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Environmental DNA (eDNA) preserved in marine sediments is increasingly being used to study past ecosystems. However, little is known about how accurately marine biodiversity is recorded in sediment eDNA archives, especially planktonic taxa. Here, we address this question by comparing eukaryotic diversity in 273 eDNA samples from three water depths and the surface sediments of 24 stations in the Nordic Seas. Analysis of 18S‐V9 metabarcoding data reveals distinct eukaryotic assemblages between water and sediment eDNA. Only 40% of Amplicon Sequence Variants (ASVs) detected in water were also found in sediment eDNA. Remarkably, the ASVs shared between water and sediment accounted for 80% of total sequence reads suggesting that a large amount of plankton DNA is transported to the seafloor, predominantly from abundant phytoplankton taxa. However, not all plankton taxa were equally archived on the seafloor. The plankton DNA deposited in the sediments was dominated by diatoms and showed an underrepresentation of certain nano‐ and picoplankton taxa (Picozoa or Prymnesiophyceae). Our study offers the first insights into the patterns of plankton diversity recorded in sediment in relation to seasonality and spatial variability of environmental conditions in the Nordic Seas. Our results suggest that the genetic composition and structure of the plankton community vary considerably throughout the water column and differ from what accumulates in the sediment. Hence, the interpretation of sedimentary eDNA archives should take into account potential taxonomic and abundance biases when reconstructing past changes in marine biodiversity. [ABSTRACT FROM AUTHOR]

Background: Imaging of cell death can provide an early indication of treatment response in cancer. [99mTc]Tc-Duramycin is a small-peptide SPECT tracer that recognizes both apoptotic and necrotic cells by binding to phosphatidylethanolamine present in the cell membrane. Preclinically, this tracer has shown to have favorable pharmacokinetics and selective tumor accumulation early after the onset of anticancer therapy. In this first-in-human study, we report the safety, biodistribution and internal radiation dosimetry of [99mTc]Tc-Duramycin in healthy human volunteers. Results: Six healthy volunteers (3 males, 3 females) were injected intravenously with [99mTc]Tc-Duramycin (dose: 6 MBq/kg; 473 ± 36 MBq). [99mTc]Tc-Duramycin was well tolerated in all subjects, with no serious adverse events reported. Following injection, a 30-min dynamic planar imaging of the abdomen was performed, and whole-body (WB) planar scans were acquired at 1, 2, 3, 6 and 23 h post-injection (PI), with SPECT acquisitions after each WB scan and one low-dose CT after the first SPECT. In vivo 99mTc activities were determined from semi-quantitative analysis of the images, and time-activity curves were generated. Residence times were calculated from the dynamic and WB planar scans. The mean effective dose was 7.61 ± 0.75 µSv/MBq, with the kidneys receiving the highest absorbed dose (planar analysis: 43.82 ± 4.07 µGy/MBq, SPECT analysis: 19.72 ± 3.42 μGy/MBq), followed by liver and spleen. The median effective dose was 3.61 mSv (range, 2.85–4.14). The tracer cleared slowly from the blood (effective half-life of 2.0 ± 0.4 h) due to high plasma protein binding with < 5% free tracer 3 h PI. Excretion was almost exclusively renal. Conclusion: [99mTc]Tc-Duramycin demonstrated acceptable dosimetry (< 5 mSv) and a favorable safety profile. Due to slow blood clearance, optimal target-to-background ratios are expected 5 h PI. These data support the further assessment of [99mTc]Tc-Duramycin for clinical treatment response evaluation. Trial registration: NCT05177640, Registered April 30, 2021, https://clinicaltrials.gov/study/NCT05177640. [ABSTRACT FROM AUTHOR]

The mid-Pliocene (3.3-3.0 Ma) is the most recent period in Earth’s history of sustained, global warmth analogous to predicted near-future climates. Despite considerable efforts to characterize and understand the climate dynamics of the mid-Pliocene, the deep ocean and its response to this warming remains poorly understood. Here we present new mid-Pliocene Mg/Ca and Δ47 (“clumped isotope”) temperatures from the deep Pacific and North Atlantic oceans. These records cover the transition from Marine Isotope Stage (MIS) M2 — considered the most pronounced “glacial” stage of the mid-Pliocene — to the warm KM5 interglacial. We find that a large (>4°C) temperature gradient existed between these two basins throughout that interval, with the deep North Atlantic considerably warmer and likely saltier than at present. We interpret our results to indicate that the deep Pacific and North Atlantic oceans were bathed by water masses with very different physical properties during the mid-Pliocene, and that only limited deep oceanic exchange occurred between the two basins. Our results point to a fundamentally different mode of ocean circulation or mixing compared to the present, where heat and salt is distributed from the North Atlantic into the Pacific. The amplitude of cooling observed at both sites during MIS M2 suggests that changes in benthic δ 18O associated with this cold stage were mostly driven by temperature change in the deep ocean rather than ice volume. [ABSTRACT FROM AUTHOR]

