72 research outputs found
Cayne Layton
No full textPhD candidate at the Institute for Marine and Antarctic Studies (IMAS) at University of Tasmania (UTAS). Working under the supervision of Prof. Craig Johnson and Dr. Jeffrey Wright I am investigating the stability and resilience of Ecklonia radiata kelp forests in Southern Australia
Maria Island mussel and microphytobenthic algal data
No full textMaintenance and Update Frequency: none-plannedStatement: The experimental reefs were constructed from concrete pavers elevated 0.3 m above sandy substratum on a steel frame. The 28 reefs comprised seven different patch sizes (0.12, 0.24, 0.48, 1.08, 1.92, 4.32 and 7.68 m2) crossed with four kelp density treatments (zero (0), low (4.1), medium (8.3) and high (16.6 kelp m-2).
Microphytobenthic algal recruitment were assessed by using microscope slides positioned on the substratum of each reef, deployed from October to November 2015. Recruitment of mussels was assessed using standardised rope fibre habitats positioned on each reef, deployed from May to November 2015.<b>Credit</b><br/>This study was funded by an Australian Research Council Discovery Grant DP130101113; (www.arc.gov.au) awarded to Jeffrey T Wright and Craig R Johnsosn and the Holsworth Wildlife Research Endowment awarded to Cayne LaytonThe recruitment of mussels and microphytobenthic (MPB) algae to 28 experimental artificial reefs supporting different patch sizes and density of kelp (Ecklonia radiata) off Maria Island, Tasmania. The recruitment of mussels was assessed using rope fibre habitats, and the recruitment of MPB algae was assessed using microscope slides, positioned across the artificial reef and collected in November 2015. These data were collected to examine how the patch size and density of kelp influences the establishment of MPB algae and mussels
Resilience and stability of Ecklonia radiata kelp forests: the importance of intraspecific facilitation and patch dynamics
No full textKelp forests dominate coastal environments in temperate and subpolar latitudes around the world and, much like terrestrial forests, create complex habitats that support diverse and productive food webs. Studies of the resilience and stability of habitat-forming ecosystem engineers such as kelp have typically focussed on the role of external factors such as disturbance. Here, I propose that the stability and resilience of these species are also strongly influenced by internal processes. Such that, changes to the environment caused by engineer species positively affect their own demography (e.g. growth, survivorship), resulting in intraspecific facilitation via an 'environment-engineer' feedback. Ecklonia radiata is the most widespread and abundant habitat-forming kelp in Australasia. Unfortunately, this species is threatened by increasing ocean temperatures, overgrazing, and pollution, and is consequently becoming increasingly patchy and sparse in many locations. Existing research has focussed on understanding how external stressors and disturbances influence the population dynamics of E. radiata, however internal drivers such as the environment-engineer feedback are potentially just as important but remain largely unaddressed. My core aims were to determine (i) how engineering of the local environment by E. radiata changes with patch size, and how this influences environment-engineer feedback on the species' demography, and (ii) how the nature of the feedback influences stability and resilience of E. radiata in the face of increasing habitat fragmentation and degradation. Long-term field experiments confirmed that engineering of abiotic conditions within E. radiata habitats is patch size dependent (Chapter 2), and that reductions in patch size disrupt the recruitment of juvenile E. radiata (Chapter 3). These findings directed the construction of an artificial reef system spanning more than a hectare, and onto which over 500 adult E. radiata were transplanted. Using this unique experimental environment, I found that reductions to patch size and adult kelp density impair microscopic and macroscopic juvenile E. radiata due to a breakdown of ecosystem engineering by adult conspecifics, such that demographic collapse occurs in the absence of sufficient adult E. radiata (Chapter 4). Two key outcomes from these field studies were: (1) the provision of suitable habitat and amelioration of physical stressors via ecosystem engineering by adult E. radiata appears critical to juvenile conspecifics and; (2) formation and development of filamentous turf algae ‚Äö- which inhibit kelp recruitment ‚Äö- is a primary cause and effect of the demographic collapse of E. radiata populations. Ecklonia radiata and turf algae habitats exist as alternative stable states, with each state inhibiting the formation of the other. I developed an innovative laboratory experiment to improve understanding of how turf algae may disrupt the recruitment of E. radiata, and found that turf algae create highly modified chemical conditions in the benthic microenvironments with elevated concentrations of oxygen and pH relative to E. radiata assemblages (Chapter 5). Ultimately, this thesis presents results consistent with the hypothesis that positive environment-engineer feedback facilitates the demography of E. radiata. Moreover, the impaired ability of E. radiata to engineer change due to reductions in patch size cause a breakdown in this intraspecific facilitation, leading too reduced habitat stability and resilience. This work contributes to ecological theories of habitat resilience, facilitation, alternative stable states and ecosystem engineers, and provides insights for the future management, conservation and restoration of critically important kelp forest ecosystems
The financial crisis of 2008 in fixed income markets
No full textWe explore how a relatively small amount of heterogeneous securities created turmoil in financial markets in much of the world in 2007 and 2008. The drivers of the financial turmoil and the financial crisis of 2008 were heterogeneous securities that were hard to value. These securities created concerns about counterparty risk and ultimately created substantial uncertainty. The problems spread in ways that were hard to see in advance. The run on prime money market funds in September 2008 and the effects on commercial paper were an important aspect of the crisis itself and are discussed in some detail.
