18 research outputs found
Recollections of a fire insurance man, including his experience in U.S. Navy (Mississippi squadron) during the Civil War,
No full textMode of access: Internet
Modelling accumulation of marine plastics in the coastal zone; what are the dominant physical processes?
No full textAnthropogenic marine debris, mainly of plastic origin, is accumulating in estuarine and coastal environments around the world causing damage to fauna, flora and habitats. Plastics also have the potential to accumulate in the food web, as well as causing economic losses to tourism and sea-going industries. If we are to manage this increasing threat, we must first understand where debris is accumulating and why these locations are different to others that do not accumulate large amounts of marine debris. This paper demonstrates an advection-diffusion model that includes beaching, settling, resuspension/re-floating, degradation and topographic effects on the wind in nearshore waters to quantify the relative importance of these physical processes governing plastic debris accumulation. The aim of this paper is to prioritise research that will improve modelling outputs in the future. We have found that the physical characteristic of the source location has by far the largest effect on the fate of the debris. The diffusivity, used to parameterise the sub-grid scale movements, and the relationship between debris resuspension/re-floating from beaches and the wind shadow created by high islands also has a dramatic impact on the modelling results. The rate of degradation of macroplastics into microplastics also have a large influence in the result of the modelling. The other processes presented (settling, wind drift velocity) also help determine the fate of debris, but to a lesser degree. These findings may help prioritise research on physical processes that affect plastic accumulation, leading to more accurate modelling, and subsequently management in the future
Designing marine reserve networks to mitigate larval dispersal volatility with the connectivity portfolio effect
No full textContext
Marine reserve networks designed to enhance larval dispersal provide important biodiversity benefits. Designs are commonly based on time-averaged means of dispersal estimates. It is unclear whether they capture the connectivity portfolio effect, by which temporal variation in individual reserve performance is buffered by the entire network.
Objectives
To evaluate the implications of dispersal variability and derive general rules for network design.
Methods
We modelled larval dispersal of four commercially important reef species for 20 years in Southeast Sulawesi, Indonesia. We built reserve network scenarios informed by temporal dispersal as either an interannual mean or dispersal for individual years. We then evaluated reserve network performance.
Results
Plectropomus leopardus and Siganus canaliculatus experienced higher variability in interannual larval flow compared to Lutjanus malabaricus and Octopus vulgaris. We discover that using a single time-averaged mean dispersal estimate can create subpar reserve networks in highly variable systems. Mean dispersal was suitable for less variable species such as O. vulgaris, but not for more variable species where high larval flow was not protected over time. By explicitly identifying reefs contributing a high amount of larval flow in each of the 20 years, we were able to improve network designs and provide a more consistent protection of larval supply over time.
Conclusions
We develop methods to improve network performance by protecting reefs with high larval flow contribution across years. The steps outlined here illustrate how information from multitemporal connectivity datasets can help inform a spatial prioritisation framework to accommodate larval dispersal volatility
Prioritising investment in kelp forest restoration: A spatially explicit benefit-cost analysis in southern Australia
No full textKelp forests are globally significant ecosystems providing critical ecosystem services, including fish production, nutrient cycling, carbon sequestration, and recreational uses. However, widespread degradation caused by anthropogenic pressures has led to significant declines in kelp forests, necessitating cost-effective restoration strategies. This study performs a spatially explicit benefit-cost analysis of kelp forest restoration in southern Australia to explore how variations in costs and benefits can inform prioritisation of restoration strategies. Costs of ecosystem restoration were calculated based on the time to cull overabundant sea urchins from each location and for active kelp restoration costs. We found that investing in kelp forest restoration at the broad-scale (3,291 ha) returns a positive benefit-cost ratio of 1.10 (where 1.0 is break-even). There was substantial site-specific variation in the benefit-cost ratio (0.33 to 3.4), driven by variation in predicted kelp biomass and thus nitrogen storage benefits (105,000 /ha). For culling costs, this varied based on urchin density, the depth (dive time) and travel time to the site. Given this variation, we considered another scenario where only the reefs that returned a positive benefit-cost ration were restored (1,221 ha), which would deliver 43.9 million and would result in a benefit-cost ratio of 2.10. This research demonstrates how spatial prioritisation can guide investments in marine ecosystem restoration to maximise return on investment. However, while kelp restoration proves beneficial, realising its potential will require robust funding mechanisms (perhaps via market-based incentives), which are currently lacking
