A new recorded of red tide forming species; Heterocapsa triquetra, Gymnodinium impudicum, Heterosigma akashiwo and Thalassiosira rotula in Alexandria Waters, Egypt

Mikhail, Samia K.; Khalil, Nehma; El-Hadary, M. H.

doi:10.21608/ejabf.2020.117258

Cited by 7 publications

(3 citation statements)

References 40 publications

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“…However, relatively higher cell densities (>10 6 cells L −1 ) have been reported during A. minutum blooms on both the Mediterranean and Atlantic coasts [45,[53][54][55][56][57][58][59][60][61]. The highest concentration of G. impudicum (33.9 × 10 5 cells L −1 ) observed in this study was higher than that (2.0-6.3 × 10 5 cells L −1 ) recorded on the Catalan coast [49] but lower than the highest abundance (71.2 × 10 5 cells L −1 ) of G. impudicum observed in Alexandria (Egypt, southeastern Mediterranean coast) [62].…”

Section: Hab Identification and Densitiescontrasting

confidence: 77%

Prokaryotic Diversity and Dynamics during Dinoflagellate Bloom Decays in Coastal Tunisian Waters

et al. 2023

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(1) Background: Harmful algal blooms (HABs) can negatively impact marine ecosystems, but few studies have evaluated the microbial diversity associated with HABs and its potential role in the fates of these proliferations. (2) Methods: Marine prokaryotic diversity was investigated using high-throughput sequencing of the 16S rRNA gene during the bloom declines of two dinoflagellates detected in the summer of 2019 along the northern and southern Tunisian coasts (South Mediterranean Sea). The species Gymnodinium impudicum (Carthage, Tunis Gulf) and Alexandrium minutum (Sfax, Gabes Gulf) were identified using microscopy and molecular methods and were related to physicochemical factors and prokaryotic compositions. (3) Results: The abundance of G. impudicum decreased over time with decreasing phosphate concentrations. During the G. impudicum bloom decay, prokaryotes were predominated by the archaeal MGII group (Thalassarchaeaceae), Pelagibacterales (SAR11), Rhodobacterales, and Flavobacteriales. At Sfax, the abundance of A. minutum declined with decreasing phosphate concentrations and increasing pH. At the A. minutum peak, prokaryotic communities were largely dominated by anoxygenic phototrophic sulfur-oxidizing Chromatiaceae (Gammaproteobacteria) before decreasing at the end of the survey. Both the ubiquitous archaeal MGII group and Pelagibacterales were found in low proportions during the A. minutum decay. Contrary to the photosynthetic Cyanobacteria, the photo-autotrophic and -heterotrophic Rhodobacterales and Flavobacteriales contents remained stable during the dinoflagellate bloom decays. (4) Conclusions: These results indicated changes in prokaryotic community diversity during dinoflagellate bloom decays, suggesting different bacterial adaptations to environmental conditions, with stable core populations that were potentially able to degrade HABs.

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Section: Hab Identification and Densitiescontrasting

confidence: 77%

Prokaryotic Diversity and Dynamics during Dinoflagellate Bloom Decays in Coastal Tunisian Waters

et al. 2023

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“…However, the processes driving the formation of blooms remain unclear, and a positive relationship between HABs and increased inorganic nutrient inputs of anthropogenic origin has never been convincingly demonstrated (Zingone & Waytt 2012). Recently, Mikhail et al (2020) presented new evidence and alternative interpretations for Alexandria waters, which do not support the conclusions of previous studies.…”

Section: Ecological Significance: Emphasis On Bloom Formationmentioning

confidence: 63%

Intercellular and extracellular amino acids of different bloom species in the Mediterranean Sea

