| 1. |
- Aguilera, Anabella, et al.
(författare)
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Ecophysiological analysis reveals distinct environmental preferences in closely related Baltic Sea picocyanobacteria
- 2023
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Ingår i: Environmental Microbiology. - Chichester : John Wiley & Sons. - 1462-2912 .- 1462-2920. ; 25:9, s. 1674-1695
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Tidskriftsartikel (refereegranskat)abstract
- Cluster 5 picocyanobacteria significantly contribute to primary productivity in aquatic ecosystems. Estuarine populations are highly diverse and consist of many co-occurring strains, but their physiology remains largely understudied. In this study, we characterized 17 novel estuarine picocyanobacterial strains. Phylogenetic analysis of the 16S rRNA and pigment genes (cpcBandcpeBA) uncovered multiple estuarine and freshwater-related clusters and pigment types. Assays with five representative strains (three phycocyanin rich and two phycoerythrin rich) under temperature (10–30°C), light(10–190 μmol photons m-2s-1), and salinity (2–14 PSU) gradients revealed distinct growth optima and tolerance, indicating that genetic variability was accompanied by physiological diversity. Adaptability to environmental conditions was associated with differential pigment content and photosynthetic performance. Amplicon sequence variants at a coastal and an offshore station linked population dynamics with phylogenetic clusters, supporting that strains isolated in this study represent key ecotypes within the Baltic Sea picocyanobacterial community. The functional diversity found within strains with the same pigment type suggests that understanding estuarine picocyanobacterial ecology requires analysis beyond the phycocyanin and phycoerythrin divide. This new knowledge of the environmental preferences in estuarine picocyanobacteria is important for understanding and evaluating productivity in current and future ecosystems.
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| 2. |
- Fridolfsson, Emil, et al.
(författare)
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Multiyear analysis uncovers coordinated seasonality in stocks and composition of the planktonic food web in the Baltic Sea proper
- 2023
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Ingår i: Scientific Reports. - London : Springer Nature. - 2045-2322. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- The planktonic realm from bacteria to zooplankton provides the baseline for pelagic aquatic food webs. However, multiple trophic levels are seldomly included in time series studies, hampering a holistic understanding of the influence of seasonal dynamics and species interactions on food web structure and biogeochemical cycles. Here, we investigated plankton community composition, focusing on bacterio-, phyto- and large mesozooplankton, and how biotic and abiotic factors correlate at the Linnaeus Microbial Observatory (LMO) station in the Baltic Sea from 2011 to 2018. Plankton communities structures showed pronounced dynamic shifts with recurring patterns. Summarizing the parts of the planktonic microbial food web studied here to total carbon, a picture emerges with phytoplankton consistently contributing > 39% while bacterio- and large mesozooplankton contributed ~ 30% and ~ 7%, respectively, during summer. Cyanophyceae, Actinobacteria, Bacteroidetes, and Proteobacteria were important groups among the prokaryotes. Importantly, Dinophyceae, and not Bacillariophyceae, dominated the autotrophic spring bloom whereas Litostomatea (ciliates) and Appendicularia contributed significantly to the consumer entities together with the more traditionally observed mesozooplankton, Copepoda and Cladocera. Our findings of seasonality in both plankton composition and carbon stocks emphasize the importance of time series analyses of food web structure for characterizing the regulation of biogeochemical cycles and appropriately constraining ecosystem models.
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| 3. |
- Nham, Thi Quyen, et al.
(författare)
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Whey permeate as a phosphorus source for algal cultivation
- 2023
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Ingår i: Water environment research. - : John Wiley & Sons. - 1061-4303 .- 1554-7531. ; 95:4
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Tidskriftsartikel (refereegranskat)abstract
- Microalgal cultivation for biodiesel and feed requires recycled nutrient resources for a sustainable long-term operation. Whey permeate (WP) from dairy processing contains high organic load (lactose, oils, and proteins) and nitrogen (resources tested for microalgal cultivation) and organic phosphorus (P) that has not yet been tested as a P source for microalgal cultivation. We explored the potential of green algae strains (brackish) and polyculture (freshwater) in exploiting P from WP added to a medium based on either seawater (7 psu) or landfill leachate. Both strains showed a capacity of using organic P in WP with equal growth rates (0.94-1.12 d(-1)) compared with chemical phosphate treatments (0.88-1.07 d(-1)). The polyculture had comparable growth rate (0.25-0.57 d(-1)) and biomass yield (152.1-357.5 mg L-1) and similar or higher nutrient removal rate in the leachate-WP medium (1.3-6.4 mg L-1 day(-1) nitrogen, 0.2-1.1 mg L-1 day(-1) P) compared with the leachate-chemical phosphate medium (1.2-4.7 mg L-1 day(-1) nitrogen, 0.3-1.4 mg L-1 day(-1) P). This study showed that WP is a suitable P source for microalgal cultivation over a range of salinities. To date, this is the first study demonstrating that raw WP can replace mineral P fertilizer for algal cultivation. Practitioners PointsWhey permeate is a comparable phosphorus source to standard fertilizers used in algal cultivation.Green algae removed phosphorus effectively from whey permeate.Microalgal cultivation is a good approach for treatment of whey permeate in combination with a nitrogen-rich wastewater.
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