Palynomorph Concentrations Research Articles

Palynofacies analysis and depositional environment of the upper Triassic Kurra Chine Formation: integrated by samples from sarta and Tawke oil fields and outcrop samples from sirwan valley in the kurdistan region, northern Iraq

Palynofacies (PF) analysis was conducted on 34 crushed samples of the Upper Triassic Kurra Chine Formation. These samples were collected from one outcrop sample and two production wells in northern Iraq. A 10μm nylon mesh sieve was used for the concentration of palynomorphs. Four palynofacies types were found in this study. PF1 was characterized primarily by amorphous organic matter (AOM), suggesting a distal suboxic-anoxic depositional environment. PF2 comprised of AOM, along with some Phytoclasts and palynomorphs, indicating a distal dysoxic-oxic shelf depositional environment. PF3 displayed an increasing volume of palynomorphs, signifying a distal dysoxic-anoxic shelf depositional environment. PF4 predominantly consisted of palynomorphs and Phytoclasts, representing a mud-dominated oxic shelf (distal shelf) depositional environment. Kerogen types were identified as type II, which is oil-prone in three palynofacies, and type III which is gas-prone in one palynofacies.

Features of spore and pollen composition of the Middle Pleistocene deposits of the Kenitra 1 section (Morocco)

A reconnaissance study of the Middle Pleistocene deposits of the Kenitra 1 section was carried out in order to check the concentration of palynomorphs here. The article presents the palynological characteristics of the paleosol. A low saturation of palynomorphs in the lower part of the deposits and a high content of pollen and spores in the upper part of paleosol 2 were established. Presumably, the lower part of the deposits can be compared with the transition zone from MIS 7 to MIS 6, and the upper part, with MIS 6. On the basis of palynological studies, landscapes and climate were reconstructed.

Terrestrial carbon isotope stratigraphy of the Eocene–Oligocene transition, Petrockstowe and Bovey basins, Devon, UK

The terrestrial sediments of the Petrockstowe and Bovey basins in Devon, UK were examined. Their age is considered to be Eocene and Oligocene. The sediments (kaolinitic clays, silts, sands, gravels, and lignites) from both basins were analysed for carbon isotopes of organic material, in conjunction with total organic carbon and palynological analyses used to unravel the type of and provenance of organic matter present. Within the Petrockstowe Basin, the lowermost interval examined shows a palynological distribution dominated by phytoclasts, whilst the upper part of the core is dominated by higher concentrations of palynomorphs (up to 90 %) and an increase in amorphous organic matter consistent (up to 37 %) with a change from sand-filled fluvial channels followed by an ephemeral lake or lake margin setting. Our palynological data from the South John Acres Lane Quarry section, Bovey Basin, show that within the lignites palynomorphs are high again (up to 95 %) consistent with them representing more ephemeral lakes or lake margins periodically exposed with mires. Our palynological data set further allows us to determine that isotope trends are not overly determined by the source of carbon in the basins. Our study suggests that the observed patterns were primarily produced by variations of the isotope ratios of terrestrial atmospheric carbon reservoirs. Even with our less than well constrained biostratigraphical control, the data indicate that the carbon isotope excursions seen in the Eocene and Oligocene could be associated with several transient carbon isotopic shifts (associated with the Paleocene–Eocene Thermal Maximum). Our findings therefore appear to lend support to the surface ocean and atmosphere behaving as coupled reservoirs at this time.

Continental influence on the fertilization of marine waters during the late quaternary in the south of the Brazilian continental margin

This study sought to understand the role of continental influence on ocean productivity along the late Quaternary based on the comparison between continental palynomorphs and paleoproductivity proxies from the marine sediment core SIS188. Retrieved from the slope of the Pelotas Basin at a depth of 1,514 m, the core documents the time interval between 47.8 and 7.4 cal ka BP, including the Marine Isotope Stages (MIS) 3, 2 and 1. The palynological content found in the core SIS188 indicates a typical flora of the southern Brazil highlands, which is at the same latitude as the core. Thus, continental input sources, such as wind-borne dust and discharges from the Mampituba and Araranguá rivers, would more likely account for the palynological content than the Brazilian Coastal Current (BCC). During the glacial intervals (MIS 3 and MIS 2), paleoproductivity (indicated by the proxies coccolith numbers, N Ratio, and TOC content) suggest the intensification of upwelling and transport of wind dust, the latter of which may have transported pollen grains to the core region. There is a concentration decrease of continental palynomorphs at the end of MIS 2, which is accentuated during MIS 1 when the sea level is higher. Paleoproductivity was high during MIS 1, especially from the Holocene onwards, although the concentration of continental-derived palynomorphs decreases sharply, showing that the rise in sea level interferes with the fertilization of marine waters far from the coast by continental input.

