advances in marine chemistry 1979 1982 these four years saw advances in many areas further developments in sampling and analytical techniques have opened new avenues of exploration for trace elements and particulate matter the impact of the geosecs expedition was further felt in the field of marine chemistry as the results were still being published a major field effort occurred as a follow on to the geosecs work tto and intensive sampling was performed in the newly discovered submarine hydrothermal vent fields an important and unresolved controversy has arisen regarding the ability to measure preformed co2 in the seawater system in many respects the field of marine chemistry appears to be gaining a momentum spurred by both improvements in analytic techniques and an increasing social and economic relevance

geochemistry and deposition of 7be in river estuarine and coastal waters the atmospheric flux of cosmogenic 7be 53 3 day half life and the mode of 7be deposition in river estuarine and coastal environments have been examined the atmospheric flux of 7be commonly supports inventories ranging from 1 0 to 2 0 pci cm2 1 pci 0 037 bq beryllium 7 concentrations in water phase samples collected across salinity gradients in several estuaries along the eastern coastline of the united states range from 0 03 to 0 53 pci l and primarily reflect variations in 7be supply and sorption kinetics the major process controlling the concentration of 7be on estuarine suspended particles appears to be the length of time that these particles remain in the water column field particle to water distribution coefficients for 7be have a median value of about 4 104 but range over an order of magnitude reflecting short term variations in 7be input particle dynamics and particulate iron content rather than equilibrium sorption desorption responses to changes in water salinity or particle type residence times of 7be in the water column range from a few days in estuarine areas of rapid fine particle deposition to several weeks in high energy environments where pronounced sediment resuspension reintroduces deposited 7be back into the water column inventories of 7be in sediments range from nondetectable to 3 3 pci cm2 with the highest inventories in areas where fine particles are accumulating rapidly such sites are also major repositories for other particle reactive substances a 7be budget for the james estuary indicates that less than 5 of the expected 7be input is in the water column and that the short term estuarine trapping efficiency for atmospherically derived 7be is somewhere between 50 and 100

mount mazama eruption calendrical age verified and atmospheric impact assessed geochemical identification of mount mazama ash in the greenland ice sheet project 2 gisp2 ice core gives a calendrical age of 7627 150 cal yr b p 5677 150 b c for the eruption thus providing a more accurate early holocene stratigraphic time line than previously available the gisp2 record of volcanically derived sulfate suggests a total stratospheric aerosol loading between 88 and 224 mt spread over an 6 yr period following the eruption of mount mazama taking into account the likelihood of some tropospheric aerosol transport to greenland realistic estimates of the resulting atmospheric optical depth range from 0 6 to 1 5 these values may have produced a temperature depression of 0 6 to 0 7 c at mid to high northern latitudes for 1 3 yr after the eruption these results indicate that the 5677 b c eruption of mount mazama was one of the most climatically significant volcanic events of the holocene in the northern hemisphere we also calculate a maximum stratospheric cl release of 8 1 mt by the eruption which may have led to substantial stratospheric ozone depletion

interpretation of charcoal morphotypes in sediments from ferry lake wisconsin usa do different plant fuel sources produce distinctive charcoal morphotypes we describe five common charcoal morphotypes observed in late holocene lake sediments from northern wisconsin and compare them with charcoal produced by burning modern plant material our experiments show that grass cuticle conifer wood and leaves of some broadleaved taxa all produce recognizable charcoal types that are preserved in sediments we use the identification of charcoal morphotypes to enhance our interpretation of a previously published charcoal record from ferry lake wisconsin the occurrence of the different charcoal morphotypes changed as the vegetation and fire regimes changed over the past 2300 yr charred grass cuticle was more common before 1300 cal yr bp when small charcoal peaks were frequent and the pollen assemblage suggests that an open oak savanna surrounded the lake charcoal with bordered pits produced from burned conifer wood was more common after 1300 cal yr bp when red jack pine pollen increased and the frequency of charcoal peaks decreased suggesting a switch from a sur

