The occurrence of phytoplankton taxa, with special focus on harmful algal bloom (HAB) taxa, was monitored for one year off the central coast of California to examine both their co-occurrence and physical and chemical variables influencing their temporal patterns. Bi-weekly samples were taken from October 6, 2008 to October 5, 2009 in San Luis Obispo Bay, CA. Canonical correspondence analysis (CCA) of weekly samples indicated that 46.1% of the variability in species abundance was explained by the variables in the model, higher than previous reports. Cluster analysis divided phytoplankton communities into HAB and non-HAB groups of species, while shared distribution analysis identified specific co-occurring species of HABs. The HAB dinoflagellate group consisted exclusively of HAB taxa, including Cochlodinium polykrikoides Margalef, Dinophysis acuminata Claparède & Lachmann, and Alexandrium spp., and was correlated with a homogeneous water column and high nitrate concentration during the fall and winter seasons. The domoic acid producing diatoms Pseudo-nitzschia seriata (Cleve) H. Peragallo complex and Pseudo-nitzschia delicatissima (Cleve) Heiden complex grouped with several other non-HAB diatoms, and were correlated with warm, thermally stratified waters of the summer season. These results contradict the classic diatom / dinoflagellate succession theory and suggest that event-scale processes influencing water column stability within seasons may influence the distribution of HAB species in near shore upwelling dominated regions.

We analyzed chlorophyll-a (chl-a) concentrations in shallow, turbid Utah Lake using Landsat data from 1984 to 2021. Utah Lake is ~40 km by 21 km, has a surface area of ~390 km2, an average depth of ~3 m, and loses ~50% of inflow to evaporation. This limits spatial mixing, allowing us to evaluate impacts to smaller lake regions. We evaluated long-term trends at the pixel level and for areas related to boundary conditions. We created 17 study areas based on differences in shoreline development and nutrient inflows. We expected impacted areas to exhibit increasing chl-a trends, as population growth and development in the Utah Lake watershed have been significant. We used the non-parametric Mann-Kendall test to evaluate trends. The majority of the lake exhibited decreasing trends, with a few pixels in Provo and Goshen Bays exhibiting slight increasing or no trends. We estimated trend magnitudes using Sen's slope and fitted linear regression models. Trend magnitudes in all pixels (and regions), both decreasing and increasing, were small; with the largest decreasing and increasing trends being about -0.05 and -0.005 µg/L/year, and about 0.1 and 0.005 µg/L/year for the Sen's slope and linear regression slope, respectively. Over the ~40 year-period, this would result in average decreases of 2 to 0.2 µg/L or increases of 4 and 0.2 µg/L. All the areas exhibited decreasing trends, but the monthly trends in some areas exhibited no trends rather than decreasing trends. Monthly trends for some areas showed some indications that algal blooms are occurring earlier, though evidence is inconclusive. We found essentially no change in algal concentrations in Utah Lake at either the pixel level or for the analysis regions since the 1980's, despite significant population expansion, increased nutrient inflows, and land-use changes. This result matches prior research and supports the hypothesis that algal growth in Utah Lake is not limited by direct nutrient inflows but limited by other factors.

No description available.

No description available.

No description available.

Cooperation presents a major challenge for evolutionary theory: how can competition favor a trait that imposes a cost on the individual expressing it while benefitting another? This challenge has been answered by theory that emphasizes the importance of assortment between individuals that tend to cooperate and those who tend to behave selfishly, or `cheat'. Microbial cooperation remains puzzling, given the generally high genetic and taxonomic diversity of most microbial communities. Many microbial populations rely on shared, beneficial extracellular products for an array of functions in nature. However, when these lineages are maintained in liquid cultures, many are invaded and outcompeted by spontaneous `cheater' mutants that forego investments in these products while benefitting from those produced by neighbors. The apparent evolutionary instability of microbial investments in extracellular products in well-mixed laboratory cultures finds a natural parallel in the phenomenon of toxic microalgal blooms. These extremely dense populations of often free-living microalgae destroy populations of competing microalgae and grazing zooplankton that normally control population densities. Bloom populations of planktonic microalgae are unstructured, and seem ill suited for the evolution of cooperation. In this thesis, I have established a new theoretical framework for understanding the evolution of microbial external goods. This framework highlights the importance of cell-level structure in the distribution of these external products, as well as genetic structuring in populations. This perspective informed an investigation into the social niche of a biofilm-dwelling regulatory mutant of the important biocontrol strain Pseudomonas chlororaphis. In the highly self-structured environment of a bacterial biofilm, a surprising mutualistic association between this mutant and the wild type emerged, underscoring the importance of microbial ecology in understanding the evolution of niche construction. Extending these lessons to the evolutionary problem of exotoxins in free-swimming microalgae yields the novel possibility that fluctuations in density of toxic strains shift a cell-level functioning exotoxin into a true public good that may be exploited by cheaters. I show that exotoxicity can serve cell-level functions in Prymnesium parvum. Despite these cell-level benefits, the existence of nontoxic lineages within toxic blooms hints at a complex interaction between rapid evolutionary and ecological changes in toxic blooms.

