Centre for Marine Studies Publications - UQ eSpace

A biochemical characterisation of the photophore lenses of Porichthys notatus Girard

Dove, S. og Horwitz, J. og McFall-Ngai, M. — 2010-02-17T11:36:13Z

A bloom of Lyngbya majuscula in Shoalwater Bay, Queensland, Australia: An important feeding ground for the green turtle (Chelonia mydas)

2007-08-15T00:00:00Z

Lyngbya majuscula, a toxic cyanobacterium, was observed blooming during June-July (winter) 2002 in Shoalwater Bay, Queensland, Australia, an important feeding area for a large population of green turtles (Chelonia mydas). The bloom was mapped and extensive mats of L majuscula were observed overgrowing seagrass beds along at least 18 km of coast, and covering a surface area of more than I I km(2). Higher than average rainfall preceded the bloom and high water temperatures in the preceding summer may have contributed to the bloom. In bloom samples, lyngbyatoxin A (LA) was found to be present in low concentration (26 mu g kg(-1) (dry weight)), but debromoaplysiatoxin (DAT) was not detected. The diet of 46 green turtles was assessed during the bloom and L. majuscula was found in 51% of the samples, however, overall it contributed only 2% of the animals' diets. L. majuscula contribution to turtle diet was found to increase as the availability of the cyanobacterium increased. The bloom appeared to have no immediate impact on turtle body condition, however, the presence of a greater proportion of damaged seagrass leaves in diet in conjunction with decreases in plasma concentrations of sodium and glucose could suggest that the turtles may have been exposed to a Substandard diet as a result of the bloom. This is the first confirmed report of L. majuscula blooming in winter in Shoalwater Bay, Queensland, Australia and demonstrates that turtles consume the toxic cyanobacterium in the wild, and that they are potentially exposed to tumour promoting compounds produced by this organism. (c) 2005 Elsevier B.V. All rights reserved.

A Call to Action for Coral Reefs

2009-04-14T00:00:00Z

A comparative ultrastructural study of spermatozoa of the teiid lizards Cnemidophorus gularis gularis, Cnemidophorus ocellifer, and Kentropyx altamazonica (Reptilia, Squamata, Teiidae)

2007-08-14T00:00:00Z

The ultrastructure of the spermatozoa of Cnemidophorus gularis gularis, Cnemidophorus ocellifer, and Kentropyx altamazonica is described for the first time. Mature spermatozoa of Cnemidophorus spp. and K. altamazonica differ in the occurrence of a perforatorial base plate, the enlargement of axonemal fibers 3 and 8, and shape of mitochondria. The comparisons of the ultrastructure sperm of Cnemidophorus spp. and K. altamazonica with Ameiva ameiva [J. Morphol. (2002) in press] suggest that Ameiva and Cnemidophorus are more similar to each other than either is to Kentropyx. Statistical analyses reveal that sperm of all three species studied are significantly different in the following dimensions: head, acrosome, distal centriole length, and nuclear shoulders width. There was no variable statistically different between the Cnemidophorus spp. only. The length of the tail, midpiece, entire sperm, and nuclear rostrum are significantly different between K. altamazonica and Cnemidophorus spp. Our results indicate that sperm ultrastructure presents intra and intergeneric variability. (C) 2002 Elsevier Science Ltd. All rights reserved.

A Conceptual Model of Impacts of Environmental Change on Human Well-Being

2004-09-17T00:00:00Z

Human well-being is dependent on goods and services provided by well-functioning ecosystems. Changes in ecosystem status and integrity can therefore impact directly and indirectly on human well-being. However, neither current measures of ecosystem health nor methods to value ecosystem services incorporate methods to assess impacts of changes in ecosystem health on human well-being. Assessment of these impacts is potentially useful in improving the sustainability of coastal management decision making. This paper presents a conceptual model developed to identify the potential links between ecosystem condition and human well-being. Based on existing literature, it is hypothesised that changes in coastal ecosystem condition may affect aspects of social and community relations through affecting people's sense of place, degree of involvement in the community and the extent to which they undertake recreation in the coastal environment. Changes in these aspects of social relations can have flow-on impacts on social capital, social networks, levels of trust and physical and mental health. Changes in ecosystem condition may also have more direct impacts on human health, through bacterial contamination of recreational waters, the presence of toxicants in seafood, or through the presence of toxic algal blooms in recreational waters. Regional economic production is also affected by changes in coastal ecosystems, through changes in the production of fishing, aquaculture and tourism industries. The conceptual model provides a basis for the development of a dynamic systems model to assess the impacts of changes in ecosystem health on human well-being. This information is necessary to ensure that decisions regarding the use of natural ecosystems are well-informed and therefore appropriate.

