Ocean acidification altered microbial functional potential in the Arctic Ocean

Abstract

Ocean acidification (OA) has considerably changed the metabolism and structure of plankton communities in the ocean. Evaluation of the response of the marine bacterioplankton community to OA is critical for understanding the future direction of bacterioplankton‐mediated biogeochemical processes in the ocean. Understanding the diversity of functional genes is important for linking the microbial community to ecological and biogeochemical processes. However, the influence of OA on the functional diversity of bacterioplankton remains unclear. Using high‐throughput functional gene microarray technology (GeoChip 4), we investigated the functional gene structure and diversity of bacterioplankton under three different pCO2 levels (control: 175 μatm, medium: 675 μatm, and high: 1085 μatm) in a large Arctic Ocean mesocosm experiment. We observed a higher evenness of microbial functional genes under elevated pCO2 compared with under low pCO2. OA induced a more stable community as evaluated by decreased dissimilarity of functional gene structure with increased pCO2. Molecular ecological networks under elevated pCO2 became more complex and stable, supporting the central ecological tenet that complexity begets stability. In particular, increased average abundances were found under elevated pCO2 for many genes involved in key metabolic processes, including carbon degradation, methane oxidization, nitrogen fixation, dissimilatory nitrite/nitrate reduction, and sulfide reduction processes. Altogether, these results indicate a significant influence of OA on the metabolism potential of bacterioplankton in the Arctic Ocean. Consequently, our study suggests that biogeochemical cycling mediated by these microbes may be altered by the OA in the future.

Cascading, interactive, and indirect effects of climate change on aquatic communities, habitats, and ecosystems

“…It is a strength of this special issue to be representative of diverse habitats and scales, including alpine streams (Leathers et al 2023), wetlands of the North American Great Plains (Hu et al 2023), lakes (Hébert et al 2023; Katkov and Fussmann 2023; Su et al 2023), estuaries (Douglas et al 2023; Franzè et al 2023), tropical reefs (Lange et al 2023), and the arctic ocean (Ramondenc et al 2023), as well as diverse organisms, from single celled algal primary producers (Vrana et al 2023) to top consumers such as right whales (Meyer‐Gutbrod et al 2023). Moreover, contributions cover ecologically and climate‐relevant ranges of scales, including laboratory experimentation lasting days (Bomfim et al 2023; Carrier‐Bellau et al 2023, Fields et al 2023), mesocosm experiments of 1‐month duration (Katkov & Fussmann 2023; Wang et al 2023), as well as the paleorecord (Hu et al 2023). Despite this diversity of habitats and scales, the contributions to the special issue reflect only a subset of breadth, approaches, and geographic coverage; several gaps in contributions of climate‐oriented aquatic research are apparent.…”

“…Indirect effects were also considered in the Artic mesocosm study by Wang et al (2023) who examined pCO 2 effects on gene expression in marine microbes, bridging the gap from genes to ecosystem function. They explored potential effects of future pCO 2 states and the resulting ocean acidification by examining the responses of functional gene structure and diversity in bacterioplankton to elevated pCO 2 .…”