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Jégou C, Connan S, Bihannic I, Cérantola S, Guérard F, Stiger-Pouvreau V. Phlorotannin and Pigment Content of Native Canopy-Forming Sargassaceae Species Living in Intertidal Rockpools in Brittany (France): Any Relationship with Their Vertical Distribution and Phenology? Mar Drugs 2021; 19:504. [PMID: 34564166 PMCID: PMC8469379 DOI: 10.3390/md19090504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/30/2021] [Accepted: 09/02/2021] [Indexed: 11/16/2022] Open
Abstract
Five native Sargassaceae species from Brittany (France) living in rockpools were surveyed over time to investigate photoprotective strategies according to their tidal position. We gave evidences for the existence of a species distribution between pools along the shore, with the most dense and smallest individuals in the highest pools. Pigment contents were higher in lower pools, suggesting a photo-adaptive process by which the decreasing light irradiance toward the low shore was compensated by a high production of pigments to ensure efficient photosynthesis. Conversely, no xanthophyll cycle-related photoprotective mechanism was highlighted because high levels of zeaxanthin rarely occurred in the upper shore. Phlorotannins were not involved in photoprotection either; only some lower-shore species exhibited a seasonal trend in phlorotannin levels. The structural complexity of phlorotannins appears more to be a taxonomic than an ecological feature: Ericaria produced simple phloroglucinol while Cystoseira and Gongolaria species exhibited polymers. Consequently, tide pools could be considered as light-protected areas on the intertidal zone, in comparison with the exposed emerged substrata where photoprotective mechanisms are essential.
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Affiliation(s)
- Camille Jégou
- Laboratoire de Biotechnologie et Chimie Marine (LBCM) EA 3884, Université de Brest, 6 Rue de l’université, F-29334 Quimper, France;
| | - Solène Connan
- Laboratoire des Sciences de l’Environnement (LEMAR) UMR 6539, Université de Brest, CNRS, IRD, Ifremer, F-29280 Plouzane, France; (S.C.); (I.B.); (F.G.)
| | - Isabelle Bihannic
- Laboratoire des Sciences de l’Environnement (LEMAR) UMR 6539, Université de Brest, CNRS, IRD, Ifremer, F-29280 Plouzane, France; (S.C.); (I.B.); (F.G.)
| | | | - Fabienne Guérard
- Laboratoire des Sciences de l’Environnement (LEMAR) UMR 6539, Université de Brest, CNRS, IRD, Ifremer, F-29280 Plouzane, France; (S.C.); (I.B.); (F.G.)
| | - Valérie Stiger-Pouvreau
- Laboratoire des Sciences de l’Environnement (LEMAR) UMR 6539, Université de Brest, CNRS, IRD, Ifremer, F-29280 Plouzane, France; (S.C.); (I.B.); (F.G.)
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García-Seoane R, Fernández JA, Boquete MT, Aboal JR. Analysis of intra-thallus and temporal variability of trace elements and nitrogen in Fucus vesiculosus: Sampling protocol optimization for biomonitoring. JOURNAL OF HAZARDOUS MATERIALS 2021; 412:125268. [PMID: 33951869 DOI: 10.1016/j.jhazmat.2021.125268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 01/25/2021] [Accepted: 01/27/2021] [Indexed: 06/12/2023]
Abstract
To advance the methodological standardization of the biomonitoring technique using macroalgae, we comprehensively characterized the intra-thallus and temporal patterns of variation in concentrations of a wide set of elements (Al, As, Cd, Co, Cr, Cu, Fe, Hg, Ni, Pb, Zn, N) and δ15N signal in 6 consecutive Fucus vesiculosus apical dichotomous sections collected monthly over a four-year period (2015-2019) at 3 sites on the NW coast of Spain. The concentrations of Al, Co, Fe, Ni, Pb and Zn increased significantly from the youngest to the oldest dichotomies regardless of the sampling time and collection site; As, Cd, N and δ15N showed the opposite trend. Time series analysis revealed a significant and consistent seasonal variation of As, Cd, Co, Cu, Fe, Hg, Ni, Zn, N and δ15N concentrations, with maximum values in winter and minimum values in summer. We discussed the possible mechanisms driving these two sources of variation, and proposed an efficient and effective sampling strategy to minimize their impact in the results of biomonitoring studies, in which the part of the algal thallus selected for chemical analysis and the sampling frequency were carefully considered. This protocol will improve the conclusions and comparability of biomonitoring data from coastal environments.
