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The climate is rapidly changing in the Arctic, where global warming is reported to be about up to four times the global average in the last two decades. Aligned with this Arctic Amplification, other climate-related phenomena are also changing, or are bound to change, on a regional scale. For instance, the accelerated glaciers’ melting is forcing a transition of some glaciers from marine- to land-terminating systems and, therefore, impacting the balance of freshwater input into the oceans. As consequence, other ocean climate-related processes (e.g., water masses (trans)formation, baroclinicity of geostrophic currents) are expected to be impacted.Within this context, and as part of the “Innovative study on regional high-resolution imaging of glacier induced plankton dynamics in West-Greenland fjords (IOPD)” project, we visited the fjord system in the Uummannaq area, off Western Greenland, aboard the R/V Sanna, from 28/Jun to 10/Jul/2022. In this region, fjords are marked by both land- and marine-terminating glaciers. During the cruise, we performed 47 hydrographic stations of the entire water column into 5 different fjords - from their mouth to the innermost accessible location. These stations are complemented by an offshore transect from the fjord mouth to the shelf edge.Based on the in-situ measurements described above, complemented by other historical oceanographic measurements and state-of-the-art datasets for solid and liquid freshwater input provided by the Geological Survey of Denmark and Greenland (GEUS), we aim at characterizing the fjord system in the Uummannaq area in perspective of the ongoing climate changes. More specifically, this work addresses the following questions (i) What is the long-term and recent freshwater input to the region? And, is this input undergoing changes in the latest years? (ii) How are the water masses quantitatively distributed within the fjords and adjacent continental shelf? Are there differences between fjords? And, how do the connections with the adjacent continental shelf take place? (iii) Are there differences between marine- and land-terminating systems in terms of (solid and liquid) freshwater input and water mass distribution in the region? If so, what are these differences?

Optical imaging devices such as the Video Plankton Recorder (VPR) harness unique capabilities to perform in situ observations and observe planktonic organisms in their natural environmental context. However, applying this technology in shallow and turbid coastal waters comes with a number of challenges. Depending on the research goal, methodological choices need to be made regarding the appropriate towing procedure and instrument settings, like magnification or field of view. In addition, limitations can be expected related to the physical characteristics of the water column, more specifically regarding suspended matter concentration and turbidity. To inform VPR users on the possibilities and limitations of the device in shallow and turbid coastal waters, this paper evaluates a number of specific deployment procedures in the Belgian part of the North Sea (BPNS). For three different towing procedures the practical feasibility, characteristics and output are assessed and the assets and liabilities for each of the tow types are discussed. A Z-shaped and a clover-shaped tow type are seen as best fit for detailed characterization of the plankton community of a limited geographical area. A straight tow type is more suitable for plankton studies over a larger area, with the potential to capture local plankton abundance peaks and to determine the relation with the spatial variation of the environmental conditions. The capacity of the various VPR magnification settings to capture specific plankton taxa or size groups, was tested during four straight line transects with different magnifications. The highest magnification can be used for organisms from 0.3 to 0.7 mm while the low magnification allows to observe larger organisms within the size range of 1.0 to 3.8 mm. Finally, the boundary conditions for the deployment of the VPR related to the turbidity of the water column were defined and the implications for deployment within the study area were investigated. This study shows that high turbidity values over 6.2 NTU inhibit the collection of useable data, complicating the VPR's application in many coastal and transitional waters.