Shadows : Re-visualising the shark. Developing a framework for hybrid photography in the illumination of nonhuman animal and ecological perspectives at Heron Island and Gladstone, Great Barrier Reef

This study investigated how and to what degree “hybrid photography”—the simultaneous use of indexical and fictional properties and strategies— innovates the representation of animals within animalcentric, ecocentric frameworks. Design theory structured this project’s Practice-led, Visual research methodology framework. Grounded theory processes articulated emerging categories of hybrid photography through systematically and comparatively treating animal photography works for reflexive analysis. Design theory then applied and clarified categories, developing practice that re-visualised shark perspectives as new ecological discourse. Shadows, a creative practice installation, realised a full-scale photographic investigation into shark and marine animal realities of a specific environment—Heron Island and Gladstone, Great Barrier Reef—facing ecological crisis from dredging and development at Gladstone Harbour. Works rendered and explored hybrid photography’s capacity for illuminating nonhuman animals, in particular, sharks, and comprise 65% of this project’s weighting. This exegetical paper offers a definition, strategies and evaluation of hybrid photography in unsettling animal perspectives as effective ecological discourse, and comprises 35%.

Nitrogen ecophysiology of Heron Island, a subtropical coral cay of the Great Barrier Reef, Australia

Coral cays form part of the Australian Great Barrier Reef. Coral cays with high densities of seabirds are areas of extreme nitrogen (N) enrichment with deposition rates of up to 1000 kg N ha(-1) y(-1). The ways in which N sources are utilised by coral cay plants, N is distributed within the cay, and whether or not seabird-derived N moves from cay to surrounding marine environments were investigated. We used N metabolite analysis, N-15 labelling and N-15 natural abundance (delta(15)N) techniques. Deposited guano-derived uric acid is hydrolysed to ammonium (NH4+) and gaseous ammonia (NH3). Ammonium undergoes nitrification, and nitrate (NO3-) and NH4+ were the main forms of soluble N in the soil. Plants from seabird rookeries have a high capacity to take up and assimilate NH4+, are able to metabolise uric acid, but have low rates of NO3- uptake and assimilation. We concluded that NH4+ is the principal source of N for plants growing at seabird rookeries, and that the presence of NH4+ in soil and gaseous NH3 in the atmosphere inhibits assimilation of NO3-, although NO3- is taken up and stored. Seabird guano, Pisonia forest soil and vegetation were similarly enriched in N-15 suggesting that the isotopic enrichment of guano (delta(15)N 9.9parts per thousand) carries through the forest ecosystem. Soil and plants from woodland and beach environments had lower delta(15)N (average 6.5parts per thousand) indicating a lower contribution of bird-derived N to the N nutrition of plants at these sites. The aquifer under the cay receives seabird-derived N leached from the cay and has high concentrations of N-15-enriched NO3- (delta(15)N 7.9parts per thousand). Macroalgae from reefs with and without seabirds had similar delta(15)N values of 2.0-3.9parts per thousand suggesting that reef macroalgae do not utilise N-15-enriched seabird-derived N as a main source of N. At a site beyond the Heron Reef Crest, macroalgae had elevated delta(15)N of 5.2parts per thousand, possibly indicating that there are locations where macroalgae access isotopically enriched aquifer-derived N. Nitrogen relations of Heron Island vegetation are compared with other reef islands and a conceptual model is presented.

Overstreetia olsoni n.sp. (Digenea: Zoogonidae) from the Capricorn silverside Atherinomorus capricornensis (Woodland) (Atherindae) off Heron Island, southern Great Barrier Reef

A new species, Overstreetia olsoni, is described from Atherinomorus capricornensis off Heron Island on the Great Barrier Reef off Queensland, Australia. It differs from its only known congener in that the enlarged spines of the circum-oral rows are smaller (

Sand and nest temperatures and an estimate of hatchling sex ratio from the Heron Island green turtle (Chelonia mydas) rookery, Southern Great Barrier Reef

Sand and nest temperatures were monitored during the 2002-2003 nesting season of the green turtle, Chelonia mydas, at Heron Island, Great Barrier Reef, Australia. Sand temperatures increased from similar to 24 degrees C early in the season to 27-29 degrees C in the middle, before decreasing again. Beach orientation affected sand temperature at nest depth throughout the season; the north facing beach remained 0.7 degrees C warmer than the east, which was 0.9 degrees C warmer than the south, but monitored nest temperatures were similar across all beaches. Sand temperature at 100 cm depth was cooler than at 40 cm early in the season, but this reversed at the end. Nest temperatures increased 2-4 degrees C above sand temperatures during the later half of incubation due to metabolic heating. Hatchling sex ratio inferred from nest temperature profiles indicated a strong female bias.

