Peat Sediments Research Articles

Decline of the natterjack toad Bufo calamita in Britain: Palaeoecological, documentary and experimental evidence for breeding site acidification

Natterjack toads Bufo calamita have declined sharply at heathland sites in Britain during the 20th century. A significant feature of these habitats is the predominance of oligotrophic and dystrophic ponds on substrates with low buffering capacities. Acid ponds at one site, Woolmer Forest, were classified into two groups: shallow pools dominated by Sphagnum and high concentrations of organic solutes, and larger bodies of water in which pH was primarily influenced by inorganic anions (especially SO 4). Pond pHs responded transiently to episodes of very acid ( pH < 4) rain, but acidity in the larger ponds was probably modulated mainly by mobilisation of sulphur accumulated in sedimentary peat over many decades. Rain was significantly acidified (on average about threefold) after passage through pine canopies, but this effect was not observed after percolation through birch foliage. Two large ponds previously used but deserted by natterjacks within the last 50 years were too acid ( pH < 4.5) in the 1980s to support embryonic and larval development. Evidence from diatom, macrophyte, heavy metal and soot particle analyses of sediment cores from these ponds indicated that recent acidification has occurred as a consequence of atmospheric pollution. The pH of one acidified pond rose rapidly after removal of recent sedimentary peat. The implications of these observations for heathland conservation are discussed.

Palynology and mycology of organic clay balls accompanying mastodon bones—New Brunswick, Canada

Abstract Enigmatic clay balls accompanying a 37000-year-old skeleton of an American mastodon, and clayey nodules adhering to some of the bones, were examined for pollen and spores of plants and spores of fungi. The nodule assemblage of plant palynomorphs is dominated by pollen of Cyperaceae, that of clay ball by pollen of Pinaceae. Both the nodule and the clay ball asemblages of fungi are dominated by spores of Sordariales, which are predominantly dung-dwelling, and which commonly occur in lake and peat sediments. However, the clay ball fungi are relatively more numerous, taxonomically more diverse, and ecologically representative of a wide range of habitats. From palynological and mycological evidence, and the presence of even-sized fragments of wood, we suggest that the organic component of the clay ball is derived from plants consumed by, and contained within, the animal at the time of death.

The Diatom History of an Urban Lake: Summit Lake, Akron, Ohio

ABSTRACT Sedimentary diatoms from a 609 cm core indicated that Summit Lake, Akron, Ohio, originated as a shallow alkaline pool following late Pleistocene glaciation. The lake gradually developed a limnetic zone and became a peat bog. In recent years, the lake has become a slightly alkaline hypertrophic waterbody probably because of increased soil erosion and domestic sewage pollution. One hundred thirty (130) taxa (species and varieties) of diatoms were identified from the sediments of Summit Lake. Species most frequently encountered in the oldest sediments were Fragilaria brevistriata, F. construens, and F. pinnata. Those common in younger peat sediments were Achnanthes exigua, Cyclotella compta, Cymbella diluviana, Fragilaria brevistriata, F. construens, F. pinnata, Mastogloia smithii var. lacustris, and Tabellaria quadrisepta. The most abundant diatoms in recent sediments (since 1800 A.D.) were Asterionella formosa, Cocconeis placentula, Cyclotella meneghiniana, Fragilaria crotonensis, Melosira granula...

Denitrification in Marl and Peat Sediments in the Florida Everglades

The potential for denitrification in marl and peat sediments in the Shark River Slough in the Everglades National Park was determined by the acetylene blockage assay. The influence of nitrate concentration on denitrification rate and N(2)O yield from added nitrate was examined. The effects of added glucose and phosphate and of temperature on the denitrification potential were determined. The sediments readily denitrified added nitrate. N(2)O was released from the sediments both with and without added acetylene. The marl sediments had higher rates than the peat on every date sampled. Denitrification was nitrate limited; however, the yields of N(2)O amounted to only 10 to 34% of the added nitrate when 100 muM nitrate was added. On the basis of measured increases in ammonium concentration, it appears that the balance of added nitrate may be converted to ammonium in the marl sediment. The sediment temperature at the time of sampling greatly influenced the denitrification potential (15-fold rate change) at the marl site, indicating that either the number or the specific activity of the denitrifiers changed in response to temperature fluctuations (9 to 25 degrees C) in the sediment. It is apparent from this study that denitrification in Everglades sediments is not an effective means of removing excess nitrogen which may be introduced as nitrate into the ecosystem with supply water from the South Florida watershed and that sporadic addition of nitrate-rich water may lead to nitrous oxide release from these wetlands.

