Presentation on theme: "Use of regularly migrating non-biological platforms as vehicles for spatio-temporal sampling of Southern Ocean systems Simon Wright, Brian Griffiths, Bronte."— Presentation transcript:
Use of regularly migrating non-biological platforms as vehicles for spatio-temporal sampling of Southern Ocean systems Simon Wright, Brian Griffiths, Bronte Tilbrook, Steve Rintoul, Alain Poisson
How to model microbial populations? Recognize different types of communities Key species and associations When and where do they occur? Time of season Oceanographic conditions MLD, nutrients, ice, etc Parameterize the community properties Primary production, respiration Aggregation Sedimentation Size distribution
What would a Southern Ocean Observing System look like?
Bloom dynamics at mid latitude (53- 60ºS) 2002 - 2003 Bloom in Feb about 1 ug Chl a/ L Dominant species – F. kerguelensis, Phaeocystis, Trichotoxon, Thalassiothrix, Pseudonitzschia 2003 – 2004, 2004 – 2005 (Typical) Bloom in Dec - Jan about 0.8 - 1 ug Chl a/ L Dominant species F. kerguelensis, Pseudonitzschia, Trichotoxon, Chaetoceros dichaeta
Bloom dynamics at mid latitude (53- 60ºS) The late bloom in 2002-2003 was associated with relatively warm, very low salinity water This water had low nutrient concentrations. A bloom developed only after nutrient concentrations increased
Conclusions Regular sampling of Southern Ocean from lAstrolabe identified seasonal patterns in microbial populations –relationship to carbon dioxide uptake –Relationship to nutrient drawdown Substantial interannual differences in bloom dynamics appeared to be driven by seawater chemistry An anomalous late bloom developed only after nutrient concentrations increased in a large area of warm low salinity water. A small subset of total data: made possible by repeated sampling of many parameters in a collaborative program