deposition and modification of a flood layer on the northern california shelf lessons from and about the fate of terrestrial particulate organic carbon the 1995 flood of the eel river in northern california provided an opportunity to follow the short term history of riverine particulate matter on a continental shelf particulate organic carbon including both vascular plant debris and soil carbon was utilized as a tracer of the distribution and modification of the shelf flood deposit these components were sorted during initial emplacement of the deposit both in the river plume and in the benthic boundary layer during the 8 months following the flood lateral transport shallow burial and bioturbation contributed to spatial changes in the amount and character of carbon in the flood deposit study of the deposit suggests that this and previous flood layers may be preserved in the shelf and upper slope stratigraphic record as clay rich beds with relatively high carbon to nitrogen ratios and more negative 13c values than background non flood sediment concentrations of vascular plant debris are locally characteristic of such layers and may serve as distinctive stratigraphic markers investigation of organic carbon in the 1995 flood layer on the eel river shelf provides insight into the fate of terrestrial particulate carbon on continental margins in general flooding of the eel river and of similar river systems draining mountainous terrains introduces large quantities of terrestrial carbon to the marine environment and may favor the preservation of both terrestrial and marine carbon the abundant woody vascular plant debris discharged during floods is especially likely to survive oxidation and sulfate reduction in the shallower zones of the seabed this study reveals the dominant role that physical and biological processes may play in attenuating the terrestrial organic carbon signal on shelves over monthly to yearly time scales

a distributed temperature index ice and snowmelt model including potential direct solar radiation hourly melt and discharge of storglaciaren a small glacier in sweden were computed for two melt seasons applying temperature index methods to a 30 m resolution grid for the melt component the classical degree day method yielded a good simulation of the seasonal patient of discharge but the pronounced melt induced daily discharge cycles were not captured modelled degree day factors calculated for every hour and each gridcell from melt obtained from a distributed energy balance model varied substantially both diurnally and spatially a new distributed temperature index model is suggested attempting to capture both the pronounced diurnal melt cycles and the spatial variations in melt due to the effects of surrounding topography this is accomplished by including a radiation index in terms of potential clear sky direct solar radiation and thus without the need for other data besides air temperature this approach improved considerably the simulation of diurnal discharge fluctuations and yielded a more realistic spatial distribution of melt rates the incorporation of measured global radiation to account for the reduction in direct solar radiation due to cloudiness did not lead to additional improvement in model performance

geochemical and sedimentological considerations of a permanently anoxic fjord framvaren south norway abstract framvaren a fjord in south norway is an example of extreme anoxia due to the geomorphological features sill depth 2 m basin depth 180 m the postglacial history of framvaren is outlined emphasizing the preservation of environmental changes in the properties of the water and the sediments high levels of hydrogen sulfide in the water 170 180 ml l 1 or 7 8 mm h 2 s dense populations of photosynthetic bacteria at the redox boundary total number 3 10 6 ml 1 metal sulfide formation in the anoxic water e g framboidal pyrite and zinc sulfide and organic rich bottom sediments with high metal content e g 1000 ppm zn are typical examples the rate of sedimentation is estimated in three independent ways suggesting an average annual flux of 100 g m 2 yr 1 in the central basin of framvaren fluxes of organic matter and zinc to the sediments are calculated and compared with potential sources

sedimentary nitrogen isotopic ratio as a recorder for surface ocean nitrate utilization in two contrasting regions of the ocean the equatorial pacific and the southern ocean the 15n of core top sediments were strongly related to no3 in surface waters with distance from the equator in the equatorial pacific 15n increased from 7 to 16 as no3 decreased from 8 m to 0 1 m going from 60 to 30 s in the se indian ocean core top 15n increased from 5 to 11 as surface no3 decreased from 25 m to 0 1 m these results are strong evidence that sedimentary 15n in these regions is recording the increasing isotopic enrichment of near surface no3 with its depletion by phytoplankton in the case of the equatorial pacific 15n values for sinking particles collected at 150 m matched well the core top sediment values demonstrating little diagenetic alteration of the near surface generated isotopic signal these equatorial pacific data sets have variations with near surface no3 consistent with rayleigh fractionation kinetics for a fractionation factor u of 2 5 this value is substantially lower than previously found for temperate or polar regions perhaps as a result of differences in phytoplankton species assemblage or growth condition in the southern ocean south of the polar front comparison of 15n values for opal rich sediments south and sinking particles indicates an apparent 5 diagenetic enrichment relative to the surface generated signal that requires further investigation this exception aside our observations show that the surface water relationship of increasing 15n with increasing no3 depletion is generally transmitted to and preserved in the sediments an important requirement for further development and application of this important paleoceanographic tool

