the evolution of oceanic and atmospheric anomalies in the northeast pacific during the el nino and la nina events of 1995 2001 abstract from late 1995 through early 2001 three major interannual climate events occurred in the tropical pacific the 1995 97 la nina ln 1997 98 el nino en and 1998 2001 ln we analyze atmospheric and upper oceanic anomalies in the northeast pacific nep during these events and compare them to anomalies both elsewhere in the north and tropical pacific and to typical en and ln anomaly patterns the atmospheric and oceanic anomalies varied strongly on intraseasonal and interannual scales during the 1995 97 ln and 1997 98 en the northeast pacific was dominated by negative slp and cyclonic wind anomalies and by upper ocean temperature and sea surface height ssh anomalies the latter were positive along the north american west coast and in the nep thermal anomaly pool between hawaii vancouver island and baja california and negative in the central north pacific this atmospheric oceanic anomaly pattern is typical of en an eastward shift in the atmospheric teleconnection from east asia created en like anomalies in the nep during the 1995 97 ln well before the 1997 98 en had begun the persistence of negative sea level pressure slp and cyclonic wind anomalies in the nep during the 1997 98 en intensified pre existing upper oceanic anomalies atmospheric anomalies were shifted eastward during late 1996 early 1998 leading to a similar onshore shift of oceanic anomalies this produced exceptionally strong positive upper ocean temperature and ssh anomalies along the west coast during the 1997 98 en and explains the unusual coastal occurrences of several species of large pelagic warm water fishes the growth and eastward shift of these pre existing anomalies does not appear to have been linked to tropical pacific en anomalies until late 1997 when a clear atmospheric teleconnection between the two regions developed prior to this remote atmospheric impacts on the nep were primarily from east asia as the 1998 2001 ln developed nep anomalies began reversing toward the typical ln pattern this led to predominantly negative slp and cyclonic wind anomalies in the nep and upper ocean temperature and ssh anomalies that were mainly negative along the west coast and positive in the central north pacific the persistence of these anomalies into mid 2001 and a number of concurrent biological changes in the nep suggest that a decadal climate shift may have occurred in late 1998 during 1995 2001 nep oceanic anomalies tracked the overlying atmospheric anomalies as indicated by the maintenance of a characteristic spatial relationship between these anomalies in particular wind stress curl and ssh anomalies in the nep maintained an inverse relationship that strengthened and shifted eastward toward the west coast during late 1996 early 1998 this consistent relationship indicates that anomalous ekman transport driven by regional atmospheric forcing was an important contributor to temperature and ssh anomalies in the nep and ccs during the 1997 98 en other studies have shown that coastal propagations originating from the tropical pacific also may have contributed to coastal nep anomalies during this en our results indicate that at least some of this coastal anomaly signal may have been generated by regional atmospheric forcing within the nep

origin and evolution of cycladophora davisiana ehrenberg radiolaria in dsdp site 192 northwest pacific this paper documents the evolutionary history of cycladophora davisiana ehrenberg from an uppermost miocene to pleistocene sedimentary record in the high latitude northwest pacific it apparently evolved from c sakaii motoyama through a series of intermediates c sakaii has a relatively large shell with an external spongy layer the evolutionary transition is characterized by a relatively rapid decrease in thorax size with a reduction of the spongy appendage this change occurred during about 0 4 m y from 2 8 to 2 4 ma without cladogenesis following this interval a decrease in thorax size continued gradually up to the recent resulting in a very small morphology although the population of c davisiana first appeared at about 2 5 ma some morphotypic specimens may occur in earlier periods as indistinguishable very small endmembers in the c sakaii populations timing of the first appearance events both of morphotypic specimens and of a population of c davisiana in site 192 and previously reported cores does not disprove the idea that c davisiana evolved first in the northwest pacific region and later migrated into other regions of the world ocean biometrics clearly indicate no direct phylogenetic relationships between c davisiana and c cornutoides kling in the studied core thus the latter species which was originally described as a variation and later elevated to a subspecies of the former species is separated from the former species and raised to the species rank

