Understanding cyanobacterial harmful algal blooms (cyanoHABs) requires reliable scientific information on the species present in a bloom, genetic information on their capacity to produce cyanotoxins and the environmental ques that cause a species to initiate the cyanotoxin synthesis process (Pearson and Neilan, 2008, Davis et al. 2009, Burford et al. 2014, Pacheco et. al. 2016, Rosen et al., 2017). Traditional methods for identifying cyanobacteria relied exclusively on morphological characteristics (Anagnostidis and Komárek 1985). The advent of genetic sequencing has led to a polyphasic approach that removes some of the ambiguity that is derived from overlapping morphological features (Zapomělová et al. 2009, Komárek et al. 2014, Komárek 2016). Combining proper taxonomic assignment of organisms with their genetic information and actual toxin production, provides the foundation for advancing the understand of cyanoHABs and their potential impact on society (ecosystems and humans).
The U.S. Geological Survey (USGS) is collaborating internally and with federal agencies, state agencies, universities, public utilities, and Tribes to collect as many cyanobacteria species forming blooms and potentially producing toxins. Live samples are shipped directly to our research laboratory where organisms are photographed, morphological features documented, and individual species are brought into culture for additional studies.
Exposure to cyanobacterial toxins, such as anatoxins, cylindrospermopsins, microcystins, nodularins, and saxitoxins can result in significant health risks and can lead to mammalian mortality or illness (Kuiper-Goodman et al. 1999; Carmichael, 2001; Pearson et al. 2010). Currently, the most commonly detected cyanotoxins are the microcystins that are non-ribosomal peptide or polyketide toxins and common cyclic peptide structure (Welker and von Dohren, 2006) which inhibit protein phosphatases in the liver (Rinehart et al. 1994). Although the genus Microcystis has members that are known to produce this compound (Neilan et al. 1999), phylogenically disparate organisms such as Planktothrix (Christiansen et al. 2003) and Dolichospermum (Rouhianen 2004) are also known to synthesize microcystins.
The cylindrospermopsins are alkaloids with guanidinium and sulfate groups, with hepatotoxic, nephrotoxic and cytological effects (Falconer et al. 1999, Runnegar et al. 2002). Known producers of this compound include Cylindrospermopsis raciborskii (Ohtani et al. 1992; Sinha et al. 2014), Chyrsosporum ovalisporum (Banker et al. 1997), Rhaphidiopsis curvata (Li et al. 2001), Anabaena (Spoof et al. 2006) and other genera. Loftin et al. (2016) found 7% of lakes surveyed had detection of cylindrospermopsin, although attributing this compound to any given organism in a bloom needs greater study. For example, in the summer of 2017 the network of samples acquired by the USGS algae laboratory in Orlando had many locations with the presence of a previously unidentified organism, tentatively identified as Umezakia, a known producer of cylindrospermopsin (Terao et al. 1994), but it is unknown if this organism was producing this compound or posed a risk to humans and wildlife.
The nodularins are cyclic peptides commonly associated with the genus Nodularia. Although Nodularia spumigena blooms in water bodies, such as the Great Salt Lake, it is unclear if other organisms are synthesizing nodularins, given their prevalence in 4% of the lakes assessed (Loftin et al. 2016).
Improving the knowledge base of cyanobacteria in a harmful algal bloom centers on 1) accurately characterizing the morphology of the bloom-forming organism(s) so they can be properly identified and quantified (Rosen et al. 2017) with traditional microscopic techniques; 2) isolate and culture the bloom-forming species to examine both their toxin production and for the genes needed for toxin production. Many of the less common bloom-forming species have not been examined for their ability to make toxins. It is important to characterize these organisms because blooms are constantly changing, and examples of unidentified organisms blooming have the potential to be harmful. Genetic analyses of the unknown organisms, and contributing these data to genetic repositories like GenBank, will increase the robustness of monitoring programs that are relying more frequently on genomic data. Genetic information also provides insight into the regulation toxin production (Neilan et al. 2013).
This Mendenhall Research Fellowship will provide an excellent opportunity for an early career researcher to work collaboratively with USGS scientists and agency managers to provide scientific information through microscopic identification, novel enumeration techniques and genetic approaches that will be the foundational information for decision making. A team of scientists working across disciplines are participating in this effort and there is substantial room for creative approaches by the Mendenhall Fellow to propose original research to understand and improve our knowledge of species and their potential to cause harm to humans and wildlife. The research is expected to result in widely-distributed visual database and publications of toxin-producing cyanobacteria species. The postdoctoral researcher’s contributions are expected to provide insight into the less common species found in blooms, contribute data to genetic repositories, and advance our understanding of cyanobacterial bloom dynamics.
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Proposed Duty Station: Orlando, FL.
Areas of PhD: Phycology, microbial genetics, phytoplankton culturing, biology (candidates holding a Ph.D. in other disciplines, but with extensive knowledge and skills relevant to the Research Opportunity may be considered).
Qualifications: Applicants must meet one of the following qualifications: Research Biologist; Research Ecologist; Research Microbiologist. (This type of research is performed by those who have backgrounds for the occupations stated above. However, other titles may be applicable depending on the applicant's background, education, and research proposal. The final classification of the position will be made by the Human Resources specialist.)
Research Advisor(s): Barry Rosen, (407) 738-0669, firstname.lastname@example.org.
Human Resources Office Contact: Diana Panchal, 703-648-7464, email@example.com
|Summary of Opportunities|