Identification of senescence and death in <i>Emiliania huxleyi</i> and <i>Thalassiosira pseudonana</i>: Cell staining, chlorophyll alterations, and dimethylsulfoniopropionate (DMSP) metabolism

Franklin, Daniel J.; Airs, Ruth L.; Fernandes, Michelle; Bell, Thomas G.; Bongaerts, Roy J.; Berges, John A.; Malin, Gill

doi:10.4319/lo.2012.57.1.0305

Cited by 47 publications

(72 citation statements)

References 55 publications

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“…In the upper mixed layer of open oligotrophic oceans, phytoplankton can experience high (dynamic) irradiance conditions in combination with low nutrient availability. It has been suggested that these co-occurring conditions increase photoinhibition and viability loss in natural communities (Lesser et al 1994;Llabrés and Agustí 2006;Franklin et al 2009). However, the present study showed that P. marinus, Ostreococcus sp., and T. oceanica are actually less susceptible to both photoinhibition and viability loss during high-irradiance exposure when nutrient availability is low.…”

Section: Discussionmentioning

confidence: 99%

“…In addition to the direct effect of low-nutrient availability on phytoplankton viability, it may have considerable effects on phytoplankton photophysiology and consequently on the response to high-irradiance intensities. Generally, the lightharvesting capacity is reduced during nutrient starvation by a reduction in the cellular chlorophyll a (Chl a) concentration and quantum yield of PSII, as well as an increase in the relative amount of carotenoids Berges and Falkowski 1998;Franklin et al 2012). However, the absorption of chlorophyll and the absorption cross section of the remaining PSII may increase during nutrient starvation Berges et al 1996), partially counteracting the reduced light-harvesting capacity.…”

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confidence: 99%

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Low nutrient availability reduces high‐irradiance‐induced viability loss in oceanic phytoplankton

Kulk¹,

Poll²,

Visser³

et al. 2013

Limnology & Oceanography

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In situ viability of oceanic phytoplankton may be relatively low in open oceans. This is assumed to be related to the high-irradiance and low-nutrient conditions typical for oligotrophic regions. However, experimental evidence for this phenomenon was not yet available. In the present study, the importance of nutrient availability in highirradiance-induced viability loss was therefore studied for three key oceanic phytoplankton species. Prochlorococcus marinus, Ostreococcus sp., and Thalassiosira oceanica were acclimated to two different N : P ratios. Growth, viability, and photophysiology were assessed under nutrient-replete and N-and P-starved conditions. Simultaneously, high-irradiance-induced photoinhibition and viability loss were measured and three inhibitors were used to investigate the underlying physiological mechanisms contributing to viability loss. Highirradiance exposure caused viability loss in P. marinus and Ostreococcus sp., but not in T. oceanica. Low-nutrient availability enhanced survival during high-irradiance exposure, although species-specific differences were observed. The lower sensitivity to high-irradiance intensities at low-nutrient availability was related to conformational changes in photosystem II in P. marinus, to enhanced photoprotection by the xanthophyll pigment cycle and alternative electron transport in Ostreococcus sp., and to enhanced photoprotection by the xanthophyll pigment cycle in T. oceanica. Climate change may lead to enhanced stratification in the open ocean. The resulting increase in the average irradiance intensity phytoplankton experience may promote viability loss in the smallest phytoplankton size fraction. However, this effect may partially be counteracted by the simultaneously expected decrease in nutrient availability.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Low nutrient availability reduces high‐irradiance‐induced viability loss in oceanic phytoplankton

Kulk¹,

Poll²,

Visser³

et al. 2013

Limnology & Oceanography

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“…Veldhuis et al (2001) hypothesized that 'automortality' is a significant source of DOM leakage, particularly as cells with compromised cell membranes are often still capable of photosynthesis. Subsequent work has shown that stresses such as low irradiance or nutrient limitation affect compromised plasma membranes and autocatalytic cell death in phytoplankton (Berman-Frank et al, 2007;Timmermans et al, 2007;Franklin et al, 2012).…”

Section: Autocatalytic Cell Deathmentioning

confidence: 99%

“…Recent research has shown that phytoplankton also undergo the physiological process of autocatalytic cell-suicide, which can lead to lysis of the cells; this process is analogous to programmed cell death (PCD) in metazoans (Bidle & Falkowski, 2004;Franklin et al, 2006). Autocatalytic cell death is a process that is indicated by multiple changes within the phytoplankton cell and it is often difficult to characterize such cells as clearly dead or alive (Franklin et al, 2006(Franklin et al, , 2012. Cell membrane integrity is used as an early indicator of cell death (Veldhuis et al, 2001).…”

Section: Autocatalytic Cell Deathmentioning

confidence: 99%

Dissolved organic matter (DOM) release by phytoplankton in the contemporary and future ocean

