Suppressed coral settlement following mass bleaching in the southern Persian/Arabian Gulf

Coral reefs in the southern Persian/Arabian Gulf have become increasingly degraded in the past two decades, mainly due to recurrent mass coral bleaching events. The recovery of these reefs will be largely contingent upon the arrival and settlement of coral larvae and their post settlement growth and survival. Spatial and temporal patterns of coral settlement were quantified on 10 sites spanning \u3e350 km of the southern Gulf using settlement tiles for two years when consecutive bleaching events occurred. Coral settlement was highly seasonal, with peak settlement occurring in summer each year (\u3e95% of spat), with the remainder of settlement in autumn. Coral settlement was \u3e2-fold greater in the first year (928 spat) compared to the second year (397 spat) representing overall settlement densities of 95 m−2 yr−1 versus 40 m−2 yr−1. The dramatic declines in larval settlement between years suggests bleaching-related impacts on fecundity occurred during the gametogenic cycle late in the first year, as well as impaired survivorship of larvae and/or spat during the second year when severe bleaching coincided with the peak settlement period. Poritids and merulinids (‘others’) comprised 4% and 94% of the spat, respectively, while acroporids were virtually absent (1 recorded spat), suggesting the continued extirpation of this formerly dominant group and a continuing shift towards more stress-tolerant assemblages. Settlement rates in the southern Gulf are low in comparison to other marginal reef environments, and the bleaching-related suppression of settlement observed here suggests that larval supply is unlikely to be sufficient to support recovery of these increasingly degraded habitats. Given the increasing frequency of bleaching events in the southern Gulf the prognosis for the future of regional reefs is grim

The Infrared Imaging Spectrograph (IRIS) for TMT: the atmospheric dispersion corrector

We present a conceptual design for the atmospheric dispersion corrector (ADC) for TMT's Infrared Imaging Spectrograph (IRIS). The severe requirements of this ADC are reviewed, as are limitations to observing caused by uncorrectable atmospheric effects. The requirement of residual dispersion less than 1 milliarcsecond can be met with certain glass combinations. The design decisions are discussed and the performance of the design ADC is described. Alternative options and their performance tradeoffs are also presented.Comment: SPIE Astronomical Instrumentation 201

Does citation matter? Research citation in policy documents as an indicator of research impact – an Australian obesity policy case-study

Background: Citation of research in policy documents has been suggested as an indicator of the potential longer-term impacts of research. We investigated the use of research citations in childhood obesity prevention policy documents from New South Wales (NSW), Australia, considering the feasibility and value of using research citation as a proxy measure of research impact. Methods: We examined childhood obesity policy documents produced between 2000 and 2015, extracting childhood obesity-related references and coding these according to reference type, geographical origin and type of research. A content analysis of the policy documents examined where and how research was cited in the documents and the context of citation for individual research publications. Results: Over a quarter (28%) of the policy documents (n = 86) were not publicly available, almost two-thirds (63%) contained references, half (47%) cited obesity-related research and over a third (41%) of those containing references used unorthodox referencing styles, making reference extraction laborious. No patterns, in terms of the types of documents more likely to cite research, were observed and the number of obesity research publications cited per document was highly variable. In total, 263 peer-reviewed and 94 non-peer-reviewed obesity research publications were cited. Research was most commonly cited to support a policy argument or choice of solution. However, it was not always possible to determine how or why individual publications were cited or whether the cited research itself had influenced the policy process. Content analysis identified circumstances where research was mentioned or considered, but not directly cited. Conclusions: Citation of research in policy documents in this case did not always provide evidence that the cited research had influenced the policy process, only that it was accessible and relevant to the content of the policy document. Research citation across these public health policy documents varied greatly and is unlikely to be an accurate reflection of actual research use by the policy agencies involved. The links between citation and impact may be more easily drawn in specific policy areas or types of documents (e.g. clinical guidelines), where research appraisal feeds directly into policy recommendations

Temporal variation in macroalgal removal: insights from an impacted equatorial coral reef system

