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Research was conducted to infections of a (PB1-) potato crop grown from minitubers with blackleg causing soft rot Pectobacteriaceae (BL-SRP). For this, an enrichment multiplex TaqMan assay (EM-TaqMan assay) was developed, allowing to detect the various BL-SRP variants simultaneously with a sensitivity of 10-100 cells per gram plant material. During four growing seasons (2019- 2022) PB1 crops were surveyed. Plant tissues (leaves, stems and tubers) were collected and analyzed using the EM-TaqMan assay. During wet growing seasons relatively high infection incidences were found both in leaves (8%) and tubers (≤ 42%), in particular with a virulent haplotype of P. brasiliense. During dry seasons, only low incidences were found. It was found that P. brasiliense is able to enter a VBNC-state in the presence of cupper ions (CuSO4). However, we were unable to find conditions to let the cells multiply again. Therefore we have no indications that VBNC play a role in the epidemiology of P. brasiliense. The role of potential infection sources was studied. BL-SRP were not found in rain water, but 2.3% of the sampled insects at a PB crop were contaminated with BL-SRP, indicating that insects may be important in the transmission of BL-SRP from an infection source to a PB1 crop. Inoculum deposited on haulms poses a high risk for tuber infections. This was studied by spray inoculation of haulms of young potato plants with different densities (102 – 109 cfu per plant) of a virulent, rifampicin resistant mutant of P. brasiliense. In a wet growing season, low densities could already result in haulm infections while all plants yielded infected tubers. In a dry year only at the highest inoculum densities haulm infections were found, but tuber infections even at the lowest densities. Analysis conducted at the NAK to the role of environmental factors on the infection level of seed potatoes were done using data of seed lots tested in high classes in the period 2015-2018. Characteristics point

Groundwater discharge into the sea occurs along many coastlines around the world in different geological settings and constitutes an important component of global water and matter budget. Estimates of how much water flows into the sea worldwide vary widely and are largely based on onshore studies and hydrological or hydrogeological modeling. In this study, we propose an approach to quantify a deep submarine groundwater outflow from the seafloor by using autonomously measured ocean surface data, i.e., 222Rn as groundwater tracer, in combination with numerical modeling of plume transport. The model and field data suggest that groundwater outflows from a water depth of ∼100 m can reach the sea surface implying that several cubic meters per second of freshwater are discharged into the sea. We postulate an extreme rainfall event 6 months earlier as the likely trigger for the groundwater discharge. This study shows that measurements at the sea surface, which are much easier to conduct than discharge measurements at the seafloor, can be used not only to localize submarine groundwater discharges but, in combination with plume modeling, also to estimate the magnitude of the release flow rate.

Carbon capture and storage is a key mitigation strategy proposed for keeping the global temperature rise below 1.5 °C. Offshore storage can provide up to 13% of the global CO2 reduction required to achieve the Intergovernmental Panel on Climate Change goals. The public must be assured that potential leakages from storage reservoirs can be detected and that therefore the CO2 is safely contained. We conducted a controlled release of 675 kg CO2 within sediments at 120 m water depth, to simulate a leak and test novel detection, quantification and attribution approaches. We show that even at a very low release rate (6 kg day−1), CO2 can be detected within sediments and in the water column. Alongside detection we show the fluxes of both dissolved and gaseous CO2 can be quantified. The CO2 source was verified using natural and added tracers. The experiment demonstrates that existing technologies and techniques can detect, attribute and quantify any escape of CO2 from sub-seabed reservoirs as required for public assurance, regulatory oversight and emissions trading schemes.