Journal of Marine Science and Engineering

Research

14 pages, 3930 KiB

Open AccessArticle

Effects of UVR on Photosynthesis in Sargassum horneri (Turner) C. Agardh Adapted to Different Nitrogen Levels

by Zhiguang Xu, Xiaotong Jiang, Baoqi Li, Zhengzheng Lv, Hongyan Wu, Shasha Zang, Fang Yan and Menglin Bao

J. Mar. Sci. Eng. 2023, 11(3), 498; https://doi.org/10.3390/jmse11030498 - 25 Feb 2023

Viewed by 1039

Abstract

In recent years, golden tides caused by drifting Sargassum horneri (Turner) C. Agardh have caused serious ecological disasters in coastal areas of China. Eutrophication is an important cause of the formation of the golden tide. Additionally, the drifting population on the surface of [...] Read more.

In recent years, golden tides caused by drifting Sargassum horneri (Turner) C. Agardh have caused serious ecological disasters in coastal areas of China. Eutrophication is an important cause of the formation of the golden tide. Additionally, the drifting population on the surface of the ocean is exposed to more ultraviolet radiation (UVR) than the attached population on the sea floor. In this study, the thalli of S. horneri were cultivated under two levels of nitrogen (LN: natural seawater, in which the concentration of NO₃⁻-N was 1 µmol L⁻¹; HN: NO₃⁻-enriched seawater, in which the concentration of NO₃⁻-N was 200 μmol L⁻¹) for 6 days with low photosynthetically active radiation (PAR), and then exposed to three levels of radiation (P: photosynthetically active radiation (PAR), 400–700 nm; PA: PAR + UVA, 320–700 nm; PAB: PAR + UVA + UVB, 280–700 nm) under each level of nitrogen for 2 h to investigate the effects of high UVR and nitrogen on photosynthesis. The results showed that the high level of N (HN) only enhanced the synthesis of pigments after 6 days of pre-cultivation under low PAR. After 2 h of high UVR exposure, high P, PA, and PB decreased the maximum photochemical quantum yield (F_v/F_m) and increased non-photochemical quenching (NPQ) in S. horneri regardless of the N level, and PAB significantly decreased F_v/F_m compared to PA under the LN condition alone. Under the LN condition, compared to the P group, PA and PAB significantly promoted the synthesis of carotenoids. Under the HN condition, compared to the P group, PAB increased the absorbed flux by active RCs (ABS/RC) and dissipated the energy flux by active RCs (DI₀/RC) in S. horneri alone. Furthermore, HN increased F_v/F_m, ABS/RC, and DI₀/RC more in S. horneri with PAB in comparison to those in the LN and PAB group. However, no significant differences in these parameters were observed between the LN and HN conditions under the same UVR treatments. These results demonstrate that drifting S. horneri on the surface of seawater could be inhibited by the high P; however, S. horneri living in eutrophic high-nitrogen seawater may have a stronger ability to resist high UVR damage, especially with regard to PAB radiation, which may be one of the reasons for the formation of golden tides in coastal seawater. Full article

(This article belongs to the Special Issue New Insights in the Study of Harmful Algal Bloom)

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16 pages, 4481 KiB

Open AccessArticle

Epizoans on Floating Golden Tide Macroalgae in the Southern Yellow Sea

by Jing Xia, Chongxiang Li, Yiyuan Tang, Ji Li, Tingjian Wu, Jinlin Liu and Jianheng Zhang

J. Mar. Sci. Eng. 2023, 11(3), 479; https://doi.org/10.3390/jmse11030479 - 23 Feb 2023

Viewed by 1155

Abstract

Golden tide macroalgae have been accumulating in the Southern Yellow Sea (SYS) for several years, causing serious damage to local coastal economy and ecosystems. However, little is known about the environmental and ecological significance of the epizoans drifting on the floating macroalgae. In [...] Read more.

