Alaska Science Center
We are particularly interested in the effects of long-term changes in water temperature and how those changes affect marine ecosystems. The top figure shows sea surface temperature anomalies in Kachemak Bay Alaska since the early 1960's. "Anomalies" reveal the difference in temperatures from the long-term average. Values above zero mean that temperatures were warmer than average, while values below zero were colder than average. The blue lines and dots show the actual mean winter (November-March) temperature anomalies in Kachemak Bay, while the red line represents values smoothed over 5 consecutive years (to show the underlying trend). What we found is that water temperatures have been warmer than average throughout most of the 1980's and 1990's. Particularly warm years were observed when El Nino occurred in the Pacific (for example in 1998). These long-term fluctuations in temperature have a profound effect on fish and seabird populations.
Between 1997 and 1999 we measured temperature and salinity in the watercolumn during mid-summer across lower Cook Inlet (see map for transect details). Satellite imagery had indicated that there was a cold water upwelling in that area. Upwellings are important to marine ecosystems because they tend to bring cold, nutrient rich waters from the ocean bottom close to the surface where they can be utilized by phytoplankton. The profile of our cross inlet transect (shown below) clearly indicated the cold, well mixed area (CIT-6 through CIT-9, cold waters are indicated in shades of yellow, green, and blue). These profiles also allow us to examine the degree and extent of stratification on the western portion of the inlet (CIT-2 through CIT-6) and the mouth of Kachemak Bay (CIT-9 through CIT-12). These measurements help us identify marine habitats which can vary in time and space. We also collected salinity and flourometry data along this transect.
Sea Surface Temperature Anomalies in Kachemak Bay, Alaska.
Profile of Ocean Temperatures across Cook Inlet