ALBERT

Description:    We present a high-resolution, multiproxy reconstruction of the depositional history of Lake Arreo, northern Spain, for the last 60 years. We conducted sedimentological, geochemical and diatom analyses in short cores and made a detailed comparison with regional instrumental climate data (1952–2007), limnological monitoring of the lake (1992–2008) and recent land use changes that affect the lake catchment. Chronology is based on “floating” discontinuous varve counts and 137 Cs and 14 C dates. Four periods were identified in the Lake Arreo recent history: (1) prior to 1963, varved facies intercalated with fine turbidite deposits, and diatom assemblages dominated by Cyclotella taxa indicate predominantly meromictic conditions, (2) from 1964 to 1978, permanent anoxia persisted in bottom waters, as shown by similar facies and diatom assemblages as before, though detrital layers were coarser, (3) from 1979 to 1994, sediment delivery to the lake increased and laminated, clastic facies were deposited, and (4) from 1995 to 2008, dominance of massive facies and an increase in Fragilaria tenera and Achnanthes minutissima reflect relatively lower lake levels, less frequent bottom anoxia with more frequent water column mixing, similar to modern conditions. The period 1952–1979 was a time of meromixis and varved facies deposition, and was characterized by higher rainfall and less intense agricultural pressure in the watershed. There were two short humid periods (1992–1993 and 1996–1998) when monitoring data show more anoxic weeks per year and relatively higher lake levels. Increased cultivation of small landholdings in 1963, and particularly after 1979, caused a large increase in sediment delivery to the lake. The inferred lake evolution is in agreement with monitoring data that suggest a transition from dominantly meromictic conditions prior to 1993–1994 to a predominantly monomictic pattern of circulation since then, particularly after 2000. The synergistic effects of intensive water extraction for irrigation and lower rainfall since 1979, and particularly since 1994, brought the long period of meromictic conditions in Lake Arreo to an end. Water balance and sediment delivery to the lake are dominant factors that control the limnological and mixing conditions in Lake Arreo and they must be considered in management and restoration plans. Content Type Journal Article Pages 1-17 DOI 10.1007/s10933-010-9492-7 Authors Juan Pablo Corella, Pyrenean Institute of Ecology (CSIC), Avda. Montañana 1005, 50080 Zaragoza, Spain Adel El Amrani, Departamento de Ecología, Universidad Autónoma de Madrid, C/Darwin, no. 2, 28049 Madrid, Spain Javier Sigró, Centre for Climate Change (C3), University Rovira i Virgili, Campus Catalunya 35, 43002 Tarragona, Spain Mario Morellón, Pyrenean Institute of Ecology (CSIC), Avda. Montañana 1005, 50080 Zaragoza, Spain Eugenio Rico, Departamento de Ecología, Universidad Autónoma de Madrid, C/Darwin, no. 2, 28049 Madrid, Spain Blas Lorenzo Valero-Garcés, Pyrenean Institute of Ecology (CSIC), Avda. Montañana 1005, 50080 Zaragoza, Spain Journal Journal of Paleolimnology Online ISSN 1573-0417 Print ISSN 0921-2728

Description:    Sediment cores collected from embayed lakes along the east-central coast of Lake Michigan are used to construct aeolian sand records of past coastal dune mobility, and to constrain former lake levels in the Lake Michigan basin. Time series analysis of sand cycles based on the weight-percent aeolian sand within lacustrine sediment, reveals statistically significant spectral peaks that coincide with established lake level cycles in Lake Michigan and the Gleissberg sunspot cycle of minima. Longer cycles of ~ 800 and ~ 2200 years were also identified that correspond to solar cycles. Shorter cycles between 80 and 220 years suggest a link between coastal dune mobility, climate, and lake levels in the Lake Michigan basin. Radiocarbon-dated sedimentary contacts of lacustrine sediment overlying wetland sediment record the Nipissing transgression in the Lake Michigan basin. Lake level rise closely mimics the predicted uplift of the North Bay outlet, with lake level rise slowing when outflow was transferred to the Port Huron/Sarnia outlet. The Nipissing highstand was reached after 5000 cal (4.4 ka) BP. Content Type Journal Article Pages 1-18 DOI 10.1007/s10933-010-9460-2 Authors Timothy G. Fisher, Department of Environmental Sciences, MS-604, University of Toledo, Toledo, OH 43606, USA Kelly A. Weyer, Department of Environmental Sciences, MS-604, University of Toledo, Toledo, OH 43606, USA Amber M. Boudreau, Department of Environmental Sciences, MS-604, University of Toledo, Toledo, OH 43606, USA James M. Martin-Hayden, Department of Environmental Sciences, MS-604, University of Toledo, Toledo, OH 43606, USA David E. Krantz, Department of Environmental Sciences, MS-604, University of Toledo, Toledo, OH 43606, USA Andy Breckenridge, Department of Geology, Mercyhurst College, 501 E. 38th St., Erie, PA 16546, USA Journal Journal of Paleolimnology Online ISSN 1573-0417 Print ISSN 0921-2728

