Distribution of Arctic and Pacific copepods and their habitat in the northern Bering and Chukchi seas
The advection of warm Pacific water and the reduction in sea ice in the western Arctic Ocean may influence the abundance and distribution of copepods, a key component of food webs. To quantify the factors affecting the abundance of copepods in the northern Bering and Chukchi seas, we constructed hab...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-08-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/13/4555/2016/bg-13-4555-2016.pdf |
| Summary: | The advection of warm Pacific water and the reduction in sea ice in the
western Arctic Ocean may influence the abundance and distribution of
copepods, a key component of food webs. To quantify the factors affecting
the abundance of copepods in the northern Bering and Chukchi seas, we
constructed habitat models explaining the spatial patterns of large and
small Arctic and Pacific copepods separately. Copepods were sampled using
NORPAC (North Pacific Standard) nets. The structures of water masses indexed by principle
component analysis scores, satellite-derived timing of sea ice retreat,
bottom depth and chlorophyll <i>a</i> concentration were integrated into
generalized additive models as explanatory variables. The adequate models
for all copepods exhibited clear continuous relationships between the
abundance of copepods and the indexed water masses. Large Arctic copepods
were abundant at stations where the bottom layer was saline; however they
were scarce at stations where warm fresh water formed the upper layer. Small
Arctic copepods were abundant at stations where the upper layer was warm and
saline and the bottom layer was cold and highly saline. In contrast, Pacific
copepods were abundant at stations where the Pacific-origin water mass was
predominant (i.e. a warm, saline upper layer and saline and a highly saline
bottom layer). All copepod groups showed a positive relationship with early
sea ice retreat. Early sea ice retreat has been reported to initiate spring
blooms in open water, allowing copepods to utilize more food while
maintaining their high activity in warm water without sea ice and cold
water. This finding indicates that early sea ice retreat has positive
effects on the abundance of all copepod groups in the northern Bering and
Chukchi seas, suggesting a change from a pelagic–benthic-type ecosystem to
a pelagic–pelagic type. |
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| ISSN: | 1726-4170 1726-4189 |