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Zheng N, Hu W, Liu Y, Li Z, Jiang Y, Bartlam M, Wang Y. Phycospheric bacteria limits the effect of nitrogen and phosphorus imbalance on diatom bloom. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 935:173477. [PMID: 38788949 DOI: 10.1016/j.scitotenv.2024.173477] [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: 01/15/2024] [Revised: 04/23/2024] [Accepted: 05/21/2024] [Indexed: 05/26/2024]
Abstract
Human activities have caused an imbalance in the input nitrogen and phosphorus (N/P) in the biosphere. The imbalance of N/P is one of the characteristics of water eutrophication, which is the fundamental factor responsible for the blooms. The effects of the N/P imbalance on diatom and phycospheric bacteria in blooms are poorly understood. In this study, the N/P molar ratio in real water (14:1) and the predicted N/P molar ratio in future water (65:1) were simulated to analyze the response of Cyclotella sp. and phycospheric bacteria to the N/P imbalance. The results showed that the N/P imbalance inhibited the growth of Cyclotella sp., but prolonged diatom bloom duration. The resistance of Cyclotella sp. to the N/P imbalance is related to phycospheric bacteria, and there are dynamic regulatory mechanisms within the phycospheric bacteria community to resist the N/P imbalance: (1) the increase of HNA bacterial density, the decrease of LNA bacterial density, (2) the increase of phycospheric bacterial diversity and eutrophic bacteria abundance, and the change of denitrifying bacteria abundance, (3) the activity of nitrogen and phosphorus metabolism of HNA bacteria enhanced, while that of LNA bacteria decreased. And the gene hosts of nitrogen and phosphorus metabolism were most enriched in Proteobacteria, indicating that Proteobacteria played an important role in maintaining the stability of phycospheric bacteria and was the dominant phylum resistant to the N/P imbalance. This study clarified that the algal-bacteria system was resistant to the N/P imbalance and implied that the N/P imbalance had little effect on the occurrence of diatom bloom events due to the presence of phycospheric bacteria.
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Affiliation(s)
- Ningning Zheng
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Nankai International Advanced Research Institute (Shenzhen Futian), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| | - Wei Hu
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Nankai International Advanced Research Institute (Shenzhen Futian), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| | - Yu Liu
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Nankai International Advanced Research Institute (Shenzhen Futian), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| | - Zun Li
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Nankai International Advanced Research Institute (Shenzhen Futian), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| | - Yuxin Jiang
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Nankai International Advanced Research Institute (Shenzhen Futian), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| | - Mark Bartlam
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai International Advanced Research Institute (Shenzhen Futian), Nankai University, Tianjin, China.
| | - Yingying Wang
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Nankai International Advanced Research Institute (Shenzhen Futian), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
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Kaleli A, Gozde Ozbayram E, Akcaalan R. Environmental DNA metabarcoding reveals diverse phytoplankton assemblages and potentially harmful algal distribution along the urban coasts of Türkiye. MARINE ENVIRONMENTAL RESEARCH 2024; 199:106623. [PMID: 38917660 DOI: 10.1016/j.marenvres.2024.106623] [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: 03/26/2024] [Revised: 06/13/2024] [Accepted: 06/21/2024] [Indexed: 06/27/2024]
Abstract
Marine phytoplankton are widely used to monitor the state of the water column due to their rapid changes in response to environmental conditions. In this study, we aimed to investigate the coastal phytoplankton assemblages, including bloom-forming species using high-throughput sequencing of 18S rRNA genes targeting the V4 region and their relationship with environmental variables along the Istanbul coasts of the Sea of Marmara. A total of 118 genera belonging to six phyla were detected. Among them, Dinoflagellata (36) and Bacillariophyta (26) were represented with the highest number of genera. According to the relative abundance of DNA reads, the most abundant taxa were Dinoflagellata_phylum (18.1%), Emiliania (8.4%), Biecheleria (8.4), and Noctiluca (8.1%). The ANOSIM test showed that there was a significant temporal difference in the assemblages, while the driving environmental factors were pH, water temperature, and salinity. According to the TRIX index, the trophic state of the coasts was highly mesotrophic and eutrophic. In addition, 45 bloom-forming and HAB taxa were detected and two species of Noctiluca and Emiliania, which frequently cause blooms in the area, were recorded in high abundance. Our results provide insight into the phytoplankton assemblages along the urbanized coastlines by analysing the V4 region of 18S rRNA. This data can support future studies that use both traditional methods and metabarcoding, employing various primers and targeting different genes and regions.
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Affiliation(s)
- Aydın Kaleli
- Istanbul University, Faculty of Aquatic Sciences, Department of Marine and Freshwater Resources Management, 34134, Istanbul, Türkiye.
| | - Emine Gozde Ozbayram
- Istanbul University, Faculty of Aquatic Sciences, Department of Marine and Freshwater Resources Management, 34134, Istanbul, Türkiye.
| | - Reyhan Akcaalan
- Istanbul University, Faculty of Aquatic Sciences, Department of Marine and Freshwater Resources Management, 34134, Istanbul, Türkiye.
