rare earth elements in modern coral sands an environmental proxy the concentration rare earth elements and yttrium ree y were determined in coral sands from kavaratti island arabian sea india chondrite normalized ree y patterns show 1 high ree concentration particularly light ree lree enrichment 2 consistent negative ce anomaly 3 nearly chondritic y ho ratios all these features are consistent with the geochemistry of well oxygenated seawater with significant terrestrial contribution the seawater composition of nd yb ratio inferred from the coral record point to the dominance of lree more than the heavy ree hree the high terrestrial input rich in lree and property of adsorption scavenging processes of lree than that of hree may be the cause terrigenous contributions were detected on the basis of co occurring trace element concentrations sc hf and th and y ho ratio except for la the ree distribution coefficients kd ree s are between 100 and 300 kds are high comparing to the other elements in biogenic calcite which is attributed to detrital contamination during elemental incorporation this study may not reflect original seawater chemistry but it can be a good proxy to indicate proximity of corals to terrigenous input sources

phosphorus cycling in sediments of the bohai and yellow seas using a box sampler surface and core sediment samples were collected from the bohai and yellow seas in 1998 1999 the sediments were sequentially extracted to determine six phosphorus fractions and non sequentially extracted for total p tp and inorganic p ip where the difference between tp and ip was assumed to be organic p op it was found that more than 70 of the total p is inorganic p the concentrations of phosphorus were high near the river mouth reflecting the influence from the huanghe and changjiang sediment loads the phosphorus levels in the bohai sea are higher than those in the yellow sea which is related to the sediment sources and distribution of chlorophyll a in these areas concentrations of tp in the bohai and yellow seas are comparable to the other worldwide coastal areas among the six forms of phosphorus phosphorus distribution ranges were 0 8 2 for loosely sorbed p 3 10 for iron bound inorganic p 4 19 for leachable organic p 3 15 for authigenic apatite 35 66 for detrital apatite and 14 36 for refractory organic p potentially bioavailable phosphorus accounts for a small amount of tp while phosphorus load associated with eroded soil may be larger than the anthropogenic load the regeneration of dissolved p from sediments is a slow process which could play a role in maintaining low phosphate levels in the seas most of the phosphorus was regenerated in a water column and almost all of the remaining phosphorus was buried in the sediments after its accumulation the high values of p burial efficiencies in the study areas were related to low benthic phosphate flux which is due to the high percent of detrital apatite that is not bioavailable and the high sediment accumulation rate

a multiproxy approach to reconstructing sea surface conditions using coral skeleton geochemistry 1 we use elemental ratio mg ca sr ca u ca and ba ca and oxygen isotope data from a porites lutea coral head collected from offshore amedee island new caledonia 22 29 s 166 28 e to assess the degree to which changes in these geochemical variables reflect variations in sea surface conditions we have assessed the robustness of each geochemical proxy by comparing 25 years 1992 1968 of monthly geochemical variations with a local record of sea surface temperature sst and with the appropriate 1 by 1 grid box from a global gridded sst data set we conclude from our comparison that the most consistent proxies of monthly sst variations at this site are 18o r2 0 84 p 0001 and sr ca r2 0 84 p 0001 the fidelity of the coral based sr ca sst proxy was assessed via calibration verification exercises at new caledonia and rarotonga the paleoclimate accuracy of the coral sr ca sst technique is judged to be robust and the precision of the technique is estimated to be 0 3 0 5 2 based on the calibration verification exercise in contrast monthly variations in mg ca and u ca ratios are only moderately correlated with monthly sst variations r2 0 55 p 0001 for mg ca and r2 0 47 p 0001 the strength of the correlation between sst and mg ca and u ca varies as a function of time suggesting that variations in these ratios are not a simple function of sst variations this variability in goodness of fit between u ca sst and mg ca sst may ultimately limit the use of these ratios as coral paleothermometers averaging or stacking individual proxy sst records sr ca mg ca and u ca to generate a composite proxy sst record does not necessarily improve the proxy record if the signal to noise ratio in each proxy is highly variable for example stacking of sr ca mg ca u ca records at new caledonia produces a proxy sst time series that has greater standard error than the individual sr ca sst time series cf ordinary least squares standard error of 1 16 c versus 0 86 c ba ca variations have little correlation with sst sr ca mg ca or u ca variations at new caledonia in conclusion variations in oxygen isotopic composition of seawater calculated by removing the sr ca based temperature component of the 18o signal agree reasonably well with observed variations in sea surface salinity especially at the interannual timescale

global climatic anomalies associated with extremes in the southern oscillation abstract composite temperature and precipitation anomalies during various stages of an event in the southern oscillation so have been computed for several hundred stations across the globe large regions of coherent significant signals are shown to exist for both extremes of the so with warm event signals generally opposite to those during cold events in addition during the year preceding the development of an event in the so year 1 climatic anomalies tend to be opposite to those during the following year year 0 this confirms that the biennial tendency of the so over the pacific indian ocean sectors is also present in more remote regions with climatic signals related to the so many of the signals are consistent enough from event to event to be useful for extended range forecasting purposes

climatically controlled marker layers in santa barbara basin sediments and fine scale core to core correlation varved sediments with annual layering can provide a detailed history of environmental conditions of marginal ocean basins and of lakes to reconstruct this history requires fine scale correlation and correct age assignment in the santa barbara basin a combination of x radiography water content profiles and microfossil stratigraphy yields correlations of the desired resolution x radiography permits identification of individual layers 1 2 mm thick that differ in porosity or pore water content and hence x ray absorption microfossils and sedimentological parameters provide the clues to the presence for el nino years e g in a d 1984 1959 and 1942 varves allowing the tie in to absolute years within this century el nino layers once identified are readily recognized on the radiographs and within the porosity profiles counting of laminae in x radiographs and core to core correlation via water content then allow establishing age scales for other cores a prominent shell layer in the first half of the 19th century is dated at a d 1838 this event macoma i is of supraregional significance

a multiproxy record of terrestrial inputs to the coastal ocean using minor and trace elements ba ca mn ca y ca and carbon isotopes δ13c δ14c in a nearshore coral from puerto rico 1 small mountainous rivers smrs despite their disproportionate size relative to larger rivers may contribute as much as one third of the total terrigenous material exported to the coastal ocean corals growing near the mouths of tropical smrs have the potential to provide records of terrigenous material fluxes because they are long lived and elemental and isotope signatures within their skeletons are useful proxies of palaeoceanographic variability here a 56 year record of coral skeletal ba ca mn ca y ca 13c and 14c measurements is presented from a montastraea faveolata colony growing 1 km from the mouth of an smr in eastern puerto rico coral ba ca was coherent with river discharge and coral skeletal 13c at annual periodicity corresponding to synchronous depletions of both 13c and 14c in the coral skeleton and mn ca and y ca were not coherent with river discharge at annual periodicity coherence between river discharge and ba ca and the concurrent timing of increases in ba ca with decreases in 13c and 14c indicate that river discharge is simultaneously recorded by all three geochemical tracers a reconstruction of rio fajardo discharge is presented for a period in which no instrumental discharge records exists shows good fidelity with the timing of increased discharge during the wet season thus coral based multiple proxy records can be valuable tools for reconstructing the timing and variability of smr discharge to the coastal ocean such records are critical to understanding changes in material fluxes and biogeochemical cycles in coastal environments due to land use and climate change

