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2022 marked the third consecutive La Niña and extended the longest consecutive stretch of negative Oceanic Niño Index since 1998-2001. While physical and biological conditions in winter and spring largely adhered to prior La Niña conditions, summer and fall were very different. Similar to past La Niña events, in winter and spring coastal upwelling was either average or above average, temperature average or below average, salinity generally above average. In summer and fall, however, upwelling and temperature were generally average or slightly below average, salinity was close to average and chlorophyllawas close to average. Again, as during prior La Niña events, biomass of northern/southern copepods was above/below average off Oregon in winter, and body size of North Pacific krill in northern California was above average in winter. By contrast, later in the year the abundance of northern krill dropped off Oregon while southern copepods increased and body sizes of North Pacific krill fell in northern California. Off Oregon and Washington abundances of market squid and Pacific pompano (indicators of warm, non-typical La Niña conditions) were high. In the 20thcentury, Northern anchovy recruitment tended to be high during cold conditions, but despite mostly warm conditions from 2015-2021 anchovy populations boomed and remained high in 2022. Resident seabird reproductive success, which tended in the past to increase during productive La Niña conditions was highly variable throughout the system as common murre and pelagic cormorant, experienced complete reproductive failure at Yaquina Head, Oregon while Brandt’s cormorant reproduction was average. At three sampling locations off central California, however, common murre reproduction was close to or above average while both pelagic and Brandt’s cormorant were above average. California sealion reproduction has been above average each year since 2016, and pup weight was also above average in 2022, likely in response not to La Niña or El Niño but continuous high abundance of anchovy. The highly variable and often unpredictable physical and biological conditions in 2022 highlight a growing recognition of disconnects between basin-scale indices and local conditions in the CCE. “July-December 2022 is the biggest outlier from individual “strong” La Niña (events) ever going back to the 50s.” – Nate Mantua
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Fine-scale vertical distribution and diel migrations of Pyrosoma atlanticum in the northern California Current
Abstract Blooms of the colonial pelagic tunicate Pyrosoma atlanticum in 2014–2018 followed a marine heatwave in the eastern Pacific Ocean. Pyrosome blooms could alter pelagic food webs of the northern California Current (NCC) by accelerating the biological pump via active transport, fecal pellet production and mortality events. Although aggregations of P. atlanticum have the potential to shape marine trophic dynamics via carbon export, little is known about pyrosome vertical distribution patterns. In this study, we estimated the distribution of P. atlanticum in the NCC along transects off of Oregon (45°N and 124°W) and northern California (41°N and 124°W), USA during February and July 2018. Depth-stratified plankton tows provided volume-normalized pyrosome abundance and biovolume estimates that complemented fine-scale counts by a vertically deployed camera system. Pyrosomes were numerous offshore during February, especially off Oregon. Colonies were distributed non-uniformly in the water column with peak numbers associated with vertical gradients in environmental parameters, notably density and chl-a. Vertical distributions shifted over the 24-h period, indicative of diel vertical migration. Understanding the vertical distribution of these gelatinous grazers in the NCC gives insight to their behavior and ecological role in biologically productive temperate ecosystems as conditions become more favorable for recurring blooms.
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- Award ID(s):
- 1851537
- PAR ID:
- 10364625
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Journal of Plankton Research
- Volume:
- 44
- Issue:
- 2
- ISSN:
- 0142-7873
- Format(s):
- Medium: X Size: p. 288-302
- Size(s):
- p. 288-302
- Sponsoring Org:
- National Science Foundation
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