574 research outputs found
Boat noise impacts risk assessment in a coral reef fish but effects depend on engine type.
This is the author accepted manuscript. The final version is available from Nature Publishing Group via the DOI in this record.Human noise pollution has increased markedly since the start of industrialization and there is international concern about how this may impact wildlife. Here we determined whether real motorboat noise affected the behavior, space use and escape response of a juvenile damselfish (Pomacentrus wardi) in the wild, and explored whether fish respond effectively to chemical and visual threats in the presence of two common types of motorboat noise. Noise from 30 hp 2-stroke outboard motors reduced boldness and activity of fish on habitat patches compared to ambient reef-sound controls. Fish also no longer responded to alarm odours with an antipredator response, instead increasing activity and space use, and fewer fish responded appropriately to a looming threat. In contrast, while there was a minor influence of noise from a 30 hp 4-stroke outboard on space use, there was no influence on their ability to respond to alarm odours, and no impact on their escape response. Evidence suggests that anthropogenic noise impacts the way juvenile fish assess risk, which will reduce individual fitness and survival, however, not all engine types cause major effects. This finding may give managers options by which they can reduce the impact of motorboat noise on inshore fish communities.We would like to thank the staff at Lizard Island for logistical support and Georgina Torras Jorda for spending
many hours driving small boats around. Funding was provided by an Australian Research Council Centre
of Excellence for Coral Reef Studies (EI140100117) and the Natural Environment Research Council (NE/
P001572/1)
Impacts of climate change on the body size of horse mackerel in the North Sea
Clear biogeographic trends persist in the body sizes of individuals in marine communities, with smaller species and individuals within species found in warmer waters. Based on this trend (Bergmann’s Rule), communities undergoing warming at a given location are likely to become more representative of body sizes seen in warmer waters. Using fisheries independent North Sea survey data with established catchability corrections, we investigated the effect of 30 years of warming on average size and species size distributions. We found, as an example, that horse mackerel (Trachurus trachurus) is consistent with Bergmann’s Rule, with larger average sizes seen at higher latitudes. Over 30 years a significant decline in average size has occurred at several latitudes. Using a Eulerian (grid based) approach and dividing the North Sea into 82 1° x 1° cells, 56% of cells displayed size distributions shifting towards populations with higher proportions of smaller individuals. Changing size distribution correlated significantly with warming over the study period. Horse mackerel’s northern range is in the northern North Sea, indicating populations at species range boundaries may be most affected by further warming. This finding warrants further work on a wider number of species. Changing body sizes and shifts in size distributions has implications for ecosystem functioning, trophic level dynamics and the value of fisheries
Fish in habitats with higher motorboat disturbance show reduced sensitivity to motorboat noise
This is the author accepted manuscript. The final version is available from the Royal Society via the DOI in this recordAnthropogenic noise can negatively impact many taxa worldwide. It is possible that in noisy, high
disturbance environments the range and severity of impacts could diminish over time, but the
influence of previous disturbance remains untested in natural conditions. This study demonstrates
effects of motorboat noise on the physiology of an endemic cichlid fish in Lake Malaŵi. Exposure to
motorboats (driven 20–100 m from fish) and loudspeaker-playback of motorboat noise both
elevated oxygen-consumption rate at a single lower-disturbance site, characterised by low historic
and current motorboat activity. Repeating this assay at further lower-disturbance sites revealed a
consistent effect of elevated oxygen consumption in response to motorboat disturbance. However,
when similar trials were repeated at four higher-disturbance sites, no effect of motorboat exposure
was detected. These results demonstrate that disturbance history can affect local population
responses to noise. Action regarding noise pollution should consider the past, as well as the present,
when planning for the future.NERC–Marine Scotland Science CASE GW4+ Studentship (H.R.H.; NE/L002434/1); NERC
