Chlorophyll production,in response to nutrient additions,by the algae in Lake Rotorua water

Batch cultures of water and algae from Lake Rotorua were subjected to nitrogen, phosphorus, and trace element additions, singly and in combination, at monthly intervals between June 1975 and May 1976. The algal responses to the additions were assayed after 5 d incubation, by extracting the chlorophyll from the algae and estimating the concentration by fluorescence. The chlorophyll production consistently responded positively to the addition of nitrogen, while responses to the addition of phosphorus and trace elements were minor by comparison. Although the chlorophyll responses to nitrogen may not have been paralleled by actual growth, the consistent pattern of behaviour by algae in the batch cultures was interpreted as evidence of persistent shortage of nitrogen in the Lake Rotorua environment.     

Comparison of Monsoonal change of water quality parameters between 1983 and 2008 in a tropical estuary in Northeastern India: role of phytoplankton and community metabolism

Ongoing climate change and anthropogenic activities are introducing stressors that affect the structure and function of coastal ecosystems. This paper focuses on the fluvial fluxes and estuarine transport of nutrients from a tropical river (Mahanadi River) in Northeastern India and compares select nutrient and water quality parameters between 1983 and 2008. This estuary acts as a perennial source of CO₂ with a net annual flux to the atmosphere of about 135 tons. The non‐conservative fluxes showed a net annual removal of 650 and 140 tons of phosphorus and nitrogen from the water column, respectively. Negative biogeochemical feedbacks that decreased the availability of N and P in 2008 relative to 1983 levels indicate major changes in biogeochemical responses towards fluvial fluxes of nutrient.     

Seasonal distribution of cadmium among components of sewage treatment ponds: an eco-tech for heavy metal remediation

The study was designed to quantify cadmium accumulation in different components of sewage treatment ponds during different seasons and to assess risk for human consumption perspective. The study estimated cadmium concentration in water, sludge, Eichhornia, plankton and tilapia fish from anaerobic, facultative, maturation-1 and -4 ponds during pre-monsoon, monsoon and post-monsoon periods. It resulted that cadmium accumulated among different components of anaerobic, facultative, maturation-1 and -4 ponds ranging 0–18, 0–10, 0–7 and 0–15.4 ppb, respectively. During monsoon, highest accumulation was observed in tilapia in both facultative and maturation ponds, but during post-monsoon, plankton community showed highest value in all. The highest bio-magnification of cadmium was recorded during monsoon with varying degrees (facultative pond: 4.39, maturation pond-1: 3.03 and maturation pond-4: 7.08). Cadmium concentration in tilapia lied within WHO’s safe level and may be recommended for human consumption. The concentration of cadmium was estimated by Flame Atomic Absorption Spectrophotometer. The above findings occurred due to chelation, adsorption and sedimentation, absorption and bio-accumulation, ionization, leaching through sediment and rainfall. Water pH (6.7–8.8), dissolved oxygen (0–17 mg L^?1), total solids (251–650 mg L^?1), iron (Fe²⁺) concentration (0.61–4.87 mg L^?1) and sedimentation rate (278.9–2,409.6 g day^?1 m^?3) were conducive for the distribution of cadmium into different ecosystem components of treatment ponds. These ponds reclaimed 28.57–61.11 % of sewage-cadmium and may be promoted as a low-cost eco-tech for sewage treatment.     

Adsorption kinetic control of As(III &; V) mobilization and sequestration by Mangrove sediment

Elevated concentrations of arsenic in the sediment and pore water in the Sundarban wetlands pose an environmental risk. Adsorption and desorption are hypothesized to be the major processes controlling arsenic retention in surface sediment under oxic/suboxic condition. This study aims to investigate sorption kinetics of As(III & V) and its feedback to arsenic mobilization in the mangrove sediment. It ranges from sand to silty clay loam and shows the adsorption of As(III & V) following the Langmuir relation. Estimates of the maximum adsorption capacity are 59.11 ± 13.26 μg g⁻¹ for As(III) and 58.45 ± 8.75 μg g⁻¹ at 30°C for As(V) in the pH range 4 to 8 and salinity 15–30 psu. Extent of adsorption decreases with increasing pH from 4 to 8 and desorption is the rate-limiting step in the reaction of arsenic with sediment. Arsenic in the sediment could be from a Himalayan supply and co-deposited organic matter drives its release from the sediment. Arsenic concentration in the sediment is well below its maximum absorption capacity, suggesting the release of sorbed arsenic in pore water by the microbial oxidation of organic matter in the sediment with less feedback of adsorption.     