positive degree day factors for ablation on the greenland ice sheet studied by energy balance modelling ice ablation is related to air temperature by the positive degree day factor variations of the positive degree day factor in west greenland are studied using an energy balance model to simulate ablation under different conditions degree day factors for simulated and measured ice ablation at nordbogletscher and qaman rssup sermia agree well with values around 8 mm d 1 c 1 degree day factors for snow are less than half those for ice energy balance modelling shows that degree day factors vary with summer mean temperature surface albedo and turbulence but there is only evidence of large positive degree day factors at lower temperatures and with low albedo 0 3 the greatest effect of albedo variations 0 3 0 7 is at lower temperatures while variations in turbulence have greater effect at higher temperatures current models may underestimate runoff from the greenland ice sheet by several tenths because they use a degree day factor for melting ice that is too small for the colder parts of the ice sheet i e the upper ablation area and the northerly margin

recent fluctuations of meteorological and snow conditions in japanese mountains meteorological data from mountainous areas of japan have been collected by the national research institute for earth science and disaster prevention nied for almost 20 years the collected long period data indicate that neither a notable increase in mean winter temperature nor a reduction in snow depth has occurred in these areas the maximum snow depth sdmax and maximum snow water equivalent swemax show similar fluctuation trends although with large year to year variations in value and a larger fluctuation range for swemax than for sdmax this result suggests that monitoring of only sdmax in mountainous areas is not sufficient for understanding the quantitative fluctuation of water resources originating from snow the sdmax fluctuation trends in mountainous areas sometimes differ from those in flatland areas because mountain sdmax depends more on winter precipitation than on mean winter air temperature whereas the opposite is true for flatlands in addition the dependence ratio of sdmax on fluctuations in winter precipitation changes with altitude because the distributions of precipitation with air temperature change with altitude

stable oxygen and carbon isotope information on the establishment of a new opportunistic foraminiferal fauna in a swedish skagerrak fjord basin in 1979 1980 significant faunal changes reported fromrecent coastal environments which are not directly influenced by urban and industrial impact are rarely seen in gullmar fjord on the swedish west coast a significant foraminiferal fauna change occurred in connectionwith severe low oxygen conditions that evolved in thewinter of 1979 1980 a foraminiferal fauna marked by common skagerrak kattegat species which had previously characterised the deep fjord basin was replaced by the opportunistic low oxygen tolerant species stainforthia fusiformis williamsson to study this phenomenon further we performed stable oxygen and carbon isotope analyses on the indicator species itself s fusiformis both on specimens from sediment cores representing approximately the last 85 years and on living stained individuals taken from a transect across the deep fjord basin our purpose was to detail how and why s fusiformis came to dominate the fauna the oxygen isotope results suggest that salinities and temperatures in the deep basin have been relatively constant over the last c 85 years while the carbon isotopes show a significant change towards more negative values in association with the faunal shift of 1979 1980 the combined results from both the cores and the surface sediments suggest that s fusiformis did not inhabit the deep basin until 1980 before then almost all specimens of s fusiformis were small sized and their carbon isotope values suggest they were re deposited shallow water specimens that had been transported down to the central deep basin as part of a suspension load after a major faunal extinction in 1979 1980 s fusiformis of all sizes suddenly appeared in large numbers and their carbon isotopic values were similar to the signal from registered in the recent living fauna within the deep basin this suggests that the opportunistic s fusiformis established itself in the deep basin as a consequence of the severe low oxygen event and the faunal crash of the previously dominating skagerrak kattegat fauna less

