title used in learnabout sections of A SNAIL'S ODYSSEY
  Foods & feeding
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  Absorption of DOM

An example of a study on absorption of DOM is presented here, while research studies on SUSPENSION-FEEDING and DEPOSIT-FEEDING are considered elsewhere.

NOTE Dissolved Organic Matter, including amino acids, fatty acids, and other substances. Also referred to as DOC (dissolved organic carbon)

Research study 1

drawing of a kelp plant Macrocystis integrifolia with a frond bagged to receive injection of radio-labelled substance for a study in translocation of DOM to tubeworms Schizobranchia insignisTubeworms Schizobranchia insignis often co-occur in beds of large kelp Macrocystis integrifolia. Studies at the Bamfield Marine Sciences Centre, British Columbia show that 14C-labelled carbon exuded by kelps can be absorbed or eaten and presumably used in the worms' own nutrition.  The study is of special interest in that all experiments are done in plastic bags in situ using SCUBA. Selected fronds of the kelp are bagged and injected with aliquots of Na214CO3 (see drawing on Right). After 48h the bags are removed and contents assayed for labelled material. After washing the fronds to remove residual isotope, they are re-bagged with live worms, again injected with isotope, left for 24h, and taken to the laboratory for tissue analysis.  In all cases, the worms are found to accumulate 14C-label to levels about 14-fold greater than untreated controls. The exuded material may be in the form of dissolved carbon photograph of a mixed cluster of sabellid tubeworms including Schizobranchia insignis (lower left), Eudistylia polymorpha (centre, left), and Eudistylia vancouveri (solitary, Left)or suspended particulate carbon, although which form is used by the worms is not known. The authors conclude by stating that their study is the first to show in situ accumulation of algal extracelluar products by a free-living marine invertebrate. Fankboner & Druehl 1976 Specialia 15: 1391.


Mixed cluster of sabellid tubeworms. Several specimens of
Schizobranchia insignis
are located at the lower Left of
the photo, a few Eudistylia polymorpha are scattered
throughout (see the tan-coloured individual near the
centre of the photo), and a single Eudistylia vancouveri
is located at the Left centre of the photo 0.2X