Palynology of holocene peat bogs from the central Venezuelan andes

A sequence of six Holocene peats in a river terrace in Páramo de La Culata was studied and compared with present-day peat deposits. The pollen analysis has shown that this region has been a humid páramo since about 7500 years B.P. At about 6000 years ago, pollen-rain input greatly decreased, reflecting poor local and adjacent vegetation. This is interpreted as representing a lowering of the average temperature of the region during a short time.     

Spatial structure and regeneration of Tetramerista glabra in peat swamp rain forest in Indonesian Borneo

We examined the spatial structure and regeneration of Tetramerista glabra, a dominant canopy tree in peat swamp rain forest in Borneo (West Kalimantan, Indonesia). T. glabra has strong spatial structure that changes dramatically during the life cycle; seedlings were highly aggregated, saplings were random and trees were evenly distributed. Germination and seedling relative growth were highest within canopy gaps, but seedling densities were highest at gap edges. Concentration of seedlings in gap edges, rather than localized seed dispersal, was responsible for seedling patchiness. The slope of the relationship between relative growth rate and seedling height decreased from gap, to gap edge to understory habitats, suggesting that competition within the seedling layer is more important in gaps than in the understory. The processes that break down seedling aggregation, leading to over-dispersion of trees, must be density dependent, but remain unknown.     

Pollen analysis and dynamics of a peat deposit in Carnarvon National Park,central Queensland

A peat deposit within the valley of Louisa Creek in the central highlands of Queensland formed because the valley is incised below the water table in the Precipice Sandstone, an important Jurassic aquifer in the Great Artesian Basin. Peat growth appears to have been rapid, reaching a maximum depth of some 4 m in 1000 years. The pollen record preserved in the peat indicates that the vegetation communities have not altered over this period except for recent modifications perhaps attributable to increased salinity and the influence of cattle grazing. Both the Louisa Creek peat and the floodplain sediments on the Nogoa River downstream testify to a dynamic geomorphic environment. The geomorphic setting and the location of this site on the dry-subhumid/semi-arid boundary in Queensland, suggest that minor climatic shifts have had a substantial environmental impact leading to alternating conditions of scour and fill of valley sediments.     

Sexual dimorphism in Laccopithecus robustus, a late miocene hominoid from China

Laccopithecus robustus is a siamang-sized fossil ape from the Miocene site of Lufeng, China. The species is known from a partial cranium, numerous mandibles, and scores of isolated teeth. This species shows striking dental similarities to Pliopithecus from the Miocene of Europe and a number of cranial similarities to extant gibbons. Laccopithecus differs from extant gibbons and resembles other fossil and extant apes in showing marked sexual dimorphism in the size and shape of the canines and anterior lower premolars. Evidence for sexual differences in either the size or shape of other teeth is less clear. There is some evidence for a sexual size dimorphism based on the variability of molar teeth.     

Neomussaenda (Rubiaceae), a new genus from Borneo

A new genus, Neomussaenda is described to accommodate the species Greenea xanthophytoides and the new species Neomussaenda kostermansiana , described here. Neomussaenda is endemic to Borneo and differs from the genus Greenea in the induplicate-valvate aestivation, shape and indumentum of the corolla, heterostyly, bifid stipules, pollen morphology, seed exotestal cells with tuberculate inner wall, ideoblasts filled with numerous minute druses, and fruits not opening while attached to the inflorescence, but may open later loculicidally by decay. It is close to the genera Pseudonmussaenda and Schizomussaenda , with which it shares the induplicate-valvate aestivation and fruits with a splitting zone for loculicidaly dehiscence. Neomussaenda is placed in the tribe Isertieae.     

The antibacterial activity of a humic preparation made from the therapeutic peat mud of the Dzalal Abad deposit in Kirghizia]

The humic acid from the Dzhalal Abad therapeutic peat muds has been extracted to reveal the mechanisms of interaction between humic acid and microelements in therapeutic muds and to study the mud physiologically active factor. A complex compound of copper with humic and aminoacetic acids has been obtained, their physicochemical and antibacterial properties have been studied.     

