Sea Surface Temperature Influence on Terrestrial Gross Primary Production along the Southern California Current.

Janet J Reimer,Rodrigo Vargas,David Rivas,J Martin Hernandez-Ayon,Gilberto Gaxiola-Castro,Ruben Lara-Lara,Moncho Gomez-Gesteira

doi:10.1371/journal.pone.0125177

Abstract

Some land and ocean processes are related through connections (and synoptic-scale teleconnections) to the atmosphere. Synoptic-scale atmospheric (El Niño/Southern Oscillation [ENSO], Pacific Decadal Oscillation [PDO], and North Atlantic Oscillation [NAO]) decadal cycles are known to influence the global terrestrial carbon cycle. Potentially, smaller scale land-ocean connections influenced by coastal upwelling (changes in sea surface temperature) may be important for local-to-regional water-limited ecosystems where plants may benefit from air moisture transported from the ocean to terrestrial ecosystems. Here we use satellite-derived observations to test potential connections between changes in sea surface temperature (SST) in regions with strong coastal upwelling and terrestrial gross primary production (GPP) across the Baja California Peninsula. This region is characterized by an arid/semiarid climate along the southern California Current. We found that SST was correlated with the fraction of photosynthetic active radiation (fPAR; as a proxy for GPP) with lags ranging from 0 to 5 months. In contrast ENSO was not as strongly related with fPAR as SST in these coastal ecosystems. Our results show the importance of local-scale changes in SST during upwelling events, to explain the variability in GPP in coastal, water-limited ecosystems. The response of GPP to SST was spatially-dependent: colder SST in the northern areas increased GPP (likely by influencing fog formation), while warmer SST at the southern areas was associated to higher GPP (as SST is in phase with precipitation patterns). Interannual trends in fPAR are also spatially variable along the Baja California Peninsula with increasing secular trends in subtropical regions, decreasing trends in the most arid region, and no trend in the semi-arid regions. These findings suggest that studies and ecosystem process based models should consider the lateral influence of local-scale ocean processes that could influence coastal ecosystem productivity.

Highlights

Many land and ocean processes are linked through connections in the atmosphere
Results are organized from north to south along the peninsula in order to emphasize the spatial differences between transects (Fig 1)
Along each transect we focus on a synthesis of the overall characteristics, rather than a detailed comparison of site specific differences

Summary

Introduction

Many land and ocean processes are linked through connections in the atmosphere Synopticscale atmospheric events such as El Niño/Southern Oscillation (ENSO; 2 to 7 year cycles), Pacific Decadal Oscillation (PDO), and North Atlantic Oscillation (NAO; decadal cycles) are known to influence the global terrestrial carbon cycle [1,2]. ENSO and PDO are the predominant atmospheric phenomena which impact both marine and terrestrial ecosystems along the Pacific coast of North America [3]. Evidence suggests that connective processes influence regional-scale gross primary production (GPP) in coastal ecosystems. It is unknown, how smaller scale processes, including those of marine origin (e.g., local upwelling events) could influence local-to-regional variability of GPP

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