The long axis of the lake runs approximately East-West (bottom-left to
top-right in photo). The lake is surrounded by low ridges, is shallow,
and therefore is well mixed by both wind and tide. Vertical profiles show
Ongael Lake is essentially isothermal and isohaline with depth (figure
below) and oxygen maxima and minima therefore are probably attributable
to biological activity. Visibility generally is quite poor, but the Secchi
disk depth exceeds the depth of the lake, and this is reflected in the
occurrence of the photosymbiotic upside-down jellyfish (Cassiopea
sp.) throughout the sandy basin. Mastigias sp. and Aurelia
sp.4 also occur in this lake. However, in contrast to jellyfish populations
in other Ongeim'l Tketau and Big Jellyfish Lake, the populations in Ongael
Lake appear to go through >=1 boom-bust cycles per year.
Profiles show mean ± one standard error
(3 profiles, Oct. 1997 to Jun. 2001)
Arrow indicates Secchi disk depth
(greater than depth of lake)
Chlorophyceae - Caulerpa sertularioides, Cladophoropsis
sp., Halimeda sp.
Teleostei - Amblygobius buanensis, Apogon lateralis, Exyrias puntang,
Scyphozoa - Aurelia
sp.4, Cassiopea sp., Mastigias sp.
Bivalvia - Brachidontes sp.
- Suberites sp.2, Pseudosuberites sp.1, Luffariella
Sources: CRRF unpubl. data