Search

Climate changes over the past two millennia in the central part of the Gulf of St. Lawrence are documented in this paper with the aim of determining and understanding the natural climate variability and the impact of anthropogenic forcing at a regional scale. The palynological content (dinocysts, pollen, and spores) of the composite marine sediment core MSM46-03 collected in the Laurentian Channel was used to reconstruct oceanographic and climatic changes with a multidecadal temporal resolution. Sea-surface conditions, including summer salinity and temperature, sea-ice cover, and primary productivity, were reconstructed from dinocyst assemblages. Results revealed a remarkable cooling trend of about 4°C after 1230 cal yr BP (720 CE) and a culmination with a cold pulse dated to 170-40 cal yr BP (1780-1910 CE), which likely corresponds to the regional signal of the Little Ice Age. This cold interval was followed by a rapid warming of about 3°C. In the pollen assemblages, the decrease of Pinus abundance over the past 1700 yr suggests changes in wind regimes, likely resulting from increased southerly incursions of cold and dry Arctic air masses into southeastern Canada. [ABSTRACT FROM AUTHOR]

Abstract: Dinocysts occur in a wide range of environmental conditions, including polar areas. We review here their use for the reconstruction of paleo sea ice cover in such environments. In the Arctic Ocean and subarctic seas characterized by dense sea ice cover, Islandinium minutum, Islandinium? cezare, Echinidinium karaense, Polykrikos sp. var. Arctic, Spiniferites elongatus–frigidus and Impagidinium pallidum are common and often occur with more cosmopolitan taxa such as Operculodinium centrocarpum sensu Wall & Dale, cyst of Pentapharsodinium dalei and Brigantedinium spp. Canonical correspondence analyses conducted on dinocyst assemblages illustrate relationships with sea surface parameters such as salinity, temperature, and sea ice cover. The application of the modern analogue technique permits quantitative reconstruction of past sea ice cover, which is expressed in terms of seasonal extent of sea ice cover (months per year with more than 50% of sea ice concentration) or mean annual sea ice concentration (in tenths). The accuracy of reconstructions or root mean square error of prediction (RMSEP) is ±1.1 over 10, which corresponds to perennial sea ice. Such an error is close to the interannual variability (standard deviation) of observed sea ice cover. Mismatch between the time interval of instrumental data used as reference (1953–2000) and the time interval represented by dinocyst populations in surface sediment samples, which may cover decades if not centuries, is another source of error. Despite uncertainties, dinocyst assemblages are useful for making quantitative reconstruction of seasonal sea ice cover. [Copyright &y& Elsevier]

Abstract: A deep-sea sediment core covering the last 20ka and located between the Polar and the Arctic fronts in the marginal ice zone (MIZ) of the central Fram Strait has been investigated for changes in paleoceanography and calcium carbonate preservation. The reconstruction is based on the distribution patterns of planktic foraminifera, mean shell weight and the degree of fragmentation of their shells, stable isotopes and other geochemical and sedimentological data. The results show that the planktic foraminifera shells are poorly preserved throughout most of the record. Only the intervals comprising the early Holocene from 10.8 to ~8calka BP and the last 800yr show improved preservation of CaCO3. The dissolution correlated with the extent of Arctic water and the associated marginal ice zone (MIZ) and high organic productivity. Dissolution of planktic foraminifera is generally high during the late deglaciation, mid and late Holocene prior to ~800calyr BP. The abundance of small subpolar species increases in the surface sediments dating from the last century, which could be interpreted as a large and significant surface water warming. However, this apparent high-magnitude warming seems to be overestimated due to preservation changes in the youngest sediments. [Copyright &y& Elsevier]

