TY  - JOUR
A1  - Mestre, Mireia
A1  - Ferrera, Isabel
A1  - Borrull, Encarna
A1  - Ortega-Retuerta, Eva
A1  - Mbedi, Susan
A1  - Grossart, Hans-Peter
A1  - Gasol, Josep M.
A1  - Sala, M. Montserrat
T1  - Spatial variability of marine bacterial and archaeal communities along the particulate matter continuum
JF  - Molecular ecology
N2  - Biotic and abiotic particles shape the microspatial architecture that defines the microbial aquatic habitat, being particles highly variable in size and quality along oceanic horizontal and vertical gradients. We analysed the prokaryotic (bacterial and archaeal) diversity and community composition present in six distinct particle size classes ranging from the pico-to the microscale (0.2 to 200 lm). Further, we studied their variations along oceanographic horizontal (from the coast to open oceanic waters) and vertical (from the ocean surface into the meso-and bathypelagic ocean) gradients. In general, prokaryotic community composition was more variable with depth than in the transition from the coast to the open ocean. Comparing the six size-fractions, distinct prokaryotic communities were detected in each size-fraction, and whereas bacteria were more diverse in the larger size-fractions, archaea were more diverse in the smaller size-fractions. Comparison of prokaryotic community composition among particle size-fractions showed that most, but not all, taxonomic groups have a preference for a certain size-fraction sustained with depth. Species sorting, or the presence of diverse ecotypes with distinct size-fraction preferences, may explain why this trend is not conserved in all taxa.
KW  - attached
KW  - free-living
KW  - particulate matter
KW  - prokaryotic community
KW  - spatial variability
Y1  - 2017
U6  - https://doi.org/10.1111/mec.14421
SN  - 0962-1083
SN  - 1365-294X
VL  - 26
SP  - 6827
EP  - 6840
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Beisner, Beatrix E.
A1  - Grossart, Hans-Peter
A1  - Gasol, Josep M.
T1  - A guide to methods for estimating phago-mixotrophy in nanophytoplankton
JF  - Journal of plankton research
N2  - Growing attention to phytoplankton mixotrophy as a trophic strategy has led to significant revisions of traditional pelagic food web models and ecosystem functioning. Although some empirical estimates of mixotrophy do exist, a much broader set of in situ measurements are required to (i) identify which organisms are acting as mixotrophs in real time and to (ii) assess the contribution of their heterotrophy to biogeochemical cycling. Estimates are needed through time and across space to evaluate which environmental conditions or habitats favour mixotrophy: conditions still largely unknown. We review methodologies currently available to plankton ecologists to undertake estimates of plankton mixotrophy, in particular nanophytoplankton phago-mixotrophy. Methods are based largely on fluorescent or isotopic tracers, but also take advantage of genomics to identify phylotypes and function. We also suggest novel methods on the cusp of use for phago-mixotrophy assessment, including single-cell measurements improving our capacity to estimate mixotrophic activity and rates in wild plankton communities down to the single-cell level. Future methods will benefit from advances in nanotechnology, micromanipulation and microscopy combined with stable isotope and genomic methodologies. Improved estimates of mixotrophy will enable more reliable models to predict changes in food web structure and biogeochemical flows in a rapidly changing world.
KW  - flow cytometry
KW  - phagotrophy
KW  - phytoplankton
KW  - methods
KW  - fluorescence
KW  - microscopy
KW  - FISH
KW  - isotopic methods
KW  - phylotypes
KW  - carbon flows
KW  - gene sequencing
Y1  - 2019
U6  - https://doi.org/10.1093/plankt/fbz008
SN  - 0142-7873
SN  - 1464-3774
VL  - 41
IS  - 2
SP  - 77
EP  - 89
PB  - Oxford Univ. Press
CY  - Oxford
ER  -