23 research outputs found
Recommended from our members
State of the California current 2012-13: No such thing as an âaverageâ year
This report reviews the state of the California Current System (CCS) between winter 2012 and spring 2013, and includes observations from Washington State to Baja California. During 2012, large-scale climate modes indicated the CCS remained in a cool, productive phase present since 2007. The upwelling season was delayed north of 42°N, but regions to the south, especially 33° to 36°N, experienced average to above average upwelling that persisted throughout the summer. Contrary to the indication of high production suggested by the climate indices, chlorophyll observed from surveys and remote sensing was below average along much of the coast. As well, some members of the forage assemblages along the coast experienced low abundances in 2012 surveys. Specifically, the concentrations of all lifestages observed directly or from egg densities of Pacific sardine, Sardinops sagax, and northern anchovy, Engraulis mordax, were less than previous yearsâ survey estimates. However, 2013 surveys and observations indicate an increase in abundance of northern anchovy. During winter 2011/2012, the increased presence of northern copepod species off northern California was consistent with stronger southward transport. Krill and small-fraction zooplankton abundances, where examined, were generally above average. North of 42°N, salps returned to typical abundances in 2012 after greater observed concentrations in 2010 and 2011. In contrast, salp abundance off central and southern California increased after a period of southward transport during winter 2011/2012. Reproductive success of piscivorous Brandtâs cormorant, Phalacrocorax penicillatus, was reduced while planktivorous Cassinâs auklet, Ptychoramphus aleuticus was elevated. Differences between the productivity of these two seabirds may be related to the available forage assemblage observed in the surveys. California sea lion pups from San Miguel Island were undernourished resulting in a pup mortality event perhaps in response to changes in forage availability. Limited biological data were available for spring 2013, but strong winter upwelling coastwide indicated an early spring transition, with the strong upwelling persisting into early summer
The Making of a Productivity Hotspot in the Coastal Ocean
Highly productive hotspots in the ocean often occur where complex physical forcing mechanisms lead to aggregation of primary and secondary producers. Understanding how hotspots persist, however, requires combining knowledge of the spatio-temporal linkages between geomorphology, physical forcing, and biological responses with the physiological requirements and movement of top predators.) off the Baja California peninsula, Mexico.We have identified the set of conditions that lead to a persistent top predator hotspot, which increases our understanding of how highly migratory species exploit productive regions of the ocean. These results will aid in the development of spatially and environmentally explicit management strategies for marine species of conservation concern
From Sea to Sea: Canada's Three Oceans of Biodiversity
Evaluating and understanding biodiversity in marine ecosystems are both necessary and challenging for conservation. This paper compiles and summarizes current knowledge of the diversity of marine taxa in Canada's three oceans while recognizing that this compilation is incomplete and will change in the future. That Canada has the longest coastline in the world and incorporates distinctly different biogeographic provinces and ecoregions (e.g., temperate through ice-covered areas) constrains this analysis. The taxonomic groups presented here include microbes, phytoplankton, macroalgae, zooplankton, benthic infauna, fishes, and marine mammals. The minimum number of species or taxa compiled here is 15,988 for the three Canadian oceans. However, this number clearly underestimates in several ways the total number of taxa present. First, there are significant gaps in the published literature. Second, the diversity of many habitats has not been compiled for all taxonomic groups (e.g., intertidal rocky shores, deep sea), and data compilations are based on short-term, directed research programs or longer-term monitoring activities with limited spatial resolution. Third, the biodiversity of large organisms is well known, but this is not true of smaller organisms. Finally, the greatest constraint on this summary is the willingness and capacity of those who collected the data to make it available to those interested in biodiversity meta-analyses. Confirmation of identities and intercomparison of studies are also constrained by the disturbing rate of decline in the number of taxonomists and systematists specializing on marine taxa in Canada. This decline is mostly the result of retirements of current specialists and to a lack of training and employment opportunities for new ones. Considering the difficulties encountered in compiling an overview of biogeographic data and the diversity of species or taxa in Canada's three oceans, this synthesis is intended to serve as a biodiversity baseline for a new program on marine biodiversity, the Canadian Healthy Ocean Network. A major effort needs to be undertaken to establish a complete baseline of Canadian marine biodiversity of all taxonomic groups, especially if we are to understand and conserve this part of Canada's natural heritage
Recommended from our members
The state of California current, 2001 â 2002 : will the Californa current system keep its cool, or is El Niño coming?