Memorial on Parade : celebrating from 1925-1961
No full textMemorial on Parade Celebrating 1925-1961Preface / James Downey -- The 30s. Audrey Ralph Lee -- Grace Layman -- David Pitt -- Owen Steele -- The 40s. Alison O'Reilly Feder -- Harry Cuff -- Elizabeth Carter Brettell Gibson -- John Peters Henderson -- Janet Story -- Fred Vivian -- A.D. Newbury -- Herman Blackwood -- Douglas B. Sheppard -- Cec Vivian -- Bill Abraham -- Chesley Blackwood -- Jean Lewis Coombs -- Madeline Randell Critchell -- Maxine Titford Vivian -- Nix Wadden -- Mary Lyons Hicks -- Jasper Lake -- Llewellyn Parsons -- Rex Parsons -- Wilbur Sparkes -- Melvie Roberts Miller -- Sheila Kelly Gushue - Eric Spurrell -- Lester Taylor -- David Jeans -- The 50s. Nelson Bennett -- Gerald Bowering -- Hubert Harnett -- Hilda Chaulk Murray -- Margaret Clouter and Ruth Hobbs Hobsdon -- Marjorie V. Reynolds -- Ada E. Simms -- Ron Clarke -- Anna Curren -- Harold Hollett -- John Kean -- Cecil H. Parsons -- David J. Spurrell -- Doug Squires -- Isabel Hennessey Farrar -- Harold Williams -- Arthur Moore -- Edward C. Moulton -- Bill Rompkey -- Bernard Adey -- Patricia Austin Rogers -- Don Clarke -- Shirley Earle Clarke -- Clarence Brown Dewling -- Trudy Gosse -- Grace Hiscock Hollett -- Dolores O'Toole Bedingfield -- Allenby T. Pinhorn -- Graham Skanes -- Edison Trask -- John Byrne -- Douglas Chaytor -- Maxine Guzzwell Dawe -- John MacGillivray -- Alice Green Moulton -- Robin MacGillivray Fewer -- Angela Mills Sullivan -- Frankie O'Neill -- Carolyn Pike Rompkey -- Elizabeth Russell Miller -- Myrle Vokey -- Linda Winter Barrett -- Marina Bishop Bannister -- Gerald Bannister -- Edith Bursey Edgecombe -- Gordon E. Cooper -- Tom Curran -- Max Haines -- Shirley Morris Cooper -- Kevin Pardy -- Molly O'Driscoll-Croke -- Tom Rissesco -- Carl M. Stevenson -- Florence Maud Newhook Pinhorn -- Elsie Pretty Watson -- Shannon Ryan -- David Allen Vardy -- Leo Barry -- Don Blackmore -- Austin Greening -- Judi Earle Haines -- Don Rideout -- Eric K. Jerrett -- Wilson Callan -- Marion Davis -- Tom Hallett and Jean Wornell Hallett -- Celeste Pomeroy Hawkins -- Frank Hawkins -- Paul Patey -- Wallace Pinhorn -- C. Leslie Dominy -- Marianne Fougere Rissesco -- Joan Lester Chapman -- David W. Riche -- Edgar Williams -- Laura Higdon Williams -- Epigraph Liz Scammell ReynoldsCover titl
Plastic pollution in the coastal environment: current challenges and future solutions
No full textThe dependence on plastic materials for modern life has led to an increase of plastic waste in coastal systems. Microplastics (plastics < 5. mm in size) in particular, have induced alarm among scientific and management bodies as an emerging marine and coastal contaminant. Recent studies suggest that these small plastic particles are ubiquitous in the marine system, as they have been recorded in every coastal and marine habitat around the world. The presence of microplastics in the environment has been shown to have negative consequences for many marine wildlife species, such as marine birds, turtles, and fish. To mitigate the harm caused by plastic pollution, it is essential to understand the life cycle of plastic products, beginning with plastic use and disposal, to the arrival at coastal marine environments. Therefore, this chapter focuses on the issue of plastic pollution in the coastal environment and reviews the current knowledge base on sources, dispersal, accumulation, and most importantly solutions for the problem of plastic pollution. This chapter also discusses and gives examples of current initiatives to reduce the plastic load, including the circular economy approach, and other successful campaigns around the world. Lastly, it discusses the importance of the behavioral, social, and economic changes needed to reduce plastic demand and use for lasting systematic solutions
Modelling the fate of marine debris along a complex shoreline: lessons from the Great Barrier Reef