Macroalgal removal is a critical ecosystem function yet few studies have considered its temporal variability, especially on impacted reefs with limited herbivorous fish biodiversity. To address this, we quantified macroalgal removal and mass-standardised bite rates of herbivorous fishes monthly from July 2016 to June 2017 using a series of transplanted Sargassum ilicifolium assays and underwater video cameras on three degraded coral reefs in Singapore: Pulau Satumu, Kusu Island, and Terumbu Pempang Tengah. Our results revealed a distinct temporal pattern in macroalgal herbivory (proportion of biomass removed and mass-standardised bite rates) rates across all sites, increasing from July and decreasing from January, with the highest rates recorded in December (28.10 ± 3.05 g 3.5 h−1; 208.24 ± 29.99 mass-standardised bites 3.5 h−1) and the lowest in May (0.86 ± 0.17 g 3.5 h−1; 9.55 ± 3.19 mass-standardised bites 3.5 h−1). These coincided with the S. ilicifolium growth cycle, confirming previous evidence that herbivory rates are closely linked to macroalgal condition. Video analyses revealed nine species feeding over a year (31,839 bites; 8702.89 mass-standardised bites), with Siganus virgatus responsible for ∼ 80% of the total mass-standardised bites. Siganus virgatus took the largest proportion of bites monthly, except between April and June, when Scarus rivulatus was dominant, suggesting temporal constraints in functional roles

Selenoprotein W : Purification and characterization of its interaction with calmodulin

Selenoprotein W (SeW) is a protein whose function is unknown, but potentially plays a vital role in calcium metabolism, as an indirect link has been established with white muscle disease (WMD). White muscle disease occurs in selenium deficient animals, and is characterized by the precipitation of calcium in muscle, leading to paralysis and death. This thesis details efforts to purify and characterize SeW. This includes investigations into calcium binding, phosphorylation, and interaction with calmodulin (CaM). The main portion of the thesis consists of two manuscripts, the first dealing with the purification and production of SeW with and without bound glutathione, the second manuscript addresses SeW-CaM interaction. Supplemental material as well as the results of calcium binding studies and phosphorylation studies, are located in the appendices. Abstracts from the two manuscripts, follow. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) and electrospray ionization mass spectrometry (ESI MS) analysis of a 6x Histagged recombinant form of rat mutant selenoprotein W (RMSW) reveals that aerobic growth conditions primarily produce a form of RMSW without bound glutathione (10305 Da) whereas anaerobic conditions produce a glutathionebound (305 Da) form (10610 Da). Purification of RMSW was achieved with a procedure employing acetone precipitation and DEAE-cellulose chromatography, in addition to Ni-NTA agarose chromatography. Additional steps, including polyvalent metal ion binding (PMIB) resin chromatography and CM-cellulose chromatography, were necessary after elution from the Ni-NTA agarose column, in order to maintain solubility of the purified protein. Experiments applying partially purified extracts containing either rat mutant selenoprotein W (RMSW, Selenocysteine → cysteine, His₆ tag) or native rabbit selenoprotein W (SeW) to a calmodulin-sepharose column revealed that SeW interacts with calmodulin in a calcium dependent manner. Fluorescence polarization experiments with fluorescently labeled calmodulin and purified RMSW with and without bound glutathione revealed a Kd of 1.3 ± .1 X 10⁻⁶M for both forms of the protein. Competitive binding assays with myosin light chain kinase (MLCK) and fluorescently labeled calmodulin were performed for three peptide sequences (Nterm: GYKPKYLQLKEKL-NH2:, Rmid: VTVAGKLVHSKKRG-NH2, and Cterm: KFRKLVTAIKAALAQ-NH₂) which occur within proposed calmodulin binding sequences in rat SeW. The concentration of each peptide at which half-displacement of MLCK was achieved ([P]₅₀) was determined to be 5.5 nM, 6.3 nM, and 1.60 nM respectively. These values were used to estimate the dissociation constant of the peptide-calmodulin complex (Kr). The K values for Nterm and Rmid were determined to be < I nM, whereas the K for Cterm was determined to be 18 nM. In addition, during a preliminary test for specifity, a 100 fold excess of beef cardiac troponin C, a protein related to calmodulin, was unable to outcompete calmodulin for RMSW

