Seasonal and spatial heterogeneity of recent sea surface temperature trends in the Caribbean Sea and southeast Gulf of Mexico

Recent changes in ocean temperature have impacted marine ecosystem function globally. Nevertheless, the responses have depended upon the rate of change of temperature and the season when the changes occur, which are spatially variable. A rigorous statistical analysis of sea surface temperature observations over 25 years was used to examine spatial variability in overall and seasonal temperature trends within the wider Caribbean. The basin has experienced high spatial variability in rates of change of temperature. Most of the warming has been due to increases in summer rather than winter temperatures. However, warming was faster in winter in the Loop Current area and the south-eastern Caribbean, where the annual temperature ranges have contracted. Waters off Florida, Cuba and the Bahamas had a tendency towards cooling in winter, increasing the amplitude of annual temperature ranges. These detailed patterns can be used to elucidate ecological responses to climatic change in the region.     

Bolla Bollana boulder beds: A Neoproterozoic trough mouth fan in South Australia?

The Bolla Bollana Formation is an exceptionally thick (ca 1500 m), rift‐related sedimentary succession cropping out in the northern Flinders Ranges, South Australia, which was deposited during the Sturtian (mid Cryogenian) glaciation. Lithofacies analysis reveals three distinct facies associations which chart changing depositional styles on an ice‐sourced subaqueous fan system. The diamictite facies association is dominant, and comprises both massive and stratified varieties with a range of clast compositions and textures, arranged into thick beds (1 to 20 m), representing stacked, ice‐proximal glaciogenic debris‐flow deposits. A channel belt facies association, most commonly consisting of normally graded conglomerates and sandstones, displays scour and fill structure of ca 10 m width and 1 to 3 m depth: these strata are interpreted as channelized turbidites. Rare mud‐filled channels in this facies association bear glacially striated lonestones. Finally, a sheet heterolithics facies association contains a range of conglomerates through sandstones to silty shales arranged into clear, normally graded cycles from the lamina to bed scale. These record a variety of non‐channelized turbidites, probably occupying distal and/or inter‐channel locations on the subaqueous fan. Coarsening and thickening‐up cycles, capped by dolomicrites or mudstones, are indicative of lobe build out and abandonment, potentially as a result of ice lobe advance and stagnation. Dropstones, recognized by downwarped and punctured laminae beneath pebbles to boulders in shale, or in delicate climbing ripple cross‐laminated siltstones, are clearly indicative of ice rafting. The co‐occurrence of ice‐rafted debris and striated lonestones strongly supports a glaciogenic sediment source for the diamictites. Comparison to Pleistocene analogues enables an interpretation as a trough mouth fan, most probably deposited leeward of a palaeo‐ice stream. Beyond emphasizing the highly dynamic nature of Sturtian ice sheets, these interpretations testify to the oldest trough mouth fan recorded to date.     

Glaciation and deglaciation of the Libyan Desert: The Late Ordovician record

Detailed outcrop studies at the flanks of Al Kufrah Basin, Libya, reveal the nature of glacially-related sedimentation and post-depositional deformation styles produced in association with the Late Ordovician glaciation, during which ice sheets expanded northward over North Africa to deposit the Mamuniyat Formation. At the SE basin flank (Jabal Azbah), the Mamuniyat Formation is sand-dominated, and incises interfingering braidplain and shallow marine deposits of the Hawaz Formation. The glacially-related sediments include intercalations of mud-chip bearing tabular sandstones and intraformational conglomerates, which are interpreted as turbidite and debrite facies respectively. These record aggradation of an extensive sediment wedge in front of a stable former ice margin. An increase in mudstone content northward is accompanied by the occurrence of more evolved turbidites. A widespread surface, bearing streamlined NW–SE striking ridges and grooves, punctuates this succession. The structures on the surface are interpreted to have formed during a regional north-westward ice advance. Above, siltstones bearing Arthrophycus burrows, and Orthocone-bearing sandstones beneath tidal bars testify to glaciomarine conditions for deposition of the underflow deposits beneath. By contrast, the northern basin margin (Jabal az-Zalmah) is appreciably different in recording shallower water/paralic sedimentation styles and major glaciotectonic deformation features, although facies analysis also reveals northward deepening. Here, a siltstone wedging from 8 to 50 m toward the north was deposited (lower delta plain), succeeded by climbing ripple cross-laminated sandstones up to 60 m in thickness (distal through proximal delta mouth bar deposits) with occasional diamictite interbeds. These rocks are deformed by thrusts and > 50 m amplitude fault-propagation folds, the deformation locally sealed by a diamictite then overlain by conglomeratic lag during ultimate deglaciation. Integrating observations from both basin margins, a model of fluvial-dominated delta systems feeding a pulsed debrite and turbidite fan system in a shallow proglacial shelf is proposed.     

