Journal articles on the topic 'Lake core'
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1
Oviatt, Charles G., Robert S. Thompson, Darrell S. Kaufman, Jordon Bright, and Richard M. Forester. "Reinterpretation of the Burmester Core, Bonneville Basin, Utah." Quaternary Research 52, no. 2 (September 1999): 180–84. http://dx.doi.org/10.1006/qres.1999.2058.
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Initial interpretation of the sediments from the Burmester core (Eardley et al. (1973). Geological Society of America Bulletin 84, 211–216) indicated that 17 deep-lake cycles, separated by shallow-lake and soil-forming intervals, occurred in the Bonneville basin during the Brunhes Chron (the last 780 × 103 yr). Our re-examination of the core, along with new sedimentological, geochronological, and paleontological data, indicate that only four deep-lake cycles occurred during this period, apparently correlative with marine oxygen-isotope stages 2, 6, 12, and 16. This interpretation suggests that large lakes formed in the Bonneville basin only during the most extensive of the Northern Hemisphere glaciations.
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Cvetkoska, A., E. Jovanovska, A. Francke, S. Tofilovska, H. Vogel, Z. Levkov, T. H. Donders, B. Wagner, and F. Wagner-Cremer. "Ecosystem regimes and responses in a coupled ancient lake system from MIS 5b to present: the diatom record of lakes Ohrid and Prespa." Biogeosciences Discussions 12, no. 17 (September 11, 2015): 15051–86. http://dx.doi.org/10.5194/bgd-12-15051-2015.
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Abstract. In order to understand the panarchy and interactions since the last interglacial period in the oldest, most diverse and hydrologically connected European lake system, we assess changes in the diatom record and selected geochemistry data from Lake Ohrid's "DEEP site" core and compare it with the diatom and multi-proxy data from Lake Prespa core Co1215. Driven by climate forcing, tephra impact and/or human influence, the lakes experienced two adaptive cycles during the last 92 ka: "interglacial and interstadial-regime" and "glacial-regime". The patterns of regime shifts appear synchronous in both lakes, while differences occur in the inferred amplitudes of the variations. The deeper Lake Ohrid shifted between ultraoligo- and oligotrophic regimes in contrast to the more shallow Lake Prespa, which shifts from (oligo-) mesotrophic to eutrophic conditions. In response to external forcing, Lake Ohrid exhibits a high capacity to buffer disturbances, whereas Lake Prespa is much more resilient and "recovers" in relatively short time. This decoupling of the response is evident during the MIS 5/4 and 2/1 transitions, when Lake Ohrid displays prolonged and gradual changes. The lakes' specific differences in the response and feedback mechanisms and their different physical and chemical properties, probably confine a direct influence of Lake Prespa's shallow/eutrophic regimes over the productivity regimes of Lake Ohrid. Regime shifts of Lake Ohrid due to the hydrological connectivity with Lake Prespa are not evident in the data presented here. Moreover, complete ecological collapse did not happened in both lakes for the period presented in the study.
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Cvetkoska, Aleksandra, Elena Jovanovska, Alexander Francke, Slavica Tofilovska, Hendrik Vogel, Zlatko Levkov, Timme H. Donders, Bernd Wagner, and Friederike Wagner-Cremer. "Ecosystem regimes and responses in a coupled ancient lake system from MIS 5b to present: the diatom record of lakes Ohrid and Prespa." Biogeosciences 13, no. 10 (May 31, 2016): 3147–62. http://dx.doi.org/10.5194/bg-13-3147-2016.
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Abstract. We reconstruct the aquatic ecosystem interactions since the last interglacial period in the oldest, most diverse, hydrologically connected European lake system, by using palaeolimnological diatom and selected geochemistry data from Lake Ohrid “DEEP site” core and equivalent data from Lake Prespa core, Co1215. Driven by climate forcing, the lakes experienced two adaptive cycles during the last 92 ka: "interglacial and interstadial" and "glacial" cycle. The short-term ecosystems reorganizations, e.g. regime shifts within these cycles substantially differ between the lakes, as evident from the inferred amplitudes of variation. The deeper Lake Ohrid shifted between ultra oligo- and oligotrophic regimes in contrast to the much shallower Lake Prespa, which shifted from a deeper, (oligo-) mesotrophic to a shallower, eutrophic lake and vice versa. Due to the high level of ecosystem stability (e.g. trophic state, lake level), Lake Ohrid appears relatively resistant to external forcing, such as climate and environmental change. Recovering in a relatively short time from major climate change, Lake Prespa is a resilient ecosystem. At the DEEP site, the decoupling between the lakes' response to climate change is marked in the prolonged and gradual changes during the MIS 5/4 and 2/1 transitions. These response differences and the lakes' different physical and chemical properties may limit the influence of Lake Prespa on Lake Ohrid. Regime shifts of Lake Ohrid due to potential hydrological change in Lake Prespa are not evident in the data presented here. Moreover, a complete collapse of the ecosystems functionality and loss of their diatom communities did not happen in either lake for the period presented in the study.
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Brooks, Gregory R., and Barbara E. Medioli. "Deposits and Cutoff Ages of Horseshoe and Marion Oxbow Lakes, Red River, Manitoba*." Géographie physique et Quaternaire 57, no. 2-3 (September 22, 2005): 151–58. http://dx.doi.org/10.7202/011310ar.
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Abstract Horseshoe Lake and the Marion Lake scar, along the Red River, southern Manitoba, were cored to investigate the timing of the meander cutoffs and the sedimentology of the channel in-fill deposits. The Horseshoe Lake core, 10.75 m long, consists of 9.73 m of silt-rich deposits inferred to be lacustrine from 0 to 4 m deep, transitional from 4 to 5 m deep and alluvial below 5 m deep. Four wood and charcoal specimens sampled from the core yielded radiocarbon ages of 310 ± 40, 1730 ± 50, 2040 ± 50 and 2240 ± 50 BP. The Marion Lake core, 16.77 m long, consists of 14.73 m of silt-rich deposits inferred to be lacustrine from 0 to 5 m deep and alluvial below 8.5 m deep; the transition is indistinct and falls between 5 to 8.5 m deep. Four wood samples from the fluvial deposits yielded radiocarbon ages of 1600 ± 40, 1700 ± 40, 1660 ± 40 and 1620 ± 40 BP. The cutoffs that led to the formation of Horseshoe and Marion lakes are interpreted to have occurred at ~1990 and ~1520 cal BP or shortly thereafter, respectively. The silt-rich, alluvial-lacustrine deposits in the lakes lack structural and textural characteristics that can be readily recognized in core to distinguish the depositional environments. The absence of coarse sediments at the base of the fluvial units at both sites implies that minor to negligible amounts of sand were transported along the thalwegs of the channels prior to the meanders being cutoff. The dominance of silt within the oxbow deposits reflects sediment supply as the geomorphic setting of the river is within an extensive glaciolacustrine clay plain.
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Russell, James M., Satria Bijaksana, Hendrik Vogel, Martin Melles, Jens Kallmeyer, Daniel Ariztegui, Sean Crowe, et al. "The Towuti Drilling Project: paleoenvironments, biological evolution, and geomicrobiology of a tropical Pacific lake." Scientific Drilling 21 (July 27, 2016): 29–40. http://dx.doi.org/10.5194/sd-21-29-2016.
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Abstract. The Towuti Drilling Project (TDP) is an international research program, whose goal is to understand long-term environmental and climatic change in the tropical western Pacific, the impacts of geological and environmental changes on the biological evolution of aquatic taxa, and the geomicrobiology and biogeochemistry of metal-rich, ultramafic-hosted lake sediments through the scientific drilling of Lake Towuti, southern Sulawesi, Indonesia. Lake Towuti is a large tectonic lake at the downstream end of the Malili lake system, a chain of five highly biodiverse lakes that are among the oldest lakes in Southeast Asia. In 2015 we carried out a scientific drilling program on Lake Towuti using the International Continental Scientific Drilling Program (ICDP) Deep Lakes Drilling System (DLDS). We recovered a total of ∼ 1018 m of core from 11 drilling sites with water depths ranging from 156 to 200 m. Recovery averaged 91.7 %, and the maximum drilling depth was 175 m below the lake floor, penetrating the entire sedimentary infill of the basin. Initial data from core and borehole logging indicate that these cores record the evolution of a highly dynamic tectonic and limnological system, with clear indications of orbital-scale climate variability during the mid- to late Pleistocene.
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Brugam, Richard B., Eric C. Grimm, and Nancy M. Eyster-Smith. "Holocene Environmental Changes in Lily Lake, Minnesota Inferred from Fossil Diatom and Pollen Assemblages." Quaternary Research 30, no. 1 (July 1988): 53–66. http://dx.doi.org/10.1016/0033-5894(88)90087-7.
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A postglacial core was taken from Lily Lake, a soft-water lake, located on carbonate-poor till in eastern Minnesota. Pollen analysis allowed the reconstruction of watershed vegetation change. Diatom assemblages from the core were compared with 255 surface sediment assemblages from Minnesota, Maine, Labrador, and the Canadian arctic. Late-glacial assemblages were similar to Canadian arctic lakes. During the mid-postglacial period of warmer and drier climate, fossil diatom assemblages at Lily Lake were similar to those in the surface sediment of modern eutrophic hardwater lakes in Central Minnesota. The shift to hardwater diatom assemblages coincided with a shift to prairie species in fossil pollen assemblages at about 8000 yr B.P. At about 3400 year B.P. the fossil diatom assemblage that characterized presettlement times was established.
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Kennie, Patricia, Jim Bogen, and Hans Olsen. "Estimating long term sediment yields from sediment core analysis." Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation 42, no. 1 (January 1, 2010): 115–26. http://dx.doi.org/10.2478/v10060-008-0070-x.
