We analyze for the first time the spatial distribution of siphonophores in relation to water mass... more We analyze for the first time the spatial distribution of siphonophores in relation to water masses along a 3750-km oceanic transect between the Chilean coast and the Easter Island (278 S), a sector scarcely known of eastern South Pacific Ocean. Thirty-one siphonophore species were identified; Sulculeolaria turgida and Vogtia glabra were recorded for the first time in this sector. The most abundant species were Muggiaea atlantica (29.2%), Eudoxoides spiralis (24.5%) and Lensia subtilis (13.1%). Two different siphonophore assemblages east and west of 76 W, associated respectively with Subantarctic Water and Subtropical Water masses, can be used as water mass indicators. The former included the three most abundant species, whereas the latter showed greater species richness. This study provides basic knowledge on spatial distribution of siphonophores, which is important to develop future research focused on understanding the ecological role and biological processes driven by planktonic organisms in the southeastern Pacific Ocean.
This work provides a first taxonomic description of appendicularians collected during September a... more This work provides a first taxonomic description of appendicularians collected during September and August of 1995 in the north coast of Chile (18º23'-31º00' S). Fifteen species were identified. They belong to the families Oikopleuridae (Oikopleura longicauda, O. cophocerca, O. dioica, O. rufescens, O. fusiformis, O. albicans, O. gracilis and Megalocercus abyssorum), and Fritillariidae (Fritillaria pellucida typica, F. pellucida omani, F. haplostoma F. tenella, F. formica digitata, F. venusta and F. fraudax). All the species are first records for waters of northern Chile, thus broadening their previous distribution in the southeast Pacific. The most abundant species were Oikopleura longicauda (56.1 %), O. gracilis (10.4 %), Fritillaria pellucida typica (6.7 %); O. albicans (5.0 %); F. pellucida omani (4.7 %); O. cophocerca (4.4 %) and F. venusta (4.1 %), whereas the eight remaining species, constituted 8.6 % of the total appendicularians collected.
The macrozooplancton composition and distribution in the Magellan fjords were analyzed in October... more The macrozooplancton composition and distribution in the Magellan fjords were analyzed in October 1998. Samples were collected from 200 m depth to the surface using a Bongo net (200 mesh size). The area of study was characterized by its low specific diversity. Four chaetognath species, five euphausiids and seven siphonophores were identified. The dominant species were, Sagitta tasmanica, Euphausia vallentini and Muggiaea atlantica and their highest abundance’s were observed in the innermost stations, mainly inside the Otway, Almirantazgo and Agostini Sounds. The zooplanktonic biomass was low, with a mean of 85.28 ml/1.000 m 3 . High relative values were observed in the Almirantazgo and Agostini Sounds, and in the southern part of the Beagle Channel.
This study identifies the abundance and spatial distribution of siphonophores collected during sp... more This study identifies the abundance and spatial distribution of siphonophores collected during spring of 2011 between the Reloncaví Fjord and the Boca del Guafo Passage, in the Chiloé Inland Sea (CIS), Chile. Nine species of siphonophore were identified (three Physonectae and six Calycophorae), of which Agalma elegans, Cordagalma ordinatum and Lensia meteori were recorded for the first time in the waters of the CIS. The dominant species were Muggiaea atlantica (88.0%) and Lensia conoidea (9.5%). The highest occurrence frequency was recorded for M. atlantica (81.2%) and L. conoidea (62.5%). Eudoxids were collected only for M. atlantica (52.1%), L. conoidea (43.7%) and Dimophyes arctica (4.2%). The highest siphonophore densities were found in the northern microbasin (Reloncaví Fjord, Reloncaví and Ancud gulfs), an area characterised by a predominance of estuarine waters (greater vertical stratification, lower temperatures and salinity, and a higher concentration of dissolved oxygen). The vertical distribution patterns showed that M. atlantica is found throughout the water column in the northern microbasin, though with preference for the depths of 0-50 m. In the southern microbasin it was distributed mainly in deeper waters (>50 m). L. conoidea tends to avoid the surface estuarine layer (0-25 m) and is mainly distributed through deeper layers (>25 m). The association with environmental variables shows that temperature and dissolved oxygen have a significantly influence over dominant species. Siphonophorae community showed unimodal responses to the environmental gradients and high interspecific variability compared with previous campaigns in the same geographical area.