surface ocean variability at galapagos from 1936 1982 calibration of geochemical tracers in corals a variety of geochemical tracers has been developed in reef corals as a means of reconstructing the natural variability of the tropical surface ocean over wide ranging time frames the purpose of this paper is to calibrate the performance of five of these tracers in a modern coral colony over an extended period a 47 year growth interval 1936 1982 in a colony of pavona clavus taken from san cristobal island galapagos islands was sectioned into 187 quarterly intervals and analyzed for 18o 13o ba ca cd ca and mn ca the resulting time series are compared with eastern pacific sea surface temperatures one of few instrumental data bases available for calibration over this time period linear least squares regressions of four of the tracers 18o 13o ba ca cd ca against peruvian sst show highly significant correlations p 0 0001 over the annual biennial and enso 3 8 years frequency bands cross spectral comparisons show even stronger coherency with sst frequently accounting for 70 80 of the variance in these tracers these results as well as the phase relationships determined from the spectral analyses suggest that the coupling between sst and 18o and the nutrientlike tracers ba and cd is controlled principally by seasonal upwelling cycles and interannual interruptions of these cycles brought about by el nino and anti el nino phenomena an inverse relationship between sst and 13c has its primary origins in the co occurrence of the warm sst phase with high light levels during the first half of the calendar year the association with sunlight derives from the photosynthetic response of algal symbionts which results in fractionation of light and heavy carbon isotopes between soft tissues and caco3 skeleton the fifth tracer the transition metal mn exhibits poorer correlations against both sst and the other tracers slight shifts in phasing of the historical mn ca annual cycle suggest that the general water column distribution of this tracer which is the reverse of a nutrient may not be stable the erratic behavior of mn illustrates how complex hydrography near galapagos may influence tracers with diverse source signatures

decadal variations in trace metal concentrations on a coral reef evidence from a 159 year record of mn cu and v in a porites coral from the northern south china sea geochemical cycles of trace metals are important influences on the composition and function of the marine ecosystem although spatial distributions of most trace metals have now been determined in at least some parts of the oceans temporal variations have barely been studied on account of data limitations in this paper we report on a 159 year record of trace metal concentrations from a porites coral from the northern south china sea scs and discuss how oceanic and climatic processes control variations in mn cu and v concentrations in this region our results show that trace metal concentrations in the coral skeleton demonstrate decadal to interdecadal fluctuations and that their variations are controlled by different mechanisms the input of mn to reef water is partly controlled by the pacific decadal oscillation pdo which controls precipitation and river runoff surface water concentrations of the nutrient like element cu are controlled by summer upwelling to the east of hainan island the concentrations of v show complex interrelationships and are linked to riverine input prior to the 1990 and to upwelling after the 1990 our results imply that in the northern scs ocean atmosphere climate fluctuations such as the pdo and the east asian summer monsoon easm are important factors that influence long term variability of mn cu and v concentrations in seawater by controlling precipitation related river runoff and the strength of upwelling systems

a chemical indicator of trade wind reversal in corals from the western tropical pacific historical levels of manganese have been measured in the annual rings of a reef coral from tarawa atoll 1 30 n 173 e in order to assess the temporal variability of this trace element in surface waters of the western tropical pacific seasonal variability associated with vertical mixing is not apparent as is the case in the eastern pacific however mn ca ratios are highly perturbed during three el nino southern oscillation enso events 1965 1972 1976 that occurred within the growth period 1960 1977 for approximately 6 months during each of these events mn ca ratios increase by 50 80 from a background of 27 nmol mn mol ca these features co occur with negative 18o pulses recorded in the same coral which result from anomalously abundant rainfall wet deposition of mn however does not appear to be an adequate source to account for the inferred surface ocean enrichments the most plausible explanation has to do with the transient appearance of westerly winds along the equator during enso periods particularly vigorous westerly wind bursts sometimes averaging 10 m sec or more over 16 hours during the aforementioned years may have generated wind waves of sufficient strength to create an aura of particulate and diagenetically remobilized mn from within the shallow westward facing lagoon of tarawa this interpretation is supported by relatively high mn concentrations measured in pore waters of tarawa lagoon sediments the results suggest a useful new chemical tracer of historical enso conditions in the western pacific basin

mg ca sr ca and u ca ratios of a porites coral from sanya bay hainan island south china sea and their relationships to sea surface temperature high resolution mg ca sr ca and u ca ratios are reported in the skeleton of porites sp collected from sanya bay on the south coast of the hainan island china using inductively coupled plasma mass spectrometry combined with isotope dilution technique icp ms id the coralline mg ca ratios covary with sea surface temperatures sst for the 10 year interval giving the relationship between mg ca and sst as t degrees c 14 13 0 31 8 846 0 068 x 10 3 mg ca with the mean square weighted deviation mswd of 9 7 using this equation we are able to reconstruct sst record with a precision better than 0 5 degrees c several sr ca and u ca ratios show poor linear relationships with the measured sst this study indicates that the growth rates of the coral do not significantly affect coralline mg ca sr ca and u ca ratios however the high meteoric precipitation in this area which may cause a heavy run off from the island may change seawater sr ca and u ca ratios and ruin the relationships between coralline sr ca or u ca ratios and sst this implies that in coastal areas like hainan coralline mg ca ratios are valid for reconstructing the sst records but sr ca and u ca ratios may be suspected c 2000 elsevier science b v all rights reserved

cadmium chemical tracer of deepwater paleoceanography the oceanic distribution of cadmium resembles that of phosphorus because the cadmium content of foraminiferal shells is governed by the cadmium content of seawater planktonic and benthic fossil shells can be used to infer nutrient distributions within ancient oceans empirical studies demonstrate that cadmium in benthic foraminiferal shells is related to the bottom water composition through a proportionality constant d 2 9 this constant is the same for each of the species studied cibicidoides wuellerstorfi cibicidoides kullenbergi nuttallides umbonifera and uvigerina spp downcore cadmium data from high quality pacific and atlantic sediment cores suggest that the cadmium inventory of the ocean did not change significantly between the most recent glacial maximum and the present hence changes in the cadmium content of fossils at a site directly reflect changes in nutrient distributions due to altered oceanic circulation patterns studies of cadmium in pleistocene sediments show that deep ocean circulation patterns were significantly different during the most recent glacial maximum in the western north atlantic ocean the nutrient content of waters from 2500 to 3500 m was twice as high during glacials as during interglacial periods signifying an increase in the proportion of waters of antarctic origin in this depth interval and a decrease but not a cessation in the flux of north atlantic deep waters through this depth range below 3500 m the nutrient increase was greater indicating a higher proportion of antarctic bottom water above 2500 m the nutrient content was lower during glacial periods than it has been during interglacial times the cd content of high latitude north atlantic and southern ocean surface waters does not show a significant glacial interglacial change which argues against theories for changes atmospheric carbon dioxide that require changes in high latitude nutrient concentrations

