Pollen Recovery Research Articles

Using pollen in turbidites for vegetation reconstructions

ABSTRACTTurbidites, deposited by sub‐aqueous gravity flows, are common in sedimentary archives worldwide and present a unique challenge and opportunity when reconstructing past vegetation through pollen analysis. When sampling pollen from a sediment core for palaeovegetation records, it is common practice to target background sediments (i.e. pelagic sediment) and avoid sampling turbidites, as they are presumed to portray a misleading picture of past vegetation. This assumption stems from our limited understanding of pollen abundance and distribution through turbidites, meaning that palynologists overlook deposits that could potentially be used to reconstruct past vegetation and climate. We present pollen assemblage and sedimentological data from four recent (<150 years) deep marine turbidite deposits from the Hikurangi Subduction Margin, Aotearoa‐New Zealand, with the aim of understanding the abundance and distribution of pollen in fine‐grained turbidites. We find that pollen is diluted in the bases of turbidites, but despite this dilution, the proportions of different pollen taxa remain consistent through each turbidite. These results confirm that pollen can be sampled from turbidites for palaeovegetation reconstructions and that sampling the fine‐grained upper parts of turbidites will provide the best pollen recovery.

E‐PoSa: A novel and effective tool for sampling pollen directly from flowers

Abstract Pollinator insects are declining worldwide, also due to the alteration of their diet with severe implications on their health status. Pollinators diet relies mainly on flower rewards (i.e. pollen and nectar), and a precise characterization of their chemical composition is crucial in defining pollinators' nutritional ecology. In this context, the pollen represents a challenging source to investigate, especially due to operative challenges during collection operations and to the small amounts produced per flower. Here, we designed and tested a novel, easy‐to‐assemble tool for pollen sampling: E‐PoSa (Electronic Pollen Sampler), based on the use of a portable vacuum cleaner. We compared it with some of the most used sampling methods for pollen (i.e. anthers sieving and sampling of the whole anthers) by looking at the differences in their quantitative recovery and nutritional profile. Its applicability in ecological studies was also corroborated by an assessment of its recovery rate obtained from a panel of wildflower species in an operational environment. The data obtained showed a significantly higher pollen recovery capacity of E‐PoSa compared with the conventional sieving approach and the success in retrieving enough pollen to conduct phytochemical analyses from a broad range of flower morphologies in the field. Our results also demonstrated that high purity pollen can be collected with E‐PoSa and that the device does not introduce any significant variation in the nutritional analysis compared with the conventional sieving. This new sampling approach represents a cheap and easy‐to‐assemble tool encouraging its future use not only in the field of pollen nutrition but also in a wide variety of other contexts related to pollination ecology. Acknowledging the potential influences of the sampling techniques and moving towards shared standardized field protocols will advance the comprehension of species interactions and foraging patterns of pollinators and their nutritional needs.

PLEISTOCENE PALYNOLOGY OF THE WAIPONA BASIN, PAPUA

The Pleistocene sediment from a single well drilled on the back bone of Papua provides good pollen recovery which shows the mixture of the Australian and Asian elements. The well drilled the sediment more than 3000 meter deep which is mostly assigned to Pleistocene age. Only small part of the basal section belongs to Pliocene age. In order to obtain accurate interpretation, the age interpretation is also defined using other disciplines including foraminifera and nannoplankton. The Australian affinity appears as an origin since this island has derived from the Australian continent. On the other hand, the existence of Asian palynomorphs within the studied sediment indicates the dispersal of Asian flora into East Indonesia following the arrival of the Australian plates at about the end of Oligocene. The Asian taxa then migrated to the land mass of New Guinea which rose above sea level from about Middle Miocene onward. In the studied section, shallow marine sediment in the upper interval contains sufficient palynological assemblages which clearly indicate climatic changes from dry or seasonal to wet climate as reflected on the changes of the proportion of dry/ seasonal and wet climate indicators. Unfortunately, due to low pollen recovery, the climate condition of the lower interval can be hardly interpreted. This could have happened because the sediment of the lower interval was deposited in deep marine environment, which was situated far away from the pollen sources in the continent.

