Southeastern Pacific Ocean Research Articles

Metazoan Parasites of Antimora rostrata (Günther, 1878) (Gadiformes: Moridae) from the Deep Sea in the Southeastern Pacific Ocean

A total of 127 specimens of the “Blue Antimora” Antimora rostrata (Günther, 1878) were obtained from 2015 to 2019 as bycatch from the artisanal fishery of the Patagonian toothfish (Dissostichus eleginoides (Smitt, 1898)) at depths between 1000 and 2200 m in Northern Chile (app. 22° S 70° W). All individuals were examined for parasites. A total of seventeen parasite taxa, two Copepoda, two Monogenea, seven Digenea, three Nematoda, and three Cestoda, were found, and twelve taxa were found as adults while five taxa were found at the larval stage. Anisakis sp. (Nematoda) and Trypanorhyncha gen. sp. (Cestoda) were the predominant species with a prevalence of 53.5% and 11.8%, respectively. The high prevalence of Anisakis sp. (>50%) suggests that A. rostrata may play a significant role in the life cycle of Anisakis sp. in the southeastern Pacific Ocean. The detected parasite community, consisting predominantly of parasites from pelagic environments rather than benthopelagic, suggests that A. rostrata may fulfill a crucial role as a predator of pelagic organism communities. Additionally, it may undertake vertical migrations in the southeastern Pacific Ocean.

Morphospace of lanternfish larvae and their interplay with oceanographic conditions from the southeastern Pacific Ocean

Lanternfish larval morphology is highly variable probably due to their adaptations to highly variable environmental conditions throughout ontogeny. To study the morphological variability of the larval stage of lanternfishes, samples were collected from the southeast Pacific Ocean between 2014 and 2022. Of the 24 species, nine belonged to the subfamily Lampanyctinae, two to the subfamily Diaphinae, one to the subfamily Notolychinae, one to the subfamily Gymnoscopelinae and 11 to the subfamily Myctophinae. A principal component analysis indicated the presence of body shapes varying from a slender and curved body, and upper jaw oriented downwards, with relatively rounded eyes, to taxa with robust bodies, particularly both the head and trunk, and elongated eyes in a dorsal-ventral plane (PC1 33%). Also, specimens varied from having short jaw, short snout, and slender body, to specimens with larger jaw (reaching behind the eye) and taller snout and trunk (PC2, 23%). Allometric effects were related to variations in body curvature and thickness (Diaphus theta, 12.9%), the curvature of the body and position of the eyes (Lampanyctodes hectoris, 25.1%), lengthening of the jaw and increase in eye size (Diogenichthys atlanticus, 24.6%), and a narrower body and smaller eyes (Hygophum bruuni, 20.5%). Four of the five subfamilies showed covariation between morphometrics and environmental conditions. Diaphinae, Gymnoscopelinae and Lampanyctinae body shape covaried with mean sea temperature of the water column, while Myctophinae larval shape covaried with mean salinity. In conclusion, this study quantifies shape variations during early lanternfish ontogeny from the southeastern Pacific Ocean, identifying main differences and allometric changes between the subfamilies belonging to Myctophidae, with a covariation between the shape of most lanternfish larvae and the environmental conditions experienced by myctophid early stages.

Study of the Weddell Sea Anomaly Using Novel Satellite Altimeter TEC Maps

AbstractThe Weddell Sea Anomaly (WSA) is a phenomenon of unique intensity and geographic extent that occurs in December (Southern Hemisphere summer) over the southeastern Pacific and southwestern Atlantic oceans regions. Historically, the classic definition of the WSA refers to a situation in which the midnight NmF2 (or TEC) values are greater than the noon NmF2 (or TEC) values. However, several articles published in the last decades have shown that the WSA is a much more complex phenomenon, and its definition might need to be reformulated. This paper presents a phenomenological description of the WSA using a novel type of vertical Total Electron Content (TEC) maps, obtained from altimeter satellite TEC data. The focus of this study is on the possible connection between the WSA and the unexpected expansion and contraction periods observed on the Equatorial Ionospheric Anomaly (EIA) throughout the Southern Hemisphere. The data analysis revealed that the WSA is only one of a number of observed anomalies. Furthermore, we show a significant correlation between the behavior of the EIA and the Y component of the geomagnetic field, which maximizes in the WSA region. We then present a possible hypothesis for interpreting these results.