A conceptual model of impacts of environmental change on human well-being: Assessing the Social Economic impacts of change in coastal ecosystems

2007-08-24T00:00:00Z

A coral-specific primer for PCR amplification of the internal transcribed spacer region in ribosomal DNA

2007-08-13T00:00:00Z

Acquisition of symbiotic dinoflagellates (Symbiodinium) by juveniles of the coral Acropora longicyathus

2008-05-04T00:00:00Z

Scleractinian corals may acquire Symbiodinium from their parents (vertically) or from the environment (horizontally). In the present study, adult colonies of the coral Acropora longicyathus from One Tree Island (OTI) on the southern Great Barrier Reef (Australia) acquired two distinct varieties of symbiotic dinoflagellates (Symbiodinium) from the environment. Adult colonies had either Symbiodinium from clade C (86.7%) or clade A (5.3%), or a mixture of both clades A and C (8.0% of all colonies). In contrast, all 10-day-old juveniles were associated with Symbiodinium from clade A, while 83-day-old colonies contained clades A, C and D even though they were growing at the same location. Symbiodinium from clade A were dominant in both 10- and 83-day-old juveniles (99 and 97% of all recruits, respectively), while clade D was also found in 31% of 83-day-old juveniles. Experimental manipulation also revealed that parental association (with clade A or C), or the location within the OTI reef, did not influence which clade of symbiont was acquired by juvenile corals. The differences between the genetic identity of populations of Symbiodinium resident in juveniles and adult A. longicyathus suggest that ontogenetic changes in the symbiosis may occur during the development of scleractinian corals. Whether or not these changes are due to host selective processes or differences in the physical environment associated with juvenile versus adult colonies remains to be determined.

Acute tissue death (white syndrome) affects the microenvironment of tabular Acropora corals

2010-09-27T00:00:00Z

White syndrome (WS) is a collective term for coral diseases that cause acute tissue loss, resulting in apparently healthy tissue bordering on exposed skeleton. In this study, the microenvironmental condition and tissue structure of WS-affected tabular acroporid corals were assessed by O2 microelectrodes and histological techniques. The high spatial resolution of the microelectrode measurements enabled an evaluation of the extent of physiological changes at, and 2 cm away from, the WS border. Respiration of the coral host was decreased on the skeleton–tissue border but was comparable to that of healthy corals only 2 cm away from the border. Histological data, however, showed a decrease in mesogloea thickness on and 2 cm away from the WS border, which correlates with a previously observed allocation of photoassimilates away from the WS border. We suggest that there are colony-wide negative effects of WS which affect only the host physiology and, as disparate etiologies are evident in WS, these must be distinguished through the utilization of a multiple tool approach.

Adaptive management and its role in managing Great Barrier Reef water quality

2007-08-15T00:00:00Z

Adaptive management is the pathway to effective conservation, use and management of Australia’s coastal catchments and waterways. While the concepts of adaptive management are not new, applications involving both assessment and management responses are indeed limited at the national and regional scales. This paper outlines the components of a systematic framework for linking scientific knowledge, existing tools, planning approaches and participatory processes to achieve healthy regional partnerships between community, industry, government agencies and science providers to overcome institutional barriers and uncoordinated monitoring. The framework developed by the Coastal CRC (www.coastal.crc.org.au/amf/amf_index.htm) is hierarchical in the way it displays information to allow associated frameworks to be integrated, and represents a construct in which processes, information, decision tools and outcomes are brought together in a structured and transparent way for adaptive catchment and coastal management. This paper proposes how an adaptive management approach could be used to benefit the implementation of the Reef Water Quality Protection Plan (RWQPP).

Adaptive variation in coral geometry and the optimization of internal colony light climates

2007-09-19T00:00:00Z

1. The ability of photosynthetic organisms to adjust their light climate has high adaptive significance because irradiance can vary spatially by orders of magnitude. Using a plating (foliaceous) coral species (Turbinaria mesenterina), we tested the hypothesis that plasticity of colony geometry optimizes internal irradiance distributions. 2. We developed a two-dimensional model to predict the internal irradiance distribution of a foliaceous colony as a function of its geometry. Field tests showed that the model explained 85% of the variation in irradiance within colonies of T. mesenterina with minimal bias. 3. Colony plate angle, plate spacing and range of tissue distributions into the colony were exponential functions of water depth. In shallow water plates tended to be nearly vertical, narrowly spaced, and had living tissue only near the growing edge of the plate. In deep water plates grew more horizontally, were more widely spaced, and had living tissue extending well into the colony interior. This pattern of phenotypic plasticity effectively evens out differences in within-colony irradiances. 4. We compared within-colony irradiance distributions across light habitats (depth), based on the observed variation in colony geometry with water depth. Despite fourfold differences in environmental irradiance, within-colony irradiances had a common mode of 100-200 mu mol m(-2) s(-1). This is near the hypothesized photosynthetic optimum defined by the upper limit of the subsaturation parameter (E-k) of the photosynthesis-irradiance curve. 5. Our study demonstrates that phenotypic plasticity of colony geometry is an important mechanism for regulating light capture during growth in T. mesenterina, and facilitates near-optimal internal irradiances across a wide range of environmental light regimes.

