scholarly journals Holocene vegetation and climate changes in the central Mediterranean inferred from a high-resolution marine pollen record (Adriatic Sea)

2013 ◽  
Vol 9 (5) ◽  
pp. 2023-2042 ◽  
Author(s):  
N. Combourieu-Nebout ◽  
O. Peyron ◽  
V. Bout-Roumazeilles ◽  
S. Goring ◽  
I. Dormoy ◽  
...  
Keyword(s):  
High Resolution ◽  
Clay Mineral ◽  
Climate Changes ◽  
Adriatic Sea ◽  
General Pattern ◽  
Summer Precipitation ◽  
Pollen Record ◽  
Seasonal Precipitation ◽  
Central Mediterranean ◽  
The Holocene

Abstract. The high-resolution multiproxy study of the Adriatic marine core MD 90-917 provides new insights to reconstruct vegetation and regional climate changes over the southcentral Mediterranean during the Younger Dryas (YD) and Holocene. Pollen records show the rapid forest colonization of the Italian and Balkan borderlands and the gradual installation of the Mediterranean association during the Holocene. Quantitative estimates based on pollen data provide Holocene precipitations and temperatures in the Adriatic Sea using a multi-method approach. Clay mineral ratios from the same core reflect the relative contributions of riverine (illite and smectite) and eolian (kaolinite) contributions to the site, and thus act as an additional proxy with which to evaluate precipitation changes in the Holocene. Vegetation climate reconstructions show the response to the Preboreal oscillation (PBO), most likely driven by changes in temperature and seasonal precipitation, which is linked to increasing river inputs from Adriatic rivers recorded by increase in clay mineral contribution to marine sediments. Pollen-inferred temperature declines during the early–mid Holocene, then increases during the mid–late Holocene, similar to southwestern Mediterranean climatic patterns during the Holocene. Several short vegetation and climatic events appear in the record, indicating the sensitivity of vegetation in the region to millennial-scale variability. Reconstructed summer precipitation shows a regional maximum (170–200 mm) between 8000 and 7000 similar to the general pattern across southern Europe. Two important shifts in vegetation occur at 7700 cal yr BP (calendar years before present) and between 7500 and 7000 cal yr BP and are correlated with increased river inputs around the Adriatic Basin respectively from the northern (7700 event) and from the central Adriatic borderlands (7500–7000 event). During the mid-Holocene, the wet summers lead to permanent moisture all year resulting in a homogeneous seasonal precipitation regime. After 6000 cal yr BP, summer precipitation decreases towards present-day values while winter precipitation rises regularly showing the setting up of Mediterranean climate conditions. Multiproxy evidence from core MD 90-917 provides a deeper understanding of the role of precipitation and particularly the seasonality of precipitation in mediating vegetation change in the central Mediterranean during the Holocene.

scholarly journals Holocene vegetation and climate changes in central Mediterranean inferred from a high-resolution marine pollen record (Adriatic Sea)

2013 ◽  
Vol 9 (2) ◽  
pp. 1969-2014 ◽  
Author(s):  
N. Combourieu-Nebout ◽  
O. Peyron ◽  
V. Bout-Roumazeilles ◽  
S. Goring ◽  
I. Dormoy ◽  
...  
Keyword(s):  
Climate Changes ◽  
Climatic Variability ◽  
General Pattern ◽  
Future Climate Change ◽  
Pollen Record ◽  
Seasonal Precipitation ◽  
Central Mediterranean ◽  
The Holocene ◽  
Vegetation Shifts ◽  
South Central

