Gca. Duineveld et al., THE BENTHIC INFAUNA AND BENTHIC RESPIRATION OFF THE BANC-DARGUIN (MAURITANIA, NORTHWEST AFRICA), Hydrobiologia, 258, 1993, pp. 107-117
In May 1988, a study was made of the benthic community structure and b
enthic respiratory activity along two transects across the Mauritanian
shelf off Banc d'Arguin. The main emphasis of the present paper is pu
t on the macrobenthos, but results of a gross analysis of the meibenth
os are discussed as well. Macrofaunal and meiofaunal density showed no
consistent decrease with distance from the shore. The composition of
the macrofauna taxa appeared to be closely correlated with sediment pa
rameters and less so with depth. The highest macrofaunal biomass was f
ound at the northern edge of the Banc d'Arguin, and the lowest biomass
along the outer shelf. The biomass levels on the shelf match the ones
reported for the northern Cap Blanc area where, in contrast to the se
asonal upwelling in the investigated area, upwelling takes place all y
ear round. Benthic respiration rates on the offshore shelf were relati
vely high at the nearshore stations and low near the shelf break. Expe
rimental evidence suggests that the low O2 levels in the upwelling wat
er covering part of shelf, inhibited benthic respiration. The high res
piratory activity at some northern inshore stations coincided with the
presence of oxygen-rich coastal water. In this area benthic respirati
on surpassed the level previously reported for the enriched Cap Blanc
area. On the basis of our respiration data, an estimate is made of the
total carbon demand of the benthic community on the shelf in May and
this quantity is compared with the measurements of daily primary produ
ction.