Cintia Oliveira Carvalho

• Mahlangu, Sibusiso; Ewers, Isabelle; Carvalho, Cintia Oliveira; Schrøder-Nielsen, Audun; Dunthorn, Micah & Karlsen, Hans Erik [Show all 12 contributors for this article] (2025). Investigating the dynamics of the aquatic community in Oslofjord through time series analysis of eDNA. Journal of Fish Biology. ISSN 0022-1112. doi: 10.1111/jfb.70105. Full text in Research Archive Show summary

  Understanding the temporal dynamics of marine communities is critical for assessing ecosystem health and guiding conservation efforts. Here, we conducted a survey using environmental DNA (eDNA) metabarcoding with two primer sets, MiFish and Elas02, to investigate seasonal and interannual changes in the fish community of Oslofjord (Norway) over two consecutive years. Using the MitoFish reference database through the Global Biodiversity Information Facility querying tool, we identified 63 fish species and found significant changes in the dominant taxa between seasons and years. Clupea harengus (Atlantic herring) consistently peaked in early spring, while Scomber scombrus (Atlantic mackerel) dominated winter months in the second year. The MiFish primer set showed increased species richness in the second year, whereas the Elas02 primer set showed stable richness despite compositional turnover. Non-metric multidimensional scaling revealed distinct community separation between years in presence/absence of data, driven by species turnover rather than abundance read changes. Our findings support the use of eDNA metabarcoding to capture fine-scale (bi-monthly) temporal dynamics and emphasise the importance of multi-year datasets for distinguishing ecological trends from stochastic changes. This strategy improves monitoring practices for marine ecosystems under anthropogenic stressors.

• Carvalho, Cintia Oliveira; Gromstad, William Esbjug; Dunthorn, Micah; Karlsen, Hans Erik; Schrøder-Nielsen, Audun & Ready, Jonathan Stuart [Show all 10 contributors for this article] (2024). Harnessing eDNA metabarcoding to investigate fish community composition and its seasonal changes in the Oslo fjord. Scientific Reports. 14(1). doi: 10.1038/s41598-024-60762-8. Full text in Research Archive Show summary

  In the face of global ecosystem changes driven by anthropogenic activities, effective biomonitoring strategies are crucial for mitigating impacts on vulnerable aquatic habitats. Time series analysis underscores a great significance in understanding the dynamic nature of marine ecosystems, especially amidst climate change disrupting established seasonal patterns. Focusing on Norway's Oslo fjord, our research utilises eDNA-based monitoring for temporal analysis of aquatic biodiversity during a one year period, with bi-monthly sampling along a transect. To increase the robustness of the study, a taxonomic assignment comparing BLAST+ and SINTAX approaches was done. Utilising MiFish and Elas02 primer sets, our study detected 63 unique fish species, including several commercially important species. Our findings reveal a substantial increase in read abundance during specific migratory cycles, highlighting the efficacy of eDNA metabarcoding for fish composition characterization. Seasonal dynamics for certain species exhibit clear patterns, emphasising the method's utility in unravelling ecological complexities. eDNA metabarcoding emerges as a cost-effective tool with considerable potential for fish community monitoring for conservation purposes in dynamic marine environments like the Oslo fjord, contributing valuable insights for informed management strategies.

• Carvalho, Cintia Oliveira; Pazirgiannidi, Melina; Ravelomanana, Tsilavina; Andriambelomanana, Fetra; Schrøder-Nielsen, Audun & Ready, Jonathan Stuart [Show all 9 contributors for this article] (2024). Multi-method survey rediscovers critically endangered species and strengthens Madagascar's freshwater fish conservation. Scientific Reports. 14(1). doi: 10.1038/s41598-024-71398-z. Full text in Research Archive Show summary

  Freshwater ecosystems are crucial for global biodiversity through supporting plant and animal species and providing essential resources. These ecosystems are under significant threat, particularly in island environments such as Madagascar. Our study focuses on the Amboaboa River basin, home to the rare and endemic fish species Rheocles derhami, last recorded in 2013. To assess the status of this and other threatened fish species including Ptychochromis insolitus and Paretroplus gymnopreopercularis, and to understand freshwater fish population dynamics in this biodiversity hotspot, we conducted a comprehensive survey using both environmental DNA (eDNA) and traditional fishing methods. While traditional methods effectively captured a diverse range of species, including several invasive aliens and the critically endangered endemic species that were the focus of this study, the eDNA approach detected only a fraction of these introduced species and struggled to identify some critically endangered endemics at the species level. This highlights the value of combining methods to enhance species detection. We also investigated the trade-offs associated with multi-primer assessments in eDNA analysis, focusing on three different primer combinations targeting the 12S mitochondrial gene: MiFish, Tele02, and Riaz. Additionally, we provided 12S reference barcodes for 10 species across 9 genera of fishes from the region to increase the coverage of the public reference databases. Overall, our study elucidates the current state of freshwater biodiversity in the Amboaboa River basin and underscores the value of employing multiple methods for effective conservation strategies.

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• Mahlangu, Sibusiso; Ewers, Isabelle; Carvalho, Cintia Oliveira; Schrøder-Nielsen, Audun; Dunthorn, Micah & Karlsen, Hans Erik [Show all 12 contributors for this article] (2025). Investigating the dynamics of the aquatic community in Oslofjord through time series analysis of eDNA. BioRxiv. ISSN 0362-4331. doi: 10.1101/2025.02.05.636659. Full text in Research Archive

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