@inbook {316,
	title = {Laboratory analysis of nutrient stress and toxin accumulation in Pseudo-nitzschia species from Monterey Bay, California},
	booktitle = {Harmful Algae 2002},
	year = {2004},
	pages = {136-138},
	publisher = {Florida Fish and Wildlife Conservation Commission, Florida Institute of Oceanography and Intergovernmental Oceanographic Commission of UNESCO},
	organization = {Florida Fish and Wildlife Conservation Commission, Florida Institute of Oceanography and Intergovernmental Oceanographic Commission of UNESCO},
	author = {Kudela, R. M. and Roberts, A. and Armstrong, M.},
	editor = {Steidinger, K. and Landsberg, J. H. and Tomas, C. and Vargo, G.}
}
@article {474,
	title = {Nitrogenous preference of toxigenic Pseudo-nitzschia australis (Bacillariophyceae) from field and laboratory experiments},
	journal = {Harmful Algae},
	volume = {6},
	number = {2},
	year = {2007},
	note = {138WSTimes Cited:15Cited References Count:48},
	month = {Feb},
	pages = {206-217},
	abstract = {Field and laboratory experiments were designed to determine the differential growth and toxin response to inorganic and organic nitrogen additions in Pseudo-nitzschia spp. Nitrogen enrichments of 50 mu M nitrate (KNO3), 10 mu M ammonium (NH4Cl), 20 mu M urea and a control (no addition) were carried out in separate carboys with seawater collected from the mouth of the San Francisco Bay (Bolinas Bay), an area characterized by high concentrations of macronutrients and iron. All treatments showed significant increases in biomass, with chlorophyll a peaking on days 4-5 for all treatments except urea, which maintained exponential growth through the termination of the experiment. Pseudo-nitzschia australis Frenguelli abundance was 10(3) cells l(-1) at the start of the experiment and increased by an order of magnitude by day 2. Particulate domoic acid (pDA) was initially low but detectable (0.15 mu g l(-1)), and increased throughout exponential and stationary phases across all treatments. At the termination of the experiment, the urea treatment produced more than double the amount of pDA (9.39 mu g l(-1)) than that produced by the nitrate treatment (4.26 mu g l(-1)) and triple that of the control and ammonium treatments (1.36 mu g l(-1) and 2.64 mu g l(-1), respectively). The mean specific growth rates, calculated from increases in chlorophyll a and from cellular abundance of P australis, were statistically similar across all treatments.These field results confirmed laboratory experiments conducted with a P. australis strain isolated from Monterey Bay, CA (isolate AU221-a) grown in artificial seawater enriched with 50 mu M nitrate, 50 mu M ammonium or 25 mu M of urea as the sole nitrogen source. The exponential growth rate of P australis was significantly slower for cells grown on urea (ca. 0.5 day(-1)) compared to the cells grown on either nitrate or ammonium (ca. 0.9 day(-1)). However the urea-grown cells produced more particulate and dissolved domoic acid (DA) than the ammonium- or nitrate-grown cells. The field and laboratory experiments demonstrate that P australis is able to grow effectively on urea as the primary source of nitrogen and produced more pDA when grown on urea in both natural assemblages and unialgal cultures. These results suggest that the influence of urea from coastal runoff may prove to be more important in the development or maintenance of toxic blooms than previously thought, and that the source of nitrogen may be a determining factor in the relative toxicity of west coast blooms of P. australis. (c) 2006 Elsevier B.V. All rights reserved.},
	keywords = {artificial seawater medium, Batch culture, california, diatom pseudonitzschia-australis, domoic acid, domoic acid production, harmful algae, monterey bay, multiseries, nitrogen, phytoplankton, Pseudo-nitzschia australis, silicate limitation, urea, west-coast},
	isbn = {1568-9883},
	url = {<Go to ISI>://000244394600005},
	author = {Howard, M. D. A. and Cochlan, W. P. and Ladizinsky, N. and Kudela, R. M.}
}
@article {607,
	title = {Inorganic and organic nitrogen uptake by the toxigenic diatom Pseudo-nitzschia australis (Bacillariophyceae)},
	journal = {Harmful Algae},
	volume = {8},
	number = {1},