Paleocene–Eocene palynomorphs from the Chicxulub impact crater, Mexico. Part 2: angiosperm pollen

At the end of the Cretaceous Period, an asteroid collided with the Earth and formed the Chicxulub impact structure on the Yucatán Platform. International Ocean Discovery Program (IODP) Expedition 364 drilled into the peak ring of the Chicxulub impact crater. The post-impact section of the core was sampled for terrestrial palynological analysis, yielding a high-resolution record ranging from the early Paleocene to the earliest Eocene (Ypresian), including a black shale deposited during the Paleocene–Eocene Thermal Maximum (PETM). The IODP 364 core provides the first record of floral recovery following the K–Pg mass extinction from inside the Chicxulub impact crater. The systematic taxonomy of the angiosperm pollen provided here follows a separate publication describing the systematic paleontology of the plant spores and gymnosperm pollen from the IODP 364 core (Smith et al. 2019). The Paleocene section of the core is nearly barren, but with unusually high relative abundances of the angiosperm pollen Chenopodipollis sp. A (comparable to the Amaranthaceae), possibly indicating an estuarine pollen source. Pollen recovery is higher in the PETM section, and variable but generally increasing in the later Ypresian section, with excellent preservation in several samples. Estimated absolute ages of several potentially useful regional biostratigraphic events are provided. One new genus (Scabrastephanoporites) and five new species (Brosipollis reticulatus, Echimonocolpites chicxulubensis, Psilastephanocolporites hammenii, Scabrastephanoporites variabilis, and Striatopollis grahamii) are formally described.

POLLEN RECORD OF THE PERMIAN MARINE SEDIMENTS FROM WEST TIMOR

This is the fi rst publication to present palynological study on the Permian marine sediments of West Timor. This is aimed to evaluate its palynomorph content. Similar studies have been performed on the Permian sediments which mostly focus on non-marine sediments. 15 surface samples were collected from Lilana river outcrop which comprises the alternation of calcareous shale and sandstone. This outcrop is assumed to represent some parts of Bisane Formation. Standard preparation methods were employed to extract palynomorphs including acid maceration and oxidation. This study applies quantitative method which requires counting of palynomorphs in each sample. This study provides low to moderate pollen recovery which mostly consists of striate and non-striate bisaccates as well as trilete monosaccates. The age restricted taxa appearing in the non-marine sediments also present in the studied samples to mark Permian age such as Protohaploxypinus samoilovichi, Lunatisporites pellucidus, Falcisporites australis, Plicatipollenites malabarensis and Cannanoropollis janakii. On the other hand, common occurrence of marine dinofl agellates of Dapsilidium langii and Veryhachim reductum combined with abundant macrofossil of chrinoids confi rm a shallow marine paleoenvironment. Common green algae of Tasmanites sp. is a firmed evidence for the appearance of potential source rock of hydrocarbon within the Permian shallow marine sediments of West Timor.

Pollen analyses for pollination research, acetolysis

Analysis of the pollen associated with pollinators can reveal their role in pollination, the habitats and plants they visit, from where they migrated, what they eat, and dispersal patterns in and around cropping systems. However, finding pollen on and or in a pollinator depends on the technique used to recover the pollen. Acetolysis can be used to recover pollen from internal insect tissues (gut, alimentary canal, crop, etc.), external tissues (proboscis, legs, eyes, etc.) or both.Acetolysis is the best technique for recovering pollen because any tissue is dissolved and lipids and debris are removed from the sample and the pollen grains.This makes the diagnostic characteristics of the pollen grains more visible so that accurate pollen identification can be made.By using the proper technique, better pollen recovery can be made and thus better data can be obtained.

Pollen extraction from insects

Numerous insect species feed on the pollen, nectar and other plant exudates that are associated with flowers. As a result of this feeding activity, pollen becomes attached to the insects. Analysis of this pollen can reveal what insects eat, their dispersal patterns in and around cropping systems and their role in pollination. However, finding pollen on and/or in an insect depends on the technique used to recover pollen from the insect. Six different techniques are described in detail that have been used to recover pollen from a variety of insects including pests such as boll weevils, Mexican corn rootworms and corn earworm moths. These techniques can be use to recover pollen from internal insect tissues (gut, alimentary canal, crop, etc.), external tissues (proboscis, legs, eyes, etc.) or both. By using the most appropriate technique, better pollen recovery can be made and thus better data obtained.

