Nutrient consumption and chain tuning in diatoms exposed to storm-like turbulence

Abstract

Current information on the response of phytoplankton to turbulence is linked to cell size and nutrient availability. Diatoms are considered to be favored by mixing as dissolved nutrients are more easily accessible for non-motile cells. We investigated how diatoms exploit microscale turbulence under nutrient repletion and depletion conditions. Here, we show that the chain-forming diatom Chaetoceros decipiens, continues to take up phosphorus and carbon even when silicon is depleted during turbulence. Our findings indicate that upon silica depletion, during turbulence, chain spectra of C. decipiens remained unchanged. We show here that longer chains are maintained during turbulence upon silica depletion whereas under still conditions, shorter chains are enriched. We interpret this as a sign of good physiological state leading to a delay of culture senescence. Our results show that C. decipiens senses and responds to turbulence both in nutrient repletion and depletion. This response is noteworthy due to the small size of the species. The coupling between turbulence and biological response that we depict here may have significant ecological implications. Considering the predicted increase of storms in Northern latitudes this response might modify community structure and succession. Our results partly corroborate Margalef’s mandala and provide additional explanations for that conceptualization.

Role of nutrient concentrations and water movement on diatom’s productivity in culture

“…Our study reveals that in the conventional f/2 medium used for diatom’s cultivation 41 cells reach the stationary phase in parallel with the depletion of P and/or Si in agreement with previous studies 36,42 . PO 4 3− concentration dropped down to <0.1 µmol L −1 (Fig.…”

“…Using a wave marker pump instead of air-bubbling, growth rate was significantly higher (p < 0.01) compared to aeration (Fig. 3A), as reported by other studies 24,25,42,50 . While aeration ensures the exchanges between the medium and air thanks the addition of gas in the culture, water movement prevents sedimentation of the algae, ensures that cells are equally exposed to light 26 and that they continuously explore new microscale environments 24,25 with renewed nutrients composition/concentration, as well as improving gas exchange between the medium and the air.…”

RNA-seq and flow-cytometry of conventional, scalp, and palmoplantar psoriasis reveal shared and distinct molecular pathways

“…We believe that bulk RNA-seq does not provide sufficient resolution to detect cytokine expression differences across different T cell populations. Indeed, we have recently shown 42 that populations such as CD8+ T cells are not well represented in bulk RNA-seq analysis of skin tissue.…”

Selective chemoattraction of the benthic diatom Seminavis robusta to phosphate but not to inorganic nitrogen sources contributes to biofilm structuring

“…As dP‐starved diatoms only experience a moderate reduction in photosystem efficiency (Geider et al., ), they recover faster than dN‐starved cells. In contrast, dSi is only crucial for cell wall development, and limiting scenarios do not hamper carbon metabolism and nutrient uptake (Dell'Aquila et al., ). Thus, dSi‐starved cells reside in a better physiological state than the other two treatments and are ready to resume cell cycle once they encounter dSi.…”