	year = {2008},
	note = {Sp. Iss. SI384RRTimes Cited:7Cited References Count:79},
	month = {Dec},
	pages = {111-118},
	abstract = {The nitrogen uptake capabilities of the toxigenic diatom Pseudo-nitzschia australis (Frenguelli), freshly isolated from Monterey Bay California, were examined in unialgal laboratory cultures at saturating photosynthetic photon flux densities (100 mu mol photons m(-2) s(-1)) and 15 degrees C. The kinetics of nitrogen (nitrate, ammonium, urea and glutamine) uptake as a function of substrate concentration were estimated from short (20.5 min) incubations using the N-15-tracer technique. Based on the estimated maximum specific uptake rates and measures of N affinity(the initial slope of the uptake versus nutrient concentration curve), nitrate is the preferred nitrogen substrate, followed by glutamine and ammonium,which are equivalent. Rates of urea uptake by P. australis did not saturate at concentrations as high as 36 mu g-at N L-1, and urea uptake as a function of concentration could not be described by Michaelis-Menten kinetics over the concentration gradient tested. Although there is a clear preference for nitrate at equivalent concentrations (compared to ammonium, urea, and glutamine), these laboratory results demonstrate the capability of this pennate diatom to utilize both inorganic and organic forms of nitrogen, supporting field observations that A australis blooms during both upwelling and non-upwelling conditions. off the west coast of North America. Substantial differences in the nitrogenous nutrition of P. australis can be expected in these environments, and anthropogenic inputs of N substrates such as ammonium and urea can support its growth, and may contribute significantly to both harmful diatom blooms and the maintenance of seed populations at non-bloom abundances, particularly during periods of reduced or absent upwelling. (C) 2008 Elsevier B.V. All rights reserved.},
	keywords = {2 marine diatoms, ammonium, Bacillariophyceae, diatom, domoic acid production, environmental-conditions, glutamine, limiting nutrient, nitrate, nitrate uptake kinetics, nitrogen uptake kinetics, prorocentrum-minimum, Pseudo-nitzschia australis, skeletonema-costatum, southern california, urea, urease activity, washington-state},
	isbn = {1568-9883},
	url = {<Go to ISI>://000261762400014},
	author = {Cochlan, W. P. and Herndon, J. and Kudela, R. M.}
}
@article {606,
	title = {The potential role of anthropogenically derived nitrogen in the growth of harmful algae in California, USA},
	journal = {Harmful Algae},
	volume = {8},
	number = {1},
	year = {2008},
	note = {Sp. Iss. SI384RRTimes Cited:7Cited References Count:54},
	month = {Dec},
	pages = {103-110},
	abstract = {Cultural eutrophication is frequently invoked as one factor in the global increase in harmful algal blooms, but is difficult to definitively. prove due to the myriad of factors influencing coastal phytoplankton bloom development. To assess whether eutrophication could be a factor in the development of harmful algal blooms in California (USA), we review the ecophysiological potential for urea uptake by Pseudo-nitzschia australis (Bacillariophyceae), Heterosigma akashiwo (Raphidophyceae), and Lingulodinium polyedrum (Dinophyceae), all of which have been found at bloom concentrations and/or exhibited noxious effects in recent years in California coastal waters. We include new measurements from a large (Chlorophyll a > 500 mg m(-3)) red tide event dominated by Akashiwo sanguinea (Dinophyceae) in Monterey Bay, CA during September 2006. All of these phytoplankton are capable of using nitrate, ammonium, and urea, although their preference for these nitrogenous substrates varies. Using published data and recent coastal time series measurements conducted in Monterey Bay and San Francisco Bay, CA, we show that urea, presumably from coastal eutrophication, was present in California waters at measurable concentrations during past harmful algal bloom events. Based on these observations, we suggest that urea uptake could potentially sustain these harmful algae, and that urea, which is seldom measured as part of coastal monitoring programs, may be associated with these harmful algal events in California. (C) 2008 Elsevier B.V. All rights reserved.},