the production scheme of cycladophora davisiana radiolaria in the okhotsk sea and the northwestern north pacific implication for the paleoceanographic conditions during the glacials in the high latitude oceans 1 the sediment trap study clearly unraveled that the distinct peaks of c davisiana fluxes occurred during summer to autumn in both the okhotsk sea and the northwestern north pacific the production of c davisiana is closely related to the microbial production in the intermediate water in the okhotsk sea the distinct microbial biomass in the intermediate water which is associated with the seasonal sea ice rejected brine water during winter may support the high c davisiana abundance therefore the significantly high c davisiana abundance during the last glacial maximum lgm in the high latitude open oceans implies the distinct microbial biomass in the intermediate water caused by the seasonal sea ice coverage analogous to the present okhotsk sea

extraterrestrial iridium sediment accumulation and the habitability of the early earth s surface we have measured the concentrations of iridium and platinum in ancient metasediments from akilia island southern west greenland to obtain the first direct constraints on the extraterrestrial mass flux at the earth s surface before 3 8 gyr the lunar impact record indicates this was a time of heavy bombardment the average lunar cratering rate between 4 15 and 3 8 gyr was elevated 150 times the modern value hence heightened ir and pt abundances are possible in sediments from this time however the observed concentrations of ir and pt in the akilia metasediments are extremely low in most samples ir 3 ppt and pt 20 ppt in contrast the average modern crustal abundances of ir and pt are 50 ppt and 2 ppb respectively the very low concentrations observed in the akilia metasediments cherts and banded iron formations can be reconciled with the lunar record by quantifying the effects of sedimentation rate on the efficiency with which the extraterrestrial mass flux is sampled the observations are explained if rapidly accumulating sediments sampled stochastic bombardment by an impactor population governed by a power law mass distribution such that exogenous ir and pt are concentrated in rare horizons the required sedimentation rates are geologically plausible this explanation has two consequences first evidence of massive impact events may be rare in sediments older than 3 8 gyr despite heavy bombardment second conditions at the earth s surface may have been conducive for extensive accumulation of sedimentary sequences and for microbial life during most of the period 4 15 3 8 gyr it is possible that the earth s surface hosted microbial habitats during most of this time if microbes living in deep sea or deep crustal environments survived photic zone vaporizing impacts that would have occurred every 30 myr hence evidence of life is expected even in the earliest sedimentary sequences

the bering sea and paleoceanography abstract this paper serves as an introduction to the bering sea preceding the 14 contributed papers contained in this volume several parts of the paper are allocated for current reviews of the bering sea included in the review topics are geomorphology surface water circulation and the importance of the formation of intermediate waters representative results of previous paleoceanographic studies are also presented in particular focusing on spatial and temporal distributions of biosiliceous microfossils as well as isotopic analyses of carbon and nitrogen concerning changes in productivity and nutrients motivations behind the scientific expeditions conducted which resulted in the many papers included here are briefly discussed in order to illustrate the recent trend in paleoceanography in the bering sea and the adjacent regions brief summaries or highlights of each of the contributed papers are given in order to provide an overview of the volume

