Effects of environmental oxygen partial pressure on nauplii respiration rates of the planktonic copepod, Acartia tonsa
ASLO Aquatic Sciences Meeting, Granada, Spain
Copepods, in addition to many other marine organisms, rely on diffusion across their integument to obtain the required oxygen to support growth and regulate metabolic functions. This diffusion rate is determined by the pressure gradient of oxygen between the organism and the dissolved oxygen in the water. Hypoxia (< 2 mg L-1 dissolved oxygen concentration) has become increasingly prevalent in coastal waters including the Chesapeake Bay, threatening populations of the common planktonic copepod, Acartia tonsa. Despite behavioral adaptation of adults, copepod eggs commonly sink into hypoxic or anoxic zones. Therefore, it is possible that eggs and early stage nauplii are forced to maintain a minimal respiration rate in order to survive these low oxygen conditions. In order to predict the population success of A. tonsa species, we studied the effect of environmental oxygen partial pressure on stage I-II nauplii respiration rates. Our preliminary data suggests that below a threshold level (P crit) nauplii respiration may decrease with lower oxygen partial pressure. Our presentation will explore how temperature and oxygen concentration determine oxygen availability and demand in copepod nauplii.