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Investigates the scope and limits of optical remote sensing instruments for spectral discrimination of benthic communities on the Great Barrier Reef. Advantages of hyperspectral instruments in comparison to broadband multispectral sensors; Characteristics of remote sensing sensors used in model simulations; Differences between simulated upwelling radiance spectra.

The levels of trace elements in whole blood and plasma have been widely used for assessing nutritional status and monitoring exposure and can vary widely in populations from different geographical regions. In this study, whole blood samples ( n = 120) and plasma samples ( n = 120) were obtained from healthy donors attending the Red Cross Blood Bank (Queensland Red Cross Blood Service), which provided information for age and sex. There were 71 males (age range: 19-73 years) and 49 females (age range: 18-72 years) for whole blood samples, and 59 males (age range: 19-81 years) and 61 females (age range: 19-73 years) for plasma samples. The main aim of the study was to provide information on blood reference levels of 21 trace elements (Ag, Al, As, Bi, Br, Cd, Co, Cr, Cu, Hg, I, Mn, Mo, Ni, Pb, Sb, Se, Tl, U, V, Zn) in Queensland. The study also aimed to assess differences in trace element blood levels between males and females and the effect of age. The trace element levels in blood samples were analysed using inductively coupled plasma mass spectrometry (ICP-MS) and the standard reference materials of Seronorm (Trace Elements Whole Blood) and UTAK (Trace Elements Serum) were used for quality control and assurance. The study found wide variations of trace element levels in whole blood and plasma, and generally the levels were comparable to other countries. No detectable levels were found for Bi, Cr, U and V in whole blood, but V levels were found in plasma samples. There were significant differences between males and females for whole blood Cu ( p < 0.001), I ( p = 0.009), Tl ( p = 0.016) and Zn ( p = 0.016). Significant differences were also found for plasma Cu ( p < 0.001) and Se ( p = 0.003) between males and females. There were trends of increased levels of blood Pb, Se and Zn with age. The study has provided further information on a wide range of trace elements in blood as reference levels for Queensland and Australia which are currently lacking.

During colour signalling in aquatic environments, the colour of the ambient light, the background against which signals are viewed and signal transmission through the environment can all have profound impacts on the efficacy of a given signal. In colour-polymorphic species, where alternative morphs persist owing to a balance in the natural and sexual selection for each, changes to the visual context can have large effects on the local success and relative abundance of competing phenotypes. The ornate rainbowfish, Rhadinocentrus ornatus, is composed of populations that vary in the relative frequency of red and blue individuals, and inhabit sites that vary in water transmittance from clear (white) to heavily tannin-stained (red-shifted). Using spectroradiometry, we measured the downwelling and sidewelling irradiance, bank radiance and water transmittance of 10 R. ornatus habitats. We found that the relative local abundance of each morph was predicted not by water transmittance but by chromatic differences between the vertical (downwelling light) and horizontal (bank colour) components of the habitat. This visual habitat geometry should increase contrast between the colour signal and background, with large potential to influence the strength of natural and sexual selection in this system.

Various natural and anthropogenic processes influence heavy metal concentrations within estuaries. In situ, time-integrated DGT measurements made over concurrent tidal phases found significantly higher concentrations of Cu (probability p=0.017), Zn (p=0.003) and Ni (p=0.003) during the flood phase, because the incoming tide passes several point sources. DGT-reactive Cu concentrations significantly decreased with increased tidal-flushing and vice versa within a marina (correlation r=-0.788, p=0.02). DGT measurements also recorded significant increases in Cu (4 out of 4 sites, p<0.001) and Zn (3 out of 4 sites, p< or =0.015) after a 24 mm rainfall event. Finally, DGT-reactive Cu increased significantly (p<0.001) during peak boating times, due to increased numbers of Cu-antifouled boats. This study demonstrates that, with judicious selection of deployment times, DGT measurements enable changes in heavy metal concentrations to be related to various cycles and events within estuaries.

Animal color pattern phenotypes evolve rapidly. What influences their evolution? Because color patterns are used in communication, selection for signal efficacy, relative to the intended receiver's visual system, may explain and predict the direction of evolution. We investigated this in bowerbirds, whose color patterns consist of plumage, bower structure, and ornaments and whose visual displays are presented under predictable visual conditions. We used data on avian vision, environmental conditions, color pattern properties, and an estimate of the bowerbird phylogeny to test hypotheses about evolutionary effects of visual processing. Different components of the color pattern evolve differently. Plumage sexual dimorphism increased and then decreased, while overall (plumage plus bower) visual contrast increased. The use of bowers allows relative crypsis of the bird but increased efficacy of the signal as a whole. Ornaments do not elaborate existing plumage features but instead are innovations (new color schemes) that increase signal efficacy. Isolation between species could be facilitated by plumage but not ornaments, because we observed character displacement only in plumage. Bowerbird color pattern evolution is at least partially predictable from the function of the visual system and from knowledge of different functions of different components of the color patterns. This provides clues to how more constrained visual signaling systems may evolve.

The Paradise whiptail (Pentapodus paradiseus) has distinct reflective stripes on its head and body. The reflective stripes contain a dense layer of physiologically active iridophores, which act as multilayer reflectors. The wavelengths reflected by these stripes can change from blue to red in 0.25 s. Transmission electron microscopy revealed that the iridophore cells contain plates that are, on average, 51.4 nm thick. This thickness produces a stack, which acts as an ideal quarter-wavelength multilayer reflector (equal optical thickness of plates and spaces) in the blue, but not the red, region of the spectrum. When skin preparations were placed into hyposmotic physiological saline, the peak wavelength of the reflected light shifted towards the longer (red) end of the visible spectrum. Hyperosmotic saline reversed this effect and shifted the peak wavelength towards shorter (blue/UV) wavelengths. Norepinephrine (100 micromol l(-1)) shifted the peak wavelength towards the longer end of the spectrum, while adenosine (100 micromol l(-1)) reversed the effects of norepinephrine. The results from this study show that the wavelength changes are elicited by a change of approximately 70 nm in the distance between adjacent plates in the iridophore cells.