Genomics resources for the Rapa Nui (Eastern Island) spiny lobster Panulirus pascuensis (Crustacea: Decapoda: Achelata)

BackgroundThe Easter Island spiny lobster Panulirus pascuensis (Reed, 1954) or ‘Ura’ in the Rapa Nui language, is a little known species native to the south eastern Pacific Ocean, distributed along the coasts of Easter Island, Pitcairn Island, and the Salas y Gómez Ridge. In Easter Island, P. pascuensis is the target of a small and profitable and probably overexploited fishery. In this study, we profited from a series of bioinformatic analyses to mine biological insight from low-pass short-read next generation sequencing datasets; we have estimated genome size and ploidy in P. pascuensis using a k-mer strategy, discovered, annotated, and quantified mobile elements in the nuclear genome, assembled the 45S rRNA nuclear DNA cassette and mitochondrial chromosome, and explored the phylogenetic position of P. pascuensis within the genus Panulirus using the signal retrieved from translated mitochondrial protein coding genes.ResultsK-mer analyses predicted P. pascuensis to be diploid with a haploid genome size ranging between 2.75 Gbp (with k-mer = 51) and 3.39 Gbp (with k-mer = 18). In P. pascuensis, repetitive elements comprise at least a half and a maximum of three fourths of the nuclear genome. Almost a third (64.94%) of the repetitive elements present in the studied nuclear genome were not assigned to any known family of transposable elements. Taking into consideration only annotated repetitive elements, the most abundant were classified as Long Interspersed Nuclear Elements (22.81%). Less common repetitive elements included Long Terminal Repeats (2.88%), Satellite DNA (2.66%), and DNA transposons (2.45%), among a few others. The 45S rRNA DNA cassette of P. pascuensis was partially assembled into two contigs. One contig, 2,226 bp long, encoded a partially assembled 5′ ETS the entire ssrDNA (1,861 bp), and a partial ITS1. A second contig, 6,714 bp long, encoded a partially assembled ITS1, the entire 5.8S rDNA (158 bp), the entire ITS2, the entire lsrDNA (4,938 bp), and a partial 3′ ETS (549 bp). The mitochondrial genome of P. pascuensis was 15,613 bp long and contained 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, and two ribosomal RNA genes (12S ribosomal RNA [rrnS] and 16S ribosomal RNA [rrnL]). A phylomitogenomic analysis based on PCGs retrieved Panulirus pascuensis as sister to a fully supported clade comprising P. cygnus and P. longipes.ConclusionWe expect that the information generated in this study will guide the assembly of a chromosome-level nuclear genome for P. pascuensis in the near future. The newly assembled 45S rRNA nuclear DNA cassette and mitochondrial chromosome can support bioprospecting and biomonitoring of P. pascuensis using environmental DNA. The same elements can help to survey the public market place and detect mislabelling of this and other spiny lobsters. Overall, the genomic resources generated in this study will aid in supporting fisheries management and conservation strategies in this iconic spiny lobster that is likely experiencing overexploitation.

Multidecadal variations in North Atlantic SSTs modulate the relationship between ENSO and the South Atlantic Subtropical Dipole since 1900

