scholarly journals Genomic adaptation of the picoeukaryote Pelagomonas calceolata to temperate iron-poor oceans revealed by a chromosome-scale genome sequence.

2021 ◽  
Author(s):  
Nina Guerin ◽  
Marta Ciccarella ◽  
Elisa Flamant ◽  
Sophie Mangenot ◽  
Benjamin Istace ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Relative Abundance ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Inorganic Nitrogen ◽  
Coastal Species ◽  
Eukaryotic Phytoplankton ◽  
Trophic Network ◽  
Ecological Importance ◽  
Recombination Pathway

Eukaryotic phytoplankton are key actors in marine ecosystems, they contribute to atmospheric CO2 sequestration and supply organic matter to the trophic network. Among them, Pelagophytes (Stramenopiles) algae are a diverse class with coastal species causative of harmful algal blooms while others are cosmopolites and abundant in open ocean ecosystems. Despite their ecological importance, only a few genomic references exist limiting our capacity to identify them and study their adaptation mechanisms in a changing environment. Here, we report the complete chromosome-scale assembled genome sequence of Pelagomonas calceolata. We identified unusual large low-GC and gene-rich regions potentially hosting centromeres. These particular genomic structures could be explained by the absence of genes necessary for an important recombination pathway in this species. We identified a large repertoire of genes involved in inorganic nitrogen sensing and uptake as well as many genes replacing iron-required proteins potentially explaining its ecological success in oligotrophic waters. Finally, based on this high-quality assembly, we evaluated P. calceolata relative abundance in all oceans using environmental Tara datasets. Our results suggest that P. calceolata is one of the most abundant eukaryote species in the oceans with a relative abundance driven by the high temperature and iron-poor conditions. Collectively, these findings bring new insights into the biology and ecology of P. calceolata and lay the foundation for the analysis of the adaptation and acclimation strategy of this picophytoplankton.

scholarly journals sxtA-Based Quantitative Molecular Assay To Identify Saxitoxin-Producing Harmful Algal Blooms in Marine Waters

2011 ◽  
Vol 77 (19) ◽  
pp. 7050-7057 ◽  
Author(s):  
Shauna A. Murray ◽  
Maria Wiese ◽  
Anke Stüken ◽  
Steve Brett ◽  
Ralf Kellmann ◽  
...  
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Harmful Algal Bloom ◽  
Effective Means ◽  
Molecular Genetic ◽  
Alexandrium Tamarense ◽  
Alexandrium Catenella ◽  
Content Type ◽  
Eukaryotic Phytoplankton ◽  
Novel Method

ABSTRACTThe recent identification of genes involved in the production of the potent neurotoxin and keystone metabolite saxitoxin (STX) in marine eukaryotic phytoplankton has allowed us for the first time to develop molecular genetic methods to investigate the chemical ecology of harmful algal bloomsin situ. We present a novel method for detecting and quantifying the potential for STX production in marine environmental samples. Our assay detects a domain of the genesxtAthat encodes a unique enzyme putatively involved in thesxtpathway in marine dinoflagellates,sxtA4. A product of the correct size was recovered from nine strains of four species of STX-producingAlexandriumandGymnodinium catenatumand was not detected in the non-STX-producingAlexandriumspecies, other dinoflagellate cultures, or an environmental sample that did not contain known STX-producing species. However,sxtA4was also detected in the non-STX-producing strain ofAlexandrium tamarense, Tasmanian ribotype. We investigated the copy number ofsxtA4in three strains ofAlexandrium catenellaand found it to be relatively constant among strains. Using our novel method, we detected and quantifiedsxtA4in three environmental blooms ofAlexandrium catenellathat led to STX uptake in oysters. We conclude that this method shows promise as an accurate, fast, and cost-effective means of quantifying the potential for STX production in marine samples and will be useful for biological oceanographic research and harmful algal bloom monitoring.

scholarly journals Emerging harmful algal blooms caused by distinct seasonal assemblages of the toxic diatom Pseudo-nitzschia in Narragansett Bay, RI, USA

2021 ◽  
Author(s):  
Alexa R Sterling ◽  
Riley D Kirk ◽  
Matthew J Bertin ◽  
Tatiana A Rynearson ◽  
David G Borkman ◽  
...  
Keyword(s):  
Rhode Island ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Inorganic Nitrogen ◽  
Nutrient Status ◽  
Early Summer ◽  
Narragansett Bay ◽  
Seasonal Temperature ◽  
Marine Animals ◽  
Rdna Sequencing

