Research

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9 pages, 721 KiB

Open AccessCommunication

Insights into Stress-Induced Death Processes during Aging in the Marine Bloom-Forming Dinoflagellate Karenia brevis

by Yida Gao and Deana L. Erdner

J. Mar. Sci. Eng. 2022, 10(12), 1993; https://doi.org/10.3390/jmse10121993 - 14 Dec 2022

Cited by 1 | Viewed by 923

Harmful algal blooms (HABs) globally affect marine ecosystems and human health. Significant attention has been paid to understanding the initiation processes of HABs, while much less is known of the mechanisms causing cell demise and bloom decline. Recent evidence reveals that programmed cell [...] Read more.

Harmful algal blooms (HABs) globally affect marine ecosystems and human health. Significant attention has been paid to understanding the initiation processes of HABs, while much less is known of the mechanisms causing cell demise and bloom decline. Recent evidence reveals that programmed cell death (PCD) can be a possible pathway for HAB termination. However, it is still not clear how PCD expression varies with the growth of marine phytoplankton. In order to characterize how susceptibility to stress-induced cell death changes with the growth of marine harmful algae, we examined the prevalence of PCD markers during 48 h after the addition of H₂O₂ in dinoflagellate Karenia brevis cultures at the early-log, mid-log and stationary phase. The results show that acute susceptibility to cell death (before time 0.5 h) increased as cultures aged, reflecting a chronological decrease in stress acclimation abilities. However, the youngest cultures showed strong PCD expression and the fastest overall rate of cell loss within the first 24 h, hypothesized to result from the cell-density-dependent H₂O₂ detoxifying process. This research highlights the existence of PCD in HAB species and that aging marine phytoplankton are more susceptible to exogenous stress, which agrees with previous observations of significant PCD during bloom decline. Full article

(This article belongs to the Special Issue Marine Harmful Algae)

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16 pages, 2661 KiB

Open AccessArticle

Palytoxin-Analogues Accumulation in Natural Mussel Banks during an Ostreopsis cf. ovata Bloom

by Stefano Accoroni, Marika Ubaldi, Simone Bacchiocchi, Francesca Neri, Melania Siracusa, Maria Giovanna Buonomo, Alessandra Campanelli and Cecilia Totti

J. Mar. Sci. Eng. 2022, 10(10), 1402; https://doi.org/10.3390/jmse10101402 - 01 Oct 2022

Cited by 8 | Viewed by 1514

Abstract

Intense blooms of the toxic dinoflagellate Ostreopsis producing palytoxin (PlTX) analogs, mainly ovatoxins (OVTXs), have been a recurrent phenomenon along several Mediterranean coasts. Although there is evidence of seafood contamination by these toxins, the dynamics of their bioaccumulation during Ostreopsis blooms is not [...] Read more.

Intense blooms of the toxic dinoflagellate Ostreopsis producing palytoxin (PlTX) analogs, mainly ovatoxins (OVTXs), have been a recurrent phenomenon along several Mediterranean coasts. Although there is evidence of seafood contamination by these toxins, the dynamics of their bioaccumulation during Ostreopsis blooms is not yet clear. Toxin concentrations in wild mussels at two sites in the Conero Riviera, along the northern Adriatic Sea (Portonovo and Passetto), were analyzed from August to October 2021, throughout an Ostreopsis cf. ovata bloom, to investigate their relationships with the bloom pattern and abundances. Contaminated mussels showed the typical toxin profile dominated by OVTX-a and -b, with levels lower than the threshold considered unsafe for human consumption (30 µg PlTX-equivalent kg⁻¹ soft tissue). The toxin content reached 36.4 µg PlTX kg⁻¹ soft tissue only in a single sampling date. A clear correlation between the bioaccumulation of OVTXs in mussels and the abundance of Ostreopsis was observed. Our results highlighted, however, that bioaccumulation in the mussels is not affected merely by the abundance of toxic microalgae, since higher toxin levels were recorded at Portonovo, where the cell abundances were lower than at Passetto. The results from this study indicate that the Italian guidelines for the management of Ostreopsis blooms in bathing waters are also useful in managing the risks of human intoxication through ingestion, as mussel contamination was detected only during the alert phase (10,000–30,000 cells L⁻¹). Full article

(This article belongs to the Special Issue Marine Harmful Algae)

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19 pages, 3349 KiB

Open AccessArticle

Effects of Algal Utilization of Dissolved Organic Phosphorus by Microcystis Aeruginosa on Its Adaptation Capability to Ambient Ultraviolet Radiation

by Lingxiao Ren, Jing Huang, Huagang Zhu, Wei Jiang, Haoyu Wu, Yuyang Pan, Yinghui Mao, Minghan Luo and Taeseop Jeong

J. Mar. Sci. Eng. 2022, 10(9), 1257; https://doi.org/10.3390/jmse10091257 - 06 Sep 2022

Cited by 1 | Viewed by 1410

Abstract

Phosphorus (P) plays an important role in eutrophication and algal adaptation to environmental stresses; therefore, a better understanding of the impact of P is essential to control cyanobacterial bloom. In this study, Microcystis aeruginosa is treated with 5 h of ambient irradiation in [...] Read more.

