Subsurface Peat Research Articles

Control of Methane Metabolism in a Forested Northern Wetland, New York State, by Aeration, Substrates, and Peat Size Fractions

Although many northern peat-forming wetlands (peatlands) are a suitable habitat for anaerobic CH 4 -producing bacteria (methanogens), net CH 4 fluxes are typically low in forested systems. We examined whether soil factors (aeration, substrate availability, peat size fractions) constrained net CH 4 production in peat from a Sphagnum -moss dominated, forested peatland in central New York State. The mean rate of net CH 4 production measured at 24° C was 79 nmol g -1 d -1 , and the mean rate of CO 2 production (respiration) was 5.7 w mol g -1 d -1 , in surface (0 to 10 cm) and subsurface (30 to 40 cm) peat. Saturated peat (900% water content) exposed to oxic conditions for 2 days or 14 days showed no net CH 4 production when subsequently exposed to anoxic conditions. Rates of CO 2 production, measured concomitantly, were essentially the same under oxic and anoxic conditions, and net CH 4 consumption under oxic conditions was barely affected by short-term exposure to anoxic conditions. Therefore, methanogens were particularly sensitive to aeration. Net CH 4 production in whole peat increased within hours of adding either acetate, glucose, or ethanol, substrates that methanogens can convert directly or indirectly into CH 4 , indicating that availability of these substrate might limit net CH 4 production in situ. In longer incubations of 30 days, only ethanol addition stimulated a large increase in net CH 4 production, suggesting growth in the population of methanogens when ethanol was available. We fractionated peat into size fractions and the largest sized fraction (> 1.19 mm), composed mostly of roots, showed the greatest net CH 4 production, although net CH 4 production in smaller fractions showed the largest response to ethanol addition. The circumstantial evidence presented here, that ethanol coming from plant roots supports net CH 4 production in forested sites, merits more research.

Heuristic numerical and analytical models of the hydrologic controls over vertical solute transport in a domed peat bog, Jura Mountains, Switzerland

AbstractWe report the results of numerical and analytical simulations to test the hypothesis that downward vertical flow of porewater from the crests of domed alpine and kettle bogs controls vertical porewater distributions of major solutes such as Ca and Mg. The domed Etang de la Gruère bog (EGr), Switzerland, characterized by a vertical downward gradient of 0·04 and stratified layers of peat, is chosen as a field site for the model calibration and evaluation. The middle 4‐m section of the 6·5 m thick bog peat is heavily humified and has a hydraulic conductivity of ∼10−5·6 cm s−1. Above and below, peat is less humified with a hydraulic conductivity of ∼10−3 cm s−1. Heuristic finite difference simulations, using Visual MODFLOW, of the bog hydraulics show that the higher conductivity peat at the bog base is critical to create the observed deep, local flow cells that substantively recharge porewater.Model results and Peclet number calculations show that before ∼7000 14C yr BP diffusion of solutes from underlying mineral soils controlled the vertical distribution of porewater chemistry. From 7000 to ∼1250 14C BP the porewater chemistry was probably controlled by both upward diffusion and downward advection, and after ∼1250 14C yr BP porewater chemistry was probably controlled by downward advection. Concentrations of conservative major solutes in the porewaters of alpine, ombrotrophic bogs are the net effect of both downward vertical porewater movement and upward vertical diffusion, the magnitudes of which are delicately poised to the configuration of the bog water table over time and subsurface peat stratigraphy. Copyright © 2002 John Wiley & Sons, Ltd.

Methane Oxidation, Production, and Emission at Contrasting Sites in a Boreal Bog

Boreal peatlands, a major source of atmospheric CH4, are characterized by a rapidly fluctuating water table position and meter-scale variations in relief. Regional and ecosystem-based studies show that water table position generally controls CH4 emission from boreal peatlands by influencing the relative extent of the zones of CH4 oxidation and production within the peat profile. We used a combined field and laboratory study to assess the influence of local hydrology on the short-term dynamics of CH4 production, oxidation, and emission from sites in an Alaskan boreal peatland that were characterized by temporarily (site LB1A) and permanently (LB2) water-saturated subsurface peat during the thaw season. The two sites contrasted sharply with respect to the dynamics of CH4 cycling. Site LB1A, which showed low CH4