Hosny

El‐Sheekh

Labib

2022

OandHS

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The presented laboratory experiment was designed to characterize the quantity and compositional variation of algal extracellular amino acids (AAs) that may represent an alternative nutrient source in a natural environment. To resemble algal bloom scenarios, analyses were conducted in mono- and/or co-cultures of the bloom-forming species Skeletonema costatum, Scrippsiella trochoidea, Ulva fasciata, and Corallina officinalis during their active growth phase. The study revealed that S. costatum exhibited higher production of the dominant AAs than S. trochoidea. Alanine, lysine, and threonine acids are the dominant amino acids in S. costatum and S. trochoidea filtrates, which may play a role in mucus formation during mucosal phytoplankton blooms with negative ecological effects. On the other hand, aspartic, glutamine, alanine, and leucine acids are the dominant amino acids in macroalgae. In co-culture experiments, U. fasciata shows strong and rapid allelopathic activity against these two potentially harmful species. The AA production offers an advantage to species with the capacity to absorb them to form blooms. Thus, anthropogenic inorganic nutrient inputs may be less important for the development of algal blooms in coastal waters. A major difference that distinguishes this work from others is the use of specific multi-taxa cultures of phytoplankton and macroalgae. The study represents a new research effort in Alexandria waters.

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“…Generally, the centric diatom, T. pseudonana (Hustedt) Hasle et Heimdal, registered cosmopolitan, freshwater and marine diatom was the pioneer; this species occasionally reaches 10.8x10 6 cells l -1 in Alexandria waters (Labib, 2002). The raphidophyte, H. akashiwo recently introduced as an alien species in Alexandria waters (Mikhail, 2001), succeeded in forming recurrent harmful blooms during summer and fall, with limited fish mortality (Mikhail et al, 2020). Micromonas sp.…”

Section: Cordatum Recently By Skarlato Et Al (2018b)mentioning

confidence: 99%

Spring algal blooms in Alexandria coastal area (Egypt) impacted by anthropogenic forcing: Potential role of habitat alteration

Mikhail et al.

2023

Egypt. J. of Aquatic Biolo. and Fish.

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Indeed, frequent and periodic local bloom events are becoming long-term chronic problems given their regular annual occurrence from late spring to early autumn, although with particularities concerning the duration and proliferating species. Despite the spring blooms having been a recurring feature of an annually regular occurrence in Alexandria waters (Labib, 2002), no consensus, in general, has been reached yet on the initial mechanisms and triggers, a matter under debate still for the most part its infancy.The current study is a part of the formal national monitoring program established in 2021 by the National Institute of Oceanography and Fisheries within the framework of the research project entitled "Assessment of red tide phenomena in the Egyptian neritic waters: causes and impacts" funded by the Institute. The program was designed to implement control strategies aimed at impeding/alleviating massive outbreaks and their potential negative impacts.The study was conducted in the Mex and Qaitbay areas which are vulnerable to annually recurrent algal bloom outbreaks affected by heavy substantial anthropogenic eutrophication and are subjected to rapid coastal foundation processes. The study aims to achieve two goals: 1) to investigate the ambient environmental variables that might force the blooms triggering between late April and late May 2021, abundances of the causative species, and biomass accumulation, and 2) to explore the potential impacts of newly created semi-enclosed microhabitats on the occurrence and biomass accumulation of red tide blooms. To bridge the driving forces, the water quality and other biological elements were investigated inside microhabitats in comparison with the properties of the adjacent outside wave-exposed sites. The gained knowledge assists policymakers and managers in coping properly with environmental problems, favoring coastal conservation, restoring coastal ecosystems, and maintaining the services they provide.

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A new recorded of red tide forming species; Heterocapsa triquetra, Gymnodinium impudicum, Heterosigma akashiwo and Thalassiosira rotula in Alexandria Waters, Egypt

Cited by 7 publications

References 40 publications

Prokaryotic Diversity and Dynamics during Dinoflagellate Bloom Decays in Coastal Tunisian Waters

Prokaryotic Diversity and Dynamics during Dinoflagellate Bloom Decays in Coastal Tunisian Waters

Intercellular and extracellular amino acids of different bloom species in the Mediterranean Sea

Spring algal blooms in Alexandria coastal area (Egypt) impacted by anthropogenic forcing: Potential role of habitat alteration

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