solenastrea bournoni growing in florida bay variations in the 18 o of the skeleton can be correlated to changes in salinity while changes in the 13 c reflect cycling of organic material within the bay based on the correlation between salinity and skeletal 18 o we have concluded that there has been no long term increase in salinity in this area of florida bay over the past 160 years using salinity correlations between the various basins obtained from instrumental data we have been able to extend our interpretations to other parts of florida bay reaching similar conclusions in contrast to current ideas which have focused on changes in florida bay water quality over the past 20 yr history of the bay as causative in its decline we have determined that changes in water quality in this basin were already set in motion between 1905 and 1912 by the construction of the florida east coast railway from miami to key west the construction of the railway resulted in the restriction of the exchange of water between the florida reef tract and the gulf of mexico causing florida bay to become more eutrophic evidence of this process is observed in the sudden shift to relatively lower 13 c values coincident with railway construction natural events also appear to have influenced the water in the bay between 1912 and 1948 frequent hurricanes had the effect of increasing exchange of water between the bay and reef tract and removing large quantities of organic rich sediments however since 1948 the number of hurricanes affecting the area has decreased and the products of the oxidation of organic material have been increasingly retained within the basin promoting the initiation of eutrophic conditions

temporal variability of carbon and nutrient burial sediment accretion and mass accumulation over the past century in a carbonate platform mangrove forest of the florida everglades the objective of this research was to measure temporal variability in accretion and mass sedimentation rates including organic carbon oc total nitrogen tn and total phosphorous tp from the past century in a mangrove forest on the shark river in everglades national park usa the 210pb constant rate of supply model was applied to six soil cores to calculate annual rates over the most recent 10 50 and 100 year time spans our results show that rates integrated over longer timeframes are lower than those for shorter recent periods of observation additionally the substantial spatial variability between cores over the 10 year period is diminished over the 100 year record raising two important implications first a multiple decade assessment of soil accretion and oc burial provides a more conservative estimate and is likely to be most relevant for forecasting these rates relative to long term processes of sea level rise and climate change mitigation second a small number of sampling locations are better able to account for spatial variability over the longer periods than for the shorter periods the site average 100 year oc burial rate 123 19 standard deviation g m 2 yr 1 is low compared with global mangrove values high tn and tp burial rates in recent decades may lead to increased soil carbon remineralization contributing to the low carbon burial rates finally the strong correlation between oc burial and accretion across this site signals the substantial contribution of oc to soil building in addition to the ecosystem service of co2 sequestration

preservation of elemental and isotopic source identification of sedimentary organic matter the amount and type of organic matter in the sediments of lakes and oceans contribute to their paleoenvironmental and paleoclimatological records only a small fraction of the initial aquatic organic matter survives destruction and alteration during sinking and sedimentation selective degradation modifies the character of the surviving small fraction of organic matter which becomes incorporated in bottom sediments organic matter alterations can continue to sub bottom depths of hundreds of meters corresponding to millions of years source and paleoenvironmental information nonetheless remains preserved in the molecular elemental and isotopic compositions of organic matter c n and 13c values of total organic matter in particular appear to retain paleoenvironmental information for multi myr time periods

a multi proxy μ xrf inferred lake sediment record of environmental change spanning the last ca 2230 years from lake kanono northland new zealand abstract reliable interpretation of annual resolution climate proxies for wind precipitation and detrital influx are required for identifying the onset and periodicities of climatic events in particular this is essential for the evaluation of inter annual decadal and centennial trends driven by shifting positions of the southern westerly winds sww and subsequent storm belts associated with the southern annular mode sam and el nino southern oscillation enso here we present a quasi annual data set of xrf time series spanning ca 2230 years from lake sediment cores from lake kanono northland new zealand the xrf time series were interpreted using a combination of principal component analysis pca and cluster analysis then verified with comparison to regionally averaged empirical rainfall and wind climate station data our results show that the wavelet patterns align with the pca results allowing the xrf time series to be classified into group i detrital and group ii biological productivity and normalized climate proxies the normalized group ii xrf time series wavelet analyses displayed periodicities in the 2 16 year frequency likely associated with enso from ca 237 bce 1330 ce the data show clear evidence of both polynesian and european settlement phases in this part of northern new zealand and that polynesian settlement impact was coeval with changes in enso intensity and a phase shift in sam ca 1350 ce the medieval climate anomaly mca and the little ice age lia appear in the xrf time series data as separate clusters this data suggests that the mca is associated with windy dry conditions with intermittent storminess during the lia the 2 16 year periodicity associated with enso decreased and centennial to multi decadal length periodicities increase which may be an indication of an underlying sam signal within the data european settlement also had a direct impact on the lake basin via increased detrital influx likely from farming activities and intensification of local forestry operations