A Decision Environment: Going Beyond a Decision Framework to Improve the Effectiveness of Decision Making in Natural Resource Management

2007-08-24T00:00:00Z

Advances and limitations of Individual-based models to analyze and predict dynamics of mangrove forests. A review

2008-07-14T00:00:00Z

Mangrove ecosystems are considered vulnerable to climate change as coastal development limits the ecosystem services and adaptations important to their survival. Although they appear rather simple in terms of species diversity, their ecology is complex due to interacting geophysical forces of tides, surface runoff, river and groundwater discharge, waves, and constituents of sediment, nutrients and saltwater. These interactions limit developing a comprehensive framework for science-based sustainable management practices. A suite of models have been developed independently by various academic and government institutions worldwide to understand the dynamics of mangrove ecosystems and to provide ecological forecasting capabilities under different management scenarios and natural disturbance regimes. The models have progressed from statistical tables representing growth and yield to more sophisticated models describing various system components and processes. Among these models are three individual-based models (IBMs) (FORMAN, KIWI, and MANGRO). A comparison of models’ designs reveal differences in the details of process description, particularly, regarding neighbor competition among trees. Each model has thus its speciﬁc range of applications. Whereas FORMAN and KIWI are most suitable to address mangrove forest dynamics of stands, MANGRO focuses on landscape dynamics on larger spatial scale. A comparison of the models and a comparison of the models with empirical knowledge further reveal the general needs for further ﬁeld and validation studies to advance our ecological understanding and management of mangrove wetlands.

Adverse feedback sequences in exploited marine systems: Are deliberate interruptive actions warranted?

Bakun, A. og Weeks, S. J. — 2007-08-15T00:00:00Z

Several mechanisms for self-enhancing feedback instabilities in marine ecosystems are identified and briefly elaborated. It appears that adverse phases of operation may be abruptly triggered by explosive breakouts in abundance of one or more previously suppressed populations. Moreover, an evident capacity of marine organisms to accomplish extensive geographic habitat expansions may expand and perpetuate a breakout event. This set of conceptual elements provides a framework for interpretation of a sequence of events that has occurred in the Northern Benguela Current Large Marine Ecosystem (off south-western Africa). This history can illustrate how multiple feedback loops might interact with one another in unanticipated and quite malignant ways, leading not only to collapse of customary resource stocks but also to degradation of the ecosystem to such an extent that disruption of customary goods and services may go beyond fisheries alone to adversely affect other major global ecosystem concerns (e.g. proliferations of jellyfish and other slimy, stingy, toxic and/or noxious organisms, perhaps even climate change itself, etc.). The wisdom of management interventions designed to interrupt an adverse mode of feedback operation is pondered. Research pathways are proposed that may lead to improved insights needed: (i) to avoid potential 'triggers' that might set adverse phases of feedback loop operation into motion; and (ii) to diagnose and properly evaluate plausible actions to reverse adverse phases of feedback operation that might already have been set in motion. These pathways include the drawing of inferences from available 'quasi-experiments' produced either by short-term climatic variation or inadvertently in the course of biased exploitation practices, and inter-regional applications of the comparative method of science.

Aerial exposure influences bleaching patterns

2007-08-15T00:00:00Z

Aerosol dispersal of the fish pathogen, Amyloodinium ocellatum

2007-08-15T00:00:00Z

Amyloodinium ocellatum, a frequently encountered parasite in marine aquaculture, was investigated to determine if infective dinospore stages could be transported in aerosol droplets. We used an in vivo model incorporating static and dynamic airflow systems and found dinospores of A. ocellatum could travel in aerosol droplets (up to 440 turn in a static system and up to 3 m in a dynamic one). This is the first record of this transmission pathway for a marine protozoan parasite. It is possible that other marine protozoans can transfer via the aerobiological pathway. Management of A. ocellatum infections in aquaculture facilities could be affected, particularly where tanks and ponds are situated in close proximity. (c) 2006 Elsevier B.V. All rights reserved.

A fossil reef from the last interglacial, Western Australia

2007-08-15T00:00:00Z

Age accuracy and resolution of Quaternary corals used as proxies for sea level

2008-02-18T00:00:00Z

The accuracy of global eustatic sea level curves measured from raised Quaternary reefs, using radiometric ages of corals at known heights, may be limited by time-averaging, which affects the variation in coral age at a given height. Time-averaging was assessed in uplifted Holocene reef sequences from the Huon Peninsula, Papua New Guinea, using radiocarbon dating of coral skeletons in both horizontal transects and vertical sequences. Calibrated 2 sigma age ranges varied from 800 to 1060 years along horizontal transects, but weighted mean ages calculated from 15-18 dates per horizon were accurate to a resolution within 154-214 yr. Approximately 40% of the variability in age estimate resulted from internal variability inherent to C-14 estimates, and 60% was due to time-averaging. The accuracy of age estimates of sea level change in studies using single dated corals as proxies for sea level is probably within 1000 yr of actual age, but can be resolved to <= 250 yr if supported by dates from analysis of a statistical population of corals at each stratigraphic interval. The range of time-averaging among reef corals was much less than that for shelly benthos. Ecological time-averaging dominated over sedimentological time averaging for reef corals, opposite to patterns reported from shelly benthos in siliciclastic environments. (c) 2006 Elsevier B.V. All rights reserved.