Palaeogeobotanical evaluation of the Holocene profile from the Řežabinec fish-pond

Stratigraphic, pollen and macroscopic analyses of the Holocene limnic and peat sediments from the Řežabinec fish-pond (southern Bohemia, Czechoslovakia) are presented and evaluated. New information on the sedimentary processes (especially the middle Holocene stratigraphic anomaly), the development of aquatic and mire vegetation, the character of the forest cover and human activity in the Řežabinec area during the Preboreal, Boreal, Subboreal and Subatlantic has been obtained.

An attempt at synthesizing the Holocene biostratigraphy of a «type area» in northern Norway by means of recommended methods for zonation and comparison of biostratigraphical data

The Holocene vegetation history in an area of northern Norway has been investigated by means of 12 pollen-analysed sections ; 11 of them from peat sediments. Biostratigraphical zonation of the individual pollen diagrams, and comparison between pairs of them have been carried out by numerical methods of the IGCP-158-b research programme. Generally, the zonation programme have adequate results. Zonation of the total pollen taxon assemblage including the peatforming taxa - and zonation of the regional pollen assemblage (trees), gave rather similar results. However, when studying man’s impact on vegetation, it might prove useful to exclude all peatforming taxa before running the zonation programme. The comparison programme proved not to give adequate treatment of this material, which is characterized by spectra with a high degree of similarity throughout the Holocene.

Late glacial finds ofPinus cembra L. in the Lubovnianská kotlina Basin

During the palaeobotanical investigation of the Spisska kotlina Basin and the neighbouring areas, seeds ofPinus cembra L. were found in limonitized concretions and peat sediment of the Sivarňa mire situated near the village of Vysne Ružbachy (east of the High Tatra). The presence of this tree species was also confirmed by pollen analysis. It is the first find of fossil seeds dating from the Late glacial in Czechoslovakia.

Vegetation near Lake Poukawa prior to the Taupo Eruption

Abstract Palynological analyses of peat and lake sediments from Lake Poukawa show that dense podocarp/hardwood forest was present throughout the 2,000-year period preceding the Taupo eruption of c. 1,820 years ago. The stable pollen record and absence of charcoal are interpreted as evidence that there was no human occupation of this area of Hawkes Bay before the main period of deforestation beginning c. 1,000 years ago.

Late Quaternary Vegetation History of the Nyika Plateau, Malawi

Pollen analysis of peat sediments found in valley-head 'dambos' of the Nyika Plateau, Malawi, has yielded a vegetation history spanning the last 5000 years as indicated by radiocarbon dating. The contemporary vegetation pattern of small patches of montane forest in a sea of montane grassland is shown to have been in existence for at least as far as the peat record extends and indications from a radiocarbon dated organic clay further suggest its prominence as far back as 12,000 years B.P. Assertions that the plateau was mainly forested as recently as 1000 years ago are refuted by the palynological evidence. The somewhat surprising conclusion of relative environmental stability during the Holocene in this part of Africa is supported by similar evidence from elsewhere within the region.