Description:    Eutrophication from nutrient over-enrichment is a serious problem for the coastal zone and the estuarine environment globally. Australian estuaries are generally oligotrophic, but assessing whether they are becoming more eutrophic over time is inhibited by a lack of long-term monitoring data. The Richmond River, Australia, provided an ideal example of an estuary under anthropogenic pressure where the use of paleoecological techniques may potentially be used to reconstruct changes in nutrient status over time. Five cores were extracted from depositional areas in the Richmond River, and subjected to paleo-magnetic profiling and loss-on-ignition testing to ensure the core of greatest integrity was selected for further analytical work. Results from diatom and stable isotope analyses combined with 210 Pb and AMS 14 C dating show a strong indication that the total phosphorus levels in the Richmond River have fluctuated since 1940. Evidence also suggests that these fluctuations are most likely a function of climate. This study has successfully applied paleolimnological techniques to the estuarine environment to produce information that can be used by environmental managers to aid decision making in relation to nutrient control for the Richmond River. Further work using paleolimnological techniques should be aimed at the extraction of a core containing diatoms that pre-date European settlement and include analyses of specific lipids and fatty acid biomarkers. Content Type Journal Article Pages 1-15 DOI 10.1007/s10933-010-9457-x Authors Brendan Logan, School of Environmental Science and Management, Southern Cross University, PO Box 157, Lismore, NSW 2480, Australia Kathryn H. Taffs, School of Environmental Science and Management, Southern Cross University, PO Box 157, Lismore, NSW 2480, Australia Bradley D. Eyre, School of Environmental Science and Management, Southern Cross University, PO Box 157, Lismore, NSW 2480, Australia Atun Zawadski, ANSTO Institute for Environmental Research, New Illawarra Rd, PMB 1, Lucas Heights, NSW 2234, Australia Journal Journal of Paleolimnology Online ISSN 1573-0417 Print ISSN 0921-2728

Description:    To quantify the relationship between diatom species assemblages and the water chemistry of southeast Australian estuaries and coastal lakes, a new dataset of 81 modern diatom samples and water chemistry data was created. Three hundred and ninety-nine species from 53 genera were identified in 36 samples from 32 coastal water bodies in eastern Tasmania and 45 samples from 13 coastal water bodies in southern Victoria. Multivariate statistical analyses revealed that the sampling sites were primarily distributed along salinity and nutrient gradients, and that salinity, nitrate + nitrite, phosphate and turbidity explained independent portions of variance in the diatom data. Species salinity optima and tolerances were determined and a diatom-salinity inference model (WAinv r 2  = 0.72, r 2 jack = 0.58, RMSEP = 0.09 log ppt) was developed. This new information on diatom species’ salinity preferences provides a useful tool for quantitatively reconstructing salinity changes over time from diatom microfossils preserved in the sediments of a range of estuaries and coastal lakes in southeast Australia. This is valuable for studies investigating long-term human impacts and climate change in the region. Content Type Journal Article Pages 1-18 DOI 10.1007/s10933-010-9456-y Authors Krystyna M. Saunders, University of Bern Institute of Geography and Oeschger Centre for Climate Change Research Bern 3012 Switzerland Journal Journal of Paleolimnology Online ISSN 1573-0417 Print ISSN 0921-2728