Abstract: In order to explore the potential of dinocyst assemblages in marine sediment as a proxy for primary productivity, we analyzed a reference “modern” database including 1171 sites from the North Atlantic Ocean (n =483), the Arctic Ocean (n =401) and the North Pacific Ocean (n =287). We compiled two sets of primary productivity data derived from satellite observations: (1) The dataset from the Coastal Zone Color Scanner (CZCS) program applied to observations from 1978 to 1989 and (2) the data set from the MODerate resolution Imaging Spectroradiometer (MODIS) program using observations from 2002 to 2005. We performed canonical correspondence analysis (CCA) on a data matrix that included 62 dinocyst taxa and eight sea-surface parameters (winter and summer salinity, winter and summer temperature, sea-ice cover, summer, winter and annual primary productivity). CCA results show that primary productivity is a determinant parameter of dinocyst assemblages (including both phototrophic and heterotrophic taxa) in the North Atlantic, North Pacific, and at hemispheric scale. In the North Pacific, the relationship between productivity and dinocyst assemblages is particularly strong. We tested the modern analogue technique to reconstruct productivity using the North Atlantic, North Pacific, Arctic and hemispheric dinocyst data sets. With the exception of the Arctic Ocean alone, which is characterized by overall low productivity, productivity can be estimated with an accuracy (Root Mean Square Error=RMSE) of ±11–25%. The best performance is obtained for reconstruction of winter productivity from the MODIS data. It is noteworthy that the RMSE for all estimated productivity parameters is narrower than the mean differences between productivity data derived from the MODIS and CZCS data sets. Therefore, we conclude that dinocysts can be used to reconstruct productivity with an accuracy equivalent to that of primary productivity estimated from satellite observations. Application of the approach in a sedimentary core from the northwest North Atlantic (core HU 91-045-094) revealed large amplitude variations of productivity over the last 25,000 years. The use of both MODIS and CZCS datasets indicate generally low productivity during the glacial stage, the Younger Dryas and Heinrich events, with annual productivity of less than 100 gC m−2. The reconstructions also suggest higher productivity during the early Holocene, especially based on the MODIS data that suggest annual values of up to 350 gC m−2. [Copyright &y& Elsevier]

Abstract: Coccolith and dinoflagellate cyst (or dinocyst) population counts were compiled from existing surface sediment databases as well as new counts in order to establish an 87-sample database for which assemblages of both microfossil groups are known. This database allowed a direct comparison of the distribution of coccolith and dinocyst assemblages in the subtropical to subpolar North Atlantic. In addition, the relationship between these assemblages and sea surface environmental parameters was addressed, in order to identify possible differences in the ecology of the two plankton groups. The comparison highlights an excellent correspondence between dinocyst assemblages, coccolith assemblages and the distribution of the surface water masses represented in our database, notably in the subtropical and temperate domains. In the subpolar domain, coccolith assemblages are much less diversified than dinocyst assemblages in terms of species. As a result, the discrimination between the subpolar water masses based on coccolith assemblages is not as clear as in the subtropical/temperate regions, whereas dinocyst assemblages show a distribution pattern closely related with surface hydrography. Canonical correspondence analyses performed on coccolith and dinocyst assemblages show that sea surface temperature is the primary environmental parameter influencing the distribution of both groups. Dinocyst assemblages also seem to respond to the distance to the coast, and may therefore bring additional information compared with coccolith assemblages. Other significant environmental factors include sea surface salinity and productivity, but their relative importance changes depending on the inclusion of samples from extreme environmental settings in the database. Results suggest that the complexity of the interrelationships between the various environmental parameters makes it difficult to adequately bring to light all the different environments and their associated coccolith/dinocyst assemblages in multivariate analyses. However, each surface water mass represented in our database is characterized by a unique combination of environmental parameters as well as by distinct associations of coccolith and dinocyst assemblages, thus showing that these microfossil groups closely relate to sea surface conditions, including temperature, salinity and productivity. [Copyright &y& Elsevier]

Abstract: Fifty-six surface sediment samples from the northeastern Pacific (43–25°N) were investigated in order to examine the spatial distribution of modern organic-walled dinoflagellate cysts in relation to hydrological conditions and marine productivity. The analyzed dinoflagellate cyst assemblages are diverse, and include over 60 taxa. Multivariate statistical analysis (CCA) of dinoflagellate cysts and environmental variables identifies annual productivity and sea-surface temperature as main factors affecting dinoflagellate cyst distribution in the region. In the studied area, marine productivity is greatly influenced by the strength of the coastal upwelling. Cyst assemblages from the coastal sites associated with active upwelling are characterized by the dominance of heterotrophic taxa, particularly Brigantedinium spp., Echinidinium spp. and cysts of Protoperidinium americanum. Taxa associated with low productivity offshore sites are Impagidinium spp., Nematosphaeropsis labyrinthus, Pyxidinopsis reticulata and Operculodinium centrocarpum. Dinoflagellate cyst species associated with warmer waters are Lingulodinium machaerophorum, Spiniferites mirabilis, S. ramosus, S. delicatus/bulloideus, Bitectatodinium spongium and Polykrikos cf. kofoidii, while those from cooler environments include Selenopemphix nephroides, Trinovantedinium variable and cysts of Pentapharsodinium dalei. Combining the present cyst dataset with other published cyst data from the Northeastern Pacific, we have compiled a “NE Pacific 188” database. This database can be used as a basis for the quantitative reconstructions of (paleo)temperature and productivity in the Northeastern Pacific. [Copyright &y& Elsevier]

