A Review of Apparent 20th Century Changes in the Presence of Mussels (Mytilus trossulus) and Macroalgae in Arctic Alaska, and of Historical and Paleontological Evidence Used to Relate Mollusc Distributions to Climate Change

• Published in: Arctic 2003-12, Vol.56 (4), p.391-407
• Main Authors: Feder, Howard M., Norton, David W., Geller, Jonathan B.
• Format: Article
• Language: English
• Subjects: Algae; Barrier islands; Beaches; Benthic communities; Benthos; Climate change; Climatic changes; Coasts; Deltas; Desiccation; Environmental aspects; Estuaries; Glaciers; Glaciohydrology; Inlets; Intertidal zone; Invertebrate populations; Lagoons; Macroalgae; Marine; Marine algae; Marine biology; Marine ecology; Marine mammals; Measurement; Mollusks; Mussels; Natural history; Predation; Predators; Salinity; Scour; Sea ice; Seas; Shellfish; Spawning; Storms; Streams; Taxonomy; Tides; Water depth; Water temperature
• ISSN: 0004-0843; 1923-1245
• DOI: 10.14430/arctic636

Live mussels attached to fresh laminarioid brown algae, all fastened to clusters of pebbles and small cobbles, were repeatedly cast ashore by autumn storms at Barrow, Alaska, in the 1990s. Specimens of Laminaria saccharina and L. solidungula shorten by 100 km a 500 km gap (Peard Bay to Stefansson Sound) between previously known concentrations of these kelp species. For the genus Mytilus, a 1600 km gap in fully documented locations existed between Kivalina in the southern Chukchi Sea and the Mackenzie River delta. Barrow specimens were identified using a mitochondrial DNA marker as M. trossulus, an identity consistent with dispersal from the Pacific-Bering side of the Arctic. Live mussels and macroalgae were neither washed up by storms nor collected by active biological sampling during extensive benthic surveys at Barrow in 1948-50. We cannot interpret the current presence of these bivalves and macrophytes as Arctic range extensions due to warming, similar to those manifested by the tree line in terrestrial systems and by Pacific salmon in marine environments. Supplemental information and critical evaluation of survey strategies and rationales indicate that changes in sea temperatures are an unlikely cause. Alternative explanations focus on past seafloor disturbances, dispersal from marine or estuarine refugia, and effects of predators on colonists. This review suggests refining some interpretations of environmental change that are based on the extensive resource of Cenozoic fossils of Arctic molluscs. /// Durant les années 1990, des moules vivantes fixées sur des algues brunes laminaires, toutes attachées à des agrégats de galets et de petits cailloux, ont été rejetées par les tempêtes automnales sur les rivages de Barrow, Alaska. Des spécimens de Laminaria saccharina et de L. solidungula raccourcissent de 100 km la distance de 500 km (de Peard Bay à Stefansson Sound) qui sépare les concentrations précédemment connues de ces espèces de varech. Pour le genre Mytilus, il existait une distance de 1600 km séparant les emplacements très bien documentés allant de Kivalina dans la partie méridionale de la mer des Tchouktches au delta du Mackenzie. À l'aide d'un marqueur ADN mitochondrial, les spécimens de Barrow ont été identifiés comme appartenant à M. trossulus, ce qui s'accorde bien avec une dispersion depuis le côté Pacifique-Bering de l'Arctique. Lors d'un vaste progamme de relevés benthiques à Barrow dans les années 1948-1950, les moules vivantes et les mac