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Estimating long term sediment yields from sediment core analysis Sediment cores from lakes and reservoirs can be used to estimate sediment yields. In proglacial lakes, the bed sediment typically accumulates as varves, reflecting changes in seasonal and annual sedimentation. This report compares the results from two different methods of measuring suspended sediment transport in a Norwegian glacial river and lake. Sediment yields obtained from a study of sediment cores in the proglacial lake Nigardsvatn along with measurements of the delta topset were compared with a 25-year record of sediment transport based on automatic water sampling and water discharge measurements at a monitoring station at the inflowing river. During the period from 1980 to 2005, analyses of sediment cores taken from the lake bed along with measurements and grain size distribution analysis of the delta indicated that a volume of 175,670 to 202,697 m3 was deposited in the lake Nigardsvatn and corresponding river delta. The year 1980 was selected as a convenient starting point because a large-magnitude flood with a 100-year recurrence interval occurred at the end of 1979, leaving an easily recognizable sediment layer and accurate reference point. Sediment cores were taken at a total of 24 locations throughout the lake and 25 locations in the delta. The densities of the sediment cores were found to vary between 1.3 and 1.5 g/cm3 during the period examined in this study, giving a total suspended sediment load of between 175,670 and 202,697 tons. The measurements carried out at the sediment station in the glacier melt-water river gave a value of 294,800 tons during the same period. A final value of 211,100 tons is calculated from the monitoring station results after deduction of the sediment fraction which passes through the lake without being deposited. This gives a discrepancy between the two methods of 8,403 to 35,430 tons (4-20%). This can be partially attributed to the difficulties of measuring the water discharge in the unstable glacier meltwater river. In conclusion, sediment cores may be used to extrapolate or correct measurements from sediment monitoring stations over longer periods but caution should be made when considering single years.
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Fujisaki-Manome, Ayumi, Greg E. Mann, Eric J. Anderson, Philip Y. Chu, Lindsay E. Fitzpatrick, Stanley G. Benjamin, Eric P. James, Tatiana G. Smirnova, Curtis R. Alexander, and David M. Wright. "Improvements to Lake-Effect Snow Forecasts Using a One-Way Air–Lake Model Coupling Approach." Journal of Hydrometeorology 21, no. 12 (December 2020): 2813–28. http://dx.doi.org/10.1175/jhm-d-20-0079.1.
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AbstractLake-effect convective snowstorms frequently produce high-impact, hazardous winter weather conditions downwind of the North American Great Lakes. During lake-effect snow events, the lake surfaces can cool rapidly, and in some cases, notable development of ice cover occurs. Such rapid changes in the lake-surface conditions are not accounted for in existing operational weather forecast models, such as the National Oceanic and Atmospheric Administration’s (NOAA) High-Resolution Rapid Refresh (HRRR) model, resulting in reduced performance of lake-effect snow forecasts. As a milestone to future implementations in the Great Lakes Operational Forecast System (GLOFS) and HRRR, this study examines the one-way linkage between the hydrodynamic-ice model [the Finite-Volume Community Ocean Model coupled with the unstructured grid version of the Los Alamos Sea Ice Model (FVCOM-CICE), the physical core model of GLOFS] and the atmospheric model [the Weather Research and Forecasting (WRF) Model, the physical core model of HRRR]. The realistic representation of lake-surface cooling and ice development or its fractional coverage during three lake-effect snow events was achieved by feeding the FVCOM-CICE simulated lake-surface conditions to WRF (using a regional configuration of HRRR), resulting in the improved simulation of the turbulent heat fluxes over the lakes and resulting snow water equivalent in the downwind areas. This study shows that the one-way coupling is a practical approach that is well suited to the operational environment, as it requires little to no increase in computational resources yet can result in improved forecasts of regional weather and lake conditions.
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Morris, J. R., and W. Kwain. "Sediment pH in Profundal Core Samples from the Turkey Lakes (Algoma, Ontario)." Canadian Journal of Fisheries and Aquatic Sciences 45, S1 (December 19, 1988): s155—s158. http://dx.doi.org/10.1139/f88-280.
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Vertical pH profiles were recorded in sediment cores from four of the Turkey Lakes in the Algoma region of northern Ontario. In the three upper lakes of the chain, median down-core pH, which should be correlated with historic lake water pH, was below the median down-core pH for other lakes in northeastern Ontario. The Turkey lakes had probably been relatively acidic, therefore, since pre-industrial times. Down-core pH tended to be lower in upstream lakes. While a pH minimum was typically observed at the sediment–water interface, the surficial sediments were not acidified relative to down-core sediments.
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Vyse, Stuart A., Ulrike Herzschuh, Gregor Pfalz, Lyudmila A. Pestryakova, Bernhard Diekmann, Norbert Nowaczyk, and Boris K. Biskaborn. "Sediment and carbon accumulation in a glacial lake in Chukotka (Arctic Siberia) during the Late Pleistocene and Holocene: combining hydroacoustic profiling and down-core analyses." Biogeosciences 18, no. 16 (August 24, 2021): 4791–816. http://dx.doi.org/10.5194/bg-18-4791-2021.
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Abstract. Lakes act as important sinks for inorganic and organic sediment components. However, investigations of sedimentary carbon budgets within glacial lakes are currently absent from Arctic Siberia. The aim of this paper is to provide the first reconstruction of accumulation rates, sediment and carbon budgets from a lacustrine sediment core from Lake Rauchuagytgyn, Chukotka (Arctic Siberia). We combined multiple sediment biogeochemical and sedimentological parameters from a radiocarbon-dated 6.5 m sediment core with lake basin hydroacoustic data to derive sediment stratigraphy, sediment volumes and infill budgets. Our results distinguished three principal sediment and carbon accumulation regimes that could be identified across all measured environmental proxies including early Marine Isotope Stage 2 (MIS2) (ca. 29–23.4 ka cal BP), mid-MIS2–early MIS1 (ca. 23.4–11.69 ka cal BP) and the Holocene (ca. 11.69–present). Estimated organic carbon accumulation rates (OCARs) were higher within Holocene sediments (average 3.53 g OC m−2 a−1) than Pleistocene sediments (average 1.08 g OC m−2 a−1) and are similar to those calculated for boreal lakes from Quebec and Finland and Lake Baikal but significantly lower than Siberian thermokarst lakes and Alberta glacial lakes. Using a bootstrapping approach, we estimated the total organic carbon pool to be 0.26 ± 0.02 Mt and a total sediment pool of 25.7 ± 1.71 Mt within a hydroacoustically derived sediment volume of ca. 32 990 557 m3. The total organic carbon pool is substantially smaller than Alaskan yedoma, thermokarst lake sediments and Alberta glacial lakes but shares similarities with Finnish boreal lakes. Temporal variability in sediment and carbon accumulation dynamics at Lake Rauchuagytgyn is controlled predominantly by palaeoclimate variation that regulates lake ice-cover dynamics and catchment glacial, fluvial and permafrost processes through time. These processes, in turn, affect catchment and within-lake primary productivity as well as catchment soil development. Spatial differences compared to other lake systems at a trans-regional scale likely relate to the high-latitude, mountainous location of Lake Rauchuagytgyn.
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Maslennikova, Anna V., Valerii N. Udachin, Vladimir V. Deryagin, and Mikhail V. Shtenberg. "Reconstruction of Turgoyak lake (the Southern Urals) ecosystem changes in holocene." LITOSFERA, no. 6 (December 28, 2018): 914–27. http://dx.doi.org/10.24930/1681-9004-2018-18-6-914-927.
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Object. Multi-proxy analysis of 265 cm long sediments core of Lake Turgoyak, one of the deepest lakes of the Southern Urals, is presented. Materials and methods. The lake ecosystem changes was reconstructed based on diatom, radiocarbon dating and geochemical analysis. Statistical treatment of the surface sediments composition and hydrochemistry data of 56 lakes from Southern and Middle Urals lakes database allowed to obtain geochemical indexes for reconstruction of water parameters: index of organic matter content (ОМ = LOI550ºС/(Al2O3 + TiO2 + Na2O + K2O)) and index of salinity (ММ = LOI950ºC/LOI550ºС). Results. Radiocarbon dating shows that sedimentation in Lake Turgoyak was began more than 12 cal kyr BP ago. Each of six lithological units of sediments core is characterized by its own geochemical features and associated with global (11.8, 11.2, 8.2 cal kyr BP) and regional (12, 10.3 cal kyr BP) climate events of the Northern Hemisphere. Four main stages of Lake ecosystem development were identified: 1) the beginning of lake sedimentation (>12.1 cal kyr BP); 2) the stage of a subsaline shallow-water lake (12.1–11.2 cal kyr BP); 3) the stage of a freshwater lake with increased water-level (11.2–8.0 cal kyr BP); 4) the stage of water organic matter increase (<8.0 cal kyr BP). Conclusions. High content of mesohalobic diatoms and salinity module values showed significant increase of lake water salinity as response to Early Holocene climate warming (11.8–11.2 cal kyr BP). Pantle-Buck’s Saprobity Index and OM values pointed to the lake water organic matter increase due to the next climate warming since 9–8 cal kyr BP. Thus, Lake Turgoyak water parameters were reapeatedly changed during the Holocene. However the response of lake ecosystem was different in different periods of its development.
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Peramaki, Liisa, and Michael Stone. "Fluxes of As, Cu, Hg, Pb in lake sediments in the Coppermine River basin, Canada." Hydrology Research 38, no. 2 (April 1, 2007): 177–85. http://dx.doi.org/10.2166/nh.2007.006.
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Many watersheds in northern Canada are experiencing increasing pressures from resource extraction, development and the long-range transport of atmospheric pollutants. This study examines sediment accumulation and the spatial and temporal distribution of trace metals in bottom sediment of down gradient lakes in the headwaters of the Coppermine River basin, Canada. Sediment cores were collected from Lac de Gras, Desteffany Lake, Point Lake and Daring Lake using a plastic lined K–B single-gravity corer. Each core was dated using 210Pb and concentrations of trace metals (As, Cu, Hg, Pb) were determined in core sections. Sedimentation rates ranged from 101 g m−2 yr−1 at Desteffany Lake to 156 g m−2 yr−1 at Daring Lake and are comparable to other northern lakes. Concentrations of As and Cu were significantly higher at Lac de Gras. Metal loading data and enrichment ratios show that concentrations of Pb and Hg are elevated compared to historic background levels. Metal enrichment is from anthropogenic activities and atmospheric inputs. Lake sediment represents a good indicator of state for the Coppermine basin and documents historic trends of metal deposition. However, the indicator has low sensitivity to change and coarse temporal resolution due to low sedimentation rates in northern environments.
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Mohammadi, Ali, Razyeh Lak, Georg Schwamborn, Amaneh Kaveh Firouz, Attila Çiner, and Javad Darvishi Khatouni. "Depositional environments and salt-thickness variations in Urmia Lake (NW Iran): Insight from sediment-core studies." Journal of Sedimentary Research 91, no. 3 (March 31, 2021): 296–316. http://dx.doi.org/10.2110/jsr.2020.078.