Postglacial vegetational history of Tonquin Pass, British Columbia

A pollen and macrofossil study of peat sediments in Tonquin Pass, British Columbia provides the oldest dated record of vegetational and climatic changes in the middle Canadian Rockies. Paleoecological interpretation of these events dated by tephrochronology and radiocarbon dating is facilitated by comparisons with other regional pollen profiles.Late Wisconsin ice receded from Tonquin Pass prior to 10 000 years BP. By 9700 years BP a Pinus contorta forest with an understory dominated by ferns had colonized the area. The climate of this period was cool and moist. Following this interval was a brief episode (9000–8040 years BP) of haploxylon pine dominance during which the climate became colder. A long warm period beginning by 8040 years BP was characterized by desiccation of local meadows and fens and invasions of these areas by trees, principally Picea. Dated fossil Picea and Abies logs from alpine bogs within Jasper National Park document that timberlines had advanced beyond present limits by 8770 years BP. These data indicate a considerable lag in the registration of this interval in the Tonquin record.During the last 4300 years the retreat of trees from meadows and increases in the representation of several alpine taxa indicate that generally moist and cool conditions have prevailed. Evidence for Holocene timberline fluctuations in the Jasper area suggests an overall lowering in timberline elevation and further cooling since 1700 years BP.

Late Holocene Glacier Fluctuations and Vegetation Changes at Maktak Fiord, Baffin Island, N.W.T., Canada

Maktak Glacier is a major distributary of the Penny Ice Cap and thus changes in its frontal position reflect variations in the mass balance of the ice cap. The Neoglacial terminal moraine of this glacier consists of a 20-m thick sedimentary sequence of till, overlain by up to 18 m of sands and gravels which contain a 1-m thick peat bed. These sediments were deformed by glacier pushing and are overlain by a younger till. The basal till and the overlying sands and gravels beneath the peat were deposited during the retreat from the Cockburn Stade. The site was deglaciated at some time after 5000 to 6000 BP. Peat on a terrace surface was studied using absolute pollen analyses, and clustering routines to distinguish pollen zones. The start of peat growth at 2500 BP (synchronous with such events elsewhere) is attributable to altered permafrost levels and/or increases in precipitation/ evaporation budgets, producing wetter conditions locally. The vegetational history began with a moist willow episode, which was followed by a dominantly grass community as local conditions became drier. The initial rapid growth of peat became progressively slower throughout the profile, until by 1500 BP the slow accumulation of humified peat was overwhelmed by windblown sand which inhibited further growth. A subsequent Maktak Glacier advance deposited sands and gravels over the peat bed. Between 350 and 65 BP, glacial pushing and overriding of the terrace and peat sediments occurred. Exotic tree pollens were identified in the sediments; their changing frequencies may provide some tentative measure of changing airflows into the High Arctic.

A piston corer for peat1

The construction and operation of a corer capable of recovering uncontaminated and uncompressed samples of peat and other soft sediments from precisely predetermined depths is described.

Petrology of Some Holocene Peat Sediments from the Okefenokee Swamp-Marsh Complex of Southern Georgia

Ten or more samples of surface peat were obtained from each of six peat-forming environments in the Okefenokee swamp-marsh complex of southern Georgia. These peat-forming environments were chosen for study because they were found from core studies to have been the most important peat producers throughout much of the history of peat formation in the swamp. The peat samples were dehydrated in alcohol, embedded in paraffin (using the methods of Cohen and Spackman, 1972), and sectioned (to 15 µ) with a sliding microtome. The microscopic features found to be most useful in characterizing the peats and relating them to their original depositional and vegetational environments were (1) their color (at 30×); (2) the ratio of framework to matrix; (3) the ratio of nonsedimentary to sedimentary constituents; (4) the proportions of remnants of plants assignable to particular plant species; and (5) the percentages of various accessory ingredients, such as fungal remains, fecal pellets, diatoms, insect parts, sponge spicules, quartz, and charcoal. The peat-forming environments investigated were (1) the Nymphaea environment (open-water marshes dominated by floating aquatic plants); (2) the Carex , Panicum , and Woodwardia environments (glades or island fringes dominated by emergent aquatic plants); and (3) Cyrilla and Taxodium environments (tree islands and swamps). The peat sediments deposited in each of these regions were found to have distinctively different micropetrographic characteristics. Aside from the qualitative and quantitative data collected for the purpose of defining the peat types, data were also collected in a form which could be used to determine the most likely eventual coal compositions of the peats. The herbaceous peats were found to have low percentages of pre-resinites (cell fillings and secretions), pre-sclerotinites (fungal remains), and fusinite (charcoal), and high percentages of pre-micrinites (fine granular debris). On the other hand, peats derived from tree vegetation had higher percentages of pre-resinites, pre-sclerotinites, and fusinites, and had relatively smaller amounts of pre-micrinitic materials. The former would probably result in a massive (unlaminated) dull coal, and the latter would probably become a somewhat brighter laminated type.

