Pamela Hidalgo

University of Concepción · Departamento de Oceanografía

Basin-scale patterns of biodiversity for zooplankton in the ocean may provide valuable insights for understanding the impact of climate change and global warming on the marine ecosystem. However, studies on this topic remain scarce or unavailable in vast regions of the world ocean, particularly in large regions where the amount and quality of avail...

The semi-permanent coastal upwelling system within the Humboldt Current System (HCS) off northern Chile provides nutrient-rich, oxygen-poor water to the euphotic zone that contributes to high levels of primary production and restricts the vertical distribution of most zooplankton species according to their tolerance to hypoxia within this highly he...

The highly productive upwelling zone in the Southeast Pacific provides inputs of C and N to the oceanic deep-water system via lateral transport, although the quality of this organic matter, the organisms being transported, and the controlling mechanisms are unclear. Here, we assessed whether the taxonomic and trophic structure of zooplankton over m...

The subtropical gyres occupy approximately 40% of the surface of the Earth and are widely recognized as oligotrophic zones. Among them, the South Pacific subtropical gyre (SPSG) shows the lowest chlorophyll-a levels (0.02–0.04 μgL–1), the deepest nutricline (>200 m) and euphotic zone (∼160 m), and the lowest rates of nitrogen fixation. The zooplank...

The subtropical gyres occupy approximately 40% of the surface of the Earth and are widely recognized as oligotrophic zones. Among them, the South Pacific subtropical gyre (SPSG) shows the lowest chlorophyll-a levels (0.02–0.04 μgL–1), the deepest nutricline (>200 m) and euphotic zone (∼160 m), and the lowest rates of nitrogen fixation. The zooplank...

Eurythenes S.I. Smith in Scudder, 1882 (Crustacea: Amphipoda) are prevalent scavengers of the benthopelagic community from bathyal to hadal depths. While a well-studied genus, molecular systematic studies have uncovered cryptic speciation and multiple undescribed lineages. Here, we apply an integrative taxonomic approach and describe the tenth spec...

The PEACETIME cruise (May–June 2017) was a basin-scale survey covering the Provencal, Algerian, Tyrrhenian, and Ionian basins during the post-spring bloom period and was dedicated to tracking the impact of Saharan dust deposition events on the Mediterranean Sea pelagic ecosystem. Two such events occurred during this period, and the cruise strategy...

The PEACETIME cruise (May–June 2017) was a basin scale study mainly dedicated to the study of different planktonic trophic regimes in the Algerian, Tyrrhenian and Ionian basins and, in particular, focusing on areas impacted by Saharan dust deposition. This paper presents the structural and functioning patterns of the zooplankton component during th...

Using detailed data of live/dead compositions, along with stage durations and molting rates, we derived, for the first time, both predatory and non-predatory mortality rates of the dominant copepod species within the Humboldt Current System and examined their relationships with environmental factors. [Please contact me for PDF]

Motivation: The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time se...

Motivation: The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time se...

Motivation: The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community led open-source database of biodiversity time se...

Motivation: The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time se...

Deoxygenation of the ocean has become a critical issue in coastal upwelling systems, which are subjected to shallow Oxygen Minimum Zones (OMZs). The OMZ can expand into the photic zone, causing hypoxic conditions and affecting pelagic organisms. During the winters 2013 and 2014, the copepod Calanus chilensis was collected off northern Chile to eval...

Calanus pacificus es una especie copépoda que juega un rol esencial en el ecosistema de la corriente de California‚ una zona altamente vulnerable ante la acidificación del océano (AO) debido a múltiples factores regionales tanto naturales como antropogénicas‚ que potencializan la acidez oceánica actual. Aún así‚ los efectos del incremento del pCO2...

In the Humboldt Current System (HCS) off northern Chile (23° S), 6 samplings were conducted in 2013 and 2014, each at 8 depths ranging from 5 to 80 m, to study the role of environmental variability on the abundance and vertical distribution of the eggs of dominant copepods, with special emphasis on hypoxia associated with the oxygen minimum zone (O...