Abstract This study investigates the long-term variability of the relationship between the El Niño South/Oscillation (ENSO) and the South Atlantic Subtropical Dipole (SASD), and their connection to multidecadal variations in the North Atlantic sea surface temperature (MDV-SST). Using a century’s worth of SST and atmospheric data and the Community Atmosphere Model version 5, the study found significant interdecadal variability in the correlation between the Niño3.4 index and the SASD index. This variability is closely linked to the North Atlantic MDV-SST, often interpreted as Atlantic Multidecadal Oscillation (AMO). This is demonstrated by significant ENSO-SASD correlations during warm (positive) phases of MDV-SST (1930–1960 and 2001–2020) and insignificant correlations during cold (negative) phases (1900–1929 and 1961–2000). Through a Gill-type response, MDV-SST excites Rossby wave over the tropical Pacific Ocean, influencing surface wind, SST, convective activities and upper-level zonal wind over the Pacific Ocean. During warm MDV-SST phases, the more eastward positioned Rossby wave source (RWS), triggered by SST and precipitation anomalies over the South Pacific Ocean, along with a stronger, more northward subtropical jet stream, propagates the wavetrain more eastwards into the South Atlantic Ocean, thereby strengthening the SST anomalies in the SASD. Conversely, during the cold MDV-SST phases, the more westward-positioned ENSO-related RWS and a stronger mid-latitude jet stream guide the wavetrain southeastwards into the southeastern Pacific Ocean, exerting less influence on the SST anomalies in the SASD. The Ekman pumping caused by anomalous surface pressure and the associated surface wind field as well as surface turbulent heat flux also affect the SST anomalies in the SASD and the ENSO-SASD relation.

Freshwater discharge drives latitudinal changes of phytoplankton composition on the continental shelf off Chilean Patagonia

A high-resolution survey of distribution, abundance and composition of phytoplankton was carried out for the first time in surface waters of the continental shelf off Chilean Patagonia (41–48°S). An Imaging FlowCytobot was used along the survey track to record phytoplankton in the size range of 10–120 μm during the austral spring of 2018. Phytoplankton community structure was complemented with continuous underway measurements of temperature and salinity, and physicochemical parameters of the water column at 35 oceanographic stations. Our results evidenced two main macrozones with distinctive phytoplankton assemblages delimited latitudinally at ~45°S. The northern macrozone was characterized by higher surface temperature and salinity, Si:N ratio > 1, diatoms of the genera Thalassiosira and Chaetoceros, and dinoflagellates accounting for over 70% of the total abundance. The southern macrozone, with lower surface temperature and salinity and Si:N ratio < 1, was characterized by members of the genera Guinardia, Lauderia and Cerataulina, representing over 60% of the total phytoplankton. These changes were attributable to the strong influence of freshwater at latitudes higher than 45°S and the enhanced discharge of meltwaters from Patagonian icefields in the area of the Taitao Peninsula and the Gulf of Penas (47–-48°S). Fresh and cold waters impacted the water column stratification and the availability of dissolved silicic acid with potential effects on phytoplankton composition and diatom cell silicification and, thus, on carbon exportation. Our estimations of phytoplankton carbon were comparable to those observed in Patagonian fjords and the highly productive upwelling ecosystem of central Chile. We suggest that the continental shelf off Patagonia can contribute significantly to strengthen the biological carbon pump through the synthesis, exportation, and sequestration of phytoplankton-based organic carbon in the southeastern Pacific Ocean.

Molecular identification and prevalence of plerocercoid larvae (Cestoda: Diphyllobothriidae) in some commercial fish species from Peru.

Diphyllobothriosis, a fish-borne zoonosis in South America, is mainly caused by the Pacific broad tapeworm Adenocephalus pacificus Nybelin, 1931, a parasite of considerable concern in fishery resources due to its impact on public health. A new diphyllobothrid, Diphyllobothrium sprakeri Hernández-Orts et al. Parasites Vectors 14:219, 2021, was recently described from sea lions from the Pacific Coast, but marine fish acting as intermediate hosts are unknown. The objective of this study was to confirm the presence of plerocercoid larvae of Diphyllobothriidae Lühe, 1910 (Cestoda: Diphyllobothriidea) in nine fish species of commercial importance in Peru. Of a total of 6999 fish (5861 Engraulis ringens, 853 Sciaena deliciosa, 6 Sciaena callaensis, 171 Scomber japonicus, 40 Trachurus murphyi, 40 Ariopsis seemanni, 18 Merluccius peruanus, 5 Sarda chiliensis, and 5 Coryphaena hippurus), 183 were infected with plerocercoid larvae, representing a total prevalence of 2.61% and a mean intensity of 3.2. Based on mtDNA cox1 sequences of 43 plerocercoids, a phylogenetic analysis revealed that 41 belong to A. pacificus and two to D. sprakeri. These findings are first molecular data for D. sprakeri larvae, and the infections of E. ringens and T. murphyi by plerocercoid larvae represent the first records of intermediate/paratenic hosts for this species. Hence, the findings of the current study enhance our understanding of the presence of diphyllobothriid species in commercial fish from the Southeastern Pacific Ocean and their potential impact on seafood safety for local human populations.