This report summarizes physical and biological conditions in the California Current System (CCS), from Oregon to Baja California, in 2001 and 2002. The principal sources of the observations described here are the CalCOFI (California Cooperative Oceanic Fisheries Investigations), IMECOCAL (Investigaciones Mexicanas de la Corriente de California), and U.S. GLOBECLTOP (Global Ecosystems Long-term Observation Program) programs. Large-scale atmospheric and oceanic conditions in the Pacific point to a fourth consecutive La Niña-like year. This has contributed to generally stronger than normal upwelling and uncharacteristically cool waters in much of the CCS, a pattern that has persisted since late 1998. Biological productivity has been generally higher as well, particularly off Oregon. Within the observed interannual fluctuations of recent years, these conditions suggest a generally elevated production off California and Oregon, but cool conditions have led to lower than normal zooplankton biomass off Baja California. Although the tropical Pacific has exhibited some indications of a developing El Niño, it is not likely to impact the CCS during the productive upwelling season of 2002. These observations are continuing evidence that a regime shift may have occurred in 1998, resulting in substantial change in ecosystem structure in the CCS. Continued monitoring and analysis of the state of the CCS in this context is needed. We outline a plan for an integrated monitoring program for the entire region, through the creation of ACCEO (Alliance for California Current Ecosystem Observation)
Respuesta del ecosistema pelågico a la variabilidad interanual del océano frente a Baja California
Seasonal anomalies of salinity, phytoplankton chlorophyll a, and zooplankton volume off Baja California were examined from data obtained during 2001â2007. The analyses helped to identify a strong effect of physical processes on the pelagic ecosystem, diminishing near surface salinity and water column integrated phytoplankton biomass, and enhancing zooplankton volume. These changes are associated with an increase of the Pacific Decadal Oscillation (PDO) index, characterizing a warm phase of the index from summer 2002 to at least summer 2006. Negative chlorophyll a anomalies appear to respond to zooplankton grazing activity, with a possible top down effect during this period. Empirical orthogonal functions (EOFs) of Ekman drift reveal the seasonal and interannual patterns that describe the influence of upwelling zones, and there was a strong response to changes in the equatorward wind forcing from 2002 to 2006. The relationship between negative salinity anomalies and the two temporal EOF modes of Ekman drift was evident as a result of relaxation of coastal upwelling during this period. After 2006, the PDO index showed more neutral or negative values, defining the beginning of a cool phase, with positive nearsurface salinity anomalies off Baja California.