Palynological evaluation of selected honeys from Romania

Fifty-four honey samples collected over two consecutive harvest seasons (2009–2010) from different floristic areas of Romania were analysed. A melissopalynological analysis including qualitative and quantitative analyses was carried out in order to identify the principal pollen types in Romanian honeys and therefore, the important plants exploited by Apis mellifera in this country. Seventy-seven pollen types from 35 botanical families were identified. The main pollen forms were: Brassica napus-type, Tilia, Helianthus annuus, Robinia pseudoacacia, Prunus, Castanea sativa, Fragaria-type and Plantago-type. Honey samples were classified as: acacia honey (Robinia pseudoacacia), lime honey (Tilia), rape honey (Brassica napus-type), sunflower honey (Helianthus annuus), cherry honey (Prunus). Three of them were honeydew honeys whereas the others were all polyfloral. The results from this study can be used as a palynological baseline data of Romanian artisanal honeys.     

Cyanoneuron (Rubiaceae), a new genus from Borneo and Sulawesi

The genus Cyanoneuron is established to accommodate three Bornean and Sulawesi species previously placed in Myrioneuron . Two new species: C. grandiflorum and C. pedunculatum are described. All five species are illustrated. A survey of the character states including vegetative, inflorescence, floral, fruit, pollen, seed morphology and anatomy is given. The chromosome number has been counted for C. cyaneum, C. grandiflorum and C. pubescens. Cyanoneuron is tentatively included in the tribe Hedyotideae, but its affinity to genera inside this tribe is unknown.     

Mineralization rates of peat from eroding peat islands in reservoirs

Reservoirs are sources of greenhouses gases to the atmosphere, primarily due to organic carbon mineralization in flooded plants and soils to carbon dioxide (CO₂) and methane (CH₄). Floating peat islands are common in reservoirs that inundated peatlands. These islands can decompose on mass, or small pieces of peat can erode from islands to decompose in the water column or on the bottom of reservoirs. Here we used large 450 liter sealed enclosures to measure mineralization rates of small peat pieces and larger peat blocks collected from floating peat islands. Mineralization rates were calculated by quantifying dissolved inorganic carbon (DIC), CO₂ and CH₄ accumulation within the water and headspace of the enclosures over time. We found that peat did decompose under water, but rates of mineralization of peat pieces were not different than rates of mineralization of larger peat blocks. Mineralization rates ranged between 59 and l40 g C g^–1 d^–1. Peat pieces acidified the water, shifting the bicarbonate equilibrium to almost exclusively dissolved CO₂, which was then readily able to flux to the atmosphere. We estimated that 2.4–5.6% of peat carbon was mineralized annually, suggesting that fluxes of CO₂ and CH₄ from reservoirs that flood peatlands could last at minimum 18–42 years from this carbon source alone.     

Orchidantha inouei (Lowiaceae), a new species from Borneo

A new species, Orchidantha inouei , is described from Sarawak. Two types of paracladium in the inflorescence are reported with a discussion on the inflorescence morphology of Lowiaceae.     

Late holocene history and vegetation dynamics of a floodplain alder carr: A case study from eastern Bohemia, Czech Republic

Vegetation development in the lowland floodplain alder carr “Na bahně” (eastern Bohemia, the Czech Republic) has been studied by means of pollen and macrofossil analyses and combined with vegetation analysis performed over the last 70 years. Local successional changes started with an oxbow lake (160 cal BC) which has later terrestrialised (630 cal AD). Then it changed from a typical alluvial fen into aSphagnum-dominated spring mire (950 cal AD) supplied by water arising from a river terrace surrounding the locality from three sites. In the centre of this wetland a small patch of alder carr developed (100 cal. AD), showing some tendency towards cyclic succession. The alder carr alternated several times with an openCarex fen (1100 cal AD to recent). The last fen-to-alder carr transition has been documented by direct observation during this century. Possible autogenic and allogenic factors driving the succession are discussed. The model of autogenic cyclic succession corresponds well with direct field observations and can be used to interpret alder carr structure, its dynamics, and function.     

Palynological characteristics of different unifloral honeys from Greece

Three hundred and twenty-nine Greek honey samples of different botanical and geographical origin were collected and examined by organoleptic evaluation, melissopalynological analysis, measurement of electrical conductivity and colour. The results showed that 208 samples were unifloral with 178 of them representing the main types of unifloral honey produced in Greece; that is fir, pine, chestnut, cotton, orange and thyme honey. All honeys had the sensory characteristics typical of their origin and complied with the electrical conductivity standards set by Council Directive 2001/110/EC.