Simulating drifting fish aggregating device trajectories to identify potential interactions with endangered sea turtles.

Purse-seine fishers using drifting fish aggregating devices (dFADs), mainly built with bamboo, plastic buoys, and plastic netting, to aggregate and catch tropical tuna, deploy 46,000-65,000 dFADs per year in the Pacific Ocean. Some of the major concerns associated with this widespread fishing device are potential entanglement of sea turtles and other marine fauna in dFAD netting; marine debris and pollution; and potential ecological damage via stranding on coral reefs, beaches, and other essential habitats for marine fauna. To assess and quantify the potential connectivity (number of dFADs deployed in an area and arriving in another area) between dFAD deployment areas and important oceanic or coastal habitat of critically endangered leatherback (Dermochelys coriacea) and hawksbill (Eretmochelys imbricata) sea turtles in the Pacific Ocean, we conducted passive-drift Lagrangian experiments with simulated dFAD drift profiles and compared them with known important sea turtle areas. Up to 60% of dFADs from equatorial areas were arriving in essential sea turtle habitats. Connectivity was less when only areas where dFADs are currently deployed were used. Our simulations identified potential regions of dFAD interactions with migration and feeding habitats of the east Pacific leatherback turtle in the tropical southeastern Pacific Ocean; coastal habitats of leatherback and hawksbill in the western Pacific (e.g., archipelagic zones of Indonesia, Papua New Guinea, and Solomon Islands); and foraging habitat of leatherback in a large equatorial area south of Hawaii. Additional research is needed to estimate entanglements of sea turtles with dFADs at sea and to quantify the likely changes in connectivity and distribution of dFADs under new management measures, such as use of alternative nonentangling dFAD designs that biodegrade, or changes in deployment strategies, such as shifting locations.

Lagged effect of Southern Annular Mode on chlorophyll-a in the mid-latitude South Pacific and Indian Oceans

This study investigates the influence of the Southern Annular Mode (SAM) on chlorophyll-a (Chl-a) concentrations and the underlying mechanisms governing their associated environmental variations in the mid-latitude (35–50° S) ocean from 1998 to 2021. The intensification of westerly winds during positive SAM phases influences meridional water transport and mixed layer depth (MLD), which are both critical factors that affect surface nutrient availability. A marked contrast in the relationship between the meridional current anomaly and the SAM was observed, with reduced northward transport of nutrient-rich water in regions north of 50° S during positive SAM phases. This reduction could be attributed to the poleward migration of the westerly winds, which impeded the meridional current from reaching the mid-latitudes. The relationship between SAM and MLD south of 50° S was positive whereas that in the mid-latitude eastern (60–110° E) South Indian Ocean and eastern (90–140° W) South Pacific Ocean was negative or weak. The immediate effect of a more positive SAM on Chl-a in the mid-latitude ocean was reduced productivity caused by enhanced nutrient depletion. However, in the mid-latitude eastern South Pacific Ocean, the northward migration of the zonal mean meridional current anomaly closely aligned with the lagged correlation pattern between SAM variability and Chl-a over time, suggesting that the delayed northward transport of nutrient-rich waters may partially counterbalance the immediate effects of the SAM on ocean productivity. This mechanism was not present in the mid-latitude eastern South Indian Ocean, implying that future climate change may variably affect these regions. Our findings emphasize the importance of considering regional differences and temporal lags when evaluating the influence of SAM variability on ocean productivity and nutrient dynamics in the context of climate change.