We have compiled available records in the literature for medusozoan cnidarians and ctenophores of... more We have compiled available records in the literature for medusozoan cnidarians and ctenophores of South America. New records of species are also included. Each entry (i.e., identified species or still as yet not determined species referred to as “sp.” in the literature) includes a synonymy list for South America, taxonomical remarks, notes on habit, and information on geographical occurrence. We have listed 800 unique determined species, in 958 morphotype entries: 5 cubozoans, 905 hydrozoans, 25 scyphozoans, 3 staurozoans, and 20 ctenophores. Concerning nomenclatural and taxonomical decisions, two authors of this census (Miranda, T.P. & Marques, A.C.) propose Podocoryna quitus as a nomen novum for the junior homonym Hydractinia reticulata (Fraser, 1938a); Euphysa monotentaculata Zamponi, 1983b as a new junior synonym of Euphysa aurata Forbes, 1848; and Plumularia spiralis Milstein, 1976 as a new junior synonym of Plumularia setacea (Linnaeus, 1758). Finally, we also reassign Plumula...
Beroe gracilis Künne, 1939 is a small neritic ctenophore, previously recorded only from cold wate... more Beroe gracilis Künne, 1939 is a small neritic ctenophore, previously recorded only from cold waters of the northern hemisphere. The present study provides the first record of the species in the southern hemisphere, found in the surface layer of the Humboldt Current System off the central Chilean coast (32°-36.5° S). A complete description of this material is provided.
ABSTRACT. Seamounts are vulnerable marine ecosystems. In Chile, information on these ecosystems i... more ABSTRACT. Seamounts are vulnerable marine ecosystems. In Chile, information on these ecosystems is quite scarce; thus, a compilation of information on their geographical distribution and biodiversity is presented herein. A total of 118 seamounts distributed in the Chilean EEZ are identified and characterized. Additionally, an in situ assessment was carried out on the Juan Fernandez seamounts 1 and 2 (JF1 and JF2), which were also oceanographically characterized. Phytoplankton, zooplankton, and marine invertebrate samples were collected and an exploratory fishing survey was executed using different gears. According to the bibliographical review, a total of 82 species have been collected on the JF1 and JF2 seamounts, highlighting findings of black coral species caught in lobster traps at the Juan Fernandez Archipelago. Submarine images of the marine substrate at JF1 and JF2 reveal characteristics attributable to the impact of bottom dredges, coinciding with the informa-tion obtained f...
