Ambient Solar Radiation‐Induced Photodamage in Marine Bacterioplankton

Jeffrey, Wade H.; Aas, Peter; Lyons, M. Maille; Coffin, Richard B.; Pledger, Ralph J.; Mitchell, David L.

doi:10.1111/j.1751-1097.1996.tb03086.x

Cited by 117 publications

(103 citation statements)

References 50 publications

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“…Also, the use of Whirlpack bags with lower transmittance to UVBR in the 3 h experiments, compared to polypropylene bags as used in the diurnal experiments, might have contributed to this. Many studies report an inhibitory effect of UVBR on the leucine and thymidine incorporation rates (Bailey et al 1983, Herndl et al 1993, Aas et al 1996, Jeffrey et al 1996a, but inhibition by UVAR and PAR has also been found in olher studies. Sieraciri & Sieburth (1986) showed that UVAR was responsible for the observed growth delay of marine bacteria.…”

Section: Discussionmentioning

confidence: 99%

Effects of UV radiation on DNA photodamage and production in bacterioplankton in the coastal Caribbean Sea

Visser¹,

Snelder²,

Kop³

et al. 1999

Aquat. Microb. Ecol.

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ABSTRACT. This study focuses on the effects of ultraviolet radiation (UVR) on bacterioplankton. The effect of different parts of the sunlight spectrum on the leucine and thymidine incorporation and on the induction of DNA damage in natural bacterial populations in the coastal Caribbean Sea off Curaqao were investigated. DNA photodamage in microorganisms and biodosimeters was quantified by the number of cyclobutane dimers (thymine dimers). Increasing DNA damage during the day was found when incubated in full surface solar radiation. When UVBR was excluded no DNA damage was observed, indicating that thymine dimers were only formed by UVB radiation. The amount of thymine dimers in the > 0 . 8 pm fraction was only one-third of the amount of induced thymine dimers in the <0.8 pm fraction, suggesting that phytoplankton is less sensitive to UV-induced DNA damage than bacterioplankton. Protein and DNA synthesis was inhibited to about 30% of the dark control during the day when exposed to surface solar radiation. In both protein and DNA synthesis a trend was found, with the highest inhibition under full solar radiation, lower inhibition when UVBR was shielded off and the lowest inhibition when UVAR (<375 nm) was also shielded off. The intracellular carbohydrate content of the phytoplankton incubated under full solar radiation was not significantly higher than the dark incubation, while the contents after incubation without UVBR were significantly lngher. The carbohydrate content in the samples incubated without UVBR and UVAR (<375 nm) was a little higher than with only UVBR shielded off. In summary, the results show that in the coastal Caribbean Sea UVBR is responsible for DNA damage in bacterio-and phytoplankton, while protein and DNA synthesis in bacterioplankton was inhibited by UVBR. UVAR and PAR and carbohydrate synthesis in phytoplankton by both UVBR and UVAR.

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Section: Discussionmentioning

confidence: 99%

Effects of UV radiation on DNA photodamage and production in bacterioplankton in the coastal Caribbean Sea

Visser¹,

Snelder²,

Kop³

et al. 1999

Aquat. Microb. Ecol.

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“…Bacterioplankton seem to lack UV-screening pigments such as mycosporines or scytonemins, possibly because of their small size [50,51]. As a consequence, bacterioplankton are more prone to UV-B stress than larger eukaryotic organisms and exposure produces about double the amount of cyclobutane dimers as shown in a case study in the Gulf of Mexico [52,53]. This damage is at least partially offset by photoreactivation [54].…”

Section: Bacterioplankton and Picoplanktonmentioning

confidence: 96%

Effects on aquatic ecosystems

Häder

Kumar

Smith

et al. 1998

Journal of Photochemistry and Photobiology B: Biology

329

160

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Regarding the effects of UV-B radiation on aquatic ecosystems, recent scientific and public interest has focused on marine primary producers and on the aquatic web, which has resulted in a multitude of studies indicating mostly detrimental effects of UV-B radiation on aquatic organisms. The interest has expanded to include ecologically significant groups and major biomass producers using mesocosm studies, emphasizing species interactions. This paper assesses the effects of UV-B radiation on dissolved organic matter, decomposers, primary and secondary producers, and briefly summarizes recent studies in freshwater and marine systems.Dissolved organic carbon (DOC) and particulate organic carbon (POC) are degradation products of living organisms. These substances are of importance in the cycling of carbon in aquatic ecosystems. UV-B radiation has been found to break down high-molecular-weight substances and make them available to bacterial degradation. In addition, DOC is responsible for short-wavelength absorption in the water column. Especially in coastal areas and freshwater ecosystems, penetration of solar radiation is limited by high concentrations of dissolved and particulate matter. On the other hand, climate warming and acidification result in faster degradation of these substances and thus enhance the penetration of UV radiation into the water column.Several research groups have investigated light penetration into the water column. Past studies on UV penetration into the water column were based on temporally and spatially scattered measurements. The process of spectral attenuation of radiant energy in natural waters is well understood and straightforward to model. Less known is the spatial and temporal variability of in-water optical properties influencing UV attenuation and there are few long-term observations. In Europe, this deficiency of measurements is being corrected by a project involving the development of a monitoring system (ELDONET) for solar radiation using three-channel dosimeters (UV-A, UV-B, PAR) that are being installed from Abisko (North Sweden, 688N, 198E) to Tenerife (Canary Islands, 278N, 178W). Some of the instruments have been installed in the water column (North Sea, Baltic Sea, Kattegat, East and Western Mediterranean, North Atlantic), establishing the first network of underwater dosimeters for continuous monitoring.Bacteria play a vital role in mineralization of organic matter and provide a trophic link to higher organisms. New techniques have substantially changed our perception of the role of bacteria in aquatic ecosystems over the recent past and bacterioplankton productivity is far greater than previously thought, having high division and turnover rates. It has been shown that bacterioplankton play a central role in the carbon flux in aquatic ecosystems by taking up DOC and remineralizing the carbon. Bacterioplankton are more prone to UV-B stress than larger eukaryotic organisms and, based on one study, produce about double the amount of cyclobutane dimers. Recently, th...

