Miracle-dz/UniFAR-FTUs huggingface dataset:
Microbial methane production rates in gas hydrate-bearing sediments from the eastern Nankai Trough, off central Japan

Gas hydrates and associated high methane concentrations are widely distributed along the boundary of the Nankai Trough off Japan. Radiotracer activity measurements were conducted to estimate current methane production rates in sediment cores at two sites in the eastern Nankai Trough off Tokai containing gas hydrates. Low rates of methanogenesis from CO2 reduction and acetate fermentation were detected within the gas hydrate-stability zone and below the Bottom Simulating Reflector (BSR), but not in sediments from shallow depths (<100 mbsf). The detected production rates of methane from acetate were much higher than those from carbon dioxide and hydrogen. Methanol or potentially some other methyl compounds could also be used for microbial methane production. Deep methane production rates from acetate in the gas hydrate-bearing sediments were higher than in pre-accretionary, hydrate-free sediments at sites 1173, 1174 and 1177 of ODP Leg 190 from the floor of the western Nankai Trough off Shikoku Island. As previously suggested this might be due to upward fluid flow stimulating bacterial activities around and below the base of the gas hydrate zone. In contrast, methanogenesis from carbon dioxide and hydrogen was the main pathway for microbial methane production in the hydrate-free sediments at the ODP Nankai Trough sites.
On the structure of mare basalt lava flows from textural analysis of the LaPaz Icefield and Northwest Africa 032 lunar meteorites

Abstract— Quantitative textural data for Northwest Africa (NWA) 032 and the LaPaz (LAP) mare basalt meteorites (LAP 02205, LAP 02224, LAP 02226, and LAP 02436) prvide constraints on their crystallization and mineral growth histories. In conjunction with whole‐rock and mineral chemistry, textural analysis provides powerful evidence for meteorite pairing. Petrographic observations and crystal size distribution (CSD) measurements of NWA 032 indicate a mixed population of slowly cooled phenocrysts and faster cooled matrix. LaPaz basalt crystal populations are consistent with a single phase of nucleation and growth. Spatial distribution patterns (SDP) of minerals in the meteorites highlight the importance of clumping and formation of clustered crystal frameworks in their melts, succeeded by continued nucleation and growth of crystals. This process resulted in increasingly poor sorting, during competition for growth, as the melt crystallized. Based on CSD and SDP data, we suggest a potential lava flow geometry model to explain the different crystal populations for NWA 032 and the LaPaz basalts. This model involves crystallization of early formed phenocrysts at hypabyssal depths in the lunar crust, followed by eruption and flow differentiation on the lunar surface. Lava flow differentiation would allow for formation of a cumulate base and facilitate variable cooling within the stratigraphy, explaining the varied textures and modal mineralogies of mare basalt meteorites. The model may also provide insight into the relative relationships of some Apollo mare basalt suites, shallow‐level crystal fractionation processes, and the nature of mare basalt volcanism over lunar history.
Stratigraphic filtering, Part I, Derivation of the O'Doherty-Anstey formula

We present a new and more detailed derivation of the formula due to O’Doherty and Anstey (1971) for filtering a transmitted wavelet by short‐period multiples. We use a continuous rather than discrete formulation and regard the impedance as a random variable. The mean pressure represents the downgoing wavelet as progressively modified by short‐period multiples, while the deviations from the mean field are essentially the upcoming reflections. Standard procedures and approximations lead to the dispersion relation of the mean pressure field. To describe the stratigraphic filtering, we introduce a dimensionless complex quantity F such that a wavelet which has traveled a time ΔT is modified by the filter A(ω)=expiω(FΔT). From the Kramers‐Kronig relation appropriate for a causal earth, F has real and imaginary parts F1=12Q=R(ω)ω=12ωMˆ(ω), and FR=σtΔT=1π∫-∞+∞dyF1(y)y-ω, Where Q and δt define the apparent attenuation and time delay, both of which may depend upon frequency, R is the spectrum of reflection coeffici.
Vertical and lateral flux on the continental slope off Pakistan: correlation of sediment core and trap results