<i>Nemopsis mianzani</i> n. sp. (Figure 1–2; Table 1) <b>Material examined.<... more <i>Nemopsis mianzani</i> n. sp. (Figure 1–2; Table 1) <b>Material examined.</b> Holotype: Male medusa with 9.5 mm in length. 11.xi. 2013. Off Dichato, Chile (36 ° 30 'S, 73 °05'W) (MNHNCL/CNID- 15001); Paratypes: Two female medusa with 9.3 and 8.9 mm in length. 11.xi. 2013. Off Dichato, Chile (36 ° 30 'S, 73 °05'W) (ZOOTIMO 201404). Length of umbrella, from top to edge 9.48 mm Diameter or umbrella at the top of the gastric cavity 7.53 mm Diameter or umbrella at the edge 7.48 mm Length of subumbrella 5.69 mm Diameter or subumbrella at the edge 6.62 mm Width of velum 480–546 μm Diameter of gastric cavity 3.24 mm Length of gastric cavity, from top to the edge of manubrium 2.59 mm Diameter of manubrium 1.08 mm Length of oral tentacles up to 1.49 mm Diameter of oral tentacles at the base 171–183 μm Number of oral tentacle ramifications up to 7 Diameter of nematocyst aggregations at the oral tentacles extremities up to 47 μm Distance between radial canals 2.61 mm Diameter of radial canal 193–208 μm Tentacular bulb length up to 3.06 mm Number of filiform tentacles per bulb 26–30 Diameter of filiform tentacles tentacles at the base 80–95 μm Diameter of club-shaped tentacles at the base 109 μm Length of the club-shaped tentacles up to 1.36 mm Diameter of the club-shaped tentacle ocellum 30 μm Diameter of the filiform tentacle ocellum 72–79 μm <b>Description.</b> Medusa. Umbrella bell-shaped, transparent, about 1.5 times higher than wide, with top and sides curved. Thick apical jelly, about 2 / 5 of bell-height. Four interradial subumbrellar pockets projecting into apical jelly. Four radial canals connected to a thin ring canal near broad marginal bulbs. Bulbs curved with 23-29 filiform tentacles. In some bulbs, a pair of short club-shaped tentacles is present in the median portion, inserted above the filiform tentacles. Ocelli at the base of each filiform tentacle, and on a swelling near the base in club-shaped tentacles. Manubrium conical, ending in a mouth with four short lips. Base of manubrium with perradial lobes res [...]
We analyze for the first time the spatial distribution of siphonophores in relation to water mass... more We analyze for the first time the spatial distribution of siphonophores in relation to water masses along a 3750-km oceanic transect between the Chilean coast and the Easter Island (27° S), a sector scarcely known of eastern South Pacific Ocean. Thirty-one siphonophore species ...
Blooms of stinging pelagic cnidarians have been causing increasing health problems for humans wor... more Blooms of stinging pelagic cnidarians have been causing increasing health problems for humans worldwide. Physalia physalis is among the worst stinging species in the Atlantic and Pacific oceans along the North and South American coasts. This siphonophore species has a large gas float and lives at the ocean surface, where its distribution is affected mainly by winds. P. physalis's strandings were observed in the southeastern Pacific Ocean for three consecutive years (2014 to 2016). Data of stranded P. physalis were gathered daily through a collaborative effort between the Chilean Navy and the Chilean Ministry of Health. The association between oceanographic variables and the stranded P. physalis was assessed using a generalized additive mixed model (GAMM) and cross-correlation analysis. The largest stranding occurred along more than 2600 km of coastline and totaled 44,683 colonies. Most of the strandings were along the central and south-central coast of Chile, where almost 200 pe...
Journal of the Marine Biological Association of the United Kingdom, 2016
This study characterizes the abundance and spatial distribution of siphonophores between the Trin... more This study characterizes the abundance and spatial distribution of siphonophores between the Trinidad Channel (50°06′S) and the Strait of Magellan (52°45′S) in southern Chile, during October–November 2009. Ten species were identified, of which Agalma elegans, Rosacea plicata and Sphaeronectes fragilis are new records for this region. Dominant species showed similar dominance values e.g. Lensia conoidea (26.3%), Dimophyes arctica (24.6%), Lensia meteori (22.2%) and Muggiaea atlantica (20.7%). Eudoxids of L. conoidea and D. arctica represented 97.3% of all eudoxids collected and they were mainly collected in estuarine waters. The highest densities were found in estuarine waters (high vertical stratification and low temperature, salinity and dissolved oxygen values). On the other hand, the lowest densities were found in coastal areas influenced by permanent influx of Sub-Antarctic waters from the Pacific (greater instability and vertical mixing, higher temperatures, salinity and dissol...