observations of annual and el nino thermal and flow variations at 0 110 w and 0 95 w during 1980 1985 moored measurements of the surface wind and of the current and temperature fields within the uppermost 250 m were recorded from march 1980 to september 1985 at 0 110 w and from july 1981 to november 1983 at 0 95 w at these sites the annual mean thicknesses of the equatorial undercurrent euc and of the surface portion of the south equatorial current sec were about 200 m and 20 m respectively the annual mean euc core speed was 0 9 m s 1 annual cycles of temperature and zonal current at 110 w were most distinctive near the surface at nominal depths of 15 m and 47 5 m the average annual amplitudes were 1 5 c and 0 5 m s 1 at about 100 m the annual amplitudes were about 0 5 c and 0 10 m s 1 at 15 m the annual mean zonal current was 0 05 m s 1 which was not representative of the monthly mean zonal current in april the monthly mean direction was eastward and in october it was westward with speeds of about 0 5 m s 1 in both months warmer water occurred in april and colder water in october the direction of the zonal wind component was westward throughout the year and the annual amplitude of the zonal wind was only about 2 5 times larger than that of the zonal current the average amplitude of the annual cycle of the meridional current component was less than 0 05 m s 1 and not distinguishable from year to year monthly mean variations monthly mean anomalous or el nino currents at 110 w were defined as the difference between the observations and the annual cycle during the august december 1982 onset phase of el nino the strength of the normally westward flowing near surface sec was greatly reduced to near zero speed by an el nino eastward flowing zonal current of about 0 3 m s 1 the largest vertically averaged 15 250 m zonal current anomaly 0 5 m s 1 occurred in january and february 1983 and represented a substantial decrease in the eastward transport of the euc causing a disappearance of the undercurrent the duration of the euc disappearance was longer at 95 w than at 110 w a surface intensified eastward jet with a maximum daily speed of 1 75 m s 1 at 15 m occurred in may 1983 at 110 w but not at 95 w a massive redistribution of heat throughout the mixed layer and thermocline was associated with the 1982 1983 el nino beginning in august 1982 the thermocline at 110 w and 95 w sank 100 m reaching its maximum depth in december 1982 temperatures at 100 m and 150 m which normally were about 15 c and 14 c reached 27 5 c and 22 5 c the time rate of change of the 15 to 200 m heat content was 500 w m 2 during the august december 1982 warming phase and 460 w m 2 during the january february 1983 subsurface cooling phase the euc disappeared during the subsurface cooling phase a second less intensive mixed layer deepening occurred in may 1983 at 95 w but not at 110 w

the geochemistry of potassic lavas from vulsini central italy and implications for mantle enrichment processes beneath the roman region major and trace element and 143nd 144nd 0 51209 0 51216 and 87sr 86sr 0 70879 0 71105 isotope analyses are presented on a representative group of lavas from the vulsini district of the roman magmatic province three distinct series are identified the high k and low k series are similar to those described from other italian volcanoes while the third is represented by a group of relative ly undifferentiated leucite basanites which are thought to be near primary mantle melts major and trace element variations within the high k series are consistent with fractional crystallisation from a parental magma similar to the most magnesian leucitites crustal contamination resulted in an increase in 87sr 86sr with increasing fractionation but it was superimposed on magmas which had already inherited a range of incompatible element and isotope ratios from enrichment processes in the sub continental mantle these are reviewed using the available results from vulsini roccamonfina and ernici transition element abundances and ta yb ratios indicate that the pre enrichment mantle was similar to that of e type morb and that these elements were not mobilised by the enrichment process mixing calculations suggest that three components were involved in the enrichment process mantle comparable with the source of morb and two other components rich in trace elements one the low k component had high sr nd th ta and ba nb and no europium anomaly while the second had lower sr nd a negative europium anomaly and very high th ta it was also characterised by low nb ba and high rb ba ratios similar to those reported from phlogopite rich peridotite xenoliths the trace element enrichment processes are therefore thought to have occurred in the mantle wedge above a subduction zone with the trace element characteristics of the high k end member reflecting the subduction of sediments and the stabilisation of mantle phlogopite

geochemistry based coral palaeoclimate studies and the potential of non traditional non massive porites corals recent developments and future progression understanding the natural variability of the earth s climate system and accurately identifying potential anthropogenic influences requires long term geographically distributed records of key climate indicators such as temperature and precipitation that extend prior to the last 400 years of the holocene reef corals provide an excellent source of high resolution climate records and importantly represent the tropical marine environment where palaeoclimate data are urgently required recent decades have seen significant improvement in our understanding of coral biomineralisation the associated uptake of geochemical proxies and methods of identifying and understanding the effects of both early and late post depositional diagenetic alteration these processes all have significant implications for interpreting geochemical proxies relevant to palaeoclimatic reconstructions this paper reviews the current state of the art in terms of coral based palaeoclimate reconstructions and highlights a key remaining problem the majority of coral based palaeoclimate research has been derived from massive colonies of porites however massive porites are not globally abundant and may not provide material of a particular age of interest in those regions where they are present therefore there is great potential for alternate coral genera to act as complimentary climate archives while it remains critical to consider five key factors vital effects differential growth morphologies geochemical heterogeneity in the skeletal ultrastructure transfer equation selection and diagenetic screening of skeletal material in order to allow the highest level of accuracy in coral palaeoclimate reconstructions it is also important to develop alternate taxa for palaeoclimate studies in regions where porites colonies are absent or rare currently as many as nine genera other than porites have proven at least limited utility in palaeothermometry most of which are found in the atlantic caribbean region where massive porites do not exist even branching taxa such as acropora have significant potential to preserve environmental archives increasing this capability will greatly expand the number of potential geochemical archives available for longer term temporal records of palaeoclimate

paleoclimatic inference from stable isotope profiles of accretionary biogenic hardparts a quantitative approach to the evaluation of incomplete data abstract variation in 18o of invertebrate and vertebrate skeletons has been widely employed to estimate annual means and seasonal ranges of temperature from many geologic settings among incertitudes encountered in employing this approach is the influence of unconstrained noise in environmental signals cessation of hardpart accretion during reproduction and or seasonal temperature extremes biasing of calculated mean temperatures toward seasons of maximum growth rate and dependence on the most extreme 18o values observed for estimating annual temperature range to better constrain paleoclimatic interpretations we describe several applications of a computational approach that address many of these uncertainties it is predicated on the presumption that annual variation in isotope composition across an accretionary skeleton represents sinusoidal variation in temperature and or the composition of ambient fluids the analysis resolves a best fit sinusoid for any portion of the data output consists of determinations of mean annual 18o seasonal range in 18o and sine period which reflects hardpart growth rate the procedure can be employed over some window of values within any data series and can be reiterated to arrive at solutions for all possible windows the technique allows for quantitative interpretation of mean values and annual amplitudes of 18o variation for every window regardless of whether or not that window actually spans a seasonal isotope extreme moreover it affords equal interpretational weight for every analysis in the data set in that mean annual and seasonal variation values estimated for each window are derived from every analysis in the data set it is therefore not necessary to estimate mean annual 18o as simply the arithmetic mean of all analyses and estimates of seasonality can be derived from data within any window rather than depending only on those several analyses that fall at compositional extremes in order to demonstrate the utility this methodology to the interpretation of paleoclimatological data we have applied it to published temperature data from several modern climatological data sets and to published 18o data from a paleogene gulf coast fish otolith a modern arabian sea coral a miocene texan equine tooth and an eocene bivalve from england each yields robust estimates of mean annual temperatures or isotopic compositions and of seasonal ranges in these values in addition unique features of data from each of these examples illustrate the power of this method to shed light on climatological and or biological phenomena that are also unique to each system

reconstructing enso the influence of method proxy data climate forcing and teleconnections in this study we compare three newly developed independent nino3 4 sea surface temperature sst reconstructions using data from 1 the central pacific corals 2 the texmex region of the usa tree rings and 3 other regions in the tropics corals and an ice core which are teleconnected with central pacific ssts in the 20th century although these three reconstructions are strongly calibrated and well verified inter proxy comparison shows a significant weakening in inter proxycoherenceinthe 19thcentury thisbreakdownin commonsignalcouldberelatedtoinsufficient data dating errors in some of the proxy records or a breakdown in el nino southern oscillation s enso s influence on other regions however spectral analysis indicates that each reconstruction portraysenso likespectralproperties superposedepochanalysisalsoshowsthateachreconstruction shows a generally consistent el nino like response to major volcanic events in the following year while duringyearst 4tot 7 la nina like conditions prevail theseresults suggest thateachofthe series expresses enso like behaviour but this behaviour does not appear to be spatially or temporally consistent this result may reflect published observations that there appear to be distinct types of enso variability depending on location within the tropical pacific future work must address potential dating issues within some proxies i e sampling of multiple coral heads for one location as well as assessing the time stability of local climate relationships with central pacific ssts more emphasis is needed on sampling new and extending old coral proxy records from the crucial central and eastern tropical pacific region copyright 2009 john wiley sons ltd and crown copyright 2009