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Affiliation(s)
- R García-Seoane
- CRETUS Institute, Department of Functional Biology, Ecology Unit, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
| | - J A Fernández
- CRETUS Institute, Department of Functional Biology, Ecology Unit, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - M T Boquete
- Estación Biológica de Doñana, CSIC, Avenida Américo Vespucio 26, 41092 Sevilla, Spain
| | - J R Aboal
- CRETUS Institute, Department of Functional Biology, Ecology Unit, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
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Physiological responses and productivity of the seaweed Ulva ohnoi (Chlorophyta) under changing cultivation conditions in pilot large land-based ponds. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102316] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Eismann AI, Perpetuo Reis R, Ferreira da Silva A, Negrão Cavalcanti D. Ulva spp. carotenoids: Responses to environmental conditions. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.101916] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Usandizaga S, Camus C, Kappes JL, Guillemin ML, Buschmann AH. Nutrients, but not genetic diversity, affect Gracilaria chilensis (Rhodophyta) farming productivity and physiological responses. JOURNAL OF PHYCOLOGY 2018; 54:860-869. [PMID: 30222862 DOI: 10.1111/jpy.12785] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 09/04/2018] [Indexed: 06/08/2023]
Abstract
In terrestrial plants, it is well known that genetic diversity can affect responses to abiotic and biotic stress and have important consequences on farming. However, very little is known about the interactive effects of genetic and environmental factors on seaweed crops. We conducted a field experiment on Gracilaria chilensis to determine the effect of heterozygosity and nutrient addition on two southern Chilean farms: Ancud and Chaica. In addition to growth rate and productivity, we measured photosynthetic responses, photosynthetic pigment concentration (chlorophyll a and phycobiliproteins), C:N ratio (C:N), and epiphytic load. Nutrient addition affected the growth rate, productivity, phycobilin, and C:N content, but not the epiphytic load. These results were independent of the heterozygosity of the strains used in the experiments. Interestingly, depending on the sampled sites, distinct photosynthetic responses (i.e., maximal quantum yield, Fv /Fm , and maximal electron transport rate, ETRmax ) to nutrient addition were observed. We propose that thallus selection over the past few decades may have led to ecological differentiation between G. chilensis from Chaica and Ancud. The lack of effect of heterozygosity on growth and physiological responses could be related to the species domestication history in which there is a limited range of genetic variation in farms. We suggest that the existing levels of heterozygosity among our thalli is not sufficient to detect any significant effect of genetic diversity on growth or productivity in Metri bay, our experimental site located close to the city of Puerto Montt, during summer under nitrogen limiting conditions.