One hundred and five juveniles and adults of Euphausia mucronata were incubated in order to estimate their daily growth rates (DGR) using the standard instantaneous growth rate method. From 77 krill that survived after 2 days of incubation under laboratory conditions, 70 individuals molted (35.1% males, 64.9% females). E. mucronata mean intermolt p...

Neomormonilla minor (Giesbrecht, 1891) is a small planktonic copepod distributed widely in intermediate and deep waters of the ocean, mainly at depths of 400-1000 m. The species was reported earlier only for the tropical Pacific Ocean (Central America, Galapagos Islands, and north of Peru). The present study provides the first record of females of...

Copepods are major components of zooplankton in the Humboldt Current system. Here, intra-seasonal (monthly) variation of upwelling and its influence on the copepod community were assessed. Species abundances, species richness, diversity (Shannon–Wiener index) and dominance, were studied during four upwelling periods (2002–2009) at the Station 18 ti...

Zooplankton production is a critical issue for understanding marine ecosystem structure and dynamics, however, its time-space variations are mostly unknown in most systems. In this study, estimates of copepod growth and production (CP) in the coastal upwelling and coastal transition zones off central-southern Chile (∼35–37° S) were obtained from an...

Community structure of pelagic copepods inhabiting the coastal upwelling zone of central-southern Chile was compared between the periods 2002-2004 and 2010-2012. For both periods, 74 copepod species were identified; the Order Calanoida accounted for 68% of the total abundance. Numerically dominant species (ca. 80% of total abundance) were Paracalan...

Egg production (EP) and egg development rate (DR) of Centropages brachiatus, Calanus chilensis and Paracalanus indicus, three abundant copepods in the Humboldt Current System, were experimentally assessed during spring-summer and autumn-winter periods between 2001 and 2012 in northern Chile (23 degrees S) and central/southern Chile (36 degrees S)....

Morphological changes in the exoskeleton of naupliar stages 2-6 and copepodid stages I-V of Rhincalanus nasutus are described. On the distal segment of naupliar antennule, one lateral seta and two medial setae are added during each molt to nauplius 3-6. A naupliar arthrite is a thick, distinctive structure on the coxa of antenna, and the exopod of...

The in situ natural mortality (predation excluded) and growth rates (g) of the pelagic copepod Paracalanus indicus were studied under variable upwelling regimes and upon presence of the oxygen minimum zone (OMZ) in two upwelling sites off Chile, Mejillones (~23°S) and Concepción (~36°S). Partial mortality was estimated using neutral red staining to...

The in situ natural mortality (predation excluded) and growth rates (g) of the pelagic copepod Paracalanus indicus were studied under variable upwelling regimes and upon presence of the oxygen minimum zone (OMZ) in two upwelling sites off Chile, Mejillones (~23°S) and Concepción (~36°S). Partial mortality was estimated using neutral red staining to...

Two zooplankton time series from the coastal upwelling region off Chile were studied in terms of copepod biomass and abundance in relation with upwelling variation. The time series from Antofagasta (23°S) was collected between 1988 and 2008 and based on bi-annual sampling, whereas the time series from Concepción (36°S) was based on monthly samples...

a b s t r a c t This study assessed the structure of the copepod community in the upper 200 m of the coastal upwelling region off central-southern Chile in late summer 2009. Vertically stratified zooplankton samples and hydrographic variables were obtained from 42 stations over the continental shelf and oceanic areas. The survey took place during a...

The copepod community structure from the Northern and Central/southern upwelling regions off Chile was studied and compared. The derived community descriptors were species abundance (N), species richness (R) and the Shannon-Wiener diversity index (H′). These descriptors were related to distinct habitats and conditions, sea surface temperature (SST)...

A new series of intermolecular hydrogen-bonded complexes has been obtained using mesogenic 4-n-nonyloxybenzoic acid and mesogenic 5-(4-pyridyl)-2-(4-n-alkoxy) benzylideneamino-1,3,4-thiadiazole moieties. The thermal and phase behaviour of these complexes were studied by thermal microscopy and differential scanning calorimetry. Intermolecular hydrog...

