scholarly journals Ecosystem regimes and responses in a coupled ancient lake system from MIS 5b to present: the diatom record of lakes Ohrid and Prespa

2016 ◽  
Vol 13 (10) ◽  
pp. 3147-3162 ◽  
Author(s):  
Aleksandra Cvetkoska ◽  
Elena Jovanovska ◽  
Alexander Francke ◽  
Slavica Tofilovska ◽  
Hendrik Vogel ◽  
...  
Keyword(s):  
Climate Change ◽  
Chemical Properties ◽  
Regime Shifts ◽  
Interglacial Period ◽  
Glacial Cycle ◽  
Last Interglacial ◽  
Lake Ohrid ◽  
Lake Prespa ◽  
Lake System ◽  
Deep Site

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.

scholarly journals Ecosystem regimes and responses in a coupled ancient lake system from MIS 5b to present: the diatom record of lakes Ohrid and Prespa

2015 ◽  
Vol 12 (17) ◽  
pp. 15051-15086 ◽  
Author(s):  
A. Cvetkoska ◽  
E. Jovanovska ◽  
A. Francke ◽  
S. Tofilovska ◽  
H. Vogel ◽  
...  
Keyword(s):  
High Capacity ◽  
Chemical Properties ◽  
Regime Shifts ◽  
Interglacial Period ◽  
Last Interglacial ◽  
Lake Ohrid ◽  
Lake Prespa ◽  
Lake System ◽  
Last Interglacial Period ◽  
Deep Site

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.

scholarly journals Sediment core fossils in ancient Lake Ohrid: testing for faunal change in molluscs since the Last Interglacial period

2010 ◽  
Vol 7 (3) ◽  
pp. 3969-3999 ◽  
Author(s):  
C. Albrecht ◽  
H. Vogel ◽  
T. Hauffe ◽  
T. Wilke
Keyword(s):  
Sediment Core ◽  
Fossil Record ◽  
Interglacial Period ◽  
Ancient Lake ◽  
Last Interglacial ◽  
Lake Ohrid ◽  
Last Interglacial Period ◽  
History Of ◽  
Extinction Events ◽  
Mollusc Shells

Abstract. Ancient Lake Ohrid is probably of early Pleistocene or Pliocene origin and amongst the few lakes in the world harboring an outstanding degree of endemic biodiversity. Although there is a long history of evolutionary research in Lake Ohrid, particularly on molluscs, a mollusc fossil record has been missing up to date. For the first time, gastropod and bivalve fossils are reported from the basal, calcareous part of a 2.6 m long sediment succession (core Co1200) from the north-eastern part of Lake Ohrid. Electron spin resonance (ESR) dating of mollusc shells from the same stratigraphic level yielded an age of 130±28 ka. Lithofacies III sediments, i.e. a subdivision of the stratigraphic unit comprising the basal succession of core Co1200 between 181.5–263 cm appeared solid, grayish-white, and consisted almost entirely of silt-sized endogenic calcite (CaCO3>70%) and intact and broken mollusc shells. Here we compare the faunal composition of the thanatocoenosis with recent mollusc associations in Lake Ohrid. A total of 13 mollusc species (9 gastropod and 4 bivalve species) could be identified within Lithofacies III sediments. The value of sediment core fossils for reconstructing palaeoenvironmental settings was evaluated. The agreement between sediment and palaeontological proxies was tested. The combined findings of the ecological study and the sediment characteristics suggest deposition in a shallow water environment during the Last Interglacial period. We tested for major faunal changes since the Last Interglacial period and searched for signs of extinction events. The fossil fauna exclusively included species also found in the present fauna, i.e. no extinction events are evident for this site since the Last Interglacial. The thanatocoenosis showed the highest similarity with recent Intermediate Layer (5–25 m) mollusc assemblages. The demonstrated existence of a mollusc fossil record in Lake Ohrid sediment cores also has great significance for future deep drilling projects. It can be hoped that a more far reaching mollusc fossil record will then be obtained, enabling insight into the early evolutionary history of Lake Ohrid.

