Palinologia de turfas do alto curso do Arroio Cará, Coxilha Rica, Santa Catarina, Brasil

Palynology of peaty sediments from the high course of Cará Brook Creek, Coxilha Rica, Santa Catarina, Brazil. This paper presents the results of the palynological study of a sedimentary core collected in a bog in the upper part valley of Cará Brook Creek, in the cultural territory of Coxilha Rica, located in the Campos Gerais Plateau in Santa Catarina, Southern Brazil. The base of the core was dated in 6.900 14C years BP (7,845–7,690 cal years BP). The identification of the palynomorphs and the cluster analysis made possible to define two distinct palynological phases, despite the predominance of grassland vegetation throughout the whole core. From 34 cm, the frequency of bryophytes decreases, accompanied by the increase of the diversity of all vegetal taxa. Throughout the core, the most frequent families are Poaceae, Cyperaceae Apiaceae. The results indicate that the landscape of the upper course of the Brook Creek was characterized by grasslands from 6,900 14C years BP under a regional and humid climate, with a temperature increase in the historical period. Keywords: Middle Holocene, palynomorphs, grasslands, Araucaria forest, Highland.

Identification of New Sub-Fossil Diatoms Flora in the Sediments of Suncheonman Bay, Korea

Suncheonman Bay, Korea’s most representative estuary, is an invasive coastal wetland composed of 22.6 km2 of tidal flats surrounded by the Yeosu and Goheung Peninsulas. In January 2006, this region was registered in the Ramsar Convention list in Korea, representing the first registered wetland. Estuaries are generally known to have high species diversity. In particular, several studies have been conducted on planktonic and epipelic diatoms as primary producers. Suncheonman Bay has already been involved in many biological and geochemical studies, but fossil diatoms have not been evaluated. Therefore, we investigated fossil diatoms in Suncheonman Bay and introduced sub-fossil diatoms recorded in Korea. One sedimentary core has been extracted in 2018. We identified 87 diatom taxa from 52 genera in the SCW03 core sample. Of these, six species represent new records in Korea: Cymatonitzschia marina, Fallacia hodgeana, Navicula mannii, Metascolioneis tumida, Surirella recedens, and Thalassionema synedriforme. These six newly recorded diatom species were examined by light microscopy and scanning electron microscopy. The ecological habitats for all the investigated taxa are presented.

Continuous presence of proto-cereals in Anatolia since 2.3 Ma, and their possible co-evolution with large herbivores and hominins

Cereals are a central resource for the human diet and are traditionally assumed to have evolved from wild grasses at the onset of the Neolithic under the pressure of agriculture. Here we demonstrate that cereals may have a significantly longer and more diverse lineage, based on the study of a 0–2.3 Ma, 601 m long sedimentary core from Lake Acıgöl (South-West Anatolia). Pollen characteristic of cereals is abundant throughout the sedimentary sequence. The presence of large lakes within this arid bioclimatic zone led to the concentration of large herbivore herds, as indicated by the continuous occurrence of coprophilous fungi spores in the record. Our hypothesis is that the effects of overgrazing on soils and herbaceous stratum, during this long period, led to genetic modifications of the Poaceae taxa and to the appearance of proto-cereals. The simultaneous presence of hominins is attested as early as about 1.4 Ma in the lake vicinity, and 1.8 Ma in Georgia and Levant. These ancient hominins probably benefited from the availability of these proto-cereals, rich in nutrients, as well as various other edible plants, opening the way, in this region of the Middle East, to a process of domestication, which reached its full development during the Neolithic.

Using sedaDNA to reconstruct planktonic communities across 385’000 years old marine sedimentary core from a tropical sea.

<p>Sedimentary ancient DNA (sedaDNA) is becoming a paleo-proxy of choice for many marine environments. However, there are few studies from tropical sites and even fewer from tropical marine sediments exposed to factors damaging the DNA such as elevated sea surface water temperature or UV radiation. Here, we report successful extraction of DNA from a marine sedimentary core retrieved from the Bismarck Sea, off New Papua Guinea, where the mean annual temperature is about 29°C. The core MD05-2920 covers the last 385 000 years. We analyzed samples from 20 layers, where the isotopic measures of δ<sup>18</sup>O isotopic composition of benthic foraminifera show significant palaeoceanographic changes from glacial to interglacial periods. We apply a metabarcoding approach using specific 18S primers for planktonic foraminifera, diatoms, and radiolarians. Even if the amount of DNA declines throughout the core, the patterns of successional changes in species communities of these three taxonomic groups are well archived. Our study shows that it is possible to reconstruct the planktonic community even from very old sedaDNA samples from a tropical marine sedimentary core.</p>

A new reference loess-paleosol archive spanning the last 850 kyrs near Pleven (Bulgaria) – first results

<p>Loess-paleosol sequences (LPSs) are proven valuable archives for continental paleoclimatic reconstructions. However, studied LPSs worldwide, spanning multiple glacial-interglacial cycles, are seldomly sampled and analyzed at a continuous high resolution. Exceptionally, in a quarry setting near the city of Pleven (Bulgaria), a new LPS, with a thickness of 27 m, was continuously sampled at a 2 cm resolution resulting in 1340 bulk-samples. We present herein first rock magnetic results suggesting that the site archives aeolian deposition and soil formation over the last 850 kyrs.  Room temperature bulk mineral magnetic parameters including magnetic susceptibility, hysteresis loop derived parameters, IRM, and ARM (underway) were acquired on all samples. Variations in mineral magnetic data clearly show the alternation of strongly developed paleosols overlying loess units indicative of interglacial and glacial climate cycles. We created a correlative age model by comparing X<sub>ferri</sub>/M<sub>s</sub> to inverted LR04 benthic oxygen isotope ratios and adjustments undertaken by the Imbrie & Imbrie ice model. This initial correlative age model leads to an assumed continuous dust accumulation for the last 850 kyrs, from MIS 19 to present. In addition to the regionally widely observed L2-tephra, which is observed outcropping along the Pleven LPS, several other sharp spikes in concentration dependent magnetic characteristics suggest that the sedimentary record had preserved also other tephra layers, clearly identified in the magnetic record due to the accomplished high-resolution sampling design. Additional geochemical and mineralogical data are however necessary for an unequivocal source (age) identification of these events. A tentative scheme of a possible correspondence with well dated tephra layers from sedimentary core at Fucino Basin is established. It implies the occurrence of westerly wind directions during the last 850 kyrs in SE Europe. In summary, the Pleven LPS provides new insights into late-Pleistocene climatic regimes, prevailing wind directions and preservation of tephra layers, essential for further correlative terrestrial-aeolian-coupled age models, regional stratigraphic correlations and paleoclimate reconstructions.</p>