Editorial

4 pages, 199 KiB

Open AccessEditorial

by Bum Soo Park and Zhun Li

J. Mar. Sci. Eng. 2022, 10(1), 105; https://doi.org/10.3390/jmse10010105 - 14 Jan 2022

Cited by 1 | Viewed by 1869

The term “algae” refers to a large diversity of unrelated phylogenetic entities, ranging from picoplanktonic cells to macroalgal kelps [...] Full article

(This article belongs to the Special Issue Taxonomy and Ecology of Marine Algae)

Research

Jump to: Editorial, Review

10 pages, 3728 KiB

Open AccessArticle

Numerical Study on the Massive Outbreak of the Ulva prolifera Green Tides in the Southwestern Yellow Sea in 2021

by Bin Wang and Lei Wu

J. Mar. Sci. Eng. 2021, 9(11), 1167; https://doi.org/10.3390/jmse9111167 - 24 Oct 2021

Cited by 14 | Viewed by 2006

Abstract

The most massive outbreak on record of the Ulva prolifera green tides in the southwestern Yellow Sea occurred in summer of 2021. The environmental factors were investigated based on observations and simulations. The results suggested that the significantly enhanced discharge of the Changjiang [...] Read more.

The most massive outbreak on record of the Ulva prolifera green tides in the southwestern Yellow Sea occurred in summer of 2021. The environmental factors were investigated based on observations and simulations. The results suggested that the significantly enhanced discharge of the Changjiang River since winter 2020–2021 was crucial for the outbreak of the Ulva prolifera green tides in the southwestern Yellow Sea, which could significantly have contributed to the nutrient enrichment off the Subei coast. Additionally, the southerly wind stress anomaly during winter 2020–2021 favored the upwind transport of Changjiang water. Numerical experiments showed that the remaining winter freshwater coming from the Changjiang River, which persisted in the Subei coast’s upper layer until spring 2021, exceeded the long-term average value by 20%. We demonstrated that these large amount of nutrient inputs, as an effective supplement, were the reason the green tides sharply emerged as an extensive outbreak in 2021. The easterly wind anomaly during spring 2021 contributed to the landing of Ulva prolifera off the Lunan coast. Full article

(This article belongs to the Special Issue Taxonomy and Ecology of Marine Algae)

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14 pages, 3943 KiB

Open AccessArticle

Detection of the Benthic Dinoflagellates, Ostreopsis cf. ovata and Amphidinium massartii (Dinophyceae), Using Loop-Mediated Isothermal Amplification

by Eun Sun Lee, Jinik Hwang, Jun-Ho Hyung and Jaeyeon Park

J. Mar. Sci. Eng. 2021, 9(8), 885; https://doi.org/10.3390/jmse9080885 - 17 Aug 2021

Cited by 1 | Viewed by 1905

Abstract

For the in situ and sensitive detection of benthic dinoflagellates, we have established an integrated loop-mediated isothermal amplification (LAMP) assay based on Ostreopsis cf. ovata and Amphidinium massartii. To detect the two species, a set of species-specific primers was constructed between the [...] Read more.

For the in situ and sensitive detection of benthic dinoflagellates, we have established an integrated loop-mediated isothermal amplification (LAMP) assay based on Ostreopsis cf. ovata and Amphidinium massartii. To detect the two species, a set of species-specific primers was constructed between the ITS gene and D1–D6 LSU gene, and the reaction temperature, time, and buffer composition were optimized to establish this method. In addition, the specificity of the LAMP primers was verified both in strains established in the laboratory and in field samples collected from the Jeju coastal waters, Korea. With the LAMP assay, the analysing time was within 45 to 60 min, which may be shorter than that with the conventional PCR. The detection sensitivity of the LAMP assay for O. cf. ovata or A. massartii was comparable to other molecular assays (PCR and quantitative PCR (qPCR)) and microscopy examination. The detection limit of LAMP was 0.1 cell of O. cf. ovata and 1 cell of A. massartii. The optimized LAMP assay was successfully applied to detect O. cf. ovata and A. massartii in field samples. Thus, this study provides an effective method for detecting target benthic dinoflagellate species, and could be further implemented to monitor phytoplankton in field surveys as an altenative. Full article

(This article belongs to the Special Issue Taxonomy and Ecology of Marine Algae)

