Excessive irradiance and antioxidant responses of an Antarctic marine diatom exposed to iron limitation and to dynamic irradiance

Poll, Willem H. van de; Janknegt, Paul J.; Leeuwe, Maria A. van; Visser, Ronald J. W.; Buma, Anita G. J.

doi:10.1016/j.jphotobiol.2008.09.003

Cited by 30 publications

(30 citation statements)

References 24 publications

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“…The lower concentrations of chlorophyll and most light-harvesting xanthophylls furthermore indicated that the Fe-limited cells suffered a lower light-harvesting capacity. Fe is essential for all life and earlier studies showed that Fe-deficiency can lead to anemia in mammals, the dysfunction of Fe-dependent enzymes in yeast, the reduction of the amount of electron-transferring complexes and induction of chlorosis in plants, and a decrease in Fe-intensive light harvesting pigment synthesis and increased photoprotective pigments in phytoplankton (Geider et al, 1993;Mengel, 1994;van Leeuwe and Stefels, 2007;van de Poll et al, 2009;Zhang, 2014). In line with the fact that the Fe concentrations in the Fe-limited cultures were always below the limit of detection, these results confirm that both phytoplankton cultures were indeed Fe-limited, despite that M. pusilla showed healthy F v /F m .…”

Section: Steady Statementioning

confidence: 99%

Phytoplankton Virus Production Negatively Affected by Iron Limitation

2016

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Fe-limited monocultures of the ubiquitous algae Micromonas pusilla and Phaeocystis globosa were infected with their respective viruses (MpV and PgV) to ascertain the effect of Fe-limitation on phytoplankton host-virus dynamics. The effect of the viral shunt on Fe concentrations and bioavailability is starting to gain attention, since not only is Fe released through lysis, but also its solubility is increased by the simultaneous release of Fe-binding dissolved organic ligands. However, the effect of Fe-limitation on the process of viral lysis itself is poorly understood. In this study fine adjustment of a seawater-based culture medium including the use of ultra-clean trace metal conditions and protocols allowed for Fe-limited growth at nanomolar amounts as opposed to micromolar amounts typically employed in culturing. Viral lysates derived from Fe-limited and Fe-replete (for comparison) hosts were cross-inoculated in hosts of both Fe treatments, to judge the quality of the resulting lysate as well as the effect of Fe introduction after initial infection. For both phytoplankton host-virus systems, the virus burst size reduced strongly under Fe stress, i.e., on average 28 ± 1% of replete. Moreover, the MpV virus progeny showed highly reduced infectivity of 30 ± 7%, whereas PgV infectivity was not affected. A small addition of Fe to Fe-limited cultures coming from the Fe-replete lysate counteracted the negative effect of Fe-limitation on phytoplankton virus production to some extent (but still half of replete), implying that the physiological history of the host at the moment of infection was an important underlying factor. These results indicate that Fe-limitation has the strong potential to reduce the loss of phytoplankton due to virus infection, thereby affecting the extent of Fe-cycling through the viral shunt. To what extent this affects the contribution of viral lysis-induced organic ligand release needs further study.

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Section: Steady Statementioning

confidence: 99%

Phytoplankton Virus Production Negatively Affected by Iron Limitation

2016

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“…Fe ions would become more available from binding ligands produced through UV-mediated cell lysis (Barbeau et al 2001a,b), through the hydrogen peroxide produced due to the interactions between organic matter from cell lysis and UVR is toxic to some phytoplankton species, and this could have substantial effects on phytoplankton communities (Leunert et al 2014). Van de Poll et al (2005) reported that Fe-limited cultures of the Antarctic marine diatom Chaetoceros brevis were less sensitive to high levels of PAR and UVR than Fe-replete cultures, this possibly being associated with elevated levels of ROS scavengers, such as superoxide dismutase and ascorbate peroxidase, in Fe-limited cells (Van de Poll et al 2009). Clearly more work is required in this area.…”

Section: Nutrient−uvb Interactionsmentioning

confidence: 99%

Interactive effects of nutrient supply and other environmental factors on the sensitivity of marine primary producers to ultraviolet radiation: implications for the impacts of global change

Beardall¹,

Stojkovic²,

Gao

2014

Aquat. Biol.

