Algal Biology, Ecology, and Biogeography

The small, mid-ribbed kelp Alaria esculenta dominates in wave-beaten, shallow zones or rocky Labrador shores.

Although Walter Adey's specialty is coralline algae (calcified, lichen-like red algae that grow from the tropics to arctic marine waters), he has carried out extensive field work from Arctic to tropical North Atlantic and Caribbean on a wide range of seaweeds. He has concentrated his research on ecological studies using quantitative analyses of biomass and area cover.

Subarctic Coralline Algae and the Thermogeographic Model

Diagramatic representation of the Thermogeographic Model developed by Dr. Adey and Dr. Robert Steneck of the University of Maine. The Model shows how concentrations of coastal area at different temperatures over the last 3 million years has produced aggregations of rich biota (biogeographic regions). The blue contours show the abundance of Subarctic coralline algal species relative to the Model.

Cellular growth patterns in several genera and species of Subarctic coralline algae. The three genera shown have very different patterns for forming and growing new cells. Also, species of the same genus (Lithothamnion-shaded ellipses) show different cell sizes as minor variations on the common generic pattern.

Sorting seaweeds from a harvest quadrat aboard the R/V Alca i. Each species is separated, weighed and logged to develop coastal and depth distribution patterns.

Figure-D.-Preparing-for-dive-in-Nova-Scotia.jpg

Preparing to dive in Labrador to harvest seaweeds from meter-square quadrats of rocky bottom. The species biomass data from hundreds of quadrats from Labrador to Cape Cod are being used to further test the Thermogeographic Model, the validity of which was previously demonstrated by percent cover of coralline algae on rocky bottoms.

Bray-Curtis multivariate similarity ordination plot. This graphic strongly separates NLQ (Subarctic) stations from the Gulf of Maine (GOM) and Southern Nova Scotia (SNS) stations in the transitional (Subarctic/Boreal) zone. The deepest depth zones at exposed stations in GOM and SNS crossover into the range of the Subarctic; this results from the dominance of Subarctic species related to a strong thermocline, and colder temperatures at depth.