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12 pages, 4238 KiB

Open AccessArticle

Molecular and Morphological Characterization of Colaconema formosanum sp. nov. (Colaconemataceae, Rhodophyta)—A New Endophytic Filamentous Red Algal Species from Taiwan

by Meng-Chou Lee and Han-Yang Yeh

J. Mar. Sci. Eng. 2021, 9(8), 809; https://doi.org/10.3390/jmse9080809 - 27 Jul 2021

Cited by 6 | Viewed by 3029

Abstract

The genus Colaconema, containing endophytic algae associated with economically important macroalgae, is common around the world, but has rarely been reported in Taiwan. A new species, C. formosanum, was found attached to an economically important local macroalga, Sarcodia suae, in southern [...] Read more.

The genus Colaconema, containing endophytic algae associated with economically important macroalgae, is common around the world, but has rarely been reported in Taiwan. A new species, C. formosanum, was found attached to an economically important local macroalga, Sarcodia suae, in southern Taiwan. The new species was confirmed based on morphological observations and molecular analysis. Both the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (rbcL) and cytochrome c oxidase subunit I (COI-5P) genes showed high genetic variation between our sample and related species. Anatomical observations indicated that the new species presents asexual reproduction by monospores, cylindrical cells, irregularly branched filaments, a single pyrenoid, and single parietal plastids. Our research supports the taxonomic placement of C. formosanum within the genus Colaconema. This study presents the third record of the Colaconema genus in Taiwan. Full article

(This article belongs to the Special Issue Taxonomy and Ecology of Marine Algae)

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13 pages, 4234 KiB

Open AccessArticle

New Records of the Diatoms (Bacillariophyceae) from the Coastal Lagoons in Korea

by Daeryul Kwon, Mirye Park, Chang Soo Lee, Chaehong Park and Sang Deuk Lee

J. Mar. Sci. Eng. 2021, 9(7), 694; https://doi.org/10.3390/jmse9070694 - 24 Jun 2021

Cited by 5 | Viewed by 2389

Abstract

Lagoons are natural bodies of water that are isolated from the sea due to the development of a sand bar or spit. Each lagoon has distinct ecological characteristics, and these sites also serve as popular tourist attractions because they are common habitats for [...] Read more.

Lagoons are natural bodies of water that are isolated from the sea due to the development of a sand bar or spit. Each lagoon has distinct ecological characteristics, and these sites also serve as popular tourist attractions because they are common habitats for migratory birds and are characterized by beautiful natural scenery. Lagoons also have distinct ecological characteristics from those of their associated estuaries, and there are active research efforts to classify, qualify, and quantify the high biodiversity of lagoons. The lagoons in Korea are primarily distributed in the East Sea, and are represented by Hwajinpo, Yeongrangho, and Gyeongpoho. Here, we report the discovery of 11 unrecorded diatom species (Diploneis didyma, Mastogloia elliptica, Cosmioneis citriformis, Haslea crucigera, Pinnularia bertrandii, Pinnularia nodosa var. percapitata, Gyrosigma sinense, Gomphonema guaraniarum, Gomphonema italicum, Navicula freesei, Trybionella littoralis var. tergestina) among samples collected from the Hwajinpo, Hyangho, Maeho, Gapyeongri wetland, Cheonjinho, and Gyeongpoho lagoons in Korea during a survey from 2018–2020. We present the taxonomic characteristics, ecological information, habitat environmental conditions, and references for these 11 species. Full article

(This article belongs to the Special Issue Taxonomy and Ecology of Marine Algae)

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11 pages, 3278 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

First Report of the Marine Benthic Dinoflagellate Bysmatrum subsalsum from Korean Tidal Pools

by Joon Sang Park, Zhun Li, Hyun Jung Kim, Ki Hyun Kim, Kyun Woo Lee, Joo Yeon Youn, Kyeong Yoon Kwak and Hyeon Ho Shin

J. Mar. Sci. Eng. 2021, 9(6), 649; https://doi.org/10.3390/jmse9060649 - 12 Jun 2021

Cited by 2 | Viewed by 2514

Abstract

Dense patches were observed in the tidal pools of the southern area of Korea. To clarify the causative organisms, the cells were collected and their morphological features were examined using light and scanning electron microscopy (SEM). In addition, after establishing strains for the [...] Read more.

