State of the California current 2012-13: No such thing as an “average” 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 years’ 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 Brandt’s cormorant, Phalacrocorax penicillatus, was reduced while planktivorous Cassin’s 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

Questioning the rise of gelatinous zooplankton in the World's oceans

During the past several decades, high numbers of gelatinous zooplankton species have been reported in many estuarine and coastal ecosystems. Coupled with media-driven public perception, a paradigm has evolved in which the global ocean ecosystems are thought to be heading toward being dominated by “nuisance” jellyfish. We question this current paradigm by presenting a broad overview of gelatinous zooplankton in a historicalcontext to develop the hypothesis that population changes reflect the human-mediated alteration of global ocean ecosystems. To this end, we synthesize information related to the evolutionary context of contemporary gelatinous zooplankton blooms, the human frame of reference forchanges in gelatinous zooplankton populations, and whether sufficient data are available to have established the paradigm. We conclude that the current paradigm in which it is believed that there has been a global increase in gelatinous zooplankton is unsubstantiated, and we develop a strategy for addressing the critical questions about long-term, human-related changes in the sea as they relate to gelatinous zooplankton blooms

Changes in the copepod community during the 1992–93 enso at san lorenzo channel, gulf of california

"Se describe la estructura de la comunidad de copépodos presente en el Canal de San Lorenzo, Golfo de California, durante 1990 y el ENSO 1992–93. Entre estos periodos de recolección, la principal diferencia fue la disminución del calanoide Nannocalanus minor. Esta especie oceánica, distribuida principalmente en la zona ecuatorial, fue una de las dominantes en el plancton del canal de febrero a agosto de 1990. Durante el ENSO 1992–93, parece haber sido parcialmente desplazada por otra especie ecuatorial de tamaño más pequeño, Clausocalanus arcuicornis, y por la especie tropical costera Undinula vulgaris. Entre los carnívoros, Euchaeta marina disminuyó durante el ENSO, mientras que se observó la incidencia de Candacia truncata y Candacia catula. El tamaño de malla de la red recolectora influyó sensiblemente en la composición específica de la comunidad observada. Se capturó un 30% más de especies con una malla de 300 µm que con una de 500 µm y las abundancias de las especies de menor talla presentaron altos porcentajes de escape en esta última.""The structure of the copepod community from the San Lorenzo Channel, Gulf of California, is described for 1990 and the 1992–93 ENSO. The main difference between sampling periods was the decrease of the calanoid Nannocalanus minor. This oceanic species, distributed mainly in the equatorial zone, was one of the dominant in the plankton of the channel from February to August 1990. During the 1992–93 ENSO it appeared to be partially displaced by another equatorial but smaller species, Clausocalanus arcuicornis, and the tropical coastal species, Undinula vulgaris. Among the carnivores, Euchaeta marina decreased during ENSO, while the incidence of Candacia truncata and Candacia catula was observed. The mesh size of the net used noticeably affected the community structure observed, due to the escape of organisms through the net. With the net of 300 µm mesh size, 30% more species were collected than with the net of 500 µm, and the abundances of the smaller species presented high escape percentages with the latter.

Seasonal variability of copepods and cladocerans in Bahía de los Ángeles (Gulf of California) and importance of Acartia clausi as food for whale sharks

"Bahía de los Ángeles se localiza en la costa baja californiana del golfo de California, adyacente al Canal de Ballenas. La bahía recibe de éste una influencia dinámica de la marea y al mismo tiempo está protegida por numerosas islas. Es una bahía muy productiva y alberga una alta diversidad de especies, algunas de ellas protegidas como el tiburón ballena (Rhincodon typus). Este estudio describe la variación estacional de los grandes taxones de zooplancton y especies de copépodos y cladóceros entre mayo de 2003 y octubre de 2004. Los copépodos fueron dominantes durante el invierno y la primavera (83–99% de la abundancia del zooplancton), y experimentaron un dramático descenso en el otoño de 2003 (37–66%) y el verano de 2004 (25–45%). Los cladóceros fueron el segundo grupo más abundante, representado por Pseudevadne tergestina y Penilia avirostris. La primera especie se presentó todo el año con abundancia baja en invierno, mientras que la segunda se presentó sólo en verano y otoño. Otros taxones del holozooplancton contribuyeron con menos del 15% de la abundancia en la mayoría de las muestras, mientras que el merozooplancton con menos del 8%. No obstante, tanto en octubre de 2003 como de 2004 hubo una abundancia notable de equinodermos y otras larvas que contrasta con su escasez en otras temporadas. En el invierno de 2004 dominaron especies de copépodos templado–subtropicales como Calanus pacificus y Acartia tonsa. La alta abundancia de copépodos durante la primavera obedeció a Acartia clausi (mediana = 28,034 ind m–3). Sin embargo, la abundancia máxima de zooplancton (40,468 ind m–3, 99.5% copépodos) provino de una muestra recolectada al sur de punta Arena, donde se avistaron dos tiburones ballena alimentándose. El cambio en composición de especies durante el verano coincidió con la predominancia de los vientos del este, descritos en la literatura, que inducen una reversión en la circulación y un probable acarreo de especies tropicales (Centropages furcatus, Subeucalanus subcrassus, Acrocalanus longicornis, Temora discaudata, y Corycaeus amazonicus) al interior de la bahía durante el verano y el otoño.""Bahía de los Ángeles is located on the Baja Californian coast of the Gulf of California, adjacent to Ballenas Channel. The bay receives a dynamic tidal influence from the channel but is protected by numerous islands. It is a highly productive bay that harbors a high diversity of species, some of them protected such as the whale shark (Rhincodon typus). This study describes the seasonal variability of major zooplankton taxa and copepod and cladoceran species between May 2003 and October 2004. Copepods were dominant during winter and spring (83–99% of the zooplankton abundance), experiencing a dramatic decrease in autumn 2003 (37–66%) and summer 2004 (25–45%). Cladocerans were the second most abundant group, represented by Pseudevadne tergestina and Penilia avirostris. The former species occurred year–round with low abundance in winter, whereas the latter occurred only in summer and autumn. Other holozooplankton taxa contributed with less than 15% of the abundance in most of the samples, while merozooplankton contributed less than 8%, though in October of 2003 and 2004 there was a remarkable abundance of echinoderms and other larvae contrasting with their shortage in other seasons. In winter 2004, temperate–subtropical copepod species dominated, such as Calanus pacificus and Acartia tonsa. The high abundance of copepods during spring obeyed to Acartia clausi (median = 28,034 ind m–3); however, the maximal zooplankton abundance (40,468 ind m–3, 99.5% copepods) came from a sample collected south of Punta Arena, where two whale sharks were observed foraging. The shift in species composition during summer coincides with the predominance of easterly winds described in the literature inducing a reversed circulation and a probable transport of tropical species into the bay during summer and autumn (Centropages furcatus, Subeucalanus subcrassus, Acrocalanus longicornis, Temora discaudata, and Corycaeus amazonicus).

