The Yukon Coast Land Expedition was conducted in July 2022 and 2023 along an active retrogressive thaw slump; active-slump (AS), and a non-slump (NS) transect up to 2000 m from the shore, near Herschel Island-Qikiqtaruk on the Yukon Coast, Northwest Canadian Arctic. The aim was to investigate the effects of terrestrial matter input on community composition and biomass of phytoplankton, bacteria, and microzooplankton, as well as the abundance of mesozooplankton in the nearshore zone. Environmental parameters including water temperature, and salinity, were measured in the water column using handheld deployable CTD while turbidity was measured using Turbidity 2100Q. Water samples were taken from the upper 50 cm using a USB 50050 water sampler for nutrients and carbon concentrations as well as planktonic community analysis.