Due to the lack of bioturbation, the varve-laminated muds from the oxygen minimum zone (OMZ) off Pakistan provide a unique opportunity to precisely determine the vertical and lateral sediment fluxes in the nearshore part of the northeastern Arabian Sea. West of Karachi (Hab area), the results of two sediment trap stations (EPT and WPT) were correlated with 16 short sediment cores on a depth transect crossing the OMZ. The top of a distinct, either reddish- or light-gray silt layer, 210 Pb-dated as AD 1905 ± 10, was used as an isochronous stratigraphic marker bed to calculate sediment accumulation rates. In one core, the red and gray layer were separated by a few (5–10) thin laminae. According to our varve model, this contributes −2 d −1 . Based on core results, the flux at the seafloor amounts to 4000 mg m −2 d −1 and agrees remarkably well with the bulk winter flux of material, as well as with the flux of the individual bulk components of organic carbon, calcium carbonate and opal. However, due to the extreme mass of remobilized matter, the high winter flux events exceeded the capacity of the shallow traps. Based on our comparisons, we argue that high-flux events must occur regularly during winter within the upper OMZ off Pakistan to explain the high accumulations rates. These show distribution patterns that are a negative function of water depth and distance from the shelf. Some of the sediment fractions show marked shifts in accumulation rates near the lower boundary of the OMZ. For instance, the flux of benthic foraminifera is lowered but stable below ~1200–1300 m. However, flux and sedimentation in the upper eastern Makran area are dominated by the large amount of laterally advected fine-grained material and by the pulsed nature of the resuspension events at the upper margin during winter.
Evaluating multiple colour-producing agents in Case II waters from Lake Erie

Lake Erie is part of the Great Lakes systems in North America, which represent the largest continental lake systems in the world. Anthropogenic eutrophication in the Western Basin of Lake Erie, a Case II environment, has an adverse impact on the surrounding ecosystems and the regional economy. The optical complexity found in Lake Erie is a feature of many aquatic environments making it a challenging setting for remote-sensing applications. To assess the controls on these optical properties, we sampled 20 locations, encompassing a variety of optical environments in the Western Basin and Sandusky Bay during four research cruises. Strong correlations between light extinction and phycocyanin (correlation coefficient, r ≥ 0.95), suspended sediment (r = 0.90), and chlorophyll-a (r ≥ 0.86) indicate that surface conditions are representative down to at least the first optical depth. Application of varimax-rotated principal component analysis to lab-based, hyperspectral reflectance data identified three components related to a diatom/green algae community, and two blue-green algae communities, one of which was associated with suspended sediment. Phycocyanin and chlorophyll-a content inferred using a semi-analytic red/near-infrared algorithm correlated well with concentrations measured in situ using a multiparameter sonde. Chlorophyll-a retrievals from a regional, blue : green algorithm developed for the Western Basin of Lake Erie compared well with retrievals from the semi-analytic algorithm for all samples from the Western Basin and 25% of samples from Sandusky Bay. Chlorophyll-a retrieval errors using the blue : green algorithm occurred when high ratios of suspended sediment to phycocyanin biased samples from the extremely turbid waters of Sandusky Bay. The bias likely resulted when suspended sediment altered the blue : green ratio or when phycocyanin interfered with the chlorophyll-a absorption peaks. This approach can be applied to other Case II environments to provide insights during the design of experimental field studies and for spectral band selection with the next generation of visible near-infrared remote-sensing instruments.
Iberian autumnal precipitation characterization through observed, simulated and reanalysed data

Abstract. A 44-year (1958–2001) homogeneous Mediterranean high-resolution atmospheric database was generated through dynamical downscaling within the HIPOCAS Project framework. The present work attempts to provide a validation of the monthly 41-autumnal (1961–2001) HIPOCAS precipitation over the Iberian Peninsula, being also provided an evaluation of its improvement versus current global reanalysis data sets. A statistical comparative analysis between observed, HIPOCAS and global reanalyses precipitation data sets was carried out, highlighting the noticeable agreement existing between the observed and the HIPOCAS precipitation data sets in terms of not only time and spatial distribution, but also in terms of total amount of precipitation. A principal component analysis is carried out showing that the patterns derived from the HIPOCAS data largely capture the main characteristics of the studied field. Moreover, it is worth to note that the HIPOCAS patterns reproduce accurately the observed regional characteristics linked to the main orographic features of the study domain.
Modelling residence‐time response to freshwater input in Apalachicola Bay, Florida, USA