Airborne hyperspectral image data of Heron Reef, Australia

This airborne hyperspectral (19 bands) image data of Heron Reef, Great Barrier Reef, Australia is derived from Compact Airborne Spectrographic Imager (CASI) data acquired on 1st and 3rd of July 2002, latitude -23.45, longitude 151.92. Processing and correction to at-surface data was completed by Karen Joyce (Joyce, 2004). Raw imagery consisted several images corresponding to the number of flight paths taken to cover the entire Heron Reef. Spatial resolution is one meter. Radiometric corrections converted the at-sensor digital number values to at surface spectral radiance values using sensor specific calibration coefficients and CSIRO's c-WomBat-c atmospheric correction software. Geometric corrections were done using field collected coordinates of features identified in the image. Projection used was Universal Transverse Mercator Zone 56 South and Datum used was WGS 84. Image data is in TIFF format.

Large size in an island-dwelling bird: intraspecific competition and the Dominance Hypothesis

Differences between island- and mainland-dwelling forms provide several classic ecological puzzles. Why, for instance, are island-dwelling passerine birds consistently larger than their mainland counterparts? We examine the 'Dominance hypothesis', based on intraspecific competition, which states that large size in island passerines evolves through selection for success in agonistic encounters. We use the Heron Island population of Capricorn silvereyes (Zosterops lateralis chlorocephalus), a large-bodied island-dwelling race of white-eye (Zosteropidae), to test three assumptions of this hypothesis; that (i) large size is positively associated with high fitness, (ii) large size is associated with dominance, and (iii) the relationship between size and dominance is particularly pronounced under extreme intraspecific competition. Our results supported the first two of these assumptions, but provided mixed evidence on the third. On balance, we suggest that the Dominance Hypothesis is a plausible mechanism for the evolution of large size of island passerines, but urge further empirical tests on the role of intraspecific competition on oceanic islands versus that on mainlands.

Dimethyl sulfide and other biogenic volatile organic compound emissions from branching coral and reef seawater: Potential sources of secondary aerosol over the Great Barrier Reef

Volatile organic compounds (VOCs) in the headspace of bubble chambers containing branches of live coral in filtered reef seawater were analysed using gas chromatography with mass spectrometry (GC-MS). When the coral released mucus it was a source of dimethyl sulfide (DMS) and isoprene; however, these VOCs were not emitted to the chamber headspace from mucus-free coral. This finding, which suggests that coral is an intermittent source of DMS and isoprene, was supported by the observation of occasional large pulses of atmospheric DMS (DMSa) over Heron Island reef on the southern Great Barrier Reef (GBR), Australia, in the austral winter. The highest DMSa pulse (320 ppt) was three orders of magnitude less than the DMS mixing ratio (460 ppb) measured in the headspace of a dynamically purged bubble chamber containing a mucus-coated branch of Acropora aspera indicating that coral reefs can be strong point sources of DMSa. Static headspace GC-MS analysis of coral fragments identified mainly DMS and seven other minor reduced sulfur compounds including dimethyl disulfide, methyl mercaptan, and carbon disulfide, while coral reef seawater was an indicated source of methylene chloride, acetone, and methyl ethyl ketone. The VOCs emitted by coral and reef seawater are capable of producing new atmospheric particles < 15 nm diameter as observed at Heron Island reef. DMS and isoprene are known to play a role in low-level cloud formation, so aerosol precursors such as these could influence regional climate through a sea surface temperature regulation mechanism hypothesized to operate over the GBR.

Seawater carbonate chemistry, calcification rate, oxygen production, maximum quantum yield, symbiont density, chlorophyll concentration and crystal width of Halimeda macroloba, Halimeda cylindracea and Marginopora vertebralis during experiments, 2011

The effects of elevated CO2 and temperature on photosynthesis and calcification in the calcifying algae Halimeda macroloba and Halimeda cylindracea and the symbiont-bearing benthic foraminifera Marginopora vertebralis were investigated through exposure to a combination of four temperatures (28°C, 30°C, 32°C, and 34°C) and four CO2 levels (39, 61, 101, and 203 Pa; pH 8.1, 7.9, 7.7, and 7.4, respectively). Elevated CO2 caused a profound decline in photosynthetic efficiency (FV : FM), calcification, and growth in all species. After five weeks at 34°C under all CO2 levels, all species died. Chlorophyll (Chl) a and b concentration in Halimeda spp. significantly decreased in 203 Pa, 32°C and 34°C treatments, but Chl a and Chl c2 concentration in M. vertebralis was not affected by temperature alone, with significant declines in the 61, 101, and 203 Pa treatments at 28°C. Significant decreases in FV : FM in all species were found after 5 weeks of exposure to elevated CO2 (203 Pa in all temperature treatments) and temperature (32°C and 34°C in all pH treatments). The rate of oxygen production declined at 61, 101, and 203 Pa in all temperature treatments for all species. The elevated CO2 and temperature treatments greatly reduced calcification (growth and crystal size) in M. vertebralis and, to a lesser extent, in Halimeda spp. These findings indicate that 32°C and 101 Pa CO2, are the upper limits for survival of these species on Heron Island reef, and we conclude that these species will be highly vulnerable to the predicted future climate change scenarios of elevated temperature and ocean acidification.

