Microbial diversity-informed modelling of polar marine ecosystem functions

Abstract

Abstract. Heterotrophic marine bacteria utilize organic carbon for growth and biomass synthesis. Thus, their variability is key to the balance between the production and consumption of organic matter and ultimately particle export in the ocean. Here we investigate a potential link between bacterial traits and ecosystem functions in a rapidly changing polar marine ecosystem based on a bacteria-oriented ecosystem model. Using a data-assimilation scheme we utilize the observations of bacterial groups with different physiological states to constrain the group-specific bacterial ecosystem functions. We also investigate the association of the modelled bacterial and other ecosystem functions with eight recurrent modes representative of different bacterial taxonomic traits. High nucleic acid (HNA) bacteria show relatively high cell-specific bacterial production, respiration, and utilization of the semi-labile dissolved organic carbon pool compared to low nucleic acid (LNA) bacteria. Both taxonomy and physiological states of the bacteria are strong predictors of bacterial carbon demand, net primary production, and particle export. Numerical experiments under perturbed climate conditions show overall increased bacterial activity and a potential shift from LNA- to HNA-dominated bacterial communities in a warming ocean. Microbial diversity via different taxonomic and physiological traits informs our ecosystem model, providing insights into key bacterial and ecosystem functions in a changing environment.

Phytoplankton Responses to Bacterially Regenerated Iron in a Southern Ocean Eddy

“…High specific growth rates for LNA in nutrient-limited waters have contradicted this view in the past [63] and this marked discrepancy between the proportion of HNA and BP rates in our study is additional evidence that LNA bacteria are an active part of microbial communities. One additional explanation is a profound impact of specific grazing by microzooplankton on HNA cells' abundance [64,65]. Importantly, the BP results demonstrate that intense bacterial activity occurred in the eddy, which may have been supplemented with grazing to result in the rapid recycling of Fe (and the concurrent release of Fe-binding ligands) in the upper surface ocean.…”

Diversity and spatiotemporal variations in bacterial and archaeal communities within Kuwaiti territorial waters of the Northwest Arabian Gulf

“…Shotgun metagenomic sequencing also provides superior statistical power compared to 16S rRNA sequencing approaches [17]. Metagenomic profiling using a shotgun metagenomics approach permits prediction of individual community-and ecosystem-level responses to environmental disturbances via a tractable and simple workflow [18]. Importantly, establishment of a comprehensive profile of marine microbial communities within a given water body will provide the baseline information required to generate in silicobased prediction models, which will be invaluable for developing real time response criteria for local adverse events, such as mass death and disease of marine biota, harmful algal blooms, introduction of anthropogenic stressors, and global phenomena such as climate change [15,16,[19][20][21].…”