Individual and interactive effects of warming and CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; on &amp;lt;i&amp;gt;Pseudo-nitzschia subcurvata&amp;lt;/i&amp;gt; and &amp;lt;i&amp;gt;Phaeocystis antarctica&amp;lt;/i&amp;gt;, two dominant phytoplankton from the Ross Sea, Antarctica

Zhu, Zhi; Qu, Pingping; Gale, Jasmine; Fu, Fei-Xue; Hutchins, David A.

doi:10.5194/bg-14-5281-2017

Cited by 29 publications

(21 citation statements)

References 67 publications

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“…We observed a 20% lower growth rate for both low iron treatments compared to the +Fe treatments ( Table 3). In a previous temperature experiment with P. subcurvata the growth rate at 2 • C was 0.6 d −1 under ample supply of iron (Zhu et al, 2017) and thus similar to our +Fe treatments. In agreement with our results, another experiment by Zhu et al (2016), reported a 20% difference in growth rate of P. subcurvata at 0 • C between low and high iron conditions.…”

Section: Effects Of the Experimental Conditions On Growth Size And supporting

confidence: 87%

Dissolved Domoic Acid Does Not Improve Growth Rates and Iron Content in Iron-Stressed Pseudo-Nitzschia subcurvata

et al. 2020

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Many regions of Antarctica are classified as high nutrient low chlorophyll (HNLC) areas. In these, iron availability is limiting primary productivity and subsequent carbon export. Domoic acid (DA) has previously been detected in the Southern Ocean and suggested to act as a ligand that facilitates iron assimilation for Pseudo-nitzschia spp., species that contribute to Antarctic diatom blooms. An incubation experiment using the Antarctic species Pseudo-nitzschia subcurvata was performed in Antarctic seawater at low and high iron concentrations. Dissolved DA was added to one set of each of the two treatments. This was done to verify whether DA positively affects the growth of the non-toxic species Pseudo-nitzschia subcurvata and increases its cellular iron content, particularly under low iron conditions. We hypothesize that (i) DA is taken up under low iron conditions (ii) that more iron is taken up if DA is available and (iii) that the growth rate increases in the presence of DA. We showed that P. subcurvata did not take up any added DA, even under low iron conditions. Additionally and contrary to our hypothesis, the cells were not positively influenced by the addition of dissolved DA in terms of growth rate, cellular iron and carbon content. Hence, there was no significant difference in iron content between the different treatments. However, the cellular copper content increased under low iron conditions when DA was added. This study suggests that dissolved DA in naturally occurring concentrations does not increase bioavailability of iron to P. subcurvata and that only species producing DA might benefit from it.

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Section: Effects Of the Experimental Conditions On Growth Size And supporting

confidence: 87%

Dissolved Domoic Acid Does Not Improve Growth Rates and Iron Content in Iron-Stressed Pseudo-Nitzschia subcurvata

et al. 2020

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“…Phytoplankton are able to efficiently grow over a range of temperatures around the optimal growth temperature but their growth at substantially different temperatures can lead to photodamage (Huner et al, 2008), inhibition of protein synthesis (Li et al, 2019), or the decline in photosynthetic efficiency (Falk et al, 2006). As a result, a growth curve of phytoplankton is unimodal (Boyd et al, 2013;Zhu et al, 2017) with increasing growth rate from the minimum temperature to the optimum temperature and decreasing growth rate towards the maximum temperature (Madigan et al, 2017).…”

Section: Temperaturementioning

confidence: 99%

“…Although the underling mechanism for explaining lower P:C at higher temperature is not fully understood, there are three hypotheses (Paul et al, 2015): (1) increase in metabolic stimulation of inorganic carbon uptake over phosphorus uptake; (2) increase in nutrient use efficiency which enables greater carbon fixation for given nutrient availability; and (3) "translation compensation theory," which predicts that less P-rich ribosomes are required for protein synthesis and growth as the translation process becomes kinetically more efficient (McKew et al, 2015;Toseland et al, 2013;Woods et al, 2003;Xu et al, 2014;Zhu et al, 2017). In this meta-analysis, the decrease in P:C in cyanobacteria at elevated temperatures (Fig.…”

