9. Reconstruction of the Late Pleistocene and Holocene environmental evolution of the Laptev Sea continental margin inferred from high-resolution records of benthic and planktic foraminifers
11. Interannual variation of abundance and spatial distribution of phytoplankton in the Laptev Sea: a comparison of three autumnal investigations: 2008, 2009 and 2010 years
Ye. Polyakova, I. Kryukova, N. Man'ko
N. Alexeevsky, A. Chetverova, L. Kuksina
This proposal is based on results obtained from expeditions to the Lena delta by scientists from Arctic and Antarctic Research Institute (AARI), St. Petersburg State University (SPbSU), Moscow State University (MSU) and Alfred Wegener Institute (AWI), carrying out of the supportedby OSL in 2008-2011 and DFG grant in 2009. The main idea of the project is to determine how the channel branching of the Lena delta influences to the transformation of different kind of flows (water flow, flows of SPM, dissolved components and heat flow). The majority of water streams of the Lena's delta aren't studied in the hydrological and geochemical meaning. Researches of relationship between morphometric characteristics and water discharges are conducted for their subsequent usage in the solution of the return tasks (determination of water content for not studied deltoid water channels with the width of their channels, received by results of satellite data processing). Research on this proposal will be concentrated on a detailed study of structure of the Delta's channels network and different kind of flows in the Lena delta using of satellite images, field measurements and laboratory analysis. As a result of the study the GIS project of the Delta is planning to be created.
O. Anisimov, J. Strelchenko, V. Kokorev
The project objective is to quantify the impact of enhanced methane emission at the shelf of the East Siberian Arctic Seas (ESAS) on the global climate through analysis of available hydrographic, atmospheric and climatic data and mathematical modelling. Hydrographical data analysis will be performed in collaboration with the research team of Leibniz Institute of Marine Sciences at the University of Kiel. Together with the research team of AWI, Potsdam, we shall develop conceptual model of sub-sea permafrost dynamics, gas hydrate stability, and methane emission at the ESAS that accounts for different methane sources and is consistent with availableobservations. We shall develop a new comprehensive mathematical model of sub-aquatic permafrost dynamics that accounts for the effect of salt diffusion on thawing of bottom sediments and perform retrospective and predictive calculations forcing the model with paleoclimatological data (starting at 8 KY b.p.) and GCM-based climate projections for the 21st century. We shall use parameterized model of microbial methane production in the near bottom layer of organic sediments for calculating methane emissions under different bottom water temperature regimes. Ultimately, we shall estimate the global temperature rise associated with enhanced methane emissions at ESAS and evaluate the range of uncertainty.
N. Bubenshchikova, E. Brovina
In the modern Okhotsk Sea, the inflowing surface East Kamchatka Current and intermediate Deep Pacific Water (DPW) along south-west Kamchatka prevent expansion of the sea ice cover and contribute to intensity of marine productivity and oxygen minimum zone (OMZ). We plan to reconstruct variations of the East Kamchatka Current during the marine isotope stages (MIS) 1 and 5e basing on the surface temperature estimates from planktonic foraminiferal assemblages and theMg/Ca ratio of planktonic foraminifers. To investigate changes of the DPW inflow during the MIS 1 and 5e, we will provide reconstructions of the OMZ by benthic foraminiferal assemblages with the Mg/Ca temperatures on benthic foraminifers. We selected three sediment cores located on the Kamchatka slope in the main pathway of the North Pacific water inflow. We will extend our paleoreconstructions on core MD01-2415 studied in the framework of the grant OSL-2011 and focus on a composite record of cores LV28-43-3/ LV29-108-5. The study will be performed by using the equipments of P.P. Shirshov Institute of Oceanology in Moscow, IFM-GEOMAR in Kiel and the OSL in St.-Petersburg.