Pollen analyses for pollination research, unacetolyzed pollen

Pollinators feed on the pollen, nectar, and other plant exudates that are associated with flowers. As a result of this feeding activity, pollen becomes attached to them. Analysis of this pollen can reveal what they eat, their dispersal patterns in and around cropping systems, and their role in pollination. However, finding pollen on and or in a pollinator depends on the technique used to recover pollen. Two very easy techniques are described in detail that have been used to recover pollen from a variety of pollinators including beneficial and harmful insects, spiders, bats, and other pollinators. These techniques can be used to recover pollen from internal tissues (gut, alimentary canal, crop, etc.), external tissues (proboscis, legs, eyes, etc.), or both. By using the proper technique, better pollen recovery can be made and thus better data can be obtained about the pollinators, the foods they eat, the plants they pollinate, their migration routes and source zones.

Generation, transport and preservation of armoured mudballs in an ephemeral gully system

Armoured mudballs have been reported from modern fluvial catchments and preserved in ancient (Quaternary and older) sedimentary sequences. Despite many descriptions of mudballs in the literature there is little systematic analysis of their physical properties, genesis, transport and deposition within alluvial sequences. This study uses two adjacent catchments developed on identical geology in southeast Spain that offer a unique opportunity to examine the key controls on armoured mudball development as one catchment produces armoured mudball whilst the second does not. Field survey using a Total Station together with laboratory tests for material composition and aggregate stability were used to examine the catchment and the armoured mudballs. The results show that the generation of the armoured mudballs is heavily dependent on the correct sediment supply (suitable aggregates to act as mudball ‘seeds’, and suitable fragments to source the armour) and good slope-channel coupling within the catchment. Coupling is facilitated by steep gully sides which deliver the weathered blocks of marl (mudball ‘seeds’) to the gully floor. The ‘seeds’ form the core of the mudballs in the ’mudball factory’ zone. If the ‘seeds’ are subjected to sealing by moisture from rainfall the mudball will hold together through negative pore pressures and can be transported by the ensuing gully flow. As the mudball rolls it picks up a surface armour which becomes embedded into the mudball. With longer transport paths the turbulent nature of the flow creates spherical mudballs which are size sorted downstream by the hydraulics of the flow rather than attrition. Armoured mudball deposition occurs within unit braid bars in areas of waning flow (due to transmission losses), within vegetated, point or mid-channel bars. The armoured mudballs are preferentially deposited within the coarser bar head of these depositional units, with smaller marl fragments forming the finer bar tail. Trenching of the bars reveals that the armoured mudballs are preserved in the subsurface although they may become increasingly flattened upon burial at depth, and may be difficult to recognise due to disaggregation by roots. This study suggests that armoured mudballs recognised in ancient alluvial sequences imply seasonality of climate and good slope-channel coupling within the catchment area, and that they are capable of transporting delicate flora undamaged, making them good targets for pollen recovery in ancient alluvial sequences. Where armoured mudballs were present but go unrecognised in the ancient record the mode and energy of transportation and deposition of the fine sediment may be misinterpreted as the fines are in fact being transported as bedload rather than suspended load. The armoured mudballs have also been noted to transport pristine microfauna such as ostracod shells from the source area material. This may provide challenges to palaeoenvironmental interpretations of the mud-dominated unit as environmentally significant fauna may not be contemporaneous with the unit.

Descriptions of melissopalynological methods involving centrifugation should include data for calculating Relative Centrifugal Force (RCF) or should express data in units of RCF or gravities (g)

Techniques of pollen recovery involving centrifugation of honey pollen (melissopalynology) described in certain publications are difficult to 1) reproduce and 2) compare to other melissopalynological methods because dimensions of the centrifuge rotor were not described. Centrifugation data should be stated either in units of Relative Centrifugal Force (RCF) or gravities (g), or the data should be stated so RCF can be calculated using revolutions per minute (RPM) and the dimensions of the centrifuge rotor.