The response of the Greenland ice sheet to global warming is a source of concern notably because of its potential contribution to changes in the sea level. We demonstrated the natural vulnerability of the ice sheet by using pollen records from marine sediment off southwest Greenland that indicate important changes of the vegetation in Greenland over the past million years. The vegetation that developed over southern Greenland during the last interglacial period is consistent with model experiments, suggesting a reduced volume of the Greenland ice sheet. Abundant spruce pollen indicates that boreal coniferous forest developed some 400,000 years ago during the "warm" interval of marine isotope stage 11, providing a time frame for the development and decline of boreal ecosystems over a nearly ice-free Greenland. [ABSTRACT FROM AUTHOR]

Seventy-six surface marine sediment samples from the northwest margin of North America, between 40°N and 60°N, were analysed for their palynological content in order to document the regional distribution of dinocyst assemblages and their relationships with environmental conditions (sea-surface temperature and salinity, productivity and upwelling). The results illustrate a high concentration of dinocysts, notably in the neritic area (up to 34 000 cysts cm−3) and a relatively high species diversity with 32 taxa identified. The assemblages include cysts of both autotrophic and heterotrophic species. Brigantedinium spp. accompanied by other heterotrophic taxa such as Votadinium spp., Quinquecuspis concreta, Trinovantedinium variabile and Lejeunecysta spp. dominate in the nearshore areas influenced by seasonal upwelling. The offshore sites are dominated by autotrophic taxa represented mainly by Operculodinium centrocarpum, Pyxidinopsis reticulata, Nematosphaeropsis labyrinthus and Impagidinium aculeatum in the south, and by O. centrocarpum, Pentapharsodinium dalei, Spiniferites ramosus and Spiniferites elongatus in the Gulf of Alaska. Principal component analysis demonstrates that the regional distribution of dinocyst assemblages is controlled by the primary productivity and upwelling, and by the winter temperature gradient. [Copyright &y& Elsevier]

Dinosterol (4α,23,24-trimethyl-5α-cholest-22E-en-3β-ol) is frequently used as an alternative to dinoflagellate cyst (dinocyst) counting in paleoceanography to assess dinoflagellate inputs to marine sediments. However, recent studies have shown poor correlation between these two proxies in continental-margin sediments. We reevaluated the relationship and expanded it to include a suite of biogeochemical transformation products of the parent dinosterol (dinosterone, dinostanone, and dinostanol). These dinoflagellate-specific 4α,23,24-trimethyl steroidal species (Σdinosterol) are compared to dinocyst counts in sediments from the western Mexican margin (375-3,500 m). Samples were taken from subsurface (3-6 cm) and down core (16-27 cm) to reflect widely contrasting organic carbon content and redox conditions. A strong correlation was found between the sum of all dinoflagellate-derived sterols, Σdinosterols, and total dinocyst counts, highlighting the importance of including diagenetic alteration products of the parent molecule when exploiting organic biomarkers in paleoceanographic studies. In low-energy environments and for well-preserved samples, such as those studied in this work, both methods provide robust, internally consistent data, suggesting that when diagenetic transformation products of dinosterol are taken into account, gas chromatography and optical microscopy could be used interchangeably to estimate dinoflagellate inputs to marine sediments. [ABSTRACT FROM AUTHOR]

Abstract: Proxy evidence suggests that a mean atmospheric state, reminiscent of the positive phase of the North Atlantic/Arctic Oscillation (NAO), persisted throughout the early Holocene and resulted in a dipole pattern in sea-ice concentration between the north-eastern and north-western North Atlantic. A dynamic thermodynamic coupled sea-ice–ocean model is used to simulate the sea-ice concentration and thickness in the Arctic during the early Holocene. It is forced with winds, ocean currents and surface air temperatures (SAT) from recent years with a positive phase of the NAO in conjunction with altered long and shortwave radiation and surface air/ocean temperatures. The simulation reproduces an east/west dipole in sea-ice cover of the Arctic and is compatible with reconstructed sea-ice conditions in the Chukchi Sea (inferred from dinoflagellate cyst analysis of ocean sediment cores). Sensitivity studies were performed to investigate the individual effects of radiation, ocean forcing, SAT and winds on sea-ice cover. Results show that in the East Siberian Sea, SAT is the dominant forcing for changes in sea-ice thickness, whereas winds and SAT are the dominant factors in sea-ice concentration anomalies. In the Barents Sea, sea-ice anomalies are influenced by air and sea surface temperatures, and ocean currents. [ABSTRACT FROM AUTHOR]