G. Cherkashov, E. Bazhenova, S. Kostygov, E. Novikhina
The proposed research will be focused on reconstructions of paleoenvironmental conditions and depositional processes in the Amerasian Basin of the Arctic Ocean during late Quaternary times. We will utilize marine sediment cores recovered at the Mendeleev Ridge and in the adjacent shelf- and deep-sea areas during the ARK-XXIII/3 Expedition of RV "Polarstern" in 2008 and the cruises of RV "Akademik Fedorov" in 2007 and 2008.We would like to 1) study the role of different transport agents in the sediment deposition with the help of the sedigraph grain-size analysis; 2) to determine the provenance of terrigenous material by means of counting and classification of ice-rafted debris under the microscope, and 3) to make paleoenvironmental reconstructions based on the foraminiferal analysis. To interpret our proxy records, we will use the stratigraphic framework that has been constrained for our cores based on the paleomagnetics, radiocarbon and amino acid racemization ages, as well as oxygen stable isotope composition. We plan to improve this age model using the new biostratigraphic data to be obtained from the foraminiferal analysis. To summarize, we would like to provide new records of late Quaternary paleoenvironmental changes in the Arctic Ocean with improved stratigraphy for the Mendeleev Ridge sediments.
S. Evgrafova, V. Kholodilova, E. Vorozhtsova
Arctic tundra and boreal forest soils have globally relevant functions that affect atmospheric chemistry and climate. However, the microbial communities as the drivers of carbon decomposition in Siberian permafrost-affected soils have been little studied so far. In this study we suppose to investigate the microbial community structure and activity of two Siberian regions: arctic (N 72°, E 126°) and sub-arctic (N 64°, E 100°) like representative areas of tundra and boreal forests. PLFA and PLEL analyses will be used to assess a biodiversity of the active part of soil microbial community in both regions. Basal respiration of soil microbial populationswill be analyzed for assessment of heterotrophic respiration rates. This study comprises a comparison of geographically distant soil microbial communities in order to answer the question: how do the structure and activity of specific microbial populations depending on C-content and C\N ratio as well as temperature, freeze/thaw cycle and moisture conditions. The data obtained will help for the better understanding of the carbon dynamics in permafrost under global climate change.
A. Krylov, P. Semenov, V. Dedyukhin
The Quaternary history of the Arctic shelf features multiple dramatic changes associated with glaciations and deglaciations of the Arctic periphery and sea level fluctuations. Considerable amount of organic matter delivered to Arctic shelves from the different sourcesand buried in sediments is serving as a potential material for in situ methane generation. Numerous oil and gas deposits discovered in Kara seas are important sources for methane leakage upwards along faults and weak zones in the sediments. Under certain PT conditions methane in sediments of the Kara Sea is able to form gas hydrates. Hydrocarbons including methane stored in sediments represent potentially important agent affecting the climate when the hydrocarbon gases release to the atmosphere due to permafrost destruction, dissociating hydrates and decomposition of sedimentary organic matter under the global warming. Methane might be an important driving force for global warming since it is a powerful greenhouse gas 25 times more potent than carbon dioxide. Emission of the methane from the sediments is potentially a strong climate feedback mechanism. The central objective of this project is to advance our understanding of the processes of gas release from the seafloor on the Kara Sea.
Due to hydrostatic imbalance and atmospheric circulation, water from the North Pacific flows through the Bering Strait, transits the upper levels of the Arctic Ocean, and penetrates to the North Atlantic. Pacific Summer Water (PSW) (flows through the Bering Strait in summer) is a main freshwater source in the Canadian Basin and influences thermohaline structure of the whole Arctic Ocean. Our previous study revealed a significant interannual variability of PSW characteristics such as area extent, volume and heat content. Based on the recent data obtained during International Polar Year we found the anomalous high extent of PSW in 2009. This anomaly is likely associated with a 2009 shift in the large-scale atmospheric circulation. Using annual reconstructed oceanographic data for a period from 1950 to 1989 and data obtained during numerous expeditions from 1991 to 2011 we are planning to investigate how atmospheric processes associated with changes in atmospheric climate modes (i.e. Arctic Oscillation, Pacific Decadal Oscillation and etc.) influence on circulation of PSW in the Arctic Ocean.
T. Matveeva, A. Portnov, E. Logvina
An establishment of subsea permafrost distribution in the Arctic shelf region as a whole (and the Kara Sea in particular) is one of the key problems for the climate changes understanding of the past and future. As most climate models predict a rapid climate change of the Arctic within the next few decades, the release of methane from marine permafrost and shallow marine sediments, is likely to increase. At present, it is still unclear whether methane anomalies in the Arctic shelf region as a whole (and the Kara Sea, in particular) are reflect natural variability in background emissions, or whether they really represent a new methane source (induced by the thawing of permafrost). The main goal of the proposed project is understanding of the current state of subsea permafrost within NE Kara Sea and the time scale of it's evolution in context of climate change of the Arctic. In particular, detailed mapping of permafrost distribution within NE Kara Sea is one of the targets ofthe proposed project. This will be done by comparison of new original geophysical data obtained during 59 cruise of Russian RV "Akademik Mstislav Keldysh" in the Kara Sea (17 September – 7 October 2011) with those available over the study area.
