The topic of ocean acidity is increasingly in the news, and it has recently been blamed for die-offs at B.C. shellfish farms. At the same time this has been going on, Vancouver Aquarium researcher divers have noticed an increase in acidic seaweeds (Desmarestia spp.) in Howe Sound. Coincidence? We don’t know yet.

These seaweeds contain sulphuric acid as a defense mechanism, and if you bit into one, it would taste bitter – like having lemon juice or vinegar on your tongue.

Stringy acid seaweed (Desmarestia viridis)

Stringy acid seaweed (Desmarestia viridis)

Donna Gibbs, Aquarium taxonomist, says they don’t see stringy acid seaweed (Desmarestia viridis) or broad acid weed (Desmarestia ligulata) in Howe Sound very often. “So when I saw it, I was very interested,” she says. Back at the office, she referred to the long term data collected by Pacific Marine Life Surveys and found that these seaweeds were only seen in trace amounts in four years between 1993 and 2002 in this area, and they haven’t been seen since…until now.

The Aquarium researchers can’t say for certain what this means yet. They have to collect and analyze more data before any conclusion can be made. In the meantime, they are continuing with water quality monitoring, which has been conducted in Burrard Inlet and surrounding waters since our opening in the 1950s.

Most recently, the researchers deployed a multiparameter water quality sonde in Howe Sound, which collected data from December 2013 to February of this year. The tubular device (60 cm high and 10 cm in diameter) was anchored to the seafloor while it collected information: depth, temperature, dissolved oxygen, salinity and ph (the unit that measures acidity).

Research coordinator Jessica Schultz at the helm of the Vancouver Aquarium's dive research boat.

Research coordinator Jessica Schultz at the helm of the Vancouver Aquarium’s dive research boat.

Dr. Jeff Marliave, the Aquarium’s vice president of marine science, says that they are paying particularly close attention to Howe Sound in the wake of the sea star wasting syndrome and will continue to conduct research of sea water quality, climate and biodiversity in the area.

Learn about how the Aquarium’s long term ph data contributed to this chapter in Biodiversity Loss in a Changing Planet.

Written by Karen Horak, writer-editor, content and digital experience at the Vancouver Aquarium.

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