Enhanced benthic activity in sandy sublittoral sediments: Evidence from ¹³C tracer experiments

Figures & data

Figure 1.  Incorporation of algal ¹³C into bacterial fatty acids (µg ¹³C m⁻²) (sampling depth 0–12 cm) from the on-board incubations of 12, 30 and 132 h and the 32 h in situ experiments. The bars represent the mean value and the error bars depict the higher value of two replicates.

Figure 2.  Incorporation (µg ¹³C m⁻²) into bacteria versus sediment depth from the on-board incubations of 12, 30 and 132 h and the 32 h in situ experiments. The bars represent the mean value and the error bars indicate the range of two replicates.

Figure 3.  Total uptake (µg ¹³C m⁻²) of label into macrofauna versus sediment depth during the 12, 30 and 132 h on-board incubations and the 32 h in situ experiment. The bars indicate the mean value and the error bars depict the standard deviation.

Figure 4.  Release of ¹³CO₂ to overlying water (µM) over time for the 12, 30 and 132 h on-board incubations. The symbols indicate the mean value and the error bars depict the range of two parallels.

Figure 5.  Porewater ¹³CO₂ (µM) versus sediment depth of the 12, 30 and 132 h on-board incubations and the 32 h in situ experiment. The symbols indicate the mean value and the error bars depict the range of two parallels.

Table I. Biomass of macrofauna and bacteria and the recovered label in the different benthic compartments of the two parallels of the 12, 30 and 132 h experiments of the April cruise and the 32 h in situ experiment of the June cruise.

Compartment	Biomass	µg ^13C m^−2 after 12 h		µg ^13C m^−2 after 30 h		µg ^13C m^−2 after 132 h		µg ^13C m^−2 after 32 h (in situ)
Bacteria	April 20.4 g m^−2 ^a	2460	9070	7160	5680	6350	4070
	June 7.6 g m^−2 ^a							2660	1680
Macrofauna	April 243.8 g m^−2 ^b	50	450	2480	1790	4970	830
	June 341.3 g m^−2 ^b							8090	1930
Dissolved Inorganic Carbon (DIC)		1220	600	2770	4330	7880	8410	3360	510
^aFrom Bühring et al. (2005).
^bFrom Kamp & Witte (2005).