Deposits and Soils of the Past 130,000 Years at the Desert–Loess Transition in Northern China

1998 ◽  
Vol 50 (2) ◽  
pp. 148-156 ◽  
Author(s):  
Jimin Sun ◽  
Zhongli Ding
Keyword(s):  
Northern China ◽  
Loess Soil ◽  
Transitional Zone ◽  
Central China ◽  
Interglacial Period ◽  
Glacial Cycle ◽  
Last Interglacial ◽  
Last Glacial Period ◽  
North Central ◽  
Last Interglacial Period

The desert–loess transitional zone in north-central China has long been thought sensitive to Quaternary climatic change. However, reconstruction of Quaternary climates in this area has been hindered by incompleteness of geological sections. Here we report the analytical results of two recently found sand–loess–soil sections. Both sections have thick eolian deposits from the last interglacial–glacial cycle and can be correlated with one another. Field observations, thermoluminescence dating, and other laboratory analyses show that the last interglacial period produced three paleosols and two intercalated loess layers. Loess from the last glacial period is interbedded with three sand horizons that represent desert extension. The expansion and contraction of desert in northern China may have been forced by the east Asia monsoon.

Reconciling reconstructions and simulations of the Greenland ice sheet and its climate during the Last Interglacial period

2020 ◽  
Author(s):  
Alexander Robinson ◽  
Emilie Capron ◽  
Jorge Alvarez-Solas ◽  
Michael Bender ◽  
Heiko Goelzer ◽  
...  
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ice Cores ◽  
Future Climate Change ◽  
Interglacial Period ◽  
Last Interglacial ◽  
Proxy Data ◽  
Last Interglacial Period

<p>There is still no consensus concerning the evolution of the Greenland ice sheet during the Last Interglacial period (LIG, 130-115 kyr ago). Ice cores indicate that the ice sheet survived over most of the continent. Proxy data indicate temperature anomalies of up to 6-8°C. However, under these conditions, models predict almost complete deglaciation. This paradox must be resolved to be able to quantify Greenland’s sea-level contribution during the LIG as well as to understand its sensitivity to future climate change. Here we analyze the available evidence and outline strategies to reconcile modeling and data efforts for Greenland during the LIG.</p>

scholarly journals Impact of Past and Future Climate Change on the Potential Distribution of an Endangered Montane Shrub Lonicera oblata and Its Conservation Implications

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 125
Author(s):  
Yuan-Mi Wu ◽  
Xue-Li Shen ◽  
Ling Tong ◽  
Feng-Wei Lei ◽  
Xian-Yun Mu ◽  
...  
Keyword(s):  
Climate Change ◽  
Endangered Species ◽  
Potential Distribution ◽  
North China ◽  
Distribution Area ◽  
Future Climate Change ◽  
Interglacial Period ◽  
Last Interglacial ◽  
Conservation Implications ◽  
Suitable Habitats

Climate change is an important driver of biodiversity patterns and species distributions, understanding how organisms respond to climate change will shed light on the conservation of endangered species. In this study, we modeled the distributional dynamics of a critically endangered montane shrub Lonicera oblata in response to climate change under different periods by building a comprehensive habitat suitability model considering the effects of soil and vegetation conditions. Our results indicated that the current suitable habitats for L. oblata are located scarcely in North China. Historical modeling indicated that L. oblata achieved its maximum potential distribution in the last interglacial period which covered southwest China, while its distribution area decreased for almost 50% during the last glacial maximum. It further contracted during the middle Holocene to a distribution resembling the current pattern. Future modeling showed that the suitable habitats of L. oblata contracted dramatically, and populations were fragmentedly distributed in these areas. As a whole, the distribution of L. oblata showed significant migration northward in latitude but no altitudinal shift. Several mountains in North China may provide future stable climatic areas for L. oblata, particularly, the intersections between the Taihang and Yan mountains. Our study strongly suggested that the endangered montane shrub L. oblata are sensitive to climate change, and the results provide new insights into the conservation of it and other endangered species.

scholarly journals Quaternary climate change and Heinrich events in the southern Balkans: Lake Prespa diatom palaeolimnology from the last interglacial to present

2014 ◽  
Vol 53 (2) ◽  
pp. 215-231 ◽  
Author(s):  
Aleksandra Cvetkoska ◽  
Zlatko Levkov ◽  
Jane M. Reed ◽  
Bernd Wagner ◽  
Konstantinos Panagiotopoulos ◽  
...  
Keyword(s):  
Climate Change ◽  
Last Interglacial ◽  
Heinrich Events ◽  
Lake Prespa ◽  
Quaternary Climate ◽  
Southern Balkans