Abstract. To understand the effects of future climate change on the ecology of the central Mediterranean we can look to the impacts of long-term, millennial to centennial-scale climatic variability on vegetation in the basin. Pollen data from the Adriatic Marine core MD 90-917 allows us to reconstruct vegetation and regional climate changes over the south central Mediterranean during the Holocene. Clay mineral ratios from the same core reflect the relative contributions of riverine (illite and smectite) and eolian (kaolinite) contributions to the site, and thus act as an additional proxy with which to test precipitation changes in the Holocene. Vegetation reconstruction shows vegetation responses to the late-Glacial Preboreal oscillation, most likely driven by changes in seasonal precipitation. Pollen-inferred temperature declines during the early-mid Holocene, but increases during the mid-late Holocene, similar to southern-western Mediterranean climatic patterns during the Holocene. Several short climatic events appear in the record, indicating the sensitivity of vegetation in the region to millennial-scale variability. Reconstructed summer precipitation shows a regional maximum between 8000 and 7000 cal yr BP similar to the general pattern across southern Europe. Two important shifts in vegetation occur at 7700 and between 7500 and 7000 yr. These vegetation shifts are linked to changes in seasonal precipitation and are correlated to increased river inputs respectively from the north (7700 event) and from the central Adriatic borderlands (7500–7000 event). These results reinforce the strengths of multi-proxy analysis and provide a deeper understanding of the role of precipitation and particularly the seasonality of precipitation in mediating vegetation change in the central Mediterranean during the Holocene.

scholarly journals Rapid climatic variability in the west Mediterranean during the last 25 000 years from high resolution pollen data

2009 ◽  
Vol 5 (3) ◽  
pp. 503-521 ◽  
Author(s):  
N. Combourieu Nebout ◽  
O. Peyron ◽  
I. Dormoy ◽  
S. Desprat ◽  
C. Beaudouin ◽  
...  
Keyword(s):  
High Resolution ◽  
North Atlantic ◽  
Climate Reconstruction ◽  
Mediterranean Vegetation ◽  
Pollen Record ◽  
Alboran Sea ◽  
Climatic Fluctuations ◽  
The Holocene ◽  
The Mediterranean ◽  
Alborán Sea

Abstract. High-temporal resolution pollen record from the Alboran Sea ODP Site 976, pollen-based quantitative climate reconstruction and biomisation show that changes of Mediterranean vegetation have been clearly modulated by short and long term variability during the last 25 000 years. The reliability of the quantitative climate reconstruction from marine pollen spectra has been tested using 22 marine core-top samples from the Mediterranean. The ODP Site 976 pollen record and climatic reconstruction confirm that Mediterranean environments have a rapid response to the climatic fluctuations during the last Termination. The western Mediterranean vegetation response appears nearly synchronous with North Atlantic variability during the last deglaciation as well as during the Holocene. High-resolution analyses of the ODP Site 976 pollen record show a cooling trend during the Bölling/Allerød period. In addition, this period is marked by two warm episodes bracketing a cooling event that represent the Bölling-Older Dryas-Allerød succession. During the Holocene, recurrent declines of the forest cover over the Alboran Sea borderlands indicate climate events that correlate well with several events of increased Mediterranean dryness observed on the continent and with Mediterranean Sea cooling episodes detected by alkenone-based sea surface temperature reconstructions. These events clearly reflect the response of the Mediterranean vegetation to the North Atlantic Holocene cold events.

scholarly journals Holocene Asian monsoon evolution revealed by a pollen record from an alpine lake on the southeastern margin of the Qinghai–Tibetan Plateau, China

2016 ◽  
Vol 12 (2) ◽  
pp. 415-427 ◽  
Author(s):  
Enlou Zhang ◽  
Yongbo Wang ◽  
Weiwei Sun ◽  
Ji Shen
Keyword(s):  
Late Holocene ◽  
Southern Oscillation ◽  
Summer Precipitation ◽  
Forest Understory ◽  
Pollen Record ◽  
The Holocene ◽  
Asian Winter Monsoon ◽  
Holocene Climatic Optimum ◽  
Southeastern Margin ◽  
Climatic Optimum