Zircon provenance of Quaternary cover beds using U–Pb dating: Regional differences in the Southwestern USA

U–Pb dating of detrital zircons (DZ) in Quaternary slope deposits (cover beds) and examination of the surface structure of single zircon grains may enable reconstruction of the provenance of their aeolian components and help to reconstruct sedimentary palaeo-transportation cascades. We distinguish several layers of slope deposits (cover beds) using a palaeosol-supported sequence-stratigraphic approach. In a pilot study, we demonstrate the usability of using end-member-modelled analyses of grain sizes to identify the aeolian matter, multi-dimensional scaling and density functions (probability density functions (PDF) and Kernel density estimations (KDE)) of the U–Pb data, and the grain morphology of DZ, and show that the age and appearance variation of DZ in the Great Basin differ remarkably from those of the Colorado Plateau. All samples contain aeolian matter. Density functions of the DZ ages show similarities within each of the two regions. The Great Basin samples are dominated by late Cretaceous and Paleogene zircons, which are assumed to derive from volcanism. In contrast, the Colorado Plateau samples are almost free of these contributions. Presumably, the difference is due to palaeolakes, which were frequent in the Great Basin only, whose sediments contain a similar spectrum of DZ ages. Zircon morphology indicates that most grains have a history of aeolian transportation, whereas the grains assumed to be of volcanic origin often do not show similar transportation marks; this indicates that their transportation was dominated by the eruptive process but fewer steps of a transportation cascade. Multidimensional scaling of age data defines clusters of samples with similar DZ ages and – compared with published ages from possible sources – allows first interpretations of provenance. Quaternary aeolian sediments have not been studied in, and the applied mix of methods has not been applied to, the southwestern USA before. We demonstrate their feasibility for this study area.     

The geometry of the Burmese-Andaman subducting lithosphere

The gross seismotectonic features for the Burmese-Andaman arc system which defines the northeast margin of the Indian plate are rather well known but variations in the subduction zone geometry along and across the arc and fault pattern within the subducting Indian plate have not been studied. Present workaims to study these by using seismicity data whose results are presented in the form of: (a) Lithospheric across-the-arc sections at about every 100–120 km (approximately one degree latitude apart) covering the 3500 km longBurmese-Andaman arc system, (b) a structure contour map showing the depth tothe top surface of the seismically active lithosphere and (c) interpretationof focal mechanism solutions for 148 Benioff zone earthquakes. Both penetrationdepth and the dip of the Benioff zone vary considerably along the arc in correspondence to the curvature of the fold-thrust belt which varies from concave to convex in different sectors of the arc. Several extensive `Hinge faults' that abut at high angles to the arc orientation, are inferred from aninterpretation of the structure contour map. Active nature of the hinge faultsis established in several areas by their association with earthquakes andcorroborated through fault plane solutions. At shallow level of the Benioffzone along these faults, focal mechanism solutions display left lateral strikeslip movement while at deeper levels reverse fault solutions are common.     

Electromagnetic measurements in the vicinity of the KTB drill site. Part II. Magnetotelluric results

Summary In addition to the magnetovariational measurements across an array in Western Bohemia, close to the KTB ultradeep borehole (Germany), discussed in part I of this paper [1], magnetotelluric results from pivot sounding point Ostrvek within the array are presented here. Good quality of long-period magnetotelluric data (period range from 30 s to about 1 hour) allowed structural dimensionality of the medium to be analysed in detail. The geoelectrical structure was identified as a slightly distorted two-dimensional regional substratum, with dominating E - W strike, overlaid by a heterogeneous subsurface layer with extremely strong and anisotropic galvanic distortion effect on the magnetotelluric data. Estimating the total static shift distortion tensor by fitting the local magnetotelluric curve to the curve of the global magnetovariational soundings (for the European continent), the static distortions were identified as of generally multidirectional origin. The resulting telluric ellipse is, however, strongly anisotropic, indicating an approximately SW - NE apparent local strike, which is in the approximate agreement with remote reference magnetovariational results. Finally, the magnetotelluric results from the station Ostrvek are compared with long-period data from the immediate neighbourhood of the KTB borehole on the German territory.     

Deep electrical structure under central Europe

Summary The model of the electrical conductivity distribution within the Bohemian Massif to mid-upper mantle depths was derived from magnetotelluric and magnetic continuum long-period data of the Budkov Observatory (Geophysical Institute, Acad. Sci. Czech Republic., Prague) and from the ISL (Induction Scale Lengths) data of the Prhonice Observatory. The ranges of apparent resistivities in the Bohemian Massif (BM) are compared with those obtained at relevant central European observatories. The conductivity profile is estimated from the resistivity/depth graph corresponding to substitute perfect conductor inversion.Dedicated to the Memory of Professor Karel P     

The spray volume shed by an uncambered planing hull in steady planing

Earlier papers (Payne, 1981 a,b,c) have developed what might be called a virtual mass theory which in principle permits the forces on any planing hull form to be calculated. In the present paper, this methodology is extended to calculate the thickness and momentum of the jet or spray sheet thrown off by the planing surface. For a two-dimensional flat planing plate—the only case where comparison is possible—the theory gives essentially the same result as that of Pierson and Leshnover (1948). For a three-dimensional flat plate and prismatic hulls, the results seem physically reasonable.For the small trim angles associated with efficient planing, on a weightless inviscid fluid the total pressure drag of any hull can be reduced to close to zero by deflecting the jet rearwards and parallel to the undisturbed surface, the residual resistance being due to the cross-flow force which varies as (trim angle)².