No full textThe accumulation of floating anthropogenic debris in marine and coastal areas has environmental, economic, aesthetic, and human health impacts. Until now, modelling the transport of such debris has largely been restricted to the large-scales of open seas. We used oceanographic modelling to identify potential sites of debris accumulation along a rugged coastline with headlands, islands, rocky coasts and beaches. Our study site was the Great Barrier Reef World Heritage Area that has an emerging problem with debris accumulation. We found that the classical techniques of modelling the transport of floating debris models are only moderately successful due to a number of unknowns or assumptions, such as the value of the wind drift coefficient, the variability of the oceanic forcing and of the wind, the resuspension of some floating debris by waves, and the poorly known relative contribution of floating debris from urban rivers and commercial and recreational shipping. Nevertheless the model was successful in reproducing a number of observations such as the existence of hot spots of accumulation. The orientation of beaches to the prevailing wind direction affected the accumulation rate of debris. The wind drift coefficient and the exact timing of the release of the debris at sea affected little the movement of debris originating from rivers but it affected measurably that of debris originating from ships. It was thus possible to produce local hotspot maps for floating debris, especially those originating from rivers. Such modelling can be used to inform local management decisions, and it also identifies likely priority research areas to more reliably predict the trajectory and landing points of floating debris
Visual exploratory activity and resultant behavioural analysis of youth midfield soccer players
No full textThe purpose of this study was to examine the effects of visual exploratory activity, prior to receiving the ball in the middle third of the pitch, on the actions of youth midfield soccer players. The visual exploratory activity of three youth central midfield players was examined using a player cam approach, which in turn, was related to each player’s actions, after receiving the ball, through the use of a wide angle perspective. SportsCode Elite software was used to analyse all player actions post-event. Players participated in five training games, each 20 minutes in duration. The player’s actions were divided into five themes: (1) maintaining possession, (2) loss of possession, (3) field location of maintained possessions (4) defensive pressure, and, (5) turning. Associations between visual exploratory activity and each of the resultant behavioural themes were examined using a chi-squared test (p<0.05). The findings of the study revealed that the players performed more forward passes, executed more passes into the attacking half, performed more turns when opportunities arose, and experienced less defensive pressure when performing visual exploratory activity prior to receiving the ball (p<0.01). There is evidence to suggest that coaches should encourage players to perform visual exploratory activity prior to receiving possession of the football. Moreover, coaches should be acutely aware that visual exploratory activity can influence the technical and tactical aspects of performance, and, consequently, this aspect should be considered an important facet to aid player development
Plastic pollution and small juvenile marine Turtles: A potential evolutionary trap
No full textThe ingestion of plastic by marine turtles is now reported for all species. Small juvenile turtles (including post-hatchling and oceanic juveniles) are thought to be most at risk, due to feeding preferences and overlap with areas of high plastic abundance. Their remote and dispersed life stage, however, results in limited access and assessments. Here, stranded and bycaught specimens from Queensland Australia, Pacific Ocean (PO; n = 65; 1993–2019) and Western Australia, Indian Ocean (IO; n = 56; 2015–2019) provide a unique opportunity to assess the extent of plastic (> 1mm) ingestion in five species [green (Chelonia mydas), loggerhead (Caretta caretta), hawksbill (Eretmochelys imbricata), olive ridley (Lepidochelys olivacea), and flatback turtles (Natator depressus)]. In the Pacific Ocean, high incidence of ingestion occurred in green (83%; n = 36), loggerhead (86%; n = 7), flatback (80%; n = 10) and olive ridley turtles (29%; n = 7). There was an overall lower incidence in IO; highest being in the flatback (28%; n = 18), the loggerhead (21%; n = 14) and green (9%; n = 22). No macroplastic debris ingestion was documented for hawksbill turtles in either site although sample sizes were smaller for this species (PO n = 5; IO n = 2). In the Pacific Ocean, the majority of ingested debris was made up of hard fragments (mean of all species 52%; species averages 46–97%), whereas for the Indian Ocean these were filamentous plastics (52%; 43–77%). The most abundant colour for both sites across all species was clear (PO: 36%; IO: 39%), followed by white for PO (36%) then green and blue for IO (16%; 16%). The polymers most commonly ingested by turtles in both oceans were polyethylene (PE; PO-58%; IO-39%) and polypropylene (PP; PO-20.2%; IO-23.5%). We frame the high occurrence of ingested plastic present in this marine turtle life stage as a potential evolutionary trap as they undertake their development in what are now some of the most polluted areas of the global oceans
