NITROGEN FIXATION IN SHALLOW LAGOONS: RATES, PALYERS AND IMPORTANCE IN NITROGEN CYCLING
Lagoons, being situated at the interface between land and marine environments, are potentially important sites for nitrogen (N) turnover due to long retention time and high biogeochemical rates. Most river-dominated lagoons shift toward N limitation in summer, creating favorable conditions for opportunistic microorganisms capable of fixing dissolved dinitrogen (N2). This N-cycling pathway may allow ecosystems to overcome N limitation and maintain high biomass in the water column while adding surplus N. However, the magnitude of N2 fixation is not well constrained in lagoons. Here, we used N isotope tracing and functional genomics to unravel N2 fixation in the three largest European lagoons (Curonian, Vistula and Oder) and elucidate its contribution to ecosystems. Overall, transcriptome analysis shows that diazotrophic communities are active in both sediments and water, with the highest activity during summer compared to cold spring season. The results further indicate that N2 fixation is higher in the euphotic layer of the water column than in dark aphotic layer or sediments. The importance of N fixation to the lagoon N budget varied widely depending on the system and diazotrophic community composition. Nonetheless, some general patterns emerge, such as diazotrophic activity was observed across all seasons, and transcript numbers were considered high even in sediments which are generally not N-limited.
Primary Presenter: Mindaugas Zilius, Klaipeda University (mindaugas.zilius@jmtc.ku.lt)
Authors:
Elias Broman, Stockholm University (elias.broman@su.se)
Paul Bukaveckas, Center for Environmental Studies, Virginia Commonwealth Universit (pabukaveckas@vcu.edu)
Francisco Nascimento, Stockholm University (Francisco.Nascimento@su.se)
Maren Voss, Leibniz Institute for Baltic Sea Research (maren.voss@io-warnemuende.de)
Aurelija Samuiloviene, Klaipeda University (aurelija.samuiloviene@ku.lt)
Irma Vybernaite-Lubiene, Klaipeda University (irma.vybernaite-lubiene@ku.lt)
Anastasija Zaiko, Sequench (a.zaiko@sequench.co.nz)
Steafno Bonaglia, University of Gothenburg (stefano.bonaglia@gu.se)
NITROGEN FIXATION IN SHALLOW LAGOONS: RATES, PALYERS AND IMPORTANCE IN NITROGEN CYCLING
Category
Scientific Sessions > SS14 - Exploring Nitrogen Fixation Along the Freshwater-Marine Continuum; A Joint ASLO-SFS Endeavor
Description
Time: 02:15 PM
Date: 4/6/2024
Room: Lecture Hall