Dense patches were observed in the tidal pools of the southern area of Korea. To clarify the causative organisms, the cells were collected and their morphological features were examined using light and scanning electron microscopy (SEM). In addition, after establishing strains for the cells the molecular phylogeny was inferred with concatenated small subunit (SSU) and large subunit (LSU) rRNA sequences. The cells were characterized by a nucleus in the hypotheca, strong reticulations in thecal plates, the separation of plates 2a and 3a, the tear-shaped apical pore complex, an elongated rectangular 1a plate and the absence of the right sulcal list. The thecal plate formula was Po, X, 4′, 3a, 7″, 6c, 4S, 5′′′, 2′′′′. Based on these morphological features, the cells were identified as Bysmatrum subsalsum. In the culture, the spherical cysts of B. subsalsum without thecal plates were observed. Molecular phylogeny revealed two ribotypes of B. subsalsum are identified; The Korean isolates were nested within the ribotype B consisting of the isolates from China, Malaysia and the French Atlantic, whereas the ribotype A includes only the isolates from the Mediterranean Sea. In the phylogeny, B. subsalsum and B. austrafrum were grouped. This can be supported by the morphological similarity between the two species, indicating that the two species may be conspecific, however B. subsalsum may distinguish from B. austrafrum, because of differences in the types of eyespots reported in previous studies. These findings support the idea that there is cryptic diversity within B. subsalsum. Full article

(This article belongs to the Special Issue Taxonomy and Ecology of Marine Algae)

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18 pages, 4812 KiB

Open AccessArticle

Identification of New Sub-Fossil Diatoms Flora in the Sediments of Suncheonman Bay, Korea

by Mirye Park, Sang Deuk Lee, Hoil Lee, Jin-Young Lee, Daeryul Kwon and Jeong-Min Choi

J. Mar. Sci. Eng. 2021, 9(6), 591; https://doi.org/10.3390/jmse9060591 - 29 May 2021

Cited by 3 | Viewed by 2782

Abstract

Suncheonman Bay, Korea’s most representative estuary, is an invasive coastal wetland composed of 22.6 km² of tidal flats surrounded by the Yeosu and Goheung Peninsulas. In January 2006, this region was registered in the Ramsar Convention list in Korea, representing the first [...] Read more.

Suncheonman Bay, Korea’s most representative estuary, is an invasive coastal wetland composed of 22.6 km² of tidal flats surrounded by the Yeosu and Goheung Peninsulas. In January 2006, this region was registered in the Ramsar Convention list in Korea, representing the first registered wetland. Estuaries are generally known to have high species diversity. In particular, several studies have been conducted on planktonic and epipelic diatoms as primary producers. Suncheonman Bay has already been involved in many biological and geochemical studies, but fossil diatoms have not been evaluated. Therefore, we investigated fossil diatoms in Suncheonman Bay and introduced sub-fossil diatoms recorded in Korea. One sedimentary core has been extracted in 2018. We identified 87 diatom taxa from 52 genera in the SCW03 core sample. Of these, six species represent new records in Korea: Cymatonitzschia marina, Fallacia hodgeana, Navicula mannii, Metascolioneis tumida, Surirella recedens, and Thalassionema synedriforme. These six newly recorded diatom species were examined by light microscopy and scanning electron microscopy. The ecological habitats for all the investigated taxa are presented. Full article

(This article belongs to the Special Issue Taxonomy and Ecology of Marine Algae)

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17 pages, 2648 KiB

Open AccessArticle

Coagulant Plus Bacillus nitratireducens Fermentation Broth Technique Provides a Rapid Algicidal Effect of Toxic Red Tide Dinoflagellate

by Barathan Balaji Prasath, Ying Wang, Yuping Su, Wanning Zheng, Hong Lin and Hong Yang

J. Mar. Sci. Eng. 2021, 9(4), 395; https://doi.org/10.3390/jmse9040395 - 08 Apr 2021

Cited by 10 | Viewed by 2576

Abstract

When the toxic red tide alga Gymnodinium catenatum H.W. Graham accumulates in sediment through sexual reproduction, it provides the provenance of a periodic outbreak of red tide, a potential threat to the marine environment. In our study, the flocculation effects of four coagulants [...] Read more.