Last glacial cycle hydrological change at Lake Tyrrell, southeast Australia

2006 ◽  
Vol 66 (1) ◽  
pp. 176-181 ◽  
Author(s):  
Tim Stone
Keyword(s):  
Interglacial Period ◽  
Silty Clay ◽  
Glacial Cycle ◽  
Last Interglacial ◽  
Southeast Australia ◽  
Last Interglacial Period ◽  
Lake Floor ◽  
Radiocarbon Chronology ◽  
High Pressure Zone ◽  
High Lake Levels

AbstractLake Tyrrell is the largest playa in the Murray Basin of southeast Australia. Optical dating of transverse dune (lunette) sediments extends the lake's radiocarbon chronology to the last interglacial period. The highest lake level was attained 131,000 ± 10,000 yr ago, forming Lake Chillingollah, a megalake that persisted until around 77,000 ± 4000 yr ago. Pedogenesis of its sandy lunette continued until buried by a silty clay lunette deflated from the lake floor 27,000 ± 2000 yr ago. The dated soil-stratigraphic units correlate with the upper Tyrrell Beds and contain evidence that humans visited the lakeshore before 27,000 yr ago. The Lake Chillingollah megalake was synchronous with very high lake levels in monsoon-dominated Australia, yet it was not influenced by tropical monsoon systems. It was filled instead by increased winter rainfall from westerly low-pressure fronts. Greater effective precipitation across Australia is evident, the result of a weakened subtropical high-pressure zone.

scholarly journals NGRIP CH<sub>4</sub> concentration from 120 to 10 kyr before present and its relation to a δ<sup>15</sup>N temperature reconstruction from the same ice core

2014 ◽  
Vol 10 (2) ◽  
pp. 903-920 ◽  
Author(s):  
M. Baumgartner ◽  
P. Kindler ◽  
O. Eicher ◽  
G. Floch ◽  
A. Schilt ◽  
...  
Keyword(s):  
Ice Core ◽  
High Ratio ◽  
Interglacial Period ◽  
Atmospheric Methane ◽  
Glacial Cycle ◽  
Last Interglacial ◽  
Concentration Difference ◽  
Temperature Variations ◽  
Last Glacial ◽  
The Last Glacial

Abstract. During the last glacial cycle, Greenland temperature showed many rapid temperature variations, the so-called Dansgaard–Oeschger (DO) events. The past atmospheric methane concentration closely followed these temperature variations, which implies that the warmings recorded in Greenland were probably hemispheric in extent. Here we substantially extend and complete the North Greenland Ice Core Project (NGRIP) methane record from the Preboreal Holocene (PB) back to the end of the last interglacial period with a mean time resolution of 54 yr. We relate the amplitudes of the methane increases associated with DO events to the amplitudes of the local Greenland NGRIP temperature increases derived from stable nitrogen isotope (δ15N) measurements, which have been performed along the same ice core (Kindler et al., 2014). We find the ratio to oscillate between 5 parts per billion (ppb) per °C and 18 ppb °C−1 with the approximate frequency of the precessional cycle. A remarkably high ratio of 25.5 ppb °C−1 is reached during the transition from the Younger Dryas (YD) to the PB. Analysis of the timing of the fast methane and temperature increases reveals significant lags of the methane increases relative to NGRIP temperature for DO events 5, 9, 10, 11, 13, 15, 19, and 20. These events generally have small methane increase rates and we hypothesize that the lag is caused by pronounced northward displacement of the source regions from stadial to interstadial. We further show that the relative interpolar concentration difference (rIPD) of methane is about 4.5% for the stadials between DO events 18 and 20, which is in the same order as in the stadials before and after DO event 2 around the Last Glacial Maximum. The rIPD of methane remains relatively stable throughout the full last glacial, with a tendency for elevated values during interstadial compared to stadial periods.

scholarly journals Predicting the dynamic distribution of Sphagnum bogs in China under climate change since the last interglacial period

PLoS ONE ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. e0230969
Author(s):  
Mingyang Cong ◽  
Yueyue Xu ◽  
Luyan Tang ◽  
Wenjing Yang ◽  
Minfei Jian
Keyword(s):  
Climate Change ◽  
Interglacial Period ◽  
Last Interglacial ◽  
Dynamic Distribution ◽  
Sphagnum Bogs ◽  
Last Interglacial Period
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