Aging Rhizophora seedlings from leaf scar nodes: A technique for studying recruitment and growth in mangrove forests

Duke, Norman C. og Pinzon, M. Zuleika S. — 2010-02-12T00:00:00Z

This paper proposes a rapid and non-destructive technique to age Rhizophora seedlings in the field, using the sequence of leaf nodes along main stems. Based on three- to four-year-old R. mangle seedlings planted in a bay on the Caribbean coast of Panama, it was found that rates of annual node production (=half of leaf production) in the terminal shoot was relatively constant between individuals in the same and similar sites, and for each individual when remeasured three or four times over 19 months. Marked differences, however, were scored between sites under obviously different light conditions, notably in shade (closed canopy) or sun (open canopy); estimates range from 3.8 (SE $\pm$ 0.3) to 7.0 (SE $\pm$ 0.6) nodes$\cdot$ shoot$^{-1} \cdot$ year$^{-1}$, respectively (note, these were comparable with branch shoots on mature trees nearby). Therefore, neighbouring seedlings in sites with the same light condition could be aged by dividing total counts of main stem nodes by the respective rate. But, of greater interest, seedlings in open sites were found to have annual peaks of internodal extension along their main stems. It followed that seedlings like these could be aged by counting the number of peaks. This provided a more robust means to age seedlings having unknown growth histories, since it did not assume constant annual node production. These characteristics of seedling growth offer a relatively simple means to age individuals, and to quickly characterize demographic patterns in seedling communities. The technique is limited by bark development obscuring nodes on lower stems, occurring after approximately six or more years in R. mangle. Furthermore, because node production was not apparently influenced by age, the technique may also apply to distal branches of larger trees in appropriate light conditions.

Agrobacterium rhizogenes-mediated transformation of medicinal plants from the family rhamnaceae

Rosic, Nedeljka — 2008-05-05T00:00:00Z

Original Research Paper: Ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) biosynthetic genes (ect ABC) derived from the halophilic bacterium Halomonas elongata were introduced into tomato (Lycopersicon esculentum) using an Agrobacterium-mediated gene-delivery system. Stable integration of the ectoine genes into the regenerated plant genomes was confirmed by PCR and Southern blot analyses. Expression of these genes was detected in the transgenic tomato plants by Northern blot analysis. The transgenic plants exhibited the normal growth characteristics of the non-transgenic plants. The concentration of ectoine increased with increasing salinity, and the increase was higher in the roots than in the leaves. The present data indicates that the turgor values of the ectoine transgenic tomato lines increased with increasing salt concentration. The data suggests that the accumulation of ectoine in transgenic tomato plants contributed to the maintenance of osmotic potential of the cells.

A late Miocene leaf assemblage from Coromandel Peninsula, New Zealand, and its climatic implications

Pole, Mike og Moore, Phillip R. — 2011-03-24T00:00:00Z

Algal assemblages in lagoonal reefs of Caribbean Oceanic Atolls

Diaz-Pulido, G. og Diaz, J. M. — 2010-07-13T00:00:00Z

Allozyme electrophoresis still represents a powerful technique in the management of coral reefs

Ridgway, T. — 2007-08-15T00:00:00Z

Understanding genetic variability and gene flow between populations of scleractinian corals separated by one to several hundred kilometers is crucially important as we head into a century of climate change in which an understanding of the connectivity of populations is a critically important question in management. Genetic methods that directly use molecular variance in the DNA should offer greater precision in detecting differences among individuals and populations than the more traditional allozyme electrophoresis. However, this paper highlights the point that the limited number of DNA markers that have been identified for scleractinian coral genetic studies do not necessarily offer greater precision than that offered by allozymes. In fact, at present allozyme electrophoresis yields greater information than the eight different DNA markers used in this study. Given the relative ease of use of allozymes and the wealth of comparable data sets from numerous previously published studies, allozyme electrophoresis should not be dismissed for population structure and connectivity studies on coral reefs. While continued effort should be placed into searching for new DNA markers, until a more sensitive DNA marker becomes available for scleractinian corals, allozyme electrophoresis remains a powerful and relevant technique for understanding the connectivity of coral population studies.

All-protein chromophores isolated from corals, quench superoxide radicals

2009-02-06T15:05:06Z

A low-latitude bloom of the surf-zone diatom, Anaulus australis (Centrales, Bacillariophyta) on the coast of Southern Queensland (Australia)

Hewson, I. og Oneil, J. M. og Abal, E. — 2007-08-14T00:00:00Z

A novel bloom of the surf diatom Anaulus australis Drebes et Schultz was observed in subtropical waters off Surfers' Paradise, Queensland, Australia (27 degrees 55'S; 153 degrees 23'E) in early May 2000. This is the lowest latitude in which an Anaulus australis surf diatom bloom has been reported. Nitrogen stable isotope analysis of surf diatoms may indicate anthropogenic nutrient inputs in this environment.

A mangrove hybrid, Sonneratia X gulngai (Sonneratiaceae) from north-eastern Australia

Duke, N. C. — 2010-07-09T00:00:00Z

A mangrove hybrid, sonneratia xurama (sonneratiaceae) from northern Australia and southern New Guinea

Duke, N. C. — 2010-07-20T00:00:00Z

The putative hybrid tree taxon, Sonneratia alba x 3. lanceolata, previously reported for two incomplete herbarium specimens from northern Australia and south-east West Irian, has since been observed and collected in mangrove forests of southern Papua New Guinea. It is morphologically uniform and is described as S. xurama. Notes on its floral phenology, distribution and ecology are given, including a key to all major Sonnevatia taxa in this region.

A method for extracting a high-quality RNA from Symbiodinium sp.

