Deposit-feeding of Nonionellina labradorica (foraminifera) from an Arctic methane seep site and possible association with a methanotroph
Christiane Schmidt
Emmanuelle Geslin
Joan M. Bernhard
Charlotte LeKieffre
Mette Marianne Svenning
Helene Roberge
Magali Schweizer
Giuliana Panieri
Abstract
Several foraminifera are deposit feeders that consume organic detritus (dead particulate organic material with entrained bacteria). However, the role of such foraminifera in the benthic food web remains understudied. Foraminifera feeding on methanotrophic bacteria, which are 13C-depleted, may cause negative cytoplasmic and/or calcitic δ13C values. To test whether the foraminiferal diet includes methanotrophs, we performed a short-term (20 h) feeding experiment with Nonionellina labradorica from an active Arctic methane-emission site (Storfjordrenna, Barents Sea) using the marine methanotroph Methyloprofundus sedimenti and analysed N. labradorica cytology via transmission electron microscopy (TEM). We hypothesised that M. sedimenti would be visible post-experiment in degradation vacuoles, as evidenced by their ultrastructure. Sediment grains (mostly clay) occurred inside one or several degradation vacuoles in all foraminifers. In 24 % of the specimens from the feeding experiment degradation vacuoles also contained bacteria, although none could be confirmed to be the offered M. sedimenti. Observations of the apertural area after 20 h incubation revealed three putative methanotrophs, close to clay particles, based on bacterial ultrastructural characteristics. Furthermore, we noted the absence of bacterial endobionts in all examined N. labradorica but confirmed the presence of kleptoplasts, which were often partially degraded. In sum, we suggest that M. sedimenti can be consumed via untargeted grazing in seeps and that N. labradorica can be generally classified as a deposit feeder at this Arctic site.
Schmidt C., Geslin E., Bernhard J.M., LeKieffre C., Svenning M.M., Roberge H., Schweizer M. and Panieri G. (2022) Deposit-feeding of Nonionellina labradorica (foraminifera) from an Arctic methane seep site and possible association with a methanotroph. Biogeosciences 19(16): 3897-3909. 10.5194/bg-19-3897-2022
@article{Schmidt2022,
Title = {Deposit-feeding of Nonionellina labradorica (foraminifera) from an Arctic methane seep site and possible association with a methanotroph},
Author = {Schmidt, Christiane and Geslin, Emmanuelle and Bernhard, Joan M. and LeKieffre, Charlotte and Svenning, Mette Marianne and Roberge, Helene and Schweizer, Magali and Panieri, Giuliana},
Editor = {},
Journal = {Biogeosciences},
Year = {2022},
Pages = {3897-3909},
Volume = {19},
Doi = {10.5194/bg-19-3897-2022},
Abstract = {Several foraminifera are deposit feeders that consume organic detritus (dead particulate organic material with entrained bacteria). However, the role of such foraminifera in the benthic food web remains understudied. Foraminifera feeding on methanotrophic bacteria, which are 13C-depleted, may cause negative cytoplasmic and/or calcitic δ13C values. To test whether the foraminiferal diet includes methanotrophs, we performed a short-term (20 h) feeding experiment with Nonionellina labradorica from an active Arctic methane-emission site (Storfjordrenna, Barents Sea) using the marine methanotroph Methyloprofundus sedimenti and analysed N. labradorica cytology via transmission electron microscopy (TEM). We hypothesised that M. sedimenti would be visible post-experiment in degradation vacuoles, as evidenced by their ultrastructure. Sediment grains (mostly clay) occurred inside one or several degradation vacuoles in all foraminifers. In 24 % of the specimens from the feeding experiment degradation vacuoles also contained bacteria, although none could be confirmed to be the offered M. sedimenti. Observations of the apertural area after 20 h incubation revealed three putative methanotrophs, close to clay particles, based on bacterial ultrastructural characteristics. Furthermore, we noted the absence of bacterial endobionts in all examined N. labradorica but confirmed the presence of kleptoplasts, which were often partially degraded. In sum, we suggest that M. sedimenti can be consumed via untargeted grazing in seeps and that N. labradorica can be generally classified as a deposit feeder at this Arctic site.},
}
TY - JOUR
AU - Schmidt, Christiane
AU - Geslin, Emmanuelle
AU - Bernhard, Joan M.
AU - LeKieffre, Charlotte
AU - Svenning, Mette Marianne
AU - Roberge, Helene
AU - Schweizer, Magali
AU - Panieri, Giuliana
TI - Deposit-feeding of Nonionellina labradorica (foraminifera) from an Arctic methane seep site and possible association with a methanotroph
T2 - Biogeosciences
PY - 2022
SP - 3897-3909
VL - 19
DO - 10.5194/bg-19-3897-2022
AB - Several foraminifera are deposit feeders that consume organic detritus (dead particulate organic material with entrained bacteria). However, the role of such foraminifera in the benthic food web remains understudied. Foraminifera feeding on methanotrophic bacteria, which are 13C-depleted, may cause negative cytoplasmic and/or calcitic δ13C values. To test whether the foraminiferal diet includes methanotrophs, we performed a short-term (20 h) feeding experiment with Nonionellina labradorica from an active Arctic methane-emission site (Storfjordrenna, Barents Sea) using the marine methanotroph Methyloprofundus sedimenti and analysed N. labradorica cytology via transmission electron microscopy (TEM). We hypothesised that M. sedimenti would be visible post-experiment in degradation vacuoles, as evidenced by their ultrastructure. Sediment grains (mostly clay) occurred inside one or several degradation vacuoles in all foraminifers. In 24 % of the specimens from the feeding experiment degradation vacuoles also contained bacteria, although none could be confirmed to be the offered M. sedimenti. Observations of the apertural area after 20 h incubation revealed three putative methanotrophs, close to clay particles, based on bacterial ultrastructural characteristics. Furthermore, we noted the absence of bacterial endobionts in all examined N. labradorica but confirmed the presence of kleptoplasts, which were often partially degraded. In sum, we suggest that M. sedimenti can be consumed via untargeted grazing in seeps and that N. labradorica can be generally classified as a deposit feeder at this Arctic site.
ER -