Patterns of variability of species composition of catches from the russian fishing vessels in the south-eastern Pacific ocean for 2015–2022

The work provides information on the patterns of species composition of catches from the Russian fishing vessels conducted fishing of jack mackerel (Trachurus murphyi Nichols 1920), chub mackerel (Scomber japonicus Houttuyn 1782) and redbait (Emmelichthys spp.) in the South-Eastern Pacific Ocean outside the economic zones of the coastal States. According to scientific observations, an analysis of the composition of species caught by the Russian fishing vessels is given. When fishing in the pelagic zone over ocean depths, jack mackerel was the main target species, chub mackerel formed the bycatch. At the same time, the proportion of chub mackerel in catches in the northern parts was higher than in the southern ones. When fishing on seamounts of the Nazca Ridge, catches were dominated by redbait with jack mackerel and alfonsino (Beryx splendens Lowe, 1834) as bycatch. According to the similarity of the species composition of catches, three areas – 1) all the Southern and Central subareas and part of the Northern subarea; 2) seamounts of Nazca ridge; 3) part of the Northern subarea near the border of the EEZ of Peru between 17–20°S, were singled out using the cluster analysis method.

Russian fishing in the Atlantic and Southeastern Pacific Oceans in 2000–2020

The aim: to analyze the development of domestic fisheries in the Atlantic and Southeastern Pacific Oceans in 2000–2020, to assess the state of stocks and catch of the most important types of aquatic biological resources.Methods: conducting trawl-a coustic, ichthyological and hydrological accounting studies in 2000–2020. Analysis of domestic and foreign literature.Novelty: the article presents an up-to-date analysis of the development of Russian fishing, the intensity of fishing and the state of exploited stocks of commercial fish species.Results: Information is provided on the status and dynamics of stocks and catch of commercial aquatic organisms in various areas of the Atlantic and southeastern Pacific Ocean. During the period under review, the highest biomass of stocks and catch are observed in pelagic fish species in the North-East Atlantic. The state of stocks and catch of bottom fish species in the far North Atlantic regions are at an average or low level. In general, in the first two decades of the XXI century, favorable conditions for conducting domestic fishing were noted. For the Central-Eastern Atlantic area (EEZ of Morocco and Mauritania), information is provided on the status of the main commercial fish stocks. Particular attention was paid to the possibility of resuming the domestic tuna and mackerel fishery in the south-e astern Pacific Ocean.Practical significance: the results of the analysis can be used to make management decisions on the development and regulation of fishing.

Insights into the genome of the ‘Loco’ Concholepas concholepas (Gastropoda: Muricidae) from low-coverage short-read sequencing: genome size, ploidy, transposable elements, nuclear RNA gene operon, mitochondrial genome, and phylogenetic placement in the family Muricidae

BackgroundThe Peruvian ‘chanque’ or Chilean ‘loco’ Concholepas concholepas is an economically, ecologically, and culturally important muricid gastropod heavily exploited by artisanal fisheries in the temperate southeastern Pacific Ocean. In this study, we have profited from a set of bioinformatics tools to recover important biological information of C. concholepas from low-coverage short-read NGS datasets. Specifically, we calculated the size of the nuclear genome, ploidy, and estimated transposable elements content using an in silico k-mer approach, we discovered, annotated, and quantified those transposable elements, we assembled and annotated the 45S rDNA RNA operon and mitochondrial genome, and we confirmed the phylogenetic position of C. concholepas within the muricid subfamily Rapaninae based on translated protein coding genes.ResultsUsing a k-mer approach, the haploid genome size estimated for the predicted diploid genome of C. concholepas varied between 1.83 Gbp (with kmer = 24) and 2.32 Gbp (with kmer = 36). Between half and two thirds of the nuclear genome of C. concholepas was composed of transposable elements. The most common transposable elements were classified as Long Interspersed Nuclear Elements and Short Interspersed Nuclear Elements, which were more abundant than DNA transposons, simple repeats, and Long Terminal Repeats. Less abundant repeat elements included Helitron mobile elements, 45S rRNA DNA, and Satellite DNA, among a few others.The 45S rRNA DNA operon of C. concholepas that encodes for the ssrRNA, 5.8S rRNA, and lsrRNA genes was assembled into a single contig 8,090 bp long. The assembled mitochondrial genome of C. concholepas is 15,449 bp long and encodes 13 protein coding genes, two ribosomal genes, and 22 transfer RNAs.ConclusionThe information gained by this study will inform the assembly of a high quality nuclear genome for C. concholepas and will support bioprospecting and biomonitoring using environmental DNA to advance development of conservation and management plans in this overexploited marine snail.

