scholarly journals The SCOPSCO drilling project recovers more than 1.2 million years of history from Lake Ohrid

2014 ◽  
Vol 17 ◽  
pp. 19-29 ◽  
Author(s):  
B. Wagner ◽  
T. Wilke ◽  
S. Krastel ◽  
G. Zanchetta ◽  
R. Sulpizio ◽  
...  

Abstract. The Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) project is an international research initiative to study the influence of major geological and environmental events on the biological evolution of lake taxa. SCOPSCO drilling campaigns were carried out in 2011 and 2013. In 2011 we used gravity and piston coring at one of the five proposed drill sites, and in 2013 we undertook deep drilling with the Deep Lake Drilling System (DLDS) of Drilling, Observation and Sampling of the Earth's Continental Crust (DOSECC). In April and May 2013, a total of 2100 m sediments were recovered from four drill sites with water depths ranging from 125 to 260 m. The maximum drill depth was 569 m below the lake floor in the centre of the lake. By retrieving overlapping sediment sequences, 95% of the sediment succession was recovered. Initial data from borehole logging, core logging and geochemical measurements indicate that the sediment succession covers >1.2 million years (Ma) in a quasi-continuous sequence. These early findings suggest that the record from Lake Ohrid will substantially improve the knowledge of long-term environmental change and short-term geological events in the northeastern Mediterranean region, which forms the basis for improving understanding of the influence of major geological and environmental events on the biological evolution of endemic species.

2016 ◽  
Vol 13 (6) ◽  
pp. 1801-1820 ◽  
Author(s):  
Jack H. Lacey ◽  
Melanie J. Leng ◽  
Alexander Francke ◽  
Hilary J. Sloane ◽  
Antoni Milodowski ◽  
...  

Abstract. Lake Ohrid (Macedonia/Albania) is an ancient lake with unique biodiversity and a site of global significance for investigating the influence of climate, geological, and tectonic events on the generation of endemic populations. Here, we present oxygen (δ18O) and carbon (δ13C) isotope data from carbonate over the upper 243 m of a composite core profile recovered as part of the Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) project. The investigated sediment succession covers the past ca. 637 ka. Previous studies on short cores from the lake (up to 15 m, < 140 ka) have indicated the total inorganic carbon (TIC) content of sediments to be highly sensitive to climate change over the last glacial–interglacial cycle. Sediments corresponding to warmer periods contain abundant endogenic calcite; however, an overall low TIC content in glacial sediments is punctuated by discrete bands of early diagenetic authigenic siderite. Isotope measurements on endogenic calcite (δ18Oc and δ13Cc) reveal variations both between and within interglacials that suggest the lake has been subject to palaeoenvironmental change on orbital and millennial timescales. We also measured isotope ratios from authigenic siderite (δ18Os and δ13Cs) and, with the oxygen isotope composition of calcite and siderite, reconstruct δ18O of lake water (δ18Olw) over the last 637 ka. Interglacials have higher δ18Olw values when compared to glacial periods most likely due to changes in evaporation, summer temperature, the proportion of winter precipitation (snowfall), and inflow from adjacent Lake Prespa. The isotope stratigraphy suggests Lake Ohrid experienced a period of general stability from marine isotope stage (MIS) 15 to MIS 13, highlighting MIS 14 as a particularly warm glacial. Climate conditions became progressively wetter during MIS 11 and MIS 9. Interglacial periods after MIS 9 are characterised by increasingly evaporated and drier conditions through MIS 7, MIS 5, and the Holocene. Our results provide new evidence for long-term climate change in the northern Mediterranean region, which will form the basis to better understand the influence of major environmental events on biological evolution within Lake Ohrid.


2016 ◽  
Vol 21 ◽  
pp. 29-40 ◽  
Author(s):  
James M. Russell ◽  
Satria Bijaksana ◽  
Hendrik Vogel ◽  
Martin Melles ◽  
Jens Kallmeyer ◽  
...  

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.


2017 ◽  
Vol 32 (1) ◽  
pp. 25 ◽  
Author(s):  
Johanna Carolina Vega Sequeda ◽  
Sven Zea ◽  
Gladys Bernal

