Benthic Communities
Primary production reaching the sea floor is consumed by benthic organisms (animals living in or closely associated with sediments) allowing these communities to flourish in the Chukchi Sea. Prior work in the Chukchi Sea has been broadly focused and smaller-scale information is needed. Thus, invertebrate organisms dwelling in sediments (macrofauna including marine worms, clams, snails, and other small animals) and larger, mobile animals on top of the sediments (megafauna including brittle stars, sea stars, sea cucumbers, crabs, and shrimps) are sampled to understand the ecology of the benthic fauna in the study areas. The study is investigating relationships between invertebrate community composition and environmental characteristics to understand what factors influence community structures. The benthic team is also evaluating invertebrate food-web structure through tissue isotope analysis. Compared to other studies in the area, the smaller scale of the CSESP allows for stronger insights into the geologic and oceanographic factors structuring and influencing benthic animals in the region.
Benthic 2012
The 2012 benthic ecology component of the CSESP investigated the community ecology of invertebrate organisms living within and on top of the sediments in the Greater Hanna Shoal Study Area. We continued investigations of meiofauna, macrofauna, megafauna, and food webs in the area. We also initiated a study of the energy content of benthic communities across the study area.
Arny Blanchard, Ph.D.
Principal Investigator
UAF – Institute of Marine Science
127 O’Neill PO Box 757220
Fairbanks, AK 99775
907-474-1123
alblanchard@alaska.edu
Benthic 2011
The study area of the 2011 CSESP was expanded to encompass an area from Klondike in the south to Hanna Shoal in the north, called the Greater Hanna Shoal Study Area. The benthic ecology team sampled macrofauna, investigated megafauna using digital photography, began a pilot study for meiofauna (very small animals living with sediments), measured caloric content of key walrus prey items, and investigated food webs. Bivalves (walrus prey) were dominant southeast of the Hanna Shoal area and northeast of the Burger study area. Food webs varied noticeably with differences in the type of food reaching the seafloor in each study area during late summer. There were significant variations in the isotopic signature of the dominant polychaete Maldane sarsi among the Klondike, Burger, and Statoil study areas. Indirect effects of variations in water circulation due to topographic changes (high and low spots on the seafloor) are strong, controlling factors of benthic communities in the study area.
Arny Blanchard, Ph.D.
Principal Investigator
UAF – Institute of Marine Science
127 O’Neill PO Box 757220
Fairbanks, AK 99775
907-474-1123
alblanchard@alaska.edu
Benthic 2010
The benthic ecology component of the 2010 CSESP investigated the ecology of benthic communities in the Burger, Klondike, and Statoil (new in 2010) study areas in the northeastern Chukchi Sea. The benthic ecology team also sampled three stations were gray whales were observed feeding and added five stations between Burger and Klondike. The team continued investigation of macrofauna and megafauna community structure and the food web study. We found substantial spatial and temporal variations in biomass and density between the study areas with Burger having greater biomass and density than Klondike. Statoil had similar environmental and biological community characteristics to both Klondike and Burger. Additionally, biomass and density values in Burger and Klondike were higher in 2009 than either 2008 or 2010. The temporal variations in benthic communities coincided with interannual differences in oceanographic conditions. Preliminary results suggested significant differences in food webs between the study areas.
Arny Blanchard, Ph.D.
Principal Investigator
UAF – Institute of Marine Science
127 O’Neill PO Box 757220
Fairbanks, AK 99775
907-474-1123
alblanchard@alaska.edu
Benthic 2009
The benthic ecology component of the 2009 CSESP investigated the ecology of benthic organisms in the Burger and Klondike study areas in the northeastern Chukchi Sea. In our second year of sampling we continued the investigation of macrofaunal and megafaunal community structure and added six coastal stations were gray whales were observed feeding in 2009. We found large differences in the biomass and density between the study areas for both macro- and megafauna with Burger, again, having greater biomass and density than Klondike. The offshore study areas were dominated by polychaetes and bivalves and the coastal Mammal-feeding stations were dominated by amphipods, the favored food of gray whales. An investigation of differences in food webs between the study areas was initiated in 2009.
Arny Blanchard, Ph.D.
Principal Investigator
UAF – Institute of Marine Science
127 O’Neill PO Box 757220
Fairbanks, AK 99775
907-474-1123
alblanchard@alaska.edu
Benthic 2008
The benthic ecology component of the 2008 CSESP investigated the ecology of macrofauna in the Burger and Klondike study areas. In our first year, we focused on spatial variations of benthic communities and community structure, and the environmental variables associated with community variations. The soft sediments of the study areas were dominated by the marine worm (polychaete) Maldane sarsi and the bivalve Ennucula tenuis polychaetes and bivalves were dominant across both areas. We found large differences in the biomass and density between the study areas with Burger (to the west of a biological hotspot) having greater biomass and density than Klondike, in spite of small differences in environmental gradients in water depth, sediment grain-size, and bottom-water temperature.
Arny Blanchard, Ph.D.
Principal Investigator
UAF – Institute of Marine Science
127 O’Neill PO Box 757220
Fairbanks, AK 99775
907-474-1123
alblanchard@alaska.edu