Red Seaweeds

Do environmental properties associated with changing land-ocean connections affect the quality and quantity of harvested red seaweeds used for personal consumption and trade?

 

Traditional seaweed harvesters in Klukwan and Haines have observed changes in red seaweed harvest abundance.  want to know the best time to harvest seaweed, from where, and how their harvest could be affected as the glacial landscape shifts. 

As glaciers melt, the force they exert on the continental crust surrounding the Gulf of 猫咪社区官网 lessens. Because of this phenomenon, called isostatic rebound, scientists hypothesize that the rocky intertidal sits higher from the sea surface than in the past. Therefore, the red seaweeds in these habitats are unsubmerged by the tide for longer periods of time, exposing them to air and herbivores. 

The Interface of Change red seaweeds research team therefore hypothesizes that this increased exposure could affect the healthy growth of this important food source.

 

Hypotheses:
1.) Changing freshwater discharge patterns will increase turbidity, lower temperature, reduce salinity, and modify sources of nutrients from surface and groundwater inputs to the coast, which will decrease biomass and nutritional quality of Devaleraea mollis and Palmaria hecatensis.
2.) Target red seaweeds will show reduced photosynthetic activity and growth rates, and increased stress responses when exposed to turbid and colder water typical of glacial estuaries.
3.) Increased exposure to air and freshwater driven by longer periods of emersion will facilitate increased consumption rates by local herbivores, contributing to a significant reduction of harvestable red seaweeds (Devaleraea mollis and Palmaria hecatensis).

 

To study changes in red seaweed growth, a team of UAF researchers and community members collect samples of these red seaweed species as well as sea water sample twice per month during their growing season from March to June.

Two women wearing warm hats and brightly colored rain jackets are crouched in the intertidal with rocks covered in red seaweeds. They have a weather proof notebook, Ziploc samples bags, and a cooler.
Photo courtesy of Lindsay Meyer
UAF graduate student Lindsay Meyer and Chilkoot Indian Association environmental scientist Meredith Pochardt collect red seaweeds samples.

The team includes professor Schery Umanzor, graduate student Lindsay Meyer, 猫咪社区官网 EPSCoR advisor and Klukwan schoolteacher Justina Starzynski-Hotch, and Chilkoot Indian Association environmental team members Liam Cassidy and Meredith Pochardt. The seaweed samples are then processed, and their chemistry is compared with that of the sea water to determine the environmental effects on seaweed growth, nutritional quality, and photosynthesis.

Mariculture lab technician Maribel Montiel, Klukwan residents Justina Starzynski-Hotch and Don Hotch, and Liam Cassidy of the Chilkat Indian Association assist with spring sampling.

Photo courtesy of Lindsay Meyer.
Mariculture lab technician Maribel Montiel, Klukwan residents Justina Starzynski-Hotch and Don Hotch, and Liam Cassidy of the Chilkat Indian Association assist with spring sampling.

A vial of a frond of red seaweed sitting on a rock.
Photo courtesy of Schery Umanzor.
A sample vial of a young frond of red seaweed.
Red seaweeds respond quickly to physical and chemical changes in their environments, such as changes in the length of time they are exposed to the air. These changes can be tracked through assays on seaweed tissue.

 

At the , professor Patrick Tomco and postdoctoral research Monica Brandhuber lead fellow researchers on processing the seaweed tissue and seawater samples and performing lab analyses to correlate seaweed metabolites with nutrient levels in the seawater. 

 

Red Seaweeds Team