Controls on Microbial Production of Methane and Carbon Dioxide in Three Sphagnum-Dominated Peatland Ecosystems as Revealed by a Reciprocal Field Peat Transplant Experiment

We examined controls on mineralization of carbon to methane (CH4) and carbon dioxide (CO2) in Sphagnum (moss)-dominated peatland ecosystems by transplanting surface (5 cm deep) and subsurface (40 cm deep) peat samples reciprocally among three sites for periods ranging from 4 to 25 months. The sites were Big Run Bog in West Virginia, USA, Bog Lake Bog in Minnesota, USA, and Bog 307 in Ontario, Canada. Immediately upon retrieval, we incubated the peat samples in the laboratory at 12 and 22°C under both anoxic and oxic conditions to estimate rates of carbon mineralization. Transplanting affected surface peat more than subsurface peat. Peat incubated within Bog Lake Bog in Minnesota had the highest rates of CH4 production, regardless of origin, whereas transplanting did not affect rates of CO2 production measured concomitantly. Peat that originated in Big Run Bog in West Virginia generally maintained higher rates of CH4 production and CO2 production than peat from the other two sites after incubation in the field. The temperature dependence (Q 10) of CH4 production and CO2 production varied among transplant sites, but not among peat origins, suggesting physiological adaptations of microbial communities to local environmental conditions. Differences in organic matter quality of the peat, particularly lignin chemistry, helped explain the results: (a) CH4 production correlated with fresher lignin derived from Carex sedges, and (b) CO2 production correlated with woody lignin. We concluded that, although both site conditions (climate, nutrient status, and microbial communities) and organic matter quality influence carbon mineralization in peat, interactive effects occur and may differ depending on peat temperature. Moreover, CH4 production and CO2 production respond differently to environmental regulators.

Changes in the δ34S ratio of pore-water sulfate in incubated Sphagnum peat

Abstract Sulfur transformations in freshwater peat were studied using contrasting stable isotope signatures of atmospheric input (high δ34S) and Sphagnum peat substrate (low δ34S). Wet subsurface peat samples from the Lehstenbach watershed, Fichtelgebirge, Germany were incubated anaerobically at 5 and 15°C. Pore-water sulfate was augmented with natural precipitation at the onset of the experiments. Sulfate concentrations and δ34S ratios of residual pore water were measured in 1-day intervals (9 days) and 1-week intervals (7 weeks) at 15°C, and in 1-week intervals (7 weeks) at 5°C. Initially, SO42− concentrations decreased (by 50 to 85%) and δ34S ratios increased (by as much as 16‰) at both temperatures due to bacterially-mediated dissimilatory sulfate reduction. At the higher temperature (15°C), the S isotope effect (Δ δ34S) was higher than at the lower temperature (5°C). On day 4 (at 15°C) and day 29 (at 5°C), the δ34S ratio of pore-water sulfate started to decrease by as much as 20‰. The changing S isot...

Turnover of Detrital Organic Carbon in a Nutrient‐Impacted Everglades Marsh

AbstractPhosphorus loading to the Everglades from nearby agricultural areas has become a major concern, and is considered to be a significant factor in the encroachment of cattail (Typha domingensis Pers.) and other rapidly growing vegetation into endemic sawgrass (Cladium jamaicense Crantz) marsh. The objectives of this research were to evaluate the variability in turnover of organic C in plant and soil detrital pools along a P enrichment gradient in an Everglades marsh and to identify substrate characteristics and environmental factors controlling C turnover. Potential rates of C mineralization in plant litter and peat were determined by measuring aerobic and anaerobic microbial respiration under controlled conditions in laboratory incubations. Potential C mineralization decreased with depth and, consequently, substrate age, in the plant‐soil profile. Within individual detrital pools [standing dead plant material, soil litter layer, surface peat (0–10 cm depth) and subsurface peat (10–30 cm depth)], potential C mineralization decreased down gradient from the source of nutrient loading to WCA‐2A. Overall, 91% of the variability in aerobic C mineralization in peat and plant litter was accounted for by substrate P concentration and lignocellulose composition. Anaerobic C mineralization rates were consistently about one‐third of aerobic rates. Results indicated that organic C turnover in detrital pools in WCA‐2A is significantly affected by accelerated P loading, but is also controlled by O2 availability and substrate C quality.

