Skip to Main Content

Cruise Data: DBO related time series
2010 Pilot Study | 2011 Pilot Study | 2012 Pilot Study | Related time series | Preliminary Findings & challenges

DBO Related Time Series

West Bering/Chukchi benthis communities 1970-2010
[updated and modified from Grebmeier et al. 2006]
  • “foot prints” of high benthic biomass reflect pelagic-benthic coupling and export of carbon to sediments
  • infaunal dominated by amphipods, bivalves, polychaetes, and sipunculids

map of bering/chukchi area

 

The highest benthic biomass stations occur under Anadyr water on the western side of the Pacific Arctic system from the northern Bering Sea into the northern Chukchi Sea. There are “footprints” of high benthic biomass associated with high water column productivity and export production of organic carbon descending to the sediments. Infauna is dominated by amphipods, bivalves, polychaetes and sipunculids.

 

Time series date from DBO site 1 in the northern Bering Sea indicate a decline in sediment oxygen update, an indicator of reduced carbon supply to the benthos south of St. Lawrence Island. This figure updates data since 2004 that was published in Science.
Time series data from DBO site 1 in the northern Bering Sea indicate a decline in sediment oxygen update, an indicator of reduced carbon supply to the benthos south of St. Lawrence Island. This figure updates data since 2004 that was published in Science (Grebmeier et. al., 2006, Science 311).

 

The decrease in organic supply to the benthos in the St. Lawrence Island polynya region corresponds with a decline in the dominant nuculanid bivalves during the 1990s to present. Notably there has been an increase in the smaller, less nutritious nuculid bivalves at two of the time series sites where there has been a fining of sediments in the region.

There has been a decline in ampeliscid amphipods from the 1990's to 2000, with some time series stations in rebound, although the overall spatial "footprint" is declining (see "Footprint" figure below).

 

There has been a decline in ampeliscid amphipods from the 1990s to 2000, with some time series stations in rebound, although the overall spatial “footprint” is declining (see slide #21). Note that one of the times series site has changed from ampeliscid amphipods to ampharetid polychaetes with a fining of the sediments (change to smaller sediment grain size).

There has been a decline in ampeliscid amphipods from the 1990s to 2000, with some time series stations in rebound, although the overall spatial “footprint” is declining (see slide #21). Note that one of the times series site has changed from ampeliscid amphipods to ampharetid polychaetes with a fining of the sediments (change to smaller sediment grain size).

  • decline ampeliscid amphipods to 2000, with some rebound, although “footprint” declining
  • note that one site changed from ampelisid amphipods to ampharetid polychaetes

 

Dominant infauna at DBO site #2 in the Chirikov Basin of the northern Bering Sea. Notably the “footprint” of ampeliscid amphipod prey is contracting spatially, thus although biomass is stabilizing, the overall area for prey for feeding gray whales has been reduced.

Dominant infauna at DBO site #2 in the Chirikov Basin of the northern Bering Sea. Notably the “footprint” of ampeliscid amphipod prey is contracting spatially, thus although biomass is stabilizing, the overall area for prey for feeding gray whales has been reduced.

 

Time series of station benthic infaunal biomass at DBO site #3 in the SE Chukchi Sea. There are some changes and declines in benthic infaunal biomass, except UTN5 (DBO #3 “hotspot” station at the head of Herald. Valley. We have also seen a shift at station UTN1 from bivalves to sand dollars since the 1970s.

Time series of station benthic infaunal biomass at DBO site #3 in the SE Chukchi Sea. There are some changes and declines in benthic infaunal biomass, except UTN5 (DBO #3 “hotspot” station at the head of Herald. Valley). We have also seen a shift at station UTN1 from bivalves to sand dollars since the 1970s.

  • changes and some decline in benthic infaunal biomass
  • except UTN5 (DBO “hotspot” station at head of Herald Valley
  • also UTN1 shift bivalves to sand dollars

 

Northward increase in benthis infaunal abundance and biomass at DBO4

 

DBO5 high benthic biomass and diversith at head of barrow canyon