Phosphorus (P) plays an important role in eutrophication and algal adaptation to environmental stresses; therefore, a better understanding of the impact of P is essential to control cyanobacterial bloom. In this study, Microcystis aeruginosa is treated with 5 h of ambient irradiation in the culture medium with different availabilities of dissolved organic P (DOP) and dissolved organic matter (DOM) to explore algal physiological responses. Compared to photosynthetically active radiation (PAR), ambient UV-A and UV-B radiation exerted oxidative stresses and has inhibitive effects on the growth and photosynthesis of M. aeruginosa. However, M. aeruginosa had a strong adaptation capability, and the negative effects of UV radiation can be alleviated with DOM addition in the DOP-rich medium. The adaptation of M. aeruginosa to UV radiation in the DOP-rich waters can be mainly achieved through hydrolysis of DOP and metabolism of dissolved inorganic P (DIP), and the DOP utilization behaviors of M. aeruginosa might greatly affect algal UV adaptation capability. In the DOP-rich medium without DOM, the great inactivation of algal alkaline phosphatase (APase) after UV radiation could result in worse affinity for DOP, slower DOP uptake and lower cellular P quota. Consequently, the P demand of M. aeruginosa could not be satisfied for UV adaptation processes, including decreasing UV-induced damages and promoting self-repair. However, DOM could act as an antioxidant and significantly decrease APase inactivation of UV-radiated M. aeruginosa. In the DOP-rich medium with DOM, DOP utilization by M.aeruginosa in the UV-A and UV-B treatments is promoted and algal demand for P is satisfied for its adaptation, such as enhanced production of photosynthetic pigments, increased superoxide dismutase (SOD) activity, recovery of photosynthetic efficiency, etc. Overall, our findings indicate the close relationship between algal DOP utilization and the adaptation to ambient UV radiation of typical cyanobacteria in DIP-limited and DOP-enriched natural waters. Full article

(This article belongs to the Special Issue Marine Harmful Algae)

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20 pages, 2658 KiB

Open AccessArticle

Effects of Salinity on Growth and In Vitro Ichthyotoxicity of Three Strains of Karenia mikimotoi

by Winnie Lam, Emily Man-Shan Cheung, Nora Fung-Yee Tam, Thomas Chun-Hung Lee, Celia Sze-Nga Kwok, Kaze King-Yip Lai, Steven Jingliang Xu and Fred Wang-Fat Lee

J. Mar. Sci. Eng. 2022, 10(9), 1236; https://doi.org/10.3390/jmse10091236 - 03 Sep 2022

Cited by 2 | Viewed by 1957

Abstract

Karenia mikimotoi is one of the most damaging ichthyotoxic dinoflagellate species commonly found in China. However, its growth and ichthyotoxicity responses to salinity changes are still largely unknown. In this study, the growth and ichthyotoxicity of three K. mikimotoi strains, Hong Kong strain [...] Read more.

Karenia mikimotoi is one of the most damaging ichthyotoxic dinoflagellate species commonly found in China. However, its growth and ichthyotoxicity responses to salinity changes are still largely unknown. In this study, the growth and ichthyotoxicity of three K. mikimotoi strains, Hong Kong strain KMHK, Japanese strain NIES2411 and New Zealand strain CAWD133, under different salinities (25 to 35 ppt), initial algal densities (5 to 40 thousand cells) and growth phases were investigated. Results indicated that the optimum salinity for all three strains was 30 ppt. The Japanese strain achieved the highest maximum cell densities (cells mL⁻¹) and the New Zealand strain achieved the highest specific growth rate. The Hong Kong and New Zealand strains could not tolerate the low salinity at 25 ppt and the algal cells burst after 3 days of exposure. The average cell widths of all three algal strains in 35 ppt salinity were significantly larger than that in 30 ppt. The acute toxicity test performed on Oncorhynchus mykiss gill cell line RTgill-W1 revealed that the median lethal times for KMHK and NIES2411 were 66.9 and 31.3 min, respectively, and their ichthyotoxicity was significantly affected by algal cell density and growth phase. Nevertheless, CAWD133 did not pose any ichthyotoxicity. The gill cell viability levels at 30 min were reduced from 96 to 61% and 95 to 39% for KMHK and NIES2411, respectively, when the algal cell density increased from 5 × 10³ to 4 × 10⁴ algal cells mL⁻¹. Both KMHK and NIES2411 at stationary phase also had higher toxicity than at log phase, with a 27% reduction of gill cell viability, and exerted higher toxicity to the gill cells under extremely low (28 ppt) or high (35 ppt) salinity. These findings demonstrated that the growth–ichthyotoxicity response of Karenia mikimotoi to salinity was not only strain-specific but also depended on its density and growth phase. Study on the effects of salinity on the growth and toxicity of K. mikimotoi is greatly limited. Results from the present study provide valuable insight on the growth and toxicity of different K. mikimotoi strains, which is important in understanding their occurrence of algal bloom and fish-killing action. Full article