When the toxic red tide alga Gymnodinium catenatum H.W. Graham accumulates in sediment through sexual reproduction, it provides the provenance of a periodic outbreak of red tide, a potential threat to the marine environment. In our study, the flocculation effects of four coagulants were compared. Bacteria fermentation (Ba3) broth and coagulant were combined with Ba3 to reduce the vegetative cells of G. catenatum, inhibit the cystic germination in the sediment, and control the red tide outbreak. To promote a more efficient and environmentally friendly algae suppression method, we studied these four coagulants combined with algae suppression bacteria for their effect on G. catenatum. The results show that polyaluminum chloride (PAC) is more efficient than other coagulants when used alone because it had a more substantial inhibitory effect. Ba3 broth also had a beneficial removal effect on the vegetative cells of G. catenatum. The inhibition efficiency of 2-day fermentation liquid was higher than that of 1-day and 3-day fermentation liquids. When combined, the PAC and Ba3 broth produced a pronounced algae inhibition effect that effectively hindered the germination of algae cysts. We conclude that this combination provides a scientific reference for the prevention and control of marine red tide. Our results suggest that designing environmentally friendly methods for the management of harmful algae is quite feasible. Full article

(This article belongs to the Special Issue Taxonomy and Ecology of Marine Algae)

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10 pages, 1698 KiB

Open AccessFeature PaperArticle

Changes in Free-Living and Particle-Associated Bacterial Communities Depending on the Growth Phases of Marine Green Algae, Tetraselmis suecica

by Bum Soo Park, Won-Ji Choi, Ruoyu Guo, Hansol Kim and Jang-Seu Ki

J. Mar. Sci. Eng. 2021, 9(2), 171; https://doi.org/10.3390/jmse9020171 - 08 Feb 2021

Cited by 3 | Viewed by 2320

Abstract

Bacteria are remarkably associated with the growth of green algae Tetraselmis which are used as a feed source in aquaculture, but Tetraselmis-associated bacterial community is characterized insufficiently. Here, as a first step towards characterization of the associated bacteria, we investigated the community [...] Read more.

Bacteria are remarkably associated with the growth of green algae Tetraselmis which are used as a feed source in aquaculture, but Tetraselmis-associated bacterial community is characterized insufficiently. Here, as a first step towards characterization of the associated bacteria, we investigated the community composition of free-living (FLB) and particle-associated (PAB) bacteria in each growth phase (lag, exponential, stationary, and death) of Tetraselmis suecica P039 culture using pyrosequencing. The percentage of shared operational taxonomic units (OTUs) between FLB and PAB communities was substantially high (≥92.4%), but their bacterial community compositions were significantly (p = 0.05) different from each other. The PAB community was more variable than the FLB community depending on the growth phase of T. suecica. In the PAB community, the proportions of Marinobacter and Flavobacteriaceae were considerably varied in accordance with the cell number of T. suecica, but there was no clear variation in the FLB community composition. This suggests that the PAB community may have a stronger association with the algal growth than the FLB community. Interestingly, irrespective of the growth phase, Roseobacter clade and genus Muricauda were predominant in both FLB and PAB communities, indicating that bacterial communities in T. suecica culture may positively affect the algae growth and that they are potentially capable of enhancing the T. suecica growth. Full article

(This article belongs to the Special Issue Taxonomy and Ecology of Marine Algae)

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15 pages, 8640 KiB

Open AccessArticle

Morphology and Phylogeny of Scrippsiella precaria Montresor & Zingone (Thoracosphaerales, Dinophyceae) from Korean Coastal Waters

by Hyun Jung Kim, Zhun Li, Nam Seon Kang, Haifeng Gu, Daekyung Kim, Min Ho Seo, Sang Deuk Lee, Suk Min Yun, Seok-Jin Oh and Hyeon Ho Shin

J. Mar. Sci. Eng. 2021, 9(2), 154; https://doi.org/10.3390/jmse9020154 - 03 Feb 2021

Cited by 1 | Viewed by 3005

Abstract

The dinoflagellate genus Scrippsiella is a common member of phytoplankton and their cysts are also frequently reported in coastal sediments worldwide. However, the diversity of Scrippsiella in Korean waters has not been fully investigated. Here, several isolates of Scrippsiella precaria collected from Korean [...] Read more.

