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Hanžek N, Šiljeg M, Šikić T, Stanković I. Phytoplankton in Deep Lakes of the Dinaric Karst: Functional Biodiversity and Main Ecological Features. PLANTS (BASEL, SWITZERLAND) 2024; 13:2252. [PMID: 39204688 PMCID: PMC11360328 DOI: 10.3390/plants13162252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2024] [Revised: 08/06/2024] [Accepted: 08/08/2024] [Indexed: 09/04/2024]
Abstract
Phytoplankton is a polyphyletic group of organisms that responds rapidly to environmental conditions and provides a reliable response to changes, making it a good ecological indicator for water quality monitoring. However, a gradient is almost essential for a reliable relationship between pressure and impact. In a low-gradient environment, ingenuity is required to outsmart the limitations of the commonly used linear relationship. Here, we examine changes in biomass and functional biodiversity by analysing larger data sets (2013-2022) in six ecologically diverse, natural, deep Croatian karst lakes with low nutrient gradients using nonlinear correlation coefficients and multivariate analyses in 209 samples. We found that phytoplankton biomass was most strongly influenced by nutrients, salinity and alkalinity, while light availability and total nitrogen strongly influenced phytoplankton functional biodiversity. An additional analysis of the TN:TP ratio revealed that the oligotrophic Lake Vransko is nitrogen-limited, and lakes Kozjak and Prošće are phosphorus-limited. This further clarified the relationship of phytoplankton to nutrients despite the low gradient. The complex analysis in this study provides a new perspective for predicting changes in the structure and succession of phytoplankton in deep karst lakes for successful management under apparent anthropogenic pressure and climate change.
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Affiliation(s)
| | | | | | - Igor Stanković
- Josip Juraj Strossmayer Water Institute, Ulica grada Vukovara 220, 10000 Zagreb, Croatia; (N.H.); (M.Š.); (T.Š.)
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Lin X, Wu M, Shao X, Li G, Hong Y. Water turbidity dynamics using random forest in the Yangtze River Delta Region, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 903:166511. [PMID: 37633384 DOI: 10.1016/j.scitotenv.2023.166511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 08/20/2023] [Accepted: 08/21/2023] [Indexed: 08/28/2023]
Abstract
Turbidity is a water quality indicator that is essential for the sustainable development of aquatic ecosystems and the protection of biodiversity. The turbidity of different water surfaces and its response mechanisms to regional climatic factors and human activities in the Yangtze River Delta Region (YRDR), an important rapid economic development region in China, remain poorly understood. To enhance the knowledge of turbidity variations and dominant drivers of YRDR water surfaces, a complete long-term turbidity series was obtained using Landsat images from 1990 to 2020. The results show that the turbidity trend differed from -1.3 NTU/yr to 0.7 NTU/yr in different water surfaces. Turbidity decreased significantly in the mainstream of the Yangtze River (MYR), aquaculture ponds (AP) and other water bodies, whilst increasing significantly in the medium lakes (ML) and mainstream of the Qiantang River (MQR). Meanwhile, no significant changes in turbidity were observed in the great lakes (GL) and small lakes (SL). Rather than climatic factors, urbanisation and decreasing wastewater discharge were the dominant drivers of turbidity trends during the study period. In addition, ecological engineering in AP increased water transparency. The Three Gorges Dam also decreased turbidity in MYR. Increasing turbidity in the downstream of MQR was driven by increasing seasonal water surfaces and reclamation projects near Hangzhou Bay. GL faced no significant increase in turbidity due to the offset of afforestation to urbanisation-induced turbidity increase. These findings provide important information for government decision-making for subsequent aquatic environmental protection and restoration in the YRDR.
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Affiliation(s)
- Xingna Lin
- Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China.
| | - Ming Wu
- Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China.
| | - Xuexin Shao
- Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China
| | - Guozhi Li
- East China Academy of Inventory and Planning, National Forestry and Grassland Administration, Hangzhou 311400, China
| | - Yifeng Hong
- East China Academy of Inventory and Planning, National Forestry and Grassland Administration, Hangzhou 311400, China.
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3
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O'Brien DA, Deb S, Gal G, Thackeray SJ, Dutta PS, Matsuzaki SIS, May L, Clements CF. Early warning signals have limited applicability to empirical lake data. Nat Commun 2023; 14:7942. [PMID: 38040724 PMCID: PMC10692136 DOI: 10.1038/s41467-023-43744-8] [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: 05/22/2023] [Accepted: 11/17/2023] [Indexed: 12/03/2023] Open
Abstract
Research aimed at identifying indicators of persistent abrupt shifts in ecological communities, a.k.a regime shifts, has led to the development of a suite of early warning signals (EWSs). As these often perform inaccurately when applied to real-world observational data, it remains unclear whether critical transitions are the dominant mechanism of regime shifts and, if so, which EWS methods can predict them. Here, using multi-trophic planktonic data on multiple lakes from around the world, we classify both lake dynamics and the reliability of classic and second generation EWSs methods to predict whole-ecosystem change. We find few instances of critical transitions, with different trophic levels often expressing different forms of abrupt change. The ability to predict this change is highly processing dependant, with most indicators not performing better than chance, multivariate EWSs being weakly superior to univariate, and a recent machine learning model performing poorly. Our results suggest that predictive ecology should start to move away from the concept of critical transitions, developing methods suitable for predicting resilience loss not limited to the strict bounds of bifurcation theory.
