The copepod genus Oithona is among the most abundant mesozooplankton in both eutrophic and oligotrophic waters. This paper reports the individual and combined effect of temperature and pH on the development, reproduction success, and feeding preference of the tropical species Oithona rigida. Experiments were conducted at different temperature (28, 30, 31, and 32°C) and pH (7.7, 7.9, and 8.1) conditions. Effects on vital rates were observed for different developmental stages and adult males. Sex ratio varied from near 1:1 at 28°C to almost entirely female at 32°C. Egg production and hatching success were maximum at 30°C and pH at 7.9. O. rigida preferred the motile green alga Dunaliella salina in terms of ingestion rate, feed selectivity, and egg production across all the temperature and pH conditions. Long-term studies are needed to validate the adaptability of this species to a variety of climate impacts.
Khalifa U., Ebenezer V. & Pierson J. J., in press. Elevated temperature and low pH affect the development, reproduction, and feeding preference of the tropical cyclopoid copepod Oithona rigida. International Journal of Environmental Studies. Article (subscription required).