Methane emissions from wetlands, southern Hudson Bay lowland

Methane emissions were measured by a static chamber technique at 39 sites along a transect from the James Bay coast at the southeastern tip of Hudson Bay to Kinosheo Lake, northwest of Moosonee, Ontario, Canada. These sites represented five major wetland ecosystems along a successional gradient from the coast inland. Measurements were made at ≈ 10‐day intervals from early June to mid‐August, and once in mid‐September and mid‐October 1990. Seasonal CH4 fluxes were small (<2 g m−2) at the recently emerged coastal marsh, coastal fen, tamarack fen, and interior fen ecosystems, except where there were shallow ponds and pools, which emitted 2–5 g CH4 m−2. At the more complex bog ecosystem locations, CH4 fluxes were small (0.3–2.0 g m−2) from hummock/hollow microtopography in the raised bogs and from the forested margin. The largest CH4 fluxes were recorded from the degrading peat sections forming shallow pools and the moss/sedge mats which were always close to saturation (1.8–16.6 g m−2). A deeper (1‐m water depth) pool emitted less CH4 (1.4 g m−2). In terms of ecological succession along the transect, covering emergence over ≈ 4000 yr, CH4 emission rates increase from marsh to fen and bog, primarily through the development of peat degradation and the formation of moss/sedge lawns and pools. There were very weak statistical relationships at each site between the daily CH4 flux and peat temperature and water table. However, there was a significant (r2 = 0.44, p < 0.001) correlation between the seasonal CH4 flux and the mean position of the water table over the complete range of sites, emphasizing the overall importance of hydrology in determining CH4 flux. Laboratory incubation experiments were conducted to determine the capacity of the surface (0–20 cm depth) peat samples to produce CH4 anaerobically and consume CH4 aerobically. They revealed that many samples exhibited high CH4 consumption rates, suggesting that although CH4 production in the subsurface peat is high, CH4 emissions from these wetlands to the atmosphere are limited to a large extent by CH4 oxidation in the surface layers of the peat. Trophic status of the peat appeared to have little influence on emission rates, with the highest fluxes in the most acid (pH < 3.5) samples.

Morphology and causes of recent peat slides on Skerry Hill, Co. Antrim, Northern Ireland

AbstractTwo shallow translational slides occurred in blanket peat on Skerry Hill, Co. Antrim, in November 1991 at sites adjacent to slides activated c. 25 years ago. Heavy rainfall, degraded drainage ditches and slope morphology are considered to have been important factors contributing to peat instability. The failure planes are located close to the peat base, at the boundary between less compact fibrous peat above and more compact humified peat below. The preservation of large blocks and rafts of intact peat and the limited amount of liquefied peat in the debris tongues is thought to reflect the degree of peat humification. There is also some evidence to suggest that the peat was probably undersaturated at the time of failure and this may have assisted preservation of intact peat blocks. Tension cracks, resulting from either short‐term desiccation or long‐term slow mass movement, are thought to have facilitated the rapid transfer of heavy rain to the subsurface peat, causing high pore‐water pressures and lubrication of the failure planes. Vegetation recolonization will probably follow a pattern similar to that observed on the adjacent earlier slides.

The behaviour of major and trace elements in complete vertical peat profiles from three Sphagnum bogs

The distribution of major elements (Al, Ca, K, Mg, Na) in peat profiles from two contrasting ombrotrophic Sphagnum bogs is interpreted in respect to the abundance and mineralogical composition of ash, atmospheric deposition, plant bioaccumulation and leaching. High concentrations of Ca are found in the minerotrophic peats from a continental bog underlain by calcareous sediments (Luther bog, Ontario). Aluminum is more abundant in the minerotrophic peats from a coastal bog in a siliceous terrain (Barrington bog, Nova Scotia). The peats at the coastal site contain an average of 3 times as much Na and Mg as the peats from the continental bog because of sea spray. Potassium is highly enriched in the surface peats at both sites because of plant bioaccumulation. The behaviour of trace metals (Cr, Cu, Fe, Mn, Ni, Pb, U, V, Zn) in peat profiles is explained in terms of the abundance and distribution of mineral matter, plant bioaccumulation, the response of metals to acidic, anaerobic conditions, and anthropogenic atmospheric deposition. The distribution of Ni, V and Cr in the peats from a third bog (Galbraith Bog, Ontario) follows that of mineral-matter content, and the metals are highly correlated with ash. Relative to the mean composition of the underlying mineral sediments (clays) collected at 30 other sites, the peats are neither significantly (> 2 times) enriched nor depleted in Ni, V and Cr. Manganese is strongly enriched in surface and near-surface peat layers because of plant bioaccumulation. In contrast, Fe and Mn are relatively depleted in subsurface peats due to their enhanced solubilities in acidic, anaerobic waters. The opposite is true for Cu and U which accumulate in peats because of their diminished solubilities in anaerobic environments. Enrichments of Zn and Pb also occur, but these are restricted to surface peats, and are due to anthropogenic metal deposition.

