Archaeal blooms and busts in an estuarine time series

Abstract
Coastal bays, such as Delaware Bay, are highly productive, ecologically important transitions between rivers and the coastal ocean. They offer opportunities to investigate archaeal assemblages across seasons, with the exchange of water masses that occurs with tidal cycles, and in the context of variable organic matter quality. For a year-long estuarine, size-fractionated time series, we used amplicon sequencing, chemical measurements, and qPCR to follow archaeal groups through the seasons. We detected seasonally high abundances of Marine Group II archaea in summer months which correlate with indicators of phytoplankton production, although not phytoplankton biomass. Although previous studies have reported associations between Marine Group II archaea and particles, here they are almost entirely found in very small particles (0.22–0.7 μm), suggesting they are free-living cells. Populations of Nitrososphaeria did not vary with particle size or environmental conditions. Methanogens were significant fractions of archaeal sequences in large particles at low tide during winter months. Contrary to expectations, Nanoarchaeia were found predominantly in the free-living fraction despite the previous observation that they require an association with hosts. These results underscore the utility of time series studies in shallow, tidally mixed estuarine environments that capture variable conditions for understanding the ecology and biogeochemistry of planktic archaea.
Description
This is the peer reviewed version of the following article: Guider, J.T., Yoshimura, K.M., Block, K.R., Biddle, J.F. & Shah Walter, S.R. (2024) Archaeal blooms and busts in an estuarine time series. Environmental Microbiology, 26(2), e16584. Available from: https://doi.org/10.1111/1462-2920.16584, which has been published in final form at https://doi.org/10.1111/1462-2920.16584. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited. © 2024 Applied Microbiology International and John Wiley & Sons Ltd. This article will be embargoed until 02/07/2025.
Keywords
archaea, estuarine, coastal, time series, particles, free-living, Delaware Bay
Citation
Guider, J.T., Yoshimura, K.M., Block, K.R., Biddle, J.F. & Shah Walter, S.R. (2024) Archaeal blooms and busts in an estuarine time series. Environmental Microbiology, 26(2), e16584. Available from: https://doi.org/10.1111/1462-2920.16584