Beach and nearshore facies: Southeast Australia     

A.D Short 《Marine Geology》1984,60(1-4):261-282

The morphology, texture and facies sequence on seven sand beaches, located in low, moderate and high wave energy, microtidal environments in southern Australia were investigated using box coring and Scuba observations. Systematic variation in facies occur both within and between the beaches. Low-energy reflective beaches are limited in lateral and vertical extent and in facies to beach laminations separated by coarse step deposits from finer nearshore cross-lamination facies. Moderate-energy intermediate beaches characterised by rip circulation possess increasingly wider surfzones with ridge and runnel and bar-trough facies separating the beach and step facies from the more extensive nearshore sequence. High-energy dissipative beaches may have 500 m wide surfzones containing multiple bar-trough topography. Fine beach laminations with backwash structures grade into 4–5 m thick bar-trough sequences then the extensive nearshore facies. As wave energy increases from low (H_b < 1 m) to high (H_b > 2.5 m) the vertical extent of the beach to nearshore sequence increases from <10 m to approximately 30 m, and the width from 100 m to several kilometres. Consequently one would expect higher-energy paleo-beach sequences to be represented more by diagonal than vertical facies sequences.  相似文献   

Isotope ratios of Pb/Pb in eelgrass, Zostera marina, indicate sources of Pb in an estuary     

H. M. Hoven  H. E. Gaudette  F. T. Short   《Marine environmental research》1999,48(4-5)

We deployed hydroponic eelgrass, Zostera marina L., to test its use as a sentinel accumulator and indicator of the source of water-borne lead (Pb) contamination in the marine environment. Eelgrass was deployed unrooted in the water column in the vicinity of the Portsmouth Naval Shipyard, located on Seavey Island in Portsmouth Harbor of New Hampshire and Maine, offshore from seepage sites near the Jamaica Island landfill (JIL). Deployed eelgrass, water samples from seepage sites, and sediment from the deployment sites were analyzed for Pb concentration and stable Pb isotopic composition. Isotopic composition was used to distinguish recent anthropogenic Pb inputs from background Pb in the estuary. Isotope ratios indicated that two groundwater seeps were a source of recent anthropogenic Pb (i.e. industrial Pb from the landfill) to Jamaica Cove. The eelgrass that showed the strongest presence of industrial Pb (having the lowest ²⁰⁶Pb/²⁰⁷Pb) was closest to a high volume seep that drained from the JIL and had a similar isotope signature as well as elevated Pb concentrations. These data confirm a source of water-borne industrial Pb in the estuary and show that eelgrass can function as a sentinel accumulator of Pb from anthropogenic sources.  相似文献   

Rapid shoreline progradation followed by vertical foredune building at Pedro Beach,southeastern Australia     

Thomas S.N. Oliver  Toru Tamura  Andrew D. Short  Colin D. Woodroffe 《地球表面变化过程与地形》2019,44(2):655-666

At Pedro Beach on the southeastern coast of Australia a series of foredune ridges provides an opportunity to explore the morphodynamic paradigm as it applies to coastal barrier systems using optically stimulated luminescence (OSL) dating, ground penetrating radar (GPR) and airborne LiDAR topography. A series of sandy dune-capped ridges, increasing in height seawards, formed from c. 7000 years ago to c. 3900 years ago. During this time the shoreline straightened as the embayment filled and accommodation space for Holocene sediments diminished. Calculation of Holocene sediment accumulation above mean sea level utilising airborne LiDAR topography shows a decline in average sediment supply over this time period coupled with a decrease in shoreline progradation rate from 1.2 m/yr to 0.38 m/yr. The average ridge ‘exposure lifetime’ during this period increases resulting in higher ridges as dune-forming processes have longer to operate. Increasing exposure to wave and wind energy also appears to have resulted in higher ridges as the sheltering effect of marginal headlands was diminished. An inherited disequilibrium shoreface profile will drive onshore accumulation of sandy sediments forming a prograded barrier; however, if there is no longer ‘accommodation space’ for sediment, this will be an overriding factor causing the cessation of progradation, as occurred c. 3900 years ago at Pedro Beach. Excess sediment in the nearshore zone after 3900 years ago may have been moved northward to nourish downdrift beaches in the compartment. A high outer foredune has formed through vertical accretion after 500 years ago, evidenced by GPR subsurface structures and OSL ages, with a distinct period of vertical and lee slope accretion and dated to the period 1890–1930 AD. The increased dune sediment transport resulting in foredune building is attributed to recent human disturbance. © 2018 John Wiley & Sons, Ltd.  相似文献   

Semipermeable membrane devices link site-specific contaminants to effects: Part 1 - Induction of CYP1A in rainbow trout from contaminants in Prince William Sound, Alaska   总被引：1，自引：1，他引：0  

Springman KR  Short JW  Lindeberg MR  Maselko JM  Khan C  Hodson PV  Rice SD 《Marine environmental research》2008,66(5):477-486