Chemical properties of subsurface peats and their decomposition kinetics under field conditions

Abstract Samples of high moor peat consisting of Sphagnum moss, high moor peat consisting of Sphagnum moss and Carex middendorffii, and low moor peat consisting of Carex spp. taken from the subsurface layers of a non-cultivated site or cultivated fields were analyzed for the content in inorganic and organic constituents, and their decomposability in soil was examined under field conditions in upland and wetland rice fields. For comparison with the peat samples, rice and wheat straw and compost were also examined. Decomposition rate constants (k) of peats mixed with soil for a single compartment exponential decay model, Y t = C 0exp(− kt), ranged from 0.0032 to 0.0096 (month−1), equivalent to 3.7-11% carbon loss after 1 year, and the decomposition was enhanced by mixing with soil. Changes in the amounts of nitrogen of the peat materials were also fitted to the model and gave rate constants (k) of 0.0015-0.0078, equivalent to 1.8-9.0% loss after 1 year, for samples mixed with soil. The decomposition of rice...

BULK DENSITY OF SURFACE SOILS AND PEAT IN THE NORTH CENTRAL UNITED STATES

Relationships between bulk density (BD) and loss on ignition (LOI) for forest floor, shallow mineral soil (0–25 cm depth), and peat were described by exponential functions. The data were collected in forests across the North Central US. For forest floor, predicted BD, BDp = 0.073 + 2.369 exp(− 0.073 LOI), R2 = 0.75, (BDp in Mg m−3 and LOI in percent dry wt), and for surface mineral soil, BDp = 0.669 + 0.941 exp(− 0.240 LOI), R2 = 0.95. For peat, BDp = 0.043X + 4.258 exp(− 0.047 LOI), R2 = 0.89, where X is a dummy variable with a value of 0 for surface peat (0–25 cm depth) and 1 for subsurface peat (25–175 cm). Key words: Bulk density, loss-on-ignition

FRESHWATER DIATOM ASSEMBLAGES AND ECOLOGY/PALAEOECOLOGY OF THE OKEFENOKEE SWAMP/MARSH COMPLEX, SOUTHERN GEORGIA, U.S.A.

Surface and subsurface peats of the Okefenokee Swamp in the southeastern United States contain low diversity diatom assemblages, composed largely of forms typical of peat-forming environments. Multivariate techniques, utilizing the algorithms EXTENDED CABFAC and FUZZY QMODEL (factor/cluster analyses), recognized five major diatom assemblages in the surface peats and the distribution of these correlates with surface flow patterns and hydrological input from the uplands. Streamflow regulates nutrient flux, and so it appears that the major control on diatom communities in the Okefenokee Swamp is local variation in trophic status. Stratigraphical studies reveal a recent history marked by alternating wet and dry conditions, with vegetational and diatom floral succession evident in some regions and relative ecological stability elsewhere. Minor ecological changes associated with increased human activity in the region, beginning late in the nineteenth century, are reflected by changes in the diatom communities. The construction of canals and logging trails provided increased hydrological exchange in previously hydrologically isolated areas, allowing an increase in nutrient input. Certain diatoms, most notably Melosira nygaardii, responded to enhanced flow conditions by colonizing some of these regions. Two new diatom species are proposed: Anomoeoneis paludigena sp. nov. and Pinnularia pogoii sp. nov.

