Reef Ecologic

Abstract The red seaweed Asparagopsis taxiformis can reduce methane emissions in livestock by over 90%, but its mariculture remains in its infancy and biomass for research and commercial use relies partly on wild populations. Knowledge on the impacts of harvesting A. taxiformis is lacking, emphasising the need for ecological research to guide the development of its sustainable harvesting. This study examined the regrowth potential of A. taxiformis meadows following small-scale harvesting. A harvest experiment testing the methods, handpicking and cutting, was conducted in Gladstone, Queensland, Australia, during the austral winter, with plots monitored over six months. Harvesting immediately affected percent cover and shoot length. Handpicked and cut plots exhibited regrowth within four to five months in terms of cover, which notably exceeded or were slightly above that of control plots. The shoot length of harvested plots paralleled that of control plots and was mainly influenced by seasonality. Control plots exhibited reduced growth at three months, suggesting that harvesting mimicked the seasonal reduction in biomass after the winter peak. This study also demonstrated the importance of vegetative propagation in the regrowth of A. taxiformis . The sessile benthic community in harvested plots underwent temporal shifts similar to those in the control plots, indicating that harvesting did not substantially alter community dynamics. Approximately 19 taxa of mobile fauna were recorded within Asparagopsis meadows, potentially indicating its habitat role. Overall, these findings provide ecological insights into the harvesting impacts on this seaweed, with further studies needed to assess broad-scale and long-term impacts.

Ocean warming threatens the persistence of tropical corals and the biologically diverse ecosystems they sustain. While field-based studies on heat impact have predominantly focused on quantifying coral bleaching, a symptom of thermal stress, less attention has been given to understanding trends in coral mortality, a critical metric for assessing and predicting the long-term effects of rising temperatures. Consequently, the relationships between varying heat exposures and resultant coral cover changes remain poorly quantified. Such trends are challenging to establish in the Tropical and Subtropical Western Atlantic (TWA), because climate change impacts are compounded by local anthropogenic and natural disturbances. Additionally, many coral communities have already been substantially altered, with those remaining dominated by relatively resilient species. This study addresses this issue by quantifying coral cover loss as a function of maximum Degree Heating Weeks (DHW) exposure using observed in-situ coral cover changes across reefs in the TWA. Of the five locations assessed (the Florida Keys, Dry Tortugas, Puerto Rico, the US Virgin Islands, and the East and West Flower Garden Banks), all exhibited significant declines in mean coral cover with increasing DHW exposure. Rates ranged from 0.3% to 2.4% annual loss in relative mean cover per unit DHW, with spatial variability largely reflecting pre-impact system conditions and variations in the life-history traits of geographically distinct coral assemblages (e.g., Puerto Rico vs East and West Flower Garden Banks). Variation in responses to DHW among species was also observed across locations. By establishing site-specific coral loss parameters, this study contributes to our understanding of how future coral cover may evolve under escalating thermal stress in the TWA. It also provides practical guidance for targeted restoration by identifying species that have fared comparatively well across locations, grounding efforts in what is possible under current and future conditions rather than idealised historical baselines.

In this paper, we present a pragmatic, step-by-step solution to the anomalous galaxy rotation curve problem. We begin by comparing modern and ancient measuring techniques, which revealed an inverse relationship requiring a Doppler velocity correction factor of (-1), subsequently we found by vector analysis that instant orbital velocity when observed from outside the orbit appears faster by a factor of \( \sqrt{2} \) , and last but not least we found it necessary to make a relativistic correction, gamma \( \gamma = \frac{1}{\sqrt{2GM/rc^2}} \) to the luminous mass. These three corrections predicted galaxy rotation curves with excellent accuracy. Doppler data and luminous mass profiles from 5 well studied galaxies were analysed and found to be in excellent agreement. Moreover we found that it was possible using the inverse formula \( M_{r} = v^2 r / 2G \) to calculate the exact luminous mass profile from Doppler velocity data.

ABSTRACT Urbanisation has profound effects on environmental water fluxes and storages, which can be further compounded by climate change and management responses. This study shows how climate change influences the type and amount of recharge in urban areas with different housing densities under Perth, Western Australia. We demonstrate that consequent water conservation measures aimed to reduce irrigation may be having unintended negative consequences by increasing urban heating. Groundwater recharge was measured under Perth, Western Australia, in 1980–81 and again in 2017–18, a 38-year climate period which saw annual rainfall fall by 150 mm; months with heavy rain reduce by half; maximum annual temperatures increase by more than 1°C and potential evaporation increase by 15%. The consequent reduction in direct recharge through soils due to climate change was enhanced by regulated reductions in sprinkler irrigation, whilst interception losses via tree canopies increased as rain fell as lighter showers rather than prolonged events. Indirect recharge off roofs and roads, however, was less affected and now dominates recharge to the shallow, unconfined aquifer. The primary management response to falling groundwater levels has been to reduce extraction from the aquifer. We propose an additional viable strategy would be managed aquifer recharge, using either water from main drains that remove groundwater, or secondary-treated wastewater, which is currently pumped to the ocean. Increasing, or at least maintaining, local irrigation could provide multiple positive benefits, including evaporative cooling over large urban areas to help reverse urban heating. Increased urbanisation worldwide generally increases urban runoff and generates urban heat islands. In cities, such as Perth, built over transmissive sand aquifers, however, increasing local recharge can provide valuable non-potable water and help urban cooling. Identifying and installing additional recharge systems, however, is difficult for managers as it requires innovation and additional resourcing compared with purely restricting licensed extraction.