Section: Temperaturementioning

confidence: 99%

A meta-analysis on environmental drivers of marine phytoplankton C : N : P

Tanioka¹,

Matsumoto²

2019

Preprint

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Abstract. The elemental stoichiometry of marine phytoplankton plays a critical role in the global carbon cycle through carbon export. Although extensive laboratory experiments have been carried out over the years to assess the influence of different environmental drivers on the elemental composition of phytoplankton, a comprehensive quantitative assessment of the processes is still lacking. Here, we synthesized the responses of P : C and N : C ratios of marine phytoplankton to five major drivers (phosphate and nitrate, irradiance, temperature, and iron) by meta-analysis of laboratory experimental data available in the literature. Our results show that the response of the ratios to changes in macronutrients is consistent across all the studies, where the nutrient availability is positively related to changes in P : C and N : C ratios. We found that diatoms are more sensitive to the changes in macronutrients compared to other eukaryotes and cyanobacteria, possibly due to their larger cell size and their abilities to quickly regulate their gene expression patterns required for nutrient uptake. The effect of irradiance on P : C was mixed and not significant, but the same effect on N : C was significant and constant across all studies where an increase in irradiance decreased N : C. The response to temperature changes was mixed by species, except warming consistently decreased P : C ratio in cyanobacteria. This may explain why P : C is consistently low in the cyanobacteria-dominated subtropical oceans. The effect of iron on P : C and N : C for cyanobacteria were statistically significant but the small sample size precludes drawing firm conclusions. Overall, our findings highlight the high stoichiometric plasticity of diatoms and the importance of macronutrients in determining P : C and N : C ratios, which both provide us insights on how to understand and model plankton diversity and productivity.

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“…The effect of temperature on model diatom species has been well documented (Sunda and Huntsman, 2011); however, the interaction between temperature, light, and Fe on phytoplankton growth rate has only recently been explored in Southern Ocean species (Zhu et al, 2017;Boyd, 2019). Studies of subantarctic phytoplankton have identified Fe and temperature as key controls on phytoplankton growth with light, macronutrients and CO 2 playing a lesser role (Boyd et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

“…The growth rate of phytoplankton generally increases with temperature, until an optimum temperature is reached (Eppley, 1972). Once this temperature optimum has been exceeded, growth rate decreases and eventual mortality occurs (Kudo et al, 2000;Boyd et al, 2013;Zhu et al, 2017). Unlike tropical phytoplankton, which are already at or near at their thermal capacity, cold-adapted phytoplankton display optimum growth temperatures higher than the temperature of their current environment (Thomas et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Iron Availability Influences the Tolerance of Southern Ocean Phytoplankton to Warming and Elevated Irradiance

et al. 2019

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The Southern Ocean is responsible for approximately 40% of oceanic carbon uptake through biological and physical processes. In the Southern Ocean, phytoplankton growth is limited by low iron (Fe) and light supply. Climate model projections for the Southern Ocean indicate that temperature, underwater irradiance and Fe supply are likely to change simultaneously in the future due to increasing anthropogenic carbon dioxide emissions. The individual effects of these environmental properties on phytoplankton physiology have been extensively researched, and culturing studies using Southern Ocean phytoplankton have shown that temperature and Fe will play a key role on setting growth under future conditions. To explore the potential responses of Southern Ocean phytoplankton to these environmental changes, we cultured the haptophyte Phaeocystis antarctica and the diatoms Chaetoceros flexuosus, Proboscia inermis, and Thalassiosira antarctica under two light and iron combinations and over a range of temperatures. Our study revealed that the thermal response curves of key Southern Ocean phytoplankton are diverse, with the highest growth rates measured at 5 • C (the annual temperature range at the isolation sites is currently 1-4 • C). Warming had species-specific effects on the photochemical efficiency of photosystem II (PSII; F v /F m), the functional absorption cross-section of PSII (σ PSII), carbon:nitrogen ratio and cellular Chlorophyll a concentrations. Iron availability increased species' ability to tolerate warmer conditions by increasing the upper limit for growth and subsequently increasing the thermal niche that each species inhabit.

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Individual and interactive effects of warming and CO<sub>2</sub> on <i>Pseudo-nitzschia subcurvata</i> and <i>Phaeocystis antarctica</i>, two dominant phytoplankton from the Ross Sea, Antarctica

Cited by 29 publications

References 67 publications

Dissolved Domoic Acid Does Not Improve Growth Rates and Iron Content in Iron-Stressed Pseudo-Nitzschia subcurvata

Dissolved Domoic Acid Does Not Improve Growth Rates and Iron Content in Iron-Stressed Pseudo-Nitzschia subcurvata

A meta-analysis on environmental drivers of marine phytoplankton C : N : P

Iron Availability Influences the Tolerance of Southern Ocean Phytoplankton to Warming and Elevated Irradiance

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