climate induced changes in sedimentary regimes for organic matter supply on the continental shelf off northern norway abstract with this study i suggest that changes in biogeochemical processes in northern norwegian fjords during the last glacial interglacial transition 14 3 to 6 3 ka b p are predominantly climate induced variable strength in atlantic water inflow intrusion of arctic waters and sea ice coverage various nutrient supply as well as several re advances of continental ice sheets are recorded by both bulk organic and selected biomarkers in sediments of the andfjord stable isotope 13corg 15n and rock eval pyrolysis data indicate a strong supply of terrestrial organic matter during stadials e g younger dryas older dryas whereas enhanced input of marine organic matter prevailed during the interstadials bolling allerod profiles of selected biomarkers of marine origin show a characteristic climate induced variation during the whole time interval where relatively low concentrations of dinosterols and c37 alkenones may indicate similar to today a minor contribution of their respective plankton groups coccolithophorids dinoflagellates the prevalence of arctic waters and seasonal sea ice coverage during the younger dryas is indicated by a single maximum of 24 methylenecholesterol probably indicating the dominance of sea ice diatoms and or the prevalence of diatoms of thalassiosiraceae in surface waters the sediments of the allerod in contrast show a pronounced maximum in dinosterols indicating a better adaptation of dinoflagellates to an oceanic regime that is characterized by incipient intrusion of atlantic water highly variable sea surface temperatures and well stratified water masses the concentration of higher molecular weight n alkanes however follows the deglacial early holocene trend of climate amelioration from the last deglaciation to the middle holocene with maxima during ice advances stadials and minima during the middle holocene warm period these new results significantly improve the understanding of climate induced response on organic matter supply in fjords and provide a better knowledge of past variations of biogeochemical processes in high latitude coastal environments

burial of terrestrial organic matter in marine sediments a re assessment 1 calculations based on recent observations indicate that approximately one third of the organic matter presently being buried in marine sediments may be of terrestrial origin with the majority of this terrestrial organic matter tom burial occurring in muddy deltaic sediments these calculations further suggest that the remineralization of terrestrial organic matter in the oceans is also much less efficient than that of marine organic matter these two underappreciated observations have important implications in terms of our understanding of the controls on the global carbon cycle from a paleoceanographic perspective the results presented here also suggest that changes in tom burial on glacial interglacial timescales have the potential to impact the global carbon cycle i e atmospheric co2 levels

sedimentary organic matter geochemistry of clayoquot sound vancouver island british columbia surface sediment samples from three interconnected fjords of clayoquot sound british columbia were density fractionated 1 6 g cm 3 to isolate discrete organic debris od from mineral associated organic matter mom total organic carbon oc values varied greatly ranging from 0 1 to 8 8 by weight with a general decreasing trend from fjord head to the continental shelf within the sediment terrestrial om was present either as vascular plant debris or soil mom down fjord the woody vascular plant material in the od fraction acquires nitrogen which is hypothesized to be due to the bacterial incorporation of nitrogen from the water terrestrial oc in the mom is incompletely replaced by marine oc within the fjords resulting in a 65 net loss of mom sediments deposited under oxic and intermittently anoxic water column conditions have organic carbon to surface area ratios oc sa ranging from 0 4 to 1 2 mg c m 2 similar to that of typical continental margin sediments given that temperate fjords contain an estimated 12 of the continental margin sediment deposited during the last 100 000 yr and that they bury at least a margin equivalent amount of oc either weight or surface area normalized we hypothesize that temperate fjords may contain 12 or more of the sedimentary oc buried during this time

a review of nitrogen isotopic alteration in marine sediments key points use of sedimentary nitrogen isotopes is examined on average sediment 15n 14n increases approx 2 per mil during early burial isotopic alteration scales with water depth abstract nitrogen isotopes are an important tool for evaluating past biogeochemical cycling from the paleoceanographic record however bulk sedimentary nitrogen isotope ratios which can be determined routinely and at minimal cost may be altered during burial and early sedimentary diagenesis particularly outside of continental margin settings the causes and detailed mechanisms of isotopic alteration are still under investigation case studies of the mediterranean and south china seas underscore the complexities of investigating isotopic alteration in an effort to evaluate the evidence for alteration of the sedimentary n isotopic signal and try to quantify the net effect we have compiled and compared data demonstrating alteration from the published literature a 100 point comparison of sediment trap and surface sedimentary nitrogen isotope values demonstrates that at sites located off of the continental margins an increase in sediment 15n 14n occurs during early burial likely at the seafloor the extent of isotopic alteration appears to be a function of water depth depth related differences in oxygen exposure time at the seafloor are likely the dominant control on the extent of n isotopic alteration moreover the compiled data suggest that the degree of alteration is likely to be uniform through time at most sites so that bulk sedimentary isotope records likely provide a good means for evaluating relative changes in the global n cycle

