Responses of microphytobenthos to light: primary production and carbohydrate allocation over an emersion period

Perkins, Rupert; Underwood, Graham J. C.; Brotas, Vanda; Snow, Gavin C.; Jesus, Bruno; Ribeiro, Lourenço

doi:10.3354/meps223101

Cited by 160 publications

(152 citation statements)

References 34 publications

(48 reference statements)

Supporting

Mentioning

145

Contrasting

Unclassified

Order By: Relevance

“…Together, these patterns indicate that photochemistry could not be continuing to increase as suggested by the rapid light response curve data, and also that downregulation had reached a maximum level that could not account for further dissipation of energy above 1200 mmol m À 2 s À 1 PAR. This pattern of events is not unprecedented, being paralleled by observations on benthic microalgal biofilms in estuaries (Perkins et al, 2001(Perkins et al, , 2010a where the inflexion point corresponded to the initiation of downward cell migration into the light attenuating sediments, thus reducing the light level to which the cells were exposed, and resulting in a falsely high rETR at higher light levels.…”

Section: Photophysiology Of Ice Algaementioning

confidence: 88%

Photophysiology and albedo-changing potential of the ice algal community on the surface of the Greenland ice sheet

et al. 2012

View full text Add to dashboard Cite

Darkening of parts of the Greenland ice sheet surface during the summer months leads to reduced albedo and increased melting. Here we show that heavily pigmented, actively photosynthesising microalgae and cyanobacteria are present on the bare ice. We demonstrate the widespread abundance of green algae in the Zygnematophyceae on the ice sheet surface in Southwest Greenland. Photophysiological measurements (variable chlorophyll fluorescence) indicate that the ice algae likely use screening mechanisms to downregulate photosynthesis when exposed to high intensities of visible and ultraviolet radiation, rather than non-photochemical quenching or cell movement. Using imaging microspectrophotometry, we demonstrate that intact cells and filaments absorb light with characteristic spectral profiles across ultraviolet and visible wavelengths, whereas inorganic dust particles typical for these areas display little absorption. Our results indicate that the phototrophic community growing directly on the bare ice, through their photophysiology, most likely have an important role in changing albedo, and subsequently may impact melt rates on the ice sheet.

show abstract

Section: Photophysiology Of Ice Algaementioning

confidence: 88%

Photophysiology and albedo-changing potential of the ice algal community on the surface of the Greenland ice sheet

et al. 2012

View full text Add to dashboard Cite

show abstract

“…Yet, despite high irradiance levels at the sediment surface, photoinhibition is seldom recorded, which suggests that behavioural and photophysiological strategies have evolved that prevent photodamage in microphytobenthos (Kingston, 1999b;Perkins et al, 2001;Blanchard et al, 2004;Consalvey et al, 2004a, b). Although the importance of the xanthophyll pigments in photoprotection has been recognized, very few studies have examined xanthophyll cycling in microphytobenthic communities.…”

Section: Discussionmentioning

confidence: 99%

“…In microphytobenthos, photoinhibition can be prevented in several ways. The most notable of these is migration of the cells: many of the commonest benthic diatoms possess a gliding motility which allows movement away from the sediment surface when light or UV levels become too high, or when cells have been exposed for a prolonged period (Perkins et al, 2001;Consalvey et al, 2004a).…”

Section: Introductionmentioning

confidence: 99%

“…Accurate pigment data on microphytobenthic photoacclimation are still scarce and photosynthetic responses have been studied mainly by variable fluorescence analyses (e.g. Kromkamp et al, 1998;Perkins et al, 2001). Serodio et al (2005) were the first to measure the xanthophyll pigments and to link the presence of diatoxanthin to non-photochemical quenching signals.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Photoacclimation in microphytobenthos and the role of xanthophyll pigments

Leeuwe¹,

Brotas

Consalvey

et al. 2008

European Journal of Phycology

View full text Add to dashboard Cite

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.

show abstract

“…In addition, while the 'overflow' hypothesis is often proposed (Underwood and Paterson, 2003;Stal, 2009), it was never clearly proven. A few studies have shown a positive relationship between light intensity and EPS production (Underwood, 2002;Wolfstein and Stal, 2002) but other studies have reported a negative relation with light intensity and no relationship with nutrient limitation (Perkins et al, 2001;Hanlon et al, 2006). To date there is no information on EPS production in different benthic diatom growth forms, and only EPL species have been compared (Underwood and Paterson, 2003), showing no clear relationship between light response and EPS secretion.…”

Section: Photoprotection In Intertidal Benthic Diatomsmentioning

confidence: 99%

Growth form defines physiological photoprotective capacity in intertidal benthic diatoms

et al. 2014

View full text Add to dashboard Cite

In intertidal marine sediments, characterized by rapidly fluctuating and often extreme light conditions, primary production is frequently dominated by diatoms. We performed a comparative analysis of photophysiological traits in 15 marine benthic diatom species belonging to the four major morphological growth forms (epipelon (EPL), motile epipsammon (EPM-M) and non-motile epipsammon (EPM-NM) and tychoplankton (TYCHO)) found in these sediments. Our analyses revealed a clear relationship between growth form and photoprotective capacity, and identified fast regulatory physiological photoprotective traits (that is, non-photochemical quenching (NPQ) and the xanthophyll cycle (XC)) as key traits defining the functional light response of these diatoms. EPM-NM and motile EPL showed the highest and lowest NPQ, respectively, with EPM-M showing intermediate values. Like EPL, TYCHO had low NPQ, irrespective of whether they were grown in benthic or planktonic conditions, reflecting an adaptation to a low light environment. Our results thus provide the first experimental evidence for the existence of a trade-off between behavioural (motility) and physiological photoprotective mechanisms (NPQ and the XC) in the four major intertidal benthic diatoms growth forms using unialgal cultures. Remarkably, although motility is restricted to the raphid pennate diatom clade, raphid pennate species, which have adopted a non-motile epipsammic or a tychoplanktonic life style, display the physiological photoprotective response typical of these growth forms. This observation underscores the importance of growth form and not phylogenetic relatedness as the prime determinant shaping the physiological photoprotective capacity of benthic diatoms.

show abstract

Responses of microphytobenthos to light: primary production and carbohydrate allocation over an emersion period

Cited by 160 publications

References 34 publications

Photophysiology and albedo-changing potential of the ice algal community on the surface of the Greenland ice sheet

Photophysiology and albedo-changing potential of the ice algal community on the surface of the Greenland ice sheet

Photoacclimation in microphytobenthos and the role of xanthophyll pigments

Growth form defines physiological photoprotective capacity in intertidal benthic diatoms

Contact Info

Product

Resources

About