Kinneret Algae Atlas

Phylum: Dinoflagellata
Class: Dinophyceae
Order: Peridiniales
Habitat: plankton, pelagial
Distinctive features: mixotroph, heavily grazed by zooplankton, capable of using bicarbonate for photosynthesis.
Organization: flagellated single cells
Color: yellow to golden-brown
Cell shape: near-sphere
Cell diameter (D): 29 – 40.5 µm, median: 34 µm (N=580)
Cell length (L): 32 – 44 µm, median: 39 µm (N=262)
Cell biovolume: 14,000 – 40,500 µm³, median: 21,300 µm³. Larger cell size in winter, smaller in summer (see Fig. 2b).
Biovolume equation: V, µm³ = 0.9405 D²·⁸⁵⁹⁶ (regression eqn. based on >500 measurements of both D and L with V computed for a prolate sphaeroid).

Morphological features

Peridiniopsis borgei is the largest of several species of Peridiniopsis, Durinskia, Glechodinium, Naiadinium, and Parvodinium occurring in the lake. Its shape is almost a sphere (Plate 1), with the cingulum, or girdle, markedly transversing it in the middle. The epitheca is conical with a mouth-like tip at the apex (highest point), the hypotheca is broadly rounded. Sometimes the hypotheca has an extension at its bottom end, like a small “foot”. Chloroplasts are numerous and ribbon shaped. Diagnostic features seen with electron microscopy: the sulcus slightly extends into the epitheca, it widens in the hypotheca, it does not reach the antapex (Plate 1 d,e). Sulcal margins sometimes have raised edges.

Plate 1. Peridiniopsis borgei. Light microscope (a-c) and SEM photos (d-f) showing the diagnostic features of near-sphere shape, distinct cingulum, single “foot” in some but not all cells, pointed tip at the apex, ventral sulcus extending slightly into the epitheca, mostly into the hypotheca but not reaching the antapex (d, e), and dorsal view (f). Light microscope photos: Alla Alster; SEM photos: Barbara Hickel.

Ecology

Peridiniopsis borgei is one of several subdominant dinoflagellates, common in spring each year (Fig. 1). It reaches peak abundance of several tens of cells per ml in May-June and remains present in the plankton until October (Fig. 2a). The contribution of Peridiniopsis borgei to total biomass was usually < 10% but on rare occasions it reached 40%. Peridiniopsis borgei shows an annual cycle also of cell size (Fig. 2b). Its cellular volume increases during the bloom increase phase, reaching maximum size (diameter: 37 µm, volume: 31,000 µm³) before reaching peak cell abundance, then cell size declines to a minimum (diameter: 27 µm, volume: 11,000 µm³) at about the same time as the minimum cell abundance. Peridiniopsis borgei is potentially capable of using HCO₃ as C source for photosynthesis when pH is high and CO2 availability low (Berman-Frank et al. 1994). It is an important food source for zooplankton in late spring, after the decline of Peridinium gatunense (Zohary et al. 1994).

Environmental conditions

Peridiniopsis borgei biomass > 5 g m⁻² occurred more frequently but not exclusively at pH > 8.5, alkalinity < 130 mg L⁻¹, chloride <280 mg L⁻¹, at water temperatures >17 C (Fig. 3), and over the full range of TDP and calcium concentrations, when the lake was stratified (not shown).

Additional figures

Fig. 1. Time series of Peridiniopsis borgei biomass in Lake Kinneret, 1978-2020.

Fig. 2. The annual cycle of Peridiniopsis borgei in Lake Kinneret, 1978-2020: (a) cell abundance, (b) cell size, as volume per cell.

Figure 3. Peridiiniopsis borgei biomass vs. selected environmental parameters from Lake Kinneret. Based on data for 1978-2020.

Cite this record as: Tamar Zohary, Alla Alster. 7 May 2026. Electronic publication. Israel Oceanographic & Limnological Research. https://kinneret-algae-atlas.org/ Searched on —.

Peridiniopsis borgei Lemmermann 1904

Morphological features

Ecology

Environmental conditions

Additional figures

Further reading