@article {croteau_shifts_2022,
	title = {Shifts in growth light optima among diatom species support their succession during the spring bloom in the Arctic},
	journal = {Journal of Ecology},
	volume = {n/a},
	number = {n/a},
	year = {2022},
	note = {_eprint: https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2745.13874},
	abstract = {1. Diatoms of the Arctic Ocean annually experience extreme changes of light environment linked to photoperiodic cycles and seasonal variations of the snow and sea-ice cover extent and thickness which attenuate light penetration in the water column. Arctic diatom communities exploit this complex seasonal dynamic through a well-documented species succession during spring, beginning in sea-ice and culminating in massive phytoplankton blooms underneath sea-ice and in the marginal ice zone. The pattern of diatom taxa sequentially dominating this succession is relatively well conserved interannually, and taxonomic shifts seem to align with habitat transitions. 2. To understand whether differential photoadaptation strategies among diatom taxa explain these recurring succession sequences, we coupled lab experiments with field work in Baffin Bay at 67.5{\textdegree}N. Based on field data, we selected five diatom species typical of different ecological niches and measured their growth rates under light intensity ranges representative of their natural habitats. To characterize their photoacclimative responses, we sampled pigments and total particulate carbon, and conducted 14C-uptake photosynthesis response curves and variable fluorescence measurements. 3. We documented a gradient in species respective light intensity for maximal growth suggesting divergent light response plasticity, which for the most part align with species sequential dominance. Other photophysiological parameters supported this ecophysiological framing, although contrasts were always clear only between succession endmembers, Nitzschia frigida and Chaetoceros neogracilis. To validate that these photoacclimative responses are representative of in situ dynamics, we compared them to the chlorophyll a-specific light-limited slope (α*) and saturated rate of photosynthesis (P*M), monitored in Baffin Bay on sea-ice and planktonic communities. This complementary approach confirmed that unusual responses in α* and P*M as a function of light history intensity are similar between sentinel sympagic species N. frigida and natural ice-core communities. While no light-history-dependent trends were observed in planktonic communities, their α* and P*M values were in the range of measurements from our monospecific cultures. 4. Synthesis. Our results suggest that Arctic diatoms species photoadaptation strategy is tuned to the light environment of the habitats in which they dominate and indeed drives the seasonal taxonomic succession.},
	keywords = {Arctic Ocean, diatoms, Ecophysiology, photoacclimation, photoadaptation, primary production, RCC2046, RCC2278, seasonal species succession, spring bloom},
	issn = {1365-2745},
	doi = {10.1111/1365-2745.13874},
	url = {http://onlinelibrary.wiley.com/doi/abs/10.1111/1365-2745.13874},
	author = {Croteau, D. and Lacour, T. and Schiffrine, N. and Morin, P.-I. and Forget, M.-H. and Bruyant, F. and Ferland, J. and Lafond, A. and Campbell, D. A. and Tremblay, J.-E. and Babin, M. and Lavaud, J.}
}
@article {Tisserand2020,
	title = {Use of organic exudates from two polar diatoms by bacterial isolates from the Arctic Ocean},
	journal = {Philosophical transactions. Series A, Mathematical, physical, and engineering sciences},
	volume = {378},
	number = {2181},
	year = {2020},
	note = {Publisher: NLM (Medline) tex.mendeley-tags: RCC2278,RCC4289},
	month = {oct},
	pages = {20190356},
	abstract = {Global warming affects primary producers in the Arctic, with potential consequences for the bacterial community composition through the consumption of microalgae-derived dissolved organic matter (DOM). To determine the degree of specificity in the use of an exudate by bacterial taxa, we used simple microalgae-bacteria model systems. We isolated 92 bacterial strains from the sea ice bottom and the water column in spring-summer in the Baffin Bay (Arctic Ocean). The isolates were grouped into 42 species belonging to Proteobacteria, Bacteroidetes, Actinobacteria and Firmicutes. Forty strains were tested for their capacity to grow on the exudate from two Arctic diatoms. Most of the strains tested (78\%) were able to grow on the exudate from the pelagic diatom Chaetoceros neogracilis, and 33\% were able to use the exudate from the sea ice diatom Fragilariopsis cylindrus. 17.5\% of the strains were not able to grow with any exudate, while 27.5\% of the strains were able to use both types of exudates. All strains belonging to Flavobacteriia (n = 10) were able to use the DOM provided by C. neogracilis, and this exudate sustained a growth capacity of up to 100 times higher than diluted Marine Broth medium, of two Pseudomonas sp. strains and one Sulfitobacter strain. The variable bioavailability of exudates to bacterial strains highlights the potential role of microalgae in shaping the bacterial community composition. This article is part of the theme issue {\textquoteright}The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning{\textquoteright}.},
	keywords = {Arctic Ocean, bacterial diversity, bacterial isolation, biodegradation, diatoms, dissolved organic exudates, RCC2278, RCC4289},
	issn = {14712962},
	doi = {10.1098/rsta.2019.0356},
	url = {https://royalsocietypublishing.org/doi/10.1098/rsta.2019.0356},
	author = {Tisserand, Lucas and Dadaglio, La{\"e}titia and Intertaglia, Laurent and Catala, Philippe and Panagiotopoulos, Christos and Obernosterer, Ingrid and Joux, Fabien}
}