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Affiliation(s)
- Duncan A O'Brien
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK.
| | - Smita Deb
- Department of Mathematics, Indian Institute of Technology Ropar, Rupnagar, Punjab, 140001, India
| | - Gideon Gal
- Kinneret Limnological Laboratory, Israel Oceanographic & Limnological Research, PO Box 447, Migdal, Israel
| | - Stephen J Thackeray
- Lake Ecosystems Group, UK Centre for Ecology & Hydrology, Bailrigg, Lancaster, UK
| | - Partha S Dutta
- Department of Mathematics, Indian Institute of Technology Ropar, Rupnagar, Punjab, 140001, India
| | - Shin-Ichiro S Matsuzaki
- Biodiversity Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - Linda May
- UK Centre for Ecology & Hydrology, Bush Estate, Penicuik, Midlothian, EH26 OQB, UK
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Yao EK, Ahoutou MK, Olokotum M, Hamlaoui S, Lance E, Marie B, Bernard C, Djeha RY, Quiblier C, Humbert JF, Coulibaly JK. Assessment of cyanotoxins in water and fish in an African freshwater lagoon (Lagoon Aghien, Ivory Coast) and the application of WHO guidelines. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:97857-97871. [PMID: 37603248 DOI: 10.1007/s11356-023-29025-3] [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: 05/09/2023] [Accepted: 07/24/2023] [Indexed: 08/22/2023]
Abstract
In comparison with northern countries, limited data are available on the occurrence and potential toxicity of cyanobacterial blooms in lakes and ponds in sub-Saharan countries. With the aim of enhancing our knowledge on cyanobacteria and their toxins in Africa, we performed a 17-month monitoring of a freshwater ecosystem, Lagoon Aghien (Ivory Coast), which is used for multiple practices by riverine populations and for drinking water production in Abidjan city. The richness and diversity of the cyanobacterial community were high and displayed few variations during the entire survey. The monthly average abundances ranged from 4.1 × 104 to 1.8 × 105 cell mL-1, with higher abundances recorded during the dry seasons. Among the five cyanotoxin families analyzed (anatoxin-a, cylindrospermopsin, homoanatoxin, microcystins, saxitoxin), only microcystins (MC) were detected with concentrations ranging from 0 to 0.364 μg L-1 in phytoplankton cells, from 32 to 1092 μg fresh weight (FW) kg-1 in fish intestines, and from 33 to 383 μg FW kg-1 in fish livers. Even if the MC concentrations in water and fish are low, usually below the thresholds defined in WHO guidelines, these data raise the issue of the relevance of these WHO guidelines for sub-Saharan Africa, where local populations are exposed throughout the year to these toxins in multiple ways.
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Affiliation(s)
| | - Mathias Koffi Ahoutou
- Institut Pasteur de Côte d'Ivoire, Abidjan, Côte d'Ivoire
- Université Jean Lorougnon Guédé, Daloa, Côte d'Ivoire
| | - Mark Olokotum
- National Fisheries Resources Research Institute, Jinja, Uganda
- Department of Zoology, Entomology and Fisheries Sciences, Makerere University, Kampala, Uganda
| | - Sahima Hamlaoui
- UMR Molécules de Communication et Adaptation des Micro-organismes, Muséum d'Histoire Naturelle de Paris, Paris, France
| | - Emilie Lance
- UMR Molécules de Communication et Adaptation des Micro-organismes, Muséum d'Histoire Naturelle de Paris, Paris, France
- UMR Stress environnementaux et biosurveillance des milieux aquatiques, Université de Reims Champagne-Ardenne, Reims, France
| | - Benjamin Marie
- UMR Molécules de Communication et Adaptation des Micro-organismes, Muséum d'Histoire Naturelle de Paris, Paris, France
| | - Cécile Bernard
- UMR Molécules de Communication et Adaptation des Micro-organismes, Muséum d'Histoire Naturelle de Paris, Paris, France
| | | | - Catherine Quiblier
- UMR Molécules de Communication et Adaptation des Micro-organismes, Muséum d'Histoire Naturelle de Paris, Paris, France
- Université Paris Cité, Paris, France
| | - Jean-François Humbert
- Centre Île-de-France-Versailles-Grignon, Institut National de Recherche pour l'Agriculture l'Alimentation et l'Environnement, Paris, France.
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Heavy Metals Exacerbate the Effect of Temperature on the Growth of Chlorella sp.: Implications on Algal Blooms and Management. Processes (Basel) 2022. [DOI: 10.3390/pr10122638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
With the accelerated urbanization and rapid development of the industrial and agricultural sectors, concern about the pollution of water environments is becoming more widespread. Algal blooms of varying sizes are becoming increasingly frequent in lakes and reservoirs; temperatures, nutrients, heavy metals, and dissolved oxygen are the factors that influence algal bloom occurrence. However, knowledge of the combined effect of heavy metals and temperature on algal growth remains limited. Thus, this study investigated how specific concentrations of heavy metals affect algal growth at different temperatures; to this end, two heavy metals were used (0.01 mg/L Pb2+ and 0.05 mg/L Cr6+) at three incubation temperatures (15, 25, and 30 °C) with the alga Chlorella sp. A higher incubation temperature contributed to a rise in soluble proteins, which promoted algal growth. The density of algal cells increased with temperature, and catalase (CAT) decreased with increasing temperature. Chlorella sp. growth and catalase activity were optimal at 30 °C (algal cell density: 1.46 × 107 cell/L; CAT activity: 29.98 gprot/L). Pb2+ and Cr6+ significantly promoted Chlorella sp. growth during incubation at 25 and 30 °C, respectively. At specific temperatures, 0.01 mg/L Pb2+ and 0.05 mg/L Cr6+ promoted the production of soluble proteins and, hence, the growth of Chlorella sp. The results provide a useful background for the mitigation and prevention of algal blooms.
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