Extracts from semi-permeable membrane devices (SPMDs) deployed on beaches in Prince William Sound (PWS), Alaska, were used to evaluate if complex contaminant mixtures from different sources can be distinguished by the resulting cytochrome P450 1A (CYP1A) activity in exposed test animals. Deployment sites included canneries, salmon hatcheries, and beaches where lingering oil remains from discharges during the 1964 earthquake or the 1989 Exxon Valdez oil spill. Other sites were selected at random to evaluate region-wide contaminant inputs or were located in salmon streams to evaluate contaminants carried and released by migrating salmon carcasses following reproduction. Following standard deployments of approximately 28 d, an aliquot of the accumulated contaminants was intraperitoneally injected without cleanup into juvenile rainbow trout (Oncorhynchus mykiss). After 2 d and 7 d, the activity of CYP1A was measured by the ethoxyresorufin-o-deethylase (EROD) assay. Exposure to extracts from the oiled sites and one hatchery site with numerous creosote pilings elicited strong EROD responses, whereas fish exposed to salmon stream extracts elicited weak but significant responses during late summer compared to late spring. Responses from the other sites were not significant, indicating contaminants from these sources are unlikely to cause CYP1A induction in resident biota. Rather than simply assessing extant contaminants, this method evaluates the potency of the different sites for bringing about aryl hydrocarbon receptor responses in resident biota.  相似文献   

Accumulation of polycyclic aromatic hydrocarbons by Neocalanus copepods in Port Valdez, Alaska     

Carls MG  Short JW  Payne J 《Marine pollution bulletin》2006,52(11):1480-1489

Sampling zooplankton is a useful strategy for observing trace hydrocarbon concentrations in water because samples represent an integrated average over a considerable effective sampling volume and are more representative of the sampled environment than discretely collected water samples. We demonstrate this method in Port Valdez, Alaska, an approximately 100 km(2) basin that receives about 0.5-2.4 kg of polynuclear aromatic hydrocarbons (PAH) per day. Total PAH (TPAH) concentrations (0.61-1.31 microg/g dry weight), composition, and spatial distributions in a lipid-rich copepod, Neocalanus were consistent with the discharge as the source of contamination. Although Neocalanus acquire PAH from water or suspended particulate matter, total PAH concentrations in these compartments were at or below method detection limits, demonstrating plankton can amplify trace concentrations to detectable levels useful for study.  相似文献   

Assessment and integration of conventional,RTK-GPS and image-derived beach survey methods for daily to decadal coastal monitoring   总被引：1，自引：0，他引：1  

Mitchell D. Harley  Ian L. Turner  Andrew D. Short  Roshanka Ranasinghe 《Coastal Engineering》2011

Coastal monitoring across a broad range of time-scales was recognized in the latest report by the Intergovernmental Panel on Climate Change as key to better understanding the likely impacts of climate change at the coast. A unique and historic coastal monitoring program undertaken at the Collaroy–Narrabeen embayment in south-eastern Australia comprises: 1) 30 years of monthly conventional (Emery method) surveys of five cross-shore profile lines; 2) three years of monthly three-dimensional surveys of the entire embayment using RTK-GPS mounted to an all-terrain vehicle (ATV); and 3) four years of hourly shoreline measurements using coastal imaging technology (ARGUS). This study evaluates the strengths and limitations of conventional, RTK-GPS and image-derived surveys for coastal monitoring at daily to decadal coastal time-scales. High-accuracy RTK-GPS was used to first assess the accuracy of the conventional and image-derived survey methods. The magnitude of daily to decadal coastal variability was then characterized by calculating the temporal semivariogram of the integrated survey dataset. With both measurement errors and the degree of beach variability quantified, the corresponding signal-to-noise ratios (SNR) of each survey method at different time-scales were determined. The value of the simple and cost-effective Emery method was verified by this analysis, with measurement error significantly smaller than the degree of overall beach variability (SNR = 8.4). The accuracy, speed and efficiency of ATV-mounted RTK-GPS meanwhile make it suitable for three-dimensional beach surveys. Image-derived surveys were found to be an effective means of remotely measuring the considerable degree of beach variability identified at time-scales of less than one month. These measurements however become indistinguishable from survey noise (i.e. SNR ≤ 1) when considering typical weekly (or smaller) variations at large distances from the cameras.  相似文献   

Geomorphology from space: A global overview of regional landforms     

Nicholas M. Short  Robert W. Blair Jr. 《国际地球制图》2013,28(4)

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Thermoluminescenge and Uranium‐Thorium chronologies of pleistocene coastal landforms of the Illawarra region,New South Wales     

E. A. Bryant  R. W. Young  D. M. Price  S. A. Short 《The Australian geographer》1990,21(2):101-112

TL determinations of the ages of aeolian sands and U/Th determinations of the ages of crusts on rock platforms in the Illawarra region, especially at Red Point, indicate that these techniques give considerable promise of a major advance in deciphering the Pleistocene coastal record in Australia. The methods of dating are outlined, and problems of laboratory and field interpretation are considered. The longstanding debate as to whether the +2 m level of platforms is modern or is a Pleistocene relict has been resolved for the Illawarra coast, where these platforms can be shown to have been formed during the Last Interglacial high stand of the sea. By inference, the +4 m level must be of at least the same age. The +6 to 7 m level was cut by about 300Ka and may be as old as Pliocene. Four aeolian units at Red Point reworked from nearby barrier beach complexes date from c. 25Ka, 45Ka, 125Ka, and 300 to >400Ka. Reconnaissance surveys and dating indicate that aeolian sands of similar ages occur elsewhere along the New South Wales coast.  相似文献   

The disturbing case of the concentration of power in human geography     

John Rennie Short 《Area》2002,34(3):323-324

The increasing concentration of power in academic disciplines with the introduction of Research Assessment Exercises is noted. The case of human geography in the UK is discussed.  相似文献   

THE CALIBRATION OF A 35mm NON-METRIC CAMERA AND THE INVESTIGATION OF ITS POTENTIAL USE IN PHOTOGRAMMETRY     

T. Short 《The Photogrammetric Record》1992,14(80):313-322

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