Topographic Fluctuations Across a Spring Fen and Raised Bog in the Lost River Peatland, Northern Minnesota

(1) A topographic survey was conducted with both laser and electronic levels across a spring fen, a raised bog and the water track (fen) between them, in the Lost River Peatland of northern Minnesota. (2) The survey demonstrated that the spring fen consisted of a peat mound whose slopes were steeper than that of the bog. (3) Three successive surveys in 1982 and 1983 showed altitudinal changes in benchmarks fixed in trees relative to a base level on a power-line pylon located in the water track. Nearly all benchmarks rose, with the greatest rises occurring near the centres of the raised bog (11 cm) and spring fen (6 cm) in contrast to very slight rises across the water track. (4) The most likely explanation for this altitudinal change is a swelling of the sub-surface peat in response to artesian fluid pressure generated by regional hydraulic gradients. (5) Very precise determinations of altitude are thus possible with a laser or electronic level on an unstable peat substrate, providing great care is taken in surveying techniques.

Holocene sedimentation of a wave-dominated barrierisland shoreline: Cape Lookout, North Carolina

The sedimentary record of 130 km of microtidal (0.9 m tidal range) high wave energy (1.5 m average wave height) barrier island shoreline of the Cape Lookout cuspate foreland has been evaluated through examination of 3136 m of subsurface samples from closely spaced drill holes. Holocene sedimentation and coastal evolution has been a function of five major depositional processes: (1) eustatic sea-level rise and barrier-shoreline transgression; (2) lateral tidal inlet migration and reworking of barrier island deposits; (3) shoreface sedimentation and local barrier progradation; (4) storm washover deposition with infilling of shallow lagoons; and (5) flood-tidal delta sedimentation in back-barrier environments. Twenty-five radiocarbon dates of subsurface peat and shell material from the Cape Lookout area are the basis for a late Holocene sea-level curve. From 9000 to 4000 B.P. eustatic sea level rose rapidly, resulting in landward migration of both barrier limbs of the cuspate foreland. A decline in the rate of sea-level rise since 4000 B.P. resulted in relative shoreline stabilization and deposition of contrasting coastal sedimentary sequences. The higher energy, storm-dominated northeast barrier limb (Core and Portsmouth Banks) has migrated landward producing a transgressive sequence of coarse-grained, horizontally bedded washover sands overlying burrowed to laminated back-barrier and lagoonal silty sands. Locally, ephemeral tidal inlets have reworked the transgressive barrier sequence depositing fining-upward spit platform and channel-fill sequences of cross-bedded, pebble gravel to fine sand and shell. Shoreface sedimentation along a portion of the lower energy, northwest barrier limb (Bogue Banks) has resulted in shoreline progradation and deposition of a coarsening-up sequence of burrowed to cross-bedded and laminated, fine-grained shoreface and foreshore sands. In contrast, the adjacent barrier island (Shackleford Banks) consists almost totally of inlet-fill sediments deposited by lateral tidal inlet migration. Holocene sediments in the shallow lagoons behind the barriers are 5–8 m thick fining-up sequences of interbedded burrowed, rooted and laminated flood-tidal delta, salt marsh, and washover sands, silts and clays. While barrier island sequences are generally 10 m in thickness, inlet-fill sequences may be as much as 25 m thick and comprise an average of 35% of the Holocene sedimentary deposits. Tidal inlet-fill, back-barrier (including flood-tidal delta) and shoreface deposits are the most highly preservable facies in the wave-dominated barrier-shoreline setting. In the Cape Lookout cuspate foreland, these three facies account for over 80% of the sedimentary deposits preserved beneath the barriers. Foreshore, spit platform and overwash facies account for the remaining 20%.

NONSYMBIOTIC AND SYMBIOTIC NITROGEN FIXATION IN A WEAKLY MINEROTROPHIC PEATLAND

The acetylene reduction assay was used to measure nonsymbiotic and symbiotic nitrogen fixation in a weakly minerotrophic peatland throughout the ice‐free season. Nonsymbiotic nitrogen fixation was found in surface materials and subsurface peat. In surface materials, nitrogenase activity measured in the field contributed about 0.6 kg N ha‐1 yr‐1, was closely associated with Sphagnum, but was not correlated with temperature between 12 and 27 C. No cyanobacteria were found in association with Sphagnum. In subsurface peat, nitrogenase activity measured in situ contributed no more than 0.4 kg N ha‐1 yr‐1 and was closely correlated with temperature between 7 and 21 C. There were uncertainites in these measurements due to presence of ethylene oxidizing activity and a long time lag. Symbiotic nitrogen fixation was found only in actinomycete‐induced root nodules of Myrica gale L. Legumes were absent and the few lichens present lacked nitrogenase activity. Based on acetylene reduction assays, Myrica gale fixed about 35 kg N ha‐1 yr‐1. Nitrogenase activity in Myrica gale showed a strong seasonal pattern which varied little during three consecutive years even though water levels varied substantially. Nitrogen input to the peatland from nonsymbiotic nitrogen fixation was only 15% the amount contributed by bulk precipitation. Symbiotic fixation, in contrast, contributed approximately six times the amount in bulk precipitation.