La clase Thaliacea, conformada por salpas, doliólidos y pyrosomas, son organismos filtradores hol... more La clase Thaliacea, conformada por salpas, doliólidos y pyrosomas, son organismos filtradores holoplanctónicos, frecuentemente son uno de los mayores componentes de la biomasa zooplanctónica en la capa superficial más cálida y templada de los océanos (Blackburn, 1979). Los doliólidos, son el grupo menos estudiado de la clase Thaliacea, a pesar que sus primeros registros datan de 1835, cuando Quoy y Gaimard se refirieron al género Doliolum en su reporte sobre la Expedición "Astrolabe" (1826-1829) al Pacífico tropical. El estudio de estos tunicados se intensificó en la segunda mitad del siglo XX, cuando los científicos comenzaron a comprender el complejo ciclo de vida de estos organismos (Esnal & Daponte, 1999).
We determined the distribution and abundance of pelagic copepods in the eastern equatorial Pacifi... more We determined the distribution and abundance of pelagic copepods in the eastern equatorial Pacific between the coast of Ecuador and the Galapagos Islands under oceanographic conditions associated with the weak La Niña event of 2001. In September-October 2001, negative anomalies of sea surface temperature from this event still remained in the eastern equatorial Pacific, mainly between Ecuador and the Galapagos Islands. The event allowed the incursion of the Humboldt Current farther north and of the Equatorial Undercurrent into the study area, favouring a strong Equatorial Front and upwelling processes. There was evidence of mesoscale eddies in the study area and of the presence of the South Equatorial Current going westward at about 1°N. We identified 107 copepod species and analyzed the distribution of the 10 most abundant ones: Oncaea venusta, Subeucalanus pileatus, S. crassus, S. subtenuis, Paraeucalanus attenuatus, Pleuromamma borealis, Scolecithrix danae, Clausocalanus farrani, Temora discaudata and Calanus chilensis. Copepod distribution and abundance exhibited marked latitudinal differences related to the oceanographic conditions; abundance was highest to the southeast of the Galapagos Islands. Oncaea venusta, Pleuromamma borealis, Calanus chilensis, and Subeucalanus subtenuis were the species that best defined the Equatorial Front and the upwelling process.
We analyze for the first time the spatial distribution of siphonophores in relation to water mass... more We analyze for the first time the spatial distribution of siphonophores in relation to water masses along a 3750-km oceanic transect between the Chilean coast and the Easter Island (278 S), a sector scarcely known of eastern South Pacific Ocean. Thirty-one siphonophore species were identified; Sulculeolaria turgida and Vogtia glabra were recorded for the first time in this sector. The most abundant species were Muggiaea atlantica (29.2%), Eudoxoides spiralis (24.5%) and Lensia subtilis (13.1%). Two different siphonophore assemblages east and west of 76 W, associated respectively with Subantarctic Water and Subtropical Water masses, can be used as water mass indicators. The former included the three most abundant species, whereas the latter showed greater species richness. This study provides basic knowledge on spatial distribution of siphonophores, which is important to develop future research focused on understanding the ecological role and biological processes driven by planktonic organisms in the southeastern Pacific Ocean.
This work provides a first taxonomic description of appendicularians collected during September a... more This work provides a first taxonomic description of appendicularians collected during September and August of 1995 in the north coast of Chile (18º23'-31º00' S). Fifteen species were identified. They belong to the families Oikopleuridae (Oikopleura longicauda, O. cophocerca, O. dioica, O. rufescens, O. fusiformis, O. albicans, O. gracilis and Megalocercus abyssorum), and Fritillariidae (Fritillaria pellucida typica, F. pellucida omani, F. haplostoma F. tenella, F. formica digitata, F. venusta and F. fraudax). All the species are first records for waters of northern Chile, thus broadening their previous distribution in the southeast Pacific. The most abundant species were Oikopleura longicauda (56.1 %), O. gracilis (10.4 %), Fritillaria pellucida typica (6.7 %); O. albicans (5.0 %); F. pellucida omani (4.7 %); O. cophocerca (4.4 %) and F. venusta (4.1 %), whereas the eight remaining species, constituted 8.6 % of the total appendicularians collected.