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“…Bacterial production is inhibited by UV radiation (Herndl et al 1993, Aas et al 1996, Visser et al 1999). UV-B-induced DNA damage has been reported to be higher in small bacterioplankton cells than in larger eukaryotic plankton (Jeffrey et al 1996a) and to fluctuate in a diel pattern (Jeffrey et al 1996b). Damage was seen to accumulate during the afternoon hours but then be repaired between sunset and the following sunrise.…”

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confidence: 92%

Quantification of recA gene expression as an indicator of repair potential in marine bacterioplankton communities of Antarctica

Booth¹,

Hutchinson²,

Brumsted³

et al. 2001

Aquat. Microb. Ecol.

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Marine bacteria in surface waters must cope daily with the damaging effects of exposure to solar radiation (containing both UV-A and UV-B wavelengths), which produces lesions in their DNA. As the stratospheric ozone layer is depleted, these coping mechanisms are likely to play an even more important role in the viability of marine bacterial communities. The recA gene is ubiquitous among eubacteria and is highly conserved both in nucleotide and amino acid sequence. Besides its role in generalized recombination, the gene's translational product, RecA, is the regulator of 'dark repair' activity (DNA-repair mechanisms that do not require visible light as a cofactor). We have taken advantage of this function and used recA gene expression as a barometer of the DNAdamage repair capacity of bacterial assemblages in the Southern Ocean. Studies were conducted in the Gerlache Strait, Antarctica, in the austral springs of 1995 and 1996. Analysis of both recA mRNA and RecA protein extracted from natural communities indicated that the level of expression of this gene varied in a diel fashion, suggesting an increased repair capacity in these organisms. These included an early morning rise in RecA levels followed by a plateau or even a reduction in RecA concentration during the remainder of the day. A much greater increase in RecA was consistently observed after sunset, followed by a constant decrease during the night. Microcosm experiments with a RecA + Gerlache Strait γ-proteobacteria isolate, RM11001, demonstrated a similar diel pattern of expression. These studies demonstrate the usefulness of RecA as a biological indicator of DNA repair capacity in natural bacterial assemblages. They indicate that 'dark repair' of DNA damage is an important coping mechanism for bacteria in the marine environment of Antarctica.KEY WORDS: Southern Ocean · Antarctica · Solar UV radiation · DNA repair · Marine bacterioplankton communities · recA gene · RecA protein Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 24: [51][52][53][54][55][56][57][58][59] 2001 Solar UV radiation consists of UV-C (100 to 280 nm), UV-B (280 to 320 nm), and UV-A (320 to 400 nm) (Peak & Peak 1983). UV-C is environmentally irrelevant because it does not penetrate the earth's atmosphere. UV-B is selectively absorbed by ozone and increases significantly during ozone depletion events (Stolarski 1988). Longer UV-A wavelengths are unaffected by changes in column ozone (Stolarski 1988).Recent evidence suggests that UV-B may have significant effects on marine microbial communities. Phytoplankton and primary production have been the focus of the majority of previous studies (Bidigare 1989, Marchant et al. 1991, Holm-Hansen et al. 1993, Schick et al. 1995, Forster & Lüning 1996, Herrmann et al. 1997, Holm-Hansen 1997, Zagarese et al. 1997, while significantly less is known about UV radiation effects on bacterioplankton in the Southern Ocean. Helbling et al. (1995) reported that viability, based on colony-forming uni...

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Ambient Solar Radiation‐Induced Photodamage in Marine Bacterioplankton

Cited by 117 publications

References 50 publications

Effects of UV radiation on DNA photodamage and production in bacterioplankton in the coastal Caribbean Sea

Effects of UV radiation on DNA photodamage and production in bacterioplankton in the coastal Caribbean Sea

Effects on aquatic ecosystems

Quantification of recA gene expression as an indicator of repair potential in marine bacterioplankton communities of Antarctica

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