(This article belongs to the Special Issue Marine Harmful Algae)

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10 pages, 2098 KiB

Open AccessCommunication

Evaluation of a Causative Species of Harmful Algal Blooming, Prorocentrum triestinum, as a Sustainable Source of Biosorption on Cadmium

by Steven Jing-Liang Xu, Kam-Chau Wu, Winnie Lam and Fred Wang-Fat Lee

J. Mar. Sci. Eng. 2022, 10(6), 837; https://doi.org/10.3390/jmse10060837 - 20 Jun 2022

Viewed by 1281

Abstract

Biosorption is an effective method for removing heavy metal ions from wastewater. In the current study, the biosorption capacity of a microalgae Prorocentrum triestinum strain AD1 was investigated for cadmium removal. The efficient biomass concentration was found to be 5 g/L. Based on [...] Read more.

Biosorption is an effective method for removing heavy metal ions from wastewater. In the current study, the biosorption capacity of a microalgae Prorocentrum triestinum strain AD1 was investigated for cadmium removal. The efficient biomass concentration was found to be 5 g/L. Based on the Langmuir adsorption model, the maximum adsorption capacity (q_max) value of cadmium removal was found to be 0.0196 mmol/g. The investigation results of the AD1 biosorption kinetics showed that the effective contact time on biosorption was 3 h, and the adsorption kinetics fitted well with the pseudo-second-order model. The optimum pH of biosorption was found to be 5. On the other hand, HCl could act as an efficient desorbent for cadmium recovery from AD1, with an optimum concentration of 0.01 M. These results suggest that the biomass of P. triestinum has great potential for the removal of cadmium from wastewater as an efficient biosorbent. Full article

(This article belongs to the Special Issue Marine Harmful Algae)

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18 pages, 2820 KiB

Open AccessArticle

Towards the Prediction of Favourable Conditions for the Harmful Algal Bloom Onset of Ostreopsis ovata in the Ligurian Sea Based on Satellite and Model Data

by Chiara Lapucci, Fabio Maselli, Graziella Chini Zittelli, Giulio Betti, Valentina Vannucchi, Massimo Perna, Stefano Taddei, Bernardo Gozzini, Alberto Ortolani and Carlo Brandini

J. Mar. Sci. Eng. 2022, 10(4), 461; https://doi.org/10.3390/jmse10040461 - 24 Mar 2022

Cited by 2 | Viewed by 1995

Abstract

In recent years, the occurrence of Ostreopsis ovata (O. ovata) Harmful Algal Blooms (HAB) has increased in the coasts of the Ligurian Sea, causing problems to the marine environment and human health. Favourable conditions for O. ovata bloom are triggered by [...] Read more.

In recent years, the occurrence of Ostreopsis ovata (O. ovata) Harmful Algal Blooms (HAB) has increased in the coasts of the Ligurian Sea, causing problems to the marine environment and human health. Favourable conditions for O. ovata bloom are triggered by many drivers, many of which are still under investigation, but we hypothesize that this phenomenon can be simulated using a reduced number of major meteo-marine factors, namely water temperature and remixing. Satellite and model data obtained and derived from Copernicus service, namely Sea Surface Temperature (SST) and Significant Wave Height (SWH), were therefore investigated as possible proxies of these local factors. A simplified conceptual model, built on such proxies, was developed and applied to yield a synthetic indicator informative on O. ovata abundance. The model was tested in two study areas in the Ligurian Sea, Marina di Pisa and Marina di Massa in Tuscany, Italy. The results obtained show that the synthetic indicator is able to account for about 35% of the temporal variability of O. ovata bloom occurrence in the two study areas. Full article

(This article belongs to the Special Issue Marine Harmful Algae)

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17 pages, 4598 KiB

Open AccessArticle

Zooplankton Population and Community Structure Changes in Response to a Harmful Algal Bloom Caused by Prorocentrum donghaiense in the East China Sea

by Anglu Shen, Wenwen Chen, Yongjiu Xu and Kin-Chung Ho

J. Mar. Sci. Eng. 2022, 10(2), 291; https://doi.org/10.3390/jmse10020291 - 19 Feb 2022

Cited by 6 | Viewed by 1936

Abstract

Blooms of the dinoflagellate Prorocentrum donghaiense have had adverse impacts on marine ecosystems. However, ecological details, particularly the impacts and processes of the P. donghaiense bloom on the zooplankton community structure are poorly known. We investigated the changes of zooplankton communities in situ [...] Read more.

