Oceanographic regime shift during 1997 in Disko Bay, Western Greenland

Abstract

Data from a long time series of temperature, salinity, and nutrient measurements in Disko Bay (West Greenland) reveal a marked change in the water characteristics during recent years. Seasonal dynamics in the upper 150 m of the water column were highly affected by the seasonality in meteorological conditions, while the deeper water strata were more stable and were primarily influenced by large-scale circulation patterns. There was a marked increase in the average water temperatures at 200-m depth in spring 1997, with the long-term average increasing from 1.30uC to 2.25uC. Weekly data from 1996 to 1997 show that the sudden change in bottom water occurred in April 1997, due to the inflow of a larger proportion of North Atlantic water, which propagated north along the coast before entering the bay. Further support for this inflow was found when tracing the relative proportion of Atlantic water in the bay, using inorganic nutrients. These changes in the oceanography of the bay will not only lead to further glacial retreat but will also affect the local marine ecosystem by changing the relative dominance of major copepod species that overwinter in bottom waters of the bay.

Growth and bioactive secondary metabolites of arctic Protoceratium reticulatum (Dinophyceae)

“…In any case, with a doubling time of about 10 to 7 days for the temperature range of 1-5 8C is seems unlikely that P. reticulation will be able to form blooms in arctic areas, given the short duration of the growth season and prevailing low water temperature in the Arctic. In Disco Bay, Greenland, the area where all but one P. reticulatum isolates were collected, summer (JuneAugust) surface water (0-50 m) temperature ranged between À1.5 8C and 10.3 8C for the period between 1924 and 2010 (Hansen et al, 2012) with higher water temperatures of 5 to 10 8C recorded only during the late phase of the growth season.…”

Copepod Life Strategy and Population Viability in Response to Prey Timing and Temperature: Testing a New Model across Latitude, Time, and the Size Spectrum

“…This represents a cold, highice state of the system, compared with more recent years in which the spring bloom is earlier (e.g., 2008, Figure 8, Swalethorp et al, 2011) and the deep layer is warmed by Atlantic water intrusions (Hansen et al, 2012). This particular year was chosen because measurements of prey availability and Calanus response by Madsen et al (2001) were particularly complete and coordinated.…”

Induction of domoic acid production in the toxic diatom Pseudo-nitzschia seriata by calanoid copepods

“…The copepods Calanus finmarchicus and C. hyperboreus were collected from Disko Bay (69 • 14 N, 53 • 23 W) at a 300-m-deep monitoring station (Madsen et al, 2001;Hansen et al, 2012) during the spring bloom in April 2012. Disko Bay is located on the western coast of Greenland.…”