Mid- to Late Holocene (5200–980 cal YR BP) paleoenvironmental dynamics in the Ilha Grande, Brazil, assessed by terrestrial and marine microfossils

Ilha Grande is a Brazilian island that has a high vegetal biodiversity with a well-documented prehistoric human occupation but has few paleoenvironmental studies developed in this area. In view of this, multiproxy analysis of lagoonal sediments including radiocarbon dating were carried out on a 139 cm-long continental sediment core. The aim of our study was to recognise and explain environmental dynamics in this region during the Holocene (∼5200 cal yr BP). The palynomorphs indicate the continuous presence of Atlantic Forest under humid conditions during the last Holocene sea-level highstand, after 5200 cal yr BP. A phase of low palynomorph concentrations was followed by a marked increase in palynomorph accumulation and diversity which may be linked to the subsequent drop of the sea-level. Dinoflagellate cysts showed a higher accumulation at the base of the sediment core. The high accumulation of charcoal particles identified between approximately 3700 and 3000 cal years BP might indicate human activity related to the long-lasting bonfires kept burning by the inhabitants of the archaeological site of Ilhote do Leste.

Reconstruction of Paleoecology of Early Miocene Subsurface Deposits from Microflora in the Eboïnda Area (South-Eastern Côte d'Ivoire,West Africa)

The early Miocene palynoflora was recovered from well P1 located in the Aboisso area, about 175 km around of Abidjan (south-eastern Côte d'Ivoire, West Africa). Pteridophyta spores, angiosperm and gymnosperm pollen grains have been identified. The main objective of this work is to inventory all the palynomorphs encountered, to propose a local palynostratigraphy and to reconstitute the paleobotany of our study area during the Tertiary formations north of the lagoon fault. The samples were processed according to the classical procedure of extraction and concentration of palynomorphs. The lithology contains brown to black clays, coarse to fine sands, and reddish to motley clays. This study showed that the dominance of freshwater ferns such as Verrucatosporites usmensis, Laevigatosporites ovatus, Polypodiaceiosporites simplex, Cingulatisporites pseudocicatricosus and leiotriletes adriensis which evokes a swampy environment. Also the development of Bombacaceae (Bombacacidites annae), and the abundance of Pteridophyte spores of the Polypodiaceae family (Verrucatosporites usmensis, Laevigatosporites ovatus, and Polypodiaceiosporites simplex) indicate the climate was tropical with alternating dry and wet periods. Early Miocene sediments are placed in a continental type environment.

Multi-proxy indications of depositional evolution and paleo-natural disasters (flooding and fire) in the southern part of the Korean Peninsula during the Holocene

Understanding paleoenvironmental changes and corresponding driving forces can provide valuable information for predicting and preparing for future climate change. However, under the complex climate system, the driving mechanisms behind hydroclimatic variability in terms of timescales and magnitude are still unclear, and the various ecological responses are not clear. Here, we reconstruct the history of swamp evolution and climate changes in the southern part of the Korean Peninsula during the Holocene based on multi-proxy data (palynomorphs, microscopic charcoal, diatoms, grain size, total organic carbon, C/N ratio, and δ13CTOC data). The climatic conditions in the study area gradually became cold and dry due to the weakening East Asian summer monsoon (EASM) after ca. 5400 cal yr BP, as evidenced by the shift in vegetation communities from temperate broad-leaved forests dominated by Quercus to mixed conifer and deciduous broad-leaved forests with increased cold/dry-tolerant taxa. After ca. 4700 cal yr BP, microscopic charcoal concentration to terrestrial pollen concentration values are relatively high together with a sharp decrease in palynomorph concentrations and the proportions of arboreal pollen, representing open forest with fewer plants due to frequent wildfires. In addition, the quasi-millennial frequencies of seasonal fires (dry spring) and flooding (summer rainfall) were identified in our study area during the Late Holocene, which correspond to lower sea surface temperatures of the western tropical Pacific and stronger El Niño Southern Oscillation (ENSO) activity periods. After ca. 8200 cal yr BP, the depositional environment underwent gradual backswamp expansion due to high precipitation, strengthened EASM, and relative sea-level rise during the Early to Middle Holocene. During the Late Holocene, ENSO-driven extreme hydroclimatic variability, such as frequent flooding and fire, had significant impacts on not only swamp development with large fluctuations in water level but also long-term vegetation and aquatic ecosystem dynamics.

