Bio-optical modelling of primary production in the SW Finnish coastal zone, Baltic Sea: fast repetition rate fluorometry in Case 2 waters

Raateoja, Mika; Seppälä, Jukka; Kuosa, Harri

doi:10.3354/meps267009

Cited by 47 publications

(56 citation statements)

References 67 publications

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“…An increasing number of FRR-based investigations demonstrate that microalgal productivity is highly variable in nature (Moore et al, 2003;Raateoja et al, 2004;Smyth et al, 2004). Our investigation reinforces recent observations that knowledge of RCII concentration is key for accurately characterising the true variability of PSII light absorption and thus calculating absolute ETRs (Suggett et al, , 2004 and interpreting photophysiological processes (Suggett et al, 2004;Moore et al, 2005Moore et al, , 2006.…”

Section: Discussionsupporting

confidence: 76%

“…However, consideration of corresponding changes of light absorption, maximum ETRs and the light saturation parameter, E k , and of differences between ETRs and previous C-based measurements of P max demonstrate that photochemistry may not be tightly coupled with C uptake throughout these environments. Understanding this coupling is crucial for the development of bio-optical models that can accurately predict C-fixation Raateoja et al, 2004). Therefore, it is clear that more attention must be directed towards the differences in coupling between ETR and C-fixation that we have observed for the vast tropical and subtropical oceanic environments.…”

Section: Discussionmentioning

confidence: 99%

“…One such induction technique, Fast Repetition Rate (FRR) fluorescence (Kolber et al, 1998), has become widely used by oceanographers as it avoids the need to incubate discrete water samples and is highly sensitive. However, despite these benefits, relatively few FRR fluorescence-based measurements of marine primary productivity have been reported (Suggett et al, 2001;Moore et al, 2003;Raateoja et al, 2004;Smyth et al, 2004) and little is known of the variability of ETRs in oligotrophic subtropical and tropical oceanic environments.…”

Section: Introductionmentioning

confidence: 99%

“…Firstly, it has been problematic to reconcile FRR determinations of ETR with conventional O 2 evolution or C uptake productivity measurements Raateoja et al, 2004). ETRs are a direct measure of the potential to split water and hence of O 2 production, provided that the maximum quantum yield of O 2 evolution remains unchanged (Kromkamp and Forster, 2003).…”

Section: Introductionmentioning

confidence: 99%

“…Also, we can correct for the spectral weighting of FRRexcitation Suggett et al, 2001;Raateoja et al, 2004) and obtain some knowledge of the RCII concentration indirectly (Suggett et al, 2001(Suggett et al, , 2004Moore et al, 2005) provided additional bio-optical and/or biophysical properties of the PSII antenna-reaction centre complex are measured.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Photosynthetic electron turnover in the tropical and subtropical Atlantic Ocean

Suggett

Moore

Marañón

et al. 2006

Deep Sea Research Part II: Topical Studies in Oceanography

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Photosynthetic electron transport directly generates the energy required for carbon fixation and thus underlies the aerobic metabolism of aquatic systems. We determined photosynthetic electron turnover rates, ETRs, from ca. 100 FRR fluorescence water-column profiles throughout the subtropical and tropical Atlantic during six Atlantic Meridional Transect cruises (AMT 6, May-June 1998, to AMT 11, September-October 2000. Each FRR fluorescence profile yielded a water-column ETR-light response from which the maximum electron turnover rate ðETR max RCII Þ, effective absorption (s PSII ) and light saturation parameter (E k ) specific to the concentration of photosystem II reaction centres (RCIIs) were calculated. ETR max RCII and E k increased whilst s PSII decreased with mixed-layer depth and the daily integrated photosynthetically active photon flux when all provinces were considered together. These trends suggested that variability in maximum ETR can be partly attributed to changes in effective absorption. Independent bio-optical measurements taken during AMT 11 demonstrated that s PSII variability reflects taxonomic and physiological differences in the phytoplankton communities. ETR max RCII and E k , but not s PSII , remained correlated with mixed-layer depth and daily integrated photosynthetically active photon flux when data from each oceanic province were considered separately, indicating a decoupling of electron turnover and carbon fixation rates within each province. Comparison of maximum ETRs with 14 C-based measurements of P max further suggests that light absorption and C fixation are coupled to differing extents for the various oligotrophic Atlantic provinces. We explore the importance of quantifying RCII concentration for determination of ETRs and interpretation of ETR-C fixation coupling. r

