Transformation of Lambert Conic Conformal Coordinates from a Global Datum to a Local Datum

This paper treats the problem of how to transform from global datum, for example, from the International Terrestrial Reference System (ITRS), to a local datum, for example, regional or national, for the practical case of the Lambert projection of the sphere or the ellipsoid-of-revolution to the cone. We design the two projection constants n(ϕ₁, ϕ₂) and m(ϕ₁) for the Universal Lambert Conic projection of the ellipsoid-of-revolution. The task to transform from a global datum with respect to the ellipsoid-of-revolution E_A,B² to local datum with respect to the alternative ellipsoid-of-revolution E_a,b², without local ellipsoidal height, is solved by an extended numerical example. Ideas in this paper could be of interest to those working with maps and coordinates transformation from global geodetic datum to local geodetic datum and vice versa, under the Universal Lambert Conic projection, and applicable to precise positioning and navigation, boundary demarcation and determination in the marine environment.     

Comparisons between the influences of habitat, body size and season on the dietary composition of the sparid Acanthopagrus latus in a large marine embayment

Seasonal samples from Shark Bay on the west coast of Australia were used to determine (1) the habitats occupied by the juveniles and adults of Acanthopagrus latus in this large subtropical marine embayment and (2) the extent to which the dietary composition of this sparid is influenced by habitat type, body length and season. Sampling was undertaken in two habitat types in which A. latus was known to be abundant, namely mangrove (Avicennia marina) creeks and nearby rocky areas, the latter comprising sandstone boulders and/or limestone reefs. The mean total length ±95% CLs of A. latus was far lower in mangrove creeks, 126 ± 6.1 mm, than in rocky areas, 313 ± 4.7 mm. As A. latus attains maturity at ca. 245 mm, the juveniles of this species typically occupy mangrove areas and then, with increasing body size, move to nearshore rocky areas, where they become adults. The species composition of the food ingested by juvenile A. latus in mangrove creeks differed markedly from that of large juveniles and adults in rocky areas. Based on analyses of data for both habitat types combined, this difference was far greater than that between size classes and season, which was negligible. There were indications, however, that, overall within each habitat, the dietary composition did change seasonally, although not with body size. Acanthopagrus latus fed predominantly on mangrove material, sesarmid crabs and small gastropods in mangrove habitats, and mainly on Brachidontes ustulatus in rocky areas, where this mytilid bivalve is very abundant. The mangrove material, which contributed nearly 40% of its overall dietary volume in mangrove creeks, consisted mainly of lateral root primordia. This apparently unique food source for a teleost is presumably ingested through subsurface nipping, which would be facilitated by the mouth and dentitional characteristics of sparids. The almost total lack of correspondence in the dietary compositions of fish in the length class that was well represented in both mangrove and rocky areas illustrates the extent to which this sparid is capable of opportunistic feeding behaviour.     

Atmospherically-promoted photosynthetic activity in a well-mixed ecosystem: Significance of wet deposition events of nitrogen compounds

Wet atmospheric deposition of dissolved N, P and Si species is studied in well-mixed coastal ecosystem to evaluate its potential to stimulate photosynthetic activities in nutrient-depleted conditions. Our results show that, during spring, seawater is greatly depleted in major nutrients: Dissolved Inorganic Nitrogen (DIN), Dissolved Inorganic Phosphorus (DIP) and Silicic acid (Si), in parallel with an increase of phytoplanktonic biomass. In spring (March–May) and summer (June–September), wet atmospheric deposition is the predominant source (>60%, relative to riverine contribution) for nitrates and ammonium inputs to this N-limited coastal ecosystem. During winter (October–February), riverine inputs of DIN predominate (>80%) and are annually the most important source of DIP (>90%). This situation allows us to calculate the possibility for a significant contribution to primary production in May 2003, from atmospheric deposition (total input for DIN ≈300 kg km⁻² month⁻¹). Based on usual Redfield ratios and assuming that all of the atmospheric-derived N (AD-N) in rainwater is bioavailable for phytoplankton growth, we can estimate new production due to AD-N of 950 mg C m⁻² month⁻¹, during this period of depletion in the water column. During the same episode (May 2003), photosynthetic activity rate, considered as gross primary production, was estimated to approximately 30 300 mg C m⁻² month⁻¹. Calculation indicates that new photosynthetic activity due to wet atmospheric inputs of nitrogen could be up to 3%.     

Estimation of Uplift Capacity of Rapidly Loaded Plate Anchors in Soft Clay

Plate anchors are extensively used in civil engineering constructions as they provide an economical alternative to gravity and other embedded anchors. The rate of loading is one of the important factors that affects the magnitude of soil resistance as well as soil suction force. This article outlines the effect of pullout rate on uplift behavior of plate anchors (70 mm diameter) buried in soft saturated clay by varying the pullout rate from 1.4 mm/min to 21.0 mm/min. The variation of breakout force and suction force with embedment depth and rate of pull are presented. A correlation between the rate of increase of undrained strength of clay and anchor capacity with rate of strain has been established. Finally an empirical equation has been proposed that includes the rate of pull in the estimation of breakout capacity of anchors.     

