Structure of hyperiid amphipod assemblages on Isla Gorgona, eastern tropical Pacific off Colombia

2011 ◽  
Vol 92 (7) ◽  
pp. 1489-1499 ◽  
Author(s):  
Bellineth Valencia ◽  
Alan Giraldo
Keyword(s):  
Similarity Index ◽  
Zooplankton Community ◽  
Sampling Period ◽  
Gelatinous Zooplankton ◽  
Tropical Pacific ◽  
Dry Season ◽  
The Other ◽  
Subsurface Water ◽  
Eastern Tropical Pacific ◽  
Entire Sampling Period

Temporal variation of hyperiid amphipod structure assemblages was studied on Isla Gorgona, eastern tropical Pacific (ETP) off Colombia between September 2005 and August 2006. Forty-six species were found during the entire sampling period:Hyperioides sibaginis, Lestrigonus bengalensis, Phronimopsis spinifera, Tetrathyrus forcipatusandParalycaea gracilisdominated the assemblage, representing 92%. The dendogram based on the Bray–Curtis similarity index showed that the hyperiid assemblages were separated into two groups, which did not coincide with the seasonality described for the ETP (wet versus dry season). Rather, groups comprised wet (May to November) and dry season months (December to April). The first group included November, December, February and March. During these months, significantly higher hyperiid richness, diversity and abundance were found, although colder subsurface water temperatures in Gorgona were registered only during February and March. The other group included May to October and January, and was characterized by lower hyperiid diversity and abundance values. Significant correlations were found between hyperiid abundance and the possible gelatinous zooplankton hosts (medusae, siphonophores and salps). This study contributes to increasing knowledge of the zooplankton community in the Panama Bight, as well as of a poorly studied group in the ETP.

A new species of Mysidium (Peracarida: Mysida: Mysidae) from the eastern tropical Pacific

2016 ◽  
Vol 97 (1) ◽  
pp. 113-117
Author(s):  
Manuel Ortiz ◽  
Michel E. Hendrickx ◽  
Ignacio Winfield
Keyword(s):  
New Species ◽  
Pacific Ocean ◽  
Tropical Pacific ◽  
The Other ◽  
Eastern Tropical Pacific ◽  
The Pacific ◽  
Appendix Masculina ◽  
The Pacific Ocean ◽  
A New Species

A new species of Mysidium from the eastern tropical Pacific, Mexico, is described, representing the second species of this genus described for the Pacific Ocean and the eighth species reported worldwide. Mysidium pumae sp. nov. is distinguished from the other species of the genus by several characters including: the lanceolate appendix masculina, 3× as long as wide, tapering distally, with a distal tuft of 16 setae and an inner proximal tuft of more than 30 setae, the male pleopod 4 with endopod bearing 3 setae, the exopod with 4 articles, the modified seta from article 3 of the exopod bifid, telson 2.3× as long as wide, distally concave. A table with the main differences among all the known species in the genus is provided.

scholarly journals The Interaction of Clouds and Dry Air in the Eastern Tropical Pacific

2006 ◽  
Vol 19 (18) ◽  
pp. 4531-4544 ◽  
Author(s):  
Paquita Zuidema ◽  
Brian Mapes ◽  
Jialin Lin ◽  
Chris Fairall ◽  
Gary Wick
Keyword(s):  
Vertical Structure ◽  
Tropical Pacific ◽  
The Other ◽  
Horizontal Wind ◽  
Positive Temperature ◽  
Eastern Tropical Pacific ◽  
Dry Air ◽  
Cloud Radar ◽  
Subsidence Zone ◽  
Differential Advection