El incremento en la frecuencia e intensidad de eventos oceánicos extremos limita la capacidad de recuperación de los ecosistemas, amenazando su subsistencia. Con el fin de entender la relación entre la estructura y salud arrecifal y los eventos extremos ambientales, se analizaron series de datos ambientales de las islas del Rosario (e.g., temperatura del mar, caudal y/o salinidad, turbidez), en comparación con cobertura coralina y signos de deterioro (e.g., blanqueamiento, enfermedades). En las series de tiempo de las variables ambientales se calcularon los eventos oceánicos que excedieron un umbral estadístico, estableciendo su intensidad, duración y frecuencia. Para los atributos de la comunidad, se evaluaron dos estaciones del Sistema Nacional de Monitoreo de Arrecifes Coralinos en Colombia (SIMAC), en dos ventanas temporales (largo plazo, 1998–2013 y corto plazo, 2013 - 2014). Los eventos extremos de temperatura superficial del mar, el caudal de descarga continental y la turbidez asociada fueron las principales variables relacionadas con la reducción de la cobertura coralina. El blanqueamiento masivo de 2005 y otros eventos posteriores dieron como resultado una reducción de la cobertura coralina entre 2004 y 2010. En el corto plazo no se registraron fuertes eventos extremos ni cambios en las formaciones coralinas, si bien el estrés térmico y las reducciones de salinidad en la época de lluvias estuvieron asociados con un ligero blanqueamiento en noviembre de 2014. Aunque los signos de deterioro sean bajos, es importante considerarlos, ya que la sinergia entre perturbaciones continuas puede conllevar a una pérdida de cobertura del coral.  Effect of extreme oceanic events in the coral formations of Islas del Rosario,  Colombian CaribbeanThe increase in frequency and intensity of extreme oceanic events limits the capacity of recovery of ecosystems, threatening their subsistence. Thus, in order to understand the relationship between coral health and extreme environmental events, data on sea temperature, runoff and / or salinity, turbidity were analyzed in the Islas del Rosario in comparison with coral cover, and coral signs of deterioration (e.g., bleaching, coral diseases). In the time series of environmental variables, oceanic events that exceeded a statistical threshold were calculated, establishing their intensity, duration and frequency. The attributes of the community were studied through observations in two stations of the National Coral Reef Monitoring System in Colombia (SIMAC), assessed in two time windows (long term, 1998-2013 and short term, 2013-2014). The extreme events of sea surface temperature, river discharge and associated turbidity, were the main variables related to the reduction of coral cover. The massive coral bleaching of 2005 and other subsequent events resulted in a reduction in coral coverage between 2004 and 2010. During the short-term observations there were no strong extreme events or changes in coral formations, although thermal stress and reductions in salinity in the rainy season were associated with a slight bleaching in November 2014. Although the signs of deterioration are low, it is important to consider them, since the synergy between continuous disturbances can lead to a loss of coral cover.


2018 ◽  
Vol 72 (4) ◽  
pp. 905-936 ◽  
Author(s):  
Vally Koubi ◽  
Tobias Böhmelt ◽  
Gabriele Spilker ◽  
Lena Schaffer

AbstractMigration is likely to be a key factor linking climate change and conflict. However, our understanding of the factors behind and consequences of migration is surprisingly limited. We take this shortcoming as a motivation for our research and study the relationship between environmental migration and conflict at the micro level. In particular, we focus on environmental migrants' conflictperceptions. We contend that variation in migrants' conflict perception can be explained by the type of environmental event people experienced in their former home, whether gradual, and long-term or sudden-onset, short-term environmental changes. We develop this argument before quantitatively analyzing newly collected micro-level data on intra-state migration from five developing countries. The results emphasize that migrants who experienced gradual, long-term environmental events in their former homes are more likely to perceive conflict in their new location than those having experienced sudden, short-term environmental events. These findings are in line with our theoretical argument that environmental migrants who suffer from environmentally induced grievances are ultimately more likely toperceiveconflict and challenges in their new locations.


2015 ◽  
Vol 12 (16) ◽  
pp. 13427-13481 ◽  
Author(s):  
J. H. Lacey ◽  
M. J. Leng ◽  
A. Francke ◽  
H. J. Sloane ◽  
A. Milodowski ◽  
...  

Abstract. Lake Ohrid (Macedonia/Albania) is an ancient lake with a unique biodiversity and a site of global significance for investigating the influence of climate, geological and tectonic events on the generation of endemic populations. Here, we present oxygen (δ18O) and carbon (δ13C) isotope data on carbonate from the upper ca. 248 m of sediment cores recovered as part of the Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) project, covering the past 640 ka. Previous studies on short cores from the lake (up to 15 m, < 140 ka) have indicated the Total Inorganic Carbon (TIC) content of sediments to be highly sensitive to climate change over the last glacial–interglacial cycle, comprising abundant endogenic calcite through interglacials and being almost absent in glacials, apart from discrete bands of early diagenetic authigenic siderite. Isotope measurements on endogenic calcite (δ18Oc and δ13Cc) reveal variations both between and within interglacials that suggest the lake has been subject to hydroclimate fluctuations on orbital and millennial timescales. We also measured isotopes on authigenic siderite (δ18Os and δ13Cs) and, with the δ18OCc and δ18Os, reconstruct δ18O of lakewater (δ18Olw) through the 640 ka. Overall, glacials have lower δ18Olw when compared to interglacials, most likely due to cooler summer temperatures, a higher proportion of winter precipitation (snowfall), and a reduced inflow from adjacent Lake Prespa. The isotope stratigraphy suggests Lake Ohrid experienced a period of general stability through Marine Isotope Stage (MIS) 15 to MIS 13, highlighting MIS 14 as a particularly warm glacial, and was isotopically freshest during MIS 9. After MIS 9, the variability between glacial and interglacial δ18Olw is enhanced and the lake became increasingly evaporated through to present day with MIS 5 having the highest average δ18Olw. Our results provide new evidence for long-term climate change in the northern Mediterranean region, which will form the basis to better understand the influence of major environmental events on biological evolution within the lake.


