scholarly journals Iron Limitation of a Springtime Bacterial and Phytoplankton Community in the Ross Sea: Implications for Vitamin B12 Nutrition

2011 ◽  
Vol 2 ◽  
Author(s):  
Erin M. Bertrand ◽  
Mak A. Saito ◽  
Peter A. Lee ◽  
Robert B. Dunbar ◽  
Peter N. Sedwick ◽  
...  
2020 ◽  
Vol 10 (19) ◽  
pp. 6965 ◽  
Author(s):  
Francesco Bolinesi ◽  
Maria Saggiomo ◽  
Serena Aceto ◽  
Angelina Cordone ◽  
Emanuela Serino ◽  
...  

We collected live mixed natural samples from the northeastern Ross Sea during the austral summer of 2017 and isolated a novel Prorocentrum sp. (Dinophyceae) associated with mucilaginous Phaeocystis antarctica (Coccolithophyceae) colonies. The haptophyte P. antarctica is a key species of the phytoplankton community in the Ross Sea, where blooms are subjected to iron limitation and/or co-limitation with other micronutrients (e.g., vitamin B12) during the summer. We first performed preliminary genetic analyses to determine the specific identity of the novel Prorocentrum sp., which indicated that it represented a previously undescribed species. The formal description of this new species is in process. To further assess its relationship with P. antarctica, we obtained their monospecific and mixed cultures and evaluated their responses to different irradiance levels and iron and vitamin B12 limitation. Our results indicated differential susceptibility of the two species to iron limitation and differential photosynthetic plasticity under high irradiance. Iron limitation reduced colony formation in P. antarctica and decreased the chlorophyll-a content in Prorocentrum sp., whereas B12 limitation did not affect growth or photosynthetic efficiency in either species. In addition, P. antarctica could photosynthesize efficiently under different irradiance levels, due to its ability to modulate the light adsorption cross-section of PSII, whereas Prorocentrum sp. exhibited lower photosynthetic plasticity and an inability to modulate both the maximum photochemical efficiency and effective adsorption cross-section of PSII under high irradiance. The trophic interaction between Prorocentrum sp. and P. antarctica could present ecological implications for the food webs and biogeochemical cycles of the Antarctic ecosystem. Considering the predicted climate-driven shifts in global ocean surface light regimes and changes in iron or vitamin B12 transfer, which are most likely to impact changes in the phytoplankton community structure, our results present implications for carbon export to deeper waters, ecological functioning, and associated biogeochemical changes in the future.


2011 ◽  
Vol 13 (5) ◽  
pp. 1285-1298 ◽  
Author(s):  
Erin M. Bertrand ◽  
Mak A. Saito ◽  
Young Jae Jeon ◽  
Brett A. Neilan

2000 ◽  
Vol 105 (C5) ◽  
pp. 11321-11336 ◽  
Author(s):  
Peter N. Sedwick ◽  
Giacomo R. DiTullio ◽  
Denis J. Mackey

2016 ◽  
Vol 13 (2) ◽  
pp. 293 ◽  
Author(s):  
Peter A. Lee ◽  
Erin M. Bertrand ◽  
Mak A. Saito ◽  
Giacomo R. DiTullio

Environmental context Cobalamin, or vitamin B12, is receiving increased attention as a critical trace nutrient in the growth and metabolic processes of oceanic phytoplankton and bacterial communities. We present evidence that indicates B12 has a more significant role in the biogeochemical cycling of the climatically important compounds dimethylsulfide and dimethylsulfoniopropionate than previously understood. Several possible mechanisms are examined that link cellular-level processes involving B12 to global-scale biogeochemical processes involving the oceanic cycling of dimethylsulfoniopropionate and dimethylsulfide. Abstract Evidence is presented showing that dissolved dimethylsulfoniopropionate (DMSPd) and dimethylsulfide (DMS) concentrations are influenced by the availability of vitamin B12 in two oceanographically distinct regions with different DMS production capacities, the central equatorial Pacific Ocean and the Ross Sea, Antarctica. In both locations, addition of B12 to incubation experiments resulted in decreases in DMS and, in some cases, DMSPd concentrations relative to unamended controls. In no case did increasing iron availability significantly (α=0.1) alter DMS concentrations relative to controls. The relative decreases in DMS between B12 addition and control experiments were significant (α=0.1) in five of seven experiments conducted at ambient iron levels. Overall, DMS concentrations were on average 33.4% (±15.1%; 1 standard deviation) lower, relative to unamended controls, by the end of incubation experiments when B12 was added. Declines in DMSPd were observed in three of five experiments. Similar trends were observed when B12 was added to iron-supplemented bottle incubation experiments (30.4±10.4% lower final DMS concentrations in +B12Fe treatments relative to +Fe treatments). Several possible molecular-level explanations exist for this link between B12 and DMS production, including potential B12 dependence of methyltransferase enzymes involved in both DMS and DMSP degradation. Although the enzymology of these reactions remains unclear, the relationships described here provide evidence for plausible mechanisms behind the microbial modulation of oceanic DMS.


2007 ◽  
Vol 52 (3) ◽  
pp. 1079-1093 ◽  
Author(s):  
Erin M. Bertrand ◽  
Mak A. Saito ◽  
Julie M. Rose ◽  
Christina R. Riesselman ◽  
Maeve C. Lohan ◽  
...  

2021 ◽  
Author(s):  
Angelina Cordone ◽  
Giuseppe D'Errico ◽  
Maria Magliulo ◽  
Francesco Bolinesi ◽  
Matteo Selci ◽  
...  

Primary productivity in the Ross Sea region is characterized by intense phytoplankton blooms whose temporal and spatial distribution are driven by changes in environmental conditions as well as interactions with the bacterioplankton community. Exchange of exudates, metabolism by-products and cofactors between the phytoplankton and the bacterioplankton communities drive a series of complex interactions affecting the micronutrient availability and co-limitation, as well as nutrient uptakes in Antarctic waters. Yet, the number of studies reporting the simultaneous diversity of the phytoplankton and bacterioplankton in Antarctic waters are limited. Here we report data on the bacterial diversity in relation to phytoplankton community in the surface waters of the Ross Sea during the austral summer 2017. Our results show partially overlapping bacterioplankton communities between the stations located in the Terra Nova Bay coastal waters and the Ross Sea open waters, suggesting that the two communities are subjected to different drivers. We show that the rate of diversity change between the two locations is influenced by both abiotic (salinity and the nitrogen to phosphorus ratio) and biotic (phytoplankton community structure) factors. Our data provides new insight into the coexistence of the bacterioplankton and phytoplankton in Antarctic waters.


Sign in / Sign up

Export Citation Format

Share Document