This dataset is one of three datasets presenting marine biogeochemistry data from four sites in Clayoquot Sound, Vancouver Island, British Columbia from water, sediment, and porewater samples that were collected aboard the R/V Rachel Carson in October 2023. These sites were selected because they represent hotspots of organic carbon burial spanning a range of geochemical conditions. They represent a range of oxic to historically anoxic water columns, and receive organic matter inputs varying from predominantly terrestrial to predominantly marine sources. Together, these datasets provide a framework to evaluate the controls and drivers of organic matter preservation in fjord sediments. See the "Related Datasets" section for the other datasets.