Doubling the known diversity of a remote island fauna: marine bivalves of the Juan Fernández and Desventuradas oceanic archipelagos (Southeastern Pacific Ocean).

Juan Fernández and Desventuradas are two oceanic archipelagos located in the southeastern Pacific Ocean far off the Chilean coast that received protected status as marine parks in 2016. Remoteness and access difficulty contributed to historically poor biodiversity sampling and limited associated research. This is particularly noticeable for bivalves, with most prior regional publications focused on single taxa or un-illustrated checklists. This study investigates marine bivalves collected between the intertidal and 415 m depth during (1) the 1997 IOC97 expedition aboard the M/V Carlos Porter, with special focus on scuba-collected micro-mollusks of both archipelagos, (2) two expeditions by the R/V Anton Bruun (Cruise 12/1965 and Cruise 17/1966), and (3) Cruise 21 of USNS Eltanin under the United States Antarctic Program, which sampled at Juan Fernández in 1965. Also, relevant historical material of the British H.M.S. Challenger Expedition (1873-1876), the Swedish Pacific Expedition (1916-1917), and by German zoologist Ludwig H. Plate (1893-1895) is critically revised. A total of 48 species are recognized and illustrated, including 19 new species (described herein) and six other potentially new species. The presence of two species mentioned in the literature for the region (Aulacomya atra and Saccella cuneata) could not be confirmed. The genera Verticipronus and Halonympha are reported for the first time from the Eastern Pacific, as are Anadara and Condylocardia from Chilean waters. Lectotypes are designated for Arca (Barbatia) platei and Mytilus algosus. These findings double the number of extant bivalve species known from the Juan Fernández and Desventuradas archipelagos, highlighting the lack of attention these islands groups have received in the past. A high percentage of species endemic to one or both archipelagos are recognized herein, accounting for almost 78% of the total. The newly recognized level of bivalve endemism supports the consideration of Juan Fernández and Desventuradas as two different biogeographic units (Provinces or Ecoregions) of the Eastern Pacific Ocean.

A new morphotype description of Arbacia spatuligera Valenciennes, 1846 (Arbacioida, Echinoidea) and bathymetric range extension from mesophotic reefs of the central coast of Chile

Abstract The sea urchin Arbacia spatuligera is an echinoid distributed in the Southeastern Pacific Ocean from Peru to Chile. This species was previously reported from the subtidal zone with a bathymetric distribution up to 30 m depth. In this work, 128 individuals were found in four mesophotic reefs along the central coast off Chile using closed-circuit rebreathers in technical diving at higher depths than previously, ranging from 36 to 63 m in depth. A population exhibits unexpected morphological characters, requiring an emended diagnosis and description of a new morphotype for A. spatuligera. These morphological traits are further discussed as potential ecophenotypic adaptations.