influence of boundary scavenging and sediment focusing on 234th 228th and 210pb fluxes in the santa barbara basin abstract sediment trap samples were collected from the santa barbara basin to examine the flux of 234 th 228 th and 210 pb mean ratios of measured to predicted fluxes are 2 10 and 21 for 234 th 228 th and 210 pb respectively boundary scavenging may supply a portion of all three radionuclides however sediment focusing supplies additional 228 th and 210 pb but little 234 th sediment temporarily deposited on the shelf around the basin contains little excess 234 th due to its short half life 228 th and 210 pb fluxes to the sediments in the santa barbara basin are several times greater than predicted from their supply in the overlying water column these enhanced fluxes require lateral transport of 228 th and 210 pb to the basin through boundary scavenging and sediment focusing 234 th flux is poorly correlated with 228 th and 210 pb fluxes because individual radionuclide sources to the basin differ i e water column production boundary scavenging and or sediment focusing correlations between 228 th and 210 pb fluxes are high due to the strong influence of sediment focusing on both radionuclides there is a strong correlation between both the 228 th and 210 pb flux and total mass flux and lithogenic flux but a weak correlation with the other major sediment components e g organic carbon carbonate and biogenic opal in the santa barbara basin a large fraction of the total mass flux is lithogenic material 50 80 hence the strong correlation between 228 th and 210 pb fluxes and both total mass and lithogenic fluxes 234 th flux is poorly correlated with total mass and major sediment component fluxes

the phosphorus cycle phosphogenesis and marine phosphate rich deposits abstract phosphorus in the form of phosphate is an essential nutrient and energy carrier on many different levels of life and a key element in mediating between living and lifeless parts of the biosphere one of the most important aspects of the phosphorus cycle is its vital role in governing productivity thereby interacting with the exogenic part of the carbon cycle which in turn is important in regulating earth s climate phosphorus is a prime element to be traced in earth s history because it allows for the reconstruction of long term feedback mechanisms between climate environment and ecology and of global change as such marine sedimentary phosphate deposits are particularly suited to study aspects of the phosphorus cycle because in the case of ubiquity their origin may result from a general acceleration of the global phosphorus cycle sources of sedimentary phosphate are microbial breakdown of buried organic matter and redox driven phosphate desorption from iron and manganese oxyhydroxides dissolved sea water phosphate represents an additional source which may become important in the formation of phosphatic hardgrounds the main locus of phosphogenesis is near the sediment water interface but phosphogenesis also occurs at greater sediment depths current induced winnowing and transport processes along the sea floor concentrate phosphate precipitates into deposits which exhibit internal stratification patterns typical for the prevailing hydraulic energy regime in a sequence stratigraphic context phosphate deposits preferentially occur along marine or maximum flooding surfaces consequent sedimentary reworking may result in the transfer of phosphates to highstand or lowstand deposits bio chemical weathering on continents represents the most significant source of bioavailable phosphorus this implies that long term changes in marine phosphorus levels and with these changes in marine ecology productivity rates and ratios of exported carbonate carbon and organic carbon are a response to changes in continental weathering rates a compilation of marine sedimentary phosphorus burial rates for the last 160 myr suggests that natural variations have occurred that span one order of magnitude for the late jurassic cretaceous and most of the paleogene the phosphorus cycle appears to have been accelerated in times of climate warming which was most likely due to the spreading of zones of humid climate and more intense continental weathering in the neogene the phosphorus cycle appears to have responded to changes in glacially induced weathering this suggests that uniform interpretations with respect to the emplacement of major phosphorite deposits should be treated with caution integrated analyses of the sedimentary and biogeochemical context of phosphorite occurrences may help to identify paleoenvironmental conditions as well as to improve our understanding of periods of enhanced phosphate accumulation periods which were usually characterized by steep gradients in the development of climate and environment with regard to the complexity of feedback mechanisms between the phosphorus cycle and the biosphere the present day input rates of phosphate into the world s oceans should be of great concern they are more than doubled by anthropogenic means and affect ecological systems on a rapidly increasing scale

