Skip to Main content Skip to Navigation
Journal articles

Phosphorus limitation affects the molecular composition of Thalassiosira weissflogii leading to increased biogenic silica dissolution and high degradation rates of cellular carbohydrates

Abstract : Diatoms in general, and Thalassiosira weissflogii (T. weissflogii) in particular, are among the most ubiquitous phytoplanktonic species, while phosphorus (P) is an essential nutrient that limits productivity in many oceanic regimes. To investigate how T. weissflogii cultures grown under different P regimes are chemically altered before and during their prokaryotic degradation, T. weissflogii cells were cultivated under two contrasting P conditions; “P-stress” and “P-replete”. Biodegradation experiments were conducted in natural seawater comprising a natural prokaryotic community. The particulate fraction was monitored for 3 weeks for organic carbon (POC), nitrogen (PON), biogenic silica (bSiO2), total carbohydrates (PCHO) and individual monosaccharides, including prokaryotic counting. Results indicated that P-stress induced changes in the chemical composition of the T. weissflogii cells, causing a decrease in the Si/N (1.1–0.46) and Si/C (0.17–0.08) ratios. The “P-stress T. weissflogii” cells were characterized by high amounts of galactose (23% of PCHO), xylose (21%) and glucose (19%), compared to the “P-replete T. weissflogii” cells. The latter were dominated by ribose (20% of PCHO), further indicating the exhaustion of ribose-rich molecules (e.g., ATP) in T. weissflogii under “P-stress” conditions. The degradation experiments showed that bSiO2 produced under “P-stress” conditions dissolved more rapidly than bSiO2 formed under “P-replete” conditions, whereas POC and PON exhibited higher degradation rate constants in the “P-replete T. weissflogii” than in the “P-stress T. weissflogii” experiment. Overall, these observations show that submission of T. weissflogii to P-limitation results in changes in its initial biochemical composition, increased frustule dissolution rates, and decreases the degradation of T. weissflogii-organic matter by marine prokaryotes.
Complete list of metadatas

Cited literature [63 references]  Display  Hide  Download

https://hal.archives-ouvertes.fr/hal-02937026
Contributor : Christos Panagiotopoulos <>
Submitted on : Saturday, September 12, 2020 - 11:54:58 AM
Last modification on : Friday, September 18, 2020 - 3:40:08 PM

File

Pana et al. Org. Geochem. 2020...
Files produced by the author(s)

Identifiers

Citation

Christos Panagiotopoulos, Madeleine Goutx, Maxime Suroy, Brivaëla Moriceau. Phosphorus limitation affects the molecular composition of Thalassiosira weissflogii leading to increased biogenic silica dissolution and high degradation rates of cellular carbohydrates. Organic Geochemistry, Elsevier, 2020, 148, pp.104068. ⟨10.1016/j.orggeochem.2020.104068⟩. ⟨hal-02937026⟩

Share

Metrics

Record views

70

Files downloads

68