Fir and pine honeydew honey had a low honeydew element/pollen (HDE/P) ratio and belonged to Maurizio's Classes II or III. The pollen types identified in these honeys ranged from 11 to 45%. Chestnut nectar honey contained >90% chestnut pollen, had a total number of plant elements of >245,000/10?g, and low pollen diversity. Cotton honey contained 1.2 to 16.5% cotton pollen, belonged to Maurizio's Class II, and had 22 pollen types, with Castanea sativa L. present in all samples. Orange honey contained 2.9 to 26.5% Citrus spp. pollen, belonged to Maurizio's Class II, and was characterized by the presence of Brassicaceae, Fabaceae, Olea europea L., Quercus coccifera L. and Rosaceae. In thyme honeys Thymus capitatus Hoffm. &; Link. pollen was secondary or predominant ranging from 18.3 to 69.3%. These honeys belonged to Maurizio's Classes I or II and contained greater than 30 pollen types. Other Lamiaceae, Hypericum spp., Brassicaceae, Fabaceae, Rosaceae, and Cistus spp. pollen types appeared in the greatest number of thyme samples.     

Interdependence of peat and vegetation in a tropical peat swamp forest

The visual uniformity of tropical peat swamp forest masks the considerable variation in forest structure that has evolved in response to differences and changes in peat characteristics over many millennia. Details are presented of forest structure and tree composition of the principal peat swamp forest types in the upper catchment of Sungai Sebangau, Central Kalimantan, Indonesia, in relation to thickness and hydrology of the peat. Consideration is given to data on peat geochemistry and age of peat that provide evidence of the ombrotrophic nature of this vast peatland and its mode of formation. The future sustainability of this ecosystem is predicted from information available on climate change and human impact in this region.     

Methanogenesis and methanogenic pathways in a peat from subarctic permafrost

Few studies have dealt so far with methanogenic pathways and populations in subarctic and arctic soils. We studied the effects of temperature on rates and pathways of CH4 production and on the relative abundance and structure of the archaeal community in a mildly acidic peat from a permafrost region in Siberia (67 degrees N). We monitored the production of CH4 and CO2 over time and measured the consumption of Fe(II), ethanol and volatile fatty acids. All experiments were performed with and without specific inhibitors [2-bromoethanesulfonate (BES) for methanogenesis and CH3F for acetoclastic methanogenesis]. The optimum temperature for methanogenesis was between 26 degrees C and 28 degrees C [4.3 micromol CH4 (g dry weight)(-1) day(-1)], but the activity was high even at 4 degrees C [0.75 micromol CH4 (g dry weight)(-1) day(-1)], constituting 17% of that at 27 degrees C. The population structure of archaea was studied by terminal restriction fragment length polymorphism analysis and remained constant over a wide temperature range. Acetoclastic methanogenesis accounted for about 70% of the total methanogenesis. Most 16S rRNA gene sequences clustered with Methanosarcinales, correlating with the prevalence of acetoclastic methanogenesis. In addition, sequences clustering with Methanobacteriales were recovered. Fe reduction occurred in parallel to methanogenesis. At lower and higher temperatures Fe reduction was not affected by BES. Because butyrate was consumed during methanogenesis and accumulated when methanogenesis was inhibited (BES and CH3F), it is proposed to serve as methanogenic precursor, providing acetate and H2 by syntrophic oxidation. In addition, ethanol and caproate occurred as intermediates. Because of thermodynamic constraints, homoacetogenesis could not compete with hydrogenotrophic methanogenesis.     

Late Pleistocene and Holocene environments of the Southeastern United States from the stratigraphy and pollen content of a peat deposit on the Georgia Coastal Plain

A 5.4 m peat core from the Sandy Run Creek (SRC) valley in the upper Coastal Plain of Georgia shows that before 30 ka the valley had an aggradational sandy floor with shallow swales and low ridges of 1–2 m amplitude suggesting a braided stream pattern and a low water table. The climate from 30–25 ka was cool and dry and the vegetation open grassland with stands of pine and spruce that produced few fires. At ca. 16 ka a warmer, wetter climate caused SRC to meander and incise the valley fill removing some previously deposited sediment at the site of our peat core so that sediments of 13 ka rest directly on sediments deposited at 25 ka. After ca. 13 ka higher groundwater levels initiated vertical accretion of floodplains allowing peat accumulation in shallow depressions across the valley. Pollen from the Younger Dryas period (ca. 13–11 ka) indicates a cool, moist environment of open oak woodland, mesic trees, riparian populations of alder, and reduced levels of pine. By the early to mid Holocene, tupelo and oak dominated over pine indicating wetter conditions, while sand stringers in peat record periodic heavy rains, an elevated water table, and intervals of substantial runoff. Cooling after ca. 4.5 ka brought drier and more variable conditions. Fires increased and southern pine replaced tupelo and oak. The absence of sand stringers in peat younger than 4.5 ka indicates fewer intense rainfall events.