Geological structure of the Curonian Spit (of the Baltic Sea) and its evolution history (revised)

The origin and evolution history of the Curonian Spit in the Baltic Sea are discussed based on geological and geomorphologic data. Evidence of the correlation between the spit formation stages and the Holocene sea level oscillations is presented. The ledges of moraine basement and marine accumulative features formed a single barrier. Its subsequent transformation occurred under the influence of the wave-related lithodynamic and eolian processes.     

The Pechora Sea: Past,recent, and future

The main stages in the development of the Pechora Sea are discussed. It is established that, during the high sea level stand corresponding to the warmest epoch of the Mikulino Interglacial, the Pechora Sea represented a more spacious, as compared with its present-day size, basin owing to the flooded valleys of river lower reaches. No sea in its present-day configuration existed during the last (Valdai) glaciation. At that time, the sea could have occupied only a narrow area along the southern coast of Novaya Zemlya, where marine sedimentation was in progress during the Late Pleistocene and Holocene. During the glaciation and postglacial time, the dried bottom of the former Pechora Sea accumulated large volumes of sand that are now concentrated largely in the accretion structures along its southern coast. In the current century, changes will occur mainly in the coastal zone of the Russkii Zavorot Peninsula, Pesyakov Island, the Varandei Settlement area, and the Medynskii Zavorot Peninsula, where a shoreline retreat for a distance of 0.5 km is expected.     

A comparative mineralogical study of gas-related sediments of the Gulf of Cádiz

The Gulf of Cádiz area has been extensively surveyed in recent years and several gas-related fluid escape seafloor structures have been identified. In this study, gravity cores, collected during the ANASTASYA/00 and ANASTASYA/01 cruises, on mud volcanoes, hemipelagic sediments and dredged material from diapiric structures, have been studied. A comparative mineralogical analysis by XRD and SEM of samples from different areas has been performed in order to determine whether there is a characteristic mineralogy related to these fluid escape structures, and also to determine the origin of the mud matrix and constrain the depth of the parent units. The mineralogical analysis reflects the different origins of the different units described in the cores: hemipelagic material of the slope, clays that underlie the mud volcanoes and are discharged at the sea bottom surface, and authigenic and diagenetic minerals possibly involved in the anaerobic oxidation of methane in the mud volcano sediments.     

Response behaviour of triangular tension leg platforms under impact loading

Excellent station keeping characteristics and relative insensitivity with increasing water depth make triangular tension leg platforms (TLPs) a proven concept in deep water oil exploration. TLPs are often subjected to less probable forces which arise due to collision of ships, icebergs or any other huge sea creature. Dynamic analysis of two triangular TLP models at water depths 1200 and 527.8 m is performed under regular waves along with impulse load acting at an angle of 45 degrees at the TLP column. Hydrodynamic forces on these TLPs are evaluated using modified Morison equation, based on water particle kinematics arrived at using Stokes’ fifth order wave theory. Based on numerical studies conducted, it is seen that impulse loading acting on corner column of TLP significantly affect its response while that acting on pontoons dose not affect TLPs behaviour.     

Mixed layer variability in Northern Arabian Sea as detected by an Argo float

Seasonal evolution of surface mixed layer in the Northern Arabian Sea (NAS) between 17° N–20.5° N and 59° E-69° E was observed by using Argo float daily data for about 9 months, from April 2002 through December 2002. Results showed that during April - May mixed layer shoaled due to light winds, clear sky and intense solar insolation. Sea surface temperature (SST) rose by 2.3 °C and ocean gained an average of 99.8 Wm⁻². Mixed layer reached maximum depth of about 71 m during June - September owing to strong winds and cloudy skies. Ocean gained abnormally low ∼18 Wm⁻² and SST dropped by 3.4 °C. During the inter monsoon period, October, mixed layer shoaled and maintained a depth of 20 to 30 m. November - December was accompanied by moderate winds, dropping of SST by 1.5 °C and ocean lost an average of 52.5 Wm⁻². Mixed layer deepened gradually reaching a maximum of 62 m in December. Analysis of surface fluxes and winds suggested that winds and fluxes are the dominating factors causing deepening of mixed layer during summer and winter monsoon periods respectively. Relatively high correlation between MLD, net heat flux and wind speed revealed that short term variability of MLD coincided well with short term variability of surface forcing.     

Offshore marine conservation policies in the North East Atlantic: Emerging tensions and opportunities

An inherent tension exists between legal approaches to nature conservation and fisheries management in the European Union, as the former remains the remit of Member States while the latter is under the exclusive legislative jurisdiction of the European Community (EC). This tension is of particular importance when addressing the conservation of habitats or species that are under threat from fishing activities. This article examines recent developments in offshore marine conservation in the North-East Atlantic in light of the legislative developments and political frameworks that are currently evolving. By analysing the emergency closure of the Darwin Mounds area of cold-water corals and the UK pair-trawl ban, it becomes evident that the precautionary principle is a key factor in the tension between fisheries management and marine nature conservation, and is not always taken into account.