The dinoflagellate genus Scrippsiella is a common member of phytoplankton and their cysts are also frequently reported in coastal sediments worldwide. However, the diversity of Scrippsiella in Korean waters has not been fully investigated. Here, several isolates of Scrippsiella precaria collected from Korean waters and germinated from resting cysts were examined using light and scanning electron microscopy. The resting cysts were characterized by pointed calcareous spines and one or two red accumulation bodies, and the archeopyle was mesoepicystal, representing the loss of 2–4′ and 1–3a paraplates. Rounded resting cysts were found in culture, and an increase in spine length was observed until 8 days of development. Korean isolates of S. precaria had the plate formula of Po, X, 4′, 3a, 7″, 6C, 4S, 5‴, 2⁗. There were differences in the cell size and location of the red body between Korean isolates and previously described cells of S. precaria. In addition, the Korean isolates of S. precaria had two types of the 5″ plate that either contacted the 2a plate or not. Molecular phylogeny based on internal transcribed spacer (ITS) and large subunit (LSU) rDNA sequences revealed that the Korean isolates were nested within the subclade of PRE (S. precaria and related species) in the clade of Scrippsiella sensu lato, and that the PRE subclade had two ribotypes: ribotype 1 consisting of the isolates from Korea, China, and Australia, and ribotype 2 consisting of the isolates from Italy and Greece. Lineages between isolates of ribotype 1 were likely to be related to the dispersal by ocean currents and ballast waters from international shipping, and the two types of spine shapes and locations of the 5″ plates may be a distinct feature for ribotype 1. Full article

(This article belongs to the Special Issue Taxonomy and Ecology of Marine Algae)

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12 pages, 3792 KiB

Open AccessArticle

Laboratory Culture-Based Characterization of the Resting Stage Cells of the Brown-Tide-Causing Pelagophyte, Aureococcus anophagefferens

by Zhaopeng Ma, Zhangxi Hu, Yunyan Deng, Lixia Shang, Christophere J. Gobler and Ying Zhong Tang

J. Mar. Sci. Eng. 2020, 8(12), 1027; https://doi.org/10.3390/jmse8121027 - 16 Dec 2020

Cited by 5 | Viewed by 2540

Abstract

Life history (life cycle) plays a vital role in the ecology of some microalgae; however, the well-known brown-tide-causing pelagophyte Aureococcus anophagefferens has been barely investigated in this regard. Recently, based mainly on detections in marine sediments from China, we proved that this organism [...] Read more.

Life history (life cycle) plays a vital role in the ecology of some microalgae; however, the well-known brown-tide-causing pelagophyte Aureococcus anophagefferens has been barely investigated in this regard. Recently, based mainly on detections in marine sediments from China, we proved that this organism has a resting stage. We, therefore, conducted a follow-up study to characterize the resting stage cells (RSCs) of A. anophagefferens using the culture CCMP1984. The RSCs were spherical, larger than the vegetative cells, and smooth in cell surface and contained more aggregated plastid but more vacuolar space than vegetative cells. RSCs contained a conspicuous lipid-enriched red droplet. We found a 9.9-fold decrease in adenosine triphosphate (ATP) content from vegetative cells to RSCs, indicative of a "resting" or dormant physiological state. The RSCs stored for 3 months (at 4 °C in darkness) readily reverted back to vegetative growth within 20 days after being transferred to the conditions for routine culture maintenance. Our results indicate that the RSCs of A. anophagefferens are a dormant state that differs from vegetative cells morphologically and physiologically, and that RSCs likely enable the species to survive unfavorable conditions, seed annual blooms, and facilitate its cosmopolitan distribution that we recently documented. Full article

(This article belongs to the Special Issue Taxonomy and Ecology of Marine Algae)

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17 pages, 6227 KiB

Open AccessArticle

Multidisciplinary Analysis of Cystoseira sensu lato (SE Spain) Suggest a Complex Colonization of the Mediterranean

by Ana Belén Jódar-Pérez, Marc Terradas-Fernández, Federico López-Moya, Leticia Asensio-Berbegal and Luis Vicente López-Llorca

J. Mar. Sci. Eng. 2020, 8(12), 961; https://doi.org/10.3390/jmse8120961 - 25 Nov 2020

Cited by 6 | Viewed by 2594

Abstract

Cystoseira sensu lato (sl) are three genera widely recognized as bioindicators for their restricted habitat in a sub-coastal zone with low tolerance to pollution. Their ecological, morphological and taxonomic features are still little known due to their singular characteristics. We studied seven species [...] Read more.