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Affiliation(s)
- Sara Usandizaga
- Programa de Doctorado en Ciencias, mención Conservación y Manejo de Recursos Naturales, Centro i˜mar and CeBiB, Universidad de Los Lagos, Camino Chinquihue Km 6, Puerto Montt, Chile
| | - Carolina Camus
- Centro i˜mar and CeBiB, Universidad de Los Lagos, Camino Chinquihue Km 6, Puerto Montt, Chile
| | - José Luis Kappes
- Centro i˜mar and CeBiB, Universidad de Los Lagos, Camino Chinquihue Km 6, Puerto Montt, Chile
| | - Marie Laure Guillemin
- Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
- CNRS, Sorbonne Université, Pontificia Universidad Catolica de Chile, Universidad Austral de Chile, UMI Evolutionary Biology and Ecology of Algae, Station Biologique de Roscoff, 29680, Roscoff, France
| | - Alejandro H Buschmann
- Centro i˜mar and CeBiB, Universidad de Los Lagos, Camino Chinquihue Km 6, Puerto Montt, Chile
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Carballeira C, Rey-Asensio A, Carballeira A. Interannual changes in δ¹⁵N values in Fucus vesiculosus L. MARINE POLLUTION BULLETIN 2014; 85:141-5. [PMID: 24997874 DOI: 10.1016/j.marpolbul.2014.06.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Revised: 06/04/2014] [Accepted: 06/09/2014] [Indexed: 06/03/2023]
Abstract
The natural abundance of (15)N (δ(15)N) has been widely used to detect anthropogenically derived N loads in environmental impact studies. The present study involved retrospective analysis of subsamples of Fucus vesiculosus L. collected during a period of three years (2008-2010) from two sites: a control site, within a coastal reference area, and an area affected by the effluents of a marine land-based fish farm. The isotopic signal in different subsamples of the macroalgae thalli (tissue that has grown during the same period) varied depending on the age of the tissue. Moreover, the isotopic signal decreased significantly with the age of the frond to within a certain range. The δ(15)N of F. vesiculosus is temporally unstable; therefore, measurement of the δ(15)N of macroalgal tissues does not allow reliable retrospective biomonitoring of environmental pollution. Further knowledge about the growth and other biological aspects of this species is required.
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Affiliation(s)
- Carlos Carballeira
- Área de Ecología, Facultad de Biología, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
| | - Ana Rey-Asensio
- Área de Ecología, Facultad de Biología, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Alejo Carballeira
- Área de Ecología, Facultad de Biología, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
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Konotchick T, Dupont CL, Valas RE, Badger JH, Allen AE. Transcriptomic analysis of metabolic function in the giant kelp, Macrocystis pyrifera, across depth and season. THE NEW PHYTOLOGIST 2013; 198:398-407. [PMID: 23488966 PMCID: PMC3644879 DOI: 10.1111/nph.12160] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 12/10/2012] [Indexed: 05/30/2023]
Abstract
To increase knowledge of transcript diversity for the giant kelp, Macrocystis pyrifera, and assess gene expression across naturally occurring depth gradients in light, temperature and nutrients, we sequenced four cDNA libraries created from blades collected at the sea surface and at 18 m depth during the winter and summer. Comparative genomics cluster analyses revealed novel gene families (clusters) in existing brown alga expressed sequence tag data compared with other related algal groups, a pattern also seen with the addition of M. pyrifera sequences. Assembly of 228 Mbp of sequence generated c. 9000 isotigs and c. 12,000 open reading frames. Annotations were assigned using families of hidden Markov models for c. 11% of open reading frames; M. pyrifera had highest similarity to other members of the Phaeophyceae, namely Ectocarpus siliculosus and Laminaria digitata. Quantitative polymerase chain reaction of transcript targets verified depth-related differences in gene expression; stress response and light-harvesting transcripts, especially members of the LI818 (also known as LHCSR) family, showed high expression in the surface compared with 18 m depth, while some nitrogen acquisition transcripts (e.g. nitrite reductase) were upregulated at depth compared with the surface, supporting a conceptual biological model of depth-dependent physiology.