The project deals with foraminiferal distribution in surface sediments and marine sediment cores from different parts of the Laptev Sea aimed to extend reliability of paleoreconstructions of the Late Glacial to Holocene history of this region. Analysis of modern foraminifers will enlarge the existing scarce database of their distribution in the Laptev Sea in dependence to river runoff influence, water depth, bottom sediment composition and food supply (Tamanova, 1971; Bude, 1997; Lukina, 2001, 2004). This will support the high-resolution investigation of fossil assemblages of planktic and benthic foraminifers from six AMS14C-dated cores from the inner, middle, outer shelf and upper continental slope, that represent the transect from 21 to 270 m water depth. The core from the slope dates back to >15.4 cal.ka (extrapolated basal age 17.6 cal.ka) and contains the longest marine record in this area including the evidenceof past Atlantic-derived water inflows to the Laptev Sea continental margin. Fossil assemblages from the mid-outer shelf cores reflect periods of Holocene transgressive changes from impoverished nearshore environments to the present outer shelf settings. Cores from the inner shelf display late Holocene changes in estuarine shallow water circulation. This review is planned to be published and defended as a PhD Thesis.
The present proposal deals with high-resolution investigation of millennial-scale variability of paleoceanographic conditions in the western Bering Sea during the Late Pleistocene – Holocene. The results of this project will be the major contribution to the PhD Thesis of PI. Thecore SO201-2-85KL was retrieved from Shirshov Ridge, western Bering Sea, during the RV SONNE cruise 201 Leg 2 in 2009 in framework of the Russian-German KALMAR project. This core recovers the last ca. 170 kyr according to the stratigraphy provided by the Russian and German partners. This project is mainly aimed to complete the first high-resolution micropaleontological study in the poorly investigated subarctic western Bering Sea. Based on the continuous micropaleontological and sedimentological record in the core SO201-2-85KL, we intend to develop the detailed paleoenvironmental history of the region from the Late Pleistocene through the Holocene. The research will include available published results on the same core, comparison of benthic foraminiferal data with planktic foraminireral and diatom records, and independent geochemical proxies (e.g. oxygen and carbon isotope measurements), as well as interregional correlation of long- and short-term events in the western Bering Sea with those inthe North Pacific and Sea of Okhotsk in the context of regional and global climate changes.
Ye. Polyakova, I. Kryukova, N. Man'ko
The Laptev Sea polynya is a major area of sea-ice production at the Arctic Ocean, and it is one of the key elements of environmental system of the Laptev Sea, because of high level of biological activity in this regionduring the spring and early summer time. The main goals of our proposed investigations in the frame of current proposal are the study of species composition and abundances of microalga communities (diatoms, dinoflagellates, chrysophytes, chlorophytes) in the ice cores and the upper water column, using sea-ice core and phytoplankton samples obtained during TRANSDIFT-XIII expedition to the Laptev Sea polynya area in April, 2008. Sea-ice alga will be studied from three levels: bottom (10 cm), middle and surface layers, and phytoplankton will be studied from the water depth 1 m, 5 m, and 10 m. The following analysis will be applied in this study: (i) counting of total algal biomass and their species composition, (ii) detail investigations of diatoms and dinoflagellates (living forms and cysts), as the major component of the Arctic sea ice and phytoplankton bloom during the spring; (iii) in order to be useful as an indicator of the presence offormer sea ice conditions, a new chemical biomarker will be studied from the bottom sea-ice communities in combination with diatom records, as methodological basis. We suppose to reveal regional peculiarity in species composition and productivity of sea ice algal communities and ice-edge phytoplankton in the Laptev Sea polynya area during the spring, and relationship between these two types of Arctic marine coenosis.