Abstract: A series of cores (box and piston) were collected at 2 key locations in Lancaster Sound (cores 2004-804-009 BC and PC) and Barrow Strait (cores 2005-804-004 BC and PC) in the Canadian Arctic Archipelago to document the evolution of sea-surface conditions in the main axis of the Northwest Passage during the Holocene time period. Reconstruction of sea-surface parameters (summer temperature and salinity, duration of sea-ice cover) were estimated based on transfer functions using dinoflagellate cyst assemblages as proxy indicators. The chronology of these cores is based on calibrated AMS-14C dates, 210Pb analyses, and correlations between paleomagnetic secular variations of the geomagnetic field and a predicted spherical harmonic model of the geomagnetic field (CALS7 K.2). Our age models for both cores indicate that 009 PC spans the last 11,100 cal BP, while 004 PC encompasses the last 10,800 cal BP. Calculated sedimentation rates are in the range of 43–140 cm/kyr for core 009 PC and 15–118 cm/kyr for core 004 PC, allowing for a millennial time scale resolution in each core. Our results indicate relatively harsh conditions in Lancaster Sound between 10,800 and 9000 cal BP (summer temperatures 2 °C cooler than at present), which we associate with the presence of active ice-streams in northernmost Baffin Bay and a weak West Greenland Current. This is followed by a warming trend (up to 3 °C higher than present) that took place between ∼8500 and 5500 cal BP, which we associate with the Holocene thermal maximum and to a large scale atmospheric pattern such as the Arctic Oscillation operating at the millennial time scale. This is concomitant with an increase in the relative abundance of phototrophic dinoflagellate cyst taxa. A gradual cooling of sea-surface temperature and increased sea-ice follow this from 5500 cal BP until the modern period. In Barrow Strait, harsh sea-surface conditions prevailed from 11,100 to 5500 cal BP, with summer temperatures as low as 4 °C cooler than at present. The warming trend occurred later in this region (between 5500 and ∼1000 cal BP), after which a gradual cooling is observed until the modern period. The apparent shift, or opposite warming trends, between Lancaster Sound and Barrow Strait after 5500 cal BP could be the result of a change in atmospheric circulation patterns related to a possible shift in the AO mode (from AO+ to AO−). Comparison of ice core δ18O record from Devon Island ice cap and the reconstructed sea-surface temperature from core 009 PC suggests a strong atmospheric-oceanic coupling throughout the Holocene in this area. [Copyright &y& Elsevier]

The Arctic is experiencing a greater-than-average response to anthropogenically induced climate change. Arctic marine ecosystems are known to react quickly to changing environmental conditions and the ongoing climate change will likely affect the Arctic marine carbon cycle. A possible approach to predict future changes in the Arctic marine carbon cycle is by investigating its past variability. However, quantification of the reaction of the individual components of the marine carbon cycle to global change in the past is hampered by the difficulty to separate the bioproductivity signal in marine sediments from diagenetic processes as well as the difficulty to reconstruct past primary productivity independent of other environmental forcings. Here we make use of the observations that the composition of marine plankton communities reflects the trophic regime under which they grew and that this information is transferred into the sediment by their fossils and that organic-walled dinoflagellate cysts (dinocysts) are in general not, like calcareous and siliceous remains, susceptible to dissolution at high latitudes. Our specific aim is to advance the quantification of primary productivity reconstruction for the Arctic and Subarctic Baffin Bay region by calibrating regional transfer functions evaluated by a rigorous statistical analysis of the relationship between assemblage data and multiple candidate controlling parameters. The choice to calibrate regionally is guided by the hypothesis that such calibration will minimise the effect of nuisance variables and complex ecological relationships observed in a global calibration. We begin by carrying out an objective variable selection guided by canonical ordination, revealing that the regional dinocyst dataset contains multiple mutually independent environmental gradients, including productivity. We then use the dataset to design regional transfer functions and test their ability to interpret assemblage changes recorded in Holocene sediments by their applications on four records covering a north-south transect throughout the Baffin Bay. We specifically focus on Holocene sections, assuming that the magnitude of environmental change in the Holocene was small and the regional calibration is sufficient to capture the range of past environments recorded in the cores. To estimate the significance of the reconstructions we evaluate if the reconstructed primary productivity explains more of the variation in the fossil data than random environmental variables assigned to the same fossil data. This analysis indicates that in each of the cores the environmental change to which the dinocysts reacted correspond to changes in different oceanographic parameters and that the statistical significance of the reconstructions depends on the calibration techniques used. These results imply that the existence of multiple environmental factors independently affecting the dinocyst assemblage composition requires a rigorous test of which of these parameters were likely changing in the past, before the transfer functions can be interpreted. [ABSTRACT FROM AUTHOR]

