Time-series wavelet transform exposes South Atlantic Ocean changes during the last 40 years

ARIAS, ANDRÉS HUGO; ALBERDI, ERNESTO; FREIJE, R.H.; MARCOVECCHIO, JORGE

Qingdao

Simposio; Change and Sustainability of the North Pacific; 2015

North Pacific Marine Science Organization

Climate change is creating a dynamic of continuous changes in ecosystems. Generally, the expected consequencesof these changes are global; however, the occurrence of extreme events and specific environmental problemsare usually local or regional phenomena. One of the keys to uncover climate-driven changes is the long-termtime-series of observations. While there are a number of long-term biological time-series on land, there arerelatively few in marine environments. This is highlighted by the fact that the Intergovernmental Panel on ClimateChange (IPCC) noted 28586 significant biological changes in terrestrial systems, but only 85 from marine andfreshwater systems. The present research deals with this gap, focusing on an area which holds scarce to nulllong-term research on ocean observation and climate driven changes: the South Atlantic Ocean. From the resultsof the analysis of up to 40 years of oceanographic physicochemical variables measured at the Bahia BlancaEstuary, previously unknown underlying trends were uncovered. In order to test the variables? trends throughoutseveral time-scales, the continuous wavelet transform (CWT) was used to divide the continuous-time functioninto wavelets. Moreover, the use of Cross Wavelet Correlation (CWC) allowed the relationship between thevariables to be highlighted throughout different time-scales. After that, a correlation analysis which linked theocean observations to biological documented changes was assessed. As a result, novel hypotheses were raised inthe field of phytoplankton and zooplankton assemblages climate-driven control, crustaceans catches and fisheriesrecruitment