A guide to preparation protocols in palynology

A comprehensive, illustrated guide to the preparation (i.e. extraction, concentration and microscope slide production) of palynomorphs from samples of sediments, sedimentary rocks and other materials is presented. The traditional technique, based upon mineral acid digestion of the sample matrix, is subdivided into four phases. These are: sampling and pre-preparation; acid digestion; palynomorph concentration; and presentation of palynomorphs for study and archiving of materials. Modifications for preparing Quaternary and modern materials such as acetolysis are outlined, as are methods of preparation which do not use hazardous acids. One of the most effective non-acid preparation techniques uses sodium hexametaphosphate as a clay deflocculant and works well on clay-rich samples which are not intensely lithified. Hydrogen peroxide is another reagent which can be used for this purpose. The contamination of samples by material from other samples or modern pollen can lead to spurious data and interpretations. Strenuous efforts to avoid contamination should be made. Modifications of the traditional preparation technique are described for 14 specific sample materials. For example, many pure limestones only require digestion with hydrochloric acid. Moreover, coal is typically simply oxidised using nitric acid or Schulze’s solution then reacted with dilute potassium hydroxide solution to produce organic substances which are then rinsed away using water. Traditional preparation techniques are used for all palynomorph groups irrespective of their biological affinity, however certain of these require some specific modifications. For example chitinozoa and megaspores are substantially larger than acritarchs, dinoflagellate cysts, miospores and pollen, therefore modifications to the technique must be used, principally in the sieve sizes used. Some attempts have been made to automate palynomorph processing. The equipment for this is discussed, together with other technological solutions such as microwave digestion. Eight techniques closely associated with palynological processing and the microscopical observation of palynomorphs such as scanning electron microscopy are also reviewed.

Reconstructing Depositional Rates and Their Effect on Paleoenvironmental Proxies: The Case of the Lau Carbon Isotope Excursion in Gotland, Sweden

AbstractVariations in depositional rates affect the temporal depositional resolutions of proxies used for paleoenvironmental reconstructions; for example, condensation can make reconstructed environmental changes appear very abrupt. This is commonly addressed by transforming proxy data using age models, but this approach is limited to situations where numerical ages are available or can be reliably inferred by correlation. Here we propose a new solution, in which relative age models are constructed based on proxies for depositional rates. As a case study, we use the onset of the late Silurian Lau Carbon Isotope Excursion (LCIE) in Gotland, Sweden. The studied succession is a gradual record of shallowing upward in a tropical, neritic carbonate platform. As proxies for depositional rates we tested thorium concentration, carbonate content, and the concentration of pelagic palynomorphs. These three proxies were used to create relative age models using the previously published DAIME model. We applied these models to transform the δ13Ccarb values as well as concentrations of selected redox‐sensitive elements. The three relative age models yielded qualitatively similar results. In our case study, variations in depositional rates resulted in peaks of redox proxies appearing up to 76% higher when taken at face value, compared to when accounting for these rates. In the most extreme cases, our corrections resulted in a reversal in the stratigraphic trend of elemental concentrations. This approach can be applied and developed across depositional setting and types of paleoenvironmental proxies. It provides a flexible tool for developing quantitative models to improve our understanding of the stratigraphic record.

Cretaceous Oceanic Anoxic Event 2 in eastern England: further palynological and geochemical data from Melton Ross