calcium magnesium and strontium cycling in stratified hardwater lakes lake kinneret sea of galilee israel abstract in stratified hardwater lakes calcite crystallization in the epilimnion and partial dissolution in the hypolimnion play important roles in the cycling of ca2 in the water column mg2 and sr2 coprecipitate with this mineral to be released together with ca2 upon its dissolution here we focus on lake kinneret sea of galilee israel a stratified warm hardwater lake searching for an interpretable high resolution picture of the processes that drive ca2 mg2 and sr2 cycling in this and similar lakes elsewhere in total 1428 water samples were collected from the lake and another 81 samples were collected from the jordan river and two small streams discharging into it covering a full monomictic cycle from december 2001 through march 2003 particulate material was retrieved from sediment traps in the hypolimnion the water samples were analyzed for na k mg2 ca2 sr2 cl so42 hco3 and br and the trapped particulates were examined under sem and analyzed for their ca mg and sr content individual calcite crystals within the particulate material underwent la icp ms analysis for ca mg and sr downward transport of ca2 involves crystallization of calcite in the epilimnion followed by its settling through the water column followed by its partial dissolution in the hypolimnion magnesium and sr2 follow ca2 by coprecipitation in calcite and are released upon its dissolution in the hypolimnion upward cycling of the three solutes occurs through an admixture of the hypolimnetic water into the epilimnion during thermocline deepening terminated by overturn of the lake removal rates of mg2 and sr2 from the lake relative to that of ca2 and the water calcite distribution coefficients dmg and dsr were calculated from the analyses using 1 epilimnion water and bulk particulates 2 epilimnion water only and 3 epilimnion water and calcite crystals in the particulates the dsr values obtained were internally consistent 0 194 5 9 0 22 0 28 and 0 204 0 232 respectively however the dmg value for the bulk particulates 0 0477 was 6 times higher than that corresponding to calcite crystals included therein 0 00841 this difference is attributed to phytoplankton debris in the bulk particulates and should be of concern to geochemists using mg ca ratios in limestone to reconstruct ancient aquatic environments the cycling of ca2 mg2 and sr2 in the stratified lake is monitored by mg ca vs sr ca regression diagrams where each line represents the water column composition on a specific date the distance of the data points from the initial mixed lake coordinates reflects the fractionation of ca2 mg2 and sr2 after the onset of stratification the regression lines rotate in an orderly anticlockwise direction in response to the high calcite flux from the epilimnion in spring and the higher rate of mg2 replenishment than that of sr2 compensating for their loss in calcite the release of mg2 and sr2 from dissolving calcite in the hypolimnion at an mg sr ratio 7 5 eq eq much lower than that in the surrounding water 160 eq eq lends additional support to the anticlockwise rotation reversal of rotation occurs in summer when calcite crystallization and the freshwater supply slow down and brackish and saline water sources take control over the mg sr ratio in the lake subsequent turnover and mixing of the lake in winter reset the mg ca and sr ca ratios to their original values before the next stratification

