Publications by authors named "Dack Stuart"
Article Synopsis
- Seasonal changes in light and groundwater chemistry significantly impact the structure and function of cyanobacterial mats, particularly in the Middle Island Sinkhole (MIS).
- These changes lead to shifts in dominant cyanobacteria species, from Phormidium in summer to Planktothrix in autumn, accompanied by increased populations of diatoms and various sulfur-related bacteria.
- The presence of specialized light-harvesting proteins in cyanobacteria and higher abundance of Beggiatoa sulfur oxidation proteins in autumn suggest physiological adaptations to seasonal light variations, indicating strong interactions among different microbial groups affecting biogeochemical processes in these ecosystems.
Diatoms are among the few eukaryotes known to store nitrate (NO ) and to use it as an electron acceptor for respiration in the absence of light and O . Using microscopy and N stable isotope incubations, we studied the relationship between dissimilatory nitrate/nitrite reduction to ammonium (DNRA) and diel vertical migration of diatoms in phototrophic microbial mats and the underlying sediment of a sinkhole in Lake Huron (USA). We found that the diatoms rapidly accumulated NO at the mat-water interface in the afternoon and 40% of the population migrated deep into the sediment, where they were exposed to dark and anoxic conditions for ~75% of the day.
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