Microbial dinitrogen fixation in coral holobionts exposed to thermal stress and bleaching
Ulisse Cardini
Nanne van Hoytema
Vanessa N. Bednarz
Laura Rix
Rachel A. Foster
Mamoon M. D. Al-Rshaidat
Christian Wild
Abstract
Coral holobionts (i.e., coral‐algal‐prokaryote symbioses) exhibit dissimilar thermal sensitivities that may determine which coral species will adapt to global warming. Nonetheless, studies simultaneously investigating the effects of warming on all holobiont members are lacking. Here we show that exposure to increased temperature affects key physiological traits of all members (herein: animal host, zooxanthellae and diazotrophs) of both Stylophora pistillata and Acropora hemprichii during and after thermal stress. S. pistillata experienced severe loss of zooxanthellae (i.e., bleaching) with no net photosynthesis at the end of the experiment. Conversely, A. hemprichii was more resilient to thermal stress. Exposure to increased temperature (+ 6°C) resulted in a drastic increase in daylight dinitrogen (N2) fixation, particularly in A. hemprichii (threefold compared with controls). After the temperature was reduced again to in situ levels, diazotrophs exhibited a reversed diel pattern of activity, with increased N2 fixation rates recorded only in the dark, particularly in bleached S. pistillata (twofold compared to controls). Concurrently, both animal hosts, but particularly bleached S. pistillata, reduced both organic matter release and heterotrophic feeding on picoplankton. Our findings indicate that physiological plasticity by coral‐associated diazotrophs may play an important role in determining the response of coral holobionts to ocean warming.
Cardini U., van Hoytema N., Bednarz V.N., Rix L., Foster R.A., Al-Rshaidat M.M.D. and Wild C. (2016) Microbial dinitrogen fixation in coral holobionts exposed to thermal stress and bleaching. Environmental Microbiology 18(8): 2620-2633. 10.1111/1462-2920.13385
@article{Cardini2016,
Title = {Microbial dinitrogen fixation in coral holobionts exposed to thermal stress and bleaching},
Author = {Cardini, Ulisse and van Hoytema, Nanne and Bednarz, Vanessa N. and Rix, Laura and Foster, Rachel A. and Al-Rshaidat, Mamoon M. D. and Wild, Christian},
Editor = {},
Journal = {Environmental Microbiology},
Year = {2016},
Pages = {2620-2633},
Volume = {18},
Doi = {10.1111/1462-2920.13385},
Abstract = {Coral holobionts (i.e., coral‐algal‐prokaryote symbioses) exhibit dissimilar thermal sensitivities that may determine which coral species will adapt to global warming. Nonetheless, studies simultaneously investigating the effects of warming on all holobiont members are lacking. Here we show that exposure to increased temperature affects key physiological traits of all members (herein: animal host, zooxanthellae and diazotrophs) of both Stylophora pistillata and Acropora hemprichii during and after thermal stress. S. pistillata experienced severe loss of zooxanthellae (i.e., bleaching) with no net photosynthesis at the end of the experiment. Conversely, A. hemprichii was more resilient to thermal stress. Exposure to increased temperature (+ 6°C) resulted in a drastic increase in daylight dinitrogen (N2) fixation, particularly in A. hemprichii (threefold compared with controls). After the temperature was reduced again to in situ levels, diazotrophs exhibited a reversed diel pattern of activity, with increased N2 fixation rates recorded only in the dark, particularly in bleached S. pistillata (twofold compared to controls). Concurrently, both animal hosts, but particularly bleached S. pistillata, reduced both organic matter release and heterotrophic feeding on picoplankton. Our findings indicate that physiological plasticity by coral‐associated diazotrophs may play an important role in determining the response of coral holobionts to ocean warming.},
}
TY - JOUR
AU - Cardini, Ulisse
AU - van Hoytema, Nanne
AU - Bednarz, Vanessa N.
AU - Rix, Laura
AU - Foster, Rachel A.
AU - Al-Rshaidat, Mamoon M. D.
AU - Wild, Christian
TI - Microbial dinitrogen fixation in coral holobionts exposed to thermal stress and bleaching
T2 - Environmental Microbiology
PY - 2016
SP - 2620-2633
VL - 18
DO - 10.1111/1462-2920.13385
AB - Coral holobionts (i.e., coral‐algal‐prokaryote symbioses) exhibit dissimilar thermal sensitivities that may determine which coral species will adapt to global warming. Nonetheless, studies simultaneously investigating the effects of warming on all holobiont members are lacking. Here we show that exposure to increased temperature affects key physiological traits of all members (herein: animal host, zooxanthellae and diazotrophs) of both Stylophora pistillata and Acropora hemprichii during and after thermal stress. S. pistillata experienced severe loss of zooxanthellae (i.e., bleaching) with no net photosynthesis at the end of the experiment. Conversely, A. hemprichii was more resilient to thermal stress. Exposure to increased temperature (+ 6°C) resulted in a drastic increase in daylight dinitrogen (N2) fixation, particularly in A. hemprichii (threefold compared with controls). After the temperature was reduced again to in situ levels, diazotrophs exhibited a reversed diel pattern of activity, with increased N2 fixation rates recorded only in the dark, particularly in bleached S. pistillata (twofold compared to controls). Concurrently, both animal hosts, but particularly bleached S. pistillata, reduced both organic matter release and heterotrophic feeding on picoplankton. Our findings indicate that physiological plasticity by coral‐associated diazotrophs may play an important role in determining the response of coral holobionts to ocean warming.
ER -