radiolarian faunal provinces in surface sediments of the greenland iceland and norwegian gin seas the overall abundance and species composition of the polycystine and phaeodarian radiolaria have been determined in 63 surface sediment samples from the gin seas these results are compared to chemical and physical properties of the overlying water masses there are three abundance maxima in the distribution of radiolarian skeletal debris preserved in these surface sediments centered on the iceland plateau southern norwegian basin and northern norwegian basin the most commonly encountered species were a spumellarida actinomma boreale a leptoderma larcospira minor and phorticium clevei b nassellarida amphimelissa setosa artobotrys boreale lithomelissa setosa lithocampe platycephala pseudodictyophimus gracilipes cycladophora davisiana a ndlithomitra lineata based on factor analysis of the core top assemblages the radiolarian species were grouped into three associations factor 1 a polar and arctic water association dominated by amphimelissa setosa varimax factor score 5 269 high factor component values are found in the iceland plateau area and in a wedge just north of the iceland faeroe ridge factor 2 an atlantic water association dominated by pseudodictyophimus gracilipes 3 247 lithomelissa setosa 2 731 and actinomma boreale 1 851 high factor component values are found in the eastern part of the norwegian sea particularly in the area under the influence of the norwegian current and factor 3 an atlantic and arctic water mixed association dominated by lithocampe platycephala 3 251 lithomelissa setosa 2 176 actinomma leptoderma 1 994 and artobotrys boreale 1 504 high factor component values are found immediately to the east of the iceland plateau in correspondence to the deepest part of the norwegian basin the correlation coefficients obtained between seasonal sea surface temperature and factors 1 r 2 d 0 835 a nd 2 r 2 d 0 891 show a good fit whilst for factor 3 there was a less marked r 2 d 0 497 but still significant at the 5 confidence level correlation for fifth degree polynomial regression functions the factors correlated better with the summer than the winter sea surface temperatures however at 20 50 100 and 200 m depth the correlation became increasingly better particularly so for the winter situation the highest species richness for polycystine radiolarians 28 species was found in the warm atlantic domain the lowest 24 species was found in the colder arctic and polar domains whilst an area approximating the position of the arctic front had between 24 and 28 species 1998 elsevier science b v all rights reserved

woce section p1w in the sea of okhotsk 1 oceanographic data description we describe the results of a world ocean circulation experiment woce survey line p1w from the open pacific ocean through the bussol strait and across the sea of okhotsk observations are presented of distributions of temperature and salinity dissolved oxygen and nutrients and some derived quantities discussion centers on the distribution of the sea of okhotsk component of the north pacific intermediate water mass and its properties the sea of okhotsk has been suggested as the only location where deep convection may occur within the north pacific or its marginal seas our analysis suggests that the surface 26 85 has recently been ventilated and arguments might be made to suggest that ventilation has occurred to 27 05 this is discussed here but detailed evidence is covered in a companion paper analyzing cfc observations the okhotsk component of the north pacific intermediate water extends to substantially greater depths and densities and so some other process is needed to create the denser water mass

woce line p1w in the sea of okhotsk 2 cfcs and the formation rate of intermediate water from august 30 to september 21 1993 temperature salinity nutrient and cfc data were collected along a section starting in the pacific ocean near bussol strait in the kuril islands crossing the basin and shelf region of the sea of okhotsk and ending near the coastal town of okhotsk at the northwest corner of the sea of okhotsk world ocean circulation experiment woce line p1w water on the continental shelf had potential density as great as 27 0 with high cfc concentrations and low temperature and salinity the sea of okhotsk intermediate water soiw ranging from 26 8 to 27 4 had uniform water properties along isopycnal surfaces that were distinctly different from either the north pacific intermediate water npiw or the shelf water found at the same density since the soiw was colder and fresher than the npiw we postulate that soiw is formed by sinking plumes and diapycnal mixing shelf derived water sdw as dense as 27 0 is formed on the shelf during the winter by cooling and brine rejection during ice formation prevailing winds move the sdw off the shelf where it sinks to an equilibrium depth and subsequently mixes isopycnally with north pacific water npw flowing into the sea of okhotsk through the kuril islands the observations on the shelf suggest that sdw directly modifies soiw to 27 0 using potential temperature salinity s and cfc data we calibrated a simple box model to determine the input of sdw into the soiw model results required a minimum of 0 9 sv 1 sv 10 6 m 3 s 1 of sdw in the formation of soiw and produced a minimum export of 2 7 sv of soiw from the sea of okhotsk our minimum calculated export of soiw into the north pacific ocean makes the sea of okhotsk a significant source of the salinity minimum present in the npiw below 27 2 the box model failed because the cfc concentrations of the sdw were too high this suggests that sdw directly ventilates the soiw to a maximum of 27 2 the unique properties of the soiw below 27 2 must be the result of diapycnal mixing in the sea of okhotsk and isopycnal mixing with inflowing npw

