scholarly journals Insights into toxic Prymnesium parvum blooms: the role of sugars and algal viruses

2018 ◽  
Vol 46 (2) ◽  
pp. 413-421 ◽  
Author(s):  
Ben A. Wagstaff ◽  
Edward S. Hems ◽  
Martin Rejzek ◽  
Jennifer Pratscher ◽  
Elliot Brooks ◽  
...  

Prymnesium parvum is a toxin-producing microalga that causes harmful algal blooms globally, which often result in large-scale fish kills that have severe ecological and economic implications. Although many toxins have previously been isolated from P. parvum, ambiguity still surrounds the responsible ichthyotoxins in P. parvum blooms and the biotic and abiotic factors that promote bloom toxicity. A major fish kill attributed to P. parvum occurred in Spring 2015 on the Norfolk Broads, a low-lying set of channels and lakes (Broads) found on the East of England. Here, we discuss how water samples taken during this bloom have led to diverse scientific advances ranging from toxin analysis to discovery of a new lytic virus of P. parvum, P. parvum DNA virus (PpDNAV-BW1). Taking recent literature into account, we propose key roles for sialic acids in this type of viral infection. Finally, we discuss recent practical detection and management strategies for controlling these devastating blooms.

2021 ◽  
Author(s):  
Alice Pietri ◽  
François Colas ◽  
Mogollon Rodrigo ◽  
Jorge Tam ◽  
Dimitri Gutierrez

<p>Extreme climatic events, such as marine heatwaves (MHWs), have been shown to globally increase in frequency and magnitude over the last decades, and can disrupt ecosystems significantly. Coastal upwelling systems, because they are biodiversity hot-spots and socioeconomic hubs, are particularly vulnerable to those rapidly developing anomalously warm marine events. The Peruvian coastal system in particular is highly exposed to climate variability because of its proximity to the equator. As such it is regularly impacted by El Niño events whose variability has been related to the longest and most intense MHWs in the region. However the intensively studied El Niño events tend to overshadow the MHWs of shorter duration that also have an important impact on the coastal environment as they can trigger other extreme events such as nearshore hypoxias and harmful algal blooms. </p><p>Using 38 years of satellite sea surface temperature data, we investigate the characteristics (spatial variability, frequency, intensity and duration) and evolution of MHWs in the South Tropical Eastern Pacific, with a focus on the Peru Coastal Upwelling System. The separation of events by duration allows to identify a spectrum, from El Niño events to shorter scale MHWs. Results show that the statistical  distribution of MHWs properties, their spatial organization and preferential season of occurrence varies significantly in function of their duration. Besides, when removing large El Niño events, an increase of occurrences, duration and intensity is observed over the last 38 years, contrary to the reduction that is observed in the region when considering all MHWs. Finally, the possible drivers are discussed to disentangle the role of the local (wind stress) and remote (equatorial variability) forcing in function of the events duration.</p>


2010 ◽  
Vol 85 (1-2) ◽  
pp. 122-135 ◽  
Author(s):  
R.M. Kudela ◽  
S. Seeyave ◽  
W.P. Cochlan

Author(s):  
Hamed Mohammed Al Gheilani ◽  
Kazumi Matsuoka ◽  
Abdulaziz Yahya AlKindi ◽  
Shehla Amer ◽  
Colin Waring

Red tide, one of the harmful algal blooms (HABs) is a natural ecological phenomenon and often this event is accompanied by severe impacts on coastal resources, local economies, and public health. The occurrence of red tides has become more frequent in Omani waters in recent years. Some of them caused fish kill, damaged fishery resources and mariculture, threatened the marine environment and the osmosis membranes of desalination plants. However, a number of them have been harmless. The most common dinoflagellate Noctiluca scintillans is associated with the red tide events in Omani waters. Toxic species like Karenia selliformis, Prorocentrum arabianum, and Trichodesmium erythraeum have also been reported recently. Although red tides in Oman have been considered a consequence of upwelling in the summer season (May to September), recent phytoplankton outbreaks in Oman are not restricted to summer. Frequent algal blooms have been reported during winter (December to March). HABs may have contributed to hypoxia and/or other negative ecological impacts. 


