Chrysochromulina parva – Kinneret Algae Atlas

Phylum: Haptophyta
Class: Coccolithophyceae
Order: Prymnesiales
Habitat: plankton, pelagic/littoral
Distinctive features: A tiny flagellated species that is seasonally extremely abundant (thousands of cells/mL), probably mixotroph, heavily grazed by zooplankton.
Organization: flagellated single cells
Color: yellow to golden-brown
Cell shape: spheroid
Cell diameter (D): 2.9 – 5.2 μm, median: 3.9 μm (N=100).
Cell biovolume: 13 – 76 μm³, median: 34 μm³.
Biovolume equation: Sphere V, μm³ = 4/3 π *(D/2)³.

Morphological features

This species comprises the smallest (3 - 5 μm diameter), but very common flagellates of Lake Kinneret (Plate. 1). Cells have a , spheroid shape except when dividing (Plate 2A), with 2 of equal or near-equal length, 1 (Plate 2B), 2 chloroplasts, 2 contractile vacuoles, and a (Plates 1, 2). The flagella are much longer than the cell. During swimming, one flagellum is directed forward, whereas the other trails behind. The haptonema that may be mistaken for a third flagellum, is a thread-like organelle used for attachment and catching prey. It is thinner and more delicate than the flagella and rarely seen under a light microscope, because it often contracts and hides against the cell wall. During cell division there is a stage when the two daughter cells are still contained within the same cell wall thus the cell seems particularly wide and with 4 flagella (Plate 2A). Skyua, who first described Erkenia subaequiciliata in 1948, didn’t see its haptonema and placed it with the Chrysophyta, although in all other attributes it resembled the haptophyte Chrysochromulina parva Lackey 1939. With more advanced microscopy it was shown in the 1960s that the two species are identical, and the earlier name, Chrysochromulina parva, took over.

Plate 1. Chrysochromulina parva from Lake Kinneret. Note the small, spherical cell shape and the shape of the chloroplasts. A flagellum (only 1 of 2) is seen in the uppermost specimen.

Plate 2. Hand drawing of Erkenia subaequiciliata Skuja= Chrysochromulina parva Lackey: A. by Skuja 1957, showing the life-cycle of this bi-flagellated species, including its division into two daughter cells (33-36). B. by Lackey 1939, showing the haptonema (pointed upwards in 1,2,3) as well as other details. 1 General structure. 2 lateral view. 3 Cell with round chromatophores, 4. Cross-section showing middle depression.

Ecology

Chrysochromulina parva is the smallest flagellated species occurring in Lake Kinneret. At times it is incredibly abundant, reaching concentrations of > 1000 cells mL^-1; an all-time maximum of 11,900 cells mL^-1 was recorded in April 2019 (Fig. 1). Despite their high abundance, their minute size makes their contiribution to total phytoplankton biomass usually negligible, on average only 0.4%. The max biomass contribution ever recorded was 7.9 g m^-2 and 13% of the total biomass. Chrysochromulina parva is abundant in winter – spring, it is rare or completely absent from the water column in the summer and re-appears in the fall (Fig. 2).

Environmental conditions

occurs at the full range of temperatures, water levels, , chloride, , Ca and nitrate concentrations recorded in Lake Kinneret. Higher abundances were restricted to a relatively narrow range of long wave radiation, between 325-375 Watt m^-2, to overall low chlorophyll concentration (i.e. not during major blooms of other species), at DON < 0.4 mg L^-1, NH₄ < 0.1 mg L^-1, organic N around 0.5 mg L^-1, pH in the range of 8-9 and Secchi depth between 1-4 m (Fig. 3).

Additional figures

Figure 1. Time series of Chrysochromulina parva cell abundance in Lake Kinneret, 1970-2020.

Figure 2. The annual pattern of water column cell abundance of Chrysochromulina parva, based on data for 1978-2020. Statistics shown are: median – middle line; 25th to 75th percentiles – box content; 90th and 10th percentiles - top and bottom bars, respectively.

Figure 3. Chrysochromulina parva abundance (cells mL^-1) vs. selected environmental parameters recorded at the site and time of sampling, showing indifference to temperatue and nitrate but tendency for higher cell concentrations at lower chlorophyll and DON concentrations.

Cite this record as: Dr. Tamar Zohary, Dr. Alla Alster. 16 June 2026. Electronic publication. Israel Oceanographic & Limnological Research. https://kinneret-algae-atlas.org/ Searched on —.