Grant (S.D.S & A.N.R; NE/P001572/1)
The impact of experimental impact pile driving on oxygen uptake in black seabream and plaice
This is the final version of the article. Available from Acoustical Society of America via the DOI in this record.Fourth International Conference on the Effects of Noise on Aquatic Life, Dublin, Ireland, 10-16 July 2016Anthropogenic noise is a recognized global pollutant that could potentially impact many organisms, including fishes. One of the acoustic sources producing high impulsive noise and vibration is pile driving. However, the potential impacts of real pile driving on fish species has received little attention, mainly due to the logistical challenges involved. Here, we investigated the impact of pile driving on the oxygen uptake (a secondary stress response) of black seabream Spondyliosoma cantharus and European plaice Pleuronectes platessa using an experimental pile driver setup in a flooded ship-building dock. Each individual fish was tested in ambient and pile driving conditions using a counterbalanced paired design to control for potential order effects. During pile driving, black seabream increased oxygen uptake compared to the ambient control condition suggesting higher stress levels. Plaice did not show differences in oxygen consumption between the pile driving and ambient treatment. These results show the impact of pile driving on secondary stress responses in fish, highlight species-specific differences concerning acoustical impacts, and showcase the possibility of carrying out large-scale semi-field acoustic experiments.Thanks also to E.ON, NERC MREKE and Marine Scotland for financial support
Exposure of benthic invertebrates to sediment vibration: From laboratory experiments to outdoor simulated pile-driving
This is the final version of the article. Available from Acoustical Society of America via the DOI in this record.Fourth International Conference on the Effects of Noise on Aquatic Life, Dublin, Ireland, 10-16 July 2016Activities directly interacting with the seabed, such as pile-driving, can produce vibrations that have the potential to impact benthic invertebrates within their vicinity. This stimuli may interfere with crucial behaviors such as foraging and predator avoidance, and the sensitivity to vibration is largely unknown. Here, the responsiveness of benthic invertebrates to sediment vibration is discussed in relation to laboratory and semi-field trials with two marine species: the mussel (Mytilus edulis) and hermit crab (Pagurus bernhardus). Sensory threshold curves were produced for both species in controlled laboratory conditions, followed by small-scale pile-driving exposures in the field. The merits of behavioral indicators are discussed, in addition to using physiological measures, as a method of determining reception and measuring responses. The measurement and sensors required for sediment vibration quantification are also discussed. Response and threshold data were related to measurements taken in the vicinity of anthropogenic sources, allowing a link between responsiveness and actual operations. The impact of pile-driving on sediment-dwelling invertebrates has received relatively little research, yet the data here suggest that such activities are likely to impact key coastal species which play important roles within the marine environment.LR would like to thank the organizers and sponsors of the 2016 conference for
supporting her attendance for which she is extremely grateful. This study was partially
funded by a research award from the Malacological Society of London to LR. The
authors would also like to acknowledge Defra and NERC who funded the laboratory and
field work aspects respectively, and the staff at the OREC field site, Blyth
Mismatched single stranded antisense oligonucleotides can induce efficient dystrophin splice switching
<p>Abstract</p> <p>Background</p> <p>Antisense oligomer induced exon skipping aims to reduce the severity of Duchenne muscular dystrophy by redirecting splicing during pre-RNA processing such that the causative mutation is by-passed and a shorter but partially functional Becker muscular dystrophy-like dystrophin isoform is produced. Normal exons are generally targeted to restore the dystrophin reading frame however, an appreciable subset of dystrophin mutations are intra-exonic and therefore have the potential to compromise oligomer efficiency, necessitating personalised oligomer design for some patients. Although antisense oligomers are easily personalised, it remains unclear whether all patient polymorphisms within antisense oligomer target sequences will require the costly process of producing and validating patient specific compounds.