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ABSTRACT Urmia Lake is a large-scale hypersaline lake that experienced a drastic water-level fall due to natural and anthropogenic forces during the last two decades. Construction of a causeway in the central part of the lake after 1989 has divided the lake into northern and southern parts and caused an extreme change of the lake hydrochemical system. Precipitation of evaporite minerals as crust on the lake floor was caused by the combination of lake level fall and increasing water salinity. However, some parameters controlling rates of salt deposition and dissolution and temporal and spatial variation in salt thickness in Lake Urmia are poorly understood. This study reviews 90 sediment cores from various parts of the lake to put forward a better understanding of the salt depositional system and salt thickness variations in the basin for the last 40 years (1977–2017). Our results indicate that the sedimentary system of Urmia Lake changed rapidly during the last two decades from a permanent hypersaline lake with predominantly fast terrigenous–biochemical sedimentation to a seasonally changing playa sedimentary environment with predominance of evaporite minerals. These changes are responsible for rapid salt deposition that generated a salt-crust with a maximum thickness of 2.95 m overlying Holocene terrigenous sediments. The salt-crust thickness and the water depth have a positive correlation for water depth greater than 1 meter, which means that salt-crust thickness increases where water depth increases. While the thickness of shallow deposits are affected by fresh-water dissolution. In addition, the average salt precipitation rate in the northern and the southern parts of the lake is 466 and 266 times higher, respectively, than the average (0.3 mm/y) sedimentation rate before the lake shrinkage. Similar to other large hypersaline lakes such as the Great Salt Lake (USA) and the Aral Sea (Central Asia), the manmade intervention at Urmia Lake (damming of the catchment, extension of agricultural fields, and causeway construction in the middle part of the lake) threatens its further hydrologic existence.
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Yansa, Catherine H., Albert E. Fulton, Randall J. Schaetzl, Jennifer M. Kettle, and Alan F. Arbogast. "Interpreting basal sediments and plant fossils in kettle lakes: insights from Silver Lake, Michigan, USA." Canadian Journal of Earth Sciences 57, no. 2 (February 2020): 292–305. http://dx.doi.org/10.1139/cjes-2018-0338.
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We report on pollen, plant macrofossils, and associated lithostratigraphy of a sediment core extracted from the base of Silver Lake, a kettle lake in northern Lower Michigan, USA, which reveal a complex deglacial scenario for ice block melting and lake formation, and subsequent plant colonization. Complementary multivariate statistical and squared chord distance analyses of the pollen data support these interpretations. The basal radiocarbon age from the core (17 540 cal years BP) is rejected as being anomalously old, based on biostratigraphic anomalies in the core and the date’s incongruity with respect to the accepted regional deglaciation chronology. We reason that this erroneous age estimate resulted from the redeposition of middle-Wisconsin-age fossils by the ice sheet, mixed with the remains of plants that existed as the kettle lake formed at ca. 10 940 cal years BP by ice block ablation. Thereafter, the kettle lake became a reliable repository of Holocene-age fossils, documenting a mature boreal forest that existed until 10 640 cal years BP, followed by a pine-dominated mixed forest, an early variant of the mixed conifer–hardwood forest that persists to the present day. Our study demonstrates that researchers investigating kettle lakes, a common depositional archive for plant fossils in deglaciated landscapes, should exercise caution in interpreting the basal (Late Pleistocene/early Holocene-age) part of lake sediment cores.
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Roberts, D., A. McMinn, and D. Zwartz. "An initial palaeosalinity history of Jaw Lake, Bunger Hills based on a diatom–salinity transfer function applied to sediment cores." Antarctic Science 12, no. 2 (June 2000): 172–76. http://dx.doi.org/10.1017/s0954102000000225.
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Two sediment cores taken from Jaw lake (Bunger Hills, East Antarctica) were analysed for diatom composition and abundance. A diatom-salinity transfer function developed for the nearby Vestfold Hills was used to determine palaeosalinity reconstructions from the assemblages preserved in each of the cores. There is a large step-wise decrease in salinity in the second core from at least c. 4000 to c. 2000 uncorrected 14C yr BP. The salinity record from the first core starts at c. 3000 uncorrected 14C yr BP and is comparable with the salinity of the second core between c. 3000 and c. 2000 uncorrected 14C yr BP. Sudden lake water dilution in both cores at c. 1900 uncorrected 14C yr BP is followed by brief increases in lake water salinity between c. 1900 and c. 500 uncorrected 14C yr BP, after which gradual dilution to present occurs. This analysis of the local environmental history of this saline lake reveals a mid–late Holocene evolution of the lake basin similar to that documented from earlier marine and freshwater lacustrine sediments in the Bunger Hills. The high coherence of the independent sediment records suggests a robust general palaeosalinity reconstruction of the lake is achieved in addition to providing evidence for the fidelity of single sediment cores as useful and adequate representation of the palaeolimnological histories of Antarctic lakes.
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Curt Stager, Jay, Kenneth Alton, Christopher H. Martin, David T. King, Lucille W. Petruny, Brendan Wiltse, and Daniel A. Livingstone. "On the Age and Origin of Lake Ejagham, Cameroon, and Its Endemic Fishes." Quaternary Research 89, no. 1 (July 20, 2017): 21–32. http://dx.doi.org/10.1017/qua.2017.37.
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AbstractLake Ejagham is a small, shallow lake in Cameroon, West Africa, which supports five endemic species of cichlid fishes in two distinct lineages. Genetic evidence suggests a relatively young age for the species flocks, but supporting geologic evidence has thus far been unavailable. Here we present diatom, geochemical, mineralogical, and radiocarbon data from two sediment cores that provide new insights into the age and origin of Lake Ejagham and its endemic fishes. Radiocarbon ages at the base of the longer core indicate that the lake formed approximately 9 ka ago, and the diatom record of the shorter core suggests that hydroclimate variability during the last 3 millennia was similar to that of other lakes in Cameroon and Ghana. These findings establish a maximum age of ca. 9 cal ka BP for the lake and its endemic species and suggest that repeated cichlid speciation in two distinct lineages occurred rapidly within the lake. Local geology and West African paleoclimate records argue against a volcanic, chemical, or climatic origin for Lake Ejagham. Although not conclusive, the morphometry of the lake and possible signs of impact-induced effects on quartz grains are instead more suggestive of a bolide impact.
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Foit, Franklin F., and Peter J. Mehringer. "Holocene tephra stratigraphy in four lakes in southeastern Oregon and northwestern Nevada, USA." Quaternary Research 85, no. 2 (March 2016): 218–26. http://dx.doi.org/10.1016/j.yqres.2015.12.008.
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To better understand the regional tephra stratigraphy and chronology of northern Nevada and southern Oregon, tephras in archived cores, taken as part of the Steens Mountain Prehistory Project from four lakes, Diamond Pond, Fish and Wildhorse lakes in southeastern Oregon and Blue Lake in northwestern Nevada, were reexamined using more advanced electron microprobe analytical technology. The best preserved and most complete core from Fish Lake along with Wildhorse Lake hosted two tephras from Mt. Mazama (Llao Rock and the Climactic Mazama), a mid-Holocene basaltic tephra from Diamond Craters, Oregon, two Medicine Lake tephras and an unexpected late Holocene Chaos Crags (Mt. Lassen volcanic center) tephra which was also found in the other lakes. Blue Lake was the only lake that hosted a Devils Hill tephra from the Three Sisters volcano in west central Oregon. Another tephra from the Three Sisters Volcano previously reported in sediments of Twin Lakes in NE Oregon, has now been confirmed as Rock Mesa tephra. The Chaos Crags, Devils Hill and Rock Mesa tephras are important late Holocene stratigraphic markers for central and eastern Oregon and northwestern Nevada.
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Harasimiuk, Andrzej, Bogumił Wicik, and Tomasz Grabowski. "The lake deposits in Płock Basin (case studies of Lakes Rakutowskie and Żłoby)." Limnological Review 10, no. 1 (January 1, 2010): 23–28. http://dx.doi.org/10.2478/v10194-011-0003-7.
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The lake deposits in Płock Basin (case studies of Lakes Rakutowskie and Żłoby)Reconstruction of development of Lakes Rakutowskie and Żłoby in the late Pleistocene and Holocene was the aim of this research. Analysis of content of calcium carbonate, organic matter and C14 datings (7 samples) were done for two cores of sediments of 750 cm long. An average rate of accumulation was counted. Sediments of Lake Rakutowskie show homogeneity along the core which indicates similarity of sedimentation conditions. Sediments of Lake Żłoby were diversified and show variety related to cyclic changes. A common feature is a thick layer of fine sand without carbonate deposited during the older dryas, shown in both cores. The difference in sediment features of both lakes (which have similar depths) indicates that the Lake Żłoby is the more dynamic, filtering element, preceding Lake Rakutowskie in system of water catchment.
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Oliva, F., A. E. Viau, J. Bjornson, N. Desrochers, and M. A. Bonneau. "A 1300 year reconstruction of paleofloods using oxbow lake sediments in temperate southwestern Quebec, Canada." Canadian Journal of Earth Sciences 53, no. 4 (April 2016): 378–86. http://dx.doi.org/10.1139/cjes-2015-0191.
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The study of paleofloods provides important information on past flood frequency and intensity for regions where there is a paucity of records; it therefore extends our knowledge of flood occurrence beyond the historical record. Many paleoflood reconstructions come from the arid dry climate of southwestern USA and from Europe, with few studies being conducted in temperate climates of North America. This study uses sediment cores from oxbow lakes to reconstruct past flood events in a temperate region. Cores extracted from two oxbow lakes along the Désert River in southwestern Quebec, Canada, were analyzed for magnetic susceptibility, loss on ignition, and grain size and were radiocarbon dated (14C). Using a combination of magnetic susceptibility variations, along with changes in grain size and organic material content, five floods were identified within the 220 cm core (1300 years) from the North oxbow lake, and six floods in the 118 cm core (600 years) from the South oxbow lake. This study provides evidence to support the use of oxbow lakes in temperate regions as a proxy of past floods, thus helping us understand hydroclimatic changes at regional scales. Data that span a longer period of time and in different environments are key to increase flood modelling accuracy to improve mitigation strategies under a changing climate.
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Leng, M. J., I. Baneschi, G. Zanchetta, C. N. Jex, B. Wagner, and H. Vogel. "Late Quaternary palaeoenvironmental reconstruction from Lakes Ohrid and Prespa (Macedonia/Albania border) using stable isotopes." Biogeosciences Discussions 7, no. 3 (May 21, 2010): 3815–53. http://dx.doi.org/10.5194/bgd-7-3815-2010.