An overview of developments and applications of oceanographic radar networks in Asia and Oceania countries

More than 110 radar stations are in operation at the present time in Asia and Oceania countries, which is nearly half of all the existing radar stations in the world, for purposes related to marine safety, oil spill response, tsunami warning, coastal zone management and understanding of ocean current dynamics, depending mainly on each country’s coastal sea characteristics. This paper introduces the oceanographic radar networks of Australia, China, Japan, Korea and Taiwan, presented at the 1st Ocean Radar Conference for Asia (ORCA) held in May 2012, Seoul, Korea, to share information about the radar network developments and operations, knowledge and experiences of data management, and research activity and application of the radar-derived data of neighbouring countries. We hope this overview paper may contribute as the first step to promotion of regional collaborations in the radar observations and data usages and applications in order to efficiently monitor the coastal and marginal sea waters along the western Pacific Ocean periphery.     

On the application of HF ocean radar to the observation of temporal and spatial changes in wind direction

The application of a 30-MHz narrow-beam ground-wave ocean radar to the observation of wind directions is described. It is found that thecos^{s} (theta/2)model for wind-wave directions does not apply in a specific case of shallow water where swell waves are behaving nonlinearly. To experimentally extract unambiguous wind directions from this model requires sampling three different beam angles simultaneously. In practice some time and space stationarity is assumed. Detailed analysis in time and space reveals structure in the transition of the cold front from sea to land which, although unexpected, agrees with coastline observations where they are available. The nature of the structure is only briefly discussed. The response of thelambda = 5-m wind waves to the frontal change was two orders of magnitude faster than time constants for similar events previously modeled using pitch-and-roll buoy data. This discrepancy needs to be reconciled before lower frequency radars can be used without ground truth for wind-direction changes.     

Evolution of Mesozoic fluvial systems along the SE flank of the West Siberian Basin, Russia

The Mesozoic stratigraphy in the subsurface of the West Siberian Basin contains prolific hydrocarbon accumulations, and thus the depositional environments of marine and marginal marine Jurassic and Cretaceous age sediments are well-established. However, no information is currently available on strata of equivalent age that crop out along the SE basin margin in the Mariinsk–Krasnoyarsk region, despite the potential of these exposures to supply important information on the sediment supply routes into the main basin. Detailed sedimentological analysis of Jurassic–Cretaceous clastic sediments, in conjunction with palaeo-botanical data, reveals five facies associations that reflect deposition in a range of continental environments. These include sediments that were deposited in braided river systems, which were best developed in the Early Jurassic. These early river systems infilled the relics of a topography that was possibly inherited from earlier Triassic rifting. More mature fluvial land systems evolved in the Mid to Late Jurassic. By the Mid Jurassic, well-defined overbank areas had become established, channel abandonment was commonplace, and mudrocks were deposited on floodplains. Coal deposition occurred in mires, which were subject to periodic incursions by crevasse splay processes. Cretaceous sedimentation saw a renewed influx of sand-grade sediment into the region. It is proposed that landscape evolution throughout the Jurassic was driven simply by peneplanation rather than tectonic processes. By contrast, the influx of sandstones in the Cretaceous is tentatively linked to hinterland rejuvenation/ tectonic uplift, possibly coeval with the growth of large deltaic clinoform complexes of the Neocomian in the basin subsurface.     

