Using macroalgae as an indicator of ocean conditions through time.

Researchers in Japan recently published a study in the Journal of Oceanography on using position-dependent radiocarbon as an indicator of oceanographic conditions during algal growth.

The macroalga Undaria pinnatifida grows in a predictable way, older growth at the top and the new growth is at the bottom (image below)

The researchers hypothesized that the age of the Undaria tissue would correlate with ocean conditions through time. Inorganic carbon ∆14C was tracked in tissues and ambient water through time. The study concluded that inorganic carbon in the Undaria tissues did correlate with oceanic samples through time.

They concluded that this technique “provides a new tool to better understand the role of oceanographic conditions in sustaining coastal ecosystem productivity.”

It will be interesting to see this new approach applied to other species, such as Pterygophora californica, which can live upwards of 15 years.

Seaweed common names: Wakame

There are many names for commonly consumed seaweeds. However, the species they refer to vary by region and culture. We will cover some of the most commonly used names for seaweeds, and review the differences between connotation and denotation. This series will review some of the most common common-names in use.

Previous posts include: Nori

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Wakame

Wakame is another edible seaweed popularized by the Japanese. You are probably familiar with wakame in the form of seaweed salad or as the little green strips within your miso soup.

ワカメ pronounced wakame, translates to seaweed, but in modern Japanese dictionaries directly refers to a specific species, Undaria pinnatifida.

Undaria pinnatifida is a brown seaweed (kelp) that grows substantially along rocky temperate coasts. The Latin root is Unda = wavy, and Pinna = pinnately cleft. Wakame in Japanese is derived from waka + me (若布, lit. young seaweed).

As early as the 8th century wakame was known to be harvested off the coast of Japan, China, and Korea. Undaria pinnatifida has since then spread to various regions of the world and has been added to the list of 100 most invasive species. Most recently Undaria pinnatifida crossed the pacific ocean again on debris carried from the 2011 tsunami.

Wakame is typically harvested, dried or blanched, and then sold. Upon purchase the wakame is then re-hydrated by soaking in water or soups.

While in the USA we are more familiar with the term wakame, other cultures call Undaria pinnatifida by other names: Qun dai cai (Chinese), Miyeouk (Korean), or sea mustard (English).

Today many foragers refer to other species as wakame. On the north coast some species of Alaria are being labeled as wakame as there is no native Undaria.