A palynological analysis with marine palynomorphs (dinoflagellate cysts, acritarchs, green algae) and terrestrial palynomorphs (pollen and spores) of the Kasterlee and Poederlee formations provides new insights in the depositional history at the southern border of the North Sea basin (northern Belgium) around the Miocene-Pliocene transition. Dinoflagellate cyst stratigraphy constrains the age of the Kasterlee Formation in the Oud-Turnhout borehole between 7.5 and 5.32 Ma. The upper boundary of the formation can be correlated with sequence boundary Me2 at 5.73 Ma of Hardenbol and co-workers, which further constrains its age to the time interval 7.5 5.73 Ma. The palynomorph assemblages reflect a near-coast depositional environment. Where present, the Kasterlee Formation thus terminates the Miocene series in northern Belgium. The overall shallow nature of the latest Miocene deposits is related to a sea-level lowering caused by the onset of globally cooling conditions. For the first time, palynology is applied to estimate the age of the Poederlee Formation, suggesting it was deposited during the Mid-Pliocene warm period. Dinoflagellate cysts and sequence stratigraphy together constrain the age of the unit between 3.21 and 2.76 Ma, and possibly even between 3.21 and 3.15 Ma. The Poederlee Formation was deposited in neritic environments, which shoaled in the upper part of the unit as a consequence of the decreasing availability of accommodation space. We demonstrate that the magnitude of the hiatus between the Miocene and Pliocene series varies strongly at the southern boundary of the North Sea Basin, and lasts in the Antwerp area c. 3.2 million years and c. 2.52 million years in the Campine area. Keywords: dinoflagellate cysts, palynology, Miocene, Pliocene, North Sea Basin. doi:10.1017/S0016756810000191

Dinoflagellate cysts and sequence stratigraphy are used to date accurately the Tunnel-Canal Dock section, which contains the most complete record of marine Pliocene deposits in the Antwerp harbour area. The Zanclean Kattendijk Formation was deposited between 5.0 and 4.4 Ma during warm-temperate conditions on a shelf influenced by open-marine waters. The overlying Lillo Formation is divided into four members. The lowest is the Luchtbal Sands Member, estimated to have been deposited between 3.71 and 3.21 Ma, under cooler conditions but with an open-water influence. The Oorderen Sands, Kruisschans Sands and Merksem Sands members of the Lillo Formation are considered a single depositional sequence, and biostratigraphically dated between 3.71 and c. 2.6 Ma, with the Oorderen Sands Member no younger than 2.72-2.74 Ma. Warm-temperate conditions had returned, but a cooling event is noted within the Oorderen Sands Member. Shoaling of the depositional environment is also evidenced, with the transgressive Oorderen Sands Member passing upwards into (near-)coastal highstand deposits of the Kruisschans Sands and Merksem Sands members, as accommodation space decreased. Applying sequence stratigraphy to our section implies that the Kattendijk/Lillo Formation boundary corresponds to the sequence boundary (SB) Za2 (4.04 Ma), the Luchtbal/Oorderen sands boundary to SB Pia1 (3.21 Ma), and the top of the Merksem Sands to SB Pia2 (2.76 Ma). Finally, the Belgian deposits are compared with marine Pliocene deposits of eastern England. Keywords: dinoflagellate cyst, palynology, Pliocene, North Sea, sequence stratigraphy.

Analyses of observational data (from year 1870 AD) show that Sea Surface Temperature (SST) anomalies along the pathway of Atlantic Water transport in the North Atlantic, the Norwegian Sea and the Iceland Sea are in-phase at multidecadal time scales. In-phase SST anomaly relationships are also observed over hundreds of thousands of years during parts of the Pliocene (5.23–5.03, 4.63–4.43 and 4.33–4.03 Ma). However, when investigating CMIP6 SSP126 future scenario runs (next century) and Pliocene reconstructions (5.23–3.13 Ma), three additional phase relations emerge: 1) The Norwegian Sea is out of phase with the North Atlantic and the Iceland Sea (Pliocene; 4.93-4.73 and 3.93–3.63 Ma); 2) The Iceland Sea is out of phase with the North Atlantic and the Norwegian Sea (Pliocene; 3.43–3.23 Ma); 3) The North Atlantic is out of phase with the Norwegian and Iceland Seas (future trend). Hence, out of phase relationships seem to be possible in equilibrium climates (Pliocene) as well as in response to transient forcing (CMIP6 SSP 126 low-emission future scenario). Since buoyancy is a key forcing for inflow of Atlantic Water to the Norwegian Sea, we investigate the impacts of buoyancy forcing on the phase relation between SST anomalies in the North Atlantic, Norwegian and Iceland Seas. This is done by performing a range of idealized experiments using the Massachusetts Institute of Technology general circulation model (MITgcm). Through these idealized experiments we can reproduce three out of four of the documented phase relations: in-phase relationships under weak to intermediate fresh water forcing over the Nordic Seas; the Iceland Sea out of phase with the North Atlantic and the Norwegian Sea under weak atmospheric warming over the Nordic Seas; and the North Atlantic out of phase with the Norwegian and Iceland Seas under strong atmospheric warming over the Nordic Seas. We suggest that the unexplained phase relation, when the Norwegian Sea SSTs are out of phase with the North Atlantic and the Iceland Sea, may reflect a response to a weakened Norwegian Atlantic Current compensated by a strong Irminger current, or an expanded East Greenland Current. [ABSTRACT FROM AUTHOR]