Residence time of an estuary can be used to estimate the rate of removal of freshwater and pollutants from river inflow. In this study, a calibrated three‐dimensional hydrodynamic model was used to determine residence time in response to the change of freshwater input in Apalachicola Bay. The bay is about 40 km long and 7 km wide, with an average 3 m water depth. Through hydrodynamic model simulations, the spatial and temporal salinity and the total freshwater volume in the bay were calculated. Then the freshwater fraction method was used to estimate the residence time. Results indicate that the residence time in Apalachicola Bay typically ranges between 3 and 10 days for the daily freshwater input ranging from 177 m3/s to 4561 m3/s. Regression analysis of model results shows that an exponential regression equation can be used to correlate the estuarine residence time to changes of freshwater input. Copyright © 2002 John Wiley & Sons, Ltd.
Fluvial response to horizontal shortening and glaciations : A study in the Southern Alps of New Zealand

[1] It has been postulated that a steady state between erosional and tectonic processes may develop in continental collision. However, it is not clear whether steady state conditions can be reached for all components of the landscape. Here we show, using landscape evolution models and field evidence, that a true geomorphic steady state may never be reached in the Southern Alps of New Zealand. The strong asymmetries in tectonic uplift and tectonic advection and the onset of glaciations constantly interact to prevent the landscape from reaching a topographic steady state. Evidence suggests that the first-order geomorphology on the western side of the Southern Alps is controlled by orographic precipitation combined with extreme rates of tectonic uplift, whereas the development of deep glacial valleys on the eastern side is initiated by differential uplift along large faults. We also develop a first-order equation, governing the dynamics of the Main Divide, to show that both tectonic advection and fluvial erosion efficiency control the position and the height of the main drainage divide. Using a two-dimensional landscape evolution model, we demonstrate that the transition from glacial to fluvial conditions at the end of the last glaciation led to substantial modifications of the landscape: While the main trunk channels get slowly uplifted, ridges are leveled down, causing the relief to decrease. Hillslopes appear to be affected by fluvial processes which seem to be driven by incision of river tributaries. This reduction of relief will probably never reach a steady state since warmer interglacial periods are substantially shorter than glacial periods.
The role of atomic chlorine in glacial‐interglacial changes in the carbon‐13 content of atmospheric methane

The ice‐core record of the carbon‐13 content of atmospheric methane (δ13CH4) has largely been used to constrain past changes in methane sources. The aim of this paper is to explore, for the first time, the contribution that changes in the strength of a minor methane sink―oxidation by atomic chlorine in the marine boundary layer (ClMBL)―could make to changes in δ13CH4 on glacial‐interglacial timescales. Combining wind and temperature data from a variety of general circulation models with a simple formulation for the concentration of ClMBL, we find that changes in the strength of this sink, driven solely by changes in the atmospheric circulation, could have been responsible for changes in δ13CH4 of the order of 10% of the glacial‐interglacial difference observed. We thus highlight the need to quantify past changes in the strength of this sink, including those relating to changes in the sea‐ice source of sea salt aerosol.
Sponge borehole size as a relative measure of bioerosion and paleoproductivity