In the Humboldt Current System, the region off central-southern Chile has relatively high eddy kinetic energy, generating an extensive coastal transition zone (∼600 km offshore) in which coastally derived eddies are recurrent features. This energy might promote strong exchanges of water, biogeochemical properties, and plankton between the coastal u...

Automated image analysis was used to assess changes in the mesozooplankton community structure from the coastal upwelling zone off Central/southern Chile at Station 18 (36°S). Nearly monthly samples from August 2002 to December 2005 were processed to obtain zooplankton size spectra in the size range of 0.25–30.25 mm and taxa classification. The slo...

Zooplankton in the coastal upwelling region off northern Chile may play a significant biogeochemical role by promoting carbon flux into the subsurface OMZ (oxygen minimum zone). This work identifies the dominant zooplankton species inhabiting the area influenced by the OMZ in March 2000 off Iquique (20°S, northern Chile). Abundance and vertical dis...

Marine pelagic copepods must cope with a highly heterogeneous environment in coastal upwelling systems. In addition to spatial and temporal heterogeneity in temperature and food supply, advective forces may strongly influence their populations. Off northern Chile, the population of Calanus chilensis, a dominant copepod associated with upwelling cen...

A time series study of the copepods Calanus chilensis and Centropages brachiatus was carried out at the coastal upwelling zone of Mejillones (23°S, northern Chile), to analyze their annual life cycles in association with upwelling variation. These species co-exist in the upwelling zone. Weekly sampling of zooplankton and oceanographic variables inc...

Variations of egg production rate (EPR), hatching success (HS), production of abnormal larvae (AL) and histology of gonads have been investigated with Calanus chilensis females sampled weekly, from late November to December 2004, at a station located in the coastal zone off Dichato (Chile), at time diatom concentration in phytoplankton bloom was hi...

Zooplankton sampling at Station 18 off Concepción (36°30′S and 73°07′W), on an average frequency of 30 days (August 2002 to December 2005), allowed the assessment of seasonal and inter-annual variation in zooplankton biomass, its C and N content, and the community structure in relation to upwelling variability. Copepods contributed 79% of the total...

A time series of zooplankton sampling carried out at Station 18 off Concepción (36°S, 73°W) from August 2002 to December 2003 allowed the study of annual life cycles of the copepods Calanus chilensis and Centropages brachiatus in association with environmental variability in the coastal upwelling zone. Changes in the abundance of eggs, nauplii, and...

The synthesis and liquid crystalline properties of new series of 1,2,4‐ and 1,3,4‐oxadiazole derivatives (2a–f and 5a–f respectively) are reported. These compounds contain only one terminal flexible alkoxy chain, the other terminal substituent is a protecting benzyl group. All compounds of series 2 exhibit an enantiotropic nematic phase. The homolo...

New chiral Schiff bases with a 1,3,4‐thiadiazole unit in the rigid core were synthesized (SB1–SB4). These compounds contain a chiral chain derived from (S)‐isoleucine and (R)‐2‐octanol. Their liquid crystalline properties were studied by polarizing optical microscopy, differential scanning calorimetry and X‐ray diffraction. Thereby it was found tha...

Eucalanus inermis Giesbrecht, 1893 is an abundant species of the Humboldt Current and recognized as one of the large-sized herbivorous copepods in the pelagic realm of the eastern South Pacific. However, lack of information on morphological and taxonomic characters of early stages of this species is a major shortcoming to identify them from field s...

The synthesis and liquid crystalline properties of a new series of diacylhydrazine derivatives (2a–g) are reported. All compounds of series 2 exhibit a smectic C (SmC) phase. The first homologues (2a, 2b) display a monotropic SmC mesophase, whereas the highest homologues (2c–g) exhibit an enantiotropic SmC phase. The liquid crystalline properties w...