Description:    I addressed the effects of taphonomic and early diagenetic processes on the isotope composition of cladoceran remains, using both experimental and field approaches. An experiment was designed to mimic the conditions encountered by cladoceran remains when they settle through the water column and are buried in the sediment. Cladoceran exoskeletons were incubated for 4 months in oxic or anoxic water, and in sediment. Changes in their carbon (C) and nitrogen (N) content and isotope compositions were measured. Most changes in isotope composition of exoskeletons took place when they settled through the water column. Once buried in the sediment, however, the δ 13 C and δ 15 N values of cladoceran exoskeletons did not undergo further change. Taphonomic processes resulted in an increase in δ 13 C and δ 15 N of the cladoceran remains and this was related to microbial degradation, which selectively removed isotopically light C and N compounds from the remains. For δ 13 C, changes were minimal (〈1‰) and occured within the first 3 months. Taphonomic effects on δ 15 N were larger, from +2 to +5‰, and occurred within the first 2–3 weeks. These effects depended on incubation conditions and were greater in anoxic waters than under oxic conditions. Monthly changes in the isotope composition of sedimenting cladoceran exoskeletons were also recorded in the field using sediment traps, and were compared to the isotope composition of the living cladoceran community. The isotope composition of sedimenting remains displayed values consistent with those that might be expected, considering the effects of taphonomic processes observed in the experiment. Because C and N in cladoceran exoskeletons might involve a different isotope routing, the δ 15 N value of the remains provides an annual record of the value in the parent community, with a 1-month delay, while δ 13 C of remains essentially reflects that of the parent community during the period of lake thermal stratification. These findings provide insights into paleolimnological interpretation of isotopic changes in cladoceran remains from sediment cores. Content Type Journal Article Pages 1-11 DOI 10.1007/s10933-011-9532-y Authors Marie-Elodie Perga, National Institute for Agronomical Research (INRA), Alpine Centre for Research on Lake Ecosystems and Food Webs (CARRTEL), 75 Avenue de Corzent, BP 511, 74203 Thonon les Bains Cedex, France Journal Journal of Paleolimnology Online ISSN 1573-0417 Print ISSN 0921-2728

Description: M. Kernan, R. W. Batttarbee and B. R. Moss (eds): Climate change impacts on freshwater ecosystems Content Type Journal Article Pages 1-3 DOI 10.1007/s10933-011-9531-z Authors Christian Kamenik, Oeschger Centre for Climate Change Research, Institute of Geography, University of Bern, Erlachstrasse 9a, Trakt 3, 3012 Bern, Switzerland Journal Journal of Paleolimnology Online ISSN 1573-0417 Print ISSN 0921-2728

Description:    Sedimentation rates over the last 100 years within two lagoons on the southeast coast of Australia, Lake Illawarra and St Georges Basin, have been quantified to determine the effects of catchment land use change and native vegetation clearance on infill rates, and spatial variations in the rate at which the estuaries have filled. Both catchments have similar lake and catchment area but have experience different degrees of modification due to land clearing for agriculture practices, urbanisation and industrialisation. Results indicate that in the heavily modified catchment of Lake Illawarra sedimentation rates close to fluvial deltas can be in excess of 16 mm/year, and between 2 and 4 mm/year in the adjacent central basin. This is approximately an order of magnitude greater than the pre-European rates. In contrast, at St Georges Basin, where the catchment has experienced much less modification, sedimentation rates in the central basin appear to have remained close to those prior to European settlement. However, sedimentation rates in the urbanized margin of St Georges Basin are relatively high (up to 4.4 mm/year). This rapid modern sedimentation in the margin of the estuarine embayments has been detected in several other estuaries in the region. However the degree of sedimentation within the bay-head deltas, and more significantly in the central basin appears proportional to the degree clearance of native vegetation (forest) in the catchment, urban expansion and development of heavy industry in the respective catchment areas. Content Type Journal Article Pages 1-17 DOI 10.1007/s10933-011-9507-z Authors Craig R. Sloss, The Discipline of Biogeoscience, Queensland University of Technology, GPO Box 2434, Brisbane, QLD 4001, Australia Brian G. Jones, School of Earth and Environmental Sciences, University of Wollongong, Wollongong, NSW 2522, Australia Brendan P. Brooke, Geoscience Australia, GPO Box 1666, Canberra, ACT 2601, Australia Henk Heijnis, Australian Nuclear Science and Technology Organisation, Menai, NSW Australia Colin V. Murray-Wallace, School of Earth and Environmental Sciences, University of Wollongong, Wollongong, NSW 2522, Australia Journal Journal of Paleolimnology Online ISSN 1573-0417 Print ISSN 0921-2728

