Thread by @biolumiJEFFence

New paper out today in Limnology & Oceanography (@aslo_org) led by all-around great guy & scientist Mike Coffin!

“The killer within: Endogenous bacteria accelerate oyster mortality during sustained anoxia”

aslopubs.onlinelibrary.wiley.com/doi/full/10.10…

In a suite of experiments comparing #oysters treated w/ antibiotics vs. not, we demonstrate that bacteria endogenous to oysters accelerate mortality rates

The 3-year project was triggered by mass mortality of cultured oysters in 2016, seemingly linked to a period of low O₂

Generally, we found that oysters treated w/ antibiotics (chloramphenicol) lived approx. twice as long as those not treated with antibiotics

Oyster density appeared to have no effect on mortality rates under anoxia

Moribund/post-mortem histology confirmed the presence of bacteria in tissues of untreated oysters and a general lack thereof in antibiotic-treated oysters

Next-gen sequencing failed to identify a particular type of bacteria associate w/ mortality, but a diverse array of endogenous anaerobic & sulfate-reducing bacteria were common

We also monitored valve gaping behaviour in the lab (1st image) & field (2nd image) during anoxia, showing that oysters exhibit remarkable valve closure synchrony when initially exposed to anoxia, but individualized periodic openings thereafter

Overall, our results + previous studies strongly suggest that anoxia-related mass mortality events in bivalves are likely the result of co-morbidity from asphyxiation & bacterial processes

The results provide important information for understanding mechanisms of mortality as the frequency & severity of coastal anoxic/hypoxic events continues to increase

science.sciencemag.org/content/359/63…