The lowermost 1.45 m of the Welton Chalk Formation, including the regional sedimentary record of Oceanic Anoxic Event 2 (OAE-2), has been sampled at Melton Ross Quarry in eastern England, UK. The section is investigated for organic geochemistry and stable isotopes for the first time, while a detailed palynological study follows previously published preliminary results. It comprises a condensed interval that spans the Cenomanian–Turonian Stage boundary. A locally preserved, lower ‘anomalous’ succession (Beds I–VII) and a ‘Central Limestone’ (Bed A) are shown to correlate respectively with the pre-Plenus sequence and Plenus Bed at Misburg and Wunstorf in the Lower Saxony Basin (LSB), NW Germany. They are overlain by a succession of variegated marls (Bed B to Bed H), including the Black Band (Beds C–E), that can be correlated across eastern England. Based on a carbon isotope (δ 13 C) profile and dinoflagellate cyst and acritarch bio-event correlation, Beds B–H appear to be a highly attenuated post-Plenus equivalent of the LSB succession, including part of the ‘Fish Shale’. The δ 13 C profile shows possible ‘precursor’/‘build-up’ events in the lower succession at Melton Ross, with the main OAE-2 δ 13 C excursion occurring in the Central Limestone and overlying Beds B–H. The darker coloured marls from the Black Band and Bed G contain 1.43–3.47% total organic carbon (TOC), hydrogen index values of 78–203 mg HC/g TOC and oxygen index values of 15–26 mg CO 2 /g TOC, indicating type III and type II–III organic matter, of mixed terrigenous and marine algal sources. The corresponding palynological assemblages are dominated by marine dinoflagellate cysts, comprising mainly gonyaulacoid taxa, with subordinate terrigenous miospores, mainly gymnosperm bisaccate pollen, consistent with a distal marine setting. The interbedded lighter-coloured marls contain less than 0.4% TOC and lower proportions of miospores and peridinioid dinoflagellate cysts compared with the darker layers. This is suggestive of moderately raised levels of productivity during deposition of the darker layers, possibly related to greater nutrient availability from land-derived sources. The occurrence of the peridinioid taxa Eurydinium saxoniense and Bosedinia spp., together with higher proportions of prasinophyte phycomata in the darker layers, may also point to stimulation of organic-walled phytoplankton productivity by reduced nitrogen chemo-species encroaching the photic zone, possibly by expansion of an oxygen-minimum zone. Exceptionally high concentrations of palynomorphs (in the tens of thousands to lower hundreds of thousands per gramme range) in the darker layers at Melton Ross and eight other eastern England localities is consistent with increased quality of seafloor preservation in a low oxygen environment, coupled with a high degree of stratigraphic condensation. Two new dinoflagellate cyst species are described from Melton Ross, Canninginopsis ? lindseyensis sp. nov. and Trithyrodinium maculatum sp. nov., along with two taxa described in open nomenclature. Supplementary material : One pdf file, with detailed sample positions and descriptions, tables of supporting information (also available in Excel format), quarry photographs and a palynological distribution chart, is available at https://doi.org/10.6084/m9.figshare.c.4987205

Sedimentary organic matter from a cored Early Triassic succession, Georgetown (Idaho, USA)

The plant fossil record from Lower Triassic sedimentary successions of the Western USA is extremely meager. In this study, samples from a drill core taken near Georgetown, Idaho, were analyzed for their palynological content as well as their stable carbon isotope composition. The concentration of palynomorphs is generally low. The lowermost part of the drilled succession represents Dinwoody/Woodside Formation and contains spore and pollen assemblages with Permian and Early Triassic affinity. Representatives of lycophytes (Densoisporites spp., Lundbladisporites spp.) were found in the overlying Meekoceras Limestone, in agreement with middle Smithian assemblages elsewhere. Ammonoids and conodonts are extremely rare, but confirm a middle Smithian age. Bulk organic and carbonate carbon isotope composition provide a stratigraphic framework. Carbonate carbon isotope compositions are compatible with the Smithian–Spathian global trend, with a middle Smithian shift towards lower δ13C values followed by a late Smithian shift towards higher values. Bulk organic carbon isotope compositions have been influenced by changes in the constitution of organic matter. A comparison with other paired carbon isotope datasets from the same basin is difficult due to lithostratigraphic inconsistencies (Hot Springs, ID) or biochemical mediated disturbance of isotope signals (Mineral Mountains, UT).

