ACCESS partners have been tracking ocean climate to examine seasonal patterns through the oceanographic year and assess how the ecosystem is responding to large, basin-scale climate shifts among years. Ongoing cruises started in 2004, and take place from April to October on the NOAA National Marine Sanctuary Research Vessel Fulmar. Fifty-one (51) cruises have been completed to date and 4 more cruises have been planned for 2018.
We summarize and produce an annual ‘Ocean Climate Indicators Report’ that provides information about the status and trends of physical and biological climate change indicators selected with input from 50 regional scientists and resource managers during a 2-year process led by NOAA’s National Marine Sanctuaries.
Ocean Climate Indicator Status Report: 2017
Follow this link to download our Ocean Climate Indicators Status Report for 2017 or read our synopsis below.
El Niño / Warm ocean year in 2017
Alongshore winds (strong = blue, weak = red) are responsible for driving upwelling. Winds were moderate to weak for most of 2017, with short periods of strong northerly winds. Other average to warm water years also showed weak alongshore winds (e.g. 2004-06, 2010, 2014-16), while most other years of our study period experienced strong winds in the early months.
The spring transition that marks the beginning of the upwelling season in each year occurred about 4 days later than the average transition date in 2017. Spring transition dates have varied, with earlier dates observed in most years (2006-09, 2012-13), while some of the warmer years had later transition dates (e.g. 2005, 2010, 2016).
Sea surface temperature (cold = blue, warm = red) measured by the NOAA buoy near Bodega Bay showed mostly warm temperatures in 2017, with a few periods of cooler waters. In 2004, sea surface temperatures were relatively warm but close to the long-term averages. Warm temperatures were observed in 2005-06, followed by cold surface temperatures in 2007-09. Sea surface temperatures in 2010 were warm early in the year and cold for all other months, and temperatures have remained relatively cold until mid-2014. The anomalous warm water mass known as “the blob” manifested along the central California coast in mid-2014; only in the latter half of 2016 have these warm waters started to cool.
Pacific-scale climate indices have shown great variability in ocean conditions since the start of our research in 2004. Overall, results from 2017 showed a warm ocean state. However, average PDO and NPGO values in mid- to late-2017 indicate a relatively more productive ocean state during these periods. From 2005 to 2009, PDO and NPGO were following opposite trends; a positive PDO and negative NPGO values indicated poor ocean conditions in 2005-06, while a negative PDO and positive NPGO indicated productive ocean conditions in 2007-08. Beginning in mid-2009, both PDO and NPGO have been following relatively parallel trends; a positive PDO and NPGO indicated productive ocean conditions during 2010, despite the year being deemed an El Niño year. These indices showed signs of diverging in mid-2012, but by late 2013, the indices had converged and were indicating warm conditions. In general, warm conditions have persisted in the area since late 2013.
Strong upwelling = more zooplankton
Zooplankton community composition results are not complete for 2014 and not yet available for 2015-17, but results to date illustrate the effects of improved ocean conditions on overall zooplankton abundance, with low abundances in periods of warmer ocean conditions (2004-06; late 2009; early 2010 and 2012) and increased zooplankton abundance (particularly for copepods and euphausiids [also known as krill]) in colder ocean periods (2007-08; late 2010, 2011-13). While overall zooplankton abundance was high in our preliminary results for 2014, most of this abundance is represented by gelatinous species (represented in the “Other” category), which are good indicators of a warm ocean state.
Strong upwelling = more adult krill and fatty copepods
Zooplankton communities were different between poor and productive years. Gelatinous zooplankton dominated under poor ocean conditions (2004-06; late-2009 to mid-2010; part of 2014). Northern copepod species (i.e., large, fatty copepods) reappeared in the study region starting in 2007 and tend to be found in higher abundances during colder, productive ocean conditions.
We caught mostly adult krill in Tucker trawl samples during May 2017, but smaller juvenile krill dominated samples in July and September 2017. The adult krill caught in 2017 were small, similar to the adult krill sampled in the recent warm water years of 2014-15. While 2016 was a warm water year, adult krill in this year were larger and resembled the size classes observed in cold water years (e.g. 2007-13) in our time series.
Copepod community composition results are not complete for 2014 and yet available for 2015-17. Results to date indicate a large increase in the abundance of boreal (northern) copepods during times of cold, productive ocean conditions in our region (e.g. 2007-08; spring/summer of 2009, 2011, and 2013; summer/fall of 2010; early 2014). Species common to mid-latitudes (transition zone copepods) also became more abundant in 2007, although not as dramatically; more noticeable increases were seen in 2011. Equatorial copepods (i.e., copepods from southern latitudes) increased in abundance in the September cruises of most years, likely when the equatorward California Current flow relaxed.
Average times for the Cassin’s auklet (the krill-eater)
The Cassin’s auklet, a zooplanktivorous seabird, mainly ate euphausiids (krill) in most years, including 2017. Mysids were the dominant prey in 2005-06 (poor ocean condition years), and the Cassin’s auklet experienced unprecedented breeding failure (see figure below). Increasing amounts of krill in the diet since those years has coincided with increasing productivity on the Farallon Islands since 2007. While krill comprised the majority of diet items identified in 2013 samples, most of these krill were juveniles; the prevalence of these smaller krill (which contain fewer calories than the adult krill) is thought to be the cause of a large young-of-the-year Cassin’s auklet die-off event that occurred in 2013.
Better times for the common murre (the fish-eater)
The common murre, an omnivorous seabird species, fed on juvenile rockfish and, to a lesser extent, anchovy/sardine in 2017. Common murre diet shows predominantly rockfish in the 1970s and 1980s, then mostly pelagic anchovy and sardine in the 1990s and mid-2000s. Rockfish became the dominate prey under improved ocean conditions (2008-13), although murres are now consuming more anchovy/sardine in recent warm water years. In general, poor ocean conditions correspond to a lower percentage of rockfish in the diet and reduced productivity for murres on the Farallones (see figure below), which includes 2016. Results from 2014-15 (“the blob” years) could be considered an exception to this trend.
High abundances of krill and Humpback Whales
The densities of Humpback Whales and their krill prey in 2017 were high compared to most other years in our time series. Results to date show krill in the upper 200 m of the water column varied, with higher abundances in 2004-06, 2008-11, and 2017, and lower abundances in 2007 and 2012-15. The apparent high abundance in spring 2006 is due to high abundance of highly reflective gelatinous zooplankton in the water at that time. High krill biomass was observed in 2009 and 2010, despite the later year being deemed an El Niño year.
The Humpback Whale, a main predator of krill, follows very similar patterns to the krill abundance. Years of lower krill abundance (2004-08) have corresponded to low abundance of Humpback Whales in the region. Signs of increasing Humpback Whale abundance began in late 2009, and almost five times as many whales were sighted in the summer and fall of 2010 compared to the first four years of the study. This rise in whale abundance coincided with the great krill biomass observed in 2010. Since then, Humpback Whale abundances declined through 2013, but then increased to their record high abundance in 2016.