Summary of Research Activities:The planned sampling operations for 2025 are similar to those carried out in the Canadian Arctic by the CCGS Amundsen since 2004. These operations are part of the ongoing effort of ArcticNet to understand the ecosystem response to climate variability and change. In the Arctic Ocean, sea-ice dynamics and hydrography will ultimately determine primary production, microbial activity, zooplankton and larval fish dynamics and benthos productivity. The objectives are 1) to quantify and map the Spring, Summer and early Fall distribution and contamination levels of the main components of the pelagic and benthic food webs in the study area and 2) to quantify the response of the pelagic and benthic communities to physical forcing processes. These processes affect the movement of carbon to the ocean floor and the transfer of energy (and contaminants) up the food web to higher trophic levels such as marine mammals, birds, polar bears and ultimately humans. Sampling of the pelagic and benthic environments will be conducted at stations identified in the study area (see 2025 Amundsen Expedition Plan). A CTD/Rosette sampler will be deployed to measure the physico-chemical parameters of the water column. Various size plankton nets will be deployed for the determination of zooplankton and larval fish abundances and contaminant levels. To complement the plankton net tows and determine the vertical position and migration of plankton and fish in the water column, a scientific echosounder (EK80) will be operated during transit between stations. To validate echoes obtained from the sounder, pelagic juvenile and adult fish will be sampled using an Isaacs-Kidd Midwater Trawl (IKMT) and benthic beam trawl. To gain year-long understanding of the oceanography of the Arctic seas, moorings will be deployed from the Amundsen at specific locations. In some instances, moorings already in the water will also be recovered. A box corer, multi-corer, Agassiz trawl and other benthic samplers will be used to assess the abundance, diversity and distribution of benthic organisms and levels of contaminants and carbon in the sediments. For geotechnical analyses, a piston corer or gravity corer will also be deployed to recover the upper 9 metres of sediment (surface of 0.01 m2). The Ship is also equipped with a multibeam and sub-bottom profiler to conduct multibeam and sub-bottom surveys. The Surveys will be conducted in between stations along the sampling transects in open water. Land based operations are also planned during the 2025 Amundsen expedition. These activities greatly depend on weather conditions. Access to the land with the ship's helicopter is an efficient way to reach locations along the cruise track and supports research projects related to water quality, geology and glaciology. River and rock sampling: The sampling sites will be accessed using the ship’s helicopter. Water sampling in the rivers and rock collection from large boulders will take approximately one hour per site. One scientist will collect water samples with a syringe (total volume: max 5L), sediment sample with a spatula and small rocks fragments. The total amount of sediment collected from each river and boulder site will fits in one large Ziploc bag (about 2L). All samples will be brought back on the ship, refrigerated or frozen, and analysed in laboratories after the expedition. Many potential sites are identified, but we do not expect to sample more than 10 rivers. Rocks sampling will help scientists understand the geological history of Melville Island. Ice sampling and surveys: The ship’s helicopter will be used to conduct aerial surveys of the outlet glaciers and adjacent ice cap regions to understand glacier thickness and movement. On-ice operations on the glaciers could include ice and meltpond sampling. Furthermore, the recovery of a GPS station currently in operation on Ellesmere Island is planned, if the weather is suitable. Overall, the land-based sampling aims to collect Canadian Arctic river water samples for chemical analysis, including measurement of greenhouse gases (methane and nitrous oxide) and to recover riverbank sediments and rock fragments deposited near the mouth of the rivers. The geological analyses of the mineralogical, geochemical and magnetic properties of these river samples will provide information on each river’s bed load and grain size and will be used to identify the detrital sources of the sediments. To place the current melting of Arctic ice caps and glaciers in perspective, it is necessary to understand their past geological history. To do so, this project will study glacier ice, meltponds, shallow waters and beach sediments at the outlets of the main glaciers of Baffin Island, western Devon Island and Ellesmere Island to understand their past and present histories through mineral, magnetic, chemical and biological signatures.