late quaternary vegetation near battle ground lake southern puget trough washington pollen and plant macrofossil records from battle ground lake along with published data are used to reconstruct the late quaternary vegetation history of the nonglaciated southern puget trough coinciding with the end of the evans creek stade circa 20 000 17 000 yr b p of fraser glaciation gramineae artemisia herbs and picea cf engelmannii grew in a parkland tundra around battle ground this assemblage recorded throughout the southern puget trough implies cold relatively dry conditions similar to subalpine environments east of the cascade range the presence of pseudotsuga picea sitchensis and alnus rubra as macrofossils suggests a slight interstadial warming between 17 000 and 15 000 yr b p cool humid conditions prevailed during the vashon stade when south of the cordilleran ice sheet open forest or parkland featured mesophytic subalpine taxa at battle ground lake temperate conifers were part of forest communities circa 11 200 yr b p but elsewhere they were present as early as 12 500 yr b p from 10 000 to 4500 yr b p pseudotsuga quercus savannah spread into the battle ground area offering evidence for summer drought more severe than today pseudotsuga and thuja forest was established in the late holocene with the introduction of the modern humid climate consideration of all the pollen data from the southern puget trough and the available radiometric chronology suggests that postglacial migration of most lowland conifers into the puget trough was rapid and not necessarily from southern refugia

an 11 000 year long record of fire and vegetation history at beaver lake oregon central willamette valley high resolution macroscopic charcoal and pollen analysis were used to reconstruct an 11 000 year long record of fire and vegetation history from beaver lake oregon the first complete holocene paleoecological record from the floor of the willamette valley in the early holocene ca 11 000e7500 calendar years before present cal yr bp warmer drier summers than at present led to the establishment of xeric woodland of quercus corylus and pseudotsuga near the site disturbances i e floods fires were common at this time and as a result alnus rubra grew nearby high fire frequency occurred in the early holocene from ca 11 200e9300 cal yr bp riparian forest and wet prairie developed in the middle holocene ca 7500 cal yr bp likely the result of a decrease in the frequency of flooding and a shift to effectively cooler wetter conditions than before the vegetation at beaver lake remained generally unchanged into the late holocene from 4000 cal yr bp to present with the exception of land clearance associated with euro american settlement of the valley ca 160 cal yr bp middle to late holocene increases in fire frequency coupled with abrupt shifts in fire episode magnitude and charcoal composition likely indicate the influence anthropogenic burning near the site the paleoecological record from beaver lake and in particular the general increase in fire frequency over the last 8500 years differs significantly from other low elevation sites in the pacific northwest which suggests that local controls e g shifts in vegetation structure intensification of human land use rather than regional climatic controls more strongly influenced its environmental history

7be in sargasso sea and long island sound waters 7be was measured in surface waters of the western sargasso sea and long island sound the calculated standing crop in the sargasso sea is equal to that predicted from precipitation collectors long island sound is deficient in 7be virtually none exists in the water column and less than half of the expected standing crop has been reported for the sediments a possible sink for the missing 7be may be the salt marshes or tidal mud flats ringing long island sound

rapid oxygen utilization in the ocean twilight zone assessed with the cosmogenic isotope 7be 1 the rate of oxygen utilization beneath the sunlit surface ocean provides a measure of the export rate of biologically produced carbon to the deep sea and its variation with depth suggests where remineralization of that carbon occurs the latter consideration is relevant to the efficiency of carbon sequestration in deep water however accurate characterization of this process particularly within 200 m of the euphotic zone where carbon utilization is most intense has been difficult owing to limitations of techniques applied to these shallow depths here a novel approach utilizing the cosmogenic isotope 7be indicates that at a site in the subtropical north atlantic 65 of sinking carbon is remineralized within 200 m of the ocean s surface and is thus readily available for return to the atmosphere the corresponding oxygen utilization rates are greater than would be suggested by the attenuation with depth of organic matter measured by shallow sediment traps

the geochemical cycle of 9be a reconnaissance an initial survey has been made of the geochemistry of 9be in natural waters with a view to utilizing the isotope with the cosmogenic species 10be t1 2 1 5 m y in geochronological studies of sedimentary accumulation the mobility of9be in continental waters is a strong function of ph with acid streams ph 6 being strongly enriched as compared to alkaline carbonate rivers large scale scavenging of beryllium occurs in the estuaries of rivers containing more than about 200 pm of the element in alkaline systems of lower concentration the element appears to behave conservatively the net flux of beryllium to the ocean is estimated as that equivalent to an average effective river concentration of about 150 pm beryllium is strongly enriched in ridge crest hydrothermal solutions over ambient seawater the flux is approximately 70 of that from the continents the deep water concentrations of 9be vary by only 20 between the north atlantic and north pacific demonstrating that the chemical saltation produced by scavenging from the deep water column and release from the sediments predominates over simple advective concentration along flow lines isotopic homogenization of 10be and 9be is probably achieved in the ocean the situation in continental waters appears much less promising