An unusual appearance of a common pollen type indicates the scene of the crime

Forensic palynology is a useful source of evidence in cases of violence committed in the open. A young girl was grabbed off the street, threatened and brutally raped. During the investigation the exact place of the rape became an issue. Growing around the scene identified by the victim were shrubs identified as Coprosma, a common New Zealand plant and one that produces abundant, easily wind-dispersed pollen. Abundant Coprosma pollen was found at the scene. The pollen were unusual in that the site was very damp, encouraging fungal growth, and fungal hyphae had penetrated the pores of many of the tricolporate pollen grains. Some grains had fungal spores inside. Coprosma pollen identical in preservational characteristics and morphology to those from the scene and containing fungal hyphae and spores were found in considerable numbers on the victim's clothes. This and rare Coprosma pollen grains and fungal remains recovered from vaginal swabs provided evidence that she had been at the scene where she claimed to have been raped. The diversity of pollen types recovered from the clothing in this case provides further evidence of the usefulness of clothing in picking up and retaining pollen from crime scenes and that obvious staining on clothes is not a pre-requisite for good pollen recovery. It also demonstrates the importance of collecting samples from different parts of the same garment in order to get a full picture of events since different parts of a garment can come into contact with different plants or different parts of the ground in a scuffle. It is also demonstrated that significant evidential material can be collected from the body, in this case from vaginal swabs from the victim. Forensic palynology should be considered in every case of violent assault, especially, but not exclusively, when having occurred in an open area subject to extensive pollen settlement.

The use of ETOH for the dilution of honey*

Since the beginning of honey production, certain honey types are preferred because they taste better, are better for cooking, or do not rapidly crystallize. Pollen found in honey is used to determine the honey's type. Techniques used to extract pollen from honey vary in the amount of honey examined, the amount of water used to dilute the honey, and the time and speed of centrifugation. These variations address the disparity in pollen recovery that is due to the specific gravity and sinking rates of the different pollen types. Ethyl alcohol (ETOH) was used as a dilution liquid for honey and compared to two water-dilution techniques, one with a short centrifugation time (1 minute) and the other using a long centrifugation time (10 minutes). The ETOH samples were centrifuged for 3 minutes. All samples were centrifuged at 4000 r.p.m. Significantly higher pollen concentration values were found in the ETOH-diluted samples. Pollen concentration values of the ETOH-diluted samples were 5.26 times greater than water-diluted, short centrifugation samples, and 3.26 times greater than water-diluted, long centrifugation samples. ETOH-diluted samples produced 16% more taxa than the water-diluted short centrifugation technique, and 10% more taxa than the water-diluted long centrifugation technique. The pollen spectra were not consistent across the three techniques. Additional research is needed to determine the efficiency of other ETOH concentrations in recovering pollen from honey. We recommend that the ETOH-dilution technique become the standard technique for the extraction of pollen from honey for pollen analyses because of the improved pollen recovery.

Simultaneous Extraction of Phytoliths, Pollen and Spores from Sediments

Archaeological sediments often offer opportunities to examine local palaeoenvironmental conditions from analysis of included microfossils. On-site conditions commonly vary, and thus so do the preservation conditions for microfossils. Consequently, a range of palynological preparation techniques are commonly used. While different types of microfossils provide valuable palaeoenvironmental information, the use of separate extraction methods for different microfossil types may be both time- and resource-consuming, especially where the recovery predicability is low. This paper examines the possibility of combining preparation techniques for three commonly encountered microfossils—pollen, spores and phytoliths—by comparing pollen extractions using heavy liquid extraction and standard pollen recovery procedures. Although the use of heavy liquids for pollen and spore preparations has been well-documented, for several reasons it has not been a favoured technique for pollen extraction. The research reported here shows that for most of the sediments tested, heavy liquid extraction procedures produced comparable results to those arising from standard pollen extraction techniques. For oxidized sediments, especially, more reliable results are likely to be obtained from heavy liquid extraction procedures than from those employing acetolysis. Overall, heavy liquid procedures allow complementary suites of data to be investigated with the least cost and effort, thus enabling palynologists and phytolithologists to adopt more effective research practices for environmental reconstruction.