This paper presents laboratory and field test results on the use of tire cell track foundation (TCTF) consisting of an assembly of infilled rubber tires to reinforce capping material below the ballast layer. Large-scale cubical triaxial tests were carried out with two different infill materials (crushed basalt rockfill and recycled spent ballast) and they were subjected to varying cyclic loading magnitudes and frequencies. A multistage cyclic loading was performed with and without the inclusion of tire cell reinforcement, whereby the cyclic loading was applied in four different stages with 25,000 loading cycles in each stage. In the first two stages, the frequency was increased from 10 to 15 Hz for an equivalent axle load of 25 t. For the third stage, the axle loading was increased to 35 t with a frequency of 10 Hz, which was then increased to 15 Hz in the final stage. The results showed that the TCTF could reduce the vertical stress transmitted to the subgrade layer as well as curtail the vertical and lateral displacement of the ballast layer. The TCTF further stabilized the track without any significant reduction of the resilient modulus of the overlying ballast as the loading and frequency increased. Compared to a traditional track, the TCTF showed a reduction of 40.1% and 28.3% in the breakage index for the crushed latite basalt and spent ballast (i.e., recycled from ballast tips) infilling the tire cells, respectively. Test results confirm that the TCTF can significantly improve the overall track performance, and this could be mainly attributed to the increased confining pressure provided by the tire cell assembly, as well as the enhanced damping properties of the rubber tire inclusions. In addition, the concept of TCTF was tested using a fully instrumented track (20 m long) subjected to the passage of a 22-t locomotive with two fully loaded carriages. The trial section was constructed within a maintenance yard for heavy haul rolling stock located in a western suburb of Sydney, Australia. Field measurements revealed that, compared to the standard track, the TCTF significantly reduces stress transfer to the subgrade soil. This ultimately mitigates excessive deformation and subgrade failure, making TCTF a sustainable solution for soft and weak subgrade soils despite initial settlement.

Chickens in Australia have recently been identified with symptoms and morphological findings including spondylitis attributed to pathogenic Enterococcus cecorum. Notably, there is limited information on clinical E. cecorum strains in Australia. The cpsO gene, located downstream of the capsular polysaccharide (cps) locus, was recently reported to successfully differentiate between pathogenic and commensal E. cecorum strains, as this gene is highly conserved in the pathogenic strains. In this study, pathogenic E. cecorum, with a conserved cpsO gene, was detected on 1 of the 2 farms studied in Australia. E. cecorum strains isolated from clinical sites of the diseased birds from the second farm did not have the cpsO gene and were distant from the isolates of the first farm. A cpsO PCR of the caecal content of the birds on this farm was positive, while cpsO PCR of washed culture plates where the tissue extracts were spread onto and incubated for bacterial growth was negative. This suggests that pathogenic E. cecorum with the cpsO gene, as detected in Farm 1 and reported in other countries, was present in the second farm but could not grow on the selective agar plates during the initial step of E. cecorum isolation. Nevertheless, E. cecorum isolated from the clinical sites on the second farm might represent the pathogenic strain, but further animal studies are required to validate this possibility. Phylogenetic analysis showed that the pathogenic strains in Australia were most closely related to the clinical strains in North America.

Exposure to more frequent ocean warming events is driving the loss of coral reef cover as the window of recovery between episodes of bleaching reduces. Coral propagation via in situ nurseries and subsequent outplanting have increased worldwide to support replenishing coral cover on degraded reefs. However, challenges in identifying fast-growing and bleaching-resistant target corals have limited how informative we can be regarding the resilience of outplanted corals. Here, we employed short-term thermal stress assays using the Coral Bleaching Automated Stress System (CBASS) to assess the thermal threshold of a fast-growing coral pre- and post-propagation on in situ nursery frames. We show that year-long nursery-propagated corals exhibit a statistically significant reduction in thermal thresholds (i.e., ED50s) compared to their corresponding reef-based donor colonies based on dose–response modelling of dark acclimated photosynthetic efficiency. RNA-Seq was then used to assess the underlying drivers of this thermotolerance reduction, identifying that processes involved in metabolic and oxidative stress management were disrupted in nursery versus donor heat-treated corals. Whether trade-offs during potential growth-focused phases (post-fragmentation), nursery conditions, and/or a consecutively high summer heat-load drove the lower thermal capacity remains to be determined. However, nursery corals expressed genes associated with telomere maintenance, which are typically expressed in stress-sensitive fast-growing corals under seasonal environmental stress, suggesting consecutively high summer heat-loading contributed to the observed patterns. Our results highlight that thermal tolerance is (i) variable and (ii) subject to acclimation to varying degrees across colonies. Thus, a path forward for reef practitioners to improve propagation efforts may entail the initial screening of a larger reef population from which thermally superior colonies can be selected for propagation.

If you can find a project or a way to reach your target audience on a large scale, then you've hit the jackpot. The Museum of Underwater Art installed on the Great Barrier Reef in 2017 contains the largest underwater sculpture in the world. It is an innovative project with a focus on people, planet and profit that has a huge wow factor and has reached previously unthinkable, massive global audiences of over 184 million people through the unique combination of world class art, community science and coral reefs. The biomorphic Ocean Sentinel sculptures of scientists and conservationists make locals proud, and tourists go to learn, be inspired, and take action to protect the Great Barrier Reef. Here we show that scientists communicate with relatively small numbers of (generally) scientists. However, the Museum of Underwater Art allows a collaboration between art and science to amplify the audience reach by up to 6,500 times. A future challenge is to contextualize the current global coral bleaching and build on communication to leverage behaviour change for climate action.