postglacial vegetation and climate of the cascade range central oregon abstract pollen data from two sites provide information on the postglacial vegetation and climate history of the cascade range indian prairie in the western cascade range was colonized by subalpine forests of pinus picea and tsuga and open meadows prior to ca 12 400 14 c yr b p the treeline lay 500 to 1000 m below its modern elevation and conditions were cooler than at present from ca 12 400 to ca 9950 14 c yr b p abies became important and the forest resembled that presently found at middle elevations in the western cascade range the pollen record implies a rise in treeline and warmer conditions than before from ca 10 000 to 4000 4500 14 c yr b p conditions that were warmer and effectively drier than today led to the establishment of a closed forest composed of pseudotsuga abies and at lower elevations quercus and corylus during this period gold lake bog in the high cascades was surrounded by closed forest of pinus and abies the early holocene pollen assemblages at both indian prairie and gold lake bog lack modern analogues and it is likely that greater than present summer radiation fostered unique climatic conditions and vegetation associations at middle and high elevations in the late holocene beginning ca 4000 4500 14 c yr b p cooler and more humid conditions prevailed and the modern vegetation was established a comparison of these sites with others in the pacific northwest suggests that major patterns of vegetational change at individual sites were a response to large scale changes in the climate system that affected the entire region

field laboratory and modeling investigation of the skin effect at wells with slotted casing boise hydrogeophysical research site understanding and quantification of wellbore skin improves our ability to accurately measure or estimate hydrologic parameters with tests at wells such as pumping tests flowmeter tests and slug tests this paper presents observations and results from a series of field laboratory and modeling tests which together explain the source of wellbore skin at wells at a research wellfield and which support estimation of skin thickness ds and skin hydraulic conductivity ks positive wellbore skin effects were recognized at wells in the shallow unconfined coarse grained fluvial aquifer at the boise hydrogeophysical research site bhrs well development efforts at the bhrs removed residual drilling fines but only marginally reduced the skin effect likely causes for the remaining wellbore skin effect were examined partial clogging of screen slots with sand is consistent with field observations and can account for the magnitude of wellbore skin effect observed we then use the wtaq code barlow and moench 1999 with a redefinition of the term for delayed observation well response to include skin effects at observation wells in addition to pumping wells in order to analyze aquifer tests at the bhrs for average ks values at individual wells systematic differences in ks values are recognized in results at pumping ks q and observation ks obs wells larger values are seen at observation wells average ks obsz0 0023 cm s than pumping wells two possible causes are recognized for the occurrence of higher ks values at observation wells than pumping wells 1 flow diversion between aquifer layers on approach to a pumping well with positive skin and 2 larger portion offlow passing through lower k zones in the heterogeneous aquifer near the pumping well than the observation wells due to strongly radially convergent flow near the pumping well for the wellaquifer system at the bhrs modeling analyses of drawdown vs time at observation wells provide better ks estimates than those from pumping wells q 2005 elsevier b v all rights reserved

measurement of7be by accelerator mass spectrometry abstract we describe an accelerator mass spectrometry ams technique for measuring the cosmogenic isotope 7 be half life 53 2 days our detection limit of 10 4 atoms with this technique is 100 times lower than that obtained by counting the potential advantages of this increased sensitivity combined with ams measurements of 10 be half life 1 5 my in the same samples are discussed in the context of the application of 7 be 10 be as a time dependent tracer of various environmental transport processes