an alkenone u 37 k quasi annual sea surface temperature record a d 1440 to 1940 using varved sediments from the santa barbara basin abstract analyses for c37 alkenones u37k and total organic carbon toc in a varved core from the depocenter of the santa barbara basin 34 13 5 n 120 01 w 590 m water depth have been made on an approximately 1 2 year basis from a d 1440 to 1940 the u37k based sea surface temperature sst record oscillates around 15 5 c with an amplitude of less than 3 c at approximately interannual decadal and centennial frequencies historical el nino southern oscillation enso events are matched only partially by warmer u37k ssts three records our sst a published pacific coral 18o and a published tree ring temperature anomaly from the california valleys show no evidence of colder temperatures during the little ice age ca 1500 to 1840 a d significantly there is a strong centennial scale cyclicity in the u37k sst record which approaches 1 c in amplitude toc burial and alkenone fluxes are largely controlled by sedimentation rate as expressed in varve thickness

a review of modern coral δ18o and δ14c proxy records abstract this paper is a review of published modern coral 18 o and 14 c isotopic records that are at least 30 and 20 years long respectively the data are presented to show basin scale trends in both of these proxy records on decadal to centennial timescales the goal was to qualitatively integrate the general inter annual to centennial timescale variability revealed in these data as well as the statistical and modeling output results that have been produced using these coral records while many review papers typically include a representative subset of the data available this review aims to include as much of the available data as possible in general coral 18 o records show a long term warming and or freshening throughout the tropical oceans and agree with the noaa extended reconstruction sea surface temperature 2 ersst on decadal timescales in the western pacific it is most likely a freshening of the seawater 18 o that dominates the signal el nino southern oscillation enso variability dominates most 18 o records either by varying local seawater temperature or salinity depending on the regional oceanography climatology outside of the pacific enso affects seawater temperature and salinity via atmospheric or oceanic teleconnections post bomb coral 14 c records collectively show that the uptake of 14 c has been greatest in gyre water fed sites followed in descending order by western boundary current areas equatorial upwelling regions and eastern tropical pacific upwelling sites these surface water 14 c values indicate the proportion of surface water and or the residence time of water at the surface at a given location and can be used to model water mass mixing rates such models have only begun to be run and show that the amount of eastern pacific water entering the central south pacific increases during el ninos and that the indonesian throughflow is supplied year round by the north pacific comparing ocean circulation models with coral 14 c modelled circulation enables researchers to explore the mechanisms that drive seawater 14 c variability and fine tune their models in addition our comparison between the rate of coral 14 c increase between 1960 and 1970 and total anthropogenic co 2 uptake rates show general agreement demonstrating the value of coral records in understanding past carbon fluxes overall coral 18 o and 14 c proxy records represent natural archives of seawater conditions and are critical for studying the natural variability in local and regional patterns within and teleconnection patterns between the tropics extra tropics temperate and polar regions on intra annual to centennial timescales

a mid twentieth century reduction in tropical upwelling inferred from coralline trace element proxies abstract the cariaco basin is an important archive of past climate variability given its response to inter and extratropical climate forcing and the accumulation of annually laminated sediments within an anoxic water column this study presents high resolution surface coral trace element records montastrea annularis and siderastrea siderea from isla tortuga venezuela located within the upwelling center of this region a two fold reduction in cd ca ratios 3 5 1 7 nmol mol is observed from 1946 to 1952 with no concurrent shift in ba ca ratios this reduction agrees with the hydrographic distribution of dissolved cadmium and barium and their expected response to upwelling significant anthropogenic variability is also observed from pb ca analysis observing three lead maxima since 1920 kinetic control of trace element ratios is inferred from an interspecies comparison of cd ca and ba ca ratios consistent with the sr ca kinetic artifact but these artifacts are smaller than the environmental signal and do not explain the cd ca transition the trace element records agree with historical climate data and differ from sedimentary faunal abundance records suggesting a linear response to north atlantic extratropical forcing cannot account for the observed historical variability in this region

diagnostic model of the three dimensional circulation in the upper equatorial pacific ocean abstract to investigate the processes that maintain the large scale annual average thermal structure of the equatorial pacific the three dimensional ocean circulation for a large area is determined from a diagnostic model applied to repeated meridional hydrographic sections along 150 w and 11o w from 5 n to 5 s geostrophic balances are used to determine velocity profiles from 0 to 500 db across the boundaries of the region zonal velocities across 150 w and 110 w at approximately 1 lattitude intervals from 5 n to 5 s and meridional velocities across 5 n and 5 s averaged over the zonal distance between 150 w and 110 w poleward wind driven flows across 5 n and 5 s based on climatological zonal wind stress are added to the geostrophic velocities in the mixed layers to achieve overall mass conservation the reference dynamic height field at 500 db is adjusted at four of the 21 stations by about 1 dyn cm horizontal nondivergence is used to determine meridional velocities between 0 75 and 5 latitudes

eastern pacific sea surface temperature since 1600 a d the δ18o record of climate variability in galapagos corals we measured stable oxygen isotope ratios and skeletal growth rates in the massive corals pavona clavus and p gigantea from the west coast of isabela island galapagos to assess interannual to decadal climate variability in the eastern pacific comparisons of instrumental data sets show that sea surface temperatures sst in the galapagos region are representative of a broad portion of the eastern equatorial pacific the site is especially well suited for long term studies of the el nino southern oscillation enso phenomenon as it lies within the eastern pacific center of action for thermal anomalies associated with enso the p gigantea isotope record is nearly monthly in resolution spans the period 1961 1982 and shows strong correlation with a galapagos instrumental sst record r 0 90 for annual averages cross spectral analysis shows that sst can explain greater than 80 of the variance in 18o at both the annual cycle and within the high frequency portion of the enso band 3 5 years the p clavus record is annual in resolution extends from 1587 to 1953 a d and was obtained from a 10 m diameter colony preserved within the urvina bay uplift because seawater 18o variations in the region are very small we interpret the urvina bay coral 18o record in terms of annual average sst the isotopic record appears to be a very good but not perfect indicator of enso events and shows good correspondence with the historical enso reconstruction of quinn et al 1987 a number of low 18o excursions that we observe during the 17th and 18th centuries very likely represent enso events that are missing from the historical tabulations most interannual 18o variations between 1607 and 1953 a d represent annual average temperature excursions of 1 to 2 5 c during the little ice age the annual 18o series correlates well with many north american tree ring records and shows low temperatures during the early 1600s and early 1800s and relatively warmer conditions during the 1700s unlike most northern hemisphere tree ring and instrumental records we see no evidence at this site for warming between 1880 and 1940 but rather observe a slight cooling 28 of the total variance the main enso mode is centered at 4 6 years and accounts for 12 of the total variance additional significant oscillations occur at periods of 3 3 6 8 11 17 22 and 34 years both annual growth rate and 18o show variance at periods equivalent to the solar and solar magnetic periods e g 11 and 22 years respectively in addition the amplitude of the 11 year 18o cycle generally varies with the amplitude of the solar cycle supporting previous suggestions that the solar cycle may modulate interannual to decadal climate variability in the tropics the dominant oscillatory modes both within the enso and interdecadal frequency bands shift to shorter periods from the early to middle 1700s and again from the middle to late 1800s this may reflect major reorganizations within the tropical ocean atmosphere system and suggests that tropical pacific climate variability is linked across timescales ranging from years to decades

