Horizontal distribution of marine microbial communities in the North Pacific Subtropical Front

Eva Lopes; Miguel Semedo; Maria Paola Tomasino; Renato Mendes; João Borges de Sousa; Catarina Magalhães

doi:10.3389/fmicb.2024.1455196

Horizontal distribution of marine microbial communities in the North Pacific Subtropical Front

Front Microbiol. 2024 Dec 24:15:1455196. doi: 10.3389/fmicb.2024.1455196. eCollection 2024.

Authors

Eva Lopes^{1

2}, Miguel Semedo², Maria Paola Tomasino², Renato Mendes^{3

4}, João Borges de Sousa⁴, Catarina Magalhães^{1

2}

Affiliations

¹ Faculty of Sciences, University of Porto, Porto, Portugal.
² Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), University of Porto, Matosinhos, Portugal.
³ +ATLANTIC CoLAB, Lisbon, Portugal.
⁴ Underwater Systems and Technology Laboratory (LSTS), LAETA, Faculty of Engineering, University of Porto, Porto, Portugal.

Abstract

Microbial communities are crucial for important ecosystem functions in the open ocean, such as primary production and nutrient cycling. However, few studies have addressed the distribution of microplankton communities in the remote oligotrophic region of the Pacific Ocean. Moreover, the biogeochemical and physical drivers of microbial community structure are not fully understood in these areas. This research aims to investigate the patterns of prokaryotic and protists communities' distribution in the North Pacific Subtropical Front (NPSF). The NPSF is a vast oligotrophic region with layered surface water and strong ocean currents. Despite its considerable size, its community distribution and function are poorly studied. We used a 16S and 18S rRNA gene sequencing approach to identify and characterize the water column microbial communities at two depths, the surface (3-5 m) and the deep chlorophyll maximum (DCM, 108-130 m). We aimed to elucidate the horizontal distribution patterns of these communities and to dissect the factors intricately shaping their distribution in the NPSF. Results showed that the community structure of both prokaryotes and protists was significantly influenced by depth, temperature, and longitude. Regarding alpha diversity, both communities presented a higher diversity at the surface. The prokaryotes also demonstrated to have a higher diversity in samples placed further east. The prokaryotes were dominated by Proteobacteria and Cyanobacteria, and the eukaryotic communities were dominated by Syndiniales. Combining biological and hydrographic data analysis showed the influence of vertical currents near the frontal jet in shaping the vertical distribution of both prokaryotic and protist communities. Even though most studies do not consider anomalies that emerge at each depth, these occurrences are capable of having a strong impact and influence on community structure. This study marks a significant advance in unraveling the intricate community structure and distribution dynamics of marine microbial communities within the North Pacific Ocean.

Keywords: North Pacific Subtropical Front; eukaryotes; horizontal distribution; longitude; prokaryotes.

Grants and funding

The authors declare that financial support was received for the research, authorship, and/or publication of this article. The authors acknowledge the support of the Schmidt Ocean Institute (SOI) for providing the R/V Falkor for a 3-week cruise within the “Exploring Fronts with Multiple Robots” expedition (https://schmidtocean.org/cruise/exploring_fronts_with_multiple_ aerialsurface-underwater-vehicles/). The Portuguese Science and Technology Foundation (FCT) funded this study through a grant to CM (2022.02983.PTDC), a fellowship to EL (2022.13574.BD), a CEEC contract to MS (2023.08554.CEECIND/CP2848/CT0004), and partially supported this research through the projects UIDB/04423/2020 and UIDB/04565/2020.