Biogeochemical Regionalization, Variability and Trends of British Columbia’s Coastal Ocean

The coastal ocean of British Columbia (BC) is a highly complex environment influenced by diverse processes such as upwelling and downwelling, intense tidal mixing, and large volumes of freshwater/terrigenous input from the Pacific Coastal Temperate Rainforest. This region of the Northeast Pacific is further subject to the effects of large amplitude climate oscillations (e.g., PDO, ENSO), and is increasingly impacted by marine heatwaves. This study aims to examine the biogeochemical regionalization, and spatiotemporal variability and trends of BC’s coastal ocean water properties through the analysis of a combination of historical and recent data. Physical and biogeochemical observations collected over the past nine decades by local and international organizations (e.g., Fisheries and Oceans Canada, Hakai Institute, National Oceanographic and Atmospheric Administration) are compiled, including temperature and salinity values, and dissolved oxygen, nutrient and chlorophyll concentrations. Data are then utilized to define and characterize regions of BC’s coastal waters based on regional differences in biogeochemical ocean properties, considering short-term variability and long-term trends. This description of the regionalization of BC’s coastal waters will serve to improve spatial management of the province’s fisheries, water quality and Marine Protected Areas. Biogeochemical indicators are necessary for adequately predicting the consequences of climate anomalies that have cascading effects on the food web, and this work establishes such indicators via a regionalization approach.