Morphology and growth characteristics of Chrysochromulina species (Haptophyceae = Prymnesiophyceae) isolated from New Zealand coastal waters

Abstract

Chrysochromulina acantha, C. hirta, C. pachycylindra, and C. cf. polylepis (Haptophyceae = Prymnesiophyceae) are new records, based on transmission electron microscopy, for New Zealand coastal waters. The morphology and growth characteristics of C. acantha and C. hirta, and of C. simplex and C. ericina (also New Zealand isolates), are described. C. ericina of the present study has a shorter haptonema (12–24 urn; non‐coiling), larger plate and spine scales, and fewer spine scales (with broader bases), than northern hemisphere isolates. Scales of C. simplex fit the emended type description, whereas the large spine scales of C. hirta are shorter (≤ 11 μm) than the type description (20–30 μm). C. ericina and C. hirta fall into a temperate (15–20°C), and C. acantha and C. simplex into a sub‐tropical (20–25°C), temperature group. All species tested grew well in brackish salinities (c. 23 through to 36); C. hirta grew optimally at a salinity of 23. All tolerated 25–150 umol m⁻² s⁻¹ photon flux and pH of 7.5 to c. 8.4. C. acantha had significantly faster growth rates (doublings d⁻¹) with nitrate than with urea or ammonium chloride as nitrogen source, and C. hirta with urea and ammonium chloride rather than with nitrate; none required selenium. None of the species tested was toxic to Artemia salina. C. ericina and C. acantha were phagotrophic. Calcofluor assisted in the identification of C. quadrikonta from other spine‐bearing species and FITC‐conjugated wheat germ lectin aided differentiation of the Chrysochromulina species from Prymnesium parvum and P. patelliferum.

Keywords:

• Chrysochromulina
• Haptophyceae
• Prymnesiophyceae
• growth
• electron microscopy