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Affiliation(s)
- Talina Konotchick
- J. Craig Venter Institute, 10355 Science Center Drive, San Diego, CA, USA
| | | | - Ruben E Valas
- J. Craig Venter Institute, 10355 Science Center Drive, San Diego, CA, USA
| | - Jonathan H Badger
- J. Craig Venter Institute, 10355 Science Center Drive, San Diego, CA, USA
| | - Andrew E Allen
- J. Craig Venter Institute, 10355 Science Center Drive, San Diego, CA, USA
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Xu Z, Gao K. NH4+ enrichment and UV radiation interact to affect the photosynthesis and nitrogen uptake of Gracilaria lemaneiformis (Rhodophyta). MARINE POLLUTION BULLETIN 2012; 64:99-105. [PMID: 22104717 DOI: 10.1016/j.marpolbul.2011.10.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Accepted: 10/17/2011] [Indexed: 05/31/2023]
Abstract
Solar ultraviolet radiation (UVR, 280-400 nm) is known to inhibit the photosynthesis of macroalgae, whereas nitrogen availability may alter the sensitivity of the algae to UVR. Here, we show that UV-B (280-315 nm) significantly reduced the net photosynthetic rate of Gracilaria lemaneiformis. This inhibition was alleviated by enrichment with ammonia, which also caused a decrease in dark respiration. The presence of both UV-A (315-400 nm) and UV-B stimulated the accumulation of UV-absorbing compounds. However, this stimulation was not affected by enrichment with ammonia. The content of phycoerythrin (PE) was increased by the enrichment of ammonia only in the absence of UVR. Ammonia uptake and the activity of nitrate reductase were repressed by UVR. However, exposure to UVR had an insignificant effect on the rate of nitrate uptake. In conclusion, increased PE content associated with ammonia enrichment played a protective role against UVR in this alga, and UVR differentially affected the uptake of nitrate and ammonia.
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Affiliation(s)
- Zhiguang Xu
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian 361005, China; Mariculture Institute of Shandong Province, Qingdao, Shandong 266002, China.
| | - Kunshan Gao
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian 361005, China.
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Case RJ, Longford SR, Campbell AH, Low A, Tujula N, Steinberg PD, Kjelleberg S. Temperature induced bacterial virulence and bleaching disease in a chemically defended marine macroalga. Environ Microbiol 2010; 13:529-37. [PMID: 20946533 DOI: 10.1111/j.1462-2920.2010.02356.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Host-pathogen interactions have been widely studied in humans and terrestrial plants, but are much less well explored in marine systems. Here we show that a marine macroalga, Delisea pulchra, utilizes a chemical defence - furanones - to inhibit colonization and infection by a novel bacterial pathogen, Ruegeria sp. R11, and that infection by R11 is temperature dependent. Ruegeria sp. R11 formed biofilms, invaded and bleached furanone-free, but not furanone-producing D. pulchra thalli, at high (24°C) but not low (19°C) temperatures. Bleaching is commonly observed in natural populations of D. pulchra near Sydney, Australia, during the austral summer when ocean temperatures are at their peak and the chemical defences of the alga are reduced. Furanones, produced by D. pulchra as a chemical defence, inhibit quorum sensing (QS) in bacteria, and this may play a role in furanone inhibition of R11 infection of furanone-free thalli as R11 produces QS signals. This interplay between temperature, an algal chemical defence mechanism and bacterial virulence demonstrates the complex impact environmental change can have on an ecosystem.
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Affiliation(s)
- Rebecca J Case
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
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10
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Figueroa FL, Israel A, Neori A, Martínez B, Malta EJ, Put A, Inken S, Marquardt R, Abdala R, Korbee N. Effect of nutrient supply on photosynthesis and pigmentation to short-term stress (UV radiation) in Gracilaria conferta (Rhodophyta). MARINE POLLUTION BULLETIN 2010; 60:1768-1778. [PMID: 20619863 DOI: 10.1016/j.marpolbul.2010.06.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Revised: 06/09/2010] [Accepted: 06/14/2010] [Indexed: 05/29/2023]
Abstract
The effects of increased photosynthetic active radiation (PAR), UV radiation (UVR), and nutrient supply on photosynthetic activity, pigment content, C:N ratio and biomass yield were studied in tank cultivated Gracilaria conferta (Rhodophyta). Electron transport rate (ETR) and biliprotein content were higher under high nutrient supply (HNS), obtained from fishpond effluents, compared to low nutrient supply (LNS), in contrast to mycosporine-like amino acids (MAAs) dynamic. The high MAA content in LNS-algae could be explained by higher UVR penetration in the thallus and by the competition for the use of nutrients with other processes. Effective quantum yield decreased after short-term exposure to high irradiance whereas full recovery in shade was produced only under slightly heat shock. UVA radiation provoked an additional decrease in photosynthesis under high water temperature. UVB radiation reversed UVA's negative effect mainly with HNS. Results support that nutrient-sufficiency help G. conferta to resist environmental changes as short-term temperature increase.