Rosic, N. N. og Hoegh-Guldberg, O — 2010-03-28T00:00:00Z

Good quality RNA is essential for a range of analyses including microarray and gene expression studies. A number of methods for RNA extraction from symbiotic dinoflagellates were assessed for their ability to recover a high-quality RNA applicable for evaluation of gene expression profiles. The recovery and quality of the obtained RNA were evaluated with respect to UV light absorbance profiles and automated microcapillary electrophoretic RNA separation. A modified RNA extraction procedure that combines two existing commercial kits, Trizol and Qiagen RNeasy kits, was efficiently employed for the recovery of a high-quality RNA under specific homogenization conditions. Cell homogenization using glass beads at the speed of 4,500 rpm for up to 6 min resulted in a good RNA recovery and preserved RNA integrity. A high-quality RNA obtained following the described procedure was successfully applied in reverse transcriptase-polymerase chain reaction (PCR) and in quantitative PCR studies. Gene expression profiles were changed with RNA extraction procedure, with the highest transcript numbers at precise conditions of cell homogenization. RNA samples with RNA integrity number values from 6 and above were recommended for downstream applications. This sequence of RNA isolation and RNA evaluation represents a methodological improvement required for functional genomic studies in dinoflagellates.

Amino acid availability determines the ratio of microcystin variants in the cyanobacterium planktothrix agardhii

2009-04-16T14:26:04Z

Amino acid residues in conodont elements

Kemp, A. R. — 2007-08-14T00:00:00Z

Thermally unaltered conodont elements, brachiopods. and vertebrates were analyzed with reverse phase high profile liquid chromatography to locate and quantify amino acid remnants of the original organic matrix in the fossils. No consistent similarities in amino acid content were found in conodont taxa. and criteria based on organic residues appear to have no taxonomic significance in the fossils tested from these localities. However, hydroxyproline. an amino acid that is found in the collagen molecules of animals. as well as in the glycoproteins in the cell walls and reproductive tissues of certain plants, is represented in most taxa. The organic matter retained in the impermeable crowns of conodont elements might have been derived originally from a form of collagen. Biochemical analyses. correlated with histochemical tests, demonstrate that organic matter is an integral part of the hyaline tissue of the element crown and not the result of surface contamination. Tests of a range of vertebrate and invertebrate fossil hard tissues produced similar results. The analyses indicate that hyaline tissue in the conodont element crown is not a form of vertebrate enamel. which contains no collagen. Albid tissue. with little or no organic content. is not a form of vertebrate bone or dentine, both based on collagen and low in mineral. Although these results do not help to determine the phylogenetic affinities of conodont animals, they indicate teat conodont elements do not contain hard tissues characteristic of vertebrate animals.

Amino acid substitutions around the chromophore of the chromoprotein Rtms5 influence polypeptide cleavage

2007-08-15T00:00:00Z

Extension of the conjugated pi-system of many all-protein chromophores with an acylimine bond is the basis for their red-shifted optical properties. The presence of this post-translational modification is evident in crystal structures of these proteins. Harsh denaturation of proteins containing an acylimine bond results in partial polypeptide cleavage. For the red fluorescent protein DsRed, the extent of cleavage is quantitative. However, this is not the case for the blue non-fluorescent chromoprotein Rtms5, even though all chromophores in tetrameric Rtms5 contain an acylimine bond. We have identified two positions around the chromophore of Rtms5 where substitutions can promote or suppress the extent of cleavage on harsh denaturation. We propose a model in which cleavage of Rtms5 is facilitated by a trans to cis isomerisation of the chromophore. (c) 2006 Elsevier Inc. All rights reserved.

Amino acid synthesis in the symbiotic sea anemone Aiptasia pulchella

Swanson, R. og Hoegh-Guldberg, O. — 2007-08-13T00:00:00Z

Symbiotic Aiptasia pulchella and freshly isolated zooxanthellae were incubated in (NaHCO3)-C-14 and NH4Cl for 1 to 240 min, and samples were analysed by reverse-phase high-performance liquid chromatography (HPLC) and an online radiochemical detector. NH4+ was first assimilated into C-14-glutamate and C-14-glutamine in the zooxanthellae residing in A. pulchella. The specific activities (dpm nmol(-1)) of C-14-glutamate and C-14-glutamine in vivo, were far greater in the zooxanthellae than in the host tissue, indicating that NH4+ was principally incorporated into the glutamate and glutamine pools of the zooxanthellae. C-14-alpha-ketoglutarate was taken up from the medium by intact A. pulchella and assimilated into a small amount of C-14-glutamate in the host tissue, but no C-14-glutamine was detected in the host fraction. The C-14-glutamate that was synthesized was most likely produced from transamination reactions as opposed to the direct assimilation of NH4+. The free aminoacid composition of the host tissue and zooxanthellae of A. pulchella was also measured. The results presented here demonstrate that NH4+ was initially assimilated by the zooxanthellae of A. pulchella.