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Abstract. Here we present stable isotope data from three sediment records from lakes that lie along the Macedonian-Albanian border (Lake Prespa: 1 core, and Lake Ohrid: 2 cores). The records only overlap for the last 40 kyr, although the longest record contains the MIS 5/6 transition (Lake Ohrid). The sedimentary characteristics of both lakes differ significantly between the glacial and interglacial phases. At the end of MIS 6 Lake Ohrid's water level was low (high δ18Ocalcite) and, although productivity was increasing (high calcite content), the carbon supply was mainly from inorganic catchment rock sources (high δ13Ccarb). During the last interglacial, calcite and TOC production and preservation increased, progressively lower δ18Ocalcite suggest increase in humidity and lake levels till around 115 ka. During ca. 80 ka to 11 ka the lake records suggest cold conditions as indicated by negligible calcite precipitation and low organic matter content. In Lake Ohrid δ13Corg are complacent, in contrast Lake Prespa shows consistently higher δ13Corg suggesting a low oxidation of 13C-depleted organic matter in agreement with a general deterioration of climate conditions during the glacial. From 15 ka to the onset of the Holocene, calcite and TOC begin to increase, suggesting lake levels were probably low (high δ18Ocalcite). In the Holocene (11 ka to present) enhanced productivity is manifested by high calcite and organic matter content. All three cores show an early Holocene characterised by low δ18Ocalcite, apart from the very early Holocene phase in Prespa where the lowest δ18Ocalcite occurs at ca. 7.5 ka, suggesting a phase of higher lake level only in (the more sensitive) Lake Prespa. From 6 ka δ18Ocalcite suggest progressive aridification, in agreement with many other records in the Mediterranean, although the uppermost sediments in one core records low δ18Ocalcite which we interpret as a result of human activity. Overall, the isotope data present here confirm that these two big lakes have captured the large scale, low frequency palaeoclimate variation that is seen in Mediterranean lakes, although in detail there is much palaeoclimate information that could be gained, especially small scale, high frequency differences between this region and the Mediterranean.
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Leng, M. J., I. Baneschi, G. Zanchetta, C. N. Jex, B. Wagner, and H. Vogel. "Late Quaternary palaeoenvironmental reconstruction from Lakes Ohrid and Prespa (Macedonia/Albania border) using stable isotopes." Biogeosciences 7, no. 10 (October 13, 2010): 3109–22. http://dx.doi.org/10.5194/bg-7-3109-2010.
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Abstract. Here we present stable isotope data from three sediment records from lakes that lie along the Macedonian-Albanian border (Lake Prespa: 1 core, and Lake Ohrid: 2 cores). The records only overlap for the last 40 kyr, although the longest record contains the MIS 5/6 transition (Lake Ohrid). The sedimentary characteristics of both lakes differ significantly between the glacial and interglacial phases. At the end of MIS 6 Lake Ohrid's water level was low (high δ18Ocalcite) and, although productivity was increasing (high calcite content), the carbon supply was mainly from inorganic catchment rock sources (high δ13Ccarb). During the last interglacial, calcite and TOC production and preservation increased, progressively lower δ18Ocalcite suggest increase in humidity and lake levels until around 115 ka. During ca. 80 ka to 11 ka the lake records suggest cold conditions as indicated by negligible calcite precipitation and low organic matter content. In Lake Ohrid, δ13Corg are complacent; in contrast, Lake Prespa shows consistently higher δ13Corg suggesting a low oxidation of 13C-depleted organic matter in agreement with a general deterioration of climate conditions during the glacial. From 15 ka to the onset of the Holocene, calcite and TOC begin to increase, suggesting lake levels were probably low (high δ18Ocalcite). In the Holocene (11 ka to present) enhanced productivity is manifested by high calcite and organic matter content. All three cores show an early Holocene characterised by low δ18Ocalcite, apart from the very early Holocene phase in Prespa where the lowest δ18Ocalcite occurs at ca. 7.5 ka, suggesting a phase of higher lake level only in (the more sensitive) Lake Prespa. From 6 ka, δ18Ocalcite suggest progressive aridification, in agreement with many other records in the Mediterranean, although the uppermost sediments in one core records low δ18Ocalcite which we interpret as a result of human activity. Overall, the isotope data present here confirm that these two big lakes have captured the large scale, low frequency palaeoclimate variation that is seen in Mediterranean lakes, although in detail there is much palaeoclimate information that could be gained, especially small scale, high frequency differences between this region and the Mediterranean.
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Moran, K., M. Paulson, M. Lengkeek, P. Jeffery, and A. Frazer. "Deep Water Scientific Drilling in Lake Malawi, Africa." Marine Technology Society Journal 40, no. 1 (March 1, 2006): 29–35. http://dx.doi.org/10.4031/002533206787353637.
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A new deep water drilling system was developed and applied to recover deeply buried sediments for scientific analyses in one of the deep rift valley lakes of Africa—Malawi. This approach overcame the difficulty of maintaining position over a drill site in a remotely located, large, deep lake. Environmental conditions in Lake Malawi are similar to deep water marine settings and, as such, a marine approach was adopted for the Lake Malawi Drilling Project (LMDP). In February and March 2005, the modified pontoon, Viphya, successfully completed a scientific drilling expedition in Lake Malawi. This expedition recovered core at depths greater than 380 m below lake-floor in water depths as great as 600 m. The major refit of Viphya included installation of a moonpool, bridge, crew accommodations, mess, washroom, power system, dynamic positioning, and a drilling system. These major modifications required early pontoon surveys and naval architectural analyses and design work prior to their commencement. The expedition also used modified scientific coring tools with a marine geotechnical drilling rig for the first time, resulting in excellent core recovery and quality.
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Filippova, K. G., E. A. Konstantinov, O. K. Borisova, N. V. Kuzmenkova, A. L. Zakharov, and A. A. Medvedev. "Lake Chukhlomskoe in the Late Pleistocene and Holocene (Kostroma region, Russia)." Limnology and Freshwater Biology, no. 4 (2022): 1417–20. http://dx.doi.org/10.31951/2658-3518-2022-a-4-1417.
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Abstract. The article discusses the first results of geomorphological and paleolimnological study of Lake Chukhlomskoe (Kostroma region). We analyzed the topography of the lake bottom using new bathymetric data from 2021 fieldwork. The structure of the lake basin slopes was studied using hand drilling. Analytical characteristics of the bottom sediments core (grain size distribution, loss on ignition, magnetic susceptibility, AMS-dating and palynological data) are presented. The distribution of organic matter, carbonates and particle size by depth allow us to correlate the bottom sediments of Lake Chukhlomskoe with the sediments of other well-studied large lakes (Belaya Struga, Galichskoe and Seliger).
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Kholia, Neha, Bahadur Singh Kotlia, David Porinchu, Kamini Bisht, Anupam Sharma, and Poonam Jalal. "Sedimentological and Grain Size Characteristics of Two Lake Cores from Himachal Pradesh, India." Journal of Climate Change 7, no. 4 (December 18, 2021): 35–51. http://dx.doi.org/10.3233/jcc210024.
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Two lake cores from Khajjiar (length 746 cm) and Rewalsar lakes (length 647 cm) in Himachal Pradesh (India) were retrieved to understand the sedimentological characteristics and variation in grain size distribution. Both the lake cores are Upper Holocene in age. The Rewalsar lake sediments are composed predominantly of silt with small amounts of clay, whereas the Khajjiar sediments contain sand, silt and clay and both cores have high carbonaceous matter. The standard deviation ranges from 0.88 ϕ to 2.56 ϕ for Khajjiar lake and from 0.957 ϕ to 2.264 ϕ for Rewalsar lake, indicating poorly to very poorly sorted core sediments. The values of the Kurtosis vary between 0.678 ϕ and 1.205 ϕ for Khajjiar lake and from 0.8 ϕ to 1.2.4 ϕ for Rewalsar lake, viewing platykurtic to leptokurtic nature. Further, the skewness value ranges from -0.097 ϕ to 0.240 ϕ for Khajjiar lake and 0.079 ϕ to 0.25 ϕ for Rewalsar lake revealing fine to symmetrical skewness model. The bivariate plots by using the grain-size parameters were also interpreted. The Total Organic Carbon (TOC) is higher in the Khajjiar lake sediments (0.9 to 31.2%; av. 10.6%), compared to that in the Rewalsar lake sediments (1.0 to 9.0; av. 2.6%). The sedimentological characteristics indicate that the energy conditions were linked to the climatic conditions prevailing in the area. In general, the Khajjiar lake core is composed of relatively coarser sediments and more affected by arid conditions while the fine fraction of the Rewalsar shows the consequence of lower energy conditions. The Khajjiar lake shows the transition from fluctuating conditions (zone 1) to humid (zone 2) to arid (zone 3), while the Rewalsar shows the change from fluctuating (zone 1) to humid conditions (zones 2 and 3). The similarity between zone 1 and 2 of both the lake profiles shows that both lakes have experienced similar climatic conditions during the deposition, revealing domination of fluctuating and arid conditions.
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Sigareva, L. E., N. A. Timofeeva, and V. V. Zakonnov. "Plant Pigments in Bottom Sediment Cores as Indicators of the Trophic State in Large Shallow Lakes Vozhe and Lacha (Russia)." Inland Water Biology 15, no. 3 (June 2022): 271–79. http://dx.doi.org/10.1134/s1995082922030130.
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Abstract The first data on the content of plant pigments is presented for the cores of bottom sediments sampled in large shallow lakes Vozhe and Lacha located in the upper reaches of the Onega River. In the 1-m core of olive silts, the total concentration of chlorophyll a and pheopigments varied within 35–236 (94.2 ± 3.3) in Lake Vozhe and 58–118 (83.8 ± 1.3) μg/g dry sediment in Lake Lacha. The degree of chlorophyll destruction in the cores from Lake Lacha (98.7 ± 0.2%) was higher than in Lake Vozhe (85.2 ± 0.7%). Considering the average long-term sedimentation rate of 0.2 and 0.4 mm/year in Lakes Vozhe and Lacha, respectively, the annual vertical flux of chlorophyll a and pheopigments is 4.0 and 6.2 mg/(m2 · year) for the last 2500 years, respectively. Nowadays, the average annual rate of pigment accumulation is almost the same in the lakes (5.6 and 5.3 mg/(m2 · year)). Over the period under consideration until now, different patterns of long-term dynamics of pigment accumulation in the studied lakes have been revealed; in particular, there is a positive trend in Lake Vozhe and a negative trend in Lake Lacha.
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Wood, Warren W., Stephen Stokes, and Julie Rich. "Implications of Water Supply for Indigenous Americans during Holocene Aridity Phases on the Southern High Plains, USA." Quaternary Research 58, no. 2 (September 2002): 139–48. http://dx.doi.org/10.1006/qres.2002.2355.
