Carbon fixation by the phytoplankton community across Lake Winnipeg

2021 ◽  
Author(s):  
Yekaterina Yezhova ◽  
David Capelle ◽  
Michael Stainton ◽  
Tim Papakyriakou
Keyword(s):  
Phytoplankton Community ◽  
Carbon Fixation ◽  
Lake Winnipeg

Primary productivity induced by iron and nitrogen in the Tasman Sea: an overview of the PINTS expedition

2014 ◽  
Vol 65 (6) ◽  
pp. 517 ◽  
Author(s):  
C. S. Hassler ◽  
K. R. Ridgway ◽  
A. R. Bowie ◽  
E. C. V. Butler ◽  
L. A. Clementson ◽  
...  
Keyword(s):  
Phytoplankton Community ◽  
Carbon Fixation ◽  
Light Limitation ◽  
Atmospheric Nitrogen ◽  
The North ◽  
Tasman Sea ◽  
Limiting Nutrient ◽  
Particulate Nutrients ◽  
Atmospheric Nitrogen Fixation

The Tasman Sea and the adjacent subantarctic zone (SAZ) are economically important regions, where the parameters controlling the phytoplankton community composition and carbon fixation are not yet fully resolved. Contrasting nutrient distributions, as well as phytoplankton biomass, biodiversity and productivity were observed between the North Tasman Sea and the SAZ. In situ photosynthetic efficiency (FV/FM), dissolved and particulate nutrients, iron biological uptake, and nitrogen and carbon fixation were used to determine the factor-limiting phytoplankton growth and productivity in the North Tasman Sea and the SAZ. Highly productive cyanobacteria dominated the North Tasman Sea. High atmospheric nitrogen fixation and low nitrate dissolved concentrations indicated that non-diazotroph phytoplankton are nitrogen limited. Deck-board incubations also suggested that, at depth, iron could limit eukaryotes, but not cyanobacteria in that region. In the SAZ, the phytoplankton community was dominated by a bloom of haptophytes. The low productivity in the SAZ was mainly explained by light limitation, but nitrogen, silicic acid as well as iron were all depleted to the extent that they could become co-limiting. This study illustrates the challenge associated with identification of the limiting nutrient, as it varied between phytoplankton groups, depths and sites.

Comparing apples to oranges: Perspectives on satellite-based primary production estimates drawn from a global biogeochemical model

2019 ◽  
Vol 77 (2) ◽  
pp. 259-282
Author(s):  
Charles A. Stock
Keyword(s):  
Primary Production ◽  
Nutrient Limitation ◽  
Phytoplankton Community ◽  
Carbon Fixation ◽  
Size Structure ◽  
Net Primary Production ◽  
Maximum Growth ◽  
Inhibitory Effect ◽  
Biogeochemical Model ◽  
Small Phytoplankton

Net primary production (NPP) by microscopic phytoplankton underpins nearly all marine life, yet global NPP estimates differ substantially. Among satellite-based estimates, variation has been attributed to differing assumptions about the relationships between photosynthesis and sea surface temperature (SST). Maximum chlorophyll (Chl)–specific rates of carbon fixation in the water column (PBopt) increase monotonically with SST in some satellite algorithms, whereas others peak at intermediate values. Understanding and constraining such relationships is challenged by the many direct and indirect relationships between temperature and phytoplankton. In this article, the emergent PBopt-SST relationship was diagnosed in a global biogeochemical simulation and compared with widely used satellite NPP algorithms. The simulated PBopt-SST relationship for the aggregated phytoplankton community was highly significant (r2= 0.83) and increased monotonically with temperature. The PBopt-SST relationships for small and large phytoplankton, however, were distinct and weaker than the aggregate relationship (r2 = 0.52 and 0.36, respectively). For small phytoplankton, the inhibitory effect of nutrient limitation in warmer, more stratified waters was moderated by efficient nutrient scavenging. This, combined with photoacclimation and the stimulatory effect of warming on maximum growth produced steep PBopt increases with SST. For large phytoplankton, the need for higher Chl:C in productive regions (because of package effects) and the onset of severe nutrient limitation in warm, stratified regions decreased PBopt relative to small phytoplankton, though PBopt still increased modestly with SST. The PBopt-SST relationships for both small and large phytoplankton overestimated PBopt in nutrient-poor regions and underestimated it in nutrient-rich regions. This bias was greatly reduced in the aggregate relationship because the increased prominence of low-PBopt large phytoplankton in nutrient-rich environments tempered PBopt increases. Results support a strong, monotonically increasing PBopt-SST relationship but emphasize the role of the size structure of the phytoplankton community in shaping the emergent relationship. The implications of these results are discussed in relation to efforts to improve satellite NPP algorithms and partition NPP by phytoplankton size.

Sectioned rubisco crystals in TEM

1990 ◽  
Vol 48 (3) ◽  
pp. 664-665
Author(s):  
Gunnel Karlsson ◽  
Jan-Olov Bovin ◽  
Michael Bosma
Keyword(s):  
Plant Cell ◽  
Carbon Fixation ◽  
Unit Cell ◽  
Protein Crystals ◽  
Unit Cell Parameters ◽  
Cell Parameters ◽  
Photosynthetic Carbon Fixation ◽  
Photosynthetic Carbon

RuBisCO (D-ribulose-l,5-biphosphate carboxylase/oxygenase) is the most aboundant enzyme in the plant cell and it catalyses the key carboxylation reaction of photosynthetic carbon fixation, but also the competing oxygenase reaction of photorespiation. In vitro crystallized RuBisCO has been studied earlier but this investigation concerns in vivo existance of RuBisCO crystals in anthers and leaves ofsugarbeets. For the identification of in vivo protein crystals it is important to be able to determinethe unit cell of cytochemically identified crystals in the same image. In order to obtain the best combination of optimal contrast and resolution we have studied different staining and electron accelerating voltages. It is known that embedding and sectioning can cause deformation and obscure the unit cell parameters.

Seasonal changes in phytoplankton community structure in a bioluminescent lagoon, St. Croix, US Virgin Islands

2018 ◽  
Vol 81 (2) ◽  
pp. 109-124 ◽  
Author(s):  
JL Pinckney ◽  
C Tomas ◽  
DI Greenfield ◽  
K Reale-Munroe ◽  
B Castillo ◽  
...  
Keyword(s):  
Community Structure ◽  
Seasonal Changes ◽  
Phytoplankton Community ◽  
Virgin Islands ◽  
Phytoplankton Community Structure ◽  
Us Virgin Islands

The Response of a Phytoplankton Community to Ecosystem Restoration in Huizhou West Lake

2010 ◽  
Vol 30 (4) ◽  
pp. 453-459
Author(s):  
Liang CHEN ◽  
Xiu-Feng ZHANG ◽  
Zheng-Wen LIU
Keyword(s):  
Phytoplankton Community ◽  
Ecosystem Restoration ◽  
West Lake

ALGAE AND PROGRESS IN PHOTOSYNTHESIS RESEARCH I-Oxygen evolution and carbon fixation

2000 ◽  
Vol 1 (1) ◽  
pp. 235-244
Author(s):  
Ahmed Hamad ◽  
Mohamed Osman ◽  
Refaat Abdel-Basset
Keyword(s):  
Oxygen Evolution ◽  
Carbon Fixation ◽  
Photosynthesis Research
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