Ampullary organ morphology of freshwater salmontail catfish Arius graeffei

2008-06-10T00:00:00Z

Analysis of an EST library from the dinoflagellate (Symbiodinium sp.) symbiont of reef-building corals

2008-05-04T00:00:00Z

Dinoflagellates (Symbiodinium sp. Freud.) are an obligatory endosymbiont of the reef-building corals. Recent changes to the environment surrounding coral reefs (e.g., global warming) have demonstrated that this endosymbiotic relationship between corals and Symbiodinium is particularly sensitive to environmental changes. Therefore, understanding gene expression patterns of Symbiodinium is critical to understanding why coral reefs are susceptible to global climate change. This study identified 1456 unique expression sequence tags (ESTs) generated for Symbiodinium (clade C3) from the staghorn coral Acropora aspera following exposure to a variety of stresses. Of these, only 10% matched previously reported dinoflagellate ESTs, suggesting that the conditions used in the construction of the library resulted in a novel transcriptome. The function of 561 (44%) of these ESTs could be identified. The majority of these genes coded for proteins involved in posttranslational modification, protein turnover, and chaperones (12.3%); energy production and conversion (12%); or an unknown function (18.6%). The most common transcript found was a homologue to a bacterial protein of unknown function. This algal protein is targeted to the chloroplast and is present in those phototrophs that acquired plastids from the red algal lineage. An additional 48 prokaryote-like proteins were also identified, including the first glycerol-phosphate:phosphate antiporter from dinoflagellates. A protein with similarity to the fungi-archael-bacterial heme catalase peroxidases was also found. A variety of stress genes, in particular heat-shock proteins and proteins involved in ubiquitin cascades, were also identified. This study is the first transcriptome from the unicellular component of a eukaryote-eukaryote symbiosis.

Analytical approach for selecting normalizing genes from a cDNA microarray platform to be used in q-RT-PCR assays: A cnidarian case study

2008-05-07T00:00:00Z

Research in gene function using Quantitative Reverse Transcription PCR (q-RT-PCR) and microarray approaches are emerging and just about to explode in the field of coral and cnidarian biology. These approaches are showing the great potential to significantly advance our understanding of how corals respond to abiotic and biotic stresses, and how host cnidarians/dinoflagellates symbioses are maintained and regulated. With these genomic advances, however, new analytical challenges are also emerging, such as the normalization of gene expression data derived from q-RTPCR. In this study, an effective analytical method is introduced to identify candidate housekeeping genes (HKG) from a sea anemone (Anthopleura elegantissima) cDNA microarray platform that can be used as internal control genes to normalize q-RT-PCR gene expression data. It is shown that the identified HKGs were stable among the experimental conditions tested in this study. The three most stables genes identified, in term of gene expression, were beta-actin, ribosomal protein L12, and a Poly(a) binding protein. The applications of these HKGs in other cnidarian systems are further discussed

An ancient and variable mannose-binding lectin from the coral Acropora millepora binds both pathogens and symbionts

2009-04-15T14:49:16Z

Corals form the framework of the world’s coral reefs and are under threat from increases in disease and bleaching (symbiotic dysfunction), yet the mechanisms of pathogen and symbiont recognition remain largely unknown. Here we describe the isolation and characterisation of an ancient mannose-binding lectin in the coral Acropora millepora, which is likely to be involved in both processes. The lectin (‘Millectin’) was isolated by affinity chromatography and was shown to bind to bacterial pathogens as well as coral symbionts, dinoflagellates of the genus Symbiodinium. cDNA analysis of Millectin indicate extensive sequence variation in the binding region, reflecting its ability to recognise various mannose-like carbohydrate structures on non-self cells, including symbionts and pathogens. This is the first mannose-binding lectin to show extensive sequence variability as observed for pattern recognition proteins in other invertebrate immune systems and, given that invertebrates rely on non-adaptive immunity, is a potential keystone component of coral defence mechanisms. Copyright 2008 Elsevier Ltd. All rights reserved.

An assessment of carbon dioxide gassing as a sampling technique for studies of the nexton of soft-sediment intertidal pools

Kwik, J. og Tibbetts, I. R. — 2008-06-10T00:00:00Z

Anatomy of a hemiramphid pharyngeal mill with reference to arrhamphus sclerolepis krefftii (steindachner) (teleostei: hemiramphidae)

Tibbetts, I. R. og Carseldine, L. — 2007-08-15T00:00:00Z

The structure and function of the pharyngeal jaw apparatus (PJA) and postpharyngeal alimentary tract of Arrhamphus sclerolepis krefftii, an herbivorous hemiramphid, were investigated by dissection, light and scanning electron microscopy, and X-ray analysis of live specimens. A simple model of PJA operation is proposed, consisting of an adductive power stroke of the third pharyngobranchial that draws it posteriorly while the fifth ceratobranchial is adducted, and a return stroke in which the third pharyngobranchial bone is drawn anteriorly during abduction of the fifth ceratobranchial. Teeth in the posteromedial region of the PJA are eroded into an occlusion zone where the teeth of the third pharyngobranchial are spatulate incisiform and face posteriorly in opposition to the rostrally oriented spatulate incisiform teeth in the wear zone of the fifth ceratobranchial. The shape of the teeth and their pedestals (bone of attachment) is consistent with the model and with the forces likely to operate on the elements of the PJA during mastication. The role of pharyngeal tooth replacement in maintaining the occlusal surfaces in the PJA during growth is described. The postpharyngeal alimentary tract of A. sclerolepis krefftii comprises a stomachless cylinder that attenuates gradually as it passes straight to the anus, interrupted only by a rectal valve. The ratio of gut length to standard length is about 0.5. Despite superficial similarities to the cichlid PJA (Stiassny and Jensen [1987] Bull Mus Comp Zool 151: 269-319), the hemiramphid PJA differs in the fusion of the third pharyngobranchial bones, teeth in the second pharyngobranchials and the fifth ceratobranchial face anteriorly, the presence of a slide-like diarthroses between the heads of the fourth epibranchials and the third pharyngobranchial, the occlusion zone of constantly wearing teeth, and the unusual form of the muscularis craniopharyngobranchialis. The functional relationship between these structures is explained and the consequence for the fish of a complex PJA and a simple gut is discussed. (C) 2002 Wiley-Liss, Inc.