Effect of Late Pleistocene Karst Topography on Holocene Sedimentation and Biota, Lower Florida Keys

Detailed mapping of bedrock topography on Bahia Honda and Big Pine Keys has revealed a buried karst topography not previously documented in the lower Florida Keys. This topography, developed during lowered sea level of the Pleistocene, strongly controls Holocene sediment thickness and present biotic distribution. Circular to oval sinkholes, which are up to 75 m or more in diameter and over 4 m deep, are usually completely filled with peat and carbonate sediment. Sinkholes are well developed on both the Miami Limestone (oolitic facies) and the Key Largo Limestone (both late Pleistocene in age). Thick sediment in buried sinkholes in more than a few inches of water favors the growth of thick patches of turtle grass (Thalassia testudinum). Shallower water and supratidally located sinkholes (that is, those partly or wholly surrounded by subaerially exposed bedrock) are generally marked by thick growths of either red or black mangroves (Rhizophora mangle and Avicennia nitida). These distinct, nearly circular vegetation patterns are extremely abundant in the study area, as shown by aerial photographs which suggest that Bahia Honda and Big Pine Keys are “riddled” with sinkholes.

A STUDY ON POLLEN DISPERSAL AND SEDIMENTATION IN THE WESTERN PART OF THE NETHERLANDS

SUMMARY The interpretation of palynological data into a history of the plant communities in a region requires (1) the estimation of the pollen density in the samples, (2) the knowledge of the relative representation rates of the vegetation elements in the pollen spectra and (3) a careful distinction between air-borne and water-borne pollen because of their different recording values. In the present article, a method is described for pollen density determination which is convenient when cores have to be analysed consisting of peat, gyttja and clastic sediments. This method involves the addition of a foreign pollen. Examples are given of the variation which may occur in the pollen density of sediments in a horizontal series of samples. In three cores the pollen densities were determined and the use of this additional information for the interpretation of the analysis data is demonstrated. In a number of nature reserves a comparison was made between the composition of the local stand of vegetation and the pollen sedimentation. To this purpose moss samples were analysed. The representation of the plant communities was generally found to be fair. The dispersal of water-borne pollen was studied by a comparison of the regional vegetation types with the pollen precipitated on river banks and tidal flats; there was also made a series of analyses of the pollen content of the water, which shows that the seasonal variations are so small that the pollen which is precipitated from the water in the regions investigated is not representative for the regional vegetation type. The pollen which is deposited in such conditions may originate from three different sources: (1) the local or regional stand of vegetation, (2) forests or other plant communities in remote upstream areas and (3) peat or gyttja layers or other pollen containing deposits which are eroded by the water currents. A number of examples of these dispersal mechanisms is described in this article. In a few cases it is demonstrated how the determination of pollen density may contribute to the solution of the problem, in which proportion these three dispersal mechanisms have been responsable for the presence of the pollen in the sediment under investigation.

Recent Algal Mats of a Persian Gulf Lagoon

Extensive laminated mats of algae are forming on the protected intertidal and supratidal flats of a highly saline lagoon, the Khor al Bazam, Abu Dhabi, southwest Persian Gulf. At the east end of the lagoon, the largest algal flat parallels the coast for 42 kilometers, and to the west another smaller one parallels the coast for nine kilometers. These flats, part of the seaward edge of a prograding coastal flat, have an average width of approximately two kilometers and a thickness of at least thirty centimeters. In some areas they extend landward in the subsurface for more than two kilometers, beneath a thin cover of evaporites and wind blown and storm washover sediments. Smaller flats occur in the shelter of islands, headlands, and swash bars. The larger algal flats are divided on the basis of surface morphology, into four geographical belts. From the high-water mark seaward these are: (1) Flat zone--firm, smooth algal mat, with no topographic relief, overlying quartz-rich carbonate sand and evaporites; (2) Crinkle zone--leathery algal skin forming a blistered surface over gypsum and carbonate mush; (3) Polygonal zone--algal mat separated into desiccation polygons a few centimeters to two meters in diameter, which cover laminated algal peat; carbonate sand and mud fills the cracks between the polygons. (4) Cinder zone--a warty black algal surface, the color and size of the raised bumps resembling a weathered volcanic cinder layer. These bumps, shaped like small pustules two to three centimeters in diameter, cap an unlaminated algal and sediment peat. The algal growth and structures appear to be determined by the frequency and duration of subaerial exposure and the salinity of the tidal waters; they are only related to wave energy when limited by wave and tidal scour at the edge of the Cinder zone and along ebb channels.