Algal blooms are directly related to human-caused nutrient enrichment of water bodies. The cyanobacteria Microcystis aeruginosa produces microcystin (MC), a toxin that has been linked with mortalities and illness of many organisms. We show that MC is not constrained by the aquatic-terrestrial ecotone. MC was detected in a primary consumer and emerging aquatic invertebrate (Hexagenia Mayfly), a terrestrial insect and predator of emerging aquatic invertebrates (Tetragnathidae Spider), and a vertebrate consumer (Prothonotary Warbler). Mayfly and spider MC levels varied across the blooming period. MC levels in prothonotary warbler livers varied by age class; nestlings having the highest levels. MC levels decreased in fledglings over time. A more aquatic diet was related to higher MC levels in nestlings at one site and nestling fecal-sacs varied spatially, also indicating that aquatic diet is related to MC consumption. Warbler body condition and growth rate was not related to liver microcystin levels.

Master of Public Health / Department of Diagnostic Medicine/Pathobiology / Deon Van der Merwe / Cyanobacteria are Gram-negative photosynthetic bacteria capable of producing toxins responsible for morbidity and mortality in humans and domestic animals. Many are capable of forming concentrated blooms that impact the environment by limiting the growth of sub-surface plants and phytoplankton. Harmful algal blooms (HABs) are also capable of producing multiple types of toxins, creating a potential hazard to recreational water users and animals drinking water from or near a bloom. Characterization of HABs is necessary to prevent these human and animal exposures and includes classifying of the type of cyanobacteria present and whether or not they are capable of toxin production, and the exact type of cyanotoxin that is actually present in bloom. Current methods used to classify cyanobacteria and cyanotoxins include microscopy, bioassays, ELISA, PCR, HPLC, and LC/MS. All of these methods, however, have limitations that include time, labor intensity, or cost. Fourier-Transform Infrared Spectroscopy (FTIR) is another potential tool for cyanobacterial classification that is not limited by these factors. To examine the practicality of this method, library screening with default software algorithms was performed on diagnostic samples received at the Kansas State University Veterinary Diagnostic Lab, followed by PCA of samples meeting minimum quality requirements to produce cluster analyses and dendrograms. Both spectrometers and software packages used were successful at distinguishing cyanobacteria from green algae in clean samples with 89.13% agreement. PCA resulted in clear classification of cyanobacteria or green algae demonstrated by a large order of magnitude difference produced by average Euclidian distance dendrograms. While this method is only capable of differentiating cyanobacteria from green algae or other aquatic environmental constituents, its simple, rapid use and low cost make it a beneficial screening tool when coupled with toxin-detection methods to characterize HABs.

This study analyses the spatial and temporal variability of chlorophyll-a in Chesapeake Bay; assesses the performance of Ocean Color 3M (OC3M) algorithm; and develops a novel algorithm to estimate chlorophyll-a for coastal shallow water. The OC3M algorithm yields an accurate estimate of chlorophyll-a concentration for deep ocean water (RMSE=0.016), but it failed to perform well in the coastal water system (RMSE=23.17) of Chesapeake Bay. A novel algorithm was developed which utilizes green and red bands of the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. The novel algorithm derived the chlorophyll-a concentration more accurately in Chesapeake Bay (RMSE=4.20) than the OC3M algorithm. The study indicated that the algorithm that uses red bands could improve the satellite estimation of chlorophyll-a in the coastal water system by reducing the noise associated with bottom reflectance and colored dissolved organic matter (CDOM)

Karenia brevis (Davis cf. Hansen & Moestrup = Gymnodinium breve) is the non-peridinin containing dinoflagellate responsible for many harmful algal blooms (red tides) in the Gulf of Mexico. These recurrent blooms can have significant negative ecological, economic, and human health impacts including fish kills, tainting of shellfish, poisoning of marine mammals, loss of tourism revenue due to beach closures, and respiratory distress and food poisoning in humans. A method for detection of Karenia brevis was developed based upon amplification of the mRNA for the plastid-encoded gene of the carbon fixing enzyme ribulose 1, 5-bisphosphate carboxylase/oxygenase (RuBisCO) large subunit (rbcL). Using sequence information from a primer set targeting a 554-bp region of the Karenia rbcL gene, a small (91 bp amplicon) primer and probe set was created for TaqMan(registered trademark) real time RT-PCR of K. brevis rbcL. The primer/probe set is sensitive to as little as 0.1 fg of target transcript and as little as 1 pg of total cellular K. brevis RNA extract, corresponding to less than 1 cell reaction-1. The primer/probe set did not amplify rbcL transcript from any of the non-target algae tested. Bloom samples analyzed by this method have shown the assay to be a reliable method, with effective enumeration and a linear relationship showing good correlation to the cell counts by microscopy (r2= 0.8344). The assay has been shown to be robust and perform well even in non-ideal conditions, with pre-extraction RNA from unialgal culture stable at room temperature for up to 3 days and up to a month at -80 degrees C in Stratagene's lysis buffer. The transcription of the rbcL gene demonstrated minor variation throughout the diel period, however the variation was not linked to the diel cycle or to carbon fixation, which showed a distinct diel signal. Due to the relatively constant expression of the rbcL gene, the real-time RT-PCR assay developed should be able to reliably enumerate K. brevis populations in the natural environment, as long as the sample is placed in Stratagene's lysis buffer and processed within one or two days or frozen at -80 degrees C and processed within a month.