cl br ratios of lake kinneret pore water and associated springs abstract the cl br ratio wt wt of pore water in a lake having diverse saline inputs was used to distinguish among the influx of different water sources and estimate their relative contributions pore water concentration profiles obtained by a passive multi layer sampler from bottom sediments of lake kinneret israel depict cl br ratios that vary between 70 and 156 and are similar to ratios in nearby onshore springs hamei tiberias and fulya respectively the cl br ratio of the lake 135 is strongly influenced by the cl br fingerprint of fulya type water however the discharge of the known fulya springs can not provide the required br mass about 648 tons y to maintain the cl br ratio in the lake therefore diffusive and advective fluxes of pore water are additional important mechanisms by which br is added to lake water moreover it is demonstrated that a combination of fulya and hamei tiberias type waters 90 and 10 respectively can explain the cl br ratio of the lake the areal distribution of the cl br ratio in pore water may be the result of dilution of an ancient evaporated solution cl br 70 with fresh water from adjacent aquifers cl br 150 followed by mixing with a saline solution having a high cl br ratio cl br 300 the results of this work suggest that the cl br ratio is a sensitive tool for the study of other similar environments

chemical tracing of salinity sources in lake kinneret sea of galilee israel lake kinneret is a freshwater lake in northern israel that receives a major part of its salt input from unmonitored springs that discharge through the lake s bottom we attempt to characterize the nature of these springs by estimating their chemical composition while the springs around lake kinneret are subject to wide spatial and temporal variations in their ionic concentrations specific sodium na potassium magnesium mg strontium bromine and lithium to chlorine cl ion ratios are almost constant within individual springs and spring groups the radium cl ratio and the d 18 o cl relationship confirm the notion that the spring waters result from recent mixing between saline brines and freshwater available compositional data from past years along with new analyses of the lake and its known springs allow identification of the salinity source that causes the observed deficit in the lake s salt budget e g 91 93 chloride the relative contributions from these saline springs are different for different ions this contribution is highest for bromide 95 decreases to 84 for na and is less than 50 for mg two independent approaches have been used for balancing the salts in the lake and they are as follows 1 an annual mass balance between salt removal and supply of the different ions assuming a steady state lake and 2 simulation of the lake s evolution from 1964 the beginning of salt removal from the lake via the salinity diversion channel until the present both methods predict very similar ionic ratios for the yet unknown average saline spring s testifying to the reliability of both approaches the ionic ratios so obtained closely resemble fuliya 6 tabgha type waters excluding the tiberias and eastern shore springs as significant salt sources this inferred composition of the average unmonitored springs depends strongly on present day diversion of saline springs this diversion thus prevents their flow into the lake the different ionic ratios that identify the various spring groups reflect the respective compositions of the brine pockets that feed them our simulation also shows that the layered structure of lake kinneret enhanced the evolution rate of the lake after the implementation of the salt diversion program in 1964 lake kinneret lk lake tiberias or the sea of galilee is a lake of immense historical and religious significance it is also the only freshwater lake in israel and the main water reservoir for the national water carrier nwc the water supply system that transfers freshwater to central and southern israel about 30 of the country s water supply was pumped from lk in 1995 furthermore with the water shortage in the middle east becoming more and more acute lk is also a waterbody of great political significance the lake is monomictic it is stratified between mid march and december the mixing of a fully stratified to a fully mixed lake takes about 4 5 months though it is a flowthrough lake it is significantly saltier than the jordan river which is its major water source table 1 the composition

ra and th adsorption coefficients in lakes lake kinneret sea of galilee natural experiment the adsorption rate constants of ra and th were estimated from empirical data from a freshwater lake and its feeding saline springs we utilized the unique setting of lake kinneret sea of galilee northern israel in which most of the ra and th nuclides are introduced into the lake by saline springs with high 226 ra activities and a high 224 ra 228 ra ratio of 1 5 the mixing of the ra enriched saline waters and freshwater in the lake causes the 224 ra 228 ra ratio to drop down to 0 1 in the kinneret due to preferential adsorption of 228 th these conditions constitute a natural experiment for estimating adsorption rates we developed a simple mass balance model for the radionuclides in lake kinneret that accurately predicted the ra isotope ratios and the 226 ra activity in the lake the model is comprised of simultaneous equations one for each radionuclide the equations have one input term supply of radionuclides from the saline springs and three output terms adsorption on particles in the lake radioactive decay and outflow from the lake the redundancy in the analytical solutions to the mass balance equations for the relevant nuclides constrained the values of ra and th adsorption rate constants to a very narrow range our results indicate that the adsorption rate constant for ra is between 0 005 d 1 and 0 02 d 1 the rate constant for th is between 0 5 d 1 and 1 d 1 about fifty to a hundred times higher the estimated desorption rate coefficient for ra is about 50 100 times larger than its adsorption rate constant the mass balance equations show that the residence times of all ra isotopes 226 ra 228 ra 223 ra 224 ra and of 228 th in the lake are about 95 92 14 6 and 1 d respectively these residence

