The effects of ocean acidification and warming on the metabolic physiology of juvenile northern spot shrimp (Pandalus platyceros)

Abstract

Northern spot shrimp (Pandalus platyceros) support important commercial, subsistence, sport, and personal use fisheries in Alaska. This species is currently experiencing population declines in Southeast Alaska, mandating fishery closures in previously productive regions. Northern spot shrimp are harvested as adults and declining populations may be a result of limited recruitment into the fishery. Very little is known about the physiology of P. platyceros early life history stages and no known data exists on how early life history stages may be affected by environmental stressors such as ocean acidification (OA) and ocean warming (OW). OA is a result of increased anthropogenic carbon dioxide (CO₂) input into the ocean. Increased pCO₂ affects both the physical and chemical properties of the ocean, which, in turn, affects the marine biota. In addition to OA, ocean warming (OW) is another environmental stressor associated with ocean change. The Intergovernmental Panel on Climate Change (IPCC) predicts an oceanic pH decrease of 0.2-0.4 units and an increase in ocean temperatures up to 5°C by the year 2100. The goal of this thesis is to characterize potential individual and interactive effects of increased pCO₂ and increased temperature on the metabolic rate (MO₂), gene expression of heat shock protein 70 (Hsp70), and gene expression of carbonic anhydrase (CA) in juvenile P. platyceros. In order to assess the individual and interactive effects of these environmental stressors on juvenile P. platyceros physiology, I built a low-cost open hardware OA and OW system in the seawater lab at the University of Alaska Southeast. This pH-stat system, based on open-source Arduino platform, allowed manipulation of pH and temperature in line with the IPCC's future predicted ocean conditions. Juvenile P. platyceros are a model organism for this type of research due to predictions that early developmental stages, the requirement of calcification for growth, and cold-water marine organisms may be most susceptible to OA and OW stressors. Understanding how this ecologically and economically important species may be affected by environmental stressors can highlight the capacity of P. platyceros to withstand ocean change.