Claves para la gestión de empresas en territorio comunal

Tesis de MaestríaSobrevivir, emigrar, emprender… cualquier elección es compleja, cualquier camino imperfecto. Muchos estamos sobreviviendo. Hay quienes, además, emigramos para sobrevivir. Algunos nos mantenemos con lo poco que hay a la mano y otros emigramos para emprender de manera individual. Lo que aquí se trata es este dilema desde una visión colectiva, desde un territorio comunal

Calcareous phytoplankton response to the half century of interannual climatic variability in Santa Barbara Basin (California)

A high-resolution study of calcareous phytoplankton in a box core from the Santa Barbara Basin (SBB) reveals floral assemblage fluctuations which can be related to climatic and paleoceanographic changes during the last half century (1940-1996). In particular, Gephyrocapsa oceanica production increased during El Niño periods, in response to high temperatures, silica depletion, and increased iron availability. Conversely, Helicosphaera carteri flux increases in conjunction with lower surface temperatures associated with La Niña episodes. Increasing abundances of Florisphaera profunda and Umbilicosphaera sibogae after 1970 reflect a warming trend and increased stratification within the basin associated with the warm phase of the Pacific Decadal Oscillation (PDO). Conversely, increased abundances of Coccolithus pelagicus and Calcidiscus leptoporus before 1970 mark the cold phase of PDO. These coccolithophore production rate data are consistent with instrumental records of surface and thermocline temperatures monitored since 1950. This is the first study to document the response of calcareous phytoplankton to surface water warming occurring in SBB since 197

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

Shifts between gelatinous and crustacean plankton in a coastal upwellin region

proyectos RADIALES (IEO) y EURO-BASIN (Ref. 264933, 7FP)Variability in the dominance of copepods vs. gelatinous plankton was analysed using monthly time-series covering the last 55 years and related to changes in climatic, oceanographic, and fishery conditions in the upwelling region of Galicia (NW Spain). Seasonality was generally the main component of variability in all groups, both along the coast and in the nearby ocean, but no common long-term trend was found. Coastal copepods increased since the early 1990s, and gelatinous plankton increased in the ocean during the 1980s. Different trends were found for gelatinous plankton in two coastal sites, characterized by increases in either medusae or tunicates. In all series, multiyear periods of relative dominance of gelatinous vs. copepod plankton were evident. In general, copepod periods were observed in positive phases of the main modes of regional climatic variability. Conversely, gelatinous periods occurred during negative climatic phases. However, the low correlations between gelatinous plankton and climatic, oceanographic, or fishery variables suggest that local factors play a major role in their proliferations.7FP, IEOPreprin

Salp contributions to vertical carbon flux in the Sargasso Sea

We developed a one-dimensional model to estimate salp contributions to vertical carbon flux at the Bermuda Atlantic Time-series Study (BATS) site in the North Atlantic subtropical gyre for a 17-yr period (April 1994 to December 2011). We based the model parameters on published rates of salp physiology and experimentally determined sinking and decomposition rates of salp carcasses. Salp grazing was low during non-bloom conditions, but routinely exceeded 100% of chlorophyll standing stock and primary production during blooms. Fecal pellet production was the largest source of salp carbon flux (78% of total), followed by respiration below 200 m (19%), sinking of carcasses (3%), and DOC excretion below 200 m (\u3c 0.1%). Thalia democratica, Salpa fusiformis, Salpa aspera, Wheelia cylindrica, and Iasis zonaria were the five highest contributors, accounting for 95% of total salp-mediated carbon flux. Seasonally, salp flux was higher during spring-summer than fall-winter, due to seasonal changes in species composition and abundance. Salp carbon export to 200 m was on average 2.3 mg C m(-2) d(-1) across the entire time series. This is equivalent to 11% of the mean 200 m POC flux measured by sediment traps in the region. During years with significant salp blooms, however, annually-averaged salp carbon export was the equivalent of up to 60% of trap POC flux at 200 m. Salp carbon flux attenuated slowly, and at 3200 m the average modeled carbon from salps was 109% of the POC flux measured in sediment traps at that depth. Migratory and carcass carbon export pathways should also be considered (alongside fecal pellet flux) as facilitating carbon export to sequestration depths in future studies. Published by Elsevier Ltd