	keywords = {ammonium, Eutrophication, heterosigma-akashiwo, laboratory cultures, marine-phytoplankton, nitrate, nitrate uptake, nitrogen uptake kinetics, phytoplankton blooms, Pseudo-nitzschia, santa-barbara channel, southern-california, uptake kinetics, urea},
	isbn = {1568-9883},
	url = {<Go to ISI>://000261762400013},
	author = {Kudela, R. M. and Lane, J. Q. and Cochlan, W. P.}
}
@article {532,
	title = {Cryptic blooms: Are thin layers the missing connection?},
	journal = {Estuaries and Coasts},
	volume = {31},
	number = {2},
	year = {2008},
	note = {270CCTimes Cited:1Cited References Count:20},
	month = {Apr},
	pages = {396-401},
	abstract = {Harmful algal blooms (HABs) are common in Monterey Bay, CA, and have resulted in repeated closures of shellfish fisheries and the poisoning and death of marine mammals. In the majority of instances, HAB events in this region are first detected by the presence of sick or dying animals. The phrase "cryptic blooms" was adopted to denote the appearance of poisoning at higher trophic levels with no prior evidence of a large phytoplankton bloom. We hypothesize that the onset of many HAB events goes undetected because the bloom is initially concentrated in discrete thin subsurface layers in the water column that are easily missed by conventional sampling and monitoring methods. In this paper, we report on the detection and monitoring of a subsurface layer of phytoplankton in northern Monterey Bay, CA, using a high-resolution, autonomous profiler. This {\textquoteright}thin layer,{\textquoteright} which measured from 10 cm to 3 m in thickness (85\%< 2 m; 54\%< 1 m), persisted over a 7-day period near the base of the pycnocline. The phytoplankton assemblage in the layer was primarily composed of a multi-species assemblage of Pseudo-nitzschia including the toxin-producing species Pseudo-nitzschia australis. Concentrations of toxic phytoplankton (P. australis), cyanobacteria, and bacteria in the layer were significantly higher than outside the layer (P<0.05). Counts of total Pseudo-nitzschia spp. showed similar levels of enrichment in the layer compared to outside the layer. Our findings indicate that, when monitoring for HABs, it is critical to sample at scales appropriate to resolve thin layers. Thin layers have been identified as a common recurrent feature in a variety of coastal systems, suggesting that the use of autonomous high-resolution vertical profilers coupled with targeted sampling, could allow more timely detection of HABs in many coastal environments.},
	keywords = {california, Coastal waters, cryptic bloom, domoic acid, fjord, harmful algal bloom, physical processes, plankton, sea, thin layer},
	isbn = {1559-2723},
	url = {<Go to ISI>://000253696500014},
	author = {McManus, M. A. and Kudela, R. M. and Silver, M. W. and Steward, G. F. and Donaghay, P. L. and Sullivan, J. M.}
}
@article {596,
	title = {Development of a logistic regression model for the prediction of toxigenic Pseudo-nitzschia blooms in Monterey Bay, California},
	journal = {Marine Ecology-Progress Series},
	volume = {383},
	year = {2009},
	note = {455KATimes Cited:0Cited References Count:69},
	pages = {37-51},
	abstract = {Blooms of the diatom genus Pseudo-nitzschia have been recognized as a public health issue in California since 1991 when domoic acid, the neurotoxin produced by toxigenic species of Pseudo-nitzschia, was first detected in local shellfish. Although these blooms are recurring and recognized hazards, the factors driving bloom proliferation remain poorly understood. The lack of long-term field studies and/or deficiencies in the scope of environmental data included within them hinders the development of robust forecasting tools. For this study, we successfully developed predictive logistic models of toxigenic Pseudo-nitzschia blooms in Monterey Bay, California, from a multi-project dataset representing 8.3 yr of sampling effort. Models were developed for year-round (annual model) or seasonal use (spring and fall-winter models). The consideration of seasonality was significant: chlorophyll a (chl a) and silicic acid were predictors in all