The effects of variable riverine inputs and seasonal shifts in phytoplankton communities on nitrate cycling in a coastal lagoon

• DOI: 10.3389/fmars.2024.1497246
• Publication Date: 2024-12-23T05:10:29Z
• Authors: Mindaugas Zilius; Rūta Barisevičiūtė; Stefano Bonaglia; Isabell Klawonn; Elise Lorre; Tobia Politi; Irma Vybernaite-L...; Maren Voss; Donata Overlinge; Paul A. Bukaveckas
• Keywords: Biogeochemical Cycle; Dominance (genetics); Spring bloom; Nitrogen Cycle; Biogeochemistry; Cycling

Estuarine systems, being situated at the interface between land and marine environments, are important sites for nitrate (NO 3 – ) retention processing due to large inputs, long time, high biogeochemical activity. However, it remains uncertain how pelagic benthic processes control NO cycling relative importance of these is affected by seasonal changes in estuarine conditions. We measured suite governing Curonian Lagoon (Southeast Baltic Sea) during two time periods representing spring summer show that spring, dissimilatory assimilatory prevailed, while summer, dominated. During warming temperatures riverine nitrogen (N) inputs were associated with onset diatom blooms. N assimilation diatoms resulted delivery particulate organic matter benthos, resulting greater denitrification sediments a flux from water column sediments. In phytoplankton blooms buoyant cyanobacteria rates uptake dominated, export lagoon into sea. Given low dissolved inorganic concentrations indicates community possessed nutritional strategy efficiently utilize multiple forms rates. Overall, our findings diatom-dominated communities foster strong benthic-pelagic coupling, whereas dominance pelagic-based cycling. While this study sheds new light on mechanisms Lagoon, further spatiotemporal resolution recommended better represent variability include other lagoons comprehensive understanding shallow systems.