residence times of234th and7be in lake geneva the activities of two short lived natural radionuclides 234th and7be were measured in lake geneva water suspended solids and sediments in order to obtain their removal residence times in the lake four independent methods of estimation are presented and compared the calcuated residence times of234th and7be vary from 60 to 280 days and from 60 to 1100 days respectively depending on season and the method used in general 7be residence times are significantly longer than those of234th for both nuclides the removal residence times are significantly longer than their respective radioactive mean lives as a consequence the estimates based on their water column inventories are not as reliable as the estimates obtained from the measured fluxes of these nuclides into sediment traps estimates based on the bottom sediment inventories are similar in magnitude to those obtained from flux into sediment traps but occasionally are erroneous because of small scale sediment heterogeneity

upwelling and primary production during the u s geotraces east pacific zonal transect the 2013 u s geotraces eastern pacific zonal transect epzt traversed the highly productive peruvian coastal upwelling pcu region in this work the flux of nitrate into the euphotic zone is derived for stations within the pcu using a previously developed method whereby dilution of the water column 7be inventory by upwelled 7be free water provides a means to infer upwelling rates furthermore with knowledge of upwelling rates 7be profiles are used to constrain vertical diffusivity within the upper thermocline these transport terms are applied to nitrate profiles to estimate net community production between 79 w and 104 w along the epzt which includes the zone of active upwelling to the edge of the oligotrophic gyre with a simple one dimensional model the calculated upwelling rates were inversely related to mixed layer temperature and ranged from 0 to 3 0 m d results using a depth dependent upwelling rate with a component of horizontal advection are also described vertical diffusivities near the base of the euphotic zone were in the range 1 7 4 5 10 4 m2 s these values are compared to those generated by analysis of temperature profiles net community production averaged 15 mmol c m2 d for stations between 84 w and 104 w and was 134 mmol c m2 d for the furthest inshore station at 79 w which displayed the lowest sst and greatest rate of upwelling

hierarchical geostatistics and multifacies systems boise hydrogeophysical research site boise idaho 1 the geostatistical structure of a heterogeneous coarse fluvial aquifer is investigated with porosity data derived from neutron logs at a research well field boise hydrogeophysical research site or bhrs that was designed in part to support three dimensional geostatistical analysis of hydrologic and geophysical parameters recognizing that the coarse fluvial deposits include subdivisions units between bounding surfaces we adopt a hierarchical approach and examine the porosity geostatistics of the aquifer at three scales at the bhrs the saturated fluvial deposits as a whole maximum interwell spacing 80 m thickness 16 18 m are at hierarchical level 1 five subhorizontal units within these deposits four cobble dominated units and a channel sand can be traced across the central area of the bhrs and are at hierarchical level 2 and subunits patches or lenses in one of the level 2 units unit 4 are at hierarchical level 3 we use variography and porosity statistics to recognize nonstationarity at hierarchical level 1 and in one of the level 2 units unit 4 where the means and variances of porosity differences as a function of lag are not constant between distinct units and subunits respectively the geostatistical structure at level 1 is modeled with different horizontal and vertical structures that have different sills vertical sill greater than horizontal sill the difference in sills can be explained quantitatively by the summing of weighted sills from all individual units and combined units i e a given pair of different units where the weights are the proportions of data pairs contributing to the sills at each lag from the individual and combined units extension of this analysis leads to a weighted multistructure form of the variogram function whereby a global experimental variogram in a hierarchical system can be decomposed quantitatively into weighted component individual and combined unit or facies structures for any number of units or hierarchical levels such decomposition of the global horizontal variogram from the bhrs indicates that short range periodicity in that structure is due to both 1 combined unit structures associated with patches or lenses at hierarchical level 3 in unit 4 and 2 variations in thickness of unit 2 for hierarchical multifacies systems structure models fit to global horizontal and vertical experimental variograms may not be useful for subsequent stochastic modeling if the system on which the structure models are based is nonstationary

