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- Xiao, Linhong, et al.
(författare)
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Photophysiological response of Symbiodiniaceae single cells to temperature stress
- 2022
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Ingår i: The ISME Journal. - : Springer Nature. - 1751-7362 .- 1751-7370. ; 16:8, s. 2060-2064
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Tidskriftsartikel (refereegranskat)abstract
- Photosynthetic dinoflagellates in the family Symbiodiniaceae engage in symbiosis with scleractinian corals. As coral ‘bleaching’ is partly governed by the thermal sensitivity of different Symbiodiniaceae lineages, numerous studies have investigated their temperature sensitivity. However, the systematic identification of single-cells with increased temperature resistance among these dinoflagellates has remained inaccessible, mostly due to a lack of technologies operating at the microscale. Here, we employed a unique combination of microfluidics, miniaturized temperature control, and chlorophyll fluorometry to characterize the single-cell heterogeneity among five representative species within the Symbiodiniaceae family under temperature stress. We monitored single-cell maximum quantum yields (Fv/Fm) of photosystem (PS) II under increasing temperature stress (22‒39 °C, + 1 °C every 15 min), and detected a significant Fv/Fm reduction at lineage-specific temperatures ranging from 28 °C to 34 °C alongside a 40- to 180- fold increase in intraspecific heterogeneity under elevated temperatures (>31 °C). We discovered that the initial Fv/Fm of a cell could predict the same cell’s ability to perform PSII photochemistry under moderate temperature stress (<32 °C), suggesting its use as a proxy for measuring the thermal sensitivity among Symbiodiniaceae. In combination, our study highlights the heterogeneous thermal sensitivity among photosynthetic Symbiodiniaceae and adds critical resolution to our understanding of temperature-induced coral bleaching.
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| 2. |
- Xiao, Linhong, et al.
(författare)
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Study of the presence of organic UV filters in the Swedish aquatic environment
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Organic UV filters are widely used in personal care products (PCPs) and textiles to prevent solar erythema and discoloration, respectively. These UV absorbing compounds are frequently released into the aquatic environment, either directly via bathing and swimming, or indirectly via effluents from wastewater treatment plants. Because of their widespread occurrence and potential for bioaccumulation, organic UV filters are considered an emerging concern to ecosystems and humans. In this project, we first reviewed and summarized literature on the worldwide occurrence of organic UV filters and subsequently characterized their occurrence in water environments in Uppsala county, Sweden. Specifically, we selected the ten most commonly detected organic UV filters worldwide as our targets. After optimization of chemical analysis, we were able to detect six out of ten of these compounds at environmentally relevant levels. Subsequently, we investigated the occurrence of these six compounds in surface water and sediment samples from bathing/swimming places located at riversides, lakesides, and the seaside around Uppsala county during August 2021. All six organic UV filters (i.e., 4-methylbenzylidene (4-MBC), avobenzone, octinoxate (EHMC), octocrylene (OC), Uvinul A Plus (UVA Plus), benzophenone-4 (BP-4)) were found in sediment and surface water samples with a detection frequency of 100%, except EHMC, which was detected in 71% of the surface water samples. OC dominated in sediment samples collected from bathing/swimming areas with concentrations ranging between 2.6 and 250 ng g‒1 dry weight (dw), which comprised 52-77% of the sum of all targeted compounds. 4-MBC dominated in surface waters with concentrations ranging between 170 ng L‒1 and 560 ng L‒1, which comprised 39-56% of the sum of all targeted compounds. Overall, organic UV filters were ubiquitously detected in Uppsala county and our data could be foundational for an extended sampling campaign and additional risk assessment of organic UV filters among resident aquatic organisms.
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