Patterns in recent and Holocene pollen accumulation rates across Europe - the Pollen Monitoring Programme Database as a tool for vegetation reconstruction

The collection of modern, spatially extensive pollen data is important for the interpretation of fossil pollen assemblages and the reconstruction of past vegetation communities in space and time. Modern datasets are readily available for percentage data but lacking for pollen accumulation rates (PARs). Filling this gap has been the motivation of the pollen monitoring network, whose contributors monitored pollen deposition in modified Tauber traps for several years or decades across Europe. Here we present this monitoring dataset consisting of 351 trap locations with a total of 2742 annual samples covering the period from 1981 to 2017. This dataset shows that total PAR is influenced by forest cover and climate parameters, which determine pollen productivity and correlate with latitude. Treeless vegetation produced PAR values of at least 140 grains cm−2 yr−1. Tree PAR increased by at least 400 grains cm−2 yr−1 with each 10 % increase in forest cover. Pollen traps situated beyond 200 km of the distribution of a given tree species still collect occasional pollen grains of that species. The threshold of this long-distance transport differs for individual species and is generally below 60 grains cm−2 yr−1. Comparisons between modern and fossil PAR from the same regions show similar values. For temperate taxa, modern analogues for fossil PARs are generally found downslope or southward of the fossil sites. While we do not find modern situations comparable to fossil PAR values of some taxa (e.g. Corylus), CO2 fertilization and land use may cause high modern PARs that are not documented in the fossil record. The modern data are now publicly available in the Neotoma Paleoecology Database and aid interpretations of fossil PAR data.publishedVersio

Patterns in recent and Holocene pollen accumulation rates across Europe - the Pollen Monitoring Programme Database as a tool for vegetation reconstruction

The collection of modern, spatially extensive pollen data is important for the interpretation of fossil pollen assemblages and the reconstruction of past vegetation communities in space and time. Modern datasets are readily available for percentage data but lacking for pollen accumulation rates (PARs). Filling this gap has been the motivation of the pollen monitoring network, whose contributors monitored pollen deposition in modified Tauber traps for several years or decades across Europe. Here we present this monitoring dataset consisting of 351 trap locations with a total of 2742 annual samples covering the period from 1981 to 2017. This dataset shows that total PAR is influenced by forest cover and climate parameters, which determine pollen productivity and correlate with latitude. Treeless vegetation produced PAR values of at least 140 grains cm(-2) yr(-1). Tree PAR increased by at least 400 grains cm(-2) yr(-1) with each 10% increase in forest cover. Pollen traps situated beyond 200 km of the distribution of a given tree species still collect occasional pollen grains of that species. The threshold of this long-distance transport differs for individual species and is generally below 60 grains cm(-2) yr(-1). Comparisons between modern and fossil PAR from the same regions show similar values. For temperate taxa, modern analogues for fossil PARs are generally found downslope or southward of the fossil sites. While we do not find modern situations comparable to fossil PAR values of some taxa (e.g. Corylus), CO2 fertilization and land use may cause high modern PARs that are not documented in the fossil record. The modern data are now publicly available in the Neotoma Paleoecology Database and aid interpretations of fossil PAR data