The macrozooplancton composition and distribution in the Magellan fjords were analyzed in October... more The macrozooplancton composition and distribution in the Magellan fjords were analyzed in October 1998. Samples were collected from 200 m depth to the surface using a Bongo net (200 mesh size). The area of study was characterized by its low specific diversity. Four chaetognath species, five euphausiids and seven siphonophores were identified. The dominant species were, Sagitta tasmanica, Euphausia vallentini and Muggiaea atlantica and their highest abundance’s were observed in the innermost stations, mainly inside the Otway, Almirantazgo and Agostini Sounds. The zooplanktonic biomass was low, with a mean of 85.28 ml/1.000 m 3 . High relative values were observed in the Almirantazgo and Agostini Sounds, and in the southern part of the Beagle Channel.
This study identifies the abundance and spatial distribution of siphonophores collected during sp... more This study identifies the abundance and spatial distribution of siphonophores collected during spring of 2011 between the Reloncaví Fjord and the Boca del Guafo Passage, in the Chiloé Inland Sea (CIS), Chile. Nine species of siphonophore were identified (three Physonectae and six Calycophorae), of which Agalma elegans, Cordagalma ordinatum and Lensia meteori were recorded for the first time in the waters of the CIS. The dominant species were Muggiaea atlantica (88.0%) and Lensia conoidea (9.5%). The highest occurrence frequency was recorded for M. atlantica (81.2%) and L. conoidea (62.5%). Eudoxids were collected only for M. atlantica (52.1%), L. conoidea (43.7%) and Dimophyes arctica (4.2%). The highest siphonophore densities were found in the northern microbasin (Reloncaví Fjord, Reloncaví and Ancud gulfs), an area characterised by a predominance of estuarine waters (greater vertical stratification, lower temperatures and salinity, and a higher concentration of dissolved oxygen). The vertical distribution patterns showed that M. atlantica is found throughout the water column in the northern microbasin, though with preference for the depths of 0-50 m. In the southern microbasin it was distributed mainly in deeper waters (>50 m). L. conoidea tends to avoid the surface estuarine layer (0-25 m) and is mainly distributed through deeper layers (>25 m). The association with environmental variables shows that temperature and dissolved oxygen have a significantly influence over dominant species. Siphonophorae community showed unimodal responses to the environmental gradients and high interspecific variability compared with previous campaigns in the same geographical area.
We have compiled available records in the literature for medusozoan cnidarians and ctenophores of... more We have compiled available records in the literature for medusozoan cnidarians and ctenophores of South America. New records of species are also included. Each entry (i.e., identified species or still as yet not determined species referred to as “sp.” in the literature) includes a synonymy list for South America, taxonomical remarks, notes on habit, and information on geographical occurrence. We have listed 800 unique determined species, in 958 morphotype entries: 5 cubozoans, 905 hydrozoans, 25 scyphozoans, 3 staurozoans, and 20 ctenophores. Concerning nomenclatural and taxonomical decisions, two authors of this census (Miranda, T.P. & Marques, A.C.) propose Podocoryna quitus as a nomen novum for the junior homonym Hydractinia reticulata (Fraser, 1938a); Euphysa monotentaculata Zamponi, 1983b as a new junior synonym of Euphysa aurata Forbes, 1848; and Plumularia spiralis Milstein, 1976 as a new junior synonym of Plumularia setacea (Linnaeus, 1758). Finally, we also reassign Plumula...
Beroe gracilis Künne, 1939 is a small neritic ctenophore, previously recorded only from cold wate... more Beroe gracilis Künne, 1939 is a small neritic ctenophore, previously recorded only from cold waters of the northern hemisphere. The present study provides the first record of the species in the southern hemisphere, found in the surface layer of the Humboldt Current System off the central Chilean coast (32°-36.5° S). A complete description of this material is provided.