models, but period-specific inclusions of temperature, upwelling index, river discharge, and/or nitrate provided significant model refinement. Predictive power for {\textquoteright}unknown{\textquoteright} (future) bloom cases was demonstrated at >= 75\% for all models, out-performing a chl a anomaly model, and performing comparably to, or better than, previously described statistical models for Pseudo-nitzschia blooms or toxicity. The models presented here are the first to have been developed from long-term (>1.5 yr) monitoring efforts, and the first to have been developed for bloom prediction of toxigenic Pseudo-nitzschia species. The descriptive capacity of our models places historical and recent observations into greater ecological context, which could help to resolve historical alternation between the implication of freshwater discharge and upwelling processes in bloom dynamics.},
	keywords = {Bacillariophyceae, diatom pseudonitzschia-australis, domoic acid, domoic acid production, environmental-conditions, gulf-of-mexico, harmful algal bloom, harmful algal blooms, logistic regression, phytoplankton monitoring, predictive model, Pseudo-nitzschia, santa-barbara channel, sea lions, seasonal fluctuations, zalophus-californianus},
	isbn = {0171-8630},
	url = {<Go to ISI>://000266756800004},
	author = {Lane, J. Q. and Raimondi, P. T. and Kudela, R. M.}
}
@article {603,
	title = {Empirical models of toxigenic Pseudo-nitzschia blooms: Potential use as a remote detection tool in the Santa Barbara Channel},
	journal = {Harmful Algae},
	volume = {8},
	number = {3},
	year = {2009},
	note = {409LFTimes Cited:2Cited References Count:55},
	month = {Feb},
	pages = {478-492},
	abstract = {The Santa Barbara Channel, CA is a highly productive region where wind-driven upwelling and mesoscale eddies are important processes driving phytoplankton blooms. In recent years, the spring bloom has been dominated by the neurotoxin-producing diatom, Pseudo-nitzschia spp. In this paper, we relate a 1.5-year time series of Pseudo-nitzschia spp. abundance and domoic acid concentration to physical, chemical, and biological data to better understand the mechanisms controlling local Pseudo-nitzschia spp. bloom dynamics. The data were used to define the ranges of environmental conditions associated with Pseudo-nitzschia spp. bloom development in the Santa Barbara Channel. The time series captured three large toxic events (max. particulate domoic acid concentration, pDA similar to 6000 ng L-1; max. cellular domoic acid concentrations, cDA similar to 88 pg cell(-1)) in the springs of 2005-2006 and summer 2005 corresponding to bloom-level Pseudo-nitzschia spp. abundance (>5.0 x 10(4) cells L-1). In general, large increases in Pseudo-nitzschia spp. abundance were accompanied by increases in cDA levels, and cDA peaks preceded pDA peaks by at least one month in both the springs of 2005 and 2006. Statistical models incorporating satellite ocean color (MODIS-Aqua and SeaWiFS) and sea surface temperature (AVHRR) data were created to determine the probability that a remotely sensed phytoplankton bloom contains a significant population of toxic Pseudo-nitzschia spp. Models correctly estimate 98\% of toxic bloom situations, with a 7-29\% rate of false positive identification. Conditions most associated with high cDA levels are low sea surface temperature, high salinity, increased absorption by cDOM (412 nm), increased reflectance at 510/555 nm, and decreased particulate absorption at 510 nm. Future efforts to merge satellite and regionally downscaled forecasting products with these habitat models will help assess bloom forecasting capabilities in the central CA region and any potential connections to large-scale climate modes. (C) 2008 Elsevier B.V. All rights reserved.},
	keywords = {australis, california, characteristic patterns, circulation, coast, domoic acid, domoic acid production, environmental-conditions, global ocean, habitat models, north pacific-ocean, phytoplankton, Pseudo-nitzschia, remote-sensing, southern california bight},
	isbn = {1568-9883},
	url = {<Go to ISI>://000263506500011},
	author = {Anderson, C. R. and Siegel, D. A. and Kudela, R. M. and Brzezinski, M. A.}
}