I. Repina, D. Chechin, A. Aniferov
Weather forecasts in the Arctic are often unreliable, and the global climate models show a large uncertainty in scenarios. One of the reasons is that processes in the Arctic atmospheric boundary layer often are poorly implemented in these kinds of models. This is why mechanisms directly responsible for the exchange between the surface and the atmosphere need to be studied in great detail. The Arctic Atmospheric Boundary Layer structure depends mostly on the stability condition of the atmosphere, the surface processes and the orography of the site. The complex interactions between turbulence and radiation due to the presence of the Arctic clouds, haze and sea ice variation, make the parameterisation of the different ABL processes even more difficult.The project covers themes relevant for the Arctic atmospheric boundary layer such as: theory of the boundary layer with special emphasis on the stable boundary layer; turbulence; local climate processes; air-ice-sea interaction; data analysis; numerical modelling. Proposed research activities includes: collection and synthesis of meteorological data covering Arctic regions with different stratification; testing of different ABL models properties; design of new parameterization schemes for turbulent exchange in the surface layer, computation of ABL structure over different polynyas and leads.
A. Semushin, A. Pavlov, V. Yavlovskaya
Colored Dissolved Organic Matter (CDOM) of terrestrial origin plays a key role in the biogeochemistry and upper layer physics in the Arctic Ocean and of relevance for many interdisciplinary studies. Over the last decade, properties and distribution of CDOM were well documented in all Arctic shelf seas except for the White Sea, despite previous reports on highest loading of organic material transported by large rivers into the White Sea. The overall goal of the proposed study is to fill the gap in the knowledge on CDOM properties, distribution, and seasonal dynamics.. For that three comprehensive sampling programs throughout the year 2012 (May - October) will be carried out in the estuaries of two large rivers – Northern Dvina and Onega.Along with CDOM samples, salinity and temperature of the water will be measured. Properties of CDOM will be assessed with spectrophotometric technique using OSL laboratory facilities in St. Petersburg. Obtained results will contribute to a better understanding of the DOM state in the White Sea and the Arctic Ocean in light of the projected increase in freshwater run-off, and hence, DOM flux into the Arctic.
V. Shevchenko, D. Starodymova, V. Kashchenko
We plan to study the role of aeolian transport of chemical elements and compounds (including black carbon and pollutants) in the Arctic Ocean and surrounding land in the climate change. We would like to estimate changes in delivery and accumulation of different types of particulate matter. Multidisciplinary approach is necessary. Our work will be focused on samples from the Eurasian Arctic seas and their catchment areas, Central Arctic Ocean. We plan to study the composition of aerosols, snow, ice. We will compare our results with literature data from the other Arctic regions. This project could link Laptev Sea System, Polar Regions and Coasts in a ChangingEarth System, Land-Ocean Interactions in the Coastal Zone, Arctic Monitoring and Assessment Programme with active Russian-German cooperation.
E. Taldenkova, A. Stepanova, N. Chistyakova
The project deals with the reconstruction of postglacial environmental history of the eastern Laptev Sea continental margin in the context of regional changes and overregional climate variability based on high-resolution records of lithological characteristics, IRD, microfossils (benthic and planktic foraminifers, ostracods) and stable isotope composition of calcareous foraminifers from AMS14C-dated marine sediment cores PS2458 and PS51/118-3. It is a continuation of the running project OSL¬11-22 originally planned for 2 years, as both more than 8 m long cores are investigated continuously in 1 to 2 cm thick slices. The so far obtained results revealed important findings concerning such issues as: i) continuous eastward propagation of Atlantic-derived waters along the Laptev Sea continental slope since early deglacial times; ii) 13 cal. ka freshwater event in the Arctic reflected in core PS2458 by the simultaneous occurrence of the negative peak in d18O record of planktic foraminifers, scarcity of benthics, and extreme abundance of vivanite concretions indicative of anaerobic conditions at the sea floor probably due to water stratification, the situation that needs further investigation and explanation; iii) peaks in IRD input in the upper parts of the cores likely indicative of the late Holocene climate cooling, southward migration of the average seasonal drift ice limit and growing of ice caps in the western Laptev Sea.
The proposed project is aimed to recover information about past environmental and climatic changes of Holocene age from the sedimentary record of Lake El'gene-Kyuele, Lena River Lower, by means of lithostratigraphic (structure, texture, mineralogy) and geochemical (organic and inorganic indicators) methods. The study material is a part of the field material jointly collected with German colleagues during the expedition "Lena-2010" and will be analyzed in collaboration with them. This research will be going in frame of the applicant's education as per the Master's programme at the Faculty of Geology, St. Petersburg State University.