Paleoceanographic and paleoclimatic reconstruction based on marine palynomorphs in the period 1811–1907 CE in the Magdalena Basin, Baja California Sur, Mexico

Biennial variations of marine palynomorph concentrations mirrored oceanographic conditions in the Magdalena Basin, Baja California Sur (Mexico), in the period from 1811 to 1907 (common era, CE), for which the sea surface temperature index (SSTI) showed predominantly negative anomalies. We analyzed 49 samples of laminated sediments taken from a core extracted at a water depth of 520 m. Changes in dinoflagellate assemblages and copepod egg abundances were compared to SSTI records and to El Niño Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) reconstructions. Copepods were the most abundant and showed a significant correlation with SSTI. Among the dinoflagellates, heterotrophs were the most abundant and did not correlate with SSTI. The lowest concentration of autotrophs showed a significant and inverse correlation with SSTI. The canonical correlation analysis also indicated that copepods and autotrophs were modulated by variations in SSTI. Dinoflagellate richness and concentrations and copepod egg concentrations were low, indicating low productivity, and these values coincided with the negative SSTI anomalies. In contrast, the increase in concentrations from 1881 to 1907 CE coincided with positive SSTI anomalies. Also, even when marine palynomorphs showed no significant correlation with either ENSO or PDO, their concentrations increased during age intervals with combined negative conditions (La Niña, negative PDO) and decreased during combined warm conditions (El Niño, positive PDO).

Palynological Characteristic of Dark Gray Clays in the Ivorian Onshore Basin at Southern Bingerville

Samples from two wells implanted at the level of the dark gray clay outcrop of Bingerville were the subject of this palynological study. The main objective of this work is to inventory all the palynomorphs encountered, to propose a local palynostratigraphy and to reconstitute the paleobotany of our study area during the Tertiary formations north of the lagoon fault. The samples were processed according to the classical procedure of extraction and concentration of palynomorphs.
 The high populations of dinocysts of the genus Lejeunecysta lata, Opreculodinium centrocarpum and Selenopemphix quanta as well as those of spores and pollens of the genre Magnastriatites howardii, Perfotricolpites digitatus, Pachydermites diederixi, Bombacacidites bombax, Retitricolporites irregularis, Retitriporites sp. Verrucatosporites usmensis are tributary to Oligocene.
 At the palaeobotanical and palaeoecological level, the highlighted palynoflora made it possible to characterize three environments, including mangroves, coastal plain, and rainforests.

Pollen calendars of Cartagena, Lorca, and Murcia (Region of Murcia), southeastern Iberian Peninsula: 2010–2017

Pollen allergens are one of the most important causes of respiratory allergies in industrialized countries. Aerobiological studies, including pollen and spore concentrations, allow for the defining of different palynomorph concentrations throughout the year. Pollen calendars summarize the aerobiological information of a locality in a single figure. They report which types of pollen are present at each time of the year and highlight the relative importance of some with respect to others. In this paper, the pollen calendar of three cities in the Region of Murcia, Cartagena, Lorca, and Murcia, is presented for the period 2010–2017. Sixty-three pollen types were identified in the bioaerosol of the Region of Murcia. Fourteen pollen types make up the pollen calendar of Cartagena, while 15 form those of both Lorca and Murcia. The spore types Cladosporium cladosporioides, Cladosporium herbarum, and Alternaria, have been included in the same format. The results show important qualitative and quantitative differences among the three cities. Lorca presents an aerobiological profile related to agricultural activities, while Murcia shows higher influence from anemophilous species coming from gardens and parks, and finally, given its proximity to the sea, Cartagena registers lower levels in most pollen types. The intensity of some of the pollen taxon and fungal types requires a deeper study of their responsibility for allergies in the area.

Fluvial pollen deposition in a mangrove ecosystem in south-eastern Brazil

Here palynological assemblages are presented from channel surface sediment samples from the Caceribu, Guaraí and Guapimirim-Macacú rivers located in an important area of the Brazilian coast (Guanabara Bay, State of Rio de Janeiro), in order to provide information relevant for the interpretation of palaeoecological records. The data indicate the predominance of pollen types from the Atlantic Forest in all samples and a relatively low representation of mangrove pollen, suggesting distant (regional) fluvial transport. Avicennia and Rhizophora were represented in those samples closer to the intertidal zone, Rhizophora being the most important. It was possible to verify a marked difference in pollen concentration/deposition among the three rivers, probably related to the different hydrodynamic pattern of each river. A low concentration of palynomorphs occurred in the Macacú-Guapimirim River, resulting from its higher flow, and there was a high deposition of palynomorphs in the sediments of Guaraí River, in response to its isolation from the hydrographic Guanabara Bay basin. It was possible to verify other interesting data, such as low palynomorph concentration in samples from near the mouth and an increase of palynomorphs in the upstream samples, mainly due to the more active action of the tidal currents. Meanwhile, the increase in the total concentration of the palynomorphs in the upstream samples coincides with the maximum reach of the saline waters and their meeting with the internal flow of the rivers.

