ABSTRACT: Several experiments were carried out to provide new information on the use of the ¹⁴C formaldehyde technique in deposit-feeding studies. Our results show that: (1) uptake and stability of labelling vary with species and types of detritus, (2) there are significant differences between the labelling stabilities of uniformly and ¹⁴C formaldehyde labelled diatoms, (3) the use of uniformly and ¹⁴C formaldehyde labelled detritus derived from Pavlova lutheri results in very similar ingestion rates and absorption efficiencies by Abra ovata, (4) ingestion rates and absorption efficiencies of Abra ovata fed on 11 macrophytobenthic types of detritus labelled with ¹⁴C formaldehyde are consistent with the literature (negative relationship between ingestion and protein content, and between absorption and phenolic content), and (5) absorption efficiencies recorded for ¹⁴C formaldehyde labelled sediment trap materials collected at different periods of the year correlate negatively with gross sedimentation rates. These results support the use of the ¹⁴C formaldehyde technique with monospecific detritus. The relative values of absorption efficiencies recorded for heterogeneous detritus also seem consistent. However, it is stressed that the exactitude of the absolute values of these absorption efficiencies is yet to be proven.

KEY WORDS: Radiotracer techniques . Sedimentary organic matter . Absorption efficiency . Deposit-feeder . ¹⁴C formaldehyde

Published in MEPS Vol. 127 (1995) on November 2
ISSN: 0171-8630. Copyright © Inter-Research, Oldendorf/Luhe, 1995