the vestfjorden traenadjupet palaeo ice stream drainage system mid norwegian continental shelf abstract an ice stream in the vestfjorden traenadjupet depressions off northern norway transported glacial debris to the shelf edge and into the deep sea during the last glaciation our interpretation is based mainly on regional and detailed bathymetry and 2d and 3d seismic data this palaeo ice stream was approximately 400 km long and covered an area of 20 000 km 2 including a complex system of tributary fjords and valleys in nordland county the drainage basin had an area of ca 150 000 km 2 within the fennoscandian ice sheet fis during the last glacial maximum lgm the location of the palaeo ice stream prevented large ice masses from reaching the montainous areas of lofoten and vesteralen a local ice dome was established in these areas the palaeo ice stream eroded extensively into both mesozoic and cenozoic sedimentary rocks and quaternary sediments a pattern of well developed subglacial sedimentary bedforms was produced e g mega scale lineations drumlins ice stream shear margin moraines are located on both sides of traenadjupet defining the width of the palaeo ice stream 90 km at the shelf edge these moraines are commonly 10 20 m high a few kilometres wide and reach several tens of kilometres in length a large recessional moraine the tennholmen ridge has been mapped in vestfjorden it is 80 m high 20 km wide and 60 km long we have interpreted this ridge as a grounding line moraine formed during a halt or a readvance of the ice stream during the last deglaciation the large transport of glacial debris towards the grounding line occurred during this stage northeast of the tennholmen ridge several smaller moraine ridges were developed at still stands during deglaciation

quantifying the contribution of glacier meltwater in the expansion of the largest lake in tibet lake siling co is currently the largest endorheic lake in tibet and the lake surface area has expanded by about 40 since the 1970s with a remarkable acceleration after 1999 in this study a hydrologic modeling framework was established by linking the variable infiltration capacity vic land surface hydrologic model with the degree day glacier melt model over the lake siling co basin with an aim to quantify the contribution of each runoff component to changes in the lake storage we found that glacier melt contributed to less than 10 of the total water input to the lake during 1979 2013 while precipitation induced runoff in nonglacierized area was responsible for about 67 75 the mean annual water input to the lake increased by 2 15x10 9 m 3 yr 1 in 2000 2013 relative to that in 1979 1999 the amount of precipitation over the lake surface precipitation induced runoff and glacier melt runoff accounted for 13 82 and 5 of this total increase respectively suggesting that the substantial expansion of siling co in the 2000s was mostly due to the increase in precipitation induced runoff when modeling lake level changes during 1979 2013 we found that the water level rose by 14 1m when glacier melt was included and by only 10 5m a reduction of about one fourth when glacier melt was removed it is concluded that glacier melt played an important role in controlling the water level of siling co although it only contributed less than 10 of water input to the lake during 1979 2013

carbon cycling and burial in new zealand s fjords understanding carbon cycling in continental margin settings is critical for constraining the global carbon cycle here we apply a multiproxy geochemical approach to evaluate regional carbon cycle dynamics in six new zealand fjords using carbon and nitrogen concentrations and isotopes lipid biomarkers and redox sensitive element concentrations we show that the new zealand fjords have carbon rich surface sediments in basins that promote long term storage i e semirestricted basins with sediment accumulation rates of up to 4 mm yr 1 using 13c distributions to develop a mixing model we find that organic carbon in fjord sediments is well mixed from marine and terrestrial sources in down fjord gradients this is driven by high regional precipitation rates of 6 m yr 1 which promote carbon accumulation in fjord basins through terrestrial runoff in addition we have identified at least two euxinic subbasins based on uranium molybdenum iron and cadmium enrichment that contain 7 organic carbon because the strength and position of the southern hemisphere westerly winds control precipitation and fjord circulation carbon delivery and storage in the region are intimately linked to westerly wind variability we estimate that the fjord region 759 km2 may be exporting up to 1 4 107 kgc yr 1 outpacing other types of continental margins in rates of carbon burial by up to 3 orders of magnitude

high correlation between winter precipitation and air temperature in heavy snowfall areas in japan long term data of winter air temperature and precipitation were analyzed and the correlation between them investigated in order to identify the factors influencing snow reduction during the recent warmer winters in the heavy snowfall areas in japan a high negative correlation between winter precipitation and air temperature was identified in the heavy snowfall areas on the sea of japan side in the center of the main island honshu it was confirmed that precipitation is mainly caused by cold winter monsoons and thus correlates to a large extent with air temperature in these areas the precipitation decrease can be considered an effective factor for the recent reduction in snow as well as the snowfall to precipitation ratio this should be taken into account for a better prediction of snow reduction in relation to global warming