Heterogeneous Diazotroph Communities in the Subtropical‐Subantarctic Transition and Aphotic Zones Off the Coast of Patagonia, Eastern South Pacific Ocean

AbstractSubtropical‐subpolar transition water is a potential domain for N2 fixation, but the understanding of N2 fixation in such waters remains incomplete. We simultaneously examined the N2 fixation activity and community structures of diazotrophs and all prokaryotes from the surface to just above the seafloor off Patagonia in the transitional region of the eastern South Pacific Ocean. N2 fixation activity was not detected in the surface waters, but was observed sporadically and only in subpolar bathypelagic waters (&gt;1,000 m) at very low rates (0.02–0.06 nmol N L−1 d−1). By contrast, the nifH gene, a key gene involved in N2 fixation, was detected widely from the surface to the bottom waters. The majority of diazotrophs were classified as non‐cyanobacterial diazotrophs (NCDs), and the nifH amino acid sequences of major diazotrophs were similar to sequences detected in the Southern Ocean, the aphotic zone and sediment of other oceans, and estuarine waters, suggesting that the NCDs are distributed across diverse marine environments. The overall prokaryotic communities were generally similar to those in other open ocean regions at the phylum level (class level for Proteobacteria) and differed among water depths. Diazotrophs, in contrast, showed vertical and horizontal heterogeneity below the euphotic zone and little association with water depth, indicating a lack of cohesion within the community, which may characterize diazotroph community in the transitional surface water and aphotic zones. Elucidating this community heterogeneity may provide pivotal information about N2 fixation in these waters.

Proposal of Brotulella n. gen. for Monogeneans from the Gills of the Pacific Bearded Brotula Brotula clarkae Hubbs, 1944 (Ophidiiformes: Ophidiidae) Based on Morphological and Molecular Evidence

Based on morphological and molecular data, Brotulella n. gen. is proposed to accommodate the dactylogyrid monogeneans Brotulella laurafernandae n. sp. (type species) and Brotulella luisahelenae n. sp. on the gill filaments of the Pacific bearded brotula Brotula clarkae Hubbs, 1944 (Ophidiiformes: Ophidiidae) from Puerto Pizarro in the Tumbes region (northern Peru). Species of the new genus are distinguished from all other dactylogyrids by the combination of the following features: (1) anchors with a stocking-shaped sheath associated with the distal end of superficial and deep roots, (2) tandem gonads, (3) a vas deferens looping left intestinal caecum, (4) a distally twisted male copulatory organ (MCO) with a delicate membranous accessory piece articulated to the shaft of the MCO, (5) a U-shaped ovary, (6) an almost sigmoid seminal vesicle, and (7) two prostatic reservoirs with thick muscular walls. A 28S ribosomal DNA-based phylogenetic analysis (Maximum likelihood and Bayesian inference) of sequences of two new species of Brotulella n. gen. from the Southeastern Pacific Ocean, along with sequences from closely related genera of the marine Dactylogyridae, supports the establishment of the new genus for the dactylogyrid parasites on the gills of the Pacific bearded brotula.

First southeastern Pacific record of Balloon Alfonsin, Beryx mollis Abe, 1959 (Beryciformes, Berycidae), with notes on geographical meristic variations

Four specimens (151&amp;ndash;156 mm in standard length) of Beryx mollis Abe, 1959 were collected from the Nazca Ridge, southeastern Pacific Ocean. These specimens represent the first record of the species from the south-eastern Pacific Ocean and extend the distributional range of the species eastward by ca. 10,000 km from New Caledonia, the previously known eastern limit. Comparison with specimens from other regions reveals geographical variations of some meristic characters in the species.

Fog Water Collection for Local Greenhouse Vegetable Production in the Atacama Desert

Agricultural production in the Atacama Desert is restricted by extreme aridity and poor soil quality. Between 18° S and 30° S, low stratocumulus clouds regularly cover the southeastern Pacific Ocean reaching the Coastal Cordillera. Thus, marine fog is constantly present in the coastal areas of the desert. Fog can be harvested using fog collectors. However, limited information is available with regards to the variability of fog presence throughout the year and along the coast of the desert. Combining fog water harvest with hydroponic production under greenhouse facilities presents an alternative for sustainable and local fresh food production. In this article, we analyze the potential of fog water collection in two sites (Alto Patache and Falda Verde) distant by about 1000 km within the Atacama Desert. Additionally, in both locations, the environmental conditions within greenhouse structures, the potential energy requirement for environmental conditioning (including the energy production from photovoltaic panels) and the water requirements of vegetable crops under greenhouse conditions were modeled. The annual average of fog water collection registered was 2.9 and 3.3 L per day per m2 in Alto Patache and Falda Verde, respectively. During the most demanding season for crop evapotranspiration, 2.13 m2 of fog collectors can supply the water required for 1 m2 of greenhouse crops. The energy required for water and air pumps in the hydroponic systems can be supplied with photovoltaic systems including eight PV modules and a battery storage capacity of 9.4 kWh. In conclusion, the present study sheds light on the possibilities of massive water collection from fog to be used in local and sustainable food production in the Atacama Desert.