</p> <p>Methods</p> <p>Here we report preclinical testing of a panel of splice switching antisense oligomers, designed to excise exon 25 from the dystrophin transcript, in normal and dystrophic patient cells. These patient cells harbour a single base insertion in exon 25 that lies within the target sequence of an oligomer shown to be effective at removing exon 25.</p> <p>Results</p> <p>It was anticipated that such a mutation would compromise oligomer binding and efficiency. However, we show that, despite the mismatch an oligomer, designed and optimised to excise exon 25 from the normal dystrophin mRNA, removes the mutated exon 25 more efficiently than the mutation-specific oligomer.</p> <p>Conclusion</p> <p>This raises the possibility that mismatched AOs could still be therapeutically applicable in some cases, negating the necessity to produce patient-specific compounds.</p
Angiotensin-converting enzyme genotype and late respiratory complications of mustard gas exposure
<p>Abstract</p> <p>Background</p> <p>Exposure to mustard gas frequently results in long-term respiratory complications. However the factors which drive the development and progression of these complications remain unclear. The Renin Angiotensin System (RAS) has been implicated in lung inflammatory and fibrotic responses. Genetic variation within the gene coding for the Angiotensin Converting Enzyme (ACE), specifically the Insertion/Deletion polymorphism (I/D), is associated with variable levels of ACE and with the severity of several acute and chronic respiratory diseases. We hypothesized that the ACE genotype might influence the severity of late respiratory complications of mustard gas exposure.</p> <p>Methods</p> <p>208 Kurdish patients who had suffered high exposure to mustard gas, as defined by cutaneous lesions at initial assessment, in Sardasht, Iran on June 29 1987, underwent clinical examination, spirometric evaluation and ACE Insertion/Deletion genotyping in September 2005.</p> <p>Results</p> <p>ACE genotype was determined in 207 subjects. As a continuous variable, FEV<sub>1 </sub>% predicted tended to be higher in association with the D allele 68.03 ± 20.5%, 69.4 ± 21.4% and 74.8 ± 20.1% for II, ID and DD genotypes respectively. Median FEV<sub>1 </sub>% predicted was 73 and this was taken as a cut off between groups defined as having better or worse lung function. The ACE DD genotype was overrepresented in the better spirometry group (Chi<sup>2 </sup>4.9 p = 0.03). Increasing age at the time of exposure was associated with reduced FEV<sub>1 </sub>%predicted (p = 0.001), whereas gender was not (p = 0.43).</p> <p>Conclusion</p> <p>The ACE D allele is associated with higher FEV<sub>1 </sub>% predicted when assessed 18 years after high exposure to mustard gas.</p
Enhancing automated analysis of marine soundscapes using ecoacoustic indices and machine learning
This is the final version. Available on open access from Elsevier via the DOI in this record. Historically, ecological monitoring of marine habitats has primarily relied on labour-intensive, non-automated
survey methods. The field of passive acoustic monitoring (PAM) has demonstrated the potential of this practice to
automate surveying in marine habitats. This has primarily been through the use of ‘ecoacoustic indices’ to
quantify attributes from natural soundscapes. However, investigations using individual indices have had mixed
success. Using PAM recordings collected at one of the world’s largest coral reef restoration programmes, we
instead apply a machine-learning approach across a suite of ecoacoustic indices to improve predictive power of
ecosystem health. Healthy and degraded reef sites were identified through live coral cover surveys, with 90–95%
and 0–20% cover respectively. A library of one-minute recordings were extracted from each. Twelve ecoacoustic
indices were calculated for each recording, in up to three different frequency bandwidths (low: 0.05–0.8 kHz,
medium: 2–7 kHz and broad: 0.05–20 kHz). Twelve of these 33 index-frequency combinations differed significantly between healthy and degraded habitats. However, the best performing single index could only correctly
classify 47% of recordings, requiring extensive sampling from each site to be useful. We therefore trained a
regularised discriminant analysis machine-learning algorithm to discriminate between healthy and degraded
sites using an optimised combination of ecoacoustic indices. This multi-index approach discriminated between
these two habitat classes with improved accuracy compared to any single index in isolation. The pooled classification rate of 1000 cross-validated iterations of the model had a 91.7% 0.8, mean SE) success rate at correctly