The diatom Pseudo-nitzschia produces the neurotoxin domoic acid (DA) that bioaccumulates in shellfish, causing illness in humans and marine animals upon ingestion. In 2017, high levels of DA in shellfish meat closed shellfish harvest in Narragansett Bay (NBay), Rhode Island for the first time in history, although abundant Pseudo-nitzschia have been observed for over 50 years. What caused these events is unknown: whether an environmental factor altered endemic Pseudo-nitzschia physiology or new DA-producing strain(s) were introduced. To investigate, we conducted weekly sampling from 2017-2019 to compare with 2016 precautionary closure and 2017 closure samples. Particulate DA was quantified by highly sensitive LC-MS/MS and correlated with environmental metadata. Pseudo-nitzschia were identified using high-throughput rDNA sequencing, yielding a detailed understanding of distinct seasonal multi-species assemblages. Low DA was detected throughout 2017-2019, except in recurring peaks in the fall and early summer. Fall DA peaks contained toxigenic species (P. pungens var. pungens, P. multiseries, P. calliantha, and P. subpacifica) as well as a novel P. americana taxon. Fewer species were present during summer DA peaks including toxigenic P. multiseries, P. plurisecta, and P. delicatissima. Most 2017 closure samples contained P. australis. Our data showed P. australis as infrequent but particularly concerning. Recurring Pseudo-nitzschia assemblages were driven by seasonal temperature changes and DA correlated with low dissolved inorganic nitrogen. Thus, the NBay closures were likely caused by resident assemblages dependent on nutrient status as well as the episodic introductions of species that may be a result of oceanographic and climactic shifts.

National coastal management challenges and needs

Shore & Beach ◽  
2020 ◽  
pp. 34-43
Author(s):  
Nicole Elko ◽  
Tiffany Roberts Briggs
Keyword(s):  
Coastal Management ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Local Community ◽  
Extreme Event ◽  
Technical Information ◽  
Interdisciplinary Approach ◽  
Beach Erosion ◽  
The U.S

In partnership with the U.S. Geological Survey Coastal and Marine Hazards and Resources Program (USGS CMHRP) and the U.S. Coastal Research Program (USCRP), the American Shore and Beach Preservation Association (ASBPA) has identified coastal stakeholders’ top coastal management challenges. Informed by two annual surveys, a multiple-choice online poll was conducted in 2019 to evaluate stakeholders’ most pressing problems and needs, including those they felt most ill-equipped to deal with in their day-to-day duties and which tools they most need to address these challenges. The survey also explored where users find technical information and what is missing. From these results, USGS CMHRP, USCRP, ASBPA, and other partners aim to identify research needs that will inform appropriate investments in useful science, tools, and resources to address today’s most pressing coastal challenges. The 15-question survey yielded 134 complete responses with an 80% completion rate from coastal stakeholders such as local community representatives and their industry consultants, state and federal agency representatives, and academics. Respondents from the East, Gulf, West, and Great Lakes coasts, as well as Alaska and Hawaii, were represented. Overall, the prioritized coastal management challenges identified by the survey were: Deteriorating ecosystems leading to reduced (environmental, recreational, economic, storm buffer) functionality, Increasing storminess due to climate change (i.e. more frequent and intense impacts), Coastal flooding, both Sea level rise and associated flooding (e.g. nuisance flooding, king tides), and Combined effects of rainfall and surge on urban flooding (i.e. episodic, short-term), Chronic beach erosion (i.e. high/increasing long-term erosion rates), and Coastal water quality, including harmful algal blooms (e.g. red tide, sargassum). A careful, systematic, and interdisciplinary approach should direct efforts to identify specific research needed to tackle these challenges. A notable shift in priorities from erosion to water-related challenges was recorded from respondents with organizations initially formed for beachfront management. In addition, affiliation-specific and regional responses varied, such as Floridians concern more with harmful algal blooms than any other human and ecosystem health related challenge. The most common need for additional coastal management tools and strategies related to adaptive coastal management to maintain community resilience and continuous storm barriers (dunes, structures), as the top long-term and extreme event needs, respectively. In response to questions about missing information that agencies can provide, respondents frequently mentioned up-to-date data on coastal systems and solutions to challenges as more important than additional tools.