Blooms of the dinoflagellate Prorocentrum donghaiense have had adverse impacts on marine ecosystems. However, ecological details, particularly the impacts and processes of the P. donghaiense bloom on the zooplankton community structure are poorly known. We investigated the changes of zooplankton communities in situ within the whole process of a P. donghaiense bloom in the coastal waters in southern Zhejiang Province, China, in May 2016. Results showed that ecological changes during the blooms of P. donghaiense could be divided into three major phases, namely the growth, maintenance, and dissipation phases with regard to the cell abundance of P. donghaiense by bottle sampling of plankton. A total of 42 species of zooplankton were identified. The average abundance and species number of zooplankton in the growth phase were significantly higher than those in the maintenance and dissipation phases. It is shown that the top-two highest proportions of zooplankton in the growth phase were small jellyfishes and copepods, while small jellyfishes and chaetognaths, and copepoda larvae and chaetognaths were the top-two highest in the maintenance and dissipation phases respectively. However, the values of biodiversity index have no statistically significant differences between the three phases. The present results suggested that P. donghaiense bloom produced significant negative impacts on the abundance and species composition of zooplankton with particular reference to copepods. Full article

(This article belongs to the Special Issue Marine Harmful Algae)

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Review

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28 pages, 12911 KiB

Open AccessReview

Spatial Temporal Expansion of Harmful Algal Blooms in Chile: A Review of 65 Years Records

by Camila Barría, Piera Vásquez-Calderón, Catalina Lizama, Pablo Herrera, Anahi Canto, Pablo Conejeros, Orietta Beltrami, Benjamín A. Suárez-Isla, Daniel Carrasco, Ignacio Rubilar, Leonardo Guzmán, L. René Durán and Doris Oliva

J. Mar. Sci. Eng. 2022, 10(12), 1868; https://doi.org/10.3390/jmse10121868 - 02 Dec 2022

Cited by 4 | Viewed by 1931

Abstract

Harmful Algal Blooms (HABs) have been classified depending on the causative organism and its impacts: non-toxic HAB (microalgae capable of affecting tourism and causing oxygen deficiency, which generates mortality of marine organisms), toxic HAB (microalgae capable of transferring toxins to the food chain), [...] Read more.

Harmful Algal Blooms (HABs) have been classified depending on the causative organism and its impacts: non-toxic HAB (microalgae capable of affecting tourism and causing oxygen deficiency, which generates mortality of marine organisms), toxic HAB (microalgae capable of transferring toxins to the food chain), and ichthyotoxic HAB (microalgae capable of generating mechanical damage in fish). HABs represent a worldwide problem and have apparently increased in frequency, intensity, and geographic distribution at different latitudes. This review details the occurrence of HAB events in the Southeast Pacific, Chile, over a 65-year period, analysing two of the three types of HAB described: toxic and ichthyotoxic HABs. For this, we conducted a review from many different scientific sources and from the written press and social media, that have mentioned HAB events in the country. In Chile, the microalgae involved in HAB events are dinoflagellate (52%), diatoms (33%) and silicoflagellate (10%), with a total of 41 species and/or genera described in the literature. A total of 501 HAB events were recorded in Chile between 1956 and 2021, where 240 (47.9%), 238 (47.5%), 14 (2.7%), 8 (1.5%) and 1 (0.2%) event were caused by diatoms, dinoflagellate, silicoflagellate, raphidophycean and haptophyte, respectively. An apparent increase in the frequency of HAB events is observed since the first record in 1956, with a maximum of 46 events during the years 2017 and 2019. The highest incidence in fish is caused by the group of silicoflagellate, raphidophycean and haptophyte (23 events), where 10 events caused mortalities in salmon with an incidence rate of 43.4%. Unlike what is observed with diatoms and dinoflagellate, the events associated with these groups are less frequent, but hold a much higher salmon mortality rate. During the last 65 years, HAB’s geographic extent shows an apparent trend to increase south-to-north. However, the identification of events is closely linked to the areas where much of the country’s aquaculture is located and, therefore, it could be biased. In turn, it is observed that the apparent increase in HAB events could be associated with a greater monitoring effort after major events (e.g., after the 2016 HAB event). On the other hand, it is also recognized a lack of knowledge about harmful algae throughout the Chilean Humboldt Current system, particularly in the northern regions, such as Atacama and Coquimbo. Therefore, the total number of blooms that have occurred in fjords and channels, particularly those that have caused minor economic impacts for artisanal fishermen and the salmon and mussel farming sector, might be underestimated. Full article

(This article belongs to the Special Issue Marine Harmful Algae)

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