Percorrer por autor "Becker, Lina"
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- Mesozooplankton community dynamics in response to suppressed upwelling: a case study comparing the gulf of panama and the Gulf of Chiriquí using automated image analysisPublication . Becker, Lina; Mendes, Isabel Maria de Paiva Pinto; Schiebel, RalfThis thesis investigates mesozooplankton community dynamics in response to anomalous oceanographic conditions, focusing on the 2025 collapse of the seasonal upwelling in the Gulf of Panama. Using a comparative approach with the neighboring Gulf of Chiriquí, the study integrates semi-automated FlowCam imaging with supervised machine learning classifiers to process over 750,000 plankton images. This methodology enabled reliable abundance, and biomass estimates for dominant taxa, particularly copepods, at resolutions and scales unattainable through traditional microscopy. Hydrographic measurements revealed strongly stratified conditions in the Gulf of Panama, with suppressed nutrient input into the euphotic zone. In contrast, the Gulf of Chiriquí maintained relatively stable conditions. Ecological consequences were profound: the Gulf of Panama, typically characterized by high productivity due to upwelling, exhibited markedly reduced mesozooplankton abundance and biomass. Conversely, the Gulf of Chiriquí showed unexpectedly higher biomass across most depths, highlighting its role as a potential analogue for future oligotrophic states under climate-driven variability. Copepods remained the numerically and functionally dominant group, underscoring their resilience and central role in trophic transfer. However, size-structured analyses revealed that biomass patterns were not solely linked to abundance but strongly influenced by ontogenetic stage distribution. The disproportionate contribution of larger size fractions to carbon stocks emphasizes the importance of monitoring size structure in addition to abundance. Methodologically, the study demonstrates the value of hybrid workflows combining automated imaging with targeted manual curation. Despite challenges such as misclassification of transparent taxa and debris, semi-automated imaging proves scalable and essential for long-term ecological monitoring. Ultimately, the findings provide critical baseline data for understanding mesozooplankton dynamics under anomalous conditions. They highlight both resilience and vulnerability: while copepods persist, the productivity of short food chains may increasingly be at risk in a warming and more variable ocean.