scholarly journals Marine harmful algal blooms (HABs) in the United States: History, current status and future trends

Harmful Algae ◽  
2021 ◽  
pp. 101975
Author(s):  
Donald M. Anderson ◽  
Elizabeth Fensin ◽  
Christopher J. Gobler ◽  
Alicia E. Hoeglund ◽  
Katherine A. Hubbard ◽  
...  
Keyword(s):  
United States ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
United States History ◽  
The United States ◽  
Current Status ◽  
Future Trends ◽  
States History

scholarly journals Mitochondrial genome evolution in pelagophyte algae

2021 ◽  
Author(s):  
Shannon J Sibbald ◽  
Maggie Lawton ◽  
John M Archibald
Keyword(s):  
Mitochondrial Genome ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
23S Rrna ◽  
Mitochondrial Genomes ◽  
Trna Genes ◽  
Unique Region ◽  
Long Read ◽  
Genomic Studies ◽  
Aureoumbra Lagunensis

Abstract The Pelagophyceae are marine stramenopile algae that include Aureoumbra lagunensis and Aureococcus anophagefferens, two microbial species notorious for causing harmful algal blooms. Despite their ecological significance, relatively few genomic studies of pelagophytes have been carried out. To improve understanding of the biology and evolution of pelagophyte algae, we sequenced complete mitochondrial genomes for A. lagunensis (CCMP1510), Pelagomonas calceolata (CCMP1756) and five strains of A. anophagefferens (CCMP1707, CCMP1708, CCMP1850, CCMP1984 and CCMP3368) using Nanopore long-read sequencing. All pelagophyte mitochondrial genomes assembled into single, circular mapping contigs between 39,376 base-pairs (bp) (P. calceolata) and 55,968 bp (A. lagunensis) in size. Mitochondrial genomes for the five A. anophagefferens strains varied slightly in length (42,401 bp—42,621 bp) and were 99.4%-100.0% identical. Gene content and order was highly conserved between the A. anophagefferens and P. calceolata genomes, with the only major difference being a unique region in A. anophagefferens containing DNA adenine and cytosine methyltransferase (dam/dcm) genes that appear to be the product of lateral gene transfer from a prokaryotic or viral donor. While the A. lagunensis mitochondrial genome shares seven distinct syntenic blocks with the other pelagophyte genomes, it has a tandem repeat expansion comprising ∼40% of its length, and lacks identifiable rps19 and glycine tRNA genes. Laterally acquired self-splicing introns were also found in the 23S rRNA (rnl) gene of P. calceolata and the coxI gene of the five A. anophagefferens genomes. Overall, these data provide baseline knowledge about the genetic diversity of bloom-forming pelagophytes relative to non-bloom-forming species.

scholarly journals Performance of a Handheld Chlorophyll-a Fluorometer: Potential Use for Rapid Algae Monitoring

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1409
Author(s):  
Hamdhani Hamdhani ◽  
Drew E. Eppehimer ◽  
David Walker ◽  
Michael T. Bogan
Keyword(s):  
Chlorophyll A ◽  
Surface Waters ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Water Quality Monitoring ◽  
Ambient Light ◽  
Calibration Equation ◽  
Field Samples ◽  
Potential Use

Chlorophyll-a measurements are an important factor in the water quality monitoring of surface waters, especially for determining the trophic status and ecosystem management. However, a collection of field samples for extractive analysis in a laboratory may not fully represent the field conditions. Handheld fluorometers that can measure chlorophyll-a in situ are available, but their performance in waters with a variety of potential light-interfering substances has not yet been tested. We tested a handheld fluorometer for sensitivity to ambient light and turbidity and compared these findings with EPA Method 445.0 using water samples obtained from two urban lakes in Tucson, Arizona, USA. Our results suggested that the probe was not sensitive to ambient light and performed well at low chlorophyll-a concentrations (<25 µg/L) across a range of turbidity levels (50–70 NTU). However, the performance was lower when the chlorophyll-a concentrations were >25 µg/L and turbidity levels were <50 NTU. To account for this discrepancy, we developed a calibration equation to use for this handheld fluorometer when field monitoring for potential harmful algal blooms in water bodies.

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