Abstract. We present the results of pollen analyses from a 1105 cm long sediment core from Wuxu Lake in southwestern China, which depict the variations of the East Asian winter monsoon (EAWM) and the Indian summer monsoon (ISM) during the last 12.3 ka. During the period of 12.3 to 11.3 cal ka BP, the dominance of Betula forest and open alpine shrub and meadow around Wuxu Lake indicates a climate with relatively cold winters and dry summers, corresponding to the Younger Dryas event. Between 11.3 and 10.4 cal ka BP, further expansion of Betula forest and the retreat of alpine shrubs and meadows reflect a greater seasonality with cold winters and gradually increasing summer precipitation. From 10.4 to 4.9 cal ka BP, the dense forest understory, together with the gradual decrease in Betula forest and increase in Tsuga forest, suggest that the winters became warmer and summer precipitation was at a maximum, corresponding to the Holocene climatic optimum. Between 4.9 and 2.6 cal ka BP, Tsuga forest and alpine shrubs and meadows expanded significantly, reflecting relatively warm winters and decreased summer precipitation. Since 2.6 cal ka BP, reforestation around Wuxu Lake indicates a renewed humid period in the late Holocene; however, the vegetation in the catchment may also have been affected by grazing activity during this period. The results of our study are generally consistent with previous findings; however, the timing and duration of the Holocene climatic optimum from different records are inconsistent, reflecting real contrast in local rainfall response to the ISM. Overall, the EAWM is broadly in-phase with the ISM on the orbital timescale, and both monsoons exhibit a trend of decreasing strength from the early to late Holocene, reflecting the interplay of solar insolation receipt between the winter and summer seasons and El Niño–Southern Oscillation strength in the tropical Pacific.

scholarly journals Holocene Asian monsoon evolution revealed by a pollen record from an alpine lake on the southeastern margin of the Qinghai-Tibetan Plateau, China

2015 ◽  
Vol 11 (5) ◽  
pp. 4751-4786
Author(s):  
E. Zhang ◽  
Y. Wang ◽  
W. Sun ◽  
J. Shen
Keyword(s):  
Late Holocene ◽  
Southern Oscillation ◽  
Summer Precipitation ◽  
Forest Understory ◽  
Pollen Record ◽  
The Holocene ◽  
Asian Winter Monsoon ◽  
Holocene Climatic Optimum ◽  
Southeastern Margin ◽  
Climatic Optimum

Abstract. We present the results of pollen analyses from a 1105-cm-long sediment core from Wuxu Lake in southwestern China, which depict the variations of the East Asian winter monsoon (EAWM) and the Indian summer monsoon (ISM) during the last 12.3 ka. During the period of 12.3 to 11.3 cal ka BP, the dominance of Betula forest and open alpine shrub and meadow around Wuxu Lake indicates a climate with relatively cold winters and dry summers, corresponding to the Younger Dryas event. Between 11.3 and 10.4 cal ka BP, further expansion of Betula forest and the retreat of alpine shrubs and meadows reflect a greater seasonality with cold winters and gradually increasing summer precipitation. From 10.4 to 4.9 cal ka BP, the dense forest understory, together with the gradual decrease in Betula forest and increase in Tsuga forest, suggest that the winters became warmer and summer precipitation was at a maximum, corresponding to the Holocene climatic optimum. Between 4.9 and 2.6 cal ka BP, Tsuga forest and alpine shrubs and meadows expanded significantly, reflecting relatively warm winters and decreased summer precipitation. Since 2.6 cal ka BP, reforestation around Wuxu Lake indicates a renewed strengthening of the ISM in the late Holocene; however, the vegetation in the catchment may also have been affected by grazing activity during this period. The results of our study are generally consistent with previous findings; however, the timing and duration of the Holocene climatic optimum from different records are inconsistent, reflecting real contrast in local rainfall response to the ISM. Overall, the EAWM is broadly in-phase with the ISM on the orbital timescale, and both monsoons exhibit a trend of decreasing strength from the early to late Holocene, reflecting the interplay of solar insolation receipt between the winter and summer seasons and El Niño Southern Oscillation strength in the tropical Pacific.

Vegetation and climate changes during the last 8660 cal. a BP in central Mongolia, based on a high-resolution pollen record from Lake Ugii Nuur

2009 ◽  
Vol 54 (9) ◽  
pp. 1579-1589 ◽  
Author(s):  
Wei Wang ◽  
YuZhen Ma ◽  
ZhaoDong Feng ◽  
HongWei Meng ◽  
YanLi Sang ◽  
...  
Keyword(s):  
High Resolution ◽  
Climate Changes ◽  
Pollen Record ◽  
Central Mongolia ◽  
Vegetation And Climate

scholarly journals Contrasting patterns of climatic changes during the Holocene in the Central Mediterranean (Italy) reconstructed from pollen data

