Phytoplankton Community Structure in 2011–2013 Compared to the Extratropical Warming Event of 2014–2015

Abstract

Coastal waters of the Northern California Current experienced “normal” ocean conditions in 2011–2012, weak upwelling in 2013–2014, then suddenly warmed in September 2014. The response of phytoplankton community structure to contrasting ocean conditions was determined from samples collected off Newport, Oregon. Cluster analysis identified three prominent phytoplankton community types: one that occurred during the upwelling season characterized by the highest abundance and diversity of diatoms, a preupwelling/relaxation community characterized by lower abundance, lowest diversity of diatoms and dinoflagellates, and another one associated with the warm anomalies from September 2014 through 2015 with reduced diatom abundance and diversity but the highest dinoflagellate diversity. The changes of diatom and dinoflagellate community were correlated with local factors (silicate, silicate: nitrate ratios, temperature, and salinity), and with the Pacific Decadal Oscillation.

Regional Structure in the Marine Heat Wave of Summer 2015 Off the Western United States

“…This prolonged MHW in the northeast Pacific eventually overlapped with the 2015-16 El Niño (Jacox et al, 2016;Zaba and Rudnick, 2016;Chao et al, 2017;Zaba et al, 2018), though the impacts of the El Niño were weaker than usual along western North America (Barnard et al, 2017;Frischknecht et al, 2017;Paek et al, 2017). This MHW caused major damage to economically important fisheries and other ecosystems from Alaska through California associated with species shifts (Whitney, 2015;Cavole et al, 2016;Auth et al, 2017;Daly et al, 2017;Peterson et al, 2017;Du and Peterson, 2018;Gomez-Ocampo et al, 2018;Kahru et al, 2018) and an unprecedentedly large bloom of toxic algae that spanned the entire coastline (McCabe et al, 2016).…”

Warm Events Induce Loss of Resilience in Organic Carbon Production in the Northeast Pacific Ocean

“…In 2014 and 2015, the northern Gulf of Alaska exhibited low zooplankton abundance (McKinstry & Campbell, 2018). The development of the Arc pattern along the west coast of United States between 2014 and 2015 altered the local phytoplankton community structure (Du & Peterson, 2018), with elevated SSTs stimulating harmful algae blooms in the northern California Current (McKibben et al, 2017;Zhu et al, 2017). The development of the Arc pattern along the west coast of United States between 2014 and 2015 altered the local phytoplankton community structure (Du & Peterson, 2018), with elevated SSTs stimulating harmful algae blooms in the northern California Current (McKibben et al, 2017;Zhu et al, 2017).…”

“…The warm anomalies impacted the Bering Sea from 2014 until 2016 by shifting phytoplankton blooms to early spring (Stabeno et al, 2017), similar to the early increase in phytoplankton abundance observed in the Gulf of Alaska in 2014 (Peña et al, 2019) and early NCP from this work (Figure 4c). The development of the Arc pattern along the west coast of United States between 2014 and 2015 altered the local phytoplankton community structure (Du & Peterson, 2018), with elevated SSTs stimulating harmful algae blooms in the northern California Current (McKibben et al, 2017;Zhu et al, 2017). Still, in 2015, there was a decline in zooplankton stocks off the coast of Mexico and a shift in the vertical distribution of fish larvae in response (Sánchez-Velasco et al, 2017).…”

“…The period between 2013 and 2016 was remarkable for the northeast Pacific as it involved consecutive warm events, starting with "the Warm Blob" that developed in the central Gulf of Alaska and concluding with a strong El Niño (Bond et al, 2015;Hu & Fedorov, 2016). These events severely reduced the vertical mixing for two consecutive winters (Bond et al, 2015), impacting ecosystem functions ranging from primary to fisheries productivity (Du & Peterson, 2018;McKibben et al, 2017;Peterson et al, 2017;Sánchez-Velasco et al, 2017). From a biogeochemical perspective, the thinning and increased buoyancy of the mixed layer over consecutive winters should have been fundamental in regulating primary production and, consequently, net organic carbon production (i.e., NCP) and its potential for export.…”

Developing a Social–Ecological–Environmental System Framework to Address Climate Change Impacts in the North Pacific

“…As these warm near-surface waters were advected to and impacted coastal waters, the enhanced vertical stratification reduced the efficacy of coastal upwelling to supply nutrients to the euphotic zone which negatively impacted coastal productivity . The combination of reduced primary productivity and the presence and persistence of unusually warm waters led to significant disruptions in the California Current ecosystem (Cavole et al, 2016), including reduced phytoplankton abundance and production (Du and Peterson, 2018;Gómez-Ocampo et al, 2018), a coastwide toxic algal bloom (McCabe et al, 2016;Ryan et al, 2017), reduced biomass of copepods and euphausiids and high abundance of oligotrophic doliolids (Peterson et al, 2017), the massive mortality of a planktivorous seabird (Jones et al, 2018), and substantial changes in species distributions and community composition across multiple trophic levels (Cavole et al, 2016;Santora et al, 2017;Brodeur et al, 2019) .…”