Some aeropalynological remarks and conclusions on the South Carpathian Mountains (Rumania)

Two methods of research are described: 1. ( 1) Spore and pollen analysis at every hundred meters of the moss patches from the beech to the alpine zones (900–2,484 m altitude). At each level the actual structure of the vegetation has been established. 2. ( 2) Daily aeropalynological trapping of pollen in the alpine and subalpine zones between March 29 and August 21, 1965. In the first case, as long as the samples were collected within the forest, the pollen spectra were found to be in conformity with the surrounding vegetation. However, in the alpine zone pollen from lower zones becomes frequent, depending on the prevailing aerial currents in the studied mountain massif. In the second case, the following phenomena were established: periodicity in pollen productivity; reflotation owing to air turbulence; the action of southwesterly and southeasterly winds, which carried some alien pollen species before the local flowering period, and the action of northwesterly winds carrying generally the same pollen after the local flowering period. The importance of the findings for the understanding of pollen spectra from peat sediments is discussed.

A STUDY OF ORGANIC SOIL HORIZONS USING ELECTROPHORETIC TECHNIQUES

SummarySaturated sodium‐pyrophosphate extracts were obtained from samples of Sphagnum‐moss peat, sedimentary peat, fibrous peat, disintegrated peat, and muck and were subjected to electrophoretic separation and analysed for organic matter, polysaccharides, and coloured material. The resulting patterns indicated a marked difference between the muck samples and the peat samples. The high exchange‐capacity values obtained for muck samples were associated with the amount of highly charged material rather than with an increase in the charge density of this material. The muck and the fibrous‐peat samples appeared to be end members in a disintegration and oxidation sequence involving many intermediate stages.

Peat Deposits of the State of Washington

AbstractThis paper emphasizes (1) the structure of the entire peat deposit down to clay, sand, or gravel, (2) the plants whose remains have formed the various kinds of peat, (3) the origin of the depressions in which the deposits have developed, and (4) the physical and chemical properties of the peat.The 325 deposits which were investigated comprise over 50,000 acres and vary in depth from 3 to 63 feet. The kinds of peat in the order in which they commonly occur from top to bottom and the plants from whose remains they were formed are (1) moss peat from various species of Sphagnum, (2) fibrous peat mostly from sedges, (3) woody peat from logs, twigs and leaves, and (4) sedimentary peat frommicroscopic plants. Moss peat is absent in many deposits. The asociated mineral materials are mostly marl, diatomite (diatomaceous earth), and volcanic ash.The depressions in which the deposits have developed were formed mainly by the activities of ice, water, or wind. A summary of the ranges and averages of pH, field moisture, ash, chemical composition and replaceable bases is tabulated. The types of soil on the deposits are Greenwood, Mukilteo, Spalding, Rifle, Tanwax, and Salt Marsh.Data on chemical composition of the peat, including replaceable bases are given.

Mollusks of Sodon Lake, Oakland County, Michigan. II. The Winter Occurrence of Certain Species

Although the authors of this paper are primarily plant ecologists, they developed an interest in the mollusks of Sodon Lake through efforts to correlate the occurrence of fossil shells in the marl and peat sediments with the lateand post-glacial history of the area as worked out by pollen analysis (Cain, Segadas-Vianna, and Bunt, '50). The above study of the fossil shells was carried out from late fall and winter to early summer and was accompanied by an effort to ascertain the nature of the contemporary molluscan fauna which had not been studied previously.