Environmental Variability and Oceanographic Dynamics of the Central and Southern Coastal Zone of Sonora in the Gulf of California

Abstract

This study analyzed monthly and inter-annual variability of mesoscale phenomena, including the El Niño Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO) climate indexes and wind intensity considering their influence on sea surface temperature (SST) and chlorophyll a (Chl-a). These analyses were performed to determine the effects, if any, of climate indexes and oceanographic and environmental variability on the central and southern coastal ecosystem of Sonora in the Gulf of California (GC). Monthly satellite images of SST ( • C) and Chl-a concentration were used with a 1-km resolution for oceanographic and environmental description, as well as monthly data of the climate indexes and wind intensity from 2002-2015. Significant differences (p > 0.05) were observed while analyzing the monthly variability results of mesoscale phenomena, SST and Chl-a, where the greatest percentage of anti-cyclonic gyres and filaments was correlated with a greater Chl-a concentration in the area of study, low temperatures and, thus, greater productivity. Moreover, the greatest percentage of intrusion was correlated with the increase in temperature and cyclonic gyres and a strong decrease of Chl-a concentration values, causing oligotrophic conditions in the ecosystem and a decrease in upwelling and filament occurrence. As for the analysis of the interannual variability of mesoscales phenomena, SST, Chl-a and winds, the variability between years was not significant (p > 0.05), so no correlation was observed between variabilities or phenomena. The results of the monthly analyses of climate indexes, environmental variables and wind intensity did not show significant differences for the ENSO and PDO indexes (p > 0.05). Nonetheless, an important correlation could be observed between the months of negative anomalies of the ENSO with high Chl-a concentration values and intense winds, as well as with low SST values. The months with positive ENSO anomalies were correlated with high SST values, low Chl-a concentration and moderate winds. Significant inter-annual differences were observed for climate indexes where the years with high SST values were related to the greatest positive anomaly of ENSO, of which 2002 and 2009 stood out, characterized as moderate Niño years, and 2015 as a strong El Niño year. The years with the negative ENSO anomaly were related to the years of lower SST values, of which 2007SST values, of which -2008SST values, of which and 2010SST values, of which -2011 stood out, characterized as moderate Niñas. Thus, variability associated with mesoscale oceanographic phenomena and seasonal and inter-annual variations of climate indexes had a great influence on the environmental conditions of the coastal ecosystem of Sonora in the Gulf of California.

Sea Surface Temperature (SST) Variability of the Eastern Coastal Zone of the Gulf of California

“…They found winter conditions from December to April and summer conditions from June to October, with an increase of SST from 16 • in February-March to 31 • C in August. The SST values were similar to Valenzuela-Sánchez [23], Soto-Mardones et al [22] and García-Morales et al [29], as well as in this study. Bernal et al [50] report that the variability in this region is caused by the effects of seasonal winds and the oceanographic influence from the Pacific Ocean, the seasonal coastal winds develop a sea surface circulation along the Eastern Coast, to the south during October-March and to the north during June-September [8].…”

“…This gradient from south to north is similar to the results for whole Gulf of California described by Soto-Mardones et al [22], Escalante et al [24] and Hidalgo-González and Álvarez-Borrego [43]. This SST distribution, during the warm period, can be explained by the fact that the direct communication with the Tropical Pacific Ocean allows the entry of Equatorial Surface Water [29,44], and inside the Gulf of California it is modified by greater solar irradiance and evaporation effects [42], generating this gradient. During the cold period, SST decrease inside the Gulf by physical dynamics such tidal and wins mixing [25], mainly in the Midriff Islands and North Regions.…”

“…Interannual variability was associated with the cyclonic north equatorial circulation composed of the North Equatorial Countercurrent, the North Equatorial Current and the Costa Rica Current [27], El Niño-La Niña, and also with the Interdecadal Variability of the Pacific Ocean [28]. García-Morales et al [29] analyzed meso-scale phenomena, and their influence on SST in the southern and central region of the coastal area of the State of Sonora. They showed that environmental conditions in the Gulf of California have a great influence, seasonal and interannual, of the meteorological and oceanographic processes variability of the Pacific Ocean.…”

Heterogeneous Perceptions of Social-Ecological Change Among Small-Scale Fishermen in the Central Gulf of California: Implications for Adaptive Response

“…A number of important fisheries declined during ocean warming associated with the strong El Niño events of 1982-1983 and 1997-1998, but recovery was observed in both cases during subsequent La Niña conditions as cool, productive water returned to the region (Bakun et al, 2010;Lluch-Cota et al, 2010). However, alongside the return of El Niño conditions in 2009-2010 and 2015-2016, persistent ocean warming (Hoving et al, 2013;Frawley, 2019) has been observed across the central Gulf of California alongside decreasing upwelling and primary productivity (as inferred by chlorophyll a) along the eastern coast (Robinson et al, 2016;García-Morales et al, 2017). Though research results remain disaggregated, observations concerning changes in the distribution and abundance of marine mammals (Elorriaga-Verplancken et al, 2016), seabirds , sea turtles (Zavala-Norzagaray et al, 2017), and other marine taxa (Hoving et al, 2013;Fernández-Rivera Melo et al, 2018) suggest that the impacts on marine animals have been significant.…”

Marine Heat Waves and the Influence of El Niño off Southeast Queensland, Australia

“…SST variability due to ENSO has been shown to globally impact on ecosystem structures on various spatial scales. This includes the oceans surrounding Australia (Pearce and Feng, 2013;Sprogis et al, 2017;Arias-Ortiz et al, 2018;Benthuysen et al, 2018;Stuart-Smith et al, 2018), the Peruvian Upwelling Ecosystem (Quispe-Ccalluari et al, 2018), the Gulf of California (García-Morales et al, 2017) and the northeastern Arabian Sea (Vidya and Kurian, 2018).…”