Coral recruitment and early benthic community development on several materials used in the construction of artificial reefs and breakwaters

Artificial reefs are increasingly being promoted as a means to mitigate impacts from human activities in coastal urban areas. Coastal defense structures such as breakwaters are becoming recognized as large-scale artificial reefs that support abundant and diverse marine communities and play important roles in coastal ecology and management. However, there is limited understanding of how substrate materials used to construct artificial reefs or breakwaters can influence the development of habitat-forming benthic organisms. To assess the influence of substrata on coral recruitment and overall benthic community development, we deployed standard-size tiles of materials used in the construction of breakwaters and artificial reefs (concrete, gabbro, granite, and sandstone), along with terra-cotta for comparative purposes, at two breakwaters (DDD, PRT) and two natural reef sites (NR1, NR2) in Dubai, United Arab Emirates, for one year. Kruskal-Wallis ANOVA with post-hoc Mann-Whitney U-tests were used to examine differences in coral recruitment among sites and materials. Coral recruitment was highest at the DDD (4.9 ± 0.5 recruits 100 cm- 2), while recruitment was low and did not differ among other sites (PRT: 0.1 ± 0.04, NR1:0.3 ± 0.1, NR2: 0.1 ± 0.03 recruits 100 cm- 2). There were significant differences in coral recruitment among materials at DDD, where gabbro had higher recruit densities than concrete and sandstone; sandstone also contained less coral recruits than terra-cotta. Variability associated with low coral recruit densities precluded significant differences among materials at other sites. Overall benthic community structure differed more as a result of differences among sites than among substrate materials. Higher community dissimilarity was observed among sites than among material in SIMPER analysis, and significant differences were only observed among sites in ANOSIM. Univariate comparison of the benthos correlated with community differences in NMS ordination also showed significant differences among sites but not material. Overall, these results indicate that site-specific differences in recruitment patterns are more important in determining early benthic community structure and coral recruitment than are differences among substrate material. However, where coral recruitment is high, these results suggest that gabbro should be used preferentially over concrete or sandstone where it is feasible, but that granite may be a suitable alternative where it is the dominant stone. Coral recruitment on terra-cotta was comparable to all materials but sandstone, supporting its continued use in recruitment studies. These results also indicate that using stone amenable to coral recruitment is unlikely to influence the wider benthic community. © 2009 Elsevier B.V. All rights reserved

Macroalgal browsing on a heavily degraded, urbanized equatorial reef system

The removal of macroalgal biomass is critical to the health of coral reef ecosystems. Previous studies on relatively intact reefs with diverse and abundant fish communities have quantified rapid removal of macroalgae by herbivorous fishes, yet how these findings rel ate to degraded reef systems where fish diversity and abundance are markedly lower and algal biomass substantially higher, is unclear. We surveyed roving herbivorous fish communities and quantified their capacity to remove the dominant macroalga Sargassum ilicifolium on seven reefs in Singapore; a heavily degraded urbanized reef system. The diversity and abundance of herbivorous fishes was extremely low, with eight species and a mean abundance ~1.1 individuals 60 m -2 recorded across reefs. Consumption of S. ilicifolium varied with distance from Singapore's main port with consumption being 3- to 17-fold higher on reefs furthest from the port (Pulau Satumu: 4.18 g h -1 ; Kusu Island: 2.38 g h -1 ) than reefs closer to the port (0.35-0.78 g h -1 ). Video observations revealed a single species, Siganus virgatus, was almost solely responsible for removing S. ilicifolium biomass, accounting for 83% of the mass-standardized bites. Despite low herbivore diversity and intense urbanization, macroalgal removal by fishes on some Singaporean reefs was directly comparable to rates reported for other inshore Indo-Pacific reefs