Golden tide macroalgae have been accumulating in the Southern Yellow Sea (SYS) for several years, causing serious damage to local coastal economy and ecosystems. However, little is known about the environmental and ecological significance of the epizoans drifting on the floating macroalgae. In this study, floating macroalgae collected from four stations were identified as Sargassum horneri. Furthermore, morphological and molecular (based on the Cytochrome C Oxidase Subunit I, COI) identification revealed that the 28 epizoans on the macroalgae consisted of four crustacean (Ampithoe lacertosa, Idotea metallica, Apohyale sp., and Peramphithoe tea). Apohyale sp. and P. tea were found at all stations, while A. lacertosa is found at only one station. The weight range of Apohyale sp., P. tea, I. metallica, and A. lacertosa is 0.0037~0.0420 g, 0.0057~0.0304 g, 0.0222~0.6592 g, and 0.0047 g, respectively. The specific roles of these epizoans in the golden tide in SYS deserve further study. Our results provide a reference for future studies of invasive macroalgae and epizoans. Full article

(This article belongs to the Special Issue New Insights in the Study of Harmful Algal Bloom)

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11 pages, 1236 KiB

Open AccessArticle

Investigating the Role of Terminal Stolon of Marine Invasive Green Macroalga Caulerpa taxifolia in the Removal of Inorganic Nitrogen from Seawater

by Bingxin Huang, Zhan Wang, Yue Chu and Lanping Ding

J. Mar. Sci. Eng. 2023, 11(1), 43; https://doi.org/10.3390/jmse11010043 - 28 Dec 2022

Viewed by 967

Abstract

The marine benthic green macroalga Caulerpa taxifolia is an invasive seaweed found in Europe, America, and Australia, and it forms into huge algal meadows on shallow seafloors with its stolon and rhizoid systems. It has bloomed along the coast of the South China Sea, [...] Read more.

The marine benthic green macroalga Caulerpa taxifolia is an invasive seaweed found in Europe, America, and Australia, and it forms into huge algal meadows on shallow seafloors with its stolon and rhizoid systems. It has bloomed along the coast of the South China Sea, causing serious environmental problems. However, its ecological impact has not been well studied. Therefore, this study investigated the changes in concentration of NH₄-N and NO₂-N in artificial seawater in which C. taxifolia was cultivated under laboratory conditions during the circadian rhythm. Results showed that concentrations of NH₄-N and NO₂-N decreased with the increase in culture time during the circadian rhythm. In 24 h, the NH₄-N-removal efficiency increased during the light period, and the maximum reached 71.4%; that of NO₂-N increased with time extension in the dark period, and the maximum reached 9.2%. The absorption of NH₄-N and NO₂-N by terminal stolon of C. taxifolia was different. NH₄-N was absorbed more preferentially than NO₂-N. However, there was no obvious correlation between NH₄-N and NO₂-N absorption. Therefore, the terminal stolon of C. taxifolia can be used to clean up inorganic nitrogen, and showed great application potential in the remediation of eutrophic waters as the algal-bacterial symbiotic system could facilitate NO₂-N removal. Full article

(This article belongs to the Special Issue New Insights in the Study of Harmful Algal Bloom)

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13 pages, 3727 KiB

Open AccessArticle

Effects of Global Warming on the Growth and Proliferation of Attached Sargassum horneri in the Aquaculture Area near Gouqi Island, China

by Tingjian Wu, Lihua Xia, Minmin Zhuang, Jiayu Pan, Jinlin Liu, Wei Dai, Zitao Zhao, Meijing Zhang, Xiyu Shen, Peimin He, Jianheng Zhang and Yutao Qin

J. Mar. Sci. Eng. 2023, 11(1), 9; https://doi.org/10.3390/jmse11010009 - 21 Dec 2022

Cited by 3 | Viewed by 1794

Abstract

With global warming, in recent years, golden tides have frequently occurred off the coasts of China. Sargassum horneri, which attach to aquaculture rafts, can float and form small-scale golden tides after falling off. Temperature will affect the growth and reproduction of algae. [...] Read more.