The fossil distribution of two pelagic lamniform sharks Alopias vulpinus and Lamna nasus, from South America

ABSTRACT The fossil record of the southeastern Pacific Ocean has been scarcely studied compared to other regions. We present the detailed description of two pelagic shark species, Alopias vulpinus (common thresher) and Lamna nasus (porbeagle) (Elasmobranchii: Lamniformes), from the Neogene of South America. The fossil teeth described here were recovered from the Bahia Inglesa Formation in Caldera, northern Chile. Our study provides the first comprehensive descriptions of fossil remains of A. vulpinus from Chile and L. nasus from the Americas. The occurrence of the common thresher shark represents the first published record and description of a representative from the family Alopiidae in northern Chile, whereas the fossil remains of the porbeagle shark are recorded for the first time in Chile. This study contributes to the understanding of the past distribution of shark species in the Eastern Pacific of South America during the Neogene period. It further confirms the particular abundance of lamniform sharks in the Neogene of Chile.

Evaluating the contribution of hydrothermal fluids and clay minerals to the enrichment of rare earth elements and yttrium (REY) in deep-sea sediments

Deep-sea REY-rich sediments have attracted considerable attention in recent studies because of their extremely high REY resource potential. Previous studies highlighted that hydrothermal precipitates (e.g., Fe-Mn (oxyhydr)oxides) have played an important role in REY enrichment in deep-sea sediments by scavenging REY from seawater. However, the exact extent of the contribution of hydrothermal scavenging to the REY accumulation has not yet been evaluated. In addition, REY enrichment generally occurred in the pelagic clays, and whether the clays have played a role in the REY accumulation is poorly constrained. We studied bulk-sediment geochemistry and mineral fractions of sediments from two sites in the Eastern South Pacific Ocean. The results show that both cores contain REY-rich sediments layers possessing average ΣREY contents of 989 ppm and 1563 ppm, respectively. The calculated REY resource amounts in the 1 km × 1 km × optimal recovery depth (m) of the two sites are summed to 4690 t-REO. Carbonate compensation depth is one of the factors controlling the REY contents in the sediments in our study area. The shale-normalized REY patterns and calculated simulation results suggest that direct input of REY from the hydrothermal sources to the sediments was not significant. The evaluation of the contributions of REY scavenged by hydrothermal Fe-Mn (oxyhydr)oxides suggests that for the metalliferous sediments in which Fe-Mn (oxyhydr)oxides are hydrothermal-dominated, the Fe2O3 and ΣREY contents show a pronounced positive correlation for all cores, implying hydrothermal scavenging of REY significantly contributed to the accumulation of REY. However, with the continuous addition of hydrothermal Fe-Mn (oxyhydr)oxides in the pelagic clay sediments, the ΣREY contents in the REY-rich sediments firstly exhibited an increase, and then when the total Fe2O3 components achieved a certain value (∼25 wt% in this study) they started to decline. This finding suggests the appropriate input of hydrothermal Fe-Mn (oxyhydr)oxides into the sediments certainly increases the ΣREY contents through a scavenging mechanism, but that excessive addition of them would, in turn, decrease the ΣREY contents of the sediments. Additionally, the amount of clay minerals exhibited a significant positive correlation with ΣREY contents, therefore, we inferred that clay minerals probably played an important role in REY accumulation in the sediments.