Abstract Cloud radar observations of eastern Pacific intertropical convergence zone cloud vertical structure are interpreted in light of soundings, 100-km-scale divergence profiles calculated from precipitation radar Doppler velocities, and surface rain gauge data, from a ship at 10°N, 95°W during the 2001 East Pacific Investigation of Climate (EPIC) experiment. The transition from convective to stratiform rain is clear in all four datasets, indicating a coherence from local to 100-km scale. A novel finding is dry air intrusions at altitudes of 6–8 km, often undercutting upper-level ice clouds. Two distinct dry air source regions are identified. One is a relatively dry area overlying the cooler waters of the Costa Rica oceanic thermocline dome, centered approximately 400 km east-northeast of the ship site. The other is the even drier near-equatorial subsidence zone south of 6°–7°N. The former source is somewhat peculiar to this specific ship location, so that the ship sample is not entirely representative of the region. The 20–25 September period is studied in detail, as it depicts two influences of the dry air on cloud vertical structure. One is the modulation of small-scale surface-based convection, evident as a weakening and narrowing of cloud radar reflectivity features. The other springs from intense sublimation cooling as differential advection brought snowing anvil clouds over the dry layers. During one half-day period of strong sublimation, the cooling rate is inferred to be several tens of degrees per day over a 100-hPa layer, based on a heat budget estimate at 100-km scale involving the horizontal wind divergence data. This is consistent with fluxing ice water contents of 0.05–0.10 g m−3 derived from the cloud radar reflectivities. The temperature profile shows the dynamically expected response to this cooling, a positive–negative–positive temperature anomaly pattern centered on the sublimating layer. A buoyancy-sorting diagnostic model of convection indicates that these upper-troposphere temperature anomalies can cause premature detrainment of updrafts into the lower part of the cloudy layer, a feedback that may actively maintain these long-lasting dense anvils. Middle-troposphere southerly dry air inflow is also evident in large-scale analysis. Given the proximity of the dry equatorial subsidence zone to the eastern tropical Pacific, the differential advection of dry and cloudy air, the ensuing sublimation, and its dynamical aftereffects may play a role in establishing the region’s climate, although the extent of their significance needs to be further established.

A new genus and new species of hermit crab (Crustacea: Anomura: Paguroidea: Diogenidae) from the eastern tropical Pacific

Zootaxa ◽  
2010 ◽  
Vol 2677 (1) ◽  
pp. 49
Author(s):  
MANUEL AYÓN-PARENTE ◽  
MICHEL E. HENDRICKX
Keyword(s):  
New Species ◽  
Hermit Crab ◽  
Posterior Margin ◽  
New Genus ◽  
Tropical Pacific ◽  
The Other ◽  
Monotypic Genus ◽  
Eastern Tropical Pacific ◽  
The Family ◽  
A New Species

Tetralobistes gen. nov., a presently monotypic genus of hermit crab of the family Diogenidae, is described to accommodate a new species, Tetralobistes bicentenarius sp. nov. In many characters, Tetralobistes gen. nov. is similar to Areopaguristes Rahayu & McLaughlin, 2010, Paguristes Dana, 1851, and Pseudopaguristes Mclaughlin, 2002. However, it differs most significantly in the morphology of the male first pleopods and lacks male second and female first pleopods. The most conspicuous character separating Tetralobistes gen. nov. from the other three genera is the shape of the telson, with a typical subdivided (four-lobes) posterior margin.

New records of gelatinous zooplankton from an oceanic island in the Eastern Tropical Pacific

2017 ◽  
Vol 98 (6) ◽  
pp. 1219-1226
Author(s):  
Marco Corrales-Ugalde ◽  
Andrés J. Quesada ◽  
Beatriz Naranjo-Elizondo ◽  
Jorge Cortés
Keyword(s):  
New Records ◽  
First Record ◽  
Gelatinous Zooplankton ◽  
Tropical Pacific ◽  
Costa Rican ◽  
Oceanic Island ◽  
Eastern Tropical Pacific ◽  
Pelagic Environment ◽  
Present Information ◽  
Cocos Island