Forest vegetation history of Troodos mountain, Cyprus

Palynological research was carried out at two peat cores extracted from the peat grasslands of “Almyrolivado” and “Pasa Livadi” (Troodos Mt., Cyprus), both located at altitudes of 1600 m approximately, within the Pinus nigra ssp. pallasiana zone.. In addition, modern pollen monitoring was carried out in relation to surrounding vegetation by means of four pollen traps based on the guidelines of the Pollen Monitoring Programme. Four pollen traps were placed at total; one per peat grassland, and two at clearings of Pinus brutia forest. Data vary from six to nine years. The peat cores consist predominantly of peat, silt and clay. The sampling intervals used in the two cores for the needs of pollen analysis, were 2 cm in Almyrolivado and 5 cm in Pasa Livadi. Samples of 1 cm3 were processed and mounted using standard preparation protocol. At least 300 pollen grains of arboreal pollen were counted per sample. Pollen diagrams constructed represent percentages and concentration values. Zonation of the diagrams was obtained using CONISS (Grimm 1987). The chronological pattern of the cores is provided by six AMS 14C datings, three for each core. The chronological sequence from “Almyrolivado” starts at 8433 cal yr BP, where as the “Pasa Livadi” starts at 3397 cal yr BP. Modern pollen monitoring that was conducted in the study area, revealed that the dominant arboreal pollen type was the Pinus sylvestris type, thus verifying the fact that the traps are located near or within pine forests. Other significant AP types identified include the Quercus ilex type, Juniperus, Cistus albidus type and Cistus salviifolius. The higher values of Quercus ilex type were recorded in Tr4, reflecting its substantial participation in the surrounding vegetation of the area. Cistus salviifolius was present only in the pollen traps located at the Pinus brutia zone, thus verifying its participation in these forest habitats. On the contrary, it was noted that this particular type was absent from the recordings of the two traps of the peat grasslands. Thus, this particular pollen type can serve as a classification index between the two pine forest habitats. The pollen diagrams from the peat cores revealed that the dominating arboreal species for both cores are pine and juniper, while the presence of oak is fluctuating through time. The pollen spectrum revealed fluctuations in the climate, that match similar others in the region of Eastern Mediterranean. Overall, the prevailing climatic conditions of the study area during the Mid-Holocene do not differentiate substantially from the current. The floristic composition of the peat grasslands communities varies depending on the ecological conditions, and is apparently affected by the influx of water, as well as the rate and the duration of the flooding. High values of pollen types from arboreal species coupled with the lack of anthropogenic pollen indicators, indicate that vegetation at higher altitudes remained essentially unaltered in terms of species composition, except during the Bronze Age. Charcoal particles present in both pollen diagrams throughout the whole chronological sequences, thus indicating the occurrence of fire events from time to time.Για τη διερεύνηση της ιστορικής εξέλιξης της δασικής βλάστησης του όρους Τρόοδος πραγματοποιήθηκε παλυνολογική έρευνα σε δύο προφίλ ιζήματος από τους τυρφώνες «Αλμυρολίβαδο» και «Πασά Λιβάδι», που βρίσκονται στην οροσειρά του Τροόδους στην Κύπρο, σε υψόμετρο από 1586 έως 1605 m. Παράλληλα, πραγματοποιήθηκε καταγραφή της γυρεοχλωρίδας της περιοχής έρευνας, μέσω «ειδικών παγίδων γύρης». Στις θέσεις λήψης των δύο προφίλ εντός της ζώνης εξάπλωσης της μαύρης πεύκης, τοποθετήθηκαν οι δύο από τις τέσσερεις παγίδες γύρης και σε διάκενα στη ζώνη εξάπλωσης της τραχείας πεύκης οι άλλες δύο. Τα προφίλ αποτελούνται από τύρφη, ιλύ και άργιλο. Συνολικά, πραγματοποιήθηκαν έξι χρονολογήσεις με τη μέθοδο του ραδιενεργού άνθρακα 14C. Το προφίλ Αλμυρολίβαδο έχει ηλικία 8433 έτη και το προφίλ Πασά Λιβάδι 3347 έτη. Από τα προφίλ εξήχθησαν και αναλύθηκαν 92 δείγματα ανά 2 cm για το Αλμυρολίβαδο, και 35 δείγματα ανά 5 cm για το Πασά Λιβάδι. Ακολούθως αφού μικροσκοπήθηκαν, αναγνωρίστηκαν και καταγράφηκαν οι γυρεόκοκκοι κάθε δείγματος μέχρι να συμπληρωθεί αριθμός τουλάχιστον 300 γυρεοκόκκων ξυλωδών taxa. Τα αποτελέσματα απεικονίζονται σε διαγράμματα ποσοστιαίων τιμών γύρης και τιμών συγκέντρωσης γύρης. Η επεξεργασία του υλικού και των αποτελεσμάτων των δεδομένων, από τις παγίδες γύρης έγινε σύμφωνα με τις μεθοδολογικές προδιαγραφές του Pollen Monitoring Programme. Η καταγραφή της γυρεοχλωρίδας μέσω των παγίδων γύρης, έδειξε ότι μεταξύ των γυρεοκόκκων ξυλωδών ειδών κυριαρχεί ο Pinus sylvestris type, και αντικατοπτρίζει το γεγονός ότι όλες οι παγίδες είναι τοποθετημένες κοντά ή μέσα σε πευκοδάση. Άλλοι σημαντικοί τύποι γύρης είναι οι Quercus ilex type, Juniperus, Cistus albidus type και Cistus salviifolius type. Οι μεγαλύτερες τιμές Quercus ilex type καταγράφηκαν στην παγίδα Tr4 και αντικατοπτρίζουν την αυξημένη συμμετοχή του στην περιβάλλουσα βλάστηση. Ο τύπος γύρης Cistus salviifolius καταγράφηκε μόνο στις παγίδες της ζώνης εξάπλωσης της τραχείας πεύκης και όχι στις παγίδες των τυρφώνων. Ο συγκεκριμένος τύπος γύρης αποτελεί δείκτη διάκρισης για τους οικοτόπους τραχείας και μαύρης πεύκης. Από τα αποτελέσματα της έρευνας για την εξέλιξη της βλάστησης προέκυψε ότι η δασική βλάστηση διαχρονικά κυριαρχείται από φυσικό πευκοδάσος, στοιχείο που οδηγεί στο συμπέρασμα ότι οι κλιματικές συνθήκες που επικρατούσαν στο νησί από την 7η χιλιετία π. Χ. και εφεξής, σε γενικές γραμμές, παραμένουν σταθερές. Εντοπίστηκαν διακυμάνσεις κλιματικών αλλαγών, που συμπίπτουν χρονολογικά με ανάλογες στην ευρύτερη ανατολική Μεσόγειο μέσω διαφοροποίησης της βλάστησης. Αυτή διακρίνεται μέσω εναλλαγών στις τιμές της πεύκης και της αρκεύθου, που οφείλονται στις αλλαγές της πυκνότητας του δάσους. Εναλλαγές των τιμών υγρόφιλων ειδών υποδεικνύουν ξηρές περιόδους. Οι υψηλές τιμές ξυλωδών ειδών, σε συνδυασμό με την απουσία τύπων γύρης «δεικτών» γεωργοκτηνοτροφικών δραστηριοτήτων, δείχνουν ότι η βλάστηση της ευρύτερης περιοχής, αναπτύχθηκε ανεπηρέαστη από ανθρωπογενείς δραστηριότητες, εκτός από την περίοδο της Εποχής του Χαλκού, λόγω εντατικής ξύλευσης. Η παρουσία charcoals στα προφίλ των τυρφώνων, σε συνδυασμό με το σύνολο γύρης, δίνουν ενδείξεις ότι οι πυρκαγιές αποτελούν, διαχρονικά, μέρος του φυσικού οικοσυστήματος. Τόσο από την εξελικτική πορεία της βλάστησης, όσο και από την παρούσα κατάσταση, φανερώνεται μια σταθερή παρουσία πευκοδάσους το οποίο διατηρείται παρά τις κατά περιόδους διακυμάνσεις των κλιματικών συνθηκών, των οποίων η, προφανώς μικρή, ένταση δε φαίνεται να το επηρεάζει σημαντικά