Thermal Treatment of Eight CVOC Source Zones to Near Nondetect Concentrations

In situ thermal desorption (ISTD) was used for the treatment of eight separate source zones containing chlorinated solvents in a tight loess (silt/clay) above the water table. The source areas were as much as 365 m (1200 feet) apart. A target volume of 38,200 m³ (49,950 cubic yards) of subsurface material to a depth of 9.1 m (30 feet) was treated in a period of 177 days. Energy was delivered through 367 thermal conduction heater borings, and vapors were extracted from 68 vertical vacuum wells. A vapor extraction and capture system, including a surface cover and vertical vacuum wells next to heater borings, provided for effective pneumatic control and capture of the chlorinated volatile organic compound (CVOC) vapors. A central treatment system, based on condensation and granular activated carbon filtration, was used to treat the vapors. Approximately 5675 kg (12,500 pounds) of contaminants was recovered in the extracted vapors. Forty-seven soil samples were used to document remedial performance. Based on these, the concentrations of the target contaminants were reduced to below the target remedial goals in all eight areas, typically with concentrations below 0.01 mg/kg in locations that had had CVOC concentrations higher than 1000 mg/kg. Turn-key costs for the thermal remediation were $3.9 million, and the unit treatment cost, including all utilities, was $103 per cubic meter treated ($79 per cubic yard).     

The production and analysis of transmission ionograms

A transmission ionogram gives the group delay for radio pulses transmitted vertically through the ionosphere, as the radio frequency is varied. These virtual height curves may also be produced from fixed-frequency observations on orbiting satellites. Analysis of such records can give the thickness of the peak of the ionosphere, a quantity not readily obtained by other techniques. Using the ground reflection trace on topside ionograms, a rapid two-parameter analysis gives the peak thickness to better than 10 per cent.     

Improving fisheries management in New Zealand: Developing dialogue between fisheries science and management (FSM) and ecosystem science and management (ESM)

This paper attempts to overcome the dichotomy between the broadly different and largely separate fisheries science and management (FSM) and ecosystem science and management (ESM) knowledge systems that characterise the international literature and are found in fisheries management practice in different countries. The paper argues that the construction of a heuristic we term the fisheries problematic, around issues and contexts, reveals the breadth of international fisheries management concerns and the variety of contexts in which these concerns are being faced. Adopting a political economy informed nature-society approach the paper considers ecological and socio-economic processes in their institutional settings in an attempt to shift from the either/or arguments around fish or ecosystems found in the FSM or ESM literatures to investigation that is grounded in understandings of the historically and geographically specific trajectories of fisheries related interactions and understandings of how knowledge about the trajectories and their interactions is fashioned. Drawing on recent conceptual innovations in the field, the paper develops a matrix-centred approach to explore ecological, industry, community and policy domains in New Zealand’s Quota Management System (QMS) and Individual Transferable Quota (ITQ) fisheries management regime. The extended framework prioritises scrutiny of the interaction amongst the four domains, as a strategy to help develop institutional frameworks that facilitate behaviours that are societally inclusive. The paper offers three conclusions. First, the landscape of New Zealand fisheries issues is very much a product of the contingent interaction of the QMS, a management regime designed around the principles of a FSM approach and laid down in a neo-liberal political environment and Maori aspirations encompassing the fisheries sector. Second, the conceptual mapping of FSM and ESM perspectives over New Zealand’s fisheries management experience highlights that a number of management issues have been down played by the commitment to FSM, a situation that has led to on-going tensions between commercial, recreational and customary stakeholders regarding fisheries management. Put another way, there is more to running a sustainable fishery (as defined in the Fisheries Act 1996) than QMS and other tools and dialogue about the development of these should be a priority. Third and more generally, improved dialogue on fisheries questions is likely to be most expeditiously advanced by studies that explicitly conceptualise and contextualise ecological and socio-economic processes and their institutional arrangements.