Home Projects Information Roadmap

A ten-year time series from Monterey Bay, California: Seasonal, interannual and long-term patterns

L O N G -T E R M   T R E N D S

newtrends2.gif (90261 bytes)Fig. 5. Long term trends for upwelling index, winds and currents, SST, temperature at 60 m, sea surface salinity, sigma-t, surface nitrate, nitrate at 60 m, surface chlorophyll, integrated primary production, centric diatoms, pennate diatoms, dinoflagellates, and small phytoplankton (less than 5 m) for the study period. The trends suggest increasing equatorward winds during the spring and increasing poleward winds during the winter. The equatorward surface currents are increasing in strength and the poleward undercurrent is as well. SST is increasing at a rate of 7.9C per 100 years, salinity, density, subsurface nitrate, chlorophyll, primary production, and centric diatoms are all decreasing. Dinoflagellates and the small phytoplankton are increasing.

Winds and currents

The winds at 46012 do not show any long-term trend. However, when trends are analyzed by season there are increasing equatorward winds during the winter (more and stronger storms) and increasing poleward winds during the spring. The surface currents are increasing equatorward and the deeper currents are increasing poleward (Fig 5).

Temperature and salinity

Temperature at the surface and 60-meters increased over the period of study. SST increased at the rate of 7.9C per 100 years. Salinity and density have both decreased (Fig 5).

Nutrients

Nitrate at the surface has an increasing trend and nitrate subsurface has a decreasing trend (Fig 5).

Chlorophyll and primary production

Chlorophyll and primary production are decreasing over the period of study. Chlorophyll is decreasing at a faster rate than production (Fig 5), as the decrease in this property has been tempered by an increase in the productivity index (production normalized to chlorophyll).

Phytoplankton taxonomic groups

Centric and pennate diatom biomass have decreased over the period of study. Dinoflagellates and the small phytoplankton have increased (Fig 5).

 

Next: Conclusions

footer2.jpg (18900 bytes)

 Last Updated: Friday, June 23, 2000