With global warming, in recent years, golden tides have frequently occurred off the coasts of China. Sargassum horneri, which attach to aquaculture rafts, can float and form small-scale golden tides after falling off. Temperature will affect the growth and reproduction of algae. In order to explore whether the temperature is the potential influence factor of the golden tide outbreak, in this study, the effects of global warming on the growth and proliferation of S. horneri in the mussel aquaculture area of Gouqi Island will be discussed. Samples of the macroalgae were collected monthly from August 2021 to July 2022 at various stages of its life cycle, and the relationship between algal growth and temperature was analyzed based on the concept of effective accumulated temperature, combined with the parameters of sea surface temperature, photosynthetic rate, growth rate, and growth cycle. Based on the continuous temperature variation observed, the growth cycle could be divided into five stages: the decreasing temperature period (October to November), the low-temperature adaptation period (December), the second suitable low-temperature period (January to February), and the high-temperature decay period (February to May). The effective accumulated temperature stored by S. horneri from 2021 to 2022 was 2772.4 °C·d; compared with previous studies, it decreased by about 800 °C·d. The winter temperature in 2022 was higher than the average temperature in the previous 5 years, allowing the macroalgae to enter the reproductive period in advance. This had a significant impact on the blooming time of golden tides and led to an earlier outbreak and extinction. Therefore, in the future, we can set up a monitoring system for the early warning of golden tides according to the change of SST in winter. Full article

(This article belongs to the Special Issue New Insights in the Study of Harmful Algal Bloom)

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16 pages, 2365 KiB

Open AccessArticle

Responses of Marine Diatom–Dinoflagellate Interspecific Competition to Different Phosphorus Sources

by Anglu Shen, Hongyue Liu, Quandong Xin, Qingjing Hu, Xinliang Wang and Jufa Chen

J. Mar. Sci. Eng. 2022, 10(12), 1972; https://doi.org/10.3390/jmse10121972 - 11 Dec 2022

Cited by 4 | Viewed by 1270

Abstract

Phosphorus (P) is an essential nutrient element of phytoplankton, as well as a limiting factor for phytoplankton growth. It controls the succession of blooms from diatoms to dinoflagellates, especially in the East China Sea (ECS), where the eutrophication is serious. Most studies have [...] Read more.

Phosphorus (P) is an essential nutrient element of phytoplankton, as well as a limiting factor for phytoplankton growth. It controls the succession of blooms from diatoms to dinoflagellates, especially in the East China Sea (ECS), where the eutrophication is serious. Most studies have only considered a single aspect of dissolved inorganic phosphorus (DIP) or dissolved organic phosphorus (DOP). In contrast, we investigated the growth interactions among the major bloom-forming marine diatom Skeletonema costatum and dinoflagellates Prorocentrum donghaiense and Karenia mikimotoi by using bi-algal cultures combined with DIP and DOP. Our results revealed that (1) P. donghaiense and K. mikimotoi have survival strategies that are superior to those of S. costatum in a bi-algal culture, whether under P-sufficient or P-deficient conditions, and (2) P. donghaiense has a slight competitive advantage over K. mikimotoi when P is sufficient, but the reverse is true when P is deficient. The difference in interspecific competition results at different P concentrations with DIP and DOP mainly arises from the variation in the utilization abilities of different species as regards different P sources, a finding which can also provide strong evidence for revealing the succession of diatoms and dinoflagellates blooms in the ECS. Full article

(This article belongs to the Special Issue New Insights in the Study of Harmful Algal Bloom)

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16 pages, 3625 KiB

Open AccessArticle

The Morphology, Genetic Diversity, and Distribution of Ulva meridionalis (Ulvaceae, Chlorophyta) in Chinese Seas

by Meijuan Hu, Shuang Zhao, Jinlin Liu, Yichao Tong, Zhangyi Xia, Jing Xia, Shuang Li, Yuqing Sun, Jiaxing Cao and Jianheng Zhang

J. Mar. Sci. Eng. 2022, 10(12), 1873; https://doi.org/10.3390/jmse10121873 - 03 Dec 2022

Cited by 2 | Viewed by 2937

Abstract

Green tides originate from the rapid growth of green macroalgae and their large accumulation. In the past few decades, the severity and frequency of green tides have increased and the range of their geographical distribution has widened. In recent years, Ulva meridionalis Horimoto [...] Read more.