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Section: Discussionsupporting

confidence: 76%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Photosynthetic electron turnover in the tropical and subtropical Atlantic Ocean

Suggett

Moore

Marañón

et al. 2006

Deep Sea Research Part II: Topical Studies in Oceanography

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Primary productivity and the coupling of photosynthetic electron transport and carbon fixation in the Arctic Ocean

Schuback

Hoppe

Tremblay

et al. 2017

Limnology & Oceanography

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We examined the light absorption properties and light-dependent rates of photosynthetic electron transport (ETR RCII ) and 14 C-uptake in phytoplankton of the Canadian Subarctic and Arctic Ocean. Our results reveal high variability in the light-saturated, chlorophyll a-specific rate of 14 C-uptake (P Chla max ; 0.7 to 8.0 mg C mg chl a 21 h 21 ) , and the light-dependant efficiency of 14 C-uptake (a Chla ; 0.01 to 0.09 mg C mg Chl a 21 h 21 [lmol quanta m 22 s 21 ] 21 ). Variability in P Chla max correlated with light availability in the stratified watercolumn, while both P Chla max and a Chla were correlated to the degree of nitrate depletion in the mixed layer. For all samples, we observed that 14 C-uptake rates reached light saturation at lower irradiances than ETR RCII , leading to significant, light-dependent de-coupling of carbon fixation and photosynthetic electron transport. For samples taken from within the mixed layer, we found that the conversion factor from ETR RCII to carbon fixation was strongly correlated to the magnitude of non-photochemical quenching, as derived from fast repetition rate fluorometry (FRRF) measurements. This correlation supports recent findings from the Subarctic Pacific Ocean, and has the potential to improve FRRF-based estimates of phytoplankton carbon fixation. Our observations reveal distinct environmental regulation of phytoplankton light absorption, electron transport and carbon fixation in phytoplankton assemblages within and below the shallow summer mixed layer, and will help to inform more robust predictions of future primary production in a rapidly changing Arctic Ocean.

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Seasonal regulation of the coupling between photosynthetic electron transport and carbon fixation in the Southern Ocean

Ryan‐Keogh

Thomalla

Little

et al. 2018

Limnology & Oceanography

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Active fluorescence measurements can provide rapid, non‐intrusive estimates of phytoplankton primary production at high spatial and temporal resolution, but there is uncertainty in converting from electrons to ecologically relevant rates of CO2 assimilation. In this study, we examine the light‐dependent rates of photosynthetic electron transport and 13C‐uptake in the Atlantic sector of the Southern Ocean to derive a conversion factor for both winter (July 2015–August 2015) and summer (December 2015–February 2016). The results revealed significant seasonal differences in the light‐saturated chlorophyll specific rate of 13C‐uptake, ( PmaxnormalB), with mean summer values 2.3 times higher than mean winter values, and the light limited chlorophyll specific efficiency, (αB), with mean values 2.7 times higher in summer than in winter. Similar patterns were observed in the light‐saturated photosynthetic electron transport rates ( ETRmaxRCII, 1.5 times higher in summer) and light limited photosynthetic electron transport efficiency (αRCII, 1.3 times higher in summer). The conversion factor between carbon and electrons (Φe:C (mol e− mol C−1)) was derived utilizing in situ measurements of the chlorophyll‐normalized number of reaction centers (nRCII), resulting in a mean summer Φe:C which was ∼ 3 times lower than the mean winter Φe:C. Empirical relationships were established between Φe:C, light and NPQ, however they were not consistent across locations or seasons. The seasonal decoupling of Φe:C is the result of differences in Ek‐dependent and Ek‐independent variability, which require new modelling approaches and improvements to bio‐optical techniques to account for these inter‐seasonal differences in both taxonomy and environmental mean conditions.

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Bio-optical modelling of primary production in the SW Finnish coastal zone, Baltic Sea: fast repetition rate fluorometry in Case 2 waters

Cited by 47 publications

References 67 publications

Photosynthetic electron turnover in the tropical and subtropical Atlantic Ocean

Photosynthetic electron turnover in the tropical and subtropical Atlantic Ocean

Primary productivity and the coupling of photosynthetic electron transport and carbon fixation in the Arctic Ocean

Seasonal regulation of the coupling between photosynthetic electron transport and carbon fixation in the Southern Ocean

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