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Affiliation(s)
- F L Figueroa
- Department of Ecology, Faculty of Sciences, University of Málaga, Campus Universitario de Teatinos s/n, 29071 Málaga, Spain
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Xue L, Zhang Y, Zhang T, An L, Wang X. Effects of Enhanced Ultraviolet-B Radiation on Algae and Cyanobacteria. Crit Rev Microbiol 2008; 31:79-89. [PMID: 15986833 DOI: 10.1080/10408410590921727] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
This article provides an overview of existing literature on the ultraviolet-B (UV-B) radiation effects on algae and cyanobacteria. We report on the effects of UV-B radiation to the growth and development, biomass, sensitivity, photosynthetic pigments, UV-B absorbing compounds, photosynthesis, protein and DNA damage, enzyme activity, nitrogen fixation and assimilation of nitrogen, protective mechanisms of algae and cyanobacteria, the accommodation of algae and cyanobacteria to environmental stress, and the effects to ecology system. Many of the studies show the dramatic effects of UV-B radiation; but typically these studies were conducted under conditions with supplemental UV-B irradiance that was higher than would ever occur outside experimental conditions or natural condition. A few of the studies reviewed used experimental conditions and supplemental UV-B irradiance that approached realism. Enhanced UV-B generally decreased chlorophyll content, whereas it increased UV-B absorbing compounds in many algae. Decrease in photosynthesis, particularly at higher UV-B doses, was due to both direct (effect on photosystem) and indirect (decrease in pigments) effects. The decreases in chlorophyll pigments and photosynthesis resulted in lower biomass. However, algae and cyanobacteria have evolved various avoidance and repair mechanisms to protect themselves against the damaging effects of UV radiation to acclimate to enhanced UV-B radiation. The review points to areas where further studies on the relationships among nitrogenase, Rubisco, antioxidase activity, signal, antioxidants, and free radicals under enhanced UV-B are needed to quantify the effects of UV-B radiation on algae and cyanobacteria. These studies are needed in order to develop dose response functions that can facilitate development of dynamic simulation models for use in UV-B and other environmental impact assessments.
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Affiliation(s)
- Lingui Xue
- State Key Laboratory of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China
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Helbling EW, Barbieri ES, Sinha RP, Villafañe VE, Häder DP. Dynamics of potentially protective compounds in Rhodophyta species from Patagonia (Argentina) exposed to solar radiation. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2004; 75:63-71. [PMID: 15246352 DOI: 10.1016/j.jphotobiol.2004.05.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2003] [Revised: 01/16/2004] [Accepted: 05/18/2004] [Indexed: 10/26/2022]
Abstract
The impact of solar radiation upon potentially protective compounds (i.e., UV-absorbing compounds and carotenoids) was assessed in four Rhodophyte species from Patagonia (i.e., Ceramium sp. Lyngbye, Corallina officinalis Linnaeus, Callithamnion gaudichaudii Agardh and Porphyra columbina Montagne) during short-term (i.e., 46 h) experiments. Algae were exposed to solar radiation under two treatments (PAR only: 400-700 nm, and PAR+UVR: 280-700 nm) and sub-samples were taken every 3 h (or longer periods at night) to determine the spectral absorption characteristics and concentration of UV-absorbing compounds, carotenoids and photosynthetic pigments. Except for C. gaudichaudii which displayed a decrease in chl-a concentration throughout the experiment, photosynthetic pigments had small variations in all species. UV-absorbing compounds concentration had species-specific responses: Ceramium sp. was the only species in which UV-absorbing compounds concentration varied as a function of solar irradiance, with maximum values around local noon. In C. officinalis and P. columbina UV-absorbing compounds concentration increased as compared to that of chl-a; in Ceramium sp. and C. gaudichaudii, however, there was no relationship between UV-absorbing compounds content and chl-a concentration. Carotenoids, on the other hand, did co-vary with chl-a in all species. Our data suggest that, with the exception of C. gaudichaudii, the differential responses of UV-absorbing compounds concentrations are more associated to the previous light history of the algae (i.e., in turn due to their position in the intertidal zone) rather than to the radiation treatment imposed to the samples. Based on our results, the variable impact of solar radiation upon productivity (and eventually biodiversity) of macroalgae from Patagonia might consequently differentially affect higher trophic levels of the aquatic food web.