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AbstractSprings in the 40 to 50 large lake basins (>15 km2) on the southern portion of the Southern High Plains (SHP) were active during periods of aridity in the Holocene when there may have been human habitation of the area. Eolian erosion of the lake floors and lunette accretion occurred as groundwater levels declined in response to decreased groundwater recharge. The declining lake floor associated with eolian erosion allowed groundwater evaporative discharge to continue, thus maintaining a groundwater gradient toward the lake. This hydrologic condition was favorable for a relatively continuous spring discharge to the lake, independent of the elevation of the lake floor. To evaluate the postulated dynamic equilibrium critical to this conclusion, 17 optically stimulated ages were determined from a 17.7-m deep core of a lunette adjacent to Double Lakes, Texas (33°13′15″N, 101°54′08″W). The core yielded sediment accumulation dates of 11,500±1100, 6500±700, and 4900±500 yr B.P., corresponding broadly with periods of aridity known from other evidence. Based on analysis of this lunette, it is concluded that springs in Double Lakes basin probably existed throughout the Holocene with discharges similar to those observed historically. We assumed that similar dynamic equilibrium existed in the other large lake basins in the SHP and that these springs could have provided a continuous source of water for indigenous peoples during periods of prolonged aridity. The dynamic equilibrium that is proposed in this study is applicable not only to other arid and semiarid geographic areas with wind-erodible material but also over different geologic times.
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Laug, Andreas, Torsten Haberzettl, Andre Pannes, Anja Schwarz, Falko Turner, Junbo Wang, Stefan Engels, et al. "Holocene paleoenvironmental change inferred from two sediment cores collected in the Tibetan lake Taro Co." Journal of Paleolimnology 66, no. 3 (July 18, 2021): 171–86. http://dx.doi.org/10.1007/s10933-021-00198-6.
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AbstractThe Tibetan Plateau, also known as the “Water Tower of Asia” because of its function as a water storage and supply region, responds dramatically to modern climate changes. Paleoecological shifts inferred from lake sediment archives provide essential insights into past climate changes, and the processes that drove those shifts. This is especially true for studies of lakes in endorheic basins on the Tibetan Plateau, where lake level is regulated predominantly by Monsoon intensity. Such water bodies provide excellent opportunities to reconstruct past changes in humidity. Most paleolimnological investigations of lakes on the Tibetan Plateau, however, have involved the study of a single sediment core, making it difficult to discern between changes caused by local events and those caused by lake-wide or regional processes. Here we present results from a paleolimnological study of Lake Taro Co, a currently closed-basin lake in Central Tibet. We compared a sediment record from the central part of the lake to a record from the near-shore area, and present results of sedimentological and bioindicator (chironomid, diatom, pollen) analyses from both records. Results show three periods of lake-wide ecosystem change (> ca. 5250, 5250–2250 and < since about 2250 cal year BP), which reflect a continuous drying trend throughout the Middle and Late Holocene. In addition to this lake-wide trend, we identified two local events in the sediment core from the southeastern, nearshore site. These include (1) a hiatus between 12,400 and 5400 cal year BP and (2) an 1800-year period of distinct paleoenvironmental conditions (5400–3600 cal year BP). We hypothesize that both events were caused by relocation of a river in the southeast sector of the lake’s catchment. We propose that the first relocation caused an erosion event that removed sediment, thereby producing the hiatus. During the following 1800 years, the core site may have been located on the river delta, before another river relocation at 3600 cal year BP established the modern prodelta situation. Our study demonstrates the value of using multiple sediment cores from a lake, to better identify processes that control widespread versus local events.
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Dufour, Elise, William P. Patterson, Tomas O. Höök, and Edward S. Rutherford. "Early life history of Lake Michigan alewives (Alosa pseudoharengus) inferred from intra-otolith stable isotope ratios." Canadian Journal of Fisheries and Aquatic Sciences 62, no. 10 (October 1, 2005): 2362–70. http://dx.doi.org/10.1139/f05-147.
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We apply a robotic micromilling technique to the sampling of young-of-the-year (YOY) and 1+ otoliths from alewives (Alosa pseudoharengus) captured in different habitat types of Lake Michigan during 20012003. δ18O values of otolith cores of YOY alewives from Muskegon Lake (a sheltered, drowned river mouth lake connected to Lake Michigan), Muskegon Channel (which connects Muskegon Lake to Lake Michigan), and Lake Michigan proper are compared with δ18O values of ambient water from different potential early life habitats. Otolith core δ18O values used in conjunction with δ13C values serve as good discriminators of nursery areas. The majority of YOY alewives captured in Muskegon Lake emerge and grow in this habitat, whereas the majority of YOY alewives captured in Lake Michigan emerge and grow in Lake Michigan. In addition, early-life movements of alewives between the two lakes are documented but limited. Even if drowned river mouth lakes are more favorable for alewife growth and survival, their contribution to the Lake Michigan population could be limited because all of the 1+ alewives were individuals that spent their early life in Lake Michigan. The application of high-resolution isotope analysis of small otoliths of forage fish for fish population dynamics studies appears promising.
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Díaz, Karen A., Liseth Pérez, Alexander Correa-Metrio, Juan Felipe Franco-Gaviria, Paula Echeverría, Jason Curtis, and Mark Brenner. "Holocene environmental history of tropical, mid-altitude Lake Ocotalito, México, inferred from ostracodes and non-biological indicators." Holocene 27, no. 9 (January 18, 2017): 1308–17. http://dx.doi.org/10.1177/0959683616687384.
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This paleolimnological study used ostracodes assemblages, element concentrations, organic and inorganic carbon content, organic C:N ratios, and stable isotope values in valves of the ostracodes Cytheridella ilosvayi as paleoindicators and is the first such investigation from a mid-elevation site in southern México. We provide a ~7600-year (9540–1970 BP) environmental history from karst Lake Ocotalito (920 m a.s.l.), which lies in the Lacandon Forest of Chiapas, México. A 5.4-m sediment core was retrieved from a water depth of 23 m. The main factor that shaped ostracodes species assemblages throughout the Holocene was lake level. A total of six species were identified, and the benthic Cytheridella ilosvayi was dominant. Less abundant species included nektobenthic taxa Cypridopsis okeechobei, Heterocypris putei, and Potamocypris sp. and benthic species Darwinula stevensoni and Pseudocandona sp. Wet conditions, high lake levels (>15 m), and low ostracodes abundances characterized the period between ~9540 and ~7820 BP. From ~7750 to 6460 BP, indicators point to stable conditions and intermediate lake levels (~15 m). Greatest ostracodes abundance and diversity occurred from ~6200 to ~4030 BP, during which mainly drier conditions were inferred, interrupted by short, humid periods. Lower abundances and low Sr and δ18O values characterized the period from ~3810 to ~1970 BP and indicate higher lake levels, that is, wetter conditions. Throughout this period, however, a slight trend toward drier conditions was observed. Comparison with paleolimnological studies in other karst lakes from the region suggests mid-altitude aquatic ecosystems may be more sensitive to climate fluctuations than lakes in the lowlands. For instance, stable isotope records from the Lake Ocotalito core display greater ranges. This, however, may simply reflect inter-lake differences in sensitivity, controlled by lake-specific hydrologic factors. The record from Lake Ocotalito fills an important gap in our knowledge of past biotic diversity, paleoclimate, and paleoenvironmental conditions in the northern Neotropics.
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Li, Yuan, Mingrui Qiang, Yanxiang Jin, Li Liu, Aifeng Zhou, and Jiawu Zhang. "Influence of Aquatic Plant Photosynthesis on the Reservoir Effect of Genggahai Lake, Northeastern Qinghai-Tibetan Plateau." Radiocarbon 60, no. 2 (November 16, 2017): 561–69. http://dx.doi.org/10.1017/rdc.2017.127.
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AbstractTerrestrial plant remains in the sediments of lakes from semi-arid and arid regions are rare and therefore the establishment of a sediment chronology depends on accurate assessment of the reservoir effect of the lake water. In a study of Genggahai Lake in the Gonghe Basin, northeastern Qinghai-Tibetan Plateau, we used accelerator mass spectrometry radiocarbon (AMS 14C) dating to determine the age of (1) dissolved inorganic carbon in the water (DICLW), (2) macrophyte remains in the uppermost samples of core sediments, (3) living P. pectinatus in the lake, and (4) dissolved inorganic carbon of spring water in the catchment. The results show that the ages of the DICLW (910 14C yr BP on average) were much younger than the ages of the groundwater (6330 14C yr BP on average), which may result mainly from CO2 exchange between the lake water and the atmosphere. In addition, the 14C ages of DICLW and macrophyte remains in the uppermost core sediments varied from site to site within the lake, which we ascribe to the different photosynthesis rates of Chara spp. and vascular plants. The higher photosynthesis rate of Chara spp. decreases lake-water pCO2, which leads to more atmospheric CO2 being absorbed by the lake water, and thereby greatly reducing the age of carbon species in areas dominated by Chara spp. Although Genggahai Lake is well mixed, the differences between the apparent ages of the lake water are significantly modulated by the photosynthesis intensity of submerged plants.
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Sauer, Hailey M., Trinity L. Hamilton, Rika E. Anderson, Charles E. Umbanhowar, and Adam J. Heathcote. "Diversity and distribution of sediment bacteria across an ecological and trophic gradient." PLOS ONE 17, no. 3 (March 21, 2022): e0258079. http://dx.doi.org/10.1371/journal.pone.0258079.
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The microbial communities of lake sediments have the potential to serve as valuable bioindicators and integrators of watershed land-use and water quality; however, the relative sensitivity of these communities to physio-chemical and geographical parameters must be demonstrated at taxonomic resolutions that are feasible by current sequencing and bioinformatic approaches. The geologically diverse and lake-rich state of Minnesota (USA) is uniquely situated to address this potential because of its variability in ecological region, lake type, and watershed land-use. In this study, we selected twenty lakes with varying physio-chemical properties across four ecological regions of Minnesota. Our objectives were to (i) evaluate the diversity and composition of the bacterial community at the sediment-water interface and (ii) determine how lake location and watershed land-use impact aqueous chemistry and influence bacterial community structure. Our 16S rRNA amplicon data from lake sediment cores, at two depth intervals, data indicate that sediment communities are more likely to cluster by ecological region rather than any individual lake properties (e.g., trophic status, total phosphorous concentration, lake depth). However, composition is tied to a given lake, wherein samples from the same core were more alike than samples collected at similar depths across lakes. Our results illustrate the diversity within lake sediment microbial communities and provide insight into relationships between taxonomy, physicochemical, and geographic properties of north temperate lakes.