spatial distribution pattern of living polycystine radiolarian taxa baseline study for paleoenvironmental reconstructions in the southern ocean atlantic sector the horizontal and vertical distribution of living polycystine radiolarian taxa was investigated at seven locations on a n s transect between the antarctic zone 54 s in the southern ocean and the subtropical zone 30 s in the southeastern south atlantic during austral autumn four to five depth intervals from 0 to 1000 m depth were sampled with 55 m mesh opening closing nets in combination with a hydrographic ctd survey a factor analysis for the delineation of specific assemblages and the relation between different taxa and taxa groups resulted in eight factors of which five represent surface and subsurface factors and three deep water factors the spatial distribution pattern of the factors shows that distinct radiolarian assemblages are closely related to water depth distribution of water masses hydrographic boundaries such as frontal systems and nutrients this documents that the distribution of individual radiolarian assemblages is controlled by specific hydrographic conditions and water depth and allows the definition and consolidation of the autecological demands these data are crucial for the paleoenvironmental interpretation of fossil polycystine radiolarian assemblages the comparison of living polycystine radiolarian taxa with those preserved in surface sediments shows general similarities this study includes the first documentation on the distribution of living cycladophora davisiana in circumpolar deep water and supports previous studies stating that c davisiana also lives in deep water masses

comparison of radiolarian vertical distributions in the okhotsk sea near the kuril islands and in the northwestern north pacific off hokkaido island abstract the vertical distribution of radiolarians was investigated by using a closing type net with 63 m mesh in the okhotsk sea station nu 2 near bussol strait down to 1000 m depth and in the northwestern north pacific oyashio region station x down to 500 m depth both stations were sampled in september 1995 radiolarian standing stocks were high between 50 and 200 m at both stations and generally decreased with depth the depth integrated living total radiolarian standing stock from 0 to 500 m at station nu 2 was more than three times higher than that at station x the maximum standing stocks of polycystine radiolarians occurred in the 50 100 m depth interval but there were also significant abundance peaks of phaeodarian radiolarians in the 100 200 m interval at both stations the radiolarian production is likely to be associated with not only phytoplankton production in upper waters but also with microbial production in intermediate waters a total of 79 taxa were encountered 25 spumellaria 41 nassellaria and 13 phaeodaria five radiolarian groups were obtained based on r mode cluster analysis group a lower intermediate water dwellers 300 1000 m group b taxa with different distributions in the okhotsk sea 300 1000 m and in the oyashio region 0 100 m group c upper intermediate water dwellers 200 500 m group d surface subsurface water dwellers 0 200 m and group e taxa with pronounced 200 m

sm nd systematics of a tonalitic augen gneiss and its constituent minerals from northern michigan abstract the sm nd isotopic system of a tonalitic augen gneiss and its constituent minerals from northern michigan was disturbed during metamorphism sm nd zircon ages are lower than the wholerock sm nd model age however closely associated pairs of minerals for example sphene and biotite or apatite and plagioclase retain their apparent metamorphic ages the sm nd model age for the tonalitic augen gneiss of 3919 30 myr appears to reflect open system behavior during metamorphism a mineralogically different gneiss from the same location has a sm nd model age of 3520 70 myr the two whole rocks differ in their sm nd and rb sr systematics and in their chondrite normalized rare earth element ree patterns the whole rock normalized mineral ree patterns show the contribution of the major and trace minerals to the ree content of the whole rock the trace minerals contain a significant amount of the total ree