internal sources and sinks of water p n ca and cl in lake kinneret israel mass balance budgets linked among several materials are used to infer rates of processes affecting lake kinneret comparisons among budgets reveal the magnitudes of internal sources and sinks that cannot be directly inferred from individual budgets a water budget indicates that 180 x 1 o6 m3 of sublacustrine spring water plus ungauged surface flow enters the lake annually about a fifth the total inflow and two thirds as much water as is lost to evaporation this total ungauged inflow delivers about 90 000 t of cl yr i nine times the stream input ca input from total ungauged flow is about a third the stream input and the net internal ca sink in the system is sufficient to precipitate 60 000 t of caco yr i stream delivery of p mainly as particulate material is largely sequestered in the sediments 100 t yr i at least 1 100 t yr i of n primarily as n03 delivered by streams are apparently lost to denitrification while only 200 t yr 1 are sedimented cycling of n and p within the lake dominates over throughput in controlling standing stocks vertical mixing within the lake may play a dominating role in this cycling cycling of p in the lake can be regarded as closed a sediment water column turnover of materials with only minor hydrographic loss from the system by contrast n cycling is open with an important net loss to the atmosphere aquatic ecosystems for which hydrographic constraints are well defined provide an opportunity for mass balance analysis of reactive materials biogeochemical patterns deduced in well defined systems should have general application in this paper mass balance analyses are derived for water cl p n and ca in lake kinneret israel most mass balance analyses of lakes treat individual elemental budgets independently of one another we deliberately compare budgets to ask the following two questions what

geophysical time domain electromagnetic model delineation of a shallow brine beneath a freshwater lake the sea of galilee israel the sea of galilee is a freshwater lake into which saline water emerges through onshore and offshore springs and through flux from the lake s sediments the novel surface marine modification of the time domain electromagnetic method was used to map the spatial distribution of brines in the sediments below the lake results indicate that electrical resistivities of 1 0 and 0 5 ohm m are detected at depths of 10 m below the lake bottom in most of the lake area which are equivalent to 11 000 and 22 000 mgcl l respectively relatively fresh groundwater was detected beneath most of the shoreline faulting controls the vertical interfaces between saline and fresh groundwaters it is hypothesized that salt transport is dominated by molecular diffusion in the central part of the lake and by advection from regional aquifers in the margins

the geochemistry of groundwater resources in the jordan valley the impact of the rift valley brines the chemical composition of groundwater in the jordan valley along the section between the sea of galilee and the dead sea is investigated in order to evaluate the origin of the groundwater resources and in particular to elucidate the role of deep brines on the chemical composition of the regional groundwater resources in the jordan valley samples were collected from shallow groundwater in research boreholes on two sites in the northern and southern parts of the jordan valley adjacent to the jordan river data is also compiled from previous published studies geochemical data e g br cl na cl and so4 cl ratios and b o sr and s isotopic compositions are used to define groundwater groups to map their distribution in the jordan valley and to evaluate their origin the combined geochemical tools enabled the delineation of three major sources of solutes that differentially affect the quality of groundwater in the jordan valley 1 flow and mixing with hypersaline brines with high br cl 2 10 3 and low na cl 0 8 ratios 2 dissolution of highly soluble salts e g halite gypsum in the host sediments resulting in typically lower br cl signal 2 10 3 and 3 recharge of anthropogenic effluents primarily derived from evaporated agricultural return flow that has interacted e g base exchange reactions with the overlying soil it is shown that shallow saline groundwaters influenced by brine mixing exhibit a north south variation in their br cl and na cl ratios this chemical trend was observed also in hypersaline brines in the jordan valley which suggests a local mixing process between the water bodies