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Daxer, Christoph, Jasper Moernaut, Timothy Taylor, Jean Nicolas Haas, and Michael Strasser. "Late Glacial and Holocene sedimentary infill of Lake Mondsee (Eastern Alps, Austria) and historical rockfall activity revealed by reflection seismics and sediment core analysis." Austrian Journal of Earth Sciences 111, no. 1 (September 1, 2018): 111–34. http://dx.doi.org/10.17738/ajes.2018.0008.
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Abstract Glacigenic perialpine lakes can constitute continuous post-last glacial maximum (LGM) geological archives which allow reconstruction of both lake-specific sedimentological processes and the paleoenvironmental setting of lakes. Lake Mondsee is one among several perialpine lakes in the Salzkammergut, Upper Austria, and has been previously studied in terms of paleoclimate, paleolimnology and (paleo)ecology. However, the full extent and environment of Late Glacial to Holocene sediment deposition had remained unknown, and it was not clear whether previously studied core sections were fully representative of 3D sediment accumulation patterns. In this study, the sedimentary infill of Lake Mondsee was examined via high-resolution seismic reflection survey over a 57-km extent (3.5 kHz pinger source) and a sediment core extracted from the deepest part of the lake, with a continuous length of 13.76 m. In the northern basin, seismic penetration is strongly limited in most areas because of abundant shallow gas (causing acoustic blanking). In the deeper areas, the acoustic signal reaches depths of up to 80 ms TWT (two-way travel time), representing a postglacial sedimentary sequence of at least 60-m thickness. Holocene deposits constitute only the uppermost 11.5 m of the sedimentary succession. Postglacial seismic stratigraphy of Lake Mondsee closely resembles those of well-studied French and Swiss perialpine lakes, with our data showing that most of Lake Mondsee’s sedimentary basin infill was deposited within a short time period (between 19,000 BP and 14,500 BP) after the Traun Glacier retreated from the Mondsee area, indicating an average sedimentation rate of about 1.4 cm/yr. Compared to other perialpine lakes, the seismic data from Lake Mondsee reveal little indication of mass movement activities during the Holocene. One exception, however, is rockfalls that originate from a steep cliff, the Kienbergwand, situated on the southern shore of Lake Mondsee, where, in the adjacent part of the lake, seismic profiles show mass transport deposits (MTDs), which extend approximately 450 m from the shore and are mappable over an area of about 45,300 m2. Sediment cores targeting the MTDs show two separate rockfall events. The older event consists of clast-supported angular dolomitic gravels and sands, showing high amounts of fine fraction. The younger event exhibits dolomitic clasts of up to 1.5 cm in diameter, which is mixed within a lacustrine muddy matrix. Radiocarbon dating and correlations with varve-dated sediment cores hint at respective ages of AD 1484 ± 7 for Event 1 and AD 1639 ± 5 for Event 2. As our data show no evidence of larger-scale mass movements affecting Lake Mondsee and its surroundings, we infer that the current-day morphology of the Kienbergwand is the result of infrequent medium-scale rockfalls.
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Reheis, Marith C., David M. Miller, John P. McGeehin, Joanna R. Redwine, Charles G. Oviatt, and Jordon Bright. "Directly dated MIS 3 Lake-Level Record from Lake Manix, Mojave Desert, California, USA." Quaternary Research 83, no. 1 (January 2015): 187–203. http://dx.doi.org/10.1016/j.yqres.2014.11.003.
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AbstractAn outcrop-based lake-level curve, constrained by ~ 70 calibrated 14C ages on Anodonta shells, indicates at least 8 highstands between 45 and 25 cal ka BP within 10 m of the 543-m upper threshold of Lake Manix in the Mojave Desert of southern California. Correlations of Manix highstands with ice, marine, and speleothem records suggest that at least the youngest three highstands coincide with Dansgaard–Oeschger (D–O) stadials and Heinrich events 3 and 4. The lake-level record is consistent with results from speleothem studies in the Southwest that indicate cool wet conditions during D–O stadials. Notably, highstands between 43 and 25 ka apparently occurred at times of generally low levels of pluvial lakes farther north as interpreted from core-based proxies. Mojave lakes may have been supported by tropical moisture sources during oxygen-isotope stage 3, perhaps controlled by southerly deflection of Pacific storm tracks due to weakening of the sea-surface temperature gradient in response to North Atlantic climate perturbations.
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Myers, Krista F., Peter T. Doran, Slawek M. Tulaczyk, Neil T. Foley, Thue S. Bording, Esben Auken, Hilary A. Dugan, et al. "Thermal legacy of a large paleolake in Taylor Valley, East Antarctica, as evidenced by an airborne electromagnetic survey." Cryosphere 15, no. 8 (August 3, 2021): 3577–93. http://dx.doi.org/10.5194/tc-15-3577-2021.
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Abstract. Previous studies of the lakes of the McMurdo Dry Valleys have attempted to constrain lake level history, and results suggest the lakes have undergone hundreds of meters of lake level change within the last 20 000 years. Past studies have utilized the interpretation of geologic deposits, lake chemistry, and ice sheet history to deduce lake level history; however a substantial amount of disagreement remains between the findings, indicating a need for further investigation using new techniques. This study utilizes a regional airborne resistivity survey to provide novel insight into the paleohydrology of the region. Mean resistivity maps revealed an extensive brine beneath the Lake Fryxell basin, which is interpreted as a legacy groundwater signal from higher lake levels in the past. Resistivity data suggest that active permafrost formation has been ongoing since the onset of lake drainage and that as recently as 1500–4000 years BP, lake levels were over 60 m higher than present. This coincides with a warmer-than-modern paleoclimate throughout the Holocene inferred by the nearby Taylor Dome ice core record. Our results indicate Mid to Late Holocene lake level high stands, which runs counter to previous research finding a colder and drier era with little hydrologic activity throughout the last 5000 years.
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Dickman, M., P. Hayes, and J. Fortescue. "A Comparison of Two Indices of Diatom Inferred pH." Water Quality Research Journal 20, no. 1 (February 1, 1985): 9–24. http://dx.doi.org/10.2166/wqrj.1985.002.
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Abstract Autecological studies of diatoms as pH indicators have opened the way to estimating a lake's past pH on the basis of its diatom species compos it ion and relative abundance. Estimating the rate of lake acidification from its sediment subfossil diatoms is possible when these subfossils can be identified and accurately enumerated down the length of the lake sediment core. This technique holds considerable promise in assessing the temporal impact of acid precipitation for acid-sensitive lakes. When diatom inferred pH was regressed against observed pH for 23 lakes located north of Lake Superior a significant (P<0.01) correlation (r=0.71) resulted. Diatom downcore stratigraphy for two of these lakes (lakes Cs & B) indicated that their pH had dropped from 6.3 to 5.3 (Lake Cs) and from 5.6 to 5.3 (Lake B) over the last 20 years. However, when the "B" index was used instead of log alpha, no significant change in downcore diatom inferred pH was apparent for Lake B. We concluded that log alpha was overly sensitive to small changes in the relative abundance of alkaliphilic diatoms. Thus, in lakes where alkaliphilic diatoms are rare, index "B" rather than log alpha should be employed. In lakes of pH 6 or above where the relative abundance of alkaliphilic diatoms is higher (e.g. Cs & Fenton Lakes) index "B" and log alpha provide essentially identical downcore pH profiles.
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Wolfe, Brent, Hedy J. Kling, Gregg J. Brunskill, and Paul Wilkinson. "Multiple Dating of a Freeze Core from Lake 227, an Experimentally Fertilized Lake with Varved Sediments." Canadian Journal of Fisheries and Aquatic Sciences 51, no. 10 (October 1, 1994): 2274–85. http://dx.doi.org/10.1139/f94-231.
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A freeze core taken from Experimental Lakes Area Lake 227 in 1988 contained 321 rhythmically paired, dark and light laminations in the upper 60.7 cm. Tape peels revealed cyclic, seasonal abundance peaks in organic and inorganic remains, which suggested that the couplets are varves. However, comparison between varve chronology and 22 yr of experimental changes in phosphorus (P) and nitrogen (N) loading and their influence on the planktonic community confirmed that the most recent varve-year estimates were 5 or 6 yr too old; this was caused by irregular sedimentation and multiple algal blooms resulting from experimental fertilization since 1969, and indistinct laminations that hampered precise couplet identification and separation. Dated horizons determined from biostratigraphic markers were used to generate compatible profiles between 1-cm slices of Lake 227 137Cs flux and reference fallout records. Nutrient concentration profiles were less helpful, as increases in carbon, N, and, P were gradual and no distinct horizon was identified as a clear marker of eutrophication. Long-term assessment of the varve chronology using 210Pb was hindered by experimental additions of 226Ra to the lake in 1970, although similar sedimentation rates from varve years 1860–1934 suggested that the varve and the deep part of the 210Pb chronologies were comparable.
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Nakagawa, Takeshi. "Lake Suigetsu 2006 Varved Sediment Core Project." PAGES news 20, no. 2 (December 2012): 70–71. http://dx.doi.org/10.22498/pages.20.2.70.
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Safe, Abdolah, Fatemeh Sabokkhiz, Mohamad Hosein Ramesht, Morteza Djamali, and Abdolmajid Naderi Beni. "Study Clastic Sediments and Evaporite Deposits’ Changes in the Sedimentary Core Lake Maharlou, Iran." Modern Applied Science 10, no. 4 (February 13, 2016): 1. http://dx.doi.org/10.5539/mas.v10n4p1.
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The continental environments, lakes are proper for deposition locations of evaporites. Evaporite minerals are formed wherever the evaporation rate is more than incoming water to the basin. In this article the evaporate deposits (Calcite, Gypsum and Halite) are studied in a sedimentary core of Lake Maharlou, Zagros Mountains, South of Iran. The core sample treated for getting Magnetic Susceptibility values along with the core as well as basic sedimentological data including grain size, Total Organic Matter and carbonate contents. NaCl is determin ed by gravimetric analysis. Loss on Ignition is applied to measure and estimate the amount of (OC), (Ca) and (SO4) mineralogy of which is determined by SEM method. The exists a direct relation between evaporation deposit formation of lake water level reduction. Accordingly, the change in the sediment stratum indicating the level of evaporations. The results indicate a lower extant of gypsum than Ca and NaCl. The sequence of layers principle, changes in the shoreline (lake water level fluctuations) with respect to stratum zonation. Magnetic susceptibility level is directly related to the Silt layer thickness but also there is an indirect relation with the level of organically rich sediments’ occurrence and abundance.