temporal and spatial flux changes of radiolarians in the northwestern pacific ocean during 1997 2000 abstract in order to examine the radiolarian fluxes and evaluate their relationship to the physical and biological environments time series sediment traps were deployed at three stations stations 50n knot and 40n in the northwestern north pacific from 1997 to 2000 station 50n 50 n 165 e 3260 m is located in the center of western subarctic gyre wsag station knot 44 n 155 e 2957 m is located toward the margin of wsag and station 40n 40 n 165 e 2986 m is located in the subarctic boundary total radiolaria fluxes at station 40n showed higher values than those at the other two stations and were mainly attributed to the influence of relatively high temperature and high salinity subtropical gyre waters correlation coefficients between total mass fluxes mainly composed of diatoms and radiolarian fluxes at three stations were relatively low this is primarily because of the wide vertical distribution of radiolarians and various trophic patterns corresponding to their niche radiolarian species were classified according to their geographic water mass and vertical distributions based on previous studies using sediment samples as a result seasonal changes of radiolarian fluxes in each water mass showed patterns corresponding to particular controlling factors such as physical hydrography and food conditions among these patterns temporal changes in radiolarian taxonomic composition in the upper layer 0 100 m seemed to reflect well the sea surface temperature anomaly ssta changes affected by el nino and la nina events at station 40n therefore radiolarian assemblages can be used to reconstruct past ssta changes and to understand the past el nino and la nina teleconnection in the kuroshio oyashio extension region

phaeodarian skeletons their role in silica transport to the deep sea the skeletons of phaeodarian radiolaria transport and redistribute silica to the tropical deep oceans by dissolving in the water column and on the sea floor the skeletons are initially solid but within a few days to months become progressively more porous while settling through the water column phaeodarian radiolaria are rarely preserved in the bottom sediments in contrast polycystine radiolaria are the dominant radiolaria preserved in the fossil record this preservational difference may be due to differences in skeletal constituents

distribution of polycystine radiolarians in the northern south china sea in september 2005 we studied the distribution of polycystine radiolarians in the northern south china sea scs in september 2005 in order to document the relation between radiolarian assemblages and environmental parameters vertical plankton tows were collected at depth intervals from 0 to 250 m at thirteen stations using a closing net 62 pm mesh the highest abundance of polycystine radiolarians generally occurred at depths of 0 75 m i e above the chlorophyll a maximum and thermocline in contrast the maximum polycystine abundance occurred below the chlorophyll a maximum at station e105 75 150 m possibly as a result of down welling of warm waters and the maximum fell within the chlorophyll a maximum at station e702 as a result of upwelling of intermediate cold waters during our sampling period the southwestern monsoon caused upwelling in the northern scs the taiwan bank region as shown by the high abundance of tetrapyle octacantha acanthodesimia vinculata cladococcus cervicoris octopyle octospinosa spongaster tetras streblacantha circumtexta and spongotrochus glacialis the patterns of distribution and the abundances of the species botryocyrtis scutum pterocorys hertwigii collosphaera tuberosa and didymocyrtis tetrathalamus tetrathalamus suggested that western equatorial pacific waters did not yet influence the region at the time of sampling the first two species were dominant in the northern scs during our sampling the species cornutella profunda and cyrtopera laguncula were rare at depths of 150 250 m in the tropical region of the scs and assemblages in northern and southern scs were very similar the relative abundance of b scutum and p hertwigii is an indicator for seasonal changes in monsoonal circulation c 2008 elsevier b v all rights reserved

neogene paleoceanography of the eastern equatorial pacific based on the radiolarian record of iodp drill sites off costa rica fil sandoval maria i universidad de costa rica costa rica universite de lausanne suiza

predicting western north pacific ocean climate abstract it is shown that wintertime sea surface temperature anomalies in the confluence region of the kuroshio oyashio currents in the western north pacific can be skillfully predicted at lead times of up to 3 yr the predictions are based on the history of the wind stress over the north pacific and oceanic rossby wave dynamics the predictions may be exploitable in fisheries research and other ecological applications

