The structure of an arctic shallow water benthic community : effects of ice gouging

• Main Author: Braun, Gary Michael
• Other Authors: Carey, Andrew G., Boucot, A. J., Taghon, Gary, College of Oceanography, Oregon State University. Graduate School
• Format: Master Thesis
• Language: English; unknown
• Published: Oregon State University
• Subjects: Benthos > Beaufort Sea; Beaufort Sea
• Online Access: https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/5999n601r

The shallow water benthic habitat of the SW Beaufort Sea is frequently gouged by the keels of ice pressure ridges. This natural physical disturbance was hypothesized to be an important factor affecting the structure of the benthic community. Smith-McIntyre grab samples were taken from three discrete gouge axes and from control areas on both sides of each gouge to examine this hypothesis. Significantly lower abundances were noted for total macrofauna and at the major taxa level inside two of the three gouge axes. Diversity and evenness indices increased inside the axes of all three gouges. At the species level, differences existed between gouge areas, but in general lower abundances were also found for many of the dominant species. A few species abundances were significantly higher inside the gouge axes. These differences were not dependent on differences in gouge depth, age or associated sediment parameters. Thus ice gouging is thought to be important in structuring the associated benthic assemblages at these discrete disturbance sites. The generality of the significance of ice gouging along the entire Beaufort coast is considered. Comparisons among gouges by cluster analyses of both the species and sediment data each yielded three groups of similar station aggregations suggesting a strong correlation between species distributions and sediment characteristics. However, factors such as water depth and relative gouge age, also correlate with the observed cluster groups. Therefore, one factor alone was unable to account for the observed patterns. Interactions of the many physical factors in this environment are proposed to explain the observed distributions. The physical action of ice gouging directly impacts the benthic assemblages by reducing abundances and indirectly by changing the associated sediment parameters which can influence animal distributions.