Reproductive biology of Mustelus lenticulatus from Kaikoura and Nelson

Mustelus lenticulatus is a non‐placental ovoviviparous shark with a gestation period of about 11 months. Young are born at a total length of 30–32 cm from September to December. Copulation, and ovulation of a further set of eggs, rapidly follows parturition. Fecundity increases with the length of the female; the most eggs found in one female was 24; the mean for all females was 10.73.

Males mature at about 85 cm total length and females at 95 cm at Kaikoura. Nelson males probably mature at a smaller size than do Kaikoura males. Nelson females mature at about 85 cm. Maximum observed lengths were 137 cm for females and 115 cm for males.     

Large-scale laboratory experiment on erosion of sand beds by moving circular vertical jets

This study investigates the topographic deformation due to the erosion of a sand bed impinged by a moving submerged turbulent round jet in a large-scale laboratory. The test conditions represent the case of discharges beneath a vessel while operating in water with a limited clearance such as a shallow navigation channel. The jet moves horizontally and discharges water vertically downward towards the bed. The distance between the jet nozzle and the bed equals six times the jet diameter so the jet flow is in the potential core region. The speed of the jet horizontal motion was varied to examine its effect on the scour profile. The characteristic lengths of the scour profile in the asymptotic state were determined by modifying the empirical formulas in Aderibigbe and Rajaratnam [1996. Erosion of loose beds by submerged circular impinging vertical turbulent jets. Journal of Hydraulic Research 34(1), 19–33]. The maximum scour depth, the scour hole radius, and the ridge height were found to be a function of the ratio of the jet exit to jet translation velocities and were modeled using a hyperbolic function. Empirical equations describing the scour profile were developed and the scour profile was found to be self-similar when normalized by appropriate length scales.     

Thermodynamic characterization of boltwoodite and uranophane: Enthalpy of formation and aqueous solubility

Boltwoodite and uranophane are uranyl silicates common in oxidized zones of uranium ore deposits. An understanding of processes that impact uranium transport in the environment, especially pertaining to the distribution of uranium between solid phases and aqueous solutions, ultimately requires determination of thermodynamic parameters for such crystalline materials. We measured formation enthalpies of synthetic boltwoodites, K(UO₂)(HSiO₄)·H₂O and Na(UO₂)(HSiO₄)·H₂O, and uranophane, Ca(UO₂)₂(HSiO₄)₂·5H₂O, by high temperature oxide melt solution calorimetry. We also studied the aqueous solubility of these phases from both saturated and undersaturated conditions at a variety of pH. The combined data permit the determination of standard enthalpies, entropies and Gibbs free energies of formation for each phase and analysis of its potential geological impact from a thermodynamic point of view.     

On topographic coupling of surface and internal tides

The problem of the generation of internal tides through the interaction of surface tides with oceanic bottom topography is re-examined, taking into account the horizontal components of the Earth's rotation. It is shown that previous models that have omitted these terms may be readily extended to include them, and changes in the magnitude and character of the barotropic to baroclinic conversion are estimated. For semi-diurnal tides the energy conversion is increased, but only by about 2%. However, the character of the waves differs at high latitudes, where the phase and location of the wave energy may change by as much as 14%. Accordingly, inclusion of these terms is recommended in future studies with these models.     

Change of multifractal thermal characteristics in the western Philippine sea upper layer during internal wave-soliton propagation

The upper layer (above 140 m depth) temperature in the western Philippine Sea near Taiwan was sampled using a coastal monitoring buoy (CMB) with 15 attached thermistors during July 28–August 7, 2005. The data were collected every 10 min at 1, 3, 5, 10, 15, and 20 m using the CMB sensors, and every 15 sec at 15 different depths between 25 m and 140 m. Internal waves and solitons were identified from the time-depth plot of the temperature field. Without the internal waves and solitons, the power spectra, structure functions, and singular measures (representing the intermittency) of temperature field satisfy the power law with multi-scale characteristics at all depths. The internal waves do not change the basic characteristics of the multifractal structure. However, the internal solitons change the power exponent of the power spectra drastically, especially in the low wave number domain; they also break down the power law of the structure function and increase the intermittency parameter. The physical mechanisms causing these different effects need to be explored further.     

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.     

Tritium profiles in the Weddell Sea

Tritium data were collected between 1985 and 1987 on several cruises of the German research icebreaker “Polarstern” to the Weddell Sea. Maximum tritium concentrations in the surface waters are of the order of 200 mTU. The minimum values observed in the Weddell Sea Deep Water at about 1000 m depth are about 15–40 mTU. The bottom waters show tritium concentrations of about 70–100 mTU in the central gyre, increasing to about 120 mTU in the northwestern corner of the Weddell Sea. The overflowing Ice Shelf Water observed on the continental slope west of the Filchner Depression has tritium concentrations close to those of the surface waters, indicating rapid renewal of this water mass. The data reflect the rapid renewal of the bottom waters in the northwestern corner of the Weddell Sea and the mixing of bottom water from this boundary current into the bottom waters of the central Weddell Gyre.