Nonsymbiotic and Symbiotic Nitrogen Fixation in a Weakly Minerotrophic Peatland

The acetylene reduction assay was used to measure nonsymbiotic and symbiotic nitrogen fixation in a weakly minerotrophic peatland throughout the ice-free season. Nonsymbiotic nitrogen fixation was found in surface materials and subsurface peat. In surface materials, nitrogenase activity measured in the field contributed about 0.6 kg N ha-1 yr-1, was closely associated with Sphagnum, but was not correlated with temperature between 12 and 27 C. No cyanobacteria were found in association with Sphagnum. In subsurface peat, nitrogenase activity measured in situ contributed no more than 0.4 kg N ha-1 yr-1 and was closely correlated with temperature between 7 and 21 C. There were uncertainites in these measurements due to presence of ethylene oxidizing activity and a long time lag. Symbiotic nitrogen fixation was found only in actinomycete-induced root nodules of Myrica gale L. Legumes were absent and the few lichens present lacked nitrogenase activity. Based on acetylene reduction assays, Myrica gale fixed about 35 kg N ha-1 yr-1. Nitrogenase activity in Myrica gale showed a strong seasonal pattern which varied little during three consecutive years even though water levels varied substantially. Nitrogen input to the peatland from nonsymbiotic nitrogen fixation was only 15% the amount contributed by bulk precipitation. Symbiotic fixation, in contrast, contributed approximately six times the amount in bulk precipitation.

Hydrocarbon Geochemistry in Surface Sediments of Alaskan Outer Continental Shelf: Part 2. Distribution of Hydrocarbon Gases

The distribution of C1 to C4 hydrocarbon gases in surficial sediments from the Alaskan continental shelf was determined as part of a regional environmental survey sponsored by National Oceanic and Atmospheric Administration and Bureau of Land Management (NOAA/BLM). Methane, ethane, ethene, propane, propene, n-butane and iso-butane were observed in low concentrations (0.1-10 ppb, as weight gas to dry weight sediment) in nearly all of the 190 sediment samples examined, with methane exceeding C2 to C4 hydrocarbons in abundance by about a factor of 10. No gasoline range (C5 to C8) hydrocarbons were detected above blank levels. Ethene was found generally to be more abundant than ethane, while propane was slightl more abundant than propene--the correlation between these hydrocarbons suggests a common, possibly biogenic, origin. Sediments from Norton Sound have anomalously high methane concentrations, probably as a result of biological methanogenesis in subsurface organic-rich peat layers. Most of the regions sampled showed median values of the C1/(C2 + C3) ratio of < 20. The generally low C1 concentrations probably resulted from the selective loss of C1 by biologic oxidation or ebullition from the surface sediments. No major C2 to C4 hydrocarbon anomalies were discovered; however, at some stations in Kachemak Bay, Kodiak shelf, and Norton Sound, anomalously high C3/C3:1 ratios indicated the poss ble presence of thermogenic gases at depth.

Intertidal Variation in Foraminiferal Species Diversity: Mississippi-Louisiana Salt Marshes: ABSTRACT

