Allochthonous groundwater microorganisms affect coastal seawater microbial abundance, activity and diversity
Date:
Lecture / Seminar
Time: 11:00-12:00
Location: Sussman building
Abstract: Submarine groundwater discharge (SGD) is a globally important processsupplying n ... Read more Submarine groundwater discharge (SGD) is a globally important processsupplying nutrients and trace elements to the coastal environment, thusplaying a pivotal role in sustaining marine primary productivity. Along withnutrients, groundwater also contains allochthonous microbes that aredischarged from the terrestrial subsurface into the sea. Currently, little isknown about the interactions between groundwater-borne and coastalseawater microbial populations, and groundwater microbes' role uponintroduction to coastal seawater populations. In the current study weinvestigated seawater microbial abundance, activity and diversity in a sitestrongly influenced by SGD. In addition, through laboratory-controlledbottle incubations, we mimicked different mixing scenarios betweengroundwater and seawater. Our results demonstrate that the addition of0.1 μm filtered groundwater stimulated heterotrophic activity andincreased microbial abundance compared to control coastal seawater,whereas 0.22 μm filtration treatments induced primary productivity andSynechococcus growth. 16S rRNA gene sequencing showed a strongshift from a SAR11-rich community in the control samples toRhodobacteraceae dominance in the <0.1 μm treatment, in agreementwith Rhodobacteraceae enrichment in the SGD field site. These resultssuggest that microbes delivered by SGD may affect the abundance,activity and diversity of intrinsic microbes in coastal seawater, highlightingthe cryptic interplay between groundwater and seawater microbes incoastal environments, which has important implications for carboncycling.Close abstract
