High-resolution environmental reconstruction in SW Peloponnese, Greece, covering the last c. 6000 years: Evidence from Agios Floros fen, Messenian plain

Abstract

A paleolimnological record from the central Messenian plain (southwestern Peloponnese, southern Greece) indicates rapid changes in the water level and chemistry of a transient lake on the flanks of the Taygetos Mountains during the last c. 6000 years. The analyses are based on diatoms as well as carbon and nitrogen isotopes from bulk sediments in a 7.5-m-long sediment core retrieved from the drained fen of Agios Floros, at the northern banks of the ancient River Pamisos. The sequence consists of fen peat in the uppermost section underlain by lacustrine sediments, which are punctuated by two layers of clay with diatomaceous silt bands. High accumulation rate is recorded in the oldest part of the section (up to 23 mm/yr), particularly during two decadal-long periods centered at c. 5700 and c. 5300 cal. BP. The diatom record reveals pronounced peaks in the planktonic taxon Cyclotella distinguenda, which correspond to the laminated sequences, reflecting the rapid development of a deep lake with an open water environment during these two time periods. Another two events with intermediate water levels are inferred at c. 5200 and c. 4600 cal. BP. These short-lived phases were probably, to a large extent, caused by local tectonic processes and the consequent hydrological anomalies of the nearby karst springs, although abrupt climatic changes with enhanced precipitation might have also played a role. At c. 4500 cal. BP, our data suggest the development of terrestrial conditions in this area, which can be attributed to the decreasing activity/dry up of springs, probably associated with more arid climate. After c. 2500 cal. BP, the diatom record infers a return to wetter conditions, probably as a response to more humid climate with marked seasonality and human activities, developing the present-day environment with cultivated and seasonally semi-flooded fields.

Holocene variability in climate and oceanic conditions in the winter rainfall zone of South Africa—inferred from a high resolution diatom record from Verlorenvlei

“…Greater freshwater penetration is recorded between 8000 and 7500 cal a bp , as fresh and brackish water taxa such as Cyclotella distinguenda and Achnanthes oblongella increase. The latter species is characteristic of oligotrophic, electrolyte‐poor streams (Taylor et al , 2007), while the former are typically recorded in deep, well‐stratified freshwaters extending into estuarine habitats (Katrantsiotis et al , 2015). A highly variable TOC/TN ratio between 8000 and 7000 cal a bp suggests fluctuations between aquatic (values around 10) and terrestrial (values > 15) organic component sources (Fig.…”

Late Bronze Age climate change and the destruction of the Mycenaean Palace of Nestor at Pylos

“…The δ 18 O and δ 13 C results from Mavri Trypa indicate relatively wet conditions from 4700 yrs BP to 4500 yrs BP, followed by a transitional period with large isotopic fluctuations from 4500 yrs BP to 4300 yrs BP leading towards drier conditions ( Fig 4 ; S2 Fig ). A diatom record from the nearby Agios Floros wetland also shows a development of aridity from 4500 yrs BP [ 86 ]. Stable arid conditions in Mavri Trypa occur from 4300 yrs BP until stalagmite S1 stops growing at 4200 yrs BP.…”

“…The overall enrichment in the δ 18 O values that occurred during the first 200 years of this period likely results from these samples being milled towards the flank of the stalagmite in this section and is not related to climate ( S2 Fig ). Other paleoclimate records from the Peloponnese indicate wetter conditions from ~2550 yrs BP [ 45 , 64 , 86 , 87 ]. It is possible that the duration of the second hiatus in the Mavri Trypa stalagmite is not only a result of drier conditions, but also relates to the rerouting of water through the bedrock or human intervention in or near the cave.…”

Biomarker hydrogen isotope composition (δD) as proxy for Holocene hydroclimatic change and seismic activity in SW Peloponnese, Greece

“…This study is the first attempt to contribute water isotope data from a terrestrial archive from southern mainland Greece (the Peloponnese) using biomarkers. As such, our study has a two‐fold approach: (i) to validate the δD biomarker application for this particular environmental and geographical setting by comparing the outcome with previous indications of hydroclimate and paleoseismicity based on diatom and sedimentological data (Katrantsiotis et al ., ,b), and (ii) to establish a continuous, regional hydroclimate record for the last 6000 years and place it within the context of regional paleoclimatological signals inferred by other proxy records from the Peloponnese and the wider eastern Mediterranean region.…”

“…The Holocene climate and environment of the Peloponnese has been studied with increased interest in recent years, and several new sites have produced valuable climate reconstructions (e.g. Heymann et al ., ; Finné et al ., ; Unkel et al ., ; Boyd, ; Katrantsiotis et al ., ,b; Finné et al ., ; Norström et al ., ). A high‐resolution diatom record from Agios Floros fen, near the city of Kalamata (Katrantsiotis et al ., ), indicates that this area constitutes an important geoarchive with constant sediment deposition and rapid water level shifts during the last c .…”