Exposure of benthic invertebrates to sediment vibration: From laboratory experiments to outdoor simulated pile-driving

Activities 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

Antibiotic resistance surveillance of Klebsiella pneumoniae complex is affected by refined MALDI-TOF identification, Swiss data, 2017 to 2022.

BackgroundModern laboratory methods such as next generation sequencing and MALDI-TOF allow identification of novel bacterial species. This can affect surveillance of infections and antimicrobial resistance. From 2017, increasing numbers of medical microbiology laboratories in Switzerland differentiated Klebsiella variicola from Klebsiella pneumoniae complex using updated MALDI-TOF databases, whereas many laboratories still report them as K. pneumoniae or K. pneumoniae complex.AimOur study explored whether separate reporting of K. variicola and the Klebsiella pneumoniae complex affected the ANRESIS surveillance database.MethodsWe analysed antibiotic susceptibility rates and specimen types of K. variicola and non-K. variicola-K. pneumoniae complex isolates reported by Swiss medical laboratories to the ANRESIS database (Swiss Centre for Antibiotic Resistance) from January 2017 to June 2022.ResultsAnalysis of Swiss antimicrobial resistance data revealed increased susceptibility rates of K. variicola compared with species of the K. pneumoniae complex other than K. variicola in all six antibiotic classes tested. This can lead to underestimated resistance rates of K. pneumoniae complex in laboratories that do not specifically identify K. variicola. Furthermore, K. variicola strains were significantly more often reported from blood and primarily sterile specimens than isolates of the K. pneumoniae complex other than K. variicola, indicating increased invasiveness of K. variicola.ConclusionOur data suggest that refined differentiation of the K. pneumoniae complex can improve our understanding of its taxonomy, susceptibility, epidemiology and clinical significance, thus providing more precise information to clinicians and epidemiologists

Exposure of benthic invertebrates to sediment vibration:From laboratory experiments to outdoor simulated pile-driving

Activities 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.</p

Increased noise levels have different impacts on the anti-predator behaviour of two sympatric fish species.

types: Journal ArticleCopyright: © 2014 Voellmy et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Animals must avoid predation to survive and reproduce, and there is increasing evidence that man-made (anthropogenic) factors can influence predator-prey relationships. Anthropogenic noise has been shown to have a variety of effects on many species, but work investigating the impact on anti-predator behaviour is rare. In this laboratory study, we examined how additional noise (playback of field recordings of a ship passing through a harbour), compared with control conditions (playback of recordings from the same harbours without ship noise), affected responses to a visual predatory stimulus. We compared the anti-predator behaviour of two sympatric fish species, the three-spined stickleback (Gasterosteus aculeatus) and the European minnow (Phoxinus phoxinus), which share similar feeding and predator ecologies, but differ in their body armour. Effects of additional-noise playbacks differed between species: sticklebacks responded significantly more quickly to the visual predatory stimulus during additional-noise playbacks than during control conditions, while minnows exhibited no significant change in their response latency. Our results suggest that elevated noise levels have the potential to affect anti-predator behaviour of different species in different ways. Future field-based experiments are needed to confirm whether this effect and the interspecific difference exist in relation to real-world noise sources, and to determine survival and population consequences.University of BristolBasler Stiftung für Biologische ForschungDefr

Mean fecal glucocorticoid metabolites are associated with vigilance, whereas immediate cortisol levels better reflect acute anti-predator responses in meerkats

Adrenal hormones likely affect anti-predator behavior in animals. With experimental field studies, we first investigated associations between mean fecal glucocorticoid metabolite (fGCs) excretion and vigilance and with behavioral responses to alarm call playbacks in free-ranging meerkats (Suricata suricatta). We then tested how vigilance and behavioral responses to alarm call playbacks were affected in individuals administered exogenous cortisol. We found a positive association between mean fGCs concentrations and vigilance behavior, but no relationship with the intensity of behavioral responses to alarm calls. However, in response to alarm call playbacks, individuals administered cortisol took slightly longer to resume foraging than control individuals treated with saline solution. Vigilance behavior, which occurs in the presence and absence of dangerous stimuli, serves to detect and avoid potential dangers, whereas responses to alarm calls serve to avoid immediate predation. Our data show that mean fGCs excretion in meerkats was associated with vigilance, as a re-occurring anti-predator behavior over long time periods, and experimentally induced elevations of plasma cortisol affected the response to immediate threats. Together, our results indicate an association between the two types of anti-predator behavior and glucocorticoids, but that the underlying mechanisms may differ. Our study emphasizes the need to consider appropriate measures of adrenal activity specific to different contexts when assessing links between stress physiology and different anti-predator behaviors

Overhead view of experimental tank setup.

<p>Schematic representation of visual predatory stimulus (PS), underwater loudspeaker (LS), focal fish position for predator release (X), feeder (F), artificial plant (P), mesh separator (S) and opaque Correx dividers (D).</p

Speed of response to a visual predatory stimulus.

<p>Minnows showed no significant effect of noise treatment on response latency (A), while sticklebacks responded significantly more quickly during additional-noise playbacks compared to control playbacks (B). Plots of Kaplan-Meier estimate from mixed model Cox proportional hazards regression, with non-responders included as right-censored maximum-latency data. N = two trials to each of 27 minnows and 35 sticklebacks.</p

Average spectral levels of acoustic conditions in the experimental tank.

<p>Sound pressure levels of averaged power spectra (FFT spectrum level units normalised to 1 Hz bandwidth, Hann window, FFT size 1024, 50% overlap) of recordings during band-pass filtered additional-noise playbacks (0.1 to 3.0 kHz; NT) and control playbacks (AT) at two tank depths (5 cm above tank floor and 5 cm below water surface) at the location the fish had to be for the visual predatory stimulus to be released. For control playbacks, spectral levels from 30 s recordings were assessed and averaged over all playback tracks and the two tank depths; for additional-noise playbacks, spectral levels over the whole duration of single looped elements were taken, to account for power fluctuations within a recording of sound emitted by a moving ship, and averaged over all playback tracks and the two tank depths. Recordings were made with an omni-directional hydrophone with preamplifier (HTI 96-MIN; manufacturer-calibrated sensitivity −164.3 dB re 1 µPa; frequency range 2–30 000 Hz) and a solid-state recorder (Edirol R09HR, Roland Corporation), at a sampling frequency of 44.1 kHz and a sampling rate of 16 bits; recording levels calibrated against a 1 kHz reference tone of known amplitude. An example of original ship-noise (NN) and ambient-noise recording (AN) of a UK harbour are given for comparison.</p