Cystoseira sensu lato (sl) are three genera widely recognized as bioindicators for their restricted habitat in a sub-coastal zone with low tolerance to pollution. Their ecological, morphological and taxonomic features are still little known due to their singular characteristics. We studied seven species of Cystoseira sl spp. in Cabo de las Huertas (Alicante, SE Spain) and analyzed their distribution using Permutational Analysis of Variance (PERMANOVA) and Principal Component Ordination plots (PCO). A morphological cladogram has been constructed using fifteen phenotypic taxonomic relevant characters. We have also developed an optimized Cystoseira sl DNA extraction protocol. We have tested it to obtain amplicons from mt23S, tRNA-Lys and psbA genes. With these sequence data, we have built a phylogenetic supertree avoiding threatened Cystoseira sl species. Cartography and distribution analysis show that the response to hydrodynamism predicts perennial or seasonal behaviors. Morphological cladogram detects inter-specifical variability between our species and reference studies. Our DNA phylogenetic tree supports actual classification, including for the first-time Treptacantha sauvageauana and Treptacantha algeriensis species. These data support a complex distribution and speciation of Cystoseira sl spp. in the Mediterranean, perhaps involving Atlantic clades. The high ecological value of our area of study merits a future protection status as a Special Conservation Area. Full article

(This article belongs to the Special Issue Taxonomy and Ecology of Marine Algae)

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11 pages, 1546 KiB

Open AccessArticle

Isolation, Identification, and Biochemical Characteristics of a Cold-Tolerant Chlorella vulgaris KNUA007 Isolated from King George Island, Antarctica

by Seung-Woo Jo, Jeong-Mi Do, Nam Seon Kang, Jong Myong Park, Jae Hak Lee, Han Soon Kim, Ji Won Hong and Ho-Sung Yoon

J. Mar. Sci. Eng. 2020, 8(11), 935; https://doi.org/10.3390/jmse8110935 - 18 Nov 2020

Cited by 14 | Viewed by 4474

Abstract

A cold-tolerant unicellular green alga was isolated from a meltwater stream on King George Island, Antarctica. Morphological, molecular, and biochemical analyses revealed that the isolate belonged to the species Chlorella vulgaris. We tentatively named this algal strain C.vulgaris KNUA007 and investigated [...] Read more.

A cold-tolerant unicellular green alga was isolated from a meltwater stream on King George Island, Antarctica. Morphological, molecular, and biochemical analyses revealed that the isolate belonged to the species Chlorella vulgaris. We tentatively named this algal strain C.vulgaris KNUA007 and investigated its growth and lipid composition. We found that the strain was able to thrive in a wide range of temperatures, from 5 to 30 °C; however, it did not survive at 35 °C. Ultimate analysis confirmed high gross calorific values only at low temperatures (10 °C), with comparable values to land plants for biomass fuel. Gas chromatography/mass spectrometry analysis revealed that the isolate was rich in nutritionally important polyunsaturated fatty acids (PUFAs). The major fatty acid components were hexadecatrienoic acid (C16:3 ω3, 17.31%), linoleic acid (C18:2 ω6, 8.52%), and α-linolenic acid (C18:3 ω3, 43.35%) at 10 °C. The microalga was tolerant to low temperatures, making it an attractive candidate for the production of biochemicals under cold weather conditions. Therefore, this Antarctic microalga may have potential as an alternative to fish and/or plant oils as a source of omega-3 PUFA. The temperature tolerance and composition of C.vulgaris KNUA007 also make the isolate desirable for commercial applications in the pharmaceutical industry. Full article

(This article belongs to the Special Issue Taxonomy and Ecology of Marine Algae)

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18 pages, 3062 KiB

Open AccessArticle

Allelopathic Inhibition by the Bacteria Bacillus cereus BE23 on Growth and Photosynthesis of the Macroalga Ulva prolifera

by Naicheng Li, Jingyao Zhang, Xinyu Zhao, Pengbin Wang, Mengmeng Tong and Patricia M. Glibert

J. Mar. Sci. Eng. 2020, 8(9), 718; https://doi.org/10.3390/jmse8090718 - 16 Sep 2020

Cited by 2 | Viewed by 2685

Abstract

Bacteria-derived allelopathic effects on microalgae blooms have been studied with an aim to develop algicidal products that may have field applications. However, few such studies have been conducted on macroalgae. Therefore, a series of experiments was conducted to investigate the impacts of different [...] Read more.

