Co-variability of salinity, nutrients and coastal currents in the northern Gulf of Mexico and its impact on plankton biomass

The northern Gulf of Mexico (GoM) is a region strongly influenced by river discharges of freshwater and nutrients, which promote a highly productive coastal ecosystem that host commercially valuable marine species. A new study appeared in Scientific Report utilized a regional ocean-biogeochemical model and observations to show that El Niño – Southern Oscillation (ENSO) is a main driver of the interannual variability in salinity, nutrients and plankton biomass during winter and spring. Their analysis of the model simulation further showed significant coastal circulation anomalies driven by changes in salinity and winds. The coastal circulation anomalies in turn largely determine the spatial extent and distribution of the ENSO-induced plankton biomass variability. These findings highlight that ENSO-induced changes in salinity, plankton biomass, and coastal circulation across the northern GoM are closely interlinked and may significantly impact the abundance and distribution of fish and invertebrates.

Figure 4 from Gomez et al. (2018): EOF analysis of chlorophyll anomalies. (a, b) First EOF mode of surface model chlorophyll (a) and SeaWiFS chlorophyll (b). (c) Principal component associated with the first EOF mode of model, SeaWiFS, and MODIS chlorophyll. Correlation coefficient between model and satellite PC1 series is indicated in (c).

Gomez, F. A., Lee, S.-K., Hernandez, F. J., Chiaverano, L. M., Muller-Karger, F. E., Liu, Y., & Lamkin, J. T. (2019). ENSO-induced co-variability of Salinity, Plankton Biomass and Coastal Currents in the Northern Gulf of Mexico. Scientific reports, 9(1), 178. https://www.nature.com/articles/s41598-018-36655-y

Gomez, F. A., Lee, S.-K., Liu, Y. Hernandez, F. J., Muller-Karger, F. E., and Lamkin, J. T. (2018). Seasonal patterns in phytoplankton biomass across the northern and deep Gulf of Mexico: A numerical model study. Biogeosciences, 15, 3561-3576. https://doi.org/10.5194/bg-15-3561-2018. https://www.biogeosciences.net/15/3561/2018/bg-15-3561-2018.pdf