Anatomy of the pharyngeal jaw apparatus of Zenarchopterus (Gill) (Teleostei : Beloniformes)

Tibbetts, I. R. og Carseldine, L. — 2007-08-15T00:00:00Z

The structure of the pharyngeal jaw apparatus (PJA) of Zenarchopterus dispar and Z. buffonis, carnivorous estuarine and freshwater West-Pacific halfbeaks, was investigated using dissection, light, and scanning electron microscopy as part of a comparison with estuarine and marine herbivorous confamilials. The Zenarchopterus PJA differs from published descriptions of hemiramphid PJAs in that the otic capsules are less pronounced; the pharyngocranial articulation facet is trough-like; the third pharyngobranchials are ankylosed; the second pharyngobranchial anterior processes are relatively hypotrophied; all pharyngeal teeth except the posterior teeth in the fifth ceratobranchial face posteriorly; the muscularis craniopharyngobranchialis 2 posterior is short; the muscularis craniopharyngobranchialis 2 anterior is lacking, as is its insertion site, the inferior parasphenoid apophysis; the protractor pectoralis is well developed; the pharyngocleithralis internus originates dorsal to the level of the fifth ceratobranchial bony process; the fifth ceratobranchial bony processes are directed ventrolaterally; the opposing upper and lower tooth fields appear not to occlude erosively; and the muscular portion of the pharyngohyoideus is well developed anteriorly. The extent of these differences and their implications for the function of the PJA support recent molecular studies that suggest that the Hemiramphidae is polyphyletic. (C) 2004 Wiley-Liss, Inc.

Ancient reefs

Pandolfi, John M. — 2009-03-20T00:00:00Z

An endemic mangrove species, Avicennia integra sp. nov. (Avicenniaceae), in northern Australia

Duke, N. C. — 2010-07-23T00:00:00Z

This taxon was recognised in Australian mangrove assemblages as Avicennia oficinalis L., which is commonly found in Indo-Malesia and southern New Guinea. However, it is morphologically distinct, and the major distinguishing character of entire margins for calyx and bracts is unique in the genus. This species, described here as A. integra, occurs only in the Northern Territory of Australia. It therefore has the dual distinction for an Australian mangrove species of not only being endemic, but also being absent from the floristically rich tidal forests of north-eastern Queensland. Notes on its floral phenology, distribution and ecology are also given.

An Entangled Two Photon Source using Biexciton Emission of an Asymmetric Quantum Dot in a Cavity

2004-02-04T00:00:00Z

A semiconductor based scheme has been proposed for generating entangled photon pairs from the radiative decay of an electrically-pumped biexciton in a quantum dot. Symmetric dots produce polarisation entanglement, but experimentally-realised asymmetric dots produce photons entangled in both polarisation and frequency. In this work, we investigate the possibility of erasing the `which-path' information contained in the frequencies of the photons produced by asymmetric quantum dots to recover polarisation-entangled photons. We consider a biexciton with non-degenerate intermediate excitonic states in a leaky optical cavity with pairs of degenerate cavity modes close to the non-degenerate exciton transition frequencies. An open quantum system approach is used to compute the polarisation entanglement of the two-photon state after it escapes from the cavity, measured by the visibility of two-photon interference fringes. We explicitly relate the two-photon visibility to the degree of Bell-inequality violation, deriving a threshold at which Bell-inequality violations will be observed. Our results show that an ideal cavity will produce maximally polarisation-entangled photon pairs, and even a non-ideal cavity will produce partially entangled photon pairs capable of violating a Bell-inequality.

An evolutionary hypothesis for the radiation of the Gyliauchenidae Goto & Matsudaira, 1918 (Platyhelminthes: Digenea)

2008-06-06T00:00:00Z

A new, extinct pleistocene reef coral from the Montastraea ‘‘Annularis’’ species complex

Pandolfi, John M. — 2008-02-18T00:00:00Z

A new species of the Montastraea "annularis" species complex is herein described from Pleistocene coral reefs of the Caribbean Sea. The species, Montastraea nancyi n. sp., had a broad geographic distribution at mainly insular sites 125 Ka. It has a fossil record extending from >600 Ka (thousand years) to 82 Ka, both first and last occurrences exclusively on the island of Barbados. It also had a broad environmental tolerance, occurring in fringing, windward back-reef and reef-crest, leeward reef-crest, and lagoonal patch-reef environments. In every habitat in which it lived, there are examples that it either dominated the coral fauna or shared dominance with Acropora palmata, a dominant shallow water coral in high-energy Pleistocene and modem reefs. The extinction of Montastraea nancyi resulted in evolutionary and ecological change in surviving members of the M. "annularis" species complex.