an early holocene peak occurrence and recent distribution of rhizoplegma boreale radiolaria a biomarker in the norwegian sea abstract several sediment cores in the norwegian sea reveal in the early preboreal abundance peaks of up to 14 of rhizoplegma boreale cleve these peaks generally coincide with a transition from cold to warm water radiolarian assemblages and a high number of diatom valves chaetoceros sp indicating highly productive surface waters the r boreale peak represents an ecological event caused by an influx of north atlantic water and can potentially be used as a chrono stratigraphic marker within the eastern part of the norwegian sea in core hm 79 6 2 the r boreale peak reaches 9 2 and is found between two 14 c dated ash layers we estimated the age of the r boreale peak to be 9880 55 yr bp by linear interpolation between datum points the characteristic stratigraphical distribution of r boreale was used to establish a better age model for the studied section rhizoplegma boreale has been mapped in surface sediment samples from the iceland sea the norwegian sea and the norwegian fjords an oceanic form with six and a neritic form with eight radial spines were found in these areas recent distribution of rhizoplegma boreale is mainly confined to the nordic seas greenland iceland and norwegian seas the north pacific including the bering sea and sea of okhotsk and in the southern ocean the highest occurrence of r boreale is found in areas with high primary production and mixing of water masses

radiolarians under the seasonally sea ice covered conditions in the okhotsk sea flux and their implications for paleoceanography abstract four time series sediment traps at two stations and three piston cores from the okhotsk sea were quantitatively examined for coarse sized radiolarian shells 63 m traps were deployed at 300 m and 1550 m at station m4 53 01 n 145 30 e and at 300 m and 700 m at station m6 49 30 n 146 28 e during august 1998 through may 2000 the chronologies of the piston cores were established applying 18 o and paleomagnetic intensity variations they provide records extending back to marine isotope stage mis 5 51 the modern and past changes in radiolarian assemblages are associated with environmental and productivity changes radiolarian fluxes in the sediment traps exhibited significant summer to autumn flux peaks with suppressed values during the winter when sea ice covered the sea surface at the trap sites total radiolarian accumulation rate rar variations in each core tended to correspond to glacial interglacial cycles and increased during the last deglaciation in particular the temporal rar variation in core xp98 pc1 off kamchatka showed a similar trend with the climatic changes expressed by 18 o values during the glacial interglacial cycles for the last 125 kyr regional differences were also apparent rars showed extremely low values during 12 40 kyr and 63 70 kyr in core xp98 pc2 central okhotsk sea indicating the enhanced sea ice impact the sea ice coverage might have continued for a significant part of the year during the intervals since radiolarians did not appear to increase even during the summer to autumn rar variations in core xp98 pc4 off sakhalin showed higher values than xp98 pc2 during mis 2 and 4 thus in eastern sakhalin around site xp98 pc4 sea ice coverage might have been seasonal but not perennial even during mis 2 and 4 among the radiolarian taxa cycladophora davisiana was the most abundant species at the lower traps and in all cores the fluxes of c davisiana at lower traps showed much higher values than those of upper traps and also showed similar temporal patterns with the fluxes of aluminum and terrigenous materials therefore c davisiana fluxes may be associated with terrigenous organic materials increased nutrient supply from the continental shelves presumably transported by seasonal sea ice and released by sea ice melting might be mainly responsible for the high production of c davisiana in the okhotsk sea especially during the last deglaciation

a new coastal water radiolarian assemblage recovered from sediment samples from the antarctic ocean abstract the study of circum antarctic sediment samples from south of 60 s reveals the presence of a distinctive coastal assemblage in shallow waters around antarctica this assemblage consists primarily of just two species rhizoplegma boreale cleve and phormacantha hystrix cleve plectacantha oikiskos jorgensen group this assemblage resembles assemblages from norwegian fjords in both its taxonomic composition and low diversity it is distinguished from the typical open ocean antarctic assemblage with its high diversity the distribution of the coastal assemblage appears to be determined mainly by water depth or proximity to the coastline rather than temperature