Mid-Holocene hemlock decline and diatom communities in van Nostrand Lake, Ontario, Canada

Terrestrial ecosystem disturbances inferred from the fossil hemlock pollen decline (ca. 4,800 BP) and recovery (ca. 3,800 BP) affected van Nostrand Lake, including the diatom communities. Ecological models suggest the lake responded by eutrophying, reflecting higher nutrient influx resulting from increased erosion. A decline in lake productivity followed as the forest vegetation recovered and erosion slowed. Lastly, as the forest switched from early and middle successional species to mature species, lake productivity increased as erosion increased nutrient inflow, especially phosphorus. However, this eutrophication response was delayed or buffered, perhaps due to wetland development surrounding the lake. The lake never fully returned to its initial, pre-hemlock decline state, but oscillated between more eutrophic and more mesotrophic or oligotrophic stages, possibly reflecting other disturbances in the catchment and climatic change.

Pollen recovery in atmospheric samples collected with the Rotorod Sampler over multiple-day periods such as weekends.

Conventional wisdom holds that multiple-day samples should not be obtained with the Rotorod Sampler because sampling efficiency declines over long sampling periods such as weekends. The purpose of this present investigation was to test this position under experimental conditions. Atmospheric pollen samples were collected over 24-hour, 48-hour, and 72-hour periods by five Rotorod Samplers operated in a compact sampling array. Pollen counts obtained from the latter two sampling periods were compared with corresponding values computed from 24-hour samples. Differences in pollen recovery were assessed using Pearson's correlation coefficient and paired comparisons t-tests. Two hundred seventeen atmospheric samples were obtained between March 30 and October 8, 1998. Differences between the 48-hour and 72-hour samples and their computed counterparts were not statistically significant when the atmospheric pollen concentration was less than 100 pollen grains per cubic meter of air (p/m3). At higher pollen concentrations large quantitative and statistically significant differences were noted. These data suggest that particle loading on Rotorod collector rods caused sample quality to deteriorate when atmospheric pollen concentrations exceed 100 p/m3. Multiple-day sampling periods appear to be justified when the atmospheric pollen concentration is less than this threshold. Adjusting the Rotorod Sampler's duty cycle may offer a means to collect samples over periods longer than 24 hours during times of the year when pollen shed is heavy.

An improved method for pollen analysis of honey

Filtration, rather than centrifugation, was investigated as a first step to extract pollen from honey. The filter with adhering pollen and spores was then acetolyzed in a 1.5 ml microcentrifuge tube to speed up the remaining steps of sample preparation. Various filters were tested and only those in polyester, cellulose, and cellulose acetate and poly-acetate had no deleterious effect on pollen acetolysis. Among these, fast filtration of diluted 10 g honey samples was possible with polyester and cellulose acetate filters, but polyester fibers trapped some pollen. Cellulose acetate membranes 47 mm in diameter with 0.8 μm pores (Sartorius SM111-04-47N) permitted the filtration of honey samples in less than 3 min and the filters dissolved totally during acetolysis releasing the pollen. With these filters, a new method based on filtration and followed by acetolysis in microcentrifuge tubes was developed and compared with standard pollen analysis starting with centrifugation at 1700 g (3000 rpm) for 10 min. Pollen recovery assays were conducted with a mountain honey and a test honey made of pollen-free honey to which pure pollen of Castanea, Helianthus, and Lilium was added. Significantly more pollen was recovered with the new method than with the usual one with both honeys. Also, the pollen spectrum of the test honey treated with the new method was similar to that of the pollen added originally, while it was significantly different when the test honey was processed with the standard method. Thus the new method significantly improved pollen extraction quantitatively and qualitatively, while decreasing sample preparation time by 50% and using less reagents and cheaper equipment.

Late Quaternary vegetational history of the Enga province of Upland Papua New Guinea

Late Quaternary vegetational history of the Enga province of Upland Papua New Guinea