Growth of the harmful alga,Prymnesium parvum(Prymnesiophyceae), after gradual and abrupt increases in salinity

Abstract

Prymnesium parvum is a euryhaline, toxin‐producing microalga. Although its abundance in inland waters and growth potential in the laboratory is reduced at high salinity (>20), the ability of inland strains to adjust their growth after long‐term residence in high salinity is uncertain. An inland strain of P. parvum maintained at salinity of 5 in modified artificial seawater medium (ASM‐5) was subjected to the following treatments over five sequential batch culture rounds: ASM‐5 (control); modified ASM at salinity of 30, raised with NaCl; modified ASM at salinity incrementally increased to 30 with NaCl; and Instant Ocean® at salinity of 30 (IO‐30). Exponential growth rate (r) was reduced when salinity was increased from 5 to 30 in ASM but returned to control values during the second round. When salinity was incrementally increased, a reduction in r still occurred when salinity reached 25‐30. Maximum density was reduced at salinity of 30 in ASM upon abrupt transfer or incremental increase, and compensation did not occur. Growth performance in IO‐30 was comparable to control values. In conclusion, (i) long‐term compensation for acute inhibitory effects of high salinity occurred for r but not maximum density, (ii) incremental increases in salinity did not prevent growth inhibition, suggesting the existence of a salinity threshold of 25–30 for onset of salinity stress, and (iii) the presence of a seawater‐like salt mixture prevented growth inhibition by high salinity. These findings provide new insights on P. parvum's long‐term ability to adjust its growth in environments of different salinity and ionic composition.

Extreme genome diversity and cryptic speciation in a harmful algal bloom forming eukaryote

“…We obtained Hi-C scaffolded, highly contiguous genome assemblies of two P. parvum strains from Texas: UTEX 2797 and 12B1. UTEX 2797 was selected for sequencing due to its use in numerous toxicology and physiology experiments of P. parvum ( e.g., 19,20,22,[27][28][29][30][31][32]. However, preliminary analysis of k-mer frequencies revealed that UTEX 2797 displays high sequence-level heterozygosity (Fig.…”

Terrestrial input of herbicides has significant impacts on phytoplankton and bacterioplankton communities in coastal waters

“…is more than 100 nmol L −1 (Pennington and Scott 2001; Weiner et al 2004), which is much higher than the concentrations we used in this study. There may be some unknown mechanisms in these species to compensate for atrazine stress and keep their carbon uptake less affected (Weiner et al 2007; Richardson and Patiño 2021).…”

Toxic Algae in Inland Waters of the Conterminous United States—A Review and Synthesis

“…Lundgren et al [292] looked into biotic factors that may influence bloom formation in Texas estuarine waters and reported that the seasonal composition of planktonic communities may complicate P. parvum's establishment in these waters. Based on these observations, Richardson and Patiño [293] suggested that biotic and abiotic conditions in the upper reach of intertidal zones may be serving as barriers to downstream expansion. Research into these and other possible scenarios could help understand-and maintain-current barriers to the seaward expansion of P. parvum blooms in Texas.…”