ABSTRACT. Seamounts are vulnerable marine ecosystems. In Chile, information on these ecosystems i... more ABSTRACT. Seamounts are vulnerable marine ecosystems. In Chile, information on these ecosystems is quite scarce; thus, a compilation of information on their geographical distribution and biodiversity is presented herein. A total of 118 seamounts distributed in the Chilean EEZ are identified and characterized. Additionally, an in situ assessment was carried out on the Juan Fernandez seamounts 1 and 2 (JF1 and JF2), which were also oceanographically characterized. Phytoplankton, zooplankton, and marine invertebrate samples were collected and an exploratory fishing survey was executed using different gears. According to the bibliographical review, a total of 82 species have been collected on the JF1 and JF2 seamounts, highlighting findings of black coral species caught in lobster traps at the Juan Fernandez Archipelago. Submarine images of the marine substrate at JF1 and JF2 reveal characteristics attributable to the impact of bottom dredges, coinciding with the informa-tion obtained f...
<i>Nemopsis mianzani</i> n. sp. (Figure 1–2; Table 1) <b>Material examined.<... more <i>Nemopsis mianzani</i> n. sp. (Figure 1–2; Table 1) <b>Material examined.</b> Holotype: Male medusa with 9.5 mm in length. 11.xi. 2013. Off Dichato, Chile (36 ° 30 'S, 73 °05'W) (MNHNCL/CNID- 15001); Paratypes: Two female medusa with 9.3 and 8.9 mm in length. 11.xi. 2013. Off Dichato, Chile (36 ° 30 'S, 73 °05'W) (ZOOTIMO 201404). Length of umbrella, from top to edge 9.48 mm Diameter or umbrella at the top of the gastric cavity 7.53 mm Diameter or umbrella at the edge 7.48 mm Length of subumbrella 5.69 mm Diameter or subumbrella at the edge 6.62 mm Width of velum 480–546 μm Diameter of gastric cavity 3.24 mm Length of gastric cavity, from top to the edge of manubrium 2.59 mm Diameter of manubrium 1.08 mm Length of oral tentacles up to 1.49 mm Diameter of oral tentacles at the base 171–183 μm Number of oral tentacle ramifications up to 7 Diameter of nematocyst aggregations at the oral tentacles extremities up to 47 μm Distance between radial canals 2.61 mm Diameter of radial canal 193–208 μm Tentacular bulb length up to 3.06 mm Number of filiform tentacles per bulb 26–30 Diameter of filiform tentacles tentacles at the base 80–95 μm Diameter of club-shaped tentacles at the base 109 μm Length of the club-shaped tentacles up to 1.36 mm Diameter of the club-shaped tentacle ocellum 30 μm Diameter of the filiform tentacle ocellum 72–79 μm <b>Description.</b> Medusa. Umbrella bell-shaped, transparent, about 1.5 times higher than wide, with top and sides curved. Thick apical jelly, about 2 / 5 of bell-height. Four interradial subumbrellar pockets projecting into apical jelly. Four radial canals connected to a thin ring canal near broad marginal bulbs. Bulbs curved with 23-29 filiform tentacles. In some bulbs, a pair of short club-shaped tentacles is present in the median portion, inserted above the filiform tentacles. Ocelli at the base of each filiform tentacle, and on a swelling near the base in club-shaped tentacles. Manubrium conical, ending in a mouth with four short lips. Base of manubrium with perradial lobes res [...]
We analyze for the first time the spatial distribution of siphonophores in relation to water mass... more We analyze for the first time the spatial distribution of siphonophores in relation to water masses along a 3750-km oceanic transect between the Chilean coast and the Easter Island (27° S), a sector scarcely known of eastern South Pacific Ocean. Thirty-one siphonophore species ...
