Preface The expedition ARK XIX/3 with the German icebreaking RV ...

C. 7 Activity and biomass of the small biota
Schewe, I., Hasemann, C., Kanzog, C., Kolar, I., Soltwedel, T.
Benthic deep-sea ecosystems are fuelled by the input of organic matter sinking vertically
through the water column or being advectively transported. Sediment-bound
chloroplastic pigment equivalents, CPE (i.e. chlorophyll a plus degradation products)
have been determined to quantify such an organic matter input from primary production.
Differences in activities and biomass within the sediment samples were assessed by a
series of biochemical assays commonly used in ecological investigations of the deep
sea. To evaluate bacterial exo-enzymatic activities, esterase turnover rates were
determined with the fluorogenic substrates fluorescein-di-acetate (FDA). Rather labile
macro-molecules like phospholipids were analyzed as indicators for 'living biomass', i.e.
small sediment-inhabiting organisms. More stable compounds like particulate proteins
were determined to estimate the bulk of 'living' plus 'dead biomass', i.e. organisms and
the proportion of detrital organic matter in the sediments.
Investigations as described above were performed with sediments sampled by means of
a multicorer (MUC) or ROV. Other sediment samples came from colonisation
experiments with soft sediments performed with moored trays (see Chapter C. 14).
Biochemical analyses estimating heterotrophic activity in the uppermost centimeters of
the sediments were done immediately on board to avoid losses in activity during
storage. Determinations of chloroplastic pigments were carried out on board, whereas
sediments for all the other biochemical analyses and investigations on bacterial
communities were preserved and stored for later analyses at the home institute.
C. 8 Notes on benthic mega-/epifauna and small-scale habitat diversity in the longterm
observation area
Juterzenka, K. v.
The sediment-water interface in the central “Hausgarten” area, which is visited for the
third time by means of the ROV “Victor 6000”, is shaped by a variety of biogenic
structures. These structures enhance the three-dimensional small-scale heterogeneity at
the deep seafloor. Therefore their abundance and effects on different elements of
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