Page 113 - Microbial methane cycling in a warming world From biosphere to atmosphere Michiel H in t Zandt

of the postglacial sea-level rise and was quickly capped by rapidly deposited clays and subsequent sand deposits in most instances or directly capped by sand in others.
Figure 2. Photographs and stratigraphy of key sites. A-D) the four sites from which sediments were used to perform 16S rRNA gene-based diversity analysis. These sites lie within the mid and southern North Sea. E-F) the four sites from which sediment was used to study microbial activity. These sites originate from the Doggerbank area. Note the varying y-axes.
Non-erosive contact transitions exist between the peat layer and both the immediate upper and lower sedimentary layers at the majority of sites (17 of a total 20), indicating that no widespread extreme event took place in the period directly prior or subsequent to the Pleistocene-Holocene transition. In most cases, the peat is covered by a clay layer that formed under lagoonal, low- energy conditions and rests conformably on the peat. However, some cores do show erosional contacts (i.e. Fredricksborg NE, Fredricksborg NW, and Dorthea NW sites) at the top of the peat beds that can be associated with marine transgression of the area, likely related to waves or tidal currents. The clay sediment directly above the peat layer at the Vittorio site is approximately 1 m thick and the thickest clay deposit among all sites. The nearby Max
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