How do marine nematodes cope w ith extrem e tem peratures and fluctuations? Vafeiadou Anna-M aria12, Chariton C h in tiro g lo u 2 and Tom M oens1 1 Marine Biology Section, Ghent University, Krijgslaan 281 /S8, 9000 Ghent, Belgium E-mail: am.vafeiadou@ qmail.com 2 Biology Departm ent, A risto tle U niversity o f Thessaloniki, 54124 Thessaloniki, Greece Increased tem perature flu ctu a tio n s and m axim a have been reported the last decades as main consequences o f global clim ate change. In inte rtid a l areas, the com bination o f episodically elevated w ater tem perature and short-term exposure to high air tem perature at low tide may exceed the tolerance o f some organism s, causing local extinctio ns. A lth ou g h organism s develop p la sticity tow ards stress, extrem e change o f the environm ental co nd itio ns can eventually a lter population dynamics. Marine nematodes are the m ost abundant benthic organism s, and due to th e ir short life span, th ey are an excellent taxon fo r the investigation o f benthic responses to such stress conditions. T he ir response w ill be exam ined at m ultiple levels: from individuals to populations and com m unities, including also interactions among species a n d /o r tro p h ic levels. Specifically, the effects o f short-term (daily/w eekly) tem perature flu ctua tion s on nematode populations and individuals, w ith in the same or between adjacent tro p h ic levels w ill be exam ined. In a dd itio n, the effects o f tem perature changes on the ecology o f marine nematodes, and in particular th e ir behavior, w ill be investigated w ith in vivo m icrocosm experim ents. Specifically, we focus on the m oving a b ility and the food selectivity o f three closely related nematode species which d iffe r in th e ir tolerance to tem perature flu ctu a tio n s and extrem es to detect any effects due to flu ctu a tin g tem perature. - 1 06 -