2021 ◽  
Vol 8 ◽  
Author(s):  
María del Carmen Jiménez-Quiroz ◽  
Francisco Javier Barrón-Barraza ◽  
Rafael Cervantes-Duarte ◽  
René Funes-Rodríguez

This study presents an overview of bivalve assemblages in Bahia Magdalena (BM, México) and the possible impact of environmental variability on these populations, constantly stressed by fishing. This lagoon is responsible for a high proportion of harvest of regional bivalves. First, we list the bivalve species reported in public biogeographic databases. Based on eight commercially exploited species, we described the composition of the bivalve assemblage and its biological characteristics, the history of fishery, and environmental variability in the marine area adjacent to the lagoon (1970–2019) and the habitat of bivalves (2002–2020). Sources of data were public databases and published literature. The enlisted species (n = 184) belong to six orders, and most are small and infaunal, but the structure of the assemblage is unknown. The fisheries began at different times and focused on the most valuable resources. Almost all harvest of bivalves had wide variations because of intensive fishing and a weak regulation frame. After 2015, the main resources were the Pacific wing-oyster (a new resource since 2017) and the geoduck clam due to the declining abundance of other resources (e.g., pen shells, Pacific calico scallop). There was a warming trend in the region since the 1970's, but the strongest El Niño-Southern Oscillation (ENSO) phases caused the most notable changes before 2013; after that year, a combination of large-scale phenomena increased the temperature significantly. The trend of chlorophyll-a abundance negatively correlated with temperature, but there was an almost constant supply of particulate organic matter in the interior of Bahia Magdalena (BM). After 2015, the quality of lagoon water gradually deteriorated, and in 2017 and 2019, harmful algal blooms developed, but the impact was not fully assessed. The challenges faced by the fishery are multiple (institutional weakness and regional warming); however, permanent monitoring programs of environmental conditions and critical biological variables should be implemented to design scenarios that allow fishery sustainability.


2020 ◽  
Vol 71 (5) ◽  
pp. 636 ◽  
Author(s):  
Elżbieta Wilk-Woźniak

Cyanobacterial harmful algal blooms are known all around the world. Climate change (temperature increase) and human activity (eutrophication) are factors that promote the proliferation of cyanobacteria, leading to the development of blooms and the release of toxins. Abiotic and biotic factors are responsible for the development of blooms and how long they last. Although the abiotic factors controlling blooms are well known, knowledge of biotic factors and their interactions is still lacking. This paper reviews five levels of biotic interactions, namely cyanobacteria–zooplankton, cyanobacteria–ciliates, cyanobacteria–bacteria, cyanobacteria–viruses and cyanobacteria–fungi, showing a more complex food web network than was previously thought. New findings published recently, such as the relationships between cyanobacteria and viruses or cyanobacteria and fungi, indicate that cyanobacterial blooms are not the end of the cycle of events taking place in water habitats, but rather the middle of them. As such, a new approach needs to consider mutual connections, genetic response, horizontal gene transfer and non-linear flow of carbon.


2014 ◽  
Vol 281 (1781) ◽  
pp. 20133316 ◽  
Author(s):  
Nicholas D. Pyenson ◽  
Carolina S. Gutstein ◽  
James F. Parham ◽  
Jacobus P. Le Roux ◽  
Catalina Carreño Chavarría ◽  
...  

Marine mammal mass strandings have occurred for millions of years, but their origins defy singular explanations. Beyond human causes, mass strandings have been attributed to herding behaviour, large-scale oceanographic fronts and harmful algal blooms (HABs). Because algal toxins cause organ failure in marine mammals, HABs are the most common mass stranding agent with broad geographical and widespread taxonomic impact. Toxin-mediated mortalities in marine food webs have the potential to occur over geological timescales, but direct evidence for their antiquity has been lacking. Here, we describe an unusually dense accumulation of fossil marine vertebrates from Cerro Ballena, a Late Miocene locality in Atacama Region of Chile, preserving over 40 skeletons of rorqual whales, sperm whales, seals, aquatic sloths, walrus-whales and predatory bony fish. Marine mammal skeletons are distributed in four discrete horizons at the site, representing a recurring accumulation mechanism. Taphonomic analysis points to strong spatial focusing with a rapid death mechanism at sea, before being buried on a barrier-protected supratidal flat. In modern settings, HABs are the only known natural cause for such repeated, multispecies accumulations. This proposed agent suggests that upwelling zones elsewhere in the world should preserve fossil marine vertebrate accumulations in similar modes and densities.


Oceanography ◽  
2005 ◽  
Vol 18 (2) ◽  
pp. 198-209 ◽  
Author(s):  
Patricia Glibert ◽  
Sybil Seitzinger ◽  
Cynthia Heil ◽  
JoAnn Burkholder ◽  
Matthew Parrow ◽  
...  

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