Byfjord status in May 2011

Vattenprofil för Byfjorden den 18 maj 2011. Bilden visar temperatur (röd), salthalt (svart) och syrekoncentration (blå) från ytan till cirka 45 meters djup. Den streckade linjen visar en mätning utförd den 15 mars 2011. Klicka på bilden för större version.

After one months pause the monthly measurements were resumed in the Byfjord on May 18. The water temperature is about 12 degrees down to a depth of about 11 metres, and decline rapidly thereafter. The deepwater is approximately 7-8 degrees.

The salinity is somewhat lower in May than in Match, but no large changes have occured in the deepwater.

Due to optode malfunction, manually titrated oxygen concentrations have been used in the plot, indicated with dots. Compared to March, the oxygen concentrations is lower in the surface water, probably due to a thermal effect. However, down to about 30 metres, the oxygen levels have increase, indicating an inflow has taken place.

Annual maintenance of deployed instruments

The instruments in the Byfjord have been recovered for an annual maintenance. This means that the hourly updated graphs for salinity, temperature, oxygen and current measurements will be offline for a few days. We hope to redeploy the instruments in late May or early June.

Although the instruments are designed to withstand a harsh marine environment for an extended period of time, we need to recover them for maintenance at least once per year. Free swimming larvae quickly colonise the surface of our instruments, potentially preventing proper measurements to be made. During the service window we will continue with our monthly samples of oxygen and nutrients in the Byfjord, as well as making a weekly CTD cast in the fjord for temperature, salinity and oxygen.