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Affiliation(s)
- E Walter Helbling
- Estación de Fotobiología Playa Unión and Consejo Nacional de Investigaciones Científicas y Técnicas, Rifleros 227 - Playa Unión, Rawson, Chubut, Argentina.
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14
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Effects of solar radiation on photosynthesis, UV-absorbing compounds and enzyme activities of the green alga Dasycladus vermicularis from southern Spain. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 1998. [DOI: 10.1016/s1011-1344(98)00199-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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16
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Häder DP, Kumar H, Smith R, Worrest R. Effects on aquatic ecosystems. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 1998. [DOI: 10.1016/s1011-1344(98)00185-7] [Citation(s) in RCA: 252] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Ochs CA, Eddy LP. Effects of UV-A (320 to 399 Nanometers) on Grazing Pressure of a Marine Heterotrophic Nanoflagellate on Strains of the Unicellular Cyanobacteria
Synechococcus
spp. Appl Environ Microbiol 1998; 64:287-93. [PMID: 16349489 PMCID: PMC124707 DOI: 10.1128/aem.64.1.287-293.1998] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ABSTRACT
In the open ocean, where turbidity is very low, UV radiation may be an important factor regulating interactions among planktonic microorganisms. The effect of exposure to UV radiation on grazing by a commonly isolated marine heterotrophic nanoflagellate,
Paraphysomonas bandaiensis
, on two strains of the cyanobacteria
Synechococcus
spp. was investigated. Laboratory cultures were exposed to a range of irradiances of artificially produced UV-B (290 to 319 nm) and UV-A (320 to 399 nm) for up to 10 h. At a UV-B irradiance of 0.19 W m
−2
, but not 0.12 W m
−2
, grazing mortality of
Synechococcus
spp. and nanoflagellate-specific grazing rates were reduced compared to mortality and grazing rates with UV-A treatment. Within 6 h of exposure, UV-A alone suppressed grazing mortality at irradiances as low as 3.02 W m
−2
. The extent to which grazing mortality and nanoflagellate-specific grazing rates were suppressed by UV-A increased with both irradiance and duration of exposure. Over a 6-h exposure period, differences in grazing mortality were largely attributable to differential survival of nanoflagellates. Over a longer period of exposure, there was impairment by UV-A alone of nanoflagellate-specific grazing rates. Rates of primary productivity of
Synechococcus
spp. were also reduced by UV-A. The extent to which
Synechococcus
productivity was reduced, compared to the reduction in
Synechococcus
grazing mortality, depended on the duration of UV-A exposure. These results support the hypothesis that UV-A alone influences the composition and biomass of marine microbial communities by affecting predator-prey interactions and primary production.
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Affiliation(s)
- C A Ochs
- Department of Biology, University of Mississippi, University, Mississippi 38677
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Influence of UV radiation on the photosynthesis of arctic macroalgae in the field. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 1997. [DOI: 10.1016/s1011-1344(96)07415-5] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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