Gelatinous zooplankton are an abundant and diverse group of animals in the pelagic environment. However, knowledge of species diversity and spatial distributions, as well as their ecological role, is scarce. We present information of epi- and mesopelagic gelatinous zooplankton recorded by the ‘DeepSee’ submersible between 2006 and 2012 at Isla del Coco (Cocos Island), Costa Rica, an oceanic island in the Eastern Tropical Pacific. Two species of scyphomedusae, three species of hydromedusae, two genera of siphonophores, and two species of ctenophores were observed in the videos, at depths between 50 and 400 m. None of these species had been previously recorded in the waters around the island. Furthermore, except for the jellyfish Pelagia noctiluca and a siphonophore in the genus Praya, all are new records for Costa Rican waters. This study also includes the first record of the cnidarians Modeeria rotunda, Solmissus sp., Halitrephes maasi and Apolemia spp., and the ctenophore Thalassocalyce inconstans in the Eastern Tropical Pacific. We show that surveys in regions with little information about gelatinous zooplankton may broaden our knowledge of their natural history and may result in new records of gelatinous species.

Physical forcing and the dynamics of the pelagic ecosystem in the eastern tropical Pacific: simulations with ENSO-scale and global-warming climate drivers

2003 ◽  
Vol 60 (9) ◽  
pp. 1161-1175 ◽  
Author(s):  
George M Watters ◽  
Robert J Olson ◽  
Robert C Francis ◽  
Paul C Fiedler ◽  
Jeffrey J Polovina ◽  
...  
Keyword(s):  
Global Warming ◽  
Phytoplankton Biomass ◽  
Southern Oscillation ◽  
Tropical Pacific ◽  
Trophic Levels ◽  
Eastern Tropical Pacific ◽  
Ecosystem Models ◽  
Pelagic Ecosystem ◽  
Physical Forcing ◽  
Physical Effects

We used a model of the pelagic ecosystem in the eastern tropical Pacific Ocean to explore how climate variation at El Niño – Southern Oscillation (ENSO) scales might affect animals at middle and upper trophic levels. We developed two physical-forcing scenarios: (1) physical effects on phytoplankton biomass and (2) simultaneous physical effects on phytoplankton biomass and predator recruitment. We simulated the effects of climate-anomaly pulses, climate cycles, and global warming. Pulses caused oscillations to propagate through the ecosystem; cycles affected the shapes of these oscillations; and warming caused trends. We concluded that biomass trajectories of single populations at middle and upper trophic levels cannot be used to detect bottom-up effects, that direct physical effects on predator recruitment can be the dominant source of interannual variability in pelagic ecosystems, that such direct effects may dampen top-down control by fisheries, and that predictions about the effects of climate change may be misleading if fishing mortality is not considered. Predictions from ecosystem models are sensitive to the relative strengths of indirect and direct physical effects on middle and upper trophic levels.

scholarly journals The length of the dry season may be associated with leaf scleromorphism in cerrado plants

2015 ◽  
Vol 87 (3) ◽  
pp. 1691-1699 ◽  
Author(s):  
MARCELO C. SOUZA ◽  
AUGUSTO C. FRANCO ◽  
MUNDAYATAN HARIDASAN ◽  
DAVI R. ROSSATTO ◽  
JANAÍNA F. DE ARAÚJO ◽  
...  
Keyword(s):  
Soil Fertility ◽  
Specific Leaf Area ◽  
Woody Species ◽  
Dry Season ◽  
Core Region ◽  
The Other ◽  
Low Fertility ◽  
Fertility Rates ◽  
Cerrado Vegetation ◽  
Central Brazil

Despite limitations of low fertility and high acidity of the soils, the cerrado flora is the richest amongst savannas. Many cerrado woody species show sclerophyllous leaves, which might be related to the availability of water and nutrients in the soil. To better understand the function and structure of cerrado vegetation within its own variations, we compared two cerrado communities: one in its core region in central Brazil (Brasília, DF) and the other on its southern periphery (Itirapina, SP). We contrasted the length of the dry season, soil fertility rates, leaf concentrations of N, P, K, Ca and Mg and the specific leaf area (SLA) between these communities. The dry season was shorter on the periphery, where the soil was more fertile although more acidic. Plants from the periphery showed higher SLA and higher leaf concentrations of N, P, Ca and Mg. We propose that the higher SLA of plants from the periphery is related to the shorter dry season, which allows better conditions for nutrient uptake.

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