Green tides originate from the rapid growth of green macroalgae and their large accumulation. In the past few decades, the severity and frequency of green tides have increased and the range of their geographical distribution has widened. In recent years, Ulva meridionalis Horimoto et Shimada has been reported in many countries. This species has stable morphological characteristics, and its length can reach 3 m in indoor cultures. Its cells contain pyrenoids, and the sporangium and gametangium of each cell contain 8 spores and 16 gametes, respectively, which confer a high proliferation potential. The phylogenetic tree constructed in this study showed that the Internal Transcribed Spacer sequence identified U. meridionalis with a high identification reliability, and the genetic relationship between U. meridionalis and Ulva pertusa in the ITS sequence was close. The haplotype network analysis clarified the relationship of the U. meridionalis samples collected from four different sea areas in China and indicated that they were closely related. Five haplotypes were identified: Hap_2 and Hap_1 were the most frequent, and they were also the haplotypes shared among the three groups. The degree of subspecies formation was not reached among these U. meridionalis samples collected from the Chinese seas. Up to 20 years ago, U. meridionalis had only been recorded in Japan. After 2011, it has been found to be widely distributed in the United States, China, French New Caledonia, French Polynesia, and Australia, where it proliferates. It has spread as a new kind of green tide-forming macroalga. The present study found that U. meridionalis is widely distributed in the Chinese seas; specifically, there have been small-scale blooms in the Bohai Sea, the Yellow Sea, and the South China Sea. Further investigations should focus on establishing whether U. meridionalis will cause large-scale green tide events in the future. Full article

(This article belongs to the Special Issue New Insights in the Study of Harmful Algal Bloom)

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18 pages, 5219 KiB

Open AccessArticle

Distribution and Identification of Ulva aragoensis (Ulvaceae, Chlorophyta), a Constituent Species of Green Tides in the Southern Yellow Sea, Based on Molecular Data

by Yichao Tong, Lihua Xia, Jinlin Liu, Shuang Zhao, Yuqing Sun, Tingjian Wu, Zhangyi Xia, Shuang Li, Jiaxing Cao and Jianheng Zhang

J. Mar. Sci. Eng. 2022, 10(11), 1767; https://doi.org/10.3390/jmse10111767 - 17 Nov 2022

Cited by 2 | Viewed by 1492

Abstract

Green tides are a serious global ecological disaster; the largest occur in the Southern Yellow Sea (SYS). Early-stage green tides in the SYS are composed of four species (Ulva prolifera, Ulva flexuosa, Ulva linza, and Ulva compressa). We [...] Read more.

Green tides are a serious global ecological disaster; the largest occur in the Southern Yellow Sea (SYS). Early-stage green tides in the SYS are composed of four species (Ulva prolifera, Ulva flexuosa, Ulva linza, and Ulva compressa). We found that U. aragoensis is a constituent species of green tides in the SYS based on molecular data. Furthermore, this study re-evaluated the proportion of U. aragoensis in green tides and found that it was more prevalent in micro-propagules cultured from surface seawater during an early-stage green tide in 2021. The internal transcribed spacers, tufA, 18S, rbcL, large subunit, psbA, and rps2-trnL gene sequences were compared; the tufA and rbcL gene sequences were the most suitable DNA barcodes for distinguishing U. aragoensis. A haplotype analysis of the sequences of floating U. aragoensis and its micro-propagules was performed to study the correlation between green tide macroalgae and micro-propagules; close haplotype similarities occurred between them. This study further clarified the species composition of SYS green tides and provided a reference for assessing the relationship between micro-propagules and green tide macroalgae. Full article

