Meeting Abstract
Pelagic red crab, Pleuroncodes planipes, is an important and very abundant component of zooplankton in the Eastern Tropical Pacific Ocean. They inhabit pelagic and benthopelagic zones, with temperatures varying from 10˚C to 28˚C. Similar to other zooplankton species, pelagic red crab make daily migrations to the surface waters to feed. They have also been observed to occasionally aggregate into large swarms on the water surface. Recently, it has been proposed that ammonium supplied by diel vertical migrators plays an important role in ocean nitrogen cycle, since it not only provides nitrogen required for phytoplankton growth, but also fuels bacterial anaerobic ammonium oxidation. In our study, we investigated ammonium excretion rates by P. planipes at 10˚C, 15˚C, 20˚C, and 25˚C to encompass temperature range they experience in their natural habitat. We observed that excretion of ammonium increased with increasing temperature. We also investigated whether this increase was reflected in upregulation of the machinery that enables ammonia transport in this animal. In aquatic crabs, the main site of nitrogenous waste excretion is the gill epithelium, and is mediated by specialised cells that host a suite of ion transporting proteins. Using analytical methods we measured abundance and expression of the key proteins that have been proposed to be involved in ammonium excretion, such as Rhesus protein, Na+/K+-ATPase, Na+/H+-exchanger, and H+-ATPase.