factors controlling 13c contents of sedimentary organic compounds principles and evidence the carbon isotopic composition of any naturally synthesized organic compound depends on 1 the carbon source utilized 2 isotope effects associated with assimilation of carbon by the producing organism 3 isotope effects associated with metabolism and biosynthesis and 4 cellular carbon budgets these factors are reviewed and quantitative considerations summarized particularly with regard to active and passive modes of carbon assimilation by phytoplankton and the existence of discernible regularities in isotope effects associated with lipid biosynthesis it is concluded that n alkyl lipids are in general depleted in 13c by about 1 5 relative to polyisoprenoid lipids produced by the same organism the effects of biological reworking on isotopic compositions of organic carbon are examined and it is suggested that enrichment of 13c in sedimentary organic carbon may result from loss of ch4 from zooplanktonic gut communities isotopic methods for estimation of ancient co2 levels are considered and a hyperbolic form favored for the relationship between concentrations of dissolved co2 and isotopic fractionation

geochemical expressions of anoxic conditions in nordasvannet a land locked fjord in western norway abstract the nordasvannet fjord in western norway is a modern semi enclosed basin suitable for studying sedimentary cycles as they occur under anoxic bottom conditions it is characterized by strongly anoxic conditions in the water column and bottom sediments diagenetic pyrite formation occurs in the sediments and syngenetic pyrite is formed in the lower water column organic matter burial in the fjord exceeds that of other environments with normal marine or upwelling conditions this is due to the better preservation of organic matter organic matter composition appears to have changed over time with higher fractions of terrigenous organic matter being present in the most recent sediments this may be a result of increased input of terrigenous organic matter possibly due to sewage supply to the fjord over the last decades organic c and caco3 contents of the sediments do not appear to reflect a productivity signal calcium carbonate content is influenced by chemogenic calcite formation biogenic opal content appears to reflect a productivity signal but different degrees of dissolution may obscure its clear recognition

incorporation of satellite derived snow cover area in spatial snowmelt modeling for a large area determination of a gridded degree day factor spatial degree day factors ddfs are required for spatial snowmelt modeling over large areas by the degree day method we propose a method to obtain ddfs by incorporating snow disappearance dates sdds derived from 10 day composites of satellite pour l observation de la terre spot vegetation data into the degree day method this approach allowed determination of ddfs for each gridpoint so as to better reflect regional characteristics than use of spatially constant ddfs obtained from point measurements simulations at six observation sites successfully accounted for variations in snow water equivalent swe even at elevations different from the closest measurement site these results suggest that incorporating satellite derived sdds into the degree day method decreases spatial uncertainty compared with the use of spatially constant ddfs application of our method to japanese cold regions revealed that gridded ddfs were negatively correlated with accumulated positive degree days apdds and were high only when apdds were low these results imply that high ddfs resulted from the dominant contribution of solar radiation to snowmelt at low temperatures and that low ddfs resulted from a relatively high contribution of sensible heat flux at high temperatures the proposed method seems to adequately account for the main energetic components of snowmelt during the snow cover season over large areas

terrigenous input to a fjord in central norway records the environmental response to the north atlantic oscillation over the past 50 years during the last century both earth surface temperature and moisture transport towards high latitudes have increased rapidly the response of the sub arctic region to these changes in terms of weathering transport and delivery of terrigenous material towards the coastal and deep ocean is both complex and poorly understood sediments accumulating in fjords offer an excellent opportunity for studying such land ocean interactions and may provide ultra high resolution records of environmental response to short term climate variability as a basis for holocene climate change studies modern sources supply and distribution of particular sediment components in the trondheimsfjord have been investigated and imply lithogenic elements as a promising proxy for terrigenous input and river discharge to better understand the impact of atmospheric variability on central norwegian environment we examine instrumental time series and show that the dominant mode of the atmospheric circulation in the north atlantic region the north atlantic oscillation nao has a strong impact on river discharge temperature and precipitation in central norway in addition elemental composition analysis of a short sediment core reveals that from 1959 to 2010 winter precipitation and temperature changes are recorded by changes in the inorganic geochemical composition of trondheimsfjord sediments elemental ratios of al zr and k ni in the sediment core mc99 3 show a close relation to small scale high frequency climate variations and large scale changes in the northern hemisphere climate this implies that terrigenous input and related erosional processes in the fjord hinterland are highly sensitive to atmospheric circulation variability in the north atlantic region by comparing our results with nao records derived from ice accumulation rates of norwegian glaciers western greenland ice sheets and river discharge anomalies in the eurasian arctic we show that it is possible to reconstruct the nao from sedimentary archives in central norwegian fjords

