The kelp forest ecosystem at Petticoe Wick Bay lat 55 55’N. Long 2 09’W: an ecological study

The sub littoral vegetation at Petticoe Wick Bay Lat 55 55'N. Long 2 09'W. is described using two methods; a classificatory one (of the Zurich-Montpelier School of Phytosociology) and an agglomerative one (the Wisconsin Comparative Ordination Technique). Floristically distinct groups are extracted and discussed. Methods of measuring the net annual production of the dominant kelp Laminaria hyperborea (Gunn)Poslle and its associated epiphytes to assess their performance in relation to depth of submersion are presented and the results discussed. Data on the age structure of the community and infestation levels of Patina pellucida L is presented. The performance of L. hyperborea at three other sites is studied and compared to the results from Petticoe Wick

Using habitat suitability models in an industrial setting: the case for internesting flatback turtles

To predict and manage ecological impacts of anthropogenic activities effectively, an understanding of at-risk species spatial ecology is first required. This is particularly difficult in the marine environment due to limited offshore access and wide-ranging movements of some species. Flatback turtles are a protected species potentially at risk from hazards associated with the resource sector in Australia, yet their at-sea spatial ecology is not well understood. We use habitat suitability modeling to identify environmental variables that influence flatback turtle internesting movement; identify areas of suitable internesting habitat; and determine overlap of identified internesting habitat with resource sector hazards. Internesting movements of 47 female flatback turtles, from five rookeries in the North West Shelf region of Western Australia, were recorded using platform terminal transmitters between 2006 and 2010. Environmental variables including sea surface temperature (SST), bathymetry, magnetic anomalies, distance from coastline, slope, and ruggedness index were combined with the tracking data from each rookery in an ecological niche model. We used the positions of resource sector vessels to represent areas of potential impact from resource sector hazards and identified overlap with suitable internesting habitat areas as a representative of the likelihood of impact. The primary environmental variables that influenced flatback internesting movement were bathymetry, distance from coastline, and SST. Suitable areas of internesting habitat were located in close proximity to many known flatback turtle rookeries across the region. Areas of suitable internesting habitat overlapped resource sector hazards in close proximity to four of the five rookeries and at other known flatback turtle rookeries. The cumulative overlap across the overall study area indicates a high potential for interaction with resource sector hazards, demonstrating the need for regional protection measures in these areas. This study provides a capability for regulators and developers to determine the potential offshore presence of internesting flatback turtles within the region, allowing for protection measures to be targeted appropriately as industrial development continues

QTL influencing growth and wood properties in Eucalyptus globulus

Regions of the genome affecting physical and chemical wood properties (QTL), as well as growth, were identified using a clonally replicated, outbred F2 family (112 genotypes, each with 2 ramets) of Eucalyptus globulus, planted in a field trial in north-west Tasmania. Traits studied were growth (assessed by stem diameter), wood density, cellulose content, pulp yield and lignin content. These traits are important in breeding for pulpwood, and will be important in breeding for carbon sequestration and biofuel production. Between one and four QTL were located for each trait, with each QTL explaining between 9% and 24% of the variation between genotype means. Several QTL for chemical wood properties were co-located, consistent with their high phenotypic correlations, and may reflect pleiotropic effects of the same genes. In contrast, QTL for density and lignin content with overlapping confidence intervals were considered to be due to independent genes, since the QTL effects were inherited from different parents. The inclusion of fully informative microsatellites on the linkage map allowed the determination of homology at the linkage group level between QTL and candidate genes in different pedigrees of E. globulus and different eucalypt species. None of the candidate genes mapped in comparable studies co-located with our major QTL for wood chemical properties, arguing that there are important candidate genes yet to be discovered

Unravelling the photoprotective mechanisms of nature-inspired ultraviolet filters using ultrafast spectroscopy