Description:    Glacial Lake Agassiz, the largest of the North American glacial lakes, discharged through several different outlets during its history, although the timing and location of discharge remain controversial. However, one discharge event is well established based on extensive onshore observations: drainage through the Nipigon Lake area into the Superior basin about 10,700 years ago, following retreat of ice of the Marquette advance from the basin. High-resolution, single-channel seismic-reflection data collected with a small airgun were acquired to test the hypothesis that the Post-Marquette drainage event left diagnostic stratigraphic and geomorphic signatures beneath Lake Superior. The unique bathymetry of northwestern Lake Superior, where water depth plunges off Nipigon and Black Bays, makes this location ideal for the characterization of the post-Marquette depositional and erosional features. According to our hypothesis, the initial, sudden discharge of high-velocity water would have eroded channels through the bays. The steep and sudden drop-off into the Superior basin would have caused the flow to slow and drop much of the sediment it was carrying. Our results confirm the existence of both erosional features and depositional sediment packages related to Lake Agassiz discharge at this time. The erosional features include deeply incised bedrock channels in the bays. The depositional features comprise subaqueous fans that are thickest in the deep water areas adjacent to the outlets and thin lakeward and laterally away from the channels. The seismic character of the basal units of the fans, proximal to the channels, is chaotic and only very weakly stratified, suggesting that these deposits represent coarse sediment laid down during the initial, high-energy stages of the flood. These sediments are overlain by a stratified package which is interpreted as the fine grained sediment associated with the later, low-energy stages of the flood. The combination of channels and subaqueous fans is inferred to be diagnostic of high-energy Lake Agassiz discharge into the Superior basin, and they serve as analogs for hypothesized discharge at other times. Content Type Journal Article Pages 1-13 DOI 10.1007/s10933-011-9503-3 Authors Jessica L. Gary, Large Lakes Observatory and Department of Geological Sciences, University of Minnesota Duluth, Duluth, MN USA Steven M. Colman, Large Lakes Observatory and Department of Geological Sciences, University of Minnesota Duluth, Duluth, MN USA Nigel J. Wattrus, Large Lakes Observatory and Department of Geological Sciences, University of Minnesota Duluth, Duluth, MN USA C. F. M. Lewis, Geological Survey of Canada—Atlantic, Natural Resources Canada, Dartmouth, NS Canada Journal Journal of Paleolimnology Online ISSN 1573-0417 Print ISSN 0921-2728

