Mass Bleaching in Intertidal Canopy-Forming Seaweeds after Unusually Low Winter Air Temperatures in Atlantic Canada

• Published in: Diversity (Basel) Vol. 15; no. 6; p. 750
• Main Authors: Scrosati, Ricardo A, Cameron, Nicole M
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01-06-2023
• Subjects: Air temperature; Algae; Biodiversity; Biogeography; Biological diversity; Biological diversity conservation; Bleaching; Canopies; Climate change; Climatic changes; Coastal ecosystems; Coasts; Cold; cold spell; Conflicts of interest; Environmental aspects; Extreme weather; Global temperature changes; Heat; Heat waves; intertidal; Invertebrates; Marine algae; seaweed; Seaweeds; Summer; Temperature; Thalli; Tide pool ecology; Wineries & vineyards; Canada; Nova Scotia; United States > US; North America; Arctic region; Nova Scotia Canada
• ISSN: 1424-2818; 1424-2818
• DOI: 10.3390/d15060750

Contemporary climate change is increasing the occurrence of extreme weather events, heat waves being common examples. Here, we present visual evidence of mass bleaching in intertidal seaweeds following an unusually severe cold snap in Atlantic Canada. In February 2023, the air temperature on the Nova Scotia coast dropped below −20 °C for the first time in at least ten years. Such extreme temperatures lasted for several hours at low tide and were followed by extensive bleaching in whole thalli of the canopy-forming algae Chondrus crispus and Corallina officinalis. The loss of these foundation species might negatively impact intertidal biodiversity.