Dr. Bjartmar Sveinbjörnsson
My research is directed at answering questions regarding the functions of plants and their ecosystems.
I have worked on the topic of forest limit and treeline, both their northernmost latitude and their uppermost altitude. I have worked at treelines in Sweden, Iceland, Italy, Canada, and Alaska. I have had a large number of students, both graduate and undergraduate and two post-docs working with me at these sites. Presently I have one Ph.D. student Tumi Traustason working on a project that spans boreal Alaska.
Here I am studying a white spruce tree damage at treeline. The forest stand below represents the northernmost contiguous forest along the Dalton Highway in the Brooks Range, Alaska.
Allison Chang, an REU student is looking at a mat-formed white spruce in the Chugach Mountains, south-central Alaska.
In my treeline research, I have collaborated with a number of researchers such as Staffan Karlsson at Uppsala University and others in Sweden, Roger Ruess at University of Alaska Fairbanks. Presently I collaborate with Dr. Paddy Sullivan at University of Alaska Anchorage on a project in the Noatak drainage in northwestern Alaska.
Here, Paddy Sullivan and I are setting up ITEX chambers and microclimate monitoring equipment near the top of the Dome in the western flank of the Chugach Mountains near Anchorage.
We are studying the reasons for reduced abundance of lichens and bryophytes under simulated global change conditions.
In Iceland, where I grew up and obtained my undergraduate degree, volcanoes and lava fields are an important aspect of the landscape. These initially barren landscapes will eventually get covered with moss. So, it is no surprise that my Ph.D. research was on the physiological ecology of arctic mosses. I have retained this interest in cryptogam ecology ever since and have worked on ecology of both mosses and lichen.
Brian Heitz, a Ph.D. student is working on the comparative ecology of the feather moss Hylocomium splendens in three biomes, the arctic tundra at Toolik Lake, Alaska, the boreal forest at Bonanza Creek, Alaska, and in the Pacific coastal rain forest, at Andrews, Oregon.
I continue to collaborate with Mats Sonesson at University of Lund in Sweden on lichen and moss research and we have been tackling questions of lichen distributions both on the landscape (alpine and forest habitats) and on trees (above- and below snow-line) and we are presently working on the source of carbon and nitrogen of lichens in the tundra as well as the forest.
The third category of research that I engage in could be labeled “global change research” although some of it is also strongly related to unaltered natural phenomena, such as cold vents and carbon dioxide vents. These natural phenomena and others can be used as surrogates of past and future conditions. For example going ever closer to a carbon dioxide vent one finds plants exposed to increased ambient carbon dioxide partial pressures and by studying them one can make predictions of future conditions. I have carried out such research at a site in western Iceland in collaboration with Walter Oechel and his student Andrea Cook at San Diego State University.
The plants nearest the vent experience elevated atmospheric carbon dioxide partial pressure.
I am presently finalizing research on the opposite gradient, i.e. going toward lower ambient carbon dioxide partial pressures. We know that as we ascend a mountain and the atmospheric carbon dioxide partial pressure drops, plants discriminate less against the heavier isotope of carbon i.e. 13C in carbon dioxide. The environmental cause of this decreased 13C in carbon discrimination has been attributed to either/both decreasing ambient carbon dioxide partial pressures or decreased temperature but their effects have been difficult to tease apart. I have been doing studies in collaboration with Franco Miglietta and Cesare Ravazzi (National Research Council of Italy) at sites in northern Italy where low cold temperature air vents surrounded by alpine plants are found at low altitude. Thus one can look at elevational gradients of 13C in several species of alpine plants as well as the community as a whole and determine if discrimination is temperature dependent.
Halldóra Gunnarsdóttir standing next to a cold air vents at 300 meters above sea level. The vents are in northern Italy.
The plants growing near the cold air vents are otherwise not found below 1700 m asl. Below the notebook is Dryas octopetala.
I plan to continue these avenues of research but I am always open to new ones if they excite me. I am very fortunate to have worked in many beautiful areas with many very intelligent people. I live in an ideal location for these kinds of studies as here on the southern border of the boreal forest, we have unparalleled diversity of habitats and species and relatively little human degradation of the environment. I welcome sharing this experience and these opportunities with other curious scientists and students.