Description:    Monthly limnological monitoring in Lake Sanabria (Spain) since 1986 provided a unique opportunity to test relationships among climate, hydrology and lake dynamics and how they are recorded in the lake sediments. Four datasets were employed: (1) meteorological (monthly maximum and minimum air temperature and total precipitation), (2) limnological (Secchi disk, water temperature, conductivity, pH, dissolved oxygen, nitrate, silicon, total and reactive phosphorus, and total chlorophylls and chlorophyll a ), (3) hydrological (Tera River water input and output), and (4) XRF core scanner measurements carried out in short cores. Linear models between the different dataset variables allowed us to characterize the climate signal transmission from one to the other and cross-correlation analyses permitted us to identify the different response times (if any) between them. Principal Component Analyses (PCA) of the limnological and geochemical datasets allowed us to identify the main processes that link lake dynamics, primarily nutrient supply and organic productivity, with some sedimentological processes, e.g. organic matter and phosphorus accumulation. Sediment chronology was established by gamma spectrometry ( 210 Pb). Water input to Lake Sanabria is controlled mostly by the Tera River input and is linked directly to precipitation. Response of the Lake Sanabria water budget to climate oscillations is immediate, as the strongest correlation between these two datasets occurs with no lag time. PCA of the limnological dataset indicated that most of the variance is related to nutrient input, and comparison with the Tera River water discharge shows that nutrient input was controlled mainly by oscillations in the hydrological balance. The lag time between the hydrological and limnological datasets is 1 month. The PCA of the XRF core scanner dataset showed that the principal process that controls the chemical composition of the Lake Sanabria sediments is related to sediment and nutrient delivery from the Tera River and organic productivity. Comparison of the nutrient input reconstructed using the limnological dataset and the XRF core scanner data indicated that the sediments act as a low-pass filter, smoothing the climate signal. It was, however, possible to establish the link between these datasets, and obtain a quantitative reconstruction of precipitation for the 1959–2005 AD period that captures the regional variability. This quantitative precipitation reconstruction suggests it is possible to obtain accurate climate reconstructions using non-laminated sediments. Content Type Journal Article Pages 1-16 DOI 10.1007/s10933-011-9509-x Authors S. Giralt, Institute of Earth Sciences Jaume Almera (ICTJA-CSIC), Lluís Solé i Sabarís s/n, 08028 Barcelona, Spain M. T. Rico-Herrero, Pyrenean Institute of Ecology (IPE-CSIC), Av. Montañana 1005, 50059 Zaragoza, Spain J. C. Vega, Laboratory of Limnology of the Lago de Sanabria Natural Park, Eras 1, 49300 Puebla de Sanabria, Zamora Spain B. L. Valero-Garcés, Pyrenean Institute of Ecology (IPE-CSIC), Av. Montañana 1005, 50059 Zaragoza, Spain Journal Journal of Paleolimnology Online ISSN 1573-0417 Print ISSN 0921-2728

Description:    During the middle and late Holocene, the Iberian Peninsula underwent large climatic and hydrologic changes, but the temporal resolution and regional distribution of available palaeoenvironmental records is still insufficient for a comprehensive assessment of the regional variability. The high sedimentation rate in karstic, meromictic Montcortès Lake (Catalan pre-Pyrenees) allows for a detailed reconstruction of the regional palaeoecology over the last 5,340 years using diatom analysis, aquatic pollen, sedimentological data, and historic documentary records. Results show marked fluctuations in diatom species assemblage composition, mainly between dominant Cyclotella taxa and small Fragilariales. We suggest that the conspicuous alternation between Cyclotella comta and C. cyclopuncta reflects changes in trophic state, while the succession of centric and pennate species most likely reflects changes in the hydrology of the lake. The diatom assemblages were used to identify six main phases: (1) high productivity and likely lower lake levels before 2350 BC, (2) lower lake levels and a strong arid phase between 2350 and 1850 BC, (3) lake level increase between 1850 and 850 BC, (4) relatively high lake level with fluctuating conditions during the Iberian and Roman Epochs (650 BC–350 AD), (5) lower lake levels, unfavourable conditions for diatom preservation, eutrophication and erosion triggered by increased human activities in the watershed during the Medieval Climate Anomaly (900–1300 AD), and (6) relatively higher lake levels during the LIA (1380–1850 AD) and afterwards. The combined study of diatoms, algae and pollen provides a detailed reconstruction of past climate, which refines understanding of regional environmental variability and interactions between climate and socio-economic conditions in the Pyrenees. Content Type Journal Article Pages 1-17 DOI 10.1007/s10933-011-9524-y Authors Paolo Scussolini, Faculty of Biology, Department of Ecology, Universitat de Barcelona, Barcelona, Spain Teresa Vegas-Vilarrúbia, Faculty of Biology, Department of Ecology, Universitat de Barcelona, Barcelona, Spain Valentí Rull, Institut Botànic de Barcelona (CSIC-ICUB), Barcelona, Spain Juan Pablo Corella, Instituto Pirenaico de Ecología (CSIC-IPE), Zaragoza, Spain Blas Valero-Garcés, Instituto Pirenaico de Ecología (CSIC-IPE), Zaragoza, Spain Joan Gomà, Faculty of Biology, Department of Ecology, Universitat de Barcelona, Barcelona, Spain Journal Journal of Paleolimnology Online ISSN 1573-0417 Print ISSN 0921-2728