全球变化知识资源中心

The Distributed Biological Observatory (DBO) is a change detection array for select ecosystem variables along eight sampling transects in the Pacific Arctic Region (PAR). The overall objective of the DBO is to provide for the detection and consistent monitoring of the biophysical responses to major reductions in seasonal sea ice and concomitant increases in seawater temperatures observed across the region. A key uncertainty is how the PAR marine ecosystem is responding to these shifts in the timing of spring sea-ice retreat and/or delays in fall sea-ice formation. Variations in upper ocean hydrography, stratification, light penetration, planktonic production, pelagic-benthic coupling, and sediment carbon cycling are all influenced by sea ice and temperature changes. Observations of reduced sea ice extent/duration and seawater warming are linked to shifts in species composition and abundance, as well as northward range expansions in some upper trophic predators (e.g. humpback whales and commercially harvested fish), generally with negative impacts on ice-dependent species such as ice-associated seals and walruses. Some distributional shifts may be driven by changes in lower trophic level productivity that directly cascade into upper trophic levels. This special issue is a result of the international effort by participating scientists to implement a coordinated DBO that will meet these needs to understand the ecosystem responses to changing sea ice and thermal regimes. The key geographical focus is on the biologically productive waters in the PAR that are influenced by the inflow of North Pacific water through Bering Strait. Papers in this volume are based upon selected biological measurements at multiple trophic levels, together with appropriate hydrographic surveys and satellite observations. The DBO is developing into a significant national and international change detection resource for the identification and consistent monitoring of marine biophysical responses to climate change, with ongoing plans to expand into a pan-Arctic biological observing network.