Bioerosion intensity has been proposed as a measure of paleoproductivity in fossil reefs, but it is difficult to measure directly because fossil corals are often incomplete and because it is difticult to infer the length of time a given coral was exposed to bioeroding organisms. Both nutrient availability and taphonomic factors can affect bioerosion intensity as measured in dead corals. Here, we examine these two effects separately using data from previous studies on bioerosion in modern and fossil corals. Size of individual sponge borings accurately reflects total bioerosion in modern massive and branching corals on the Great Barrier Reef. Total bioerosion in both massive and branching corals decreases outward across the continental shelf, paralleling trends in nutrient availability. Size of individual Cliothosa hancocki borings decreases across the shelf in branching Acropora but not in massive Porites. Fossil sponge borings Entobia convoluta and Uniglobites glomerata in massive corals from Oligocene and Miocene reefs in Puerto Rico are smallest in Oligocene shelf-edge reefs, intermediate in Oligocene patch reefs, and largest in Miocene patch reefs. Both facies-related influence, represented by Oligocene shelf-edge reefs vs. Oligocene patch reefs, and nutrient-related influence, represented by Oligocene vs. Miocene patch reefs, were reflected in the size of sponge boreholes. Size of sponge borings also varies among species of host corals, apparently in relation to skeletal architecture. Borehole size is inversely correlated with skeletal density as measured by the relative proportion of skeleton and pore space in transverse thin section. There is a weak positive correlation between borehole size and corallite diameter. These findings contradict reported positive correlations between total bioerosion and bulk density in modern corals. Borehole size appears accurately to reflect intensity of total internal bioerosion in fossil corals. Facies-controlled taphonomic overprints and influence of skeletal differences between coral species limit the use of sponge borehole size to a rough indicator of paleoproductivity in fossil coral reef environments.
Hydraulic conductivity of homogenized tailings from hard rock mines

Tailings produced by milling for one extraction from hard rock mines, which range in size from clay to fine sand, have relatively low hydraulic conductivity, k. The value of k must be known with a certain degree of certainty to analyze consolidation and seepage conditions in and around tailings ponds. In this paper, the authors present the results of a laboratory investigation on hydraulic conductivity of homogenized tailings from hard rock mines. After describing some of the basic properties of four different materials, including mineralogy, grain size, Atterberg limits, compaction characteristics, and consolidation curves, permeability test results are given. The hydraulic conductivity value usually varies between 104 and 105 cm/s. The effect of various factors on this value, including void ratio and grain size, is then discussed in relation to predictive models. It is shown that a modified version of the Kozeny-Carman equation, in which a tortuosity factor and a grain-size distribution function are i.
Heat source for Tongonan Geothermal Field

Abstract The primary mineral and whole‐rock chemistry of 46 core samples from the host rocks of the Tongonan Geothermal Field (the Philippines) have been used to infer the likely composition of the heat source for the system. The host rocks consist of andesite lavas (with intercalated fossiliferous early to mid–Miocene shales and limestone), and a plutonic rock basement ranging in composition from gabbro to granite. The whole rock TiO2, Fe2O3 (total iron), MgO, P2O5 and V data for volcanic and plutonic rocks are colinear on conventional Harker diagrams. This, along with similar hornblende chemistry, age and close spatial relationship suggests that the basement and cover rocks are cogenetic and evolved by low‐pressure crystal fractionation. Crystal fractionation models indicate that separation of 60% plagioclase and 30% hornblende from original magma controlled the chemistry of the host rocks. The original Miocene magma chambers beneath the Tongonan field crystallized inwards from the walls at approximately 750°C and 1 kb pressure (3–4 km depth) thus forming a series of plutons or a batholith at drilled depths. A supercritical hydrothermal fluid trapped in the crystallizing, hornblende‐granite‐pegmatite core of a crystallized Miocene diorite batholith was gradually being released to shallower levels through antithetic cross fractures during creep and uplift along the main branches of the Philippine Fault from the Pliocene. This ascending fluid is now thought to be responsible for the present thermal activity of the field.
ASSESSMENT OF THE EFFICIENCY OF DIFFERENT MIXES OF MACROPHYTES IN REMOVING HEAVY METALS FROM WASTEWATER USING CONSTRUCTED WETLAND