Salt marshes are tide-stressed environments where ecologic variables exert strong selective control upon the distribution, type, and abundance of organisms. Ecologic conditions range from marine to terrestrial; hence gradational and/or abrupt environmental changes across marshes produce similar gradients in communities of organisms and their biotopes. Salt marshes are one of the present-day sites of peat accumulation. They represent a potential milieu for lignite and coal formation. Recognition of microenvironments within such marshes will provide coal explorationists and paleontologists with another tool for predicting the location of subsurface peats, lignites, and coals. Twenty-eight modern bottom samples were collected for analysis for foraminiferal populations (total = live + dead) in the Hancock County, Mississippi, and Pearl River, Louisiana, marshes during May and June 1981. Fourteen stations of the 28 were sampled twice--once at peak high tide and once at peak low tide. Three microbiotopes occur among the 14 stations: (1) beach (B)--3 localities, (2) lacustrine (L)--3 localities, and (3) bayou-fluvial (BF)--8 stations. Average salinities (parts/mil) at these biotopes were 10.4 (B), 2.3 (L), and 7.7 (BF). Ranges were 0.2 to 13.5. Average dissolved oxygen (ppm) values were 10.4 (B), 7.9 (L), and 5.4 (BF). Ranges were 2.6 to 12. Temperatures (°C) averaged 29.4 (B), 30.4 (L), and 29.3 (BF). Ranges were 20.9 to 32.7. We are currently studyin interbiotope and intrabiotope variability. After extracting a minimum of 300 specimens/sample, foraminiferal species diversity patterns among the 14 doubly sampled stations were studied. We used S (number of species), H(S) (Shannon-Wiener information function), and E (species equitability). The following ranges and average (x) exist at high tide: S--2 to 13, x = 7.4; H(S)--0.311 to 2.046, x = 1.25; E--0.306 to 0.720, x = 0.522. Low-tide samples have these ranges and averages: S--2 to 12, x = 7.0; H(S)--1.721 to 3.750, x = 1.08; E--0.326 to 0.727, x = 0.488. High-tide samples have much higher species diversity, slightly lower dominance, and are more equable. End_of_Article - Last_Page 499------------

A C-14 Date of a Subsurface Peat Layer in the Lower Reach of the Abukuma Valley, Northeast Japan

By the C-14 method, a peat layer in the column of Loc. 2 is dated 15, 800±350 yrs. B. P. (GaK-3374). This is the first valid date about the Quaternary geology of Sendai Lowland and its vicinity.This report is written to publish the date and to discuss on some relating informations. The subsurface geology and geomorphology of the area will be discussed in detail by Mr. Hiroaki Hase.

PEAT AND COMMERCIAL FERTILIZERS AS AMENDMENTS FOR GRAY WOODED SOILS

The nitrates in pot cultures of gray wooded soil were generally affected by the various amendments as follows: increased by applications of neutral or acid subsurface peat and not depressed by neutral or acid surface peat; increased by ammonium phosphate alone and in combination with the surface and subsurface peats, and by ammonium sulphate in combination with the subsurface peats, but slightly depressed by triple superphosphate in combination with the subsurface peats.The wheat crop yields in pot cultures of gray wooded soil were generally affected by the various amendments as follows: increased somewhat by peat alone, and especially by subsurface peat; increased substantially by ammonium phosphate alone, but increased to a greater extent in all three series by a combination of ammonium phosphate and subsurface peat; increased substantially by ammonium sulphate and subsurface peat, but not by triple superphosphate and peat.The plate counts of bacteria in treated cultures of gray wooded soil increased for two to four months, and then decreased. The ammonium phosphate plus subsurface peat treatment gave the highest counts, the ammonium phosphate plus surface peat the second highest, and the ammonium sulphate plus subsurface peat the third highest. The differences between the effects of triple superphosphate plus subsurface peat, ammonium phosphate, surface peat, and subsurface peat, were small. The control gave only a small increase during the course of the experiment.The ratio method showed that there are very large numbers of bacteria in gray wooded soil. Instead of ranging from about 500,000 to about 8,000,000 per gm. of soil as with the plate count method, the numbers varied from about 200,000,000 to 2,000,000,000. The numbers reached a maximum after three months' incubation. The ammonium phosphate plus subsurface peat treatment again gave the highest average number, and the succeeding order was also about the same as in the case of the plate counts.When mixed with gray wooded soil, surface peat, though highly carbonaceous, did not cause any significant decrease in nitrate at first, and produced some increase later. Straw caused some decrease at first, but the later recovery counterbalanced this loss. Cotton caused a decrease to practically none for about three months, and even when combined with ammonium phosphate caused some decrease. Ammonium phosphate alone and in combination with straw and surface peat produced large increases in nitrate. In a duplicate experiment with black soil the trends were similar, but the nitrate was not reduced to the same extent by straw and cotton, and when ammonium phosphate was added with the organic matter, nitrate was not reduced by peat, straw, or cotton.