Ocean resource use: building the coastal blue economy
No full textPublished online: 02 March 2021.Humans have relied on coastal resources for centuries. However, current growth in population and increased accessibility of coastal resources through technology have resulted in overcrowded and often conflicted spaces. The recent global move towards development of national blue economy strategies further highlights the increased focus on coastal resources to address a broad range of blue growth industries. The need to manage sustainable development and future exploitation of both over-utilised and emergent coastal resources is both a political and environmental complexity. To address this complexity, we draw on the perspectives of a multi-disciplinary team, utilising two in depth exemplary case studies in New Zealand and within the Myanmar Delta Landscape, to showcase barriers, pathways and actions that facilitate a move from Business as Usual (BAU) to a future aligned with the Sustainable Development Goals (SDGs) and the UN International Decade of Ocean Science for Sustainable Development 2021-2030. We provide key recommendations to guide interest groups, and nations globally, towards sustainable utilisation, conservation and preservation of their marine environments in a fair and equitable way, and in collaboration with those who directly rely upon coastal ecosystems. We envision a sustainable future driven by conflict mitigation and resolution, where:(i)Change is motivated and facilitated(ii)Coastal ecosystems are co-managed by multiple reliant groups(iii)Networks that maintain and enhance biodiversity are implemented(iv)Decision-making is equitable and based on ecosystem services(v)Knowledge of the marine realm is strengthened-'mapping the ocean of life'(vi)The interests of diverse user groups are balanced with a fair distribution of benefits.Narissa Bax, Camilla Novaglio, Kimberley H. Maxwell, Koen Meyers, Joy McCann, Sarah Jennings, Stewart Frusher, Elizabeth A. Fulton, Melissa Nursey-Bray, Mibu Fischer, Kelli Anderson, Cayne Layton, Gholam Reza Emad, Karen A. Alexander, Yannick Rousseau, Zau Lunn, Chris G. Carte
Respirometry data
No full textColumn headings:fish= fish ID number; treatment= unparasitized (UN), parasitized (P), parasite added (FUN), parasite removed (REM),speed= relative swimming speed in body lengths per second, MO2= oxygen consumption rate in mg oxygen per kilogram per hour
Parasite_ANOVA
No full textColumn headings: Fish= Fish ID; Treatment= unparasitized (UN), parasitized (P), parasite removed (REM), parasite added(FUN); SMR= standard metabolic rate; MMR= maximum metabolic rate; AS= factorial aerobic scope; Ucrit= critical swimming spee
Ectoparasites increase swimming costs in a coral reef fish
No full textEctoparasites can reduce individual fitness by negatively affecting behavioural, morphological and physiological traits. In fishes, there are potential costs if ectoparasites decrease streamlining, thereby directly compromising swimming performance. Few studies have examined the effects of ectoparasites on fish swimming performance and none distinguish between energetic costs imposed by changes in streamlining and effects on host physiology. The bridled monocle bream (Scolopsis bilineatus) is parasitized by an isopod (Anilocra nemipteri), which attaches above the eye. We show that parasitized fish have higher standard metabolic rates (SMRs), poorer aerobic capacities and lower maximum swimming speeds than non-parasitized fish. Adding a model parasite did not affect SMR, but reduced maximum swimming speed and elevated oxygen consumption rates at high speeds to levels observed in naturally parasitized fish. This demonstrates that ectoparasites create drag effects that are important at high speeds. The higher SMR of naturally parasitized fish does, however, reveal an effect of parasitism on host physiology. This effect was easily reversed: fish whose parasite was removed 24 h earlier did not differ from unparasitized fish in any performance metrics. In sum, the main cost of this ectoparasite is probably its direct effect on streamlining, reducing swimming performance at high speeds
Data from: Ectoparasites increase swimming costs in a coral reef fish
No full textEctoparasites can reduce individual fitness by negatively affecting behavioural, morphological and physiological traits. In fishes, there are potential costs if ectoparasites decrease streamlining, thereby directly compromising swimming performance. Few studies have examined the effects of ectoparasites on fish swimming performance and none distinguish between energetic costs imposed by changes in streamlining and effects on host physiology. The bridled monocle bream (Scolopsis bilineatus) is parasitized by an isopod (Anilocra nemipteri), which attaches above the eye. We show that parasitized fish have higher standard metabolic rates (SMR), poorer aerobic capacities and lower maximum swimming speeds than non-parasitized fish. Adding a model parasite did not affect SMR, but reduced maximum swimming speed and elevated oxygen consumption rates at high speeds to levels observed in naturally-parasitized fish. This demonstrates that ectoparasites create drag effects that are important at high speeds. The higher SMR of naturally-parasitised fish does, however, reveal an effect of parasitism on host physiology. This effect was easily reversed: fish whose parasite was removed 24 h earlier did not differ from unparasitized fish in any performance metrics. In sum, the main cost of this ectoparasite is probably its direct effect on streamlining, reducing swimming performance at high speeds
NSW Macrocystis rafting
No full textMaintenance and Update Frequency: none-plannedStatement: Sampling of washed up kelp rafts (i.e. beach rack)Out-of-range observations of significant rafts of giant kelp (Macrocystis pyrifera) washing ashore in southern NSW in winter 2020. <br/><br/>On 9 August 2020, two local marine naturalists on the south coast of New South Wales, Australia noticed a significant amount of a large unfamiliar kelp washed up on a local beach. Following some quick confirmations via phone and email, it was revealed that the unfamiliar seaweed was giant kelp (Macrocystis pyrifera): a species whose closest known populations are ~450 km away to the south (in Tasmania and western Victoria) and whose transport to New South Wales would have required oceanic rafting over several weeks and hundreds of kilometres against the prevailing south-flowing East Australian Current. Subsequent community-led searches over the following days confirmed four more locations of often-substantial amounts of giant kelp wrack, as well as many more anecdotal and unconfirmed accounts
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