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Horvatinčić, Nada, Jadranka Barešić, Slavica Babinka, Bogomil Obelić, Ines Krajcar Bronić, Polona Vreča, and Axel Suckow. "Towards a Deeper Understanding of How Carbonate Isotopes (14C, 13C, 18O) Reflect Environmental Changes: A Study with Recent 210Pb-Dated Sediments of the Plitvice Lakes, Croatia." Radiocarbon 50, no. 2 (2008): 233–53. http://dx.doi.org/10.1017/s0033822200033543.
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Five short cores (top 40–45 cm of sediment) from 4 lakes of the Plitvice Lakes system (Croatia) were measured for 210Pb, 137Cs, a14C, δ13C, and δ18O in order to study the influence of environmental changes on the sediment system in small and large lakes. Sediment chronology based on the constant flux (CF) 210Pb model was the most reliable. Lake sediments consisted mainly of autochthonous carbonates with higher sedimentation rates in small lakes. Sediments from 2 large lakes, Prošće and Kozjak, showed constant stable isotope profiles for the carbonate fraction and full agreement between the 137Cs and 210Pb chronologies. Sediments from 2 small lakes, Gradinsko and Kaluderovac, showed synchronous increases in 14C and δ13C and disturbed 137Cs records. All lakes showed an increase in a14C in the carbonate sediments above the first occurrence of 137Cs, which was interpreted as a damped (~10 pMC increase in a14C) and decades-delayed consequence of the bomb-induced increase in a14C in atmospheric CO2. For the small lakes, increased δ13C in the last 2 decades and part of the a14C increase is probably due to an increase in primary productivity, which enhanced biologically induced calcite precipitation with concomitant changes in the carbon isotopic composition of carbonate sediments. δ13C values of a near-shore sediment core close to the confluence of one of the tributaries of Lake Kozjak showed that the carbonates in this core are a mixture of autochthonous and eroded allochthonous mineral carbonate. This core had a higher fraction of organic material. The sedimentation rate at this core site was high, but rates could not be quantified by 210Pb, 137Cs, or 14C.
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Swadling, Kerrie M., Herbert J. G. Dartnall, John A. E. Gibson, Émilie Saulnier-Talbot, and Warwick F. Vincent. "Fossil Rotifers and the Early Colonization of an Antarctic Lake." Quaternary Research 55, no. 3 (May 2001): 380–84. http://dx.doi.org/10.1006/qres.2001.2222.
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AbstractEarly Holocene sediments from a continental Antarctic lake (Ace Lake, Vestfold Hills, East Antarctica) contained abundant fossil rotifers of the genus Notholca. The fossil is similar to specimens of Notholca sp. present in modern-day Ace Lake and other fresh and brackish lakes of the Vestfold Hills. Cyanobacteria and protists (chrysophyte cysts, dinoflagellate cysts, and rhizopod tests) were also recovered from the core samples. These sediments were deposited early in the freshwater phase of Ace Lake, soon after deglaciation of the area. The occurrence of this trophically diverse assemblage of organisms at an early stage in the evolution of the lake suggests either that they were part of an endemic Antarctic flora and fauna which pre-dated the last glacial maximum and survived in glacial refugia or that efficient intercontinental dispersal had occurred.
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STARRATT, SCOTT W., and R. SCOTT ANDERSON. "Preliminary Report on the Late Pleistocene and Holocene Diatoms of Swamp Lake, Yosemite National Park, California, USA." Phytotaxa 127, no. 1 (August 29, 2013): 128. http://dx.doi.org/10.11646/phytotaxa.127.1.14.
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Swamp Lake, Yosemite National Park, is the only known lake in California containing long sequences of varved sediments and thus has the potential to provide a high-resolution record of climate variability. This preliminary analysis of the diatom assemblages from a 947-cm-long composite sediment core (freeze core FZ02–05; 0–67 cm, Livingstone core 02–05; 53–947 cm) shows that the lake has been freshwater, oligotrophic, and circumneutral to alkaline throughout its ~16,000-year-long history. The first sediments deposited in the lake show that the vegetation in the watershed was sparse, allowing organic matter-poor silt and clay to be deposited in the basin. The basin filled quickly to a depth of at least 5 m and remained at least that deep for most of the sediment record. Several short intervals provided evidence of large fluctuations in lake level during the Holocene. The upper 50 cm of the core contains evidence of the Medieval Climate Anomaly and Little Ice Age.
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Marks, Leszek, Alaa Salem, Fabian Welc, Jerzy Nitychoruk, Zhongyuan Chen, Abdelfattah Zalat, Aleksandra Majecka, Marta Chodyka, Marcin Szymanek, and Anna Tołoczko-Pasek. "Preliminary Report on Unique Laminated Holocene Sediments from the Qarun Lake in Egypt." Studia Quaternaria 33, no. 1 (June 1, 2016): 35–46. http://dx.doi.org/10.1515/squa-2016-0004.
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Abstract The Lake Qarun (Faiyum Oasis, northern Egypt) is a relic of the much larger Holocene lake. Past lake levels and extensions were reconstructed, based on setting of archaeological sites scattered along northern paleoshores of the ancient lake. However, geoarcheological works did not yield enough data to establish continuous environmental history of the lake. A deep drilling FA-1 on the southeastern shore of the lake, performed in 2014, supplied with a core, 26 m long that is the one of the longest lake sediment cores in northeastern Africa. The basal section of the core consisted of thin-laminated diatom marly deposits, underlain at the Late Pleistocene/Holocene boundary by coarse-grained sands. The sediment lamine were quite well developed, especially in the lower part of the core. Preliminary results indicated annually deposited sediment sequence with seasonality signals provided by microlamine of diatoms, calcite, organic matter and clastic material. Early Holocene varved sediments from the Faiyum Oasis supplied with exceptional paleoenvironmental data for northeastern Africa, which enriched a record from previous logs drilled at the southwestern margin of the Qarun Lake.
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Olteanu, Radu Lucian, Cristiana Radulescu, Petre Bretcan, Inga Zinicovscaia, Otilia Culicov, Konstantin Vergel, Danut Tanislav, et al. "Geochemical Responses to Natural and Anthropogenic Settings in Salt Lakes Sediments from North-Eastern Romanian Plain." International Journal of Environmental Research and Public Health 20, no. 2 (January 4, 2023): 935. http://dx.doi.org/10.3390/ijerph20020935.
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Chemical analysis was performed on sediment core samples collected from three salt lakes, Amara Lake, Caineni Lake, and Movila Miresii Lake, located in the northeast of the Romanian Plain. The concentration of 10 main elements, 6 heavy metals (HMs), 8 rare earth elements (REEs), and 10 trace elements (TEs)—determined using neutron activation analysis (NAA)—showed variability dependent on the depth sections, lake genesis and geochemical characteristics (oxbow, fluvial harbor/liman and loess saucer type). The assessment of pollution indices (contamination factor, pollution load index, geoaccumulation index, and enrichment factor) highlighted low and moderate degrees of contamination for most of the investigated elements. Principal component analysis (PCA) extracted three principal components, explaining 70.33% (Amara Lake), 79.92% (Caineni Lake), and 71.42% (Movila Miresii Lake) of the observed variability. The principal components extracted were assigned to pedological contribution (37.42%—Amara Lake, 55.88%—Caineni Lake, and 15.31%—Movila Miresii Lake), salts depositions (due to the lack of a constant supply of freshwater and through evaporation during dry periods), atmospheric deposition (19.19%—Amara Lake, 13.80%—Caineni Lake, and 10.80%—Movila Miresii Lake), leaching from soil surface/denudation, rock weathering, and mixed anthropogenic input (e.g., agricultural runoff, wastewater discharges) (13.72%—Amara Lake, 10.24%—Caineni Lake, and 45.31%—Movila Miresii Lake).
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CVETKOSKA, ALEKSANDRA, ZLATKO LEVKOV, and PAUL B. HAMILTON. "Surirella subrotunda sp. nov. and Surirella parahelvetica sp. nov., two new diatom (Bacillariophyta) species from Lake Prespa, Macedonia." Phytotaxa 156, no. 3 (January 16, 2014): 145. http://dx.doi.org/10.11646/phytotaxa.156.3.5.
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The genus Surirella is highly diverse and many taxa are reported as endemic, especially from ancient lakes and tropical continental regions. In ancient Lake Ohrid, 25 different Surirella species have been identified by different authors, five are considered to be endemic for the lake. In contrast, research on its sister Lake Prespa has been less rigorous and data for recent and fossil species of Surirella is very sparse. The number of Surirella taxa reported from Lake Prespa is 11; only one is considered an endemic for both lakes, Ohrid and Prespa. In this study, taxa from the genus Surirella were observed in a number of recent and fossil samples from Lake Prespa. Two taxa possess unique characters that distinguish them from known species. Their formal descriptions, based on detailed LM and SEM observations, are presented here. Surirella subrotunda sp. nov. is differentiated from other similar species by its valve outline, size, and shape of median area; it has been observed only in fossil diatom samples from core Co1215 recovered from Lake Prespa. Surirella parahelvetica sp. nov. is distinguished by its size, valve outline, number of alar canals and stria density.
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Liu, Lina, Xiaohuan Hou, Xiaoshan Yu, Nannan Wang, Yanrong Zhang, and Xianyong Cao. "Vegetation and environmental changes since the Last Glacial Maximum inferred from a lake core from Saiyong Co, central Tibetan Plateau." Holocene 32, no. 6 (March 7, 2022): 543–53. http://dx.doi.org/10.1177/09596836221080763.
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Pollen and grain-size records from a small lake (Saiyong Co) in the source region of the Yangtze River, central Tibetan Plateau are presented and used to reveal vegetation and lake environmental history since the Last Glacial Maximum (LGM). Results indicate that the Saiyong Co basin was a marshy environment with sparse vegetation cover from 21.3 to 6.6 cal. ka BP, before becoming a lake. Highest water level is inferred for 3.9–3.4 cal. ka BP followed by a gradual drying up until 100 years ago. Since then, the lake level has begun to rise again. Pollen spectra are dominated by Artemisia, Poaceae and Cyperaceae, and vegetation changes are mainly reflected by changes in the proportion of these three taxa, especially Artemisia and Cyperaceae. Two major events occurred at 3.9 cal. ka BP and 1.2 cal. ka BP, in response to climate change. Our results also reveal that lake-level changes affect the interpretation of the pollen assemblages due to the relationship between lake size and the pollen source area. Local pollen became the dominant component in pollen assemblages at 0.6 cal. ka BP when the lake level fell to below a certain depth. A higher percentage of Cyperaceae marks the lake’s retreat and reflects the local vegetation around Saiyong Co during 0.6 to ~0.1 cal. ka BP. In the last 100 years, a high value of Cyperaceae is linked to a wetter climate with no obvious evidence for human activities. Our results have important implications for the interpretation of fossil pollen assemblages from small lakes as the size of the lake through its history also needs to be known to prevent erroneous interpretations of the pollen data.