(This article belongs to the Special Issue New Insights in the Study of Harmful Algal Bloom)

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14 pages, 1786 KiB

Open AccessArticle

Increased Temperature and Nitrogen Enrichment Inhibit the Growth of the Golden Tide Blooming Macroalgae Sargassum horneri in the Yellow Sea, China

by Hailong Wu, Xuebing Li, Yanhong Liu, Chuchu Wang, Chenkai Ji and Juntian Xu

J. Mar. Sci. Eng. 2022, 10(11), 1692; https://doi.org/10.3390/jmse10111692 - 08 Nov 2022

Cited by 3 | Viewed by 1633

Abstract

The golden tide, a large biomass bloom of the brown macroalgae Sargassum horneri, occurs yearly in the Yellow Sea, where it causes enormous economic and ecologic losses. To investigate the response of S. horneri to global warming and eutrophication, S. horneri was [...] Read more.

The golden tide, a large biomass bloom of the brown macroalgae Sargassum horneri, occurs yearly in the Yellow Sea, where it causes enormous economic and ecologic losses. To investigate the response of S. horneri to global warming and eutrophication, S. horneri was cultured under six conditions of varying temperature combinations (20 and 24 °C) and nitrogen levels (5, 30, and 300 μM). The growth, photosynthetic performance, pigment content, and contents of soluble protein were assessed. The growth of S. horneri followed an increasing trend with increasing N concentration at ambient temperature. Elevated temperatures had an inhibitory effect on growth and photosynthesis in S. horneri, which was further enhanced by eutrophication. This suggests that in the globally warming environment of the future, eutrophication may reduce the frequency and scale of gold tide outbreaks during the hot season. Full article

(This article belongs to the Special Issue New Insights in the Study of Harmful Algal Bloom)

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17 pages, 2614 KiB

Open AccessArticle

Antimicrobial Effect of Carbon Nanodots–ZnO Nanocomposite Synthesized Using Sargassum horneri

by Kyung Woo Kim, Dawoon Chung, Seung-Hyun Jung, Yong Min Kwon, Jawoon Young Hwan Kim and Kyunghwa Baek

J. Mar. Sci. Eng. 2022, 10(10), 1546; https://doi.org/10.3390/jmse10101546 - 20 Oct 2022

Cited by 1 | Viewed by 1447

Abstract

For several years, industrial damages caused by massive blooming and drifting of Sargassum horneri (S. horneri) called “golden tides” seaweeds have been continuously reported in Korea. National efforts have been made to produce useful cases of application by using the troublesome [...] Read more.

For several years, industrial damages caused by massive blooming and drifting of Sargassum horneri (S. horneri) called “golden tides” seaweeds have been continuously reported in Korea. National efforts have been made to produce useful cases of application by using the troublesome S. horneri. As a part of that, a CNDs–ZnO nanocomposite with antibacterial and antifungal properties was synthesized through a simple hydrothermal reaction using S. horneri, and the results were verified in this paper. The antibacterial and antifungal activities were mainly determined by the disk diffusion test against five bacterial and fungal strains, respectively. Of note, the inhibitory effect of the CNDs–ZnO on the growth of both Gram-positive (Bacillus cereus and Staphylococcus aureus) and Gram-negative (Escherichia coli, Salmonella typhimurium, and Vibrio alginolyticus) bacteria was highly effective. Moreover, the nanocomposite showed low toxicity compared to chlorine bleach. In addition, the CNDs–ZnO showed antifungal activities against both yeast (Saccharomyces cerevisiae and Rhodotorula mucilaginosa) and mold (Aspergillus flavus, Aspergillus niger, and Aspergillus terreus). This work showed the potential usability in antimicrobial application based on poor marine brown alga considered as useless in Korea. Through this paper, it seems that sufficient utility and possibility can be expected upon various unappreciated and uninterested marine species. Full article

(This article belongs to the Special Issue New Insights in the Study of Harmful Algal Bloom)

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