Diversity and distribution of dinoflagellate cysts in surface sediments from fjords of western Vancouver Island (British Columbia, Canada)

Abstract A total of 31 surface sediment samples from 16 coastal inlets in five sounds of western Vancouver Island were investigated for dinoflagellate cysts and other palynomorphs. Well-preserved and abundant dinoflagellate cysts were recovered, including a total of 32 cyst taxa belonging to four families. Total dinoflagellate cyst concentrations vary two orders of magnitude, with concentrations between 2267 and 918,584 cysts g−1. The highest values were observed in samples from Tofino Inlet. Southern sites are characterized by cysts of autotrophic dinoflagellates, mainly Operculodinium centrocarpum sensu Wall & Dale 1966. Other abundant cysts of autotrophic dinoflagellates are Spiniferites spp. and cysts of Pentapharsodinium dalei. In general, other inlets in Quatsino, Kyuquot-Nootka and Clayoquot Sounds have lower total concentrations but have more cysts of heterotrophic dinoflagellates, mainly Round brown cysts, Brigantedinium spp., and Spiny brown cysts. Neroutsos Inlet is characterized by high concentrations of Arcellacean testate amoebae. Within inlets, cyst concentrations and assemblages vary. Near the heads of the inlets, concentrations are generally lower and assemblages are dominated by cysts of autotrophic dinoflagellates, mostly O. centrocarpum sensu Wall & Dale 1966. Concentrations of cysts produced by heterotrophic dinoflagellates and their proportions in the assemblages generally increase from the head to the mouth of each inlet. Measured sedimentary biogenic silica abundances (%Opal) have consistently higher values in Clayoquot Sound and lower values in Quatsino Sound. Within individual inlets, biogenic silica generally increases in the head to mouth direction. The trend in heterotrophic cyst abundances is similar. Correlations between total organic carbon (TOC), total nitrogen (TN) and terrestrial palynomorph concentrations in the sediments indicate that the organic material at sites near inlet heads are mainly derived from terrestrial input. A significant negative correlation between biogenic silica and TOC/TN ratio was observed in the dataset, but not between the total heterotrophic cyst concentrations and relative abundances of biogenic silica. Statistical analyses (PCA, RDA) indicate that the assemblages of dinoflagellate cysts and other palynomorphs, their spatial distributions, and sedimentary geochemical measurements are related to the regional environmental setting (e.g., latitudinal trends in weather, primary productivity, and upwelling) and local characteristics of the inlets (e.g., site location relative to freshwater input, inlet morphology and bathymetry, as well as possible anthropogenic influences). Process length variation of O. centrocarpum sensu Wall & Dale 1966 was measured and it is comparable to previous measurements in similar environmental settings, allowing seawater densities to be inferred. Cysts of Alexandrium spp. were found in most of the samples, with the highest abundance in the inlet heads of Kyuquot and Quatsino Sounds.

Nested cell strainers: An alternative method of preparing palynomorphs and charcoal

Centrifugation and sieving are essential techniques used in standard preparations of pollen and other palynological material. However, multiple centrifugation steps can potentially damage delicate palynomorphs and other microfossils, and the process of decanting after centrifugation can lead to loss of material. Traditional sieves often have a large surface area which makes manipulating smaller samples difficult and creates the need for potentially damaging techniques (e.g., sonication) to facilitate material through the sieve. We propose using stackable cell strainers as an alternative method for the preparation of pollen and charcoal samples. These sieves fit firmly on standard plastic 50ml centrifuge tubes and special rings allow the attachment of disposable syringes for suction. We demonstrate that the results of using cell sieves are comparable or better than those of traditional methods. Pollen counts from nine Holocene sites using the cell strainers showed similar concentrations of major palynomorphs in comparison to counts of samples processed following traditional methods. Visual comparison and counts of delicate pollen morphotypes, such as Pinaceae and Poaceae grains, indicated that fewer grains were damaged when cell strainers were used. Macrocharcoal preparations using cell strainers showed consistently lower counts than samples prepared using traditional methods, which may reflect lower rates of fragmentation of fossil charcoal during preparation. Finally, we demonstrate that nested cell strainers are also effective in processing lithified material and isolating and staining pollen from herbarium samples.