There are several drawbacks with the current commercially available ultraviolet (UV) filters used in sunscreen formulations, namely deleterious human and ecotoxic effects. As a result of the drawbacks, a current research interest is in identifying and designing new UV filters. One approach that has been explored in recent years is to use nature as inspiration, which is the focus of this review. Both plants and microorganisms have adapted to synthesize their own photoprotective molecules to guard their DNA from potentially harmful UV radiation. The relaxation mechanism of a molecule after it has been photoexcited can be unravelled by several techniques, the ones of most interest for this review being ultrafast spectroscopy and computational methods. Within the literature, both techniques have been implemented on plant-, and microbial-inspired UV filters to better understand their photoprotective roles in nature. This review aims to explore these findings for both families of nature-inspired UV filters in the hope of guiding the future design of sunscreens

Exploring photoprotection in natural ultraviolet filters

Ultraviolet radiation causes a number of deleterious effects on humans and other living organisms. As such, photoprotection is crucial, and whilst humans produce melanin as a natural defence mechanism, this is not usually sufficient. Therefore, alternative photoprotection is required and one way is through the use of sunscreens. The ultraviolet filters currently used within sunscreens have a number of associated drawbacks. As a result, alternative ultraviolet filters are needed and one approach is taking inspiration from nature. This thesis does exactly that as the molecules of interest are a family of natural ultraviolet filters, mycosporines and mycosporine-like amino acids. In this thesis, a bottom-up approach has been adopted to glean insight into the simplest system first and then increasing the complexity of the studied system from a photochemical and photophysical standpoint. In Chapter 2, the cyclohexenone building block of mycosporines was investigated as an extension of previous work. Experimental and computational results determined that the majority of population recovers back to the electronic ground state on ultrafast timescales. As a result, the cyclohexenone core is not as poor of an ultraviolet filter as previously thought. In Chapters 3 and 4, a number of mycosporine-like amino acids were explored spectroscopically and computationally. The results linked the ultrafast dynamics to their unrivalled long-term photostability, thus highlighting the efficiency of the photoprotective mechanism in these molecules. Finally, Chapter 5 took the investigations further by examining a crude extract from Palmaria palmata containing mycosporinelike amino acids in more viscous and restricted surface environments. It was found that the photoprotective mechanism was retained in these environments. Overall, this thesis demonstrates the efficient photon-to-heat conversion capabilities of mycosporine-like amino acids making them ideal candidates as ultraviolet filters. Furthermore, such results can guide the future experiments and chemical design of not only ultraviolet filters in sunscreens but in any field where photon-to-heat conversion is desirable

Reinvestigating the Photoprotection Properties of a Mycosporine Amino Acid Motif

With the growing concern regarding commercially available ultraviolet (UV) filters damaging the environment, there is an urgent need to discover new UV filters. A family of molecules called mycosporines and mycosporine-like amino acids (referred to as MAAs collectively) are synthesized by cyanobacteria, fungi and algae and act as the natural UV filters for these organisms. Mycosporines are formed of a cyclohexenone core structure while mycosporine-like amino acids are formed of a cyclohexenimine core structure. To better understand the photoprotection properties of MAAs, we implement a bottom-up approach by first studying a simple analog of an MAA, 3-aminocyclohex-2-en-1-one (ACyO). Previous experimental studies on ACyO using transient electronic absorption spectroscopy (TEAS) suggest that upon photoexcitation, ACyO becomes trapped in the minimum of an S1 state, which persists for extended time delays (>2.5 ns). However, these studies were unable to establish the extent of electronic ground state recovery of ACyO within 2.5 ns due to experimental constraints. In the present studies, we have implemented transient vibrational absorption spectroscopy (as well as complementary TEAS) with Fourier transform infrared spectroscopy and density functional theory to establish the extent of electronic ground state recovery of ACyO within this time window. We show that by 1.8 ns, there is >75% electronic ground state recovery of ACyO, with the remaining percentage likely persisting in the electronic excited state. Long-term irradiation studies on ACyO have shown that a small percentage degrades after 2 h of irradiation, plausibly due to some of the aforementioned trapped ACyO going on to form a photoproduct. Collectively, these studies imply that a base building block of MAAs already displays characteristics of an effective UV filter