Growth and Nitrogen Uptake Kinetics in Cultured Procentrum donghaiense

We compared growth kinetics of Prorocentrum donghaiense cultures on different nitrogen (N) compounds including nitrate (NO3 ), ammonium (NH4 ), urea, glutamic acid (glu), dialanine (diala) and cyanate. P. donghaiense exhibited standard Monod-type growth kinetics over a range of N concentraions (0.5–500 mmol N L for NO3 2 and NH4 , 0.5–50 mmol N L for urea, 0.5–100 mmol N L for glu and cyanate, and 0.5–200 mmol N L for diala) for all of the N compounds tested. Cultures grown on glu and urea had the highest maximum growth rates (mm, 1.5160.06 d 21 and 1.5060.05 d, respectively). However, cultures grown on cyanate, NO3 , and NH4 + had lower half saturation constants (Km, 0.28–0.51 mmol N L). N uptake kinetics were measured in NO3 -deplete and -replete batch cultures of P. donghaiense. In NO3 -deplete batch cultures, P. donghaiense exhibited Michaelis-Menten type uptake kinetics for NO3 , NH4 , urea and algal amino acids; uptake was saturated at or below 50 mmol N L. In NO3 -replete batch cultures, NH4 , urea, and algal amino acid uptake kinetics were similar to those measured in NO3 -deplete batch cultures. Together, our results demonstrate that P. donghaiense can grow well on a variety of N sources, and exhibits similar uptake kinetics under both nutrient replete and deplete conditions. This may be an important factor facilitating their growth during bloom initiation and development in Nenriched estuaries where many algae compete for bioavailable N and the nutrient environment changes as a result of algal growth. Citation: Hu Z, Duan S, Xu N, Mulholland MR (2014) Growth and Nitrogen Uptake Kinetics in Cultured Prorocentrum donghaiense. PLoS ONE 9(4): e94030. doi:10.1371/journal.pone.0094030 Editor: Senjie Lin, University of Connecticut, United States of America Received November 4, 2013; Accepted March 12, 2014; Published April 7, 2014 Copyright: 2014 Hu et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: The authors acknowledge the financial support from the China Scholarship Council to Zhangxi Hu. In addition, this work was supported by NOAA and NSF grants to MRM, and Natural Science Foundation of China (NSFC) (Grant Numbers 40776078, 40876074, 41176104). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. * E-mail: [email protected] (NX); [email protected] (MRM)