The vertical and ontogenetic distribution, and diel vertical migration (DVM), of Eucalanus inermis in relation to the strong vertical gradient in oxygen concentration associated with an intense oxygen minimum zone (OMZ) were studied at a coastal area off northern Chile (20–21° S). A close relationship between the abundance of the whole copepod popu...

Supramolecular liquid crystalline complexes were obtained from binary mixtures of 3‐(4‐pyridyl)‐5‐(4‐n‐alkoxy)phenyl‐1,2,4‐oxadiazoles and 2,5‐thiophene dicarboxylic acid. Although the oxadiazole derivatives and the dicarboxylic acid are non‐mesomorphic, the H‐bonded complexes exhibit mesomorphism. Their liquid crystalline properties were investiga...

Eucalanus inermis is an abundant species in the eastern tropical and subtropical South Pacific, including the oceanic and coastal waters off Chile and Peru. Its annual life cycle was studied through a time-series sampling (weekly intervals) during 2002, at a fixed coastal station at an upwelling site (Mejillones Bay, 23S) off northern Chile. The mo...

Euphausiids are abundant, although little studied components of the zooplancton in the Humboldt Current ecosystem. For instance, the effect that large scale ocean variability may exert on their population dynamics, abundance and distribution is unknown. In this work, based on 2-year time series data and two spatial surveys on December 1996 and July...

Euphausiids are abundant, although little studied components of the zooplancton in the Humboldt Current ecosystem. For instance, the effect that large scale ocean variability may exert on their population dynamics, abundance and distribution is unknown. In this work, based on 2-year time series data and two spatial surveys on December 1996 and July...

The synthesis and liquid crystalline properties of new Schiff 's bases (series 3a-f) and azo compounds (4a-f) incorporating pyridine and 1,3,4-thiadiazole rings are reported. The first homologues in the series of Schiff's bases (3a-c) show a monotropic mesophase and the homologues 3d-f display an enantiotropic SmA phase. The only azo compounds to e...

We report on direct current measurements on a nearshore location, Peninsula Mejillones, within the Humboldt current system (HCS) in the Eastern South Pacific. Currents and hydrography were measured in a 23-station grid on three surveys (October 1998; January and October 1999). We show that the nearshore environment of the HCS is dominated by a pole...

Se estudió la circulación de la bahía de Antofagasta (23° S) sobre las base de mediciones de series de tiempo de corrientes en verano e invierno de 1999, de un crucero oceanográfico realizado en agosto de 1999 y una serie de 9 meses de perfiles de corrientes a intervalos de 15 días. La información de corrientes sumada a datos de temperatura, salini...

A 2-year time series (17-d interval) of zooplankton, sampled from June 1996 through January 1998, along with oceanographic data, allowed the study of species abundances and diversity during non-El Nio and El Nio conditions at Mejillones (23 S), northern Chile. A total of 28 species was identified, of which the most abundant were the calanoids Parac...

A field experiment was carried out in October 1998 during active upwelling in a coastal area off the Mejillones Peninsula (23 S). Zooplankton was sampled at day and night, during two subsequent days at 4 stations inside and outside of the upwelling plume. Three depth strata were sampled: 0–20 m, 20–80 m and 80–200 m. Oceanographic data were obtaine...

Circulation of Bahía de Antofagasta (23°S) was studied based on time series measurements of currents in summer and winter 1999, an oceanographic survey performed in August 1999, and a 9-months series of current profiling at 15 d time intervals. Current data, along with information on temperature, salinity, oxygen, and wind data, allowed the analysi...

From a time-series of sea surface temperature (SST) and zooplankton data from December 1991 through January 1998, and using a temperature-dependent model, we studied the growth rate (g), female size, generation time (GT), and number of generations per year of Calanus chilensis from the Mejillones Peninsula, northern Chile. Female size was negativel...

During the austral spring (December 1996), numerical abundance of copepod species (Crustacea: Copepoda) was estimated from 53 sampling stations scattered over the coastal waters off Mejillones Peninsula, northern Chile. Samples were obtained from two depth strata; 0-50 m and 50-200 m depth. Oceanographic data over the three-day cruise indicated tha...