Sedimentary, Geochemical and Micropaleontological Responses to Sea Level Variations in the Vitoria Estuary, Espírito Santo

AbstractMarine insertion indicators in the Vitoria estuary (ES) revealed relative variations in sea level during the Holocene in three sediment cores. Sedimentological, geochemical (C/N ratio), and paleontological (shells and palynomorphs) analysis and14C dating associated five sedimentary facies to different estuarine deposits. A C/N ratio <10 at the core base indicated organic matter of marine origin. Moving up the cores to 110–150 cm, an abrupt increase in C/N to 26–63 in every core suggests the sudden entry of higher plants into the estuary, potentially the moment sea level retreated. High continental (10,743 palynomorphs/g) and low marine palynomorph concentrations (323 palynomorphs/g) suggest a primarily continental source even during transgression and at high sea level. Around 8973 cal BP, an open bay already existed in the region of Vitoria. Sea level potentially exceeded the current level around 7110 cal BP. The transgressive maximum was at 5567 cal BP. Marine insertion indicators, such as marine shells, low C/N ratios and foraminiferal linings, did not always respond directly to sea level oscillations. These discrepancies probably result from lateral variations in sedimentary deposits from transport patterns and from variations in organic matter and palynomorph preservation due to differences in river and obstacle proximity.

High-resolution palynological record of Holocene climatic and oceanographic changes in the northern South China Sea

For the first time, palynological records of terrestrial palynomorphs and dinoflagellate cysts are investigated in a sediment core from the northern South China Sea (SCS) covering the last 12,500years. Both terrestrial and marine palynomorph records show strong signals of the sea-level change during the studied interval. The highest herb pollen content was associated with extensive grasslands on the exposed shelf at the low sea-level stand during the Younger Dryas and early Holocene. The increase in fern spores and decrease in concentrations of dinoflagellate cysts and terrestrial palynomorphs was observed during the sea-level rise interval from 12,500 to ~6800 (or 6000) calyr BP. Then, the sea level became stabilized and consistently low dinoflagellate cyst abundances and high abundances of fern spores were recorded.A high abundance of Impagidinium in the period ~12,000–10,400calyr BP possibly resulted from increased input of western Philippine Sea waters into the SCS and the branching of the Kuroshio Current. A short-term decrease of Impagidinium at ~11,700–11,000calyr BP corresponding to the MWP-1B event might be associated with input of the East China Sea waters through the Taiwan Strait.The relationship between the sedimentation rates and the concentrations of terrestrial palynomorphs indicates a water-dominant transport for pollen and spore dispersal prior to ~6300calyr BP, whereas wind transport became more prominent thereafter. The timing of this change corresponds to the highest sea-level stand at ~6800–6000calyr BP, when the present oceanographic setting was formed. The mid-Holocene Optimum can be seen by the highest abundance of subtropical-tropical broad-leaved arboreal pollen and by the highest abundances of Dapsilidinium pastielsii. Three strengthened winter monsoon intervals at ~5500calyr BP, 4000calyr BP, and 2500calyr BP are reflected by increases in Pinus pollen content after the present oceanographic condition formed.

A mid-Holocene vegetational and anthropogenic record in the Guanabara Bay region, Rio de Janeiro State, SE Brazil, assessed by palynological and charcoal data

Palynological and charcoal fragment analyses of Guanabara Bay sediments, as well as radiocarbon dating, were carried out on one 220 cm long sedimentary core collected from the northeast sector of the bay, near the São Gonçalo coast. This study aims at recognising and explaining the environmental history of this region during the mid-Holocene, and to identify the anthropogenic influences on it. The palynological data indicate the predominance of ombrophilous forest vegetation in the Guanabara Bay Hydrographic Basin at c. 6500 calendar years bp. During this period (pollen zone 1), the concentrations of pollen grains and spores may still have been controlled by the Holocene Maximum Transgressive Event. After a phase of low concentrations of palynomorphs, there was a considerable increase in the accumulation patterns of pollen and spore grains (pollen zone 2). This increase can probably be related to the retreat of the sea level event after the Holocene Maximum Transgressive Event. The 75 cm of the core top (pollen zone 3) provide clear evidence of human influence in the area, which is inferred from the significant reduction in ombrophilous forest pollen grains, the significant increase in herbaceous pollen grains, the presence of exotic pollen types (Eucalyptus and Pinus), and high concentration of carbonaceous particles.