the sources and deposition of organic matter in the late quaternary pigmy basin gulf of mexico abstract the concentration and carbon isotopic composition 13c of sedimentary organic carbon corg n c ratios and terrigenous and marine 13corg endmembers form a basis from which to address problems of late quaternary glacial interglacial climatic variability in a 208 7 m hydraulic piston core dsdp 619 from the pigmy basin in the northern gulf of mexico while interpretations of sedimentary 13corg time series records are often not unique paired analyses of 13corg and n c are consistent with the hypothesis that the corg in the pigmy basin is a climatically determined mixture of c3 photosynthetic terrigenous and marine organic matter confirming the earlier 13corg model of sackett 1964 a high resolution 1 4 2 9 ka sample 13corg record shows that sedimentary organic carbon in interglacial oxygen isotope sub stages 1 and 5a b are enriched in 13c average 1 values are 24 2 1 2 o and 22 9 0 7 o relative to pdb respectively while glacial isotope stage values 2 are relatively depleted 25 6 0 5 concentrations of terrigenous and marine sedimentary organic carbon are calculated for the first time using 13corg and corg measurements and empirically determined terrigenous and marine 13corg endmembers the net accumulation rate of terrigenous organic carbon is 4 3 2 6 times higher in isotope stages 2 4 than in sub stages 1 and 5a b recording higher erosion rates of terrigenous organic material in glacial times the concentration and net accumulation rates of marine and terrigenous corg suggest that the nutrient bearing plume of the mississippi river may have advanced and retreated across the pigmy basin as sea level fell and rose in response to glacial interglacial sea level change

a numerical model to simulate snow cover stratigraphy for operational avalanche forecasting laws of snow metamorphism have been introduced in a numerical model which simulates the evolution of temperature density and liquid water profiles of snow cover as a function of weather conditions to establish these laws the authors have summarized previous studies on temperature gradient and on wet snow metamorphism and they have also conducted metamorphism experiments on dry or wet fresh snow samples an original formalism was developed to allow a description of snow with parameters evolving continuously throughout time the introduction of laws of metamorphism has improved significantly the derivation of the settlement of internal layers and of snow covered albedo which depend on the simulated stratigraphy i e the type and size of snow grains of different layers of the snow cover the model was tested during a whole winter season without any re initialization comparison between the simulated characteristics of the snow cover and the observations made in the field are described in detail the model proved itself to be very efficient in simulating accurately the evolution of the snow cover stratigraphy throughout the whole winter season

re examining southern hemisphere westerly wind behavior insights from a late holocene precipitation reconstruction using new zealand fjord sediments abstract the behavior of the southern hemisphere westerly winds sww is inherently linked with climate variability understanding past sww climate feedbacks is key to predicting future climate change however we are limited by a lack of sww reconstructions particularly from the southwest pacific here we examine fjord sediments from fiordland new zealand 44 5 46 5 s to determine how the sww have fluctuated in position and strength in response to regional late holocene climate change and we compare our record to patagonia climate reconstructions in order to evaluate large scale sww behavior sww flow over the southern alps of new zealand drives orographic rainfall that is recorded within fjord sediments as changes in the relative contributions of terrestrial to marine organic matter which can be measured by bulk sediment 13 c and organic c n ratios using these proxies cores from three new zealand fjords show that precipitation decreased between 1400 1100 and 750 150 cal yr bp with short duration shifts toward drier conditions at 1900 and 900 cal yr bp precipitation increased 2100 1400 and 1100 700 cal yr bp with a short interval of wetter conditions around 400 cal yr bp these results indicate that westerly airflow over new zealand was stronger weaker during intervals of relatively warm cool climate our comparison of precipitation reconstructions from fiordland and patagonia shows dissimilarities in sww flow between regions while to date most mechanisms for changing the sww have invoked purely zonal shifts our results suggest that meridional changes in sww flow occurred in addition to zonal shifts in fiordland the meridional airflow associated with sam and or el nino like climate phenomena may be responsible for wet intervals while sam and or la nina like phenomena may promote dry conditions