trace metals in contemporary and seventeenth century galapagos coral records of seasonal and annual variations we report trace element calcium ratios for modern cuca mnca cdca and pbca and seventeenth century cuca mnca and pbca specimens of pavona clavus collected in the galapagos islands these data include the first reliable measurements of cuca ratios in coralline aragonite we estimate that the ratio of cuca in the lattice to that in seawater i e the effective distribution coefficient is 0 3 lower than the value of 1 observed for several other divalent elements we estimate the effective distribution coefficient for mn is 1 distribution coefficients in coral aragonite for 8 divalent metals are near unity despite different ionic radii and chemical speciation in seawater investigation of where these substituents are incorporated in the aragonite lattice is clearly warranted in a modern hood island coral quarter annually sampled from 1964 73 cuca ratios decrease twofold from the late 1960s to early 1970s mnca and cdca ratios vary seasonally with upwelling and the generic el nino the el nino southern oscillation enso events of 1965 1969 and 1972 are marked by suppression of cdca ratios by about 2 5 nmol mol while the mnca ratio is highest during the strong 1972 enso pbca ratios were relatively constant throughout this period from the cuca record of a seventeenth century urvina bay coral annually sampled from 1600 1725 and the estimated cu distribution coefficient surface seawater cu concentrations at galapagos during the seventeenth century were similar to present day at 0 7 1 4 nmol kg estimated pb concentrations were lower at 5 20 pmol kg and mn concentrations were slightly higher at 1 6 2 8 nmol kg

pleistocene sea levels from raised coral reefs of haiti the elevations and ages of a sequence of three uplifted pleistocene coral reefs on the northwest peninsula of haiti have been determined with the assignment of a sea level of 6 meters relative to the present day at 130 000 years before present and constant uplift of the reefs the data indicate that sea level stood 10 and 13 meters at 108 000 and 81 000 years before present respectively these results are in substantial agreement with those reported for barbados and new guinea and support the hypothesis of constant uplift for each area sea level data from raised reefs indicate that the interglacial marine oxygen isotope oscillations during oxygen isotope stage 5 are a result of 30 percent ice volume effects and 70 percent temperature effects

a 173 year stable isotope record from a tropical south pacific coral 0 we have generated a 173 year long time series a d 1806 to 1979 of changes in the 18 o and 13 c composition of a coral head platygyra lamellina to investigate environmental change in the climatologically sensitive region of the tropical south pacific little is known about decadal and centennial scale climate change at sea level in this region our coral is from near the south coast of espiritu santo island 15 s 167 e republic of vanuatu the stable isotope record from this coral is consistent with meteorological and oceanographic records during the period of overlap in the records 1964 1978 18 o values positively correlate with sst r 0 77 and 13 c values are highly coherent with rainfall r 0 82 at the annual cycle these relations suggest that the 18 o signal in this coral is a function of variations in sst and rainfall induced changes in sss whereas the 13 c signal may be related to rainfall and cloud cover modulation of photosynthesis in the coral 18 o and 13 c values are positively correlated over the entire length of the record r 0 65 a relation that is even stronger between 1806 and 1866 r 0 81 i e prior to the time of possible anthropogenic influence on the 13 c record because of the positive correlation between temperature and rainfall in this region we interpret the long term record of 18 o in terms of joint variations of these two variables the most significant cool dry excursion in the santo record occurs during the nineteenth century 1832 1866 and ends abruptly in 1866 with a change to modern values superimposed on this pattern is a slight 0 2 cooling drying toward the end of the twentieth century cross spectral analysis of the 18 o and 13 c records indicates a strong concentration of variance at the quasi biennial 2 years and el nino southern oscillation enso 4 5 years frequency bands in addition to a 15 year peak found also in global temperature records cross spectral analysis of coral isotope records from santo and the philippine sea indicate a concentration of variance at enso 4 5 years frequency bands however comparison of the santo coral isotope record with high latitude northern hemisphere temperature records indicates that the major cool dry excursion in the santo record 1832 1866 is not seen in the northern hemisphere record if verified in other tropical south pacific coral records the results have implications concerning the global scale of cooling for little ice age events

on the distribution of copper nickel and cadmium in the surface waters of the north atlantic and north pacific ocean concentrations of copper nickel and cadmium have been determined for about 250 surface water samples nonupwelling open ocean concentrations of these metals are cu 0 5 1 4 nmol kg ni 1 2 nmol kg and cd less than 10 pmol kg in the equatorial pacific upwelling zone concentrations of ni 3 nmol kg and cd 80 pmol kg are higher than in the open ocean but cu 0 9 nmol kg is not significantly enriched metal concentrations are higher in cool nutrient rich eastern boundary currents cu 1 5 nmol kg ni 3 5 nmol kg and cd 30 50 pmol kg copper is distinctly higher in the coastal waters of the gulf of panama 3 4 nmol kg and also higher in the shelf waters north of the gulf stream 2 5 nmol kg these copper enrichments may be caused by copper remobilized from mildly reducing shelf sediments and maintained by a coastal nutrient trap in the open ocean events of high cu water 1 5 3 5 nmol kg are seen on scales up to 60 km presumably these are due to the advection of coastal water into the oceanic interior the lowest copper concentrations in the north pacific central gyre 0 5 nmol kg bruland 1980 are lower than in the sargasso sea 1 3 nmol kg while for nickel the lowest concentrations are 2 nmol kg in both the north pacific and the north atlantic nickel and cadmium while generally correlated with the nutrients in surface waters show distinct regional changes in their element nutrient correlations the residual concentrations of trace metals in the surface waters of the ocean can be explained if biological discrimination against trace metals relative to phosphorus increases as productivity decreases

variations of upwelling intensity recorded in varved sediment from the gulf of california during the past 3 000 years circulation in the pacific ocean is periodically affected by el nino events which are a direct response to intensity changes in trade winds1 2 the appearance of anomalously warm surface water in the eastern equatorial pacific ocean is one of the most spectacular manifestations of this event warm surface water anomalies are also observed in the northern hemisphere along the californian coast and in the gulf of california in the gulf strengthened trade winds induce upwelling during the winter whereas in the summer prevailing southerly winds provoke an input of warm water from the south3 we have sampled laminated sediments from the slopes of guaymas basin to reconstruct with high resolution variations of the hydrology of surface waters in the central part of the gulf of california sedimentation rate is of the order of 4 mm yr 1 at the top and 1 2 mm yr 1 down core by analysing the oxygen isotope ratio of biogenic silica of diatoms4 we have recorded the surface water temperature variations in the guaymas basin the comparison of these fluctuations and variations of silicoflagellate abundance has allowed us to reconstruct changes in upwelling intensity during the past three thousand years the present conditions of low upwelling activity are seen to be abnormal in comparison with those prevailing in the past

non river flood barium signals in the skeletons of corals from coastal queensland australia abstract two corals from coastal queensland cow and calf islands and orpheus island have been analysed for a suite of trace elements by laser ablation icp ms la icp ms barium signals in these two corals are anomalous in comparison with ba behaviour seen in other near shore corals from this region the two corals display large sharp peaks in spring which do not correlate with markers of river discharge y ca and fluorescence this ba pattern contrasts with normal behaviour characterised here by the patterns previously published for two other coastal queensland corals king reef and pandora reef which display ba peaks in summer associated with flooding of nearby rivers 1 d j sinclair m t mcculloch corals record low mobile barium concentrations in the burdekin river during the 1974 flood evidence for limited ba supply to rivers palaeogeogr palaeoclimatol palaeoecol 214 1 2 2004 155 174 similarities are observed between the anomalous ba in the queensland corals and other published patterns of ba behaviour in corals from south africa and the arabian sea this non river flood ba behaviour is characterized by large sharp spikes of ba which are resistant to oxidative cleaning and form a continuous horizon within the coral curiously not all corals from a region display anomalous ba behaviour despite being in similar environments the timing of anomalous ba is consistent within a coral but may vary from one location to the next anomalous ba spikes are too large to be caused by ba rich upwelling and no single environmental forcing function seems to be able to account for their timing this combination of observations argues against an exogenous abiotic source for the anomalous ba signal instead it may result from a biological event triggered by a combination of environmental parameters three hypotheses are presented and critically tested against the observations barite inclusion following phytoplankton blooms decaying blooms of the blue green algae trichodesmium and physiological perturbations associated coral mass spawning none of the three hypotheses are fully consistent with all of the observations and it is concluded that no satisfactory explanation currently exists for the anomalous ba spikes

