Biology subjects

Vermeulen, E.

Publications and source records attributed to Vermeulen, E..

3 recordsLinked to original sources

bioRxiv2025

Impact of flushing procedures on drinking water biostability and invasion susceptibility in distribution systems

Maintaining microbial stability in drinking water distribution systems (DWDS) is a priority for water providers, yet operational events like flushing and the potential invasion of unwanted microorganisms pose significant challenges. This study utilized a pilot-scale DWDS to evaluate the susceptibility of drinking water networks after standard operational flushing procedures (with and without chlorination) as these procedures can alter biostability. Results showed that flushing with chlorination reduced bulk cell counts initially but led to subsequent microbial regrowth, highlighting the limitations of chlorination in long-term biostability. Biofilm cell densities and community composition were similar before and after flushing with and without chlorination. Additionally, the susceptibility of a flushed network against introduced bacterial indicators (Aeromonas media, Pseudomonas putida, and Serratia fonticola) was investigated. The invasion experiments revealed that the species decayed more rapidly in loops flushed with chlorination. This study emphasizes the trade-off between potential regrowth and microbial control, underscoring the need for strategies that enhance microbial resilience without fostering regrowth. These findings are critical for optimizing DWDS management practices to ensure drinking water safety and quality. ImportanceFlushing, with or without chlorination, is a standard procedure used by drinking water providers to address water quality issues such as brown water, as well as following waterworks, or contaminant detection. This process involves discharging large volumes of drinking water, often through fire hydrants. Depending on the contamination, additional disinfectants, such as free chlorine, are dosed during flushing. However, the longer-term effects of these processes on microbial dynamics are unknown. For example, while brown water issues can be solved, the overall biostability of drinking water may be compromised, potentially making the drinking water distribution systems more susceptible to the invasion of unwanted microorganisms. Studying these practices in full-scale distribution networks is challenging. Therefore, in this study, a unique drinking water distribution pilot system that mimics a real network with mature biofilm was used to investigate the changes in both bulk water and biofilm microbiomes following flushing procedures.

microbiology↗

bioRxiv2023

Universal baleen whale microsatellite panel for individual identification and power to detect parentage

Highly polymorphic single tandem repeat loci (STR, also known as microsatellite loci) remain a familiar, cost efficient class of markers for genetic analyses in ecology, behavior and conservation. We characterize a new universal set of ten STR loci (from 28 potential candidate loci) in seven baleen whale species, which are optimized for PCR amplification in two multiplex reactions along with a Y chromosome marker for sex determination. The optimized, universal set of STR loci provides an ideal starting point for new studies in baleen whales aimed at individual-based and population genetic studies, and facilitates data sharing among research groups. Data from the new STR loci were combined with genotypes from other published STR loci to assess the power to assign parentage (paternity) using exclusion in four species: fin whales, humpback whales, blue whales and bowhead whales. We argue that parentage studies should present a power analysis to demonstrate that the specific data are sufficiently informative to assign parentage with statistical rigor.

genetics↗

bioRxiv2022

Wildlife and Marine Mammal Spatial Observatory: Observation and automated detection of Southern Right Whales in multispectral satellite imagery

The Wildlife and Marine Mammal Spatial Observatory is a joint research effort for the census of wildlife and particularly of marine mammals in satellite imagery. In that context, this paper illustrates the development of a high accuracy algorithm for the detection of right whales in sub-meter resolution multispectral satellite imagery with the constraint of a relatively small sample support of 580 southern right whale images. A significant space is devoted to exploratory data analysis to describe the statistical structure of right whale pixels and ocean surface pixels across multispectral bands. Observations of southern right whale in satellite imagery are divided into typical and atypical right whale forms and the first observations of right whale mother and calf pairs in satellite imagery are presented. Measurements of whales are furthermore automatically extracted from whale observations (major axis length, minor axis length, etc). A significant space is also devoted to statistical data exploration, a step frequently overlooked in machine learning solutions, that yet offers interesting insight into the structure of animal detection in satellite imagery. The extracted statistics can readily be used by researchers to develop detection solutions even with low sample support. The adopted solution for detection consists of feature extraction with a convolutional neural network followed by classification with a support vector machine. 20 different convolutional neural networks were tested for feature extraction. Biostatistics parameters (accuracy, sensitivity, specificity and precision) were measured for comparison. Most architectures generally achieved high performance with low false positive and false negative rates. 100% accuracy is achieved in the case of 2 convolutional neural networks, Nasnet Large and Inception V3, and only with a specific selection of multispectral bands. NB: This is a preprint that does not include satellite imagery due recent reviews

bioinformatics↗