geochemistry and mineralogy of the nw aegean sea surface sediments implications for river runoff and anthropogenic impact abstract surface sediments of the nw aegean sea were analyzed for clay mineral composition 94 samples organic c and carbonate content and major and minor elements 112 samples illite is the most abundant clay mineral followed by smectite chlorite and kaolinite clay minerals are preferentially deposited within the continental shelf and slope environment due to the prevailing cyclonic circulation and the formation of flocs in the rivers pro delta areas the spatial distribution of major lithogenic elements si al ti fe is substantially biased by the presence of relict sands located in the central eastern part of the thermaikos gulf continental shelf biogenic elements ca sr are noticeably pronounced on the northern flank of the north sporades islands organic c content and minor elements cu zn as and pb are enriched markedly over the thessaloniki bay and gulf suggesting substantial human impact deriving largely from untreated or partly treated domestic and industrial effluents the terrigenous component of the elements is preferentially contributed from the axios river zn and pb the aliakmon river cr co ni cu and as and to a lesser extent from the pinios river v co ni and cu a considerable part of the metals originates in ultra mafic and volcanic formations which are abundant in the rivers catchment basins carbonate content exhibits great variability with the highest values observed in biogenic sediments of the sporades basin in the latter area mn and fe oxides and hydroxides were found as coatings on calcite the coatings were enriched in cr co ni zn as mo and pb due to adsorption or ion exchange during early diagenesis the combined influence of the river systems the thessaloniki metropolis and the diverse sedimentological background generates great patchiness in the distribution of major and minor elements

late holocene sea surface temperature and precipitation variability in northern patagonia chile jacaf fjord 44 s abstract a high resolution multi proxy study including the elemental and isotopic composition of bulk organic matter land plant derived biomarkers and alkenone based sea surface temperature sst from a marine sedimentary record obtained from the jacaf fjord in northern chilean patagonia 44 20 s provided a detailed reconstruction of continental runoff precipitation and summer sst spanning the last 1750 yr we observed two different regimes of climate variability in our record a relatively dry warm period before 900 cal yr bp lower runoff and average sst 1 c warmer than present day and a wet cold period after 750 cal yr bp higher runoff and average sst 1 c colder than present day relatively colder ssts were found during 750 600 and 450 250 cal yr bp where the latter period roughly corresponds to the interval defined for the little ice age lia similar climatic swings have been observed previously in continental and marine archives of the last two millennia from central and southern chile suggesting a strong latitudinal sensitivity to changes in the southern westerly winds the main source of precipitation in southern chile and validating the regional nature of the lia our results reveal the importance of the chilean fjord system for recording climate changes of regional and global significance

recent distribution and accumulation of organic carbon on the continental margin west off spitsbergen the study compiles the controlling factors for organic matter sedimentation patterns from a suite of organogeochemical parameters in surface sediments off spitsbergen and direct seabed observations using a remotely operated vehicle rov in addition we assess its storage rates as well as the potential of carbon sinks on the northwestern margin of the barents sea with short sediment cores from a selected fjord environment storfjord while sedimentation in the fjords is mainly controlled by river meltwater discharge and coastal erosion by sea ice glaciers resulting in high supply of terrigenous organic matter atlantic water inflow and thus enhanced marine organic matter supply characterizes the environment on the outer shelf and slope local deviations from this pattern particularly on the shelf are due to erosion and out washing of fine grained material by bottom currents spots dominated by marine productivity close to the island have been found at the outer isfjord and west off prins karls forland as well as off the kongsfjord krossfjord area and probably reflect local upwelling of nutrient rich atlantic water derived water masses accumulation rates of marine organic carbon as well as reconstructed primary productivities decreased since the middle of the last century negative correlation of the isfjord temperature record with reconstructed productivities in the storfjord could be explained by a reduced annual duration of the marginal ice zone in the area due to global warming extremely high accumulation rates of marine organic carbon between 5 4 and 17 2 g m 2 yr 1 mark the storfjord area and probably high latitude fjord environments in general as a sink for carbon dioxide

twentieth century proxy records of temperature and soil organic matter input in the drammensfjord southern norway abstract the drammensfjord in southern norway is an enclosed anoxic basin with a laminated sedimentary record the fjord is a transition area between the marine and terrestrial environments and thus its sedimentary archive contains information on both environments in order to reconstruct recent environmental changes in southern norway two sediment cores covering the last 90 years were analyzed we used the branched versus isoprenoid tetraether bit index as an indicator of terrestrial organic mater input and compared it to the stable carbon isotopic composition of total organic carbon 13 c toc the 13 c toc and bit index show opposing trends with 13 c toc indicating an increase in terrestrial input while the bit index suggests a decrease towards the present this contradiction is probably due to the different sources reflected by 13 c toc vegetation soil and anthropogenic input and the bit index only soil organic matter input in addition an increase in the recycling of respired co 2 within the fjord s water column could have depleted the 13 c toc of the marine component towards more negative values thus seemingly indicating an increase in terrestrial input whilst the bit index could have been affected by a reduction of riverine input and or an increase in archaeal biomass production the tetraether index of lipids with 86 carbons tex 86 was determined as a proxy for past water surface temperatures while some of the signal could be coming from the chemocline our results suggest that tex 86 indicates surface upper 25 m temperatures moreover tex 86 temperature patterns seem to follow variations in the historical record of averaged spring to fall oslo air temperature relatively closely suggesting the signal is produced during this period therefore tex 86 temperature records of fjord sediment cores can potentially be a useful tool in reconstructing past variations of coastal climates