Abstract: Recent studies have correlated dinoflagellate resting cyst morphology to salinity and density variations in the water column, suggesting that morphology can be used for paleoceanographic reconstructions. However, the univariate statistics used by these studies are appropriate only where morphology is related to a single variable. Density is a function of salinity and temperature, so more advanced statistical methods are needed to understand which parameters affect morphology. In this study based on surface (coretop) sediments, a set of environmental variables (sea-surface salinity, temperature, nitrate, and phosphate) was simultaneously correlated to morphological variations seen in resting cysts produced by the dinoflagellate Protoceratium reticulatum (= Operculodinium centrocarpum sensu Wall and Dale). Approximately 3200 measurements were obtained from the North Atlantic Ocean and used to generate a working model based on the Akaike information criterion. Hierarchical partitioning was then applied to establish the independent and joint effects for each predictor variable. Results from these analyses showed that while salinity constitutes the dominant variable affecting process length in the cysts of P. reticulatum in the North Atlantic, it is not the sole explanatory variable and that multicollinearity exists. Temperature and nutrients also showed a significant relationship to the morphology, requiring multiple regression to construct a representative model. The applicability of the North Atlantic working model was finally evaluated by comparing the results to data from the Mediterranean, Marmara, and Black seas, and Baltic–Kattegat–Skagerrak estuarine system. This comparison showed regional differences in morphological–environmental correlation. While salinity constitutes the most important explanatory factor in both the North Atlantic and Baltic–Skagerrak system, this is not so for the Mediterranean–Black Sea region where temperature is the dominant variable. It is concluded that a predictive salinity model based on P. reticulatum cyst morphology has at best a regional application. [Copyright &y& Elsevier]

Abstract: Geological records of past sea ice, such as those contained in Arctic marine sediments, offer an opportunity to strengthen our understanding of long-term sea ice variability, provided unambiguous paleo-sea ice proxies can be developed. One such recently proposed proxy is IP25, a highly branched isoprenoid alkene biosynthesized exclusively by sea-ice dwelling diatoms (Haslea spp.), which is well preserved in marine sediments and could be used to reconstruct past changes in spring sea-ice extent. However, little is known about regional-scale controls on IP25 production in sea ice, limiting its wider applicability as a paleo-sea-ice proxy. To address this issue we examined the distributions of IP25 and the marine productivity biomarkers dinosterol and brassicasterol in a suite of surface sediment samples distributed across the Arctic. We find a statistically significant, logarithmic relationship between IP25 and spring sea ice cover in sediment samples from arctic and subarctic sites in the Pacific (n = 96, R 2 = 0.67, P < 0.0001) and the Atlantic n = 25, R 2 = 0.50, P < 0.0001), though the absolute concentrations of IP25 are generally higher in the Atlantic (1.6–166.4 μg/g OC) than in the Pacific (0–38.5 μg/g OC) for equivalent sea-ice cover, and there are regional and basin-specific differences in the slope of the IP25 – sea ice relationship. Using the PDIP25 index, which also includes a biomarker for marine productivity (e.g., dinosterol) the relationship with sea ice cover is improved in all of the study areas (R 2 = 0.86 and R 2 = 0.75 for Atlantic and Pacific, respectively) and most basin specific differences in the proxy–sea ice relationships are significantly reduced. However, there remain differences in the absolute magnitudes of the PDIP25 index for equivalent amounts of sea ice cover between the Atlantic and the Pacific, and with previously published data from Fram Strait. Nevertheless, this work demonstrates that the PDIP25 index can provide a valuable tool for sea ice reconstructions at local and regional scales. [Copyright &y& Elsevier]