2016 ◽  
Vol 39 ◽  
Author(s):  
Mary C. Potter

AbstractRapid serial visual presentation (RSVP) of words or pictured scenes provides evidence for a large-capacity conceptual short-term memory (CSTM) that momentarily provides rich associated material from long-term memory, permitting rapid chunking (Potter 1993; 2009; 2012). In perception of scenes as well as language comprehension, we make use of knowledge that briefly exceeds the supposed limits of working memory.


Author(s):  
D.E. Loudy ◽  
J. Sprinkle-Cavallo ◽  
J.T. Yarrington ◽  
F.Y. Thompson ◽  
J.P. Gibson

Previous short term toxicological studies of one to two weeks duration have demonstrated that MDL 19,660 (5-(4-chlorophenyl)-2,4-dihydro-2,4-dimethyl-3Hl, 2,4-triazole-3-thione), an antidepressant drug, causes a dose-related thrombocytopenia in dogs. Platelet counts started to decline after two days of dosing with 30 mg/kg/day and continued to decrease to their lowest levels by 5-7 days. The loss in platelets was primarily of the small discoid subpopulation. In vitro studies have also indicated that MDL 19,660: does not spontaneously aggregate canine platelets and has moderate antiaggregating properties by inhibiting ADP-induced aggregation. The objectives of the present investigation of MDL 19,660 were to evaluate ultrastructurally long term effects on platelet internal architecture and changes in subpopulations of platelets and megakaryocytes.Nine male and nine female beagle dogs were divided equally into three groups and were administered orally 0, 15, or 30 mg/kg/day of MDL 19,660 for three months. Compared to a control platelet range of 353,000- 452,000/μl, a doserelated thrombocytopenia reached a maximum severity of an average of 135,000/μl for the 15 mg/kg/day dogs after two weeks and 81,000/μl for the 30 mg/kg/day dogs after one week.


2020 ◽  
Vol 29 (4) ◽  
pp. 710-727
Author(s):  
Beula M. Magimairaj ◽  
Naveen K. Nagaraj ◽  
Alexander V. Sergeev ◽  
Natalie J. Benafield

Objectives School-age children with and without parent-reported listening difficulties (LiD) were compared on auditory processing, language, memory, and attention abilities. The objective was to extend what is known so far in the literature about children with LiD by using multiple measures and selective novel measures across the above areas. Design Twenty-six children who were reported by their parents as having LiD and 26 age-matched typically developing children completed clinical tests of auditory processing and multiple measures of language, attention, and memory. All children had normal-range pure-tone hearing thresholds bilaterally. Group differences were examined. Results In addition to significantly poorer speech-perception-in-noise scores, children with LiD had reduced speed and accuracy of word retrieval from long-term memory, poorer short-term memory, sentence recall, and inferencing ability. Statistically significant group differences were of moderate effect size; however, standard test scores of children with LiD were not clinically poor. No statistically significant group differences were observed in attention, working memory capacity, vocabulary, and nonverbal IQ. Conclusions Mild signal-to-noise ratio loss, as reflected by the group mean of children with LiD, supported the children's functional listening problems. In addition, children's relative weakness in select areas of language performance, short-term memory, and long-term memory lexical retrieval speed and accuracy added to previous research on evidence-based areas that need to be evaluated in children with LiD who almost always have heterogenous profiles. Importantly, the functional difficulties faced by children with LiD in relation to their test results indicated, to some extent, that commonly used assessments may not be adequately capturing the children's listening challenges. Supplemental Material https://doi.org/10.23641/asha.12808607


2019 ◽  
Vol 25 ◽  
pp. 114
Author(s):  
Alyssa Dufour ◽  
Setareh Williams ◽  
Richard Weiss ◽  
Elizabeth Samelson

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