classifying individual recordings. The model was subsequently used to classify recordings from two actively
restored sites, established >24 months prior to recordings, with coral cover values of 79.1% (±3.9) and 66.5%
(±3.8). Of these recordings, 37/38 and 33/39 received a classification as healthy respectively. The model was
also used to classify recordings from a newly restored site established <12 months prior with a coral cover of
25.6% (±2.6), from which 27/33 recordings were classified as degraded. This investigation highlights the value
of combining PAM recordings with machine-learning analysis for ecological monitoring and demonstrates the
potential of PAM to monitor reef recovery over time, reducing the reliance on labour-intensive in-water surveys
by experts. As access to PAM recorders continues to rapidly advance, effective automated analysis will be needed
to keep pace with these expanding acoustic datasets.Natural Environment Research CouncilSwiss National Science FoundationNatural Environment Research Council (NERC)University of ExeterMars Sustainable Solution
The sound of recovery: coral reef restoration success is detectable in the soundscape (article)
This is the final version. Available on open access from Wiley via the DOI in this recordThe dataset associated with this article is available in ORE at https://doi.org/10.24378/exe.37031. Pantropical degradation of coral reefs is prompting considerable investment in their active restoration. However, current measures of restoration success are based largely on coral cover, which does not fully reflect ecosystem function or reef health. 2. Soundscapes are an important aspect of reef health; loud and diverse soundscapes guide the recruitment of reef organisms, but this process is compromised when degradation denudes soundscapes. As such, acoustic recovery is a functionally important component of ecosystem recovery. 3. Here, we use acoustic recordings taken at one of the world’s largest coral reef restoration projects to test whether successful restoration of benthic and fish communities is accompanied by a restored soundscape. We analyse recordings taken simultaneously on healthy, degraded (extensive historic blast fishing) and restored reefs (restoration carried out for 1–3 years on previously-degraded reefs). We compare soundscapes using manual counts of biotic sounds (phonic richness), and two commonly used computational analyses (acoustic complexity index [ACI] and sound-pressure level [SPL]). 4. Healthy and restored reef soundscapes exhibited a similar diversity of biotic sounds (phonic richness), which was significantly higher than degraded reef soundscapes. This pattern was replicated in some automated analyses but not others; the ACI exhibited the same qualitative result as phonic richness in a low-frequency, but not a high-frequency bandwidth, and there was no significant difference between SPL values in either frequency bandwidth. Further, the low-frequency ACI and phonic richness scores were only weakly correlated despite showing a qualitatively equivalent overall result, suggesting that these metrics are likely to be driven by different aspects of the reef soundscape. 5. Synthesis and applications: These data show that coral restoration can lead to soundscape recovery, demonstrating the return of an important ecosystem function. They also suggest that passive acoustic monitoring (PAM) might provide functionally important measures of ecosystemlevel recovery – but only some PAM metrics reflect ecological status, and those that did are likely to be driven by different communities of soniferous animals. Recording soundscapes represents a potentially valuable tool for evaluating restoration success across ecosystems, but caution must be exercised when choosing metrics and interpreting results.Natural Environment Research Council (NERC)Swiss National Science FoundationUniversity of ExeterMARS Sustainable Solution
GLAST: Understanding the High Energy Gamma-Ray Sky
We discuss the ability of the GLAST Large Area Telescope (LAT) to identify,
resolve, and study the high energy gamma-ray sky. Compared to previous
instruments the telescope will have greatly improved sensitivity and ability to
localize gamma-ray point sources. The ability to resolve the location and
identity of EGRET unidentified sources is described. We summarize the current
knowledge of the high energy gamma-ray sky and discuss the astrophysics of
known and some prospective classes of gamma-ray emitters. In addition, we also
describe the potential of GLAST to resolve old puzzles and to discover new
classes of sources.Comment: To appear in Cosmic Gamma Ray Sources, Kluwer ASSL Series, Edited by
K.S. Cheng and G.E. Romer
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