Publication Date:
2019-03-21
Description:
Macrofaunal sediment reworking activity is a key driver of ecosystem functioning in marine systems. So far
sediment reworking rates can only accurately be assessed by measurements as inference from community
parameters is limited. In this case study we test the applicability of 2-D optical florescent sediment profile
imaging (f-SPI) on multi corer type incubation cylinders. f-SPI has to date been applied to flat-surfaced (i.e.
rectangular) cores only, while multi corer type incubation cylinders were analyzed by the spatially low resolved
and invasive slicing technique. Here we apply both methods to cylindrical sediment cores (10 cm diameter).
Cores were taken from by two common communities (i.e. Nucula-community and Amphiura-community) in the
southern German Bight. Both f-SPI and the slicing technique showed similar vertical luminophore profiles.
However the slicing technique found no significant differences between the two communities, whereas f-SPI
showed significant differences for all investigated sediment reworking parameters: sediment reworking rate,
non-locality index, mean weighted luminophore depth, and the maximal luminophore depth. Consequently, this
may lead to different conclusions about the sediment reworking behaviors of the two communities. Likely the
slicing method failed to detect significant differences between the Nucula- and Amphiura-community, owing to
insufficient spatial accuracy. The f-SPI method, on the other hand, did not capture the full extent of maximal
sediment reworking depth due to wall-effects. We conclude that both methods have specific drawbacks and
advantages. While slicing is preferable when focusing on the absolute maximal sediment reworking depth
especially with predominantly sessile communities, f-SPI is better suited to capture general sediment reworking
patterns of most other communities. We demonstrate further that the bias, which is introduced by the distortion
effect on imaging due to optical perspective and cylinder wall curvature of rounded cylinders using f-SPI, is
negligible. Accordingly our results indicate that the distortion effects by curvature of the rounded cylinder walls will not cause underestimations of sediment reworking parameters in the f-SPI approach. Consequently f-SPI is suitable for the investigation of sediment reworking in natural communities by means of multi corer type
samples.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
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isiRev
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