Permeable coral reef sediment dissolution driven by elevated pCO2 and pore water advection

Ocean acidification (OA) is expected to drive the transition of coral reef ecosystems from net calcium carbonate (CaCO3) precipitating to net dissolving within the next century. Although permeable sediments represent the largest reservoir of CaCO3 in coral reefs, the dissolution of shallow CaCO3 sands under future pCO2 levels has not been measured under natural conditions. In situ, advective chamber incubations under elevated pCO2 (~800 µatm) shifted the sediments from net precipitating to net dissolving. Pore water advection more than doubled dissolution rates (1.10 g CaCO3/m**2/day) when compared to diffusive conditions (0.42 g CaCO3/m**2 /day). Sediment dissolution could reduce net ecosystem calcification rates of the Heron Island lagoon by 8% within the next century, which is equivalent to a 25% reduction in the global average calcification rate of coral lagoons. The dissolution of CaCO3 sediments needs to be taken into account in order to address how OA will impact the net accretion of coral reefs under future predicted increases in CO2.

Effects of reduced and business-as-usual CO2 emission scenarios on the algal territories of the damselfish Pomacentrus wardi (Pomacentridae)

Turf algae are a very important component of coral reefs, featuring high growth and turnover rates, whilst covering large areas of substrate. As food for many organisms, turf algae have an important role in the ecosystem. Farming damselfish can modify the species composition and productivity of such algal assemblages, while defending them against intruders. Like all organisms however, turf algae and damselfishes have the potential to be affected by future changes in seawater (SW) temperature and pCO2. In this study, algal assemblages, in the presence and absence of farming Pomacentrus wardi were exposed to two combinations of SW temperature and pCO2 levels projected for the austral spring of 2100 (the B1 "reduced" and the A1FI "business-as-usual" CO2 emission scenarios) at Heron Island (GBR, Australia). These assemblages were dominated by the presence of red algae and non-epiphytic cyanobacteria, i.e. cyanobacteria that grow attached to the substrate rather than on filamentous algae. The endpoint algal composition was mostly controlled by the presence/absence of farming damselfish, despite a large variability found between the algal assemblages of individual fish. Different scenarios appeared to be responsible for a mild, species specific change in community composition, observable in some brown and green algae, but only in the absence of farming fish. Farming fish appeared unaffected by the conditions to which they were exposed. Algal biomass reductions were found under "reduced" CO2 emission, but not "business-as-usual" scenarios. This suggests that action taken to limit CO2 emissions may, if the majority of algae behave similarly across all seasons, reduce the potential for phase shifts that lead to algal dominated communities. At the same time the availability of food resources to damselfish and other herbivores would be smaller under "reduced" emission scenarios.

Cleaner shrimp do clean

Apart from cleaner fish, there are many reports on cleaning by shrimps, yet whether shrimps actually 'clean', i.e. eat parasites in the wild, has not been demonstrated. For the first time, we show that, conclusively, cleaner shrimp in the wild do clean. We found crustacean ectoparasites from the Family Gnathiidae and the Class Copepoda in the gut contents of wild cleaner shrimp, Urocaridella sp. and Periclimenes holthuisi. In addition, they ate parasitic monogenean flatworms, Benedenia sp., offered to them in the laboratory. Finally, P. holthuisi, significantly reduced monogenean, Benedenia sp., loads by 74.5% on captive surgeonfish Ctenochaetus striatus within 48 h. Such large reductions in parasite loads are likely to benefit individual fish. These results emphasise the need for more information on the ecological role of cleaner shrimp on coral reefs.

Reproductive and feeding ecology of parasitic gnathiid isopods of epaulette sharks (Hemiscyllium ocellatum) with consideration of their role in the transmission of a haemogregarine