A new tetraphyllidean genus and species, Caulopatera pagei n. g., n. sp (Tetraphyllidea: Phyllobothriidae), from the grey carpetshark Chiloscyllium punctatum Muller & Henle (Orectolobiformes: Hemiscylliidae)

2010-08-29T00:00:00Z

A new genus and species of tetraphyllidean cestode, Caulopatera pagei n. g., n. sp., is described from the grey carpetshark Chiloscyllium punctatum Müller & Henle in Moreton Bay, Australia. The new genus is placed in the Phyllobothriidae, subfamily Phyllobothriinae. Caulopatera n. g. is distinct from all other phyllobothriine genera in having stalked, circular, non-loculate bothridia that lack an apical sucker, testes that are restricted to the region anterior to the cirrus-sac and circum-medullary vitelline follicles. The new genus most closely resembles Carpobothrium Shipley & Hornell, 1906, with which it shares non-loculate, stalked, unhooked bothridia without an accessory sucker and testes that are entirely anterior to the cirrus-sac, but differs from it in that it lacks a slit-like opening in each bothridium and flaps surrounding the opening. The possession of bothridial stalks is consistent with two cestode orders, the Tetraphyllidea and the Rhinebothriidea. The morphology of the bothridial stalks is consistent with other tetraphyllidean genera, in that Caulopatera possesses triangular bothridial stalks surrounding the back of the bothridia, indicating that it belongs in the Tetraphyllidea senso stricto, rather than in the recently recognised Rhinebothriidea. © 2010 Springer Science+Business Media B.V.

An integrated field and remote sensing approach for mapping seagrass cover, Moreton Bay, Australia

2009-09-03T00:00:00Z

An Introduction to the Great Barrier Reef

2009-04-15T00:00:00Z

An investigation of the chronological differences in the deposition of trace metals in the otoliths of two temperate reef fish

2010-02-11T15:55:28Z

Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) was used to determine broad scale chronological differences in the elemental composition of otoliths from two temperate reef fishes, Parma microlepis (Gunther) (Pomacentridae) and Achoerodus viridis (Steindachner) (Labridae). Estimates of a range of microconstituents (<10 μg ion per g of otolith) were obtained, including the low level constituents Ba, Co and Mn. The removal of otolith tissue by either acid digestion or diamond saw allowed the chemical composition of the centre (=early life of fish) and edge (=later life of fish) of otoliths to be accessed without detectable contamination. ICP-MS used with either of these methods can, therefore, access chronological information stored in the otoliths of fishes. Significant differences in elemental levels (e.g., Mn) were found between the otoliths of the two species of fishes and between study sites. For both Parma microlepis and Achoerodus viridis, the centre of the otolith contained less Ca than the edge. Chronological differences in trace metal composition were found when data were normalised to sample weight (e.g., Ba and Co in A. viridis), but these differences were not observed for data normalised to the Ca concentration of the otolith sample. The merits and problems associated with normalising ionic concentrations to weight, Ca concentration, or protein concentration are discussed with the conclusion that a greater understanding of the binding affinities of all the components of otoliths (organic, as well as inorganic matrices) is needed to be in a position to select either of these internal standards as appropriate for specific ions. Despite this, ICP-MS was found to be a powerful tool that can be used to determine microconstituent fingerprints in otoliths among locations and between comparable chronological sections (e.g., cores).

A novel carbonic anhydrase from the giant clam Tridacna gigas contains two carbonic anhydrase domains

2007-08-15T00:00:00Z

This report describes the presence of a unique dual domain carbonic anhydrase (CA) in the giant clam, Tridacna gigas. CA plays an important role in the movement of inorganic carbon (C-i) from the surrounding seawater to the symbiotic algae that are found within the clam's tissue. One of these isoforms is a glycoprotein which is significantly larger (70 kDa) than any previously reported from animals (generally between 28 and 52 kDa). This alpha-family CA contains two complete carbonic anhydrase domains within the one protein, accounting for its large size; dual domain CAs have previously only been reported from two algal species. The protein contains a leader sequence, an N-terminal CA domain and a C-terminal CA domain. The two CA domains have relatively little identity at the amino acid level (29%). The genomic sequence spans in excess of 17 kb and contains at least 12 introns and 13 exons. A number of these introns are in positions that are only found in the membrane attached/secreted CAs. This fact, along with phylogenetic analysis, suggests that this protein represents the second example of a membrane attached invertebrate CA and it contains a dual domain structure unique amongst all animal CAs characterized to date.

Antibody increases phagocytosis and killing of Lactococcus garvieae by rainbow trout (Oncorhynchus mykiss, L.) macrophages

2007-09-19T00:00:00Z

The present study reports that specific antibody increased the bactericidal activity of rainbow trout head-kidney macrophages against virulent capsulated Lactococcus garvieae in the absence of complement. The observed increased bactericidal activity appeared to result from increased phagocytosis of capsulated L. garvieae in the presence of specific antibody and may in part explain the protective effect of antibody previously reported against this disease. (C) 2002 Academic Press.