reconstructing el nino southern oscillation activity and ocean temperature seasonality from short lived marine mollusk shells from peru abstract a critical need exists for quantitative reconstructions of long term el nino southern oscillation enso variability in the eastern tropical pacific presented here is a method to quantitatively estimate past changes 1 in the seasonal amplitude of sea surface temperature sst in the peruvian coastal upwelling system and 2 in the amplitude of enso related interannual variability in the eastern tropical pacific the seasonal amplitude of sst t along the length of the peruvian coast is strongly correlated with the nino1 2 index we show that the frequency distribution of t values provided by a modern sample of 13 mesodesma donacium shells faithfully reflects modern enso variability at the regional scale including the range of anomalies from la nina to moderate el nino events but excludes extreme warm anomalies because of high shell mortality we propose to use the frequency distribution of enso anomalies in paleoclimate studies for comparisons between shell records coral records and gcm simulations reconstruction uncertainties can be quantified using monte carlo simulations the method presented here opens new perspectives for quantitative paleo enso reconstructions in the eastern pacific since it may be applied with any mollusk species from peru provided at least one annual cycle of sst is faithfully recorded by shell 18 o

vertical water mass mixing and plankton blooms recorded in skeletal stable carbon isotopes of a red sea coral the environmental interpretation of the 13c 12c variations in the skeletons of massive corals is still a matter of debate a 19 year seasonal skeletal 13c 12c record of a shallow water porites coral from the northern red sea gulf of aqaba documents interannual events of extraordinarily large plankton blooms indicated by anomalous 3c depletions in the coral skeleton these blooms are caused by deep vertical water mass mixing convectively driven in colder winters which results in increased supplies of nutrients to the surface waters the deep vertical mixings can sometimes be driven by the cooling occurring throughout the middle east after large tropical volcanic eruptions we therefore have evidence in our coral skeletal 13c 12c record for an indirect volcanic signal of the eruptions of e1 chich6n 1982 and mount pinatubo 1991 deep mixing induced 13c 12c variations of the dissolved inorganic carbon in the surface waters can be neglected at this location we therefore suggest that the 3c skeletal depletions can be best explained by changes in the coral s autotrophy heterotrophy diet through increased heterotrophic feeding on zooplankton during the blooms increased feeding on 3c depleted zooplankton or increased heterotrophy at the expense of autotrophy can both 3 result in a c depleted coral skeleton however this suggestion requires more testing if our conclusions are substantiated seasonal skeletal 3c r2c records of corals which change from autotrophy under normal conditions to increased heterotrophy during bloom events may be used as indicators of ocean paleoproductivity at interannual resolution available from no other source

carbon and oxygen isotopic composition of a guam coral and their relationships to environmental variables in the western pacific we examine the high resolution 32 samples year carbon and oxygen isotopic composition 13ccoral and 18ocoral in a coral core porites lobata from double reef guam over the years 1980 2000 the 13ccoral shows clear seasonal variations with mean seasonal amplitude of 1 89 which roughly corresponds with seasonal variations in solar radiation the seasonal amplitude of 18ocoral variations are small 0 23 0 57 but they are significantly correlated with sea surface temperature sst and salinity sss the 18ocoral and sst are more strongly correlated during el nino southern oscillation enso warm phases r 0 81 p 28 c and lower values of 18osw at guam these differences in oceanic parameters result from movements of the western pacific warm pool wpwp during the different phases of enso anomalies in 18osw inferred from the 18ocoral and instrumental sst are consistent with sss anomalies for the years 1980 2000 these 18osw anomalies may reflect changes in sss and evaporation precipitation due to movements of the wpwp this detailed analysis of a coral from guam suggests that it may contain an excellent archive of past enso events

porites corals as recorders of mining and environmental impacts misima island papua new guinea abstract in 1989 open cut gold mining commenced on misima island in papua new guinea png open cut mining by its nature causes a significant increase in sedimentation via the exposure of soils to the erosive forces of rain and runoff this increased sedimentation affected the nearby fringing coral reef to varying degrees ranging from coral mortality smothering to relatively minor short term impacts the sediment associated with the mining operation consists of weathered quartz feldspar greenstone and schist these rocks have distinct chemical characteristics rare earth element patterns and high abundances of manganese zinc and lead and are entering the near shore environment in considerably higher than normal concentrations using laser ablation inductively coupled plasma mass spectrometry la icp ms we analyzed eight colonies two from high sedimentation two transitional two minor and two unaffected control sites for y la ce mn zn and pb all sites show low steady background levels prior to the commencement of mining in 1988 subsequently all sites apart from the control show dramatic increases of y la and ce associated with the increased sedimentation as well as rapid decreases following the cessation of mining the elements zn and pb exhibit a different behavior increasing in concentration after 1989 when ore processing began and one year after initial mining operations elevated levels of zn and pb in corals has continued well after the cessation of mining indicating ongoing transport into the reef of these metals via sulfate rich waters rare earth element ree abundance patterns measured in two corals show significant differences compared to coral sea seawater the corals display enrichments in the light and middle rees while the heavy rees are depleted relative to the seawater pattern this suggests that the nearshore seawater ree pattern is dominated by island sedimentation trace element abundances of misima island corals clearly record the dramatic changes in the environmental conditions at this site and provide a basis for identifying anthropogenic influences on corals reefs

evaluation of sampling resolution in coral stable isotope records a case study using records from new caledonia and tarawa we have generated a 40 year long monthly stable isotope record from a porites lutea coral collected offshore of amedee new caledonia 22 s 167 e to investigate the relation between sampling resolution in coral isotope studies and retrieval of sea surface environmental information we interpret the high correlation between our oxygen isotope record and a twenty year long sea surface temperature record at the monthly timescale r 0 88 to indicate that our coral isotope record is an accurate monitor of environmental conditions offshore of amedee the character of the signal and the percent variance explained in the record at the annual band at the quasi biennial oscillation band qbo 2 0 2 4 years and at the el nino southern oscillation band enso 3 8 years changes little in response to a reduction in sampling density from monthly to bimonthly to quarterly similar results have been obtained in a reanalysis of a coral isotope record from tarawa kiribati our results indicate that a significant amount of the information obtained from high density sampling can also be retrieved from lower density sampling in particular bimonthly sampling yields virtually no drop off in variance explained and quarterly sampling is satisfactory for resolving interannual and decadal scale trends in time series the proposed sampling approach may enable a more rapid filling in of numerous spatial holes in coral sampling sites needed for reconstruction of long term decadal scale variations in climate