evidence for stratigraphically controlled paleogeotherms in the illinois basin based on vitrinite reflectance analysis implications for interpreting coal rank anomalies coal rank reflects the temperature of coalification with higher rank coal forming at higher temperatures if the temperature of coalification depended only on the earth s geothermal gradient then the maximum rank of coal in a sedimentary basin should be directly proportional to the thickness of strata above the coal this association does not occur in the illinois basin a continental interior basin in the midwestern united states where the overall coal rank observed is higher than can be explained by past burial depth alone recognition of this anomaly has led many authors to suggest that hot groundwater flowing from south to north during a paleozoic basin scale groundwater migration event increased coal rank we analyzed vitrinite reflectance formula 1 a measure of rank as a function of depth in wells across the basin to determine how paleogeotherms representing variation in temperature with depth change with location our results show that the basin can be divided into three zones 1 in the southern zone the paleogeotherm varies irregularly with depth in strata above the sub absaroka unconformity the contact separating pennsylvanian and mississippian strata 2 in the central zone the paleogeotherm displays a distinct inflection at the unconformity for the rate of increase in formula 2 with depth is greater above the unconformity than below the unconformity and 3 the observed inflection in the paleogeotherm dies out northward until in the northern zone the paleogeotherm has the same slope both above and below the unconformity we propose that the inflection in the paleogeotherm of the central zone indicates that the hot groundwater responsible for causing an increase in coal rank flowed through a high permeability zone just below the sub absaroka unconformity this flow which advected heat into pennsylvanian strata above cooled as it moved northward so it did not influence the paleogeotherm in the northern zone preliminary studies of vein paragenesis stable isotope composition and fluid inclusions as well as computer modeling of flow related heat advection support this proposal 1 embed mml math 1 gif 2 embed mml math 2 gif

preservation of organic matter and alteration of its carbon and nitrogen isotope composition during simulated and in situ early sedimentary diagenesis abstract the carbon and nitrogen isotope composition of organic matter has been widely used to trace biogeochemical processes in marine and lacustrine environments in order to reconstruct past environmental changes from sedimentary organic matter it is crucial to consider potential alteration of the primary isotopic signal by bacterial degradation in the water column and during early diagenesis in the sediments in a series of oxic and anoxic incubation experiments we examined the fate of organic matter and the alteration of its carbon and nitrogen isotopic composition during microbial degradation the decomposition rates determined with a double exponential decay model show that the more reactive fraction of organic matter degrades at similar rates under oxic and anoxic conditions however under oxic conditions the proportion of organic matter resistent to degradation is much lower than under anoxic conditions within three months of incubation the 13c of bulk organic matter decreased by 1 6 with respect to the initial value the depletion can be attributed to the selective preservation of 13c depleted organic compounds during anoxic decay the 15n values continuously decreased to about 3 below the initial value the decrease probably results from bacterial growth adding 15n depleted biomass to the residual material in the oxic experiment 15n values increased by more then 3 before decreasing to a value indistinguishable from the initial isotopic composition the dissimilarity between oxic and anoxic conditions may be attributed to differences in the type timing and degree of microbial activity and preferential degradation in agreement with the anoxic incubation experiments sediments from eutrophic lake lugano are on average depleted in 13c 1 5 and 15n 1 2 with respect to sinking particulate organic matter collected during a long term sediment trap study

transient salt transport modeling of shallow brine beneath a freshwater lake the sea of galilee israel during a lake highstand phase in the late pleistocene the former saline lake lisan covered the topographic depression of kinarot basin currently occupied by the freshwater lake sea of galilee it was hypothesized that during this period the dense saline waters of lake lisan percolated into the sediment the recession of the saline lake from the basin and the rapid formation of a freshwater lake triggered solute transport from the sediment into the lake a one dimensional numerical model of solute transport that considers sediment compaction was developed to simulate chloride transport from the sediment into the lake simulation results were compared with measured chloride concentration profiles in sediment cores on the basis of a sensitivity analysis results are in agreement with the hypothesis that lake lisan solutes are currently discharged into the sea of galilee the calculated upward water velocity in the sediment ranges between 9