The Correlation between Prorocentrum donghaiense Blooms and the Taiwan Warm Current in the East China Sea - Evidence for the “Pelagic Seed Bank” Hypothesis

PLOS ONE, Dec 2019

During the last two decades, large-scale high biomass algal blooms of the dinoflagellate Prorocentrum donghaiense Lu have occurred frequently in the East China Sea (ECS). The role of increasing nutrient concentrations in driving those blooms is well-established, but the source population that initiates them is poorly understood. We hypothesized that the front of Taiwan Warm Current (TWC) may serve as a ‘seed bank’ that initiates P. donghaiense blooms in the ECS, as the physiochemical conditions in the TWC are suitable for the growth of P. donghaiense. In order to test this hypothesis, two surveys at different spatio-temporal scales were conducted in 2010 and 2011. We found a strong correlation in space and time between the abundance of P. donghaiense and the TWC. The spatial extent of the P. donghaiense bloom coincided with the TWC front in both 2010 and 2011. During the early development of the blooms, P. donghaiense concentration was highest at the TWC front, and then the bloom mass shifted inshore over the course of our 2011 survey. The TWC also moved inshore, albeit after the appearance of P. donghaiense. Overall, these results support our hypothesis that P. donghaiense blooms develop from the population at the TWC front in the ECS, suggesting the role of the ocean current front as a seed bank to dinoflagellate blooms.

A PDF file should load here. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a PDF plug-in installed and enabled in your browser.

Alternatively, you can download the file locally and open with any standalone PDF reader:

https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0064188&type=printable

The Correlation between Prorocentrum donghaiense Blooms and the Taiwan Warm Current in the East China Sea - Evidence for the “Pelagic Seed Bank” Hypothesis

et al. (2013) The Correlation between Prorocentrum donghaiense Blooms and the Taiwan Warm Current in the East China Sea - Evidence for the ''Pelagic Seed Bank'' Hypothesis. PLoS ONE 8(5): e64188. doi:10.1371/journal.pone.0064188 The Correlation between Prorocentrum donghaiense Blooms and the Taiwan Warm Current in the East China Sea - Evidence for the ''Pelagic Seed Bank'' Hypothesis Xinfeng Dai 0 Douding Lu 0 Weibing Guan 0 Ping Xia 0 Hongxia Wang 0 Piaoxia He 0 Dongsheng Zhang 0 Senjie Lin, University of Connecticut, United States of America 0 State Key Laboratory of Satellite Ocean Environment Dynamics, The Second Institute of Oceanography, SOA , Hangzhou , China During the last two decades, large-scale high biomass algal blooms of the dinoflagellate Prorocentrum donghaiense Lu have occurred frequently in the East China Sea (ECS). The role of increasing nutrient concentrations in driving those blooms is well-established, but the source population that initiates them is poorly understood. We hypothesized that the front of Taiwan Warm Current (TWC) may serve as a 'seed bank' that initiates P. donghaiense blooms in the ECS, as the physiochemical conditions in the TWC are suitable for the growth of P. donghaiense. In order to test this hypothesis, two surveys at different spatio-temporal scales were conducted in 2010 and 2011. We found a strong correlation in space and time between the abundance of P. donghaiense and the TWC. The spatial extent of the P. donghaiense bloom coincided with the TWC front in both 2010 and 2011. During the early development of the blooms, P. donghaiense concentration was highest at the TWC front, and then the bloom mass shifted inshore over the course of our 2011 survey. The TWC also moved inshore, albeit after the appearance of P. donghaiense. Overall, these results support our hypothesis that P. donghaiense blooms develop from the population at the TWC front in the ECS, suggesting the role of the ocean current front as a seed bank to dinoflagellate blooms. - Funding: This study was supported by CEOHAB-II National 973 Program (2010CB428702; 2010CB428704), National Science Foundation (41176141), Grant from the scientific research fund of the Second Institute of Oceanography, SOA (SZ1040), Foundation of Key Laboratory of Integrated Marine Monitoring and Applied Technologies for Harmful Algal Blooms, SOA (MATHAB20100310) and Zhejiang Provincial Natural Science Foundation (Y5110185). 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. Large-scale high biomass algal blooms of the dinoflagellate Prorocentrum donghaiense Lu have occurred frequently in the East China Sea (ECS) over the last two decades. These blooms are massive, sometimes extending over thousands of square kilometers, and can persist for nearly one month [1,2]. The blooms are considered to be driven by increasing nutrient inputs from the Changjiang River (the largest river in China) and upwelling [35]. One aspect of the P. donghaiense bloom that is poorly understood is its initiation. A hypothesis is that a pelagic seed bank of low number of P. donghaiense cells offshore may act as an inoculum. The hypothesis, proposed by Smayda (2002), postulates that algal cells that have accumulated at ocean current fronts may act as bloom inoculums in upwelling zones [6]. The proposed mechanism is in contrast to the initiation mechanism that has been described for cyst-forming dinoflagellate species (e.g. Alexandrium fundyense) that are inoculated through the germination of their benthic cysts [7,8]. No such cyst stage has been described for P. donghaiense [4]. Therefore its initiation is more likely to rely on mechanisms like the pelagic seed bank that deliver vegetative cells to nutrient rich waters like upwelling zones. There is an upwelling belt in the ECS, about 40 km in width between the 20 m and 50 m isobaths and parallel to the Zhejiang coast line [911]. The upwelling is mainly induced by the continental slope and the Taiwan Warm Current (TWC) [12,13]. As a branch of the Kuroshio Current (KC), the TWC is characterized by a high temperature and salinity, making it suitable for the survival and growth of P. donghaiense cells even in winter time [14,15]. In this study, we tested the pelagic seed bank hypothesis for the initiation of P. donghaiense blooms in the ECS via introduction from the TWC front. Two surveys at different spatio-temporal scales were conducted in 2010 and 2011 (Fig. 1) with the objective of delimiting the TWC and the extent and abundance of P. donghaiense cells. The bloom pattern and development were examined in the surveys. P. donghaiense cells were present above our detection limit of 2 cells/L at 38 of 41 stations during the 2010 comprehensive survey. The number of dinoflagellate species recorded varied from 1 to 9 (including P. donghaiens (...truncated)


This is a preview of a remote PDF: https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0064188&type=printable

Xinfeng Dai, Douding Lu, Weibing Guan, Ping Xia, Hongxia Wang, Piaoxia He, Dongsheng Zhang. The Correlation between Prorocentrum donghaiense Blooms and the Taiwan Warm Current in the East China Sea - Evidence for the “Pelagic Seed Bank” Hypothesis, PLOS ONE, 2013, 5, DOI: 10.1371/journal.pone.0064188