Jc. Marty et al., PARTICULATE FLUXES OF ORGANIC-COMPOUNDS AND THEIR RELATIONSHIP TO ZOOPLANKTON FECAL PELLETS IN THE NORTHWESTERN MEDITERRANEAN-SEA, Marine chemistry, 46(4), 1994, pp. 387-405
Sediment trap experiments were conducted in the northwestern Mediterra
nean (Ligurian sea) in 1987 in the course of the DYFAMED project. The
particles collected during 9-15 day intervals from February through Ju
ly at 200 m and from April through May at 2000 m depth were analysed f
or organic carbon, nitrogen, fatty acids and n-alkanes. Concentrations
in these particles were compared to those in freshly-produced zooplan
kton fecal pellets collected from several cruises during the same peri
od. In winter, high mass fluxes were encountered at 200 m; the organic
material was characterized by a. relatively high proportion of n-alka
nes and C24 fatty acid which are characteristic of refractory (old) or
ganic matter and a low content of the more labile fatty acids. During
the spring and summer period, fluxes contained undegraded phytoplankto
n and zooplankton material. In the 2000 m trap samples, refractory org
anic matter was still present, but the fresh input was very low and ha
d evidently been consumed in the upper water column. There was no tend
ency toward a higher content in bacterial fatty acid markers in zoopla
nkton fecal pellets and 200 m sediment trap material. Based on the ass
umption that all n-alkanes in trap collections originate from sinking
fecal pellets, end-member calculations indicate that intact zooplankto
n fecal pellets are important contributors to vertical particulate flu
xes at 200 m. The maximum contribution is estimated to be between 10%
(in summer) and 30% (spring) using n-alkane marker concentrations.