Biology subjects

Christoforou, E.

Publications and source records attributed to Christoforou, E..

3 recordsLinked to original sources

bioRxiv2024

Enhancing metabarcoding efficiency and ecological insights through integrated taxonomy and DNA reference barcoding: a case study on beach meiofauna

Molecular techniques like metabarcoding, while promising for exploring diversity of communities, are often impeded by the lack of reference DNA sequences available for taxonomic annotation. Our study explores the benefits of combining targeted DNA barcoding and morphological taxonomy to improve metabarcoding efficiency, using beach meiofauna as a case study. Beaches are globally important ecosystems and are inhabited by meiofauna, microscopic animals living in the interstitial space between the sand grains, which play a key role in coastal biodiversity and ecosystem dynamics. However, research on meiofauna faces challenges due to limited taxonomic expertise and sparse sampling. We generated 775 new cytochrome c oxidase I DNA barcodes from meiofauna specimens collected along the Netherlands west coast and combined them with the NCBI GenBank database. We analysed alpha and beta diversity in 561 metabarcoding samples from 24 North Sea beaches, a region extensively studied for meiofauna, using both the enriched reference database and the NCBI database without the additional reference barcodes. Our results show a 2.5-fold increase in sequence annotation and a doubling of species-level Operational Taxonomic Units (OTUs) identification when annotating the metabarcoding data with the enhanced database. Additionally, our analyses revealed a bell-shaped curve of OTU richness across the intertidal zone, aligning more closely with morphological analysis patterns, and more defined community dissimilarity patterns between supralittoral and intertidal sites. Our research highlights the importance of expanding molecular reference databases and combining morphological taxonomy with molecular techniques for biodiversity assessments, ultimately improving our understanding of coastal ecosystems.

molecular biology↗

bioRxiv2023

The effects of artificial light at night (ALAN) on the gaping activity and feeding of mussels

Artificial light at night (ALAN) is one of the most widespread forms of environmental pollution. Studies on terrestrial organisms have shown that the effects of ALAN can be pervasive, and importantly, can depend on the colour (i.e., wavelength) of light. ALAN also affects marine environments as it is present in more than 22% of the worlds coastlines and can reach depths of up to 100m. However, the impact of different colour ALAN on coastal marine organisms is under-investigated. In this study, we tested the effects of different ALAN colours on Mytilus edulis, a widespread coastal bivalve known for its high phytoplankton clearance capacity amongst other valuable ecosystem services. Using a lab-based valvometry system, we recorded the impact of red, green, and white ALAN on gaping activity patterns and phytoplankton clearance capacity of individual mussels and compared these to dark night control. Mussels exhibited a semi-diel activity pattern in both proportion of time open and gaping frequency. Although ALAN did not have significant effects on the proportion of time open it did significantly affect the gaping frequency. This effect was colour-specific with red and white ALAN resulting in lower activity compared to the dark night control but there were no effects on the phytoplankton consumption. Under green light, however, mussels showed a higher gaping frequency and reduced phytoplankton consumption with increasing time spent open compared to the other ALAN treatments and the dark control. Our findings suggest that ALAN does have colour-specific effects on mussels and indicate the importance of further investigating the physiological mechanisms behind these patterns, and their potential ecological consequences.

ecology↗

bioRxiv2021

Wavelength-dependent effects of artificial light at night on phytoplankton growth and community structure

Artificial light at night (ALAN) is increasingly recognised as a disruptive form of environmental pollution, impacting many physiological and behavioural processes that may scale up to population and community-level effects. Mounting evidence from animal studies show that the severity and type of the impact depends on the wavelength and intensity of ALAN. This knowledge has been instrumental for informing policy-making and planning for wildlife-friendly illumination. However, most of this evidence comes from terrestrial habitats, while research testing alternative wavelength illumination in marine environments is lagging behind. In this study we investigated the effect of such alternative ALAN colours on marine primary producers. Specifically, we tested the effect of green, red, and natural white LED illumination at night, compared to a dark control, on the growth of a green microalgae as well as the biomass, diversity and composition of a phytoplankton assemblage. Our findings show that green ALAN boosted chlorophyll production at the exponential growth stage, resulting in higher biomass production in the green algae Tetraselmis suesica. All ALAN wavelengths affected the biomass and diversity of the assemblage with the red and green ALAN having the stronger effects, leading to higher overall abundance and selective dominance of specific diatom species compared to white ALAN and the dark control. SynthesisOur work indicates that the wavelength of artificial light sources in marine areas should be carefully considered in management and conservation plans. In particular, green and red light should be used with caution in coastal areas, where there might be a need to strike a balance between the strong effects of green and red light on marine primary producers with the benefit they bring to other organisms.

ecology↗