Aquatic Sciences Meeting, Albuquerque 2001

CS41 Phytoplankton: Nutrient Dynamics and Physiology

Date: Friday, February 16, 2001, Time: 10:30:00 AM

Location: Galisteo

Garneau, M, , Université du Québec à Rimouski, Rimouski, Canada, mariegar@globetrotter.net

Gosselin, M, , Université du Québec à Rimouski, Rimouski, Canada, michel_gosselin@uqar.uquebec.ca

Legendre, L, , Station Zoologique, Villefranche-sur-Mer, France, legendre@obs-vlfr.fr

Klein, B, , Université Laval, Québec, Canada, bert.klein@giroq.ulaval.ca

Leblanc, B, , Université Laval, Québec, Canada, bernard.leblanc@giroq.ulaval.ca

VARIATIONS OF THE NITROGEN UPTAKE RATE BY PHYTOPLANKTON IN THE NORTH WATER (NORTHERN BAFFIN BAY) IN AUTUMN 1999

Nitrogen uptake rates were determined along five transects in the North Water (NOW) during late summer (27 August-10 September) and early autumn (11 September-1 October) 1999. The measurements of the ratios of the uptake of ammonium and nitrate at high and low concentrations of these substrates revealed that the phytoplankton was nitrogen-deficient. Overall, the uptake rates of nitrate, ammonium and urea decreased between the two sampling periods. In late summer, there was no difference in the uptake rates between the Canadian side and the Greenland side of the NOW. However, in early autumn, the mean nitrate uptake rate was higher on the Greenland side (0.129 mmol N m-2 h-1) than on the Canadian side (0.058 mmol N m-2 h-1). On both sides, the northernmost stations (>78 deg. N) showed the highest values. For the whole sampling period, the f-ratio (i.e. ratio of new to total nitrogen production) of the northern part was 0.53, while it was 0.39 for the entire region. The results indicate that total and new production in northern Baffin Bay is substantial in late summer-early autumn.

This Session Listing

Aquatic Sciences Meeting, Albuquerque 2001

Quicklinks