high resolution coral cd measurements using la icp ms and id icp ms calibration and interpretation abstract cadmium cd concentrations in coral skeleton track oceanic upwelling which brings cd rich deep water to the surface in this study we report sub monthly measurements of cd coral measured via laser ablation inductively coupled plasma mass spectrometry la icp ms in three species of coral porites lobata pavona gigantea and pavona clavus from an upwelling site in the gulf of panama although single la tracks in all species yielded variable results the average of multiple tracks mirrored changes in in situ seawater cd cd sw with an offset between peaks in addition cd coral determined by la icp ms and isotope dilution id icp ms was compared in p clavus and found to be highly correlated despite consistently lower concentrations measured using the id method two 5 5 month long high resolution p clavus cd coral records revealed that the maximum cd coral values occurred after the sea surface temperature minimum at the same time as the seawater phosphate concentration and coral p ca maximum and approximately one month before peak cd sw based on these findings we hypothesize that corals are actively taking up cd and incorporating it into their skeleton and that cd sw only increases once cd is no longer being rapidly removed from the water column via biological processes after accounting for a 1 month offset between the coral and seawater cd maxima both la and id derived cd coral values were significantly correlated to cd sw providing a calibration for this cd sw proxy in p clavus a three year high resolution p clavus la cd coral record demonstrated the potential of cd coral to generate a high resolution cd sw record however due to the natural variability in high resolution la icpms cd coral values within and among coral colonies three laser tracks per colony and at least three colonies of p clavus need to be analyzed to produce a reliable coral cd coral record

precise timing of the last interglacial period from mass spectrometric determination of thorium 230 in corals the development of mass spectrometric techniques for determination of 230 th abundance has made it possible to reduce analytical errors in 238 u 234 u 230 th dating of corals even with very small samples samples of 6 x 10 8 atoms of 230 th can be measured to an accuracy of 3 percent 2 and 3 x 10 10 atoms of 230 th can be measured to an accuracy of 0 2 percent the time range over which useful age data on corals can be obtained now ranges from about 50 to about 500 000 years for young corals this approach may be preferable to 14 c dating the precision with which the age of a coral can now be determined should make it possible to critically test the milankovitch hypothesis concerning pleistocene climate fluctuations analyses of a number of corals that grew during the last interglacial period yield ages of 122 000 to 130 000 years the ages coincide with or slightly postdate the summer solar insolation high at 65 n latitude which occurred 128 000 years ago this supports the idea that changes in pleistocene climate can be the result of variations in the distribution of solar insolation caused by changes in the geometry of the earth s orbit and rotation axis

two hundred fifty years of reconstructed and modeled tropical temperatures 1 recent large scale palaeoclimate reconstructions of past temperature have been essentially biased to the extratropics owing to a paucity of proxy data in tropical regions herein we describe the first coral based reconstruction of sea surface temperatures ssts for the whole of the tropics 30 n 30 s it was developed from 14 disparate coral records located in the indian and pacific oceans over the most replicated period the reconstruction explains 57 of the tropical sst variance however the strength of this signal weakens markedly as the number of coral records decreases the reconstruction is robust between 1850 and 1993 but some fidelity is indicated back as far as the mid 18th century these results suggest that ambiguities in the low frequency domain of 18o measurements can be partially overcome by pooling together multiple time series from different locations around the tropics agreement with simulations from two general circulation models indicates that the late 20th century is likely the warmest period in the tropics for the last 250 years and that this recent warming can only be explained by anthropogenic forcing the high frequency variability is dominated by the el nino southern oscillation the reconstruction owing to the small number of coral records is unfortunately restricted both in time and space therefore we hope that this study will spur the palaeoclimate community to develop new and longer proxy series to improve the current meager data base of temperature sensitive series in the tropics

the temperature relationship in coralline aragonite influence of variability in and skeletal growth parameters this paper provides an evaluation of two of the most likely pitfalls of sr ca thermometry i e the effect of biogenic cycling of sr vs ca in the surface ocean and the effect of variable extension rate on sr incorporation in coralline aragonite the authors also report calibration of the sr ca temperature relationship for three coral species porites lobata pocillopora eydouxi and pavona clavus collected for the hawaiian and galapagos islands analyses of seawater samples show significant spatial and depth variability in the sr ca ratio the uncertainty introduced by this effect is estimated to be 0 2 degrees c for corals located in tropical oligotrophic waters and potentially larger for corals located in upwelling areas sr ca along two different growth axes of a galapagos pavona clavus with annual extension rates of approximately 6 and 12 mm y respectively indicate an offset of 1 2 degrees c with higher sr ca values associated with slower extension rates the offset observed between the two growth axes may be the result of variations in extension and or calcification rate these results are important in determining past sea surface temperatures for reconstruction of paleoclimates

lithium in the aragonite skeletons of massive porites corals a new tool to reconstruct tropical sea surface temperatures previous studies have demonstrated the potential for the li content of coral aragonite to record information about environmental conditions but no detailed study of tropical corals exists here we present the li and mg to ca ratios at a bimonthly to monthly resolution over 25 years in two modern porites corals the genus most often used for paleoclimate reconstructions in the tropical indo pacific a strong relationship exists between coral li ca and locally measured sst indicating that coral li ca can be used to reconstruct tropical sst variations however li ca ratios of the skeleton deposited during 1979 1980 do not track local sst well and are anomalously high in places the mg ca ratios of this interval are also anomalously high and we suggest li ca can be used to reconstruct tropical sst only when mg ca data are used to carefully screen for relatively rare biological effects mg li or li mg ratios provide little advantage over li ca ratios except that the slope of the li mg temperature relationship is more similar between the two corals the mg li temperature relationship for the coral that experienced a large temperature range is similar to that found for cold water corals and aragonitic benthic foraminifera in previous studies the comparison with data from other biogenic aragonites suggests the relationship between li mg and water temperature can be described by a single exponential relationship despite this hint at an overarching control it is clear that biological processes strongly influence coral li ca and more calibration work is required before widely applying the proxy

lead in corals reconstruction of historical industrial fluxes to the surface ocean twentieth century environmental lead chronologies for the western north atlantic pacific and indian oceans have been reconstructed from annually banded scleractinian corals measurements of lattice bound pb in sequential coral bands reveal temporal changes in surface water pb concentrations and pb isotopic distributions perturbations are observable in all specimens studied attesting to global augmentation of environmental pb by industrialization in the western north atlantic pb perturbations have occurred in direct response to the american industrial revolution and the subsequent introduction and phasing out of alkyl pb additives in gasoline surface ocean conditions near bermuda may be reliably reconstructed from the coral data via a lead distribution coefficient of 2 3 for the species diploria strigosa based on210pb measurements a similar distribution coefficient may be characteristic of corals in general surface pb concentrations in the pre industrial sargasso sea were about 15 20 pm concentrations rose to near 90 pm by 1923 as a result of metals manufacture and fossil fuel combustion beginning in the late 1940 s increased utilization of leaded gasoline eventually led to a peak concentration of 240 pm in 1971 representing an approximate 15 fold increase over background surface ocean concentrations are presently declining rapidly 128 pm in 1984 as a result of curtailed alkyl pb usage lead isotopic shifts parallel the concentration record indicating that characteristic industrial and alkyl pb source signatures have not changed appreciably in time industrial releases recorded in the florida keys reflect a weaker source and evidence of recirculated pb 5 6 years old from the north atlantic subtropical gyre an inferred background concentration of 38 pm suggests influence of shelf and or resuspended inputs of pb to these coastal waters in remote areas of the south pacific and indian oceans industrial signals are fainter and the corals studied much younger than their atlantic counterparts contemporary pb concentrations implied by coral measurements assumingkd 2 3 are 40 50 pm for surface waters near tutuila and galapagos in the south pacific and 25 29 pm near mauritius in the indian ocean a single coral band from fiji 1920 5yr implies a pre industrial surface water concentration of 16 19 pm pb for the south pacific in view of reported surface water measurements and the north atlantic coral data the pacific coral extrapolations may be slightly high this could be a result of small variations inkd among different coral genera or incorporation of diagenetic pb by corals sampled in coastal environments