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Bennett, Shannon N., Martin L. Adamson, and Leo Margolis. "Long-term changes in parasites of sockeye salmon (Oncorhynchus nerka) smolts." Canadian Journal of Fisheries and Aquatic Sciences 55, no. 4 (April 1, 1998): 977–86. http://dx.doi.org/10.1139/f97-295.
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Parasites were examined in 41 annual samples of sockeye salmon (Oncorhynchus nerka) juveniles originating from lakes in British Columbia: Chilko and Shuswap. Nine species of parasitic helminths and two species of parasitic Crustacea were recovered from various organs. The number of species ranged from three to nine per year. Most (94%) parasites belonged to three tapeworm species, identified as core to the parasite community because they also infected the most hosts. Two of these cestode species are probably maintained by resident freshwater hosts in the lakes. Positive numerical associations were observed between four parasite species pairs. Parasite communities in both lakes were composed of similar species, with the exception of three rare Chilko Lake species that were never recovered from Shuswap Lake. Parasites were often as variable within stock (temporally) as between stocks (geographically), except for the prevalence of Eubothrium sp. and Neoechinorhynchus sp. and mean annual intensity of Proteocephalus sp. and encysted digenetic metacercariae, which were greater at Chilko Lake than at Shuswap Lake. Discrimination between the two lakes based on their parasite community is possible only in extreme cases of infection and thus is of limited use to fisheries officers attempting to distinguish between these stocks.
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Heslop, J. K., K. M. Walter Anthony, A. Sepulveda-Jauregui, K. Martinez-Cruz, A. Bondurant, G. Grosse, and M. C. Jones. "Thermokarst lake methanogenesis along a complete talik profile." Biogeosciences 12, no. 14 (July 24, 2015): 4317–31. http://dx.doi.org/10.5194/bg-12-4317-2015.
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Abstract. Thermokarst (thaw) lakes emit methane (CH4) to the atmosphere formed from thawed permafrost organic matter (OM), but the relative magnitude of CH4 production in surface lake sediments vs. deeper thawed permafrost horizons is not well understood. We assessed anaerobic CH4 production potentials from various depths along a 590 cm long lake sediment core that captured the entire sediment package of the talik (thaw bulb) beneath the center of an interior Alaska thermokarst lake, Vault Lake, and the top 40 cm of thawing permafrost beneath the talik. We also studied the adjacent Vault Creek permafrost tunnel that extends through ice-rich yedoma permafrost soils surrounding the lake and into underlying gravel. Our results showed CH4 production potentials were highest in the organic-rich surface lake sediments, which were 151 cm thick (mean ± SD: 5.95 ± 1.67 μg C–CH4 g dw−1 d−1; 125.9 ± 36.2 μg C–CH4 g C−1org d−1). High CH4 production potentials were also observed in recently thawed permafrost (1.18 ± 0.61 μg C–CH4g dw−1 d−1; 59.60± 51.5 μg C–CH4 g C−1org d−1) at the bottom of the talik, but the narrow thicknesses (43 cm) of this horizon limited its overall contribution to total sediment column CH4 production in the core. Lower rates of CH4 production were observed in sediment horizons representing permafrost that has been thawing in the talik for a longer period of time. No CH4 production was observed in samples obtained from the permafrost tunnel, a non-lake environment. Our findings imply that CH4 production is highly variable in thermokarst lake systems and that both modern OM supplied to surface sediments and ancient OM supplied to both surface and deep lake sediments by in situ thaw and shore erosion of yedoma permafrost are important to lake CH4 production.
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Heslop, J. K., K. M. Walter Anthony, A. Sepulveda-Jauregui, K. Martinez-Cruz, A. Bondurant, G. Grosse, and M. C. Jones. "Thermokarst-lake methanogenesis along a complete talik profile." Biogeosciences Discussions 12, no. 6 (March 24, 2015): 4865–905. http://dx.doi.org/10.5194/bgd-12-4865-2015.
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Abstract. Thermokarst (thaw) lakes emit methane (CH4) to the atmosphere formed from thawed permafrost organic matter (OM), but the relative magnitude of CH4 production in surface lake sediments vs. deeper thawed permafrost horizons is not well understood. We assessed anaerobic CH4 production potentials from various depths along a 590 cm long lake sediment core that captured the entire sediment package of the talik (thaw bulb) beneath the center of an interior Alaska thermokarst lake, Vault Lake, and the top 40 cm of thawing permafrost beneath the talik. We also studied the adjacent Vault Creek permafrost tunnel that extends through ice-rich yedoma permafrost soils surrounding the lake and into underlying gravel. Our results showed CH4 production potentials were highest in the organic-rich surface lake sediments, which were 151 cm thick (mean ± SD 5.95 ± 1.67 μg C-CH4 g dw−1 d−1; 125.9± 36.2 μg C-CH4 g C−1org d−1). High CH4 production potentials were also observed in recently-thawed permafrost (1.18± 0.61 μg C-CH4g dw−1 d−1; 59.60± 51.5 μg C-CH4 g C−1org d−1) at the bottom of the talik, but the narrow thicknesses (43 cm) of this horizon limited its overall contribution to total sediment column CH4 production in the core. Lower rates of CH4 production were observed in sediment horizons representing permafrost that has been thawed in the talik for longer periods of time. No CH4 production was observed in samples obtained from the permafrost tunnel, a non-lake environment. Our findings imply that CH4 production is highly variable in thermokarst-lake systems and that both modern OM supplied to surface sediments and ancient OM supplied to both surface and deep lake sediments by in situ thaw as well as shore erosion of yedoma permafrost are important to lake CH4 production.
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Ku, Teh-Lung, Shangde Luo, Tim K. Lowenstein, Jianren Li, and Ronald J. Spencer. "U-Series Chronology of Lacustrine Deposits in Death Valley, California." Quaternary Research 50, no. 3 (November 1998): 261–75. http://dx.doi.org/10.1006/qres.1998.1995.
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Uranium-series dating on a 186-m core (DV93-1) drilled from Badwater Basin in Death Valley, California, and on calcareous tufas from nearby strandlines shows that Lake Manly, the lake that periodically flooded Death Valley during the late Pleistocene, experienced large fluctuations in depth and chemistry over the last 200,000 yr. Death Valley has been occupied by a long-standing deep lake, perennial shallow saline lakes, and a desiccated salt pan similar to the modern valley floor. The average sedimentation rate of about 1 mm/yr for core DV93-1 was punctuated by episodes of more-rapid accumulation of halite. Arid conditions similar to the modern conditions prevailed during the entire Holocene and between 120,000 and 60,000 yr B.P. From 35,000 yr B.P. to the beginning of the Holocene, a perennial saline lake existed, over 70 m at its deepest. A much deeper and longer lasting perennial Lake Manly existed from about 185,000 to 128,000 yr B.P., with water depths reaching about 175 m, if not 330 m. This lake had two significant “dry” excursions of 102–103yr duration about 166,000 and 146,000 yr B.P., and it began to shrink to the point of halite precipitation between 128,000 and 120,000 yr B.P. The two perennial lake periods correspond to marine oxygen isotopic stages (OIS) 2 and 6. Based on the shoreline tufa ages, we do not rule out the possible existence ∼200,000 yr ago of yet a third perennial lake comparable in size to the OIS 6 lake. The234U/238U data suggest that U in tufa owes its origin mainly to Ca-rich springs fed by groundwater that emanated along lake shorelines in southern Death Valley, and that an increase of this spring-water input relative to the river-water input apparently occurred during OIS 6.
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Wu, Chao, Xiaodong Wu, Xuguang Ge, Lian Feng, Ya Tan, Jiuyun Yang, Weixiang Ren, and Min Zou. "Characteristics of Dissolved Organic Matter in Sediments of Typical Lakes in Southeastern Hubei Province, China." International Journal of Environmental Research and Public Health 19, no. 12 (June 16, 2022): 7402. http://dx.doi.org/10.3390/ijerph19127402.
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This study aimed to reveal the distribution characteristics and sources of dissolved organic matter (DOM) in sediments of typical lakes in the southeastern of the Hubei province and provide a reference for pollution control of eutrophic lakes. The sediments of four typical lakes (Liangzi, Baoan, Daye, and Qingshan) in the southeastern of the Hubei Province were investigated in May 2019. Ultraviolet-visible (UV-Vis) absorption spectroscopy and excitation-emission matrixes characteristics of DOM were obtained by UV-Vis spectrophotometry and three-dimensional fluorescence spectroscopy. Moreover, the DOM fluorescence components were resolved by parallel factor analysis (PARAFAC). The results showed that: (1) The absorption coefficient a350 in surface sediments followed the order: Baoan Lake (16.99 ± 3.82 m−1) > Qingshan Lake (15.37 ± 3.8 m−1) > Liangzi Lake (12.54 ± 5.58 m−1) > Daye Lake (12.43 ± 1.43 m−1). Specifically, with increasing depth in the sediment cores, a350 increased and then gradually decreased in Daye Lake and Baoan Lake, but fluctuated in Liangzi Lake and Qingshan Lake with a roughly decreasing trend. (2) Two humic-like components (C1, C2) and one protein-like component (C3) were identified via PARAFAC. This analysis also showed that the surface sediment fluorescent dissolved organic matter (FDOM) was dominated by protein-like, while the sediment core FDOM was dominated by humic-like in Liangzi Lake. The proportion of humic-like in FDOM was higher than protein-like in surface sediments and sediment cores of Baoan, Daye, and Qingshan Lakes. (3) The DOM of surface sediments in the Liangzi Lake comprised mostly autochthonous components, mainly produced by the vital activities of aquatic organisms. The DOM of surface sediments in Baoan Lake and Qingshan Lake showed weak humic and moderate autochthonous characteristics. The humification of DOM in sediment cores of Liangzi, Baoan, and Qingshan Lakes gradually decreased from depth to the surface. The DOM in surface sediments of Daye Lake had strong humic and moderate autochthonous characteristics. (4) In general, the DOM of lake sediments in southeastern Hubei Province has dual-contribution characteristics representing terrigenous and endogenous sources. In the restoration and treatment of lake ecology, both internal and terrestrial pollution should be considered. At the same time, it is noteworthy that cyanobacteria depletion and aquatic residues caused potential internal pollution.