Epaulette sharks Hemiscyllium ocellatum were surveyed on Heron Island, Great Barrier Reef, Australia for gnathiid isopods and protozoan (haemogregarine) parasites to determine the prevalence and intensity of infection and to investigate the potential role of gnathiids as vectors of these haemogregarines, the first such study carried out on elasmobranchs. Juvenile gnathiids were collected and quantified using a novel non-invasive and chemical-free technique and gnathiid squashes were examined for haemogregarine developmental stages. The feeding and reproductive ecology of the Gnathia spp. was investigated to better understand the relationship between gnathiids and haemogregarines. Gnathiids were found on all sharks and intensities ranged between two and 66. Only third-stage gnathiid juveniles were found, which fell into two size groups (A and B). These juveniles remained attached to H. ocellatum for up to 17 days, the longest period of attachment yet recorded for gnathiids. Group A female gnathiids produced broods of 45-187 (median = 120) first stage juveniles from between 54 and 82 days (median = 63 days) after detachment. First stage juveniles survived for an average of 15.8 +/- 0.1 (SEM) days without feeding. The prevalence (6.7%) and parasitaemia (usually

Cleaner fish become hosts: a novel form of parasite transmission

Adult bucephalid trematodes (Digenea) generally only occur in piscivorous fish. Within labrid fishes they are very rare, however, we have found them in labrid cleaner fish that feed on the ectoparasites of fish. We surveyed 969 labrid fishes from the tropical Pacific and found bucephalids only in cleaners (Lahroides dimidiatus, L. bicolor, and Bodianus axillaris) and none in piscivores. The prevalences of bucephalids in L. dimidiatus at Lizard Island, Heron Island, Orpheus Island (all on the Great Barrier Reef), New Caledonia, and Moorea (French Polynesia) were 51, 47, 67, 56, and 67%, respectively. All of the L. bicolor examined from Moorea were infected. Bucephalids were highly prevalent in all size classes of L. dimidiatus from Lizard Island. Bucephalids were found in a 1.6-cm long juvenile L. dimidiatus, in which, piscivory is highly unlikely. We examined the literature on the worldwide bucephalid fauna in labrids and all hosts were found to be cleaners (Symphodus tinca, S. mediterraneus, L. dimidiatus, L. bicolor, and Bodianus axillaris) except Notolabrus parilus, whose ecology is unknown. We suggest that cleaners eat bucephalid metacercariae directly from the exterior surface of client fish during cleaning interactions. This is the first evidence of digeneans in the diet of L. dimidiatus, and the first study to show this novel form of parasite transmission where infective stages are eaten as a result of cleaning behaviour. Cleaning-mediated parasite transmission may result in behavioural modification of second intermediate hosts because clients and parasites both benefit from transmission. If the infection is costly to cleaners and acquired during cheating behaviour, then this parasite might regulate mutualism. Alternatively, if infective stages are targeted, infection by these bucephalids may be a negative consequence of an honest foraging strategy.

Ptychogyliauchen, a new genus of Gyliauchenidae (Platyhelminthes: Digenea) from siganid fishes of the Indo-West Pacific

We propose a new genus of the Gyliauchenidae Fukui, 1929 ( Digenea), Ptychogyliauchen, gen. nov., for four new species that infect Indo-West Pacific siganid fishes. Ptychogyliauchen, gen. nov. is a morphologically distinctive genus, diagnosed principally by the presence of a highly convoluted oesophagus, which generally exceeds the total body length of the worm, and by the unusual folded structure of the ejaculatory duct. Ptychogyliauchen thetidis, sp. nov. is designated as the type species, and is described from the intestine of Siganus punctatus (Siganidae) from Heron Island, Great Barrier Reef, Queensland, Australia. Ptychogyliauchen himinglaeva, sp. nov. is described from the intestine of Siganus corallinus ( Siganidae) from Lizard Island, Great Barrier Reef, Queensland, Australia. Ptychogyliauchen leucothea, sp. nov. is described from the intestine of S. argenteus, and further recorded from S. fuscescens, off Ningaloo, Western Australia, Australia. Ptychogyliauchen thistilbardi, sp. nov. is described from the intestine of S. doliatus from Noumea, New Caledonia, and is also found in S. argenteus, S. canaliculatus, S. corallinus and S. spinus from Noumea, New Caledonia, and Moorea, Tahiti, French Pacific. Ptychogyliauchen thistilbardi, sp. nov. also occurs in the intestine of Chaetodon citrinellus (Chaetodontidae) from Moorea. A key to species is provided. All species have been described following morphological examination using light microscopy, and specimens of P. thetidis, sp. nov., P. leucothea, sp. nov. and P. thistilbardi, sp. nov. have been characterised using molecular methods. Sequences were obtained for a combination of nuclear ribosomal (28S (D1-D3) and ITS2) and mitochondrial (ND1) genes. A phylogenetic analysis of sequenced specimens of Ptychogyliauchen, gen. nov. was conducted using species of Petalocotyle Ozaki, 1934 for outgroup comparison. This analysis, based on alignments of the ITS2 and 28S (D1-D3) rDNA genes, supports monophyly of the geographically widespread P. thistilbardi, sp. nov., which is known from both siganid and chaetodontid hosts. We discuss the taxonomy of the genus and the host associations of each species and the group.