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Akbar MA, Mohd Yusof NY, Usup G, Ahmad A, Baharum SN, Bunawan H. Nutrient Deficiencies Impact on the Cellular and Metabolic Responses of Saxitoxin Producing Alexandrium minutum: A Transcriptomic Perspective. Mar Drugs 2023; 21:497. [PMID: 37755110 PMCID: PMC10532982 DOI: 10.3390/md21090497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/11/2023] [Accepted: 07/12/2023] [Indexed: 09/28/2023] Open
Abstract
Dinoflagellate Alexandrium minutum Halim is commonly associated with harmful algal blooms (HABs) in tropical marine waters due to its saxitoxin production. However, limited information is available regarding the cellular and metabolic changes of A. minutum in nutrient-deficient environments. To fill this gap, our study aimed to investigate the transcriptomic responses of A. minutum under nitrogen and phosphorus deficiency. The induction of nitrogen and phosphorus deficiency resulted in the identification of 1049 and 763 differently expressed genes (DEGs), respectively. Further analysis using gene set enrichment analysis (GSEA) revealed 702 and 1251 enriched gene ontology (GO) terms associated with nitrogen and phosphorus deficiency, respectively. Our results indicate that in laboratory cultures, nitrogen deficiency primarily affects meiosis, carbohydrate catabolism, ammonium assimilation, ion homeostasis, and protein kinase activity. On the other hand, phosphorus deficiency primarily affects the carbon metabolic response, cellular ion transfer, actin-dependent cell movement, signalling pathways, and protein recycling. Our study provides valuable insights into biological processes and genes regulating A. minutum's response to nutrient deficiencies, furthering our understanding of the ecophysiological response of HABs to environmental change.
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Affiliation(s)
- Muhamad Afiq Akbar
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia
- Aquatic Animal Health and Therapeutics Laboratory, Institute of Bioscience, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia
- Institute of System Biology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia;
| | - Nurul Yuziana Mohd Yusof
- Department of Earth Science and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia; (N.Y.M.Y.); (G.U.)
| | - Gires Usup
- Department of Earth Science and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia; (N.Y.M.Y.); (G.U.)
| | - Asmat Ahmad
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia;
| | - Syarul Nataqain Baharum
- Institute of System Biology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia;
| | - Hamidun Bunawan
- Institute of System Biology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia;
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Wijaya W, Suhaimi Z, Chua CX, Sunil RS, Kolundžija S, Rohaizat AMB, Azmi NBM, Hazrin-Chong NH, Lauro FM. Frequent pulse disturbances shape resistance and resilience in tropical marine microbial communities. ISME COMMUNICATIONS 2023; 3:55. [PMID: 37280348 PMCID: PMC10244338 DOI: 10.1038/s43705-023-00260-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 05/02/2023] [Accepted: 05/24/2023] [Indexed: 06/08/2023]
Abstract
The Johor Strait separates the island of Singapore from Peninsular Malaysia. A 1-kilometer causeway built in the early 1920s in the middle of the strait effectively blocks water flowing to/from either side, resulting in low water turnover rates and build-up of nutrients in the inner Strait. We have previously shown that short-term rather than seasonal environmental changes influence microbial community composition in the Johor Strait. Here, we present a temporally-intensive study that uncovers the factors keeping the microbial populations in check. We sampled the surface water at four sites in the inner Eastern Johor Strait every other day for two months, while measuring various water quality parameters, and analysed 16S amplicon sequences and flow-cytometric counts. We discovered that microbial community succession revolves around a common stable state resulting from frequent pulse disturbances. Among these, sporadic riverine freshwater input and regular tidal currents influence bottom-up controls including the availability of the limiting nutrient nitrogen and its biological release in readily available forms. From the top-down, marine viruses and predatory bacteria limit the proliferation of microbes in the water. Harmful algal blooms, which have been observed historically in these waters, may occur only when there are simultaneous gaps in the top-down and bottom-up controls. This study gains insight into complex interactions between multiple factors contributing to a low-resistance but high-resilience microbial community and speculate about rare events that could lead to the occurrence of an algal bloom.
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Affiliation(s)
- Winona Wijaya
- Asian School of the Environment, Nanyang Technological University, Singapore, Singapore
| | - Zahirah Suhaimi
- Department of Anthropology, University of California Santa Cruz, Santa Cruz, CA, USA
- Center for Southeast Asian Coastal Interactions, Santa Cruz, CA, USA
| | - Cherlyn Xin'Er Chua
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Rohan Shawn Sunil
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Sandra Kolundžija
- Asian School of the Environment, Nanyang Technological University, Singapore, Singapore
| | | | - Norzarifah Binti Md Azmi
- Department of Biological Sciences and Biotechnology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Nur Hazlin Hazrin-Chong
- Department of Biological Sciences and Biotechnology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Federico M Lauro
- Asian School of the Environment, Nanyang Technological University, Singapore, Singapore.
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore, Singapore.
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