Baltic Sea coastal sediment-bound eukaryotes have increased year-round activities under predicted climate change related warming

Songjun Li; Emelie Nilsson; Laura Seidel; Marcelo Ketzer; Anders Forsman; Mark Dopson; Samuel Hylander

doi:10.3389/fmicb.2024.1369102

Baltic Sea coastal sediment-bound eukaryotes have increased year-round activities under predicted climate change related warming

Front Microbiol. 2024 Mar 26:15:1369102. doi: 10.3389/fmicb.2024.1369102. eCollection 2024.

Authors

Songjun Li¹, Emelie Nilsson¹, Laura Seidel^{1

2}, Marcelo Ketzer³, Anders Forsman¹, Mark Dopson¹, Samuel Hylander¹

Affiliations

¹ Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, Kalmar, Sweden.
² Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden.
³ Department of Biology and Environmental Sciences, Linnaeus University, Kalmar, Sweden.

Abstract

Climate change related warming is a serious environmental problem attributed to anthropogenic activities, causing ocean water temperatures to rise in the coastal marine ecosystem since the last century. This particularly affects benthic microbial communities, which are crucial for biogeochemical cycles. While bacterial communities have received considerable scientific attention, the benthic eukaryotic community response to climate change remains relatively overlooked. In this study, sediments were sampled from a heated (average 5°C increase over the whole year for over 50 years) and a control (contemporary conditions) Baltic Sea bay during four different seasons across a year. RNA transcript counts were then used to investigate eukaryotic community changes under long-term warming. The composition of active species in the heated and control bay sediment eukaryotic communities differed, which was mainly attributed to salinity and temperature. The family level RNA transcript alpha diversity in the heated bay was higher during May but lower in November, compared with the control bay, suggesting altered seasonal activity patterns and dynamics. In addition, structures of the active eukaryotic communities varied between the two bays during the same season. Hence, this study revealed that long-term warming can change seasonality in eukaryotic diversity patterns. Relative abundances and transcript expression comparisons between bays suggested that some taxa that now have lower mRNA transcripts numbers could be favored by future warming. Furthermore, long-term warming can lead to a more active metabolism in these communities throughout the year, such as higher transcript numbers associated with diatom energy production and protein synthesis in the heated bay during winter. In all, these data can help predict how future global warming will affect the ecology and metabolism of eukaryotic community in coastal sediments.

Keywords: RNA transcripts; community structure; diversity; functional activity; marine.

Grants and funding

The authors declare financial support was received for the research, authorship, and/or publication of this article. The authors thank the Swedish Research Council for Sustainable Development, Formas (contract FR-2020/0008) to MD; the Swedish Research Council, Vetenskaprådet (contract 2020-03519) and the Magnus Bergvalls Stiftelse (Grant No. 2019-03116) to AF; The Crafoord Foundation (Grant No. 20170539) to SH; and the Swedish Research Council for Sustainable Development, Formas (contract 2022-01016_3) to MK. The computations were enabled by resources (projects NAISS 2023/22-893 and 2023/6-261) provided by the Swedish National Infrastructure for Computing (SNIC) at UPPMAX at Uppsala University, partially funded by the Swedish Research Council through grant agreement No. 2018-05973. A portion of this research was performed under the Facilities Integrating Collaborations for User Science (FICUS) initiative and used resources at the DOE Joint Genome Institute and the Environmental Molecular Sciences Laboratory, which are DOE Office of Science User Facilities. Both facilities are sponsored by the Office of Biological and Environmental Research and operated under Contract Nos. DE-AC02-05CH11231 (JGI) and DE-AC05-76RL01830 (EMSL) via a CSP FY18 Q3 New Investigator Proposal (CSP 503869) to SH. Open access funding provided by Linnaeus University.