geochemistry of surface sediments from the fjords of northern chilean patagonia 44 47 s spatial variability and implications for paleoclimate reconstructions abstract the patagonian fjords have a clear potential to provide high resolution sedimentary and geochemical records of past climate and environmental change in the southern andes to improve our ability to interpret these proxy records we investigated the processes that control fjord sediment inorganic geochemistry through a geochemical mineralogical and sedimentological analysis of surface sediment samples from the fjords of northern chilean patagonia a simple terrestrial index based on measurements of salinity and fraction of terrestrial carbon was used to estimate the terrestrial input river discharge at each site our results demonstrate that under the cold climate conditions of patagonia chemical weathering is weak and the inorganic geochemical composition of the fjord sediments is primarily controlled by hydrodynamic mineralogical sorting i e the intensity of river discharge our results suggest that the distribution of fe ti and zr in surface sediments is controlled by their association with heavy and or coarse minerals whereas al is independent of hydrodynamic processes the elemental ratios fe al ti al and zr al are therefore well suited for estimating changes in the energy of terrestrial sediment supply into the fjords through time zr al is particularly sensitive in proximal environments while fe al is most useful in the outer fjords and on the continental margin in the most proximal environments however fe al is inversely related to hydrodynamic conditions caution should therefore be exercised when interpreting fe al ratios in terms of past river discharge the application of these proxies to long sediment cores from quitralco fjord and golfo elefantes validates our interpretations our results also emphasize the need to measure al based elemental ratios at high precision which can be achieved using simultaneous acquisition icp aes technology this study therefore constitutes a strong basis for the interpretation of sedimentary records from the chilean fjords

treeline and timberline dynamics on the northern and southern slopes of the retezat mountains romania during the late glacial and the holocene abstract to investigate treeline and timberline dynamics in the retezat mountains romanian carpathians late glacial and holocene sediment sequences from four lakes were studied the south and north slopes of the mountain range were compared using two lakes from the north flank lake brazi 1740 m a s l and lake gales 1990 m a s l and two from the south flank lake lia 1910 m a s l and lake bucura 2040 m a s l macrofossil and stomata analyses were performed to assess changes in the local vegetation supplemented by pollen charcoal and loss on ignition analyses our results show that treeline reached lake brazi on the northern side during the late glacial ca 14 000 cal yr bp and then lake gales between 11 000 and 10 800 cal yr bp during the early holocene the upper limit of closed forest the timberline reached and passed lake brazi and has stayed above it since but it has never reached lake gales at 1990 m a s l the expansion of larix decidua in the late glacialand early holocene around lake brazi is unique stomata and macrofossils of abies alba are also more abundant in the northern records on the southern flank treeline reached lake lia at around 12 000 cal yr bp and was either very close to or at the elevation of lake bucura between ca 8600 and 3000 cal yr bp timberline reached lake lia at ca 8000 cal yr bp some 3000 years after lake brazi only 170 m lower on the north slope local fire events delayed the advance of timberline around lake lia in the early holocene in a dry continental climate the surrounding forest was dominated by picea abies with individuals of pinus cembra and stands of p mugo until about 3000 cal yr bp when timberline retreated below the lake maximum elevation of timberline was attained between ca 8000 and 3000 cal yr bp after which it descended in response to climate cooling regional climate change appears to be the main driver of treeline dynamics but it was modified by local climatic differences due to slope aspect the first signs of human disturbance appeared ca 4200 cal yr bp when naturally open areas were used as alpine pastures human impact in the treeline ecotone mainly burning and grazing was intensified after ca 2600 cal yr bp contributing to the widening of the ecotone and the lowering of the timberline

high rates of organic carbon burial in fjord sediments globally fjords have been hypothesized to be hotspots of organic carbon burial a global compilation of organic carbon data and sedimentation rates shows that fjords sequester twice as much carbon as other ocean regions