Abstract: In this study, we explore the relationship between the modern assemblages of organic-walled dinoflagellate cysts and sea-surface conditions (temperature, salinity, primary productivity) and water depth and distance to the coast. Statistical treatments were performed on 95 surface sediment samples from sites located along the south-western Mexican coast (14.76° N to 24.75°N). Redundancy analysis (RDA) illustrates that the principal parameters correlated with the regional cyst distribution are the distance to the coast and the productivity in the upper water column, which is closely related to upwelling intensity. Empirical observations coupled with RDA provide insight into the spatial coverage of some cyst taxa produced by dinoflagellate species potentially responsible for harmful algal blooms along the coast. They also allow the recognition of four zones of assemblages, which are linked to the upwelling intensity and the productivity and characterize La Paz Bay, the south-western Mexican margin (from 15.95° N to 23.11° N), the northern part of the Gulf of Tehuantepec and the southern part of the Gulf of Tehuantepec. [ABSTRACT FROM AUTHOR]

Abstract: Absolute abundances (concentrations) of dinoflagellate cysts are often determined through the addition of Lycopodium clavatum marker-grains as a spike to a sample before palynological processing. An inter-laboratory calibration exercise was set up in order to test the comparability of results obtained in different laboratories, each using its own preparation method. Each of the 23 laboratories received the same amount of homogenized splits of four Quaternary sediment samples. The samples originate from different localities and consisted of a variety of lithologies. Dinoflagellate cysts were extracted and counted, and relative and absolute abundances were calculated. The relative abundances proved to be fairly reproducible, notwithstanding a need for taxonomic calibration. By contrast, excessive loss of Lycopodium spores during sample preparation resulted in non-reproducibility of absolute abundances. Use of oxidation, KOH, warm acids, acetolysis, mesh sizes larger than 15 µm and long ultrasonication (>1 min) must be avoided to determine reproducible absolute abundances. The results of this work therefore indicate that the dinoflagellate cyst worker should make a choice between using the proposed standard method which circumvents critical steps, adding Lycopodium tablets at the end of the preparation and using an alternative method. [Copyright &y& Elsevier]

Organic-walled resting cysts of planktonic dinoflagellates occur commonly in modern marine sediment where they represent, with rare exceptions, the only geologically preservable part of the life cycle. Although many species do not produce fossilizable resting cysts, upper Quaternary sediments contain a diverse cyst record that is used frequently for paleoenvironmental reconstruction and stratigraphic analysis. Reconstructions of past sea-surface conditions rely on an understanding of the distributions of dinoflagellate cysts in modern sediments linked to their respective environmental parameters, underpinned by sound taxonomy and standardized nomenclature. Stratigraphic studies additionally require knowledge of morphological details to distinguish extant from similar extinct taxa. Here, 51 dinoflagellate cyst species and two informal cyst morphotypes that are commonly encountered during routine palynological analysis of upper Quaternary marine sediments from the Northern Hemisphere are briefly described taxonomically and illustrated. In addition, their lowest stratigraphic occurrences are provided. • 51 common extant dinoflagellate cyst species and two morphotypes are briefly described and illustrated. • 2 belong to the Gymnodiniales, 30 to the Gonyaulacales and 21 to the Peridiniales. • their lowest stratigraphic occurrences are provided. [ABSTRACT FROM AUTHOR]

The subpolar gyre (SPG) is a major feature controlling climate and ocean circulation of North Atlantic region, with significant variability of cold and warm ocean currents feeding into the gyre. The western sector of the SPG, the Labrador Sea, is a major deep water formation site, thus also directly influencing the Atlantic Meridional Overturning Circulation (AMOC). Here we compare records of SPG circulation from selected sites off south Iceland, west and southeast Greenland and Newfoundland in order to establish a combined record of SPG circulation through the Holocene. Our records combine multi-proxy studies (foraminifera, diatoms, dinoflagellate cysts, sediment properties, biomarkers, elemental composition and environmental magnetics) from a range of marine sediment cores to test for large-scale changes in ocean circulation in the Holocene. The SPG region has experienced several major changes in ocean circulation, with a major reorganisation occurring during the deglaciation and again at approximately 7.5 kyr BP and 3-4 kyr BP. Especially during the late Holocene, climatic conditions were largely antiphase in the Labrador Sea to the general North Atlantic region climate due to influence of the Northern Annular Mode affecting the strength of the Atlantic component of the West Greenland Current as well as the flow of the Labrador Current. This again influenced the strength and expansion of the SPG and exemplifies that the SPG has undergone significant variability at multi-decadal to millennial time scales during the Holocene. [ABSTRACT FROM AUTHOR]