Blooms of stinging pelagic cnidarians have been causing increasing health problems for humans wor... more Blooms of stinging pelagic cnidarians have been causing increasing health problems for humans worldwide. Physalia physalis is among the worst stinging species in the Atlantic and Pacific oceans along the North and South American coasts. This siphonophore species has a large gas float and lives at the ocean surface, where its distribution is affected mainly by winds. P. physalis's strandings were observed in the southeastern Pacific Ocean for three consecutive years (2014 to 2016). Data of stranded P. physalis were gathered daily through a collaborative effort between the Chilean Navy and the Chilean Ministry of Health. The association between oceanographic variables and the stranded P. physalis was assessed using a generalized additive mixed model (GAMM) and cross-correlation analysis. The largest stranding occurred along more than 2600 km of coastline and totaled 44,683 colonies. Most of the strandings were along the central and south-central coast of Chile, where almost 200 pe...
Journal of the Marine Biological Association of the United Kingdom, 2016
This study characterizes the abundance and spatial distribution of siphonophores between the Trin... more This study characterizes the abundance and spatial distribution of siphonophores between the Trinidad Channel (50°06′S) and the Strait of Magellan (52°45′S) in southern Chile, during October–November 2009. Ten species were identified, of which Agalma elegans, Rosacea plicata and Sphaeronectes fragilis are new records for this region. Dominant species showed similar dominance values e.g. Lensia conoidea (26.3%), Dimophyes arctica (24.6%), Lensia meteori (22.2%) and Muggiaea atlantica (20.7%). Eudoxids of L. conoidea and D. arctica represented 97.3% of all eudoxids collected and they were mainly collected in estuarine waters. The highest densities were found in estuarine waters (high vertical stratification and low temperature, salinity and dissolved oxygen values). On the other hand, the lowest densities were found in coastal areas influenced by permanent influx of Sub-Antarctic waters from the Pacific (greater instability and vertical mixing, higher temperatures, salinity and dissol...
La clase Thaliacea, conformada por salpas, doliólidos y pyrosomas, son organismos filtradores hol... more La clase Thaliacea, conformada por salpas, doliólidos y pyrosomas, son organismos filtradores holoplanctónicos, frecuentemente son uno de los mayores componentes de la biomasa zooplanctónica en la capa superficial más cálida y templada de los océanos (Blackburn, 1979). Los doliólidos, son el grupo menos estudiado de la clase Thaliacea, a pesar que sus primeros registros datan de 1835, cuando Quoy y Gaimard se refirieron al género Doliolum en su reporte sobre la Expedición "Astrolabe" (1826-1829) al Pacífico tropical. El estudio de estos tunicados se intensificó en la segunda mitad del siglo XX, cuando los científicos comenzaron a comprender el complejo ciclo de vida de estos organismos (Esnal & Daponte, 1999).
We determined the distribution and abundance of pelagic copepods in the eastern equatorial Pacifi... more We determined the distribution and abundance of pelagic copepods in the eastern equatorial Pacific between the coast of Ecuador and the Galapagos Islands under oceanographic conditions associated with the weak La Niña event of 2001. In September-October 2001, negative anomalies of sea surface temperature from this event still remained in the eastern equatorial Pacific, mainly between Ecuador and the Galapagos Islands. The event allowed the incursion of the Humboldt Current farther north and of the Equatorial Undercurrent into the study area, favouring a strong Equatorial Front and upwelling processes. There was evidence of mesoscale eddies in the study area and of the presence of the South Equatorial Current going westward at about 1°N. We identified 107 copepod species and analyzed the distribution of the 10 most abundant ones: Oncaea venusta, Subeucalanus pileatus, S. crassus, S. subtenuis, Paraeucalanus attenuatus, Pleuromamma borealis, Scolecithrix danae, Clausocalanus farrani, Temora discaudata and Calanus chilensis. Copepod distribution and abundance exhibited marked latitudinal differences related to the oceanographic conditions; abundance was highest to the southeast of the Galapagos Islands. Oncaea venusta, Pleuromamma borealis, Calanus chilensis, and Subeucalanus subtenuis were the species that best defined the Equatorial Front and the upwelling process.
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Papers by Sergio Palma