State of the California Current, Spring 2008-2009: cold conditions drive regional differences in coastal production
This report describes the state of the California Surrent system (CCS) between the springs of 2008 and 2009 based on observations taken along the west coast of North America. the dominant forcing on the CCS during this time period were La Nina type conditions that prevailed from the summer of 2007 through early 2009, transitioning to neutral El Nino-Southern Oscillation conditions in the spring of 2009. The Pacific Decadal Oscillation index was negative during this time period and its values had not returned to normal by the spring of 2009. The general effects on the California Current system were stronger than normal southward winds and upselling as well as generally colder that normal SST and shallow nitraclines; however, there were regional differences. Off Baja California sea surface temperatures did not respond to the La Nina conditions; however, concentrations of chorophyll a (Chl a) were significantly above normal, probably due to the anomolously high upwelling off Baja during most of the year. Off southern California there was no clear evidence of increased promary or secondary production, despite observations that previous La Nina conditions affected mixed layer depth, temperatures, nutrients, and nitracline depths. In both central and northern California and Oregon, stronger than normal upwelling increased primary production and prevented potential spawning of sardine north of San Francisco. In central California the midwater fish community resembled that of recent cool years, and cover by kelp was much reduced along the coast. Off Oregon there was evidence of increased abundance of boreal copepods, although the neritic boreal species did not appear to extend as far south as central California. Current predictions are for cooler conditions to change to El Nino conditions by the end of 2009; these are expected to last through the Northern Hemisphere winter of 2009-10
State of the California Current 2010-2011: Regionally Variable Responses to a Strong (But Fleeting?) La Niña
State of the California Current CalCOFI Rep., Vol. 52, 2011The state of the California current system (CCS) since spring 2010 has evolved in response to the development of cooler la NinÌa following the dissipation of the relatively weak and short-lived El NinÌo event of 2009â2010. The 2009â2010 El NinÌo appears to have dissipated quite rapidly in early spring 2010, yet the transition to anomalously cool conditions followed somewhat later with the onset of anomalously strong upwelling throughout the CCS in summer 2010 and the development of unusuallyâin some cases recordâcool conditions throughout the CCS. However, following the fairly consistent emergence of cooler la NinÌa conditions across the CCS going into summer 2010, regional contrasts were apparent. Off southern california, the effects of both the 2009â2010 El NinÌo and subsequent return to la NinÌa conditions appear to have had modest effects on the system, and the patterns that attract interest appear to be unfolding over longer time scales (e.g., freshening of upper water column and trends in nitrate and oxygen concentrations). In contrast, the northern california current has exhibited much more dramatic short-term changes over the past two years, due in part to greater variability in environmental forcing affecting this region. Ecosystem responses also varied across the CCS.the pelagic ecosystem off central and southern california showed evidence of enhanced productivity,in terms of rockfish recruitment, seabird abundance and reproductive success, etc., and the planktonic assemblage off Baja california indicated a resurgence of crustacean zooplankton following a period dominated by gelatinous zooplankton. Off northern california and oregon, however, the return to la NinÌa conditions did not entirely reverse changes in the copepod assemblage arising during the 2009â2010 El NinÌo, which may have contributed to low at-sea survival of juvenile salmon.At the time of writing, tropical conditions are ENso-neutral and forecast to remain so into fall 2011 and possibly into early 2012, yet the Pdo remained strongly negative into summer 2011. It is uncertain whether the return to cool conditions observed in the past year will continue to govern the state of the california current
Recommended from our members
The state of California, 2003 - 2004 : a rare "normal" year
This report describes the state of the California Current System (CCS)âmeteorological, physical, chemical, and biologicalâfrom January 2003 to the spring of 2004. The area covered in this report ranges from Oregon coastal waters to southern Baja California. Over the past year, most physical, chemical, and biological parameters were close to their climatological mean. Contributing to such ânormalâ conditions was the absence of a La Niña that had been expected after the previous yearâs El Niño. Noteworthy, however, are the cold and fresh anomalies in the upper 100â200 m that have been found over large areas of the CCS since 2002. Off Oregon these may have been responsible for increased productivity; off southern California these were associated with shallower nutriclines and subsurface chlorophyll maxima in the offshore areas. It is unclear if these anomalies are ephemeral or related to long-term changes in ocean climate. The effects of the hypothesized 1998 âregime shiftâ on the CCS are still difficult to discern, primarily because of other physical forcing varying on different time scales (e.g., El Niño/Southern Oscillation, ENSO, cycles; the âsubarctic influenceâ; global warming). The resolution of many of these issues requires larger scale observations than are available now. Establishment of the Pacific Coast Ocean Observing System (PaCOOS) under the guidance of NOAA will be a crucial step toward achieving that goal