Rates of oxygen uptake, denitrification, nitrate reduction to ammonia, and sulfate reduction were measured in a Danish estuary over 1.5 yr. In sediments near the sea entrance, O2 and SO?, -reduction dominated and the relative contributions of the 4 processes were 65, 3. 5 and 27 %. respectively, of the total electron flow. In sediments near the river outlet, sulfate became limiting while nitrate was more abundant. This shifted the relative contributions towards nitrate reduction: 44. 4, 33 and 19%, respectively. At low salinities, depth of the sulfate reduction zone (4 to 10 cm), but not maximum reduction rate, was limited by low sulfate concentrations in the overlying water. The nitrate zone varied from 0.5 to 5 cm depth over the year. Oxygen uptake and sulfate reduction varied seasonally in accordance with temperature. Reduction of nitrate to N, and to NH:, as well as emission of N,O the atmosphere, showed a short maximum in spring and were relatively constant throughout the rest of the year. The spring maximum coincided with a rapid water-temperature increase and a high influx of nitrate from the main river. Annual emission of N 2 0 corresponded to only 1 to 5 % of the measured denitrification. Annual loss of combined nitrogen by denitrification in sediments corresponded to 5 % of nitrate influx from the river.

Mineralization was studied withln the upper 2 m of sediments from the Belt Sea, Kattegat, and Skagerrak at 15 to 200 m water depth. Radiotracer measurements of sulfate reduction rates were related to porewater chemistry (SO,'-, HC03-, P O~~-, NH4+, H2S, and CH,), to solid-phase chemistry (C, S , N, and Fe), and to bacterial distributions. Sulfate penetrated 0.9 to > 3 . 5 m into the sediment. Sulfate reduction rates decreased > 100-fold from m a m a of 6 to 74 nmol cm-3 d-' at the surface to between 0.1 and 1 nmol cm-3 d-' at 1 to 2 m depth. Between 8 and 88 O/O of the total, depth-integrated sulfate reduction took place within the uppermost 0 to 15 cm of the sediment. Maxlma of sulfate reduction or bacterial densibes at the sulfate-methane transition indicated a zone of anaerobic methane oxidation 0.8 to > 2.5 m below the surface. The fraction of the iron pool, which was bound in pyrite, was 17 to 42 %, even in the presence of > 1 mM H2S. Only 4 to 32 % of the H2S produced from sulfate reduction was permanently buried as FeS2 while the rest was reoxidized. Sediment accumulation rates determined from 'I0pb age determinations were 0.3 to 6.2 mm yr-'. The total deposition of organlc carbon, determined from the sum of organic C mineralized by aerobic and anaerobic respiration plus net burial of organic C, was 16.7 to 52.3 mm01 m-' d-'. This was equivalent to about 50 % of the primary productivity in the water column. The net burial rates of organic C were 1.5 to 26 mm01 m-' d-' corresponding to 9 to 50 ' % of the deposited organic C. The bunal of pyritic sulfur corresponded to 9 to 37 O/u of the reducing equivalentes buried as organic C.

Integrated Ocean Drilling Program Expedition 347 aimed to retrieve sediments from different settings of the Baltic Sea, encompassing the last interglacial-glacial cycle to address scientific questions along four main research themes: 1. Climate and sea level dynamics of marine isotope Stage (MIS) 5, including onsets and terminations; 2. Complexities of the latest glacial, MIS 4-MIS 2; 3. Glacial and Holocene (MIS 2-MIS 1) climate forcing; and 4. Deep biosphere in Baltic Sea Basin (BSB) sediments. These objectives were accomplished by drilling in six subbasins: (1) the gateway of the BSB (Anholt), where we focused on sediments from MIS 6-5 and MIS 2-1; (2) a subbasin in the southwestern BSB (Little Belt) that possibly holds a unique MIS 5 record; (3, 4) two subbasins in the south (Bornholm Basin and Hanö Bay) that may hold long complete records from MIS 4-2; (5) a 450 m deep subbasin in the central Baltic (Landsort Deep) that promises to contain a thick and continuous record of the last ~14,000 y; and (6) a subbasin in the very north (Ångermanälven River estuary) that contains a uniquely varved (annually deposited) sediment record of the last 10,000 y. These six areas were expected to contain sediment sequences representative of the last ~140,000 y, with paleoenvironmental information relevant on a semicontinental scale because the Baltic Sea drains an area four times as large as the basin itself. The location of the BSB in the heartland of a recurrently waning and waxing ice sheet, the Scandinavian Ice Sheet, has resulted in a complex development: repeated glaciations of different magnitudes, sensitive responses to sea level and gateway threshold changes, large shifts in sedimentation patterns, and high sedimentation rates. Its position also makes it a unique link between Eurasian and northwest European terrestrial records. Therefore, the sediments of this largest European intracontinental basin form a rare archive of climate evolution over the latest glacial cycle. High sedimentation rates provide an excellent opportunity to reconstruct climatic variability of global importance at a unique resolution from a marine-brackish setting. Comparable sequences cannot be retrieved anywhere in the surrounding onshore regions. Furthermore, and crucially, the large variability (salinity, climate, sedimentation, and oxygenation) that the BSB has under

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This chapter documents the primary operational, curatorial, and analytical procedures and methods employed during the offshore and onshore phases of Integrated Ocean Drilling Program (IODP) Expedition 347. This information concerns only shipboard and Onshore Science Party (OSP) methodologies and data as described in the site chapters. Methods for postexpedition research conducted on Expedition 347 samples and data will be described in individual scientific contributions published after the OSP. Detailed drilling and engineering operations are described in "Operations" within each site chapter and "Operational strategy" in the "Expedition 347 summary" chapter (Andrén et al., 2015). The information in this chapter will enable future identification of data and samples for further scientific investigation by interested parties. Site locationsAll Expedition 347 sites (Fig. F1) were positioned using GPS coordinates supplied by the proponents and based on previous site surveys. As a number of holes were proposed at each site for different uses (e.g., paleoenvironment and microbiology), a central hole position was taken from the proponent-supplied coordinates (Hole A), and then additional positions were calculated radiating out from this position at 20 m intervals, with Holes B and C on either side of Hole A, running along the site survey seismic lines, and Holes D and E perpendicular to this orientation, again on either side of Hole A (Fig. F2). The spacing interval of 20 m between holes was chosen to limit drilling disturbance between holes while maintaining a close enough proximity to correlate between them, enabling the formation of a composite recovery and lithologic splice.Selected positions were relayed to the Hydrographic Surveyor from Geocean, and the Greatship Manisha was settled into position using a dynamic positioning (DP) system. To maintain station accurately within the required tolerance of <1 m for shallowwater sites, the DP system ran for 30-40 min at each location to build a reliable DP model, after which permission was granted to commence operations. Geocean supplied two transponder systems that were used during coring operations as backup for the DP system should there be a failure in the differential GPS (DGPS) signal because of satellite angles, particularly in the river estuary Methods 1

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Following completion of Hole M0067B, the vessel returned to Site M0059 to resample at this location to complement the samples already collected and improve recovery rates in the lower sections. The vessel arrived back at Site M0059 at 0340 h on 29 October 2013 and commenced coring operations.