significance of porosity for stratigraphy and textural composition in subsurface coarse fluvial deposits boise hydrogeophysical research site recognition and quantitative characterization of subsurface stratigraphic units in coarse unconsolidated fluvial deposits are difficult because large grain size and the large scale of sedimentary structures make direct interpretation from core difficult or impossible in this paper we use porosity data from well logs and grain size distribution gsd data from core to investigate four pebble and cobble dominated units that have been identified in porosity logs in deposits at a research well field boise hydrogeophysical research site lacking direct observation at an appropriate scale questions about distribution of parameters and textural composition in these units are analyzed with statistical tests the four pebble and cobble dominated porosity stratigraphic units may be grouped into two types 1 units 1 and 3 have low porosity mean 0 17 0 18 and low porosity variance and 2 units 2 and 4 have higher porosity mean 0 23 0 24 and higher porosity variance based on gsd data core samples are subdivided into five lithotypes the five lithotypes occur in different proportions and have different vertical transition probability characteristics in the two types of units 1 units 1 and 3 have only framework gravel dominated lithotypes and have random vertical transition probability between these two lithotypes and 2 units 2 and 4 consist of both framework gravel dominated and sand or matrix dominated lithotypes and have structured vertical transition probability the two framework gravel dominated lithotypes occur in all four stratigraphic units but have distinctly lower porosity in units 1 and 3 i e tighter packing than in units 2 and 4 looser packing considering the repeated stratigraphic occurrence of and the statistical significance of differences between the two types of units both the individual unit distinctions and the two unit groupings appear to be valid it is reasonable to interpret that the observed packing differences associated with units 1 and 3 compared with units 2 and 4 are related to different sedimentary processes that produce different bedforms or grain fabrics perhaps under different bedload transport rates

analytical modeling of saturated zone head response to evapotranspiration and river stage fluctuations summary we investigate the response of the saturated zone unconfined aquifer to evapotranspiration et flux at ground surface we neglect fluid flow and storage in the unsaturated zone and treat et as a sinusoidal forcing function at the watertable the linearized kinematic condition is imposed at the watertable analytical solutions are developed for the case of flow in a domain of a semi infinite extent to simulate response in a domain bounded by a river and b infinite lateral extent to simulate the response in a domain with no river boundaries these solutions are fitted to observed groundwater head fluctuations recorded in observation wells at the boise hydrogeophysical research site in idaho and the larned research site in kansas estimates of the amplitude of the et flux aquifer hydraulic conductivity specific storage and specific yield are obtained and these compare well to published results from pumping tests conducted at the site the field exercise is used to explore the potential for using groundwater head fluctuations to estimate et and hydraulic parameters of unconfined aquifers

recognizing and modeling variable drawdown due to evapotranspiration in a semiarid riparian zone considering local differences in vegetation and distance from a river source 1 riparian zones in semiarid regions often exhibit high rates of evapotranspiration et in spite of low soil moisture content due to the presence of phreatophytic vegetation that is able to withdraw water from shallow aquifers this work seeks to better define the relationship between et the saturated zone and the river boundary by comparing observed water table drawdown records to analytically modeled drawdown in fully penetrating wells of an unconfined aquifer in response to daily et flux et at the boise hydrogeophysical research site bhrs a riparian zone in a temperate semiarid environment is calculated using a radiation based method to provide et values at four different wells with different vegetation densities analytically modeled drawdown response to et forcing shows that drawdown magnitude increases with increasing distance from the river edge even as the surficial et forcing remains constant this behavior is also observed in well hydrographs and shows the buffering effect that flow from the river has on drawdown in fully penetrating riparian wells in highly permeable unconfined aquifers relative contributions of river water to aquifer storage are calculated for et induced diurnal fluctuations of the water table at increasing distances from the river boundary failure to account for these spatial differences in drawdown related to the river source may explain some errors associated with estimating et from well hydrographs alone

flow to a well of finite diameter in a homogeneous anisotropic water table aquifer a laplace transform solution is presented for the problem of flow to a partially penetrating well of finite diameter in a slightly compressible water table aquifer the solution which allows for evaluation of both pumped well and observation piezometer data accounts for effects of well bore storage and skin and allows for the noninstantaneous release of water from the unsaturated zone for instantaneous release of water from the unsaturated zone the solution approaches the line source solution derived by neuman as the diameter of the pumped well approaches zero delayed piezometer response which is significant during times of rapidly changing hydraulic head is included in the theoretical treatment and shown to be an important factor in accurate evaluation of specific storage by means of a hypothetical field example it is demonstrated that evaluations of specific storage ss using classical line source solutions may yield values of ss that are overestimated by a factor of 100 or more depending upon the location of the observation piezometers and whether effects of delayed piezometer response are included in the analysis theoretical responses obtained with the proposed model are used to suggest methods for evaluating specific storage