Industrial wastewater has high quantities of heavy metals emanating from industrial processes. Theseheavy metals need to be removed before the wastewater is released to the environment. Constructedwetlands are inexpensive and highly effective in removal of heavy metals from wastewater. This study assessed the efficiency of different mixes of macrophytes Polygonum spp, Typha latifolia and Papyruscyperus (X,Y,Z) to remove zinc, lead and cadmium from municipal wastewater using constructed wetlands. The model wetlands were wash basins with an outlet at the bottom. A total of 16 basins were used, 12 of which were planted and 4 unplanted to act as control (4 treatments with 3 replicates). Quarry dust (¼”) was used as the substrate in each basin. 12 plants (X,Y,Z) were planted in mixes of 1:1:1, 2:1:1, 1:2:1 and 1:1:2 respectively. Wastewater was collected from Thika municipal treatment works and analyzed for Zinc, Lead and Cadmium using Atomic Absorption Spectrophotometer before being introduced into the wetlands. Samples from the wetlands were collected after 4, 6 and 8 days for analysis for several runs. Plant samples were harvested and concentration of heavy metals determined.The results showed that treatment with more of Polygonum spp achieved highest removal for Zinc (80.5%), treatment with more of papyrus achieved the highest removal for Lead (89.8%) while maximum removal for Cadmium was achieved when the macrophytes were in equal ratios. The treatment with 6 Polygonm spp, 3 Typha spp and 3 Papyrus spp recorded relative high removal rates for all metals and was recommended as the best mix. The analysis of the metals in the macrophytes indicated increasing absorbance; Papyrus spp >Typha spp >Polygonum spp. The concentrations of the Zinc and Cadmium in the effluent sewage were below the maximum allowable concentrations for discharge into the environment. The constructed wetlands were therefore effective in reducing the heavy metals concentrations from the raw sewage to tolerable levels.
An evaluation of multi-date SPOT data for agriculture and land use mapping in the United Kingdom

Abstract Four SPOT HRV images of the same area of East Anglia, acquired between February and September 1986, have been evaluated at the National Remote Sensing Centre for their potential use in agricultural land cover mapping. Spectral coincidence plots were used in feature selection. Information from single images contained a high level of spectral confusion between cover types. Vegetation index images and original data were used in supervised maximum likelihood classification. Higher classification accuracies were achieved using the original data than the vegetation indices. An overall classification accuracy of 71 per cent for 10 land cover types was improved to 88 per cent by reducing the number of classes. Although the imagery acquired for the study did not correspond well to key dates in the crop calendar, the broad land cover categories, cereal crops, field crops (sugar beet and vegetables), grass land and broadleaved woodlands could be mapped from SPOT. Using vegetation indices from the whole scen.
A numerical study of the relationship between NMR relaxation and permeability in sands and gravels

The accuracy of NMR-derived permeability estimates in sands and gravels are examined through simulations on numerical grain packs composed of uniform spherical grains. The packs consisted of randomly packed grains, with grain sizes set to represent a range corresponding to sands and gravels. The material properties for each pack were quantified through numerical analysis and the NMR response was simulated for a range of surface relaxivity values. The agreement between the numerically-derived permeability estimates and the permeability estimates derived using the Schlumberger-Doll Research (SDR) and Seevers equations was evaluated. Use of the SDR equation assumes that the relaxation of the bulk pore fluid can be neglected. The NMR-derived permeability estimates were calculated using each equation for the cases where relaxation was assumed to occur in one of the two major diffusion regimes. We found that permeability is most accurately estimated in all packs through use of the Seevers equation with the empirical constant n set equal to 1. We showed that the contribution of bulk fluid relaxation should be accounted for in materials with grain radii greater than 1.2e-4m (fine sand) and surface relaxivity values less than 1.0e-3 m s-1. In practice, this range of surface relaxivity values and grain sizes corresponds to situations where the measured relaxation time T2 is greater than approximately one-third the value of the bulk fluid relaxation time T2B.
Climatic Feedbacks during the 2003 European Heat Wave

AbstractDuring the summer of 2003, a record heat wave over Europe occurred, to which the deaths of over 20 000 people in 18 countries were attributed, 10 000 of those in France alone. Temperatures across Europe were above normal for most of the summer, but reached their peak during the first two weeks of August, when most of the deaths occurred.Ensemble simulations done with a recent version of the Center for Ocean–Land–Atmosphere Studies (COLA) atmospheric general circulation model (AGCM) have been analyzed over the European region. The simulations were forced by weekly mean observed sea surface temperature (SST). Relative to the 1982–2001 period, the COLA AGCM simulated anomalous warmth over the European region during June–August 2003, in response to the observed SST; however, the simulated magnitude was smaller than that observed. A series of simulations in which the observed SST was used only south of 25°N or only north of 25°N suggest that it was the influence of the local SST rather than remote SST .