Thornton

2014

European Journal of Phycology

368

311

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The partitioning of organic matter (OM) between dissolved and particulate phases is an important factor in determining the fate of organic carbon in the ocean. Dissolved organic matter (DOM) release by phytoplankton is a ubiquitous process, resulting in 2-50% of the carbon fixed by photosynthesis leaving the cell. This loss can be divided into two components: passive leakage by diffusion across the cell membrane and the active exudation of DOM into the surrounding environment. At present there is no method to distinguish whether DOM is released via leakage or exudation. Most explanations for exudation remain hypothetical; as while DOM release has been measured extensively, there has been relatively little work to determine why DOM is released. Further research is needed to determine the composition of the DOM released by phytoplankton and to link composition to phytoplankton physiological status and environmental conditions. For example, the causes and physiology of phytoplankton cell death are poorly understood, though cell death increases membrane permeability and presumably DOM release. Recent work has shown that phytoplankton interactions with bacteria are important in determining both the amount and composition of the DOM released. In response to increasing CO 2 in the atmosphere, climate change is creating increasingly stressful conditions for phytoplankton in the surface ocean, including relatively warm water, low pH, low nutrient supply and high light. As ocean physics and chemistry change, it is hypothesized that a greater proportion of primary production will be released directly by phytoplankton into the water as DOM. Changes in the partitioning of primary production between the dissolved and particulate phases will have bottom-up effects on ecosystem structure and function. There is a need for research to determine how these changes affect the fate of organic matter in the ocean, particularly the efficiency of the biological carbon pump.

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“…In previous studies, two types of cyanobacteria have been proposed in terms of pigment and morphological patterns (Jeffrey and Wright, 2006 thiebautii possessed significant amounts of these carotenoids. In the Synechococcus strain, Chl a allomer (i.e., Chl a allo; peak 32) was detected, indicating the oxidation of Chl a by cell senescence (Franklin et al, 2012).…”

Section: Separation and Identification Of Pigments In Phytoplankton Cmentioning

confidence: 99%

Rapid and highly sensitive analysis of chlorophylls and carotenoids from marine phytoplankton using ultra-high performance liquid chromatography (UHPLC) with the first derivative spectrum chromatogram (FDSC) technique

2015

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We developed a rapid and highly sensitive analytical method for chlorophylls and carotenoids derived from marine phytoplankton using ultra-high performance liquid chromatography (UHPLC).High-performance liquid chromatography (HPLC) has been widely used in phytoplankton pigment analysis since the 1980's for estimating the abundance, composition, and photosynthetic physiology of natural algal assemblages or laboratory cultures. However, the run-time of the HPLC analyses is generally ca. 30 min or more, which is time-consuming for analysts. Our UHPLC technique enabled us to complete the separations of chlorophylls and carotenoids from marine phytoplankton within 7 min with similar resolution as conventional HPLC methods. The analytical method was tested on authentic pigment standards, marine phytoplankton cultures, and field samples that were collected from the central tropical and subarctic Pacific plus the neritic Bering Sea. Critical pigment pairs that generally co-eluted as a single peak were successively resolved by obtaining the first derivative spectrum chromatograms (FDSCs) with a photodiode array (PDA) detector based on differences in pigment absorption spectra, e.g., chlorophyll (Chl) c 2 and Mg 2,4 divinyl (DV) pheoporphyrin a 5 monomethyl ester (MgDVP), as well as DVChl b and Chl b. Because the maximum injection volume of UHPLC is generally lower than that of HPLC to minimize the unwanted broadening of chromatographic peaks, the detection sensitivity needed to be increased, especially for oligotrophic seawater samples with low pigment concentration. To overcome this sensitivity issue, a PDA detector equipped with an 85 mm path length capillary cell was used with a fluorescence detector.As a result, the limit of quantitation (LOQ) as determined by absorbance was of the order of 0.1 ng for chlorophylls and carotenoids. Furthermore, a bead-beating technique using 3 N,N-dimethylformamide (DMF) and zirconia beads was used to minimize the volume of the organic solvent utilized for pigment extraction. Our UHPLC method can replace the conventional HPLC techniques, and allows us to yield high-throughput data of the chlorophylls and carotenoids derived from marine phytoplankton.4

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Identification of senescence and death in Emiliania huxleyi and Thalassiosira pseudonana: Cell staining, chlorophyll alterations, and dimethylsulfoniopropionate (DMSP) metabolism

Cited by 47 publications

References 55 publications

Low nutrient availability reduces high‐irradiance‐induced viability loss in oceanic phytoplankton

Low nutrient availability reduces high‐irradiance‐induced viability loss in oceanic phytoplankton

Dissolved organic matter (DOM) release by phytoplankton in the contemporary and future ocean

Rapid and highly sensitive analysis of chlorophylls and carotenoids from marine phytoplankton using ultra-high performance liquid chromatography (UHPLC) with the first derivative spectrum chromatogram (FDSC) technique

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