Bacteria-derived allelopathic effects on microalgae blooms have been studied with an aim to develop algicidal products that may have field applications. However, few such studies have been conducted on macroalgae. Therefore, a series of experiments was conducted to investigate the impacts of different concentrations of cell-free filtrate of the bacteria Bacillus cereus BE23 on Ulva prolifera. Excessive reactive oxygen species (ROS) were produced when these cells were exposed to high concentrations of filtrate relative to f/2 medium. In such conditions, the antioxidative defense system of the macroalga was activated as shown by activities of the enzymes superoxide dismutase (SOD) and catalase (CAT) and upregulation of the associated genes upMnSOD and upCAT. High concentrations of filtrate also inhibited growth of U. prolifera, and reduced chlorophyll a and b, the photosynthetic efficiency (Fv/Fm), and the electron transport rate (rETR). Non-photochemical quenching (NPQ) was also inhibited, as evidenced by the downregulation of the photoprotective genes PsbS and LhcSR. Collectively, this evidence indicates that the alteration of energy dissipation caused excess cellular ROS accumulation that further induced oxidative damage on the photosynthesis apparatus of the D1 protein. The potential allelochemicals were further isolated by five steps of extraction and insolation (solid phase–liquid phase–open column–UPLC–preHPLC) and identified as N-phenethylacetamide, cyclo (L-Pro-L-Val), and cyclo (L-Pro-L-Pro) by HR-ESI-MS and NMR spectra. The diketopiperazines derivative, cyclo (L-Pro-L-Pro), exhibited the highest inhibition on U. prolifera and may be a good candidate as an algicidal product for green algae bloom control. Full article

(This article belongs to the Special Issue Taxonomy and Ecology of Marine Algae)

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21 pages, 12724 KiB

Open AccessReview

Plasticity and Multiplicity of Trophic Modes in the Dinoflagellate Karlodinium and Their Pertinence to Population Maintenance and Bloom Dynamics

by Huijiao Yang, Zhangxi Hu and Ying Zhong Tang

J. Mar. Sci. Eng. 2021, 9(1), 51; https://doi.org/10.3390/jmse9010051 - 05 Jan 2021

Cited by 9 | Viewed by 3420

Abstract

As the number of mixotrophic protists has been increasingly documented, “mixoplankton”, a third category separated from the traditional categorization of plankton into “phytoplankton” and “zooplankton”, has become a new paradigm and research hotspot in aquatic plankton ecology. While species of dinoflagellates are a [...] Read more.

As the number of mixotrophic protists has been increasingly documented, “mixoplankton”, a third category separated from the traditional categorization of plankton into “phytoplankton” and “zooplankton”, has become a new paradigm and research hotspot in aquatic plankton ecology. While species of dinoflagellates are a dominant group among all recorded members of mixoplankton, the trophic modes of Karlodinium, a genus constituted of cosmopolitan toxic species, were reviewed due to their representative features as mixoplankton and harmful algal blooms (HABs)-causing dinoflagellates. Among at least 15 reported species in the genus, three have been intensively studied for their trophic modes, and all found to be phagotrophic. Their phagotrophy exhibits multiple characteristics: (1) omnivority, i.e., they can ingest a variety of preys in many forms; (2) flexibility in phagotrophic mechanisms, i.e., they can ingest small preys by direct engulfment and much bigger preys by myzocytosis using a peduncle; (3) cannibalism, i.e., species including at least K. veneficum can ingest the dead cells of their own species. However, for some recently described and barely studied species, their tropical modes still need to be investigated further regarding all of the above-mentioned aspects. Mixotrophy of Karlodinium plays a significant role in the population dynamics and the formation of HABs in many ways, which thus deserves further investigation in the aspects of physiological ecology, environmental triggers (e.g., levels of inorganic nutrients and/or presence of preys), energetics, molecular (genes and gene expression regulations) and biochemical (e.g., relevant enzymes and signal molecules) bases, origins, and evaluation of the advantages of being a phagotroph. Full article

(This article belongs to the Special Issue Taxonomy and Ecology of Marine Algae)

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