A mechanistic model of photoinhibition

Marshall, Helen; Geider, Richard J.; Flynn, Kevin J.

doi:10.1046/j.1469-8137.2000.00575.x

Cited by 96 publications

(66 citation statements)

References 65 publications

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“…Our results show a lack of relationship between Fe concentration in the tissue of macroalgae and the associated ETRmax, which could indicate a generalized iron limitation for the growth of macroalgae in the main body of the Rea Sea. Nonetheless, ETRmax provides a measure of the capacity of the photosystems to utilize the absorbed light energy (Marshall et al, 2000) but this does not necessarily translate into plant growth (e.g., Seboek et al, 2017), and further experimental investigation manipulating Fe inputs while assessing gross primary production is necessary.…”

Section: Discussionmentioning

confidence: 99%

Iron Deficiency in Seagrasses and Macroalgae in the Red Sea Is Unrelated to Latitude and Physiological Performance

et al. 2018

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Iron can limit primary production in shallow marine systems, especially in tropical waters characterized by carbonated sediments, where iron is largely trapped in a non-available form. The Red Sea, an oligotrophic ecosystem characterized by a strong N-S latitudinal nutrient gradient, is a suitable setting to explore patterns in situ of iron limitation in macrophytes and their physiological performance under different iron regimes. We assessed the interactions between environmental gradients and physiological parameters of poorly-studied Red Sea macrophytes. Iron concentration, chlorophyll a concentration, blade thickness, and productivity of 17 species of macrophytes, including seven species of seagrasses and 10 species of macroalgae, were measured at 21 locations, spanning 10 latitude degrees, along the Saudi Arabian coast. Almost 90% of macrophyte species had iron concentrations below the levels indicative of iron sufficiency and more than 40% had critically low iron concentrations, suggesting that iron is a limiting factor of primary production throughout the Red Sea. We did not identify relationships between tissue iron concentration, chlorophyll a concentration and physiological performance of the 17 species of seagrass and macroalgae. There was also no latitudinal pattern in any of the parameters studied, indicating that the South to North oligotrophication of the Red Sea is not reflected in iron concentration, chlorophyll a concentration or productivity of Red Sea macrophytes.

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Section: Discussionmentioning

confidence: 99%

Iron Deficiency in Seagrasses and Macroalgae in the Red Sea Is Unrelated to Latitude and Physiological Performance

et al. 2018

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“…The impact of photodamage suffered during periods of high irradiance is time-dependent (Han et al 2000, Marshall et al 2000. When exposure to high irradiance is only brief, little damage will be suffered and repair processes require relatively few costs.…”

Section: Discussionmentioning

confidence: 99%

Taxon-specific differences in photoacclimation to fluctuating irradiance in an Antarctic diatom and a green flagellate

Leeuwe¹,

Sikkelerus²,

Gieskes³

et al. 2005

Mar. Ecol. Prog. Ser.

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Photoacclimation towards rapid changes in irradiance was studied in 2 Antarctic microalgae, the diatom Chaetoceros brevis (Bacillariophyceae) and the flagellate Pyramimonas sp. (Prasinophyceae). Both species were subjected to 3 different light regimes. Two regimes of vertical mixing (1:1 h and 3:3 h high light:low light) were superimposed on a diurnal light cycle mimicking the solar sine. For both species, maximum growth was recorded at the fastest rates of light fluctuation (1:1 h). The light regimes had a minor effect on growth rates of the flagellate but growth in the diatom was reduced significantly at moderate rates of mixing (3:3 h). While xanthophyll cycling was active in both species, fluorescence analysis with a dual-modulated fluorometer showed that down-regulation of photosynthetic efficiency was more pronounced in Pyramimonas sp. (ca. 50%) than in C. brevis (ca. 30%). The ratio of photoprotectors to chlorophyll a was not significantly affected by the light regime, neither in the flagellate nor in the diatom. In the flagellate, state transition offered an additional means of energy dissipation during the periods of high irradiance. The diatom apparently acclimated to the average light intensity received and not to the maximum irradiance. It can be reasoned that this strategy led to photodamage during the 3:3 h cycling. It is argued that enhanced maintenance costs associated with necessary repair processes can explain the reduced growth rate that was observed. The ecological consequences for large bloom-forming diatom species are briefly discussed.

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“…leeuwe@rug.nl than can be used in the cell. Prolonged input of excess energy may induce radical formation in the photosystems, which can ultimately lead to irreversible damage at several places in the cell (Marshall et al, 2000). In microphytobenthos, photoinhibition can be prevented in several ways.…”

Section: Introductionmentioning

confidence: 99%

Photoacclimation in microphytobenthos and the role of xanthophyll pigments

Leeuwe¹,

Brotas

Consalvey

et al. 2008

European Journal of Phycology

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Estuarine microphytobenthos are frequently exposed to excessively high irradiances. Photoinhibition in microalgae is prevented by various photophysiological responses. We describe here the role of the xanthophyll pigments in photoacclimation. The pigment composition of the microphytobenthos was studied in three European estuaries (Barrow, Ireland; Eden, UK; Tagus, Portugal). Using HPLC-analyses, microscale changes in biomass and pigment composition were monitored over short (hourly) and long (seasonal) time scales. In the Barrow estuary, the biomass of microphytobenthos (measured as chlorophyll a) increased significantly in the top 400-500 mm of the sediment surface within 1 h of emersion; simultaneously, the xanthophyll pool size (diadinoxanthin plus diatoxanthin, dd þ dt) almost doubled. A more gradual conversion of dd into dt was observed, with the dt:dd ratio increasing from <0.1 at the start of emersion to >0.3 after 3 h emersion. Similar trends in the dt:dd ratio were observed in the surface sediments of the Eden and the Tagus estuaries. Higher ratios were recorded in the Tagus estuary, which may be explained by higher incident irradiance. In addition, seasonal studies carried out in the Eden and Tagus estuaries showed that the xanthophyll pool size increased by 10% in the summer months. The pool size was highest in the Tagus estuary. Concurrently, high values for the de-epoxidation state were recorded, with values for dt/(dt þ dd) > 0.35 recorded in the summer. At the Eden, the ratio never exceeded 0.3. The de-epoxidation state was higher in winter than in summer, which was ascribed to the low winter temperatures. During a vertical migration study, a negative relationship between chlorophyll a and the de-epoxidation state was observed. It is suggested that this relationship originates from 'micro-migration' within the biofilm. Migration within the euphotic zone may provide an alternative means for cells to escape photodamage. In this paper, we propose that both xanthophyll cycling and 'micro'-migration play an important role in photoacclimation and it appears that these processes operate in parallel to regulate the photosynthetic response.

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A mechanistic model of photoinhibition

Cited by 96 publications

References 65 publications

Iron Deficiency in Seagrasses and Macroalgae in the Red Sea Is Unrelated to Latitude and Physiological Performance

Iron Deficiency in Seagrasses and Macroalgae in the Red Sea Is Unrelated to Latitude and Physiological Performance

Taxon-specific differences in photoacclimation to fluctuating irradiance in an Antarctic diatom and a green flagellate

Photoacclimation in microphytobenthos and the role of xanthophyll pigments

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