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| 2. |
- Ianora, Adrianna, et al.
(författare)
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The Relevance of Marine Chemical Ecology to Plankton and Ecosystem Function : An Emerging Field
- 2011
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Ingår i: Marine Drugs. - : MDPI. - 1660-3397. ; 9:9, s. 1625-1648
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Tidskriftsartikel (refereegranskat)abstract
- Marine chemical ecology comprises the study of the production and interaction of bioactive molecules affecting organism behavior and function. Here we focus on bioactive compounds and interactions associated with phytoplankton, particularly bloom-forming diatoms, prymnesiophytes and dinoflagellates. Planktonic bioactive metabolites are structurally and functionally diverse and some may have multiple simultaneous functions including roles in chemical defense (antipredator, allelopathic and antibacterial compounds), and/or cell-to-cell signaling (e.g., polyunsaturated aldehydes (PUAs) of diatoms). Among inducible chemical defenses in response to grazing, there is high species-specific variability in the effects on grazers, ranging from severe physical incapacitation and/or death to no apparent physiological response, depending on predator susceptibility and detoxification capability. Most bioactive compounds are present in very low concentrations, in both the producing organism and the surrounding aqueous medium. Furthermore, bioactivity may be subject to synergistic interactions with other natural and anthropogenic environmental toxicants. Most, if not all phycotoxins are classic secondary metabolites, but many other bioactive metabolites are simple molecules derived from primary metabolism (e.g., PUAs in diatoms, dimethylsulfoniopropionate (DMSP) in prymnesiophytes). Producing cells do not seem to suffer physiological impact due to their synthesis. Functional genome sequence data and gene expression analysis will provide insights into regulatory and metabolic pathways in producer organisms, as well as identification of mechanisms of action in target organisms. Understanding chemical ecological responses to environmental triggers and chemically-mediated species interactions will help define crucial chemical and molecular processes that help maintain biodiversity and ecosystem functionality.
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| 3. |
- Paul, C., et al.
(författare)
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Diatom Derived Polyunsaturated Aldehydes Do Not Structure the Planktonic Microbial Community in a Mesocosm Study
- 2012
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Ingår i: Marine Drugs. - Basel : MDPI AG. - 1660-3397. ; 10:4, s. 775-792
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Tidskriftsartikel (refereegranskat)abstract
- Several marine and freshwater diatoms produce polyunsaturated aldehydes (PUA) in wound-activated processes. These metabolites are also released by intact diatom cells during algal blooms. Due to their activity in laboratory experiments, PUA are considered as potential mediators of diatom-bacteria interactions. Here, we tested the hypothesis that PUA mediate such processes in a close-to-field mesocosm experiment. Natural plankton communities enriched with Skeletonema marinoi strains that differ in their PUA production, a plankton control, and a plankton control supplemented with PUA at natural and elevated concentrations were observed. We monitored bacterial and viral abundance as well as bacterial community composition and did not observe any influence of PUA on these parameters even at elevated concentrations. We rather detected an alternation of the bacterial diversity over time and differences between the two S. marinoi strains, indicating unique dynamic bacterial communities in these algal blooms. These results suggest that factors other than PUA are of significance for interactions between diatoms and bacteria.
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| 4. |
- Saha, M., et al.
(författare)
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Using chemical language to shape future marine health
- 2019
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Ingår i: Frontiers in Ecology and the Environment. - : Wiley. - 1540-9295 .- 1540-9309. ; 17:9, s. 530-537
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Tidskriftsartikel (refereegranskat)abstract
- "Infochemicals" (information-conveying chemicals) dominate much of the underwater communication in biological systems. They influence the movement and behavior of organisms, the ecological interactions between and across populations, and the trophic structure of marine food webs. However, relative to their terrestrial equivalents, the wider ecological and economic importance of marine infochemicals remains understudied and a concerted, cross-disciplinary effort is needed to reveal the full potential of marine chemical ecology. We highlight current challenges with specific examples and suggest how research on the chemical ecology of marine organisms could provide opportunities for implementing new management solutions for future "blue growth" (the sustainable use of ocean resources) and maintaining healthy marine ecosystems.
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| 5. |
- Selander, Erik, 1973, et al.
(författare)
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Solid phase extraction and metabolic profiling of exudates from living copepods
- 2016
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Ingår i: Peerj. - : PeerJ. - 2167-8359. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- Copepods are ubiquitous in aquatic habitats. They exude bioactive compounds that mediate mate finding or induce defensive traits in prey organisms. However, little is known about the chemical nature of the copepod exometabolome that contributes to the chemical landscape in pelagic habitats. Here we describe the development of a closed loop solid phase extraction setup that allows for extraction of exuded metabolites from live copepods. We captured exudates from male and female Temora longicornis and analyzed the content with high resolution LC-MS. Chemometric methods revealed 87 compounds that constitute a specific chemical pattern either qualitatively or quantitatively indicating copepod presence. The majority of the compounds were present in both female and male exudates, but nine compounds were mainly or exclusively present in female exudates and hence potential pheromone candidates. Copepodamide G, known to induce defensive responses in phytoplankton, was among the ten compounds of highest relative abundance in both male and female extracts. The presence of copepodamide G shows that the method can be used to capture and analyze chemical signals from living source organisms. We conclude that solid phase extraction in combination with metabolic profiling of exudates is a useful tool to develop our understanding of the chemical interplay between pelagic organisms.
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| 6. |
- Sjoqvist, C., et al.
(författare)
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Effects of Grazer Presence on Genetic Structure of a Phenotypically Diverse Diatom Population
- 2014
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Ingår i: Microbial Ecology. - : Springer Science and Business Media LLC. - 0095-3628 .- 1432-184X. ; 67:1, s. 83-95
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Tidskriftsartikel (refereegranskat)abstract
- Studies of predator-prey systems in both aquatic and terrestrial environments have shown that grazers structure the intraspecific diversity of prey species, given that the prey populations are phenotypically variable. Populations of phytoplankton have traditionally considered comprising only low intraspecific variation, hence selective grazing as a potentially structuring factor of both genetic and phenotypic diversity has not been comprehensively studied. In this study, we compared strain specific growth rates, production of polyunsaturated aldehydes, and chain length of the marine diatom Skeletonema marinoi in both grazer and non-grazer conditions by conducting monoclonal experiments. Additionally, a mesocosm experiment was performed with multiclonal experimental S. marinoi populations exposed to grazers at different levels of copepod concentration to test effects of grazer presence on diatom diversity in close to natural conditions. Our results show that distinct genotypes of a geographically restricted population exhibit variable phenotypic traits relevant to grazing interactions such as chain length and growth rates. Grazer presence affected clonal richness and evenness of multiclonal Skeletonema populations in the mesocosms, likely in conjunction with intrinsic interactions among the diatom strains. Only the production of polyunsaturated aldehydes was not affected by grazer presence. Our findings suggest that grazing can be an important factor structuring diatom population diversity in the sea and emphasize the importance of considering clonal differences when characterizing species and their role in nature.
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