barium in planktonic foraminifera abstract reconstructions of ba distributions in ancient oceanic surface waters could provide new insight into paleoceanographic change calcite shells of planktonic foraminifera potentially provide a means of reconstructing such paleo ba distributions if lattice bound ba can be determined on shells recovered from deep sea cores planktonic foraminifera shells from a series of cores were purified of non lattice bound ba associated with organic or sedimentary phases by a combination of physical agitation oxidative reductive steps acid leaches and a novel alkaline dtpa step to dissolve barite a sequential dissolution of a large sample of cleaned shells of the planktonic foraminifer globigerinoides conglobatus indicates homogeneous distribution of ba in the shell material comparison of shells from sediments sediment traps and plankton tows indicates no significant differences in the ba content of the purified shells cleaned samples of the planktonic foraminifera globigerinoides sacculifera g ruber g conglobatus orbulina spp and globoquadrina dutertrei from the equatorial pacific north atlantic and mediterranean sea have ba ca ratios between 0 6 and 1 0 mol mol 0 8 to 1 4 ppm variation in foraminiferal ba contents between the three basins is consistent with the trend in surface seawater ba the calculated distribution coefficient for ba incorporation in these five species based on these data is 0 19 0 05 several species of the non spinose planktonic foraminifera globorotalia have ba ca ratios ranging from 2 to 13 mol mol these high ba contents might be explained by differences in the way these foraminifera precipitate their shells a temporal record of ba ca in samples of globigerinoides and orbulina from a core in the northwest atlantic suggests that the ba concentration of surface waters at this site has not changed by more than 20 over the last 14 kyr

a high resolution sr ca and δ18o coral record from the great barrier reef australia and the 1982 1983 el nino abstract a high resolution near weekly sr ca and oxygen isotopic record is presented for a coral from the pandora reef in the great barrier reef gbr of australia during the period 1978 to 1984 the records are well correlated except for periods of high rainfall when river runoff has significantly modified the 18o value of seawater using the sr ca temperature calibration of de villiers et al 1994 the sr ca records exhibit seasonally controlled cyclical sst sea surface temperature variations of from 21 to 28 c during the very strong el nino of 1982 1983 the sr ca systematics indicate a sharp drop in the winter sst to 18 5 c this represents a temperature anomaly of 3 c which is approximately twice that given by the 18o variations suggesting an 2 amplification of the anomaly by the sr ca system possibly due to the increasing dominance of inorganically controlled aragoniteseawater fractionation the oxygen isotopic systematics show the combined effects of both temperature and changing seawater 18o values the latter reflecting the influx of 18o depleted runoff during periods of high rainfall due to the extremely low 10 3 sr and ca contents of river run off relative to seawater it is possible to use the sr ca thermometer to calculate temperatures independent of major floods and hence deconvolve the combined effects in the oxygen isotopic record of variable temperature and the 18o value of seawater using this approach it is possible to quantitatively reproduce the volume of runoff from the burdekin river during the periods of major flooding that occurred in early 1979 and 1981 the results of this study demonstrate that the combined use of high resolution sr ca and 18o systematics in scleractinian corals is a powerful tool for providing quantitative constraints on past climate

foraminiferal reconstruction of barium distributions in water masses of the glacial oceans foraminiferal ba can be used to reconstruct the distribution of deeply regenerated chemical components in past oceans the ba contents of benthic foraminifera recovered from cores in the atlantic ocean indicate that waters deeper than 2900 m had 30 60 higher ba during the last glacial maximum lgm these changes are consistent with previously observed glacial nutrient enrichments based on foraminiferal cd and 13c increases in deepwater nutrient contents in the atlantic can be explained by reductions in north atlantic deep water formation during the lgm ba ca of benthic foraminifera from the glacial sections of intermediate depth atlantic cores are equal to or lower than holocene values this ba evidence argues against the mediterranean as a greatly increased source to atlantic intermediate waters during the lgm since the mediterranean is enriched in ba today and apparently remained enriched during the lgm benthic foraminiferal ba from the glacial sections of cores from the eastern equatorial pacific suggest that deep waters of the glacial pacific were about 25 lower in ba at 3000 m taken together the foraminiferal evidence indicates that the ba content of deep waters of the atlantic antarctic and pacific were similar at the lgm since foraminiferal cd distributions indicate that cd remained significantly lower in the deep atlantic relative to the pacific at the last glacial maximum a seven box ocean model is used to explore several scenarios for reconciling lgm ba and cd distributions while the changed distribution of both tracers suggests diminishment in the flux of nutrient depleted waters to the deep atlantic during the lgm increased atlantic upwelling rates and consequently enhanced ba particle fluxes can account for the the lack of ba fractionation between the deep atlantic and pacific the model suggests that ba can be transferred efficiently to the deep atlantic by enhanced upwelling because the vast majority of the ba is regenerated in the deep atlantic box

changes in the distribution of δ13c of deep water σco2 between the last glaciation and the holocene carbon isotopic measurements on the benthic foraminiferal genus cibicidoides document that mean deep ocean 13c values were 0 46 lower during the last glacial maximum than during the late holocene the geographic distribution of 13c was altered by changes in the production rate of nutrient depleted deep water in the north atlantic during the late holocene north atlantic deep water with high 13c values and low nutrient values can be found throughout the atlantic ocean and its effects can be traced into the southern ocean where it mixes with recirculated pacific deep water during the glaciation decreased production of north atlantic deep water allowed southern ocean deep water to penetrate farther into the north atlantic and across low latitude fracture zones into the eastern atlantic mean southern ocean 13c values during the glaciation are lower than both north atlantic and pacific 13c values suggesting that production of nutrient depleted water occurred in both oceans during the glaciation enriched 13c values in shallow cores within the atlantic ocean indicate the existence of a nutrient depleted water mass above 2000 m in this ocean

the radiocarbon record in varved sediments of carmen basin gulf of california a measure of upwelling intensity variation during the past several hundred years the decrease in 14c 12c with depth in a varved sediment core raised from the eastern flank of carmen basin gulf of california is greater than expected from varve and 210pb chronology the discrepancy is ascribed to a virtually monotonic decrease in upwelling intensity from several hundred years ago to the present this radiochemical study presents an approach independent of previously used biostratigraphic techniques for evaluating temporal variations in upwelling intensity in the gulf of california

coral barium calcium record of mid holocene upwelling activity in new caledonia south west pacific abstract a variety of inimical factors i e sea surface temperature nutrient input nature of substrates were invoked previously to explain the retardation in reef settlement in new caledonia during the holocene in order to clarify the respective role played by temperature and nutrient level in the growth of fringing reefs along the southwest coast of the island trace element ratios i e sr ca and ba ca were used respectively as a paleothermometer and as a tracer of nutrient load from modern and mid holocene about 6000 calendar years old massive porites coral colonies the results obtained from the modern coral record indicate that near the outer barrier reef upwelling activity is controlled by southeast winds blowing in summer by contrast along the southwest coastline the fringing reefs are subjected to barium input mainly derived from weathering of barite rich rocks cropping out in the adjacent mainland comparison between the fossil and modern coral sr ca and ba ca records shed light on three different aspects of the mid holocene climate and coral reef evolution in new caledonia 1 the variability of paleo sea surface temperature sst seems to have been similar to the modern one although the island probably experienced sst about 1 c higher than at present 2 upwelling activity appears to have been greater than at present barium being supplied from the open sea to coastal zones by strong wind generated upwelling currents in relation to cooling events 3 the onset of reef development in the southwest areas of new caledonia was delayed due to the stronger upwelling of nutrient enriched waters during the early middle holocene the flowing of upwelled waters over the southwest coastal areas began at 8200 calendar years bp and ceased at the time when the outer barrier reef crest reached present day sea level about 5500 to 5000 calendar years ago