2012 ◽  
Vol 8 (6) ◽  
pp. 5817-5866 ◽  
Author(s):  
O. Peyron ◽  
M. Magny ◽  
S. Goring ◽  
S. Joannin ◽  
J.-L. de Beaulieu ◽  
...  
Keyword(s):  
Lake Level ◽  
Late Holocene ◽  
Summer Precipitation ◽  
Aegean Sea ◽  
Weighted Averaging ◽  
Lake Levels ◽  
Central Mediterranean ◽  
The Holocene ◽  
The North ◽  
The Mediterranean

Abstract. Lake-level records from Italy suggest a north–south climatic partition in the Central Mediterranean during the Holocene with respect to precipitation, but the scarcity of reliable palaeoclimatic records in the North and Central-Southern Mediterranean means new evidence is needed to validate this hypothesis. Here, we provide robust quantitative estimates of Holocene climate in the Mediterranean region based on four high-resolution pollen records from Northern (Lakes Ledro and Accesa) and Southern (Lakes Trifoglietti and Pergusa) Italy. Multiple methods are used to provide an improved assessment of the paleoclimatic reconstruction uncertainty. The multi-method approach uses the pollen-based Weighted Averaging, Weighted-Average-Partial-Least-Squares regression, Modern Analogues Technique, and the Non-Metric-Multidimensional Scaling/Generalized-Additive-Model methods. The precipitation seasonality reconstructions are validated by independent lake-level data, obtained from the same records. A climatic partition between the north and the south during the Holocene confirms the hypothesis of opposing mid-Holocene summer precipitation regimes in the Mediterranean. During the early-to-mid-Holocene the northern sites (Ledro, Accesa) are characterized by minima for summer precipitation and lake-levels while the southern sites (Trifoglietti, Pergusa) are marked by maxima for precipitation and lake-levels. During the late Holocene, both pollen-inferred precipitation and lake-levels indicate the opposite pattern, a maximum in North Italy and a minimum in Southern Italy/Sicily. Summer temperatures also show partitioning, with warm conditions in Northern Italy and cool conditions in Sicily during the early/mid-Holocene, and a reversal during the Late-Holocene. Comparison with marine cores from the Aegean Sea suggests that climate trends and gradients observed in Italy shows strong similarities with those recognized from the Aegean Sea, and more generally speaking in the Eastern Mediterranean.

The influence of seasonal precipitation and temperature regimes on lake levels in the northeastern United States during the Holocene

2006 ◽  
Vol 65 (1) ◽  
pp. 44-56 ◽  
Author(s):  
Bryan Shuman ◽  
Jeffrey P. Donnelly
Keyword(s):  
Sediment Cores ◽  
Summer Precipitation ◽  
Water Levels ◽  
Monthly Precipitation ◽  
Seasonal Precipitation ◽  
Lake Levels ◽  
Precipitation Regime ◽  
The Holocene ◽  
Temperature Regimes ◽  
Precipitation Regimes

AbstractAMS–dated sediment cores combined with ground–penetrating radar profiles from two lakes in southeastern Massachusetts demonstrate that regional water levels rose and fell multiple times during the Holocene when the known climatic controls (i.e., ice extent and insolation) underwent unidirectional changes. The lakes were lowest between 10,000 and 9000 and between 5500 and 3000 cal yr B.P. Using a heuristic moisture-budget model, we explore the hypothesis that changes in seasonal precipitation regimes, driven by monotonic trends in ice extent and insolation, plausibly explain the multiple lake-level changes. Simulated lake levels resulting from low summer precipitation rates match observed low lake levels of 10,000–9000 cal yr B.P., whereas a model experiment that simply shifts the seasonality of the modern Massachusetts precipitation regime (i.e., moving the peak monthly precipitation from winter to summer) produces levels that are ∼2 m lower than today as observed for 5500–3000 cal yr B.P. The influence of the Laurentide ice sheet could explain dry summers before ca. 8000 cal yr B.P. A later shift from a summer-wet to a winter-wet moisture-balance regime could have resulted from insolation-driven changes in the influence of the Bermuda subtropical high. Temperature changes probably further modified lake levels by affecting snowmelt and transpiration.

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