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Understanding the effects of global climate change on the algae that form the basis of most aquatic food chains is of paramount importance in our ability to make informed decisions about the future of production systems, marine ecosystems, and the global carbon cycle. Despite the Montreal Protocol to restrict the release of harmful chlorofluorocarbons into the atmosphere, ozone levels have not recovered at all latitudes, and in some regions levels of UVB are still rising due to interactions with phenomena related to climate change. However, the effects of UV radiation may be modulated by other environmental changes. In this review, we discuss how factors such as elevated CO 2 and ocean acidification, increasing temperature, and reduced nutrient supply associated with enhanced stratification can interact with UV radiation to affect algal physiological performance and growth. For instance, nutrient limitation enhances UV-induced inhibition due to the reduced capacity of algae to screen out UVB and/or impairment of their capacity to repair damage. Higher temperatures tend to promote repair more than photochemical damage so result in a net reduction of UV inhibition. Elevated CO 2 and ocean acidification has complex interactions with UV radiation, with mixed net outcomes for algal productivity. Differential effects of UVA and UVB have been shown to depend on their irradiance levels; while moderate levels of UVA stimulate growth and photosynthesis of some algae, UVB almost always results in harm to marine primary producers.

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“…In contrast, almost nothing is known about the interactive impacts of UVR and Fe-limitation on CCMs and CO 2 fixation. Van de Poll et al (2005) indicated that iron-limited cultures of the Antarctic marine diatom Chaetoceros brevis were less sensitive to high levels of PAR and UVR than were iron-replete cultures, an effect possibly due to elevated superoxide dismutase and ascorbate peroxidase (scavengers of reactive oxygen species) in iron-limited cells (Van de Poll et al 2009). It may be of interest here that induction of CCMs in Chlamydomonas (Im et al 2003) and Cyanophora (Burey et al 2005) is paralleled by increased expression of genes related to removal of reactive oxygen species.…”

Section: Uvbmentioning

confidence: 99%

Algal and aquatic plant carbon concentrating mechanisms in relation to environmental change

et al. 2011

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Abstract.Carbon dioxide concentrating mechanisms (also known as inorganic carbon concentrating mechanisms; both abbreviated as CCMs) presumably evolved under conditions of low CO 2 availability. However, the timing of their origin is unclear since there are no sound estimates from molecular clocks, and even if there were, there are no proxies for the functioning of CCMs. Accordingly, we cannot use previous episodes of high CO 2 (e.g. the Palaeocene-Eocene Thermal Maximum) to indicate how organisms with CCMs responded. Present and predicted environmental change in terms of increased CO 2 and temperature are leading to increased CO 2 and HCO 3 -and decreased CO 3 2-and pH in surface seawater, as well as decreasing the depth of the upper mixed layer and increasing the degree of isolation of this layer with respect to nutrient flux from deeper waters. The outcome of these forcing factors is to increase the availability of inorganic carbon, photosynthetic active radiation (PAR) and ultraviolet B radiation (UVB) to aquatic photolithotrophs and to decrease the supply of the nutrients (combined) nitrogen and phosphorus and of any non-aeolian iron. The influence of these variations on CCM expression has been examined to varying degrees as acclimation by extant organisms. Increased PAR increases CCM expression in terms of CO 2 affinity, while increased UVB has a range of effects in the organisms examined; little relevant information is available on increased temperature. Decreased combined nitrogen supply generally increases CO 2 affinity, decreased iron availability increases CO 2 affinity, and decreased phosphorus supply has varying effects on the organisms examined. There are few data sets showing interactions among the observed changes, and even less information on genetic (adaptation) 2 changes in response to the forcing factors. In freshwaters, changes in phytoplankton species composition may alter with environmental change with consequences for frequency of species with or without CCMs. The information available permits less predictive power as to the effect of the forcing factors on CCM expression than for their overall effects on growth. CCMs are currently not part of models as to how global environmental change has altered, and is likely to further alter, algal and aquatic plant primary productivity.Keywords CO 2 concentrating mechanism -combined nitrogen -inorganic carboniron -mixing depth -photosynthetically active radiation -phosphorus -temperature -UVA-UVB Abbreviations CCM CO 2 concentrating mechanism DOC Dissolved organic carbon PAR Photosynthetically active radiation (400-700 nm)Rubisco Ribulose bisphosphate carboxylase-oxygenase UVA Ultraviolet A radiation (320-400 nm) UVB Ultraviolet B radiation (280-320 nm)

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Excessive irradiance and antioxidant responses of an Antarctic marine diatom exposed to iron limitation and to dynamic irradiance

Cited by 30 publications

References 24 publications

Phytoplankton Virus Production Negatively Affected by Iron Limitation

Phytoplankton Virus Production Negatively Affected by Iron Limitation

Interactive effects of nutrient supply and other environmental factors on the sensitivity of marine primary producers to ultraviolet radiation: implications for the impacts of global change

Algal and aquatic plant carbon concentrating mechanisms in relation to environmental change

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