Percorrer por autor "Marquardt, Bailey"
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- Determining the diversity and relative abundance of coral taxa in wild spawning slicks for effective restorationPublication . Marquardt, Bailey; Elder, Holland; Yeoh, Yun Kit; Heyward, Andrew; Randall, Carly J.; Harrison, Peter L.; Logan, Murray; Howells, EmilyCoral reefs are increasingly threatened by climate change-induced stressors, including marine heatwaves, which can lead to coral mortality, reduced reproductive output, and compromised natural recovery. Successful coral reef recovery requires the settlement of coral larvae and recruitment in degraded areas, replenishing coral communities and promoting resilience. Some restoration strategies involve utilizing natural spawning slicks, composed of coral gametes and embryos, to produce larvae to reseed reefs. However, verifying the taxonomic composition of these slicks is challenging. Here, we tested the performance of two coral ITS primer sets, CoralITS2 and CoralITS2_acro, on mock communities to evaluate their ability to capture genera composition and relative abundances. Both primer sets demonstrated high accuracy (>97%) in detecting and quantifying coral taxa. Subsequently, these primers were applied to wild-collected spawning slicks from the Great Barrier Reef, revealing variation in scleractinian (reef-building) coral community composition among slicks. For the CoralITS2_acro assay, Acropora was consistently the most abundant resolved genus detected across wild slick sample sites, with the exception of samples from the Whitsundays region, where Platygyra was dominant. The CoralITS2 assay successfully differentiated reef-building (Scleractinian) corals from other co-occurring spawning taxa, such as soft corals, anemones, and sponges, and revealed that these other co-spawners dominated slicks at two sites. Our findings underscore the potential of eDNA-based monitoring as a scalable tool to confirm the presence and relative abundance of diverse coral assemblages in natural slicks, informing restoration efforts. By enabling the characterization and comparison of slick composition across large spatial and temporal scales, eDNA metabarcoding can support restoration practices that align with the ecological requirements of reef ecosystems, safeguarding biodiversity and promoting resilience against future disturbances.
- Reproductive phenology and sexual propagation of the pink sea fan Eunicella verrucosa (Pallas, 1766): implications for coral restorationPublication . Egger, Christina; Melo, Catarina; Marquardt, Bailey; Engelen, Aschwin; Melzer, Roland R.; Santos, Elsa; Fernandes, Margarida; Baylina, Núria; Serrao, Ester A.; Coelho, Márcio A. G.The widespread decline of coral-dominated ecosystems has highlighted the urgent need for active habitat restoration. Coral restoration using sexually produced individuals instead of clonal fragments is essential to reduce impacts on donor populations and promote genetic diversity, which is vital for adaptability to environmental changes. However, for most coral species critical knowledge of reproduction and larval ecology for ex situ sexual propagation is lacking. To address this gap, this study presents the first report of spawning of the octocoral Eunicella verrucosa in the North-East Atlantic and describes larval development and settlement. The annual reproductive timing in SouthWest Portugal was determined from samples collected as fisheries bycatch from the same habitat and monitored for comparison across distinct durations and conditions. The species exhibited split spawning (three major events approximately every two weeks) over about one month (mid-September–mid-October). Spawning patterns can suggest lunar periodicity but shifted between colonies kept in distinct conditions. Oocytes were positively buoyant and developed into swimming larvae after three days. Settlement trials using substrates such as natural rock, crustose coralline algae (CCA), and gorgonian skeleton, showed larvae started testing the substrates about two weeks after spawning, with settlement activity continuing over up to three months. Fully developed recruits were observed after one month, with sclerite production starting before tentacle development. The observation of new larval settlement up to three months indicates a prolonged competency period. This study provides crucial data for coral restoration efforts using ex-situ sexual propagation of a vulnerable species.