Chitosan Grafted Adsorbents for Diclofenac Pharmaceutical Compound Removal from Single-Component Aqueous Solutions and Mixtures

The main purpose of this study was to investigate the synthesis of some cross-linked carboxyl-grafted chitosan derivatives to be used as selective adsorbents for diclofenac (DCF) pharmaceutical compounds from aqueous mixtures. Four different materials were synthesized using succinic anhydride (CsSUC), maleic anhydride (CsMAL), itaconic acid (CsITA), and trans-aconitic acid (CsTACON) as grafting agents. After synthesis, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) were performed before and after DCF adsorption. In addition, a complete adsorption evaluation was carried out for all materials studying some important parameters. The optimum pH was 4; the amino groups of DCF can be protonated at pH = 4 (–NH+), so this groups can easily attract the clear negatively carboxyl moieties (–COO−) of the chitosan adsorbents. The Qm for CsTACON was higher than those of the other materials, at all temperatures studied. By altering the temperature from 25 to 35 °C, an increase (16%) of Qm (from 84.56 to 98.34 mg g−1) was noted, while similar behavior was revealed after a further increase of temperature from 35 to 45 °C, improving by 5% (from 98.34 to 102.75 mg g−1). All isotherms were fitted to Langmuir, Freundlich, and Langmuir-Freundlich (L-F) models). In addition, a kinetic model was proposed taking into account not only the interactions but also the diffusivity of the molecule (DCF) into the polymeric network. The behavior of the prepared chitosan materials in simultaneously removing other compounds (synergetic or antagonistic) was also evaluated by experiments performed in mixtures. DCF presented the highest removal from the mixture in the order: CsTACON (92.8%) > CsITA (89.5%) > CsSUC (80.9%) > CsMAL (66.2%) compared to other pharmaceutical compounds (salicylic acid, ibuprofen and ketoprofen). Desorption was achieved by using different eluants (either water or organic). The highest desorption ability was found for acetone (100% for CsTACON, CsSUC, CsMAL and 77% for CsITA) for all materials