Although pesticides are frequently used for agriculture in the Galapagos Islands (Ecuador), there are, to date, no investigations of pesticide occurrences in its coastal waters. We examined the ...presence of pesticide residues in the coastal waters of urban areas in two islands of the Galapagos archipelago using a repeated sampling design. Quantification was performed by solid-phase extraction, followed by chemical analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-electron capture detector (GC-ECD). The diversity and concentration of pesticide residues in Santa Cruz island were higher compared to Isabela island. In total, sixteen pesticides were detected, including three persistent organic pollutants. Carbendazim (23.93 μg·L−1), cadusafos (4.74 μg·L−1), DDT (2.99 μg·L−1), diuron (1.61 μg·L−1) and aldrin (1.55 μg·L−1) were detected with the highest concentrations between samples. Repetitions in locations show that concentrations of pesticide residues varied considerably in space and time. Comparison with local products indicated agricultural activities on the islands as a possible source. Furthermore, evaluation through ecological risk quotients showed that the observed concentration levels of seven pesticides pose a relatively high risk for three biotic groups (i.e. algae, invertebrates and fishes). Taken together, this study provides insights into the need to regulate, monitor and assess the presence of pesticides in the islands. At a global scale, this study is moreover valuable for the many islands that are facing the same challenges.
Display omitted
•Pesticides occurrence was evaluated in coastal urban areas of Galapagos archipelago.•Sixteen pesticides were detected including three persistent organic pollutants.•Source of pesticides was associated with agriculture production in the islands.•Pesticide residues concentration varied considerably in space and time.
The origin of volatiles on Earth is still a matter of debate. Noble gases are an efficient geochemical tool to constrain Earth formation processes due to their inertness. Several studies have focused ...on the neon isotopic composition of the lower mantle because the 20Ne/22Ne ratio is thought to reflect that of Earth's primordial components. Two models to explain the origin of light noble gases on Earth have been proposed: either solar wind implantation onto the Earth's solid precursors or dissolution into the mantle of a primordial atmosphere captured from solar nebula gas. In order to test these two models, we analyzed the noble gas compositions (helium, neon and argon) of two submarine oceanic island basalt glasses from Fernandina volcano (Galápagos archipelago), which have among the most primitive/unradiogenic terrestrial helium and neon isotopic compositions. Several sample pieces are studied both by step-crushing and by laser ablation analyses of single vesicles. Results of step-crushing are consistent with those of laser ablation analyses, but the latter results provide new insights into the origin of atmospheric contamination. The single-vesicle laser-ablation measurements overlap with the step crushing results, but have systematically higher 40Ar/36Ar, and 3He/36Ar, suggesting less atmospheric contamination using this method. The single vesicle data therefore suggest that atmospheric contamination is introduced by exposure to the modern atmosphere, after sample collection. 3He/4He values are about 23 times the atmospheric ratio (R/Ra) for the two Fernandina (Galápagos) samples, in agreement with previous studies. We obtain 20Ne/22Ne and 40Ar/36Ar isotopic ratios as high as 12.91 and 9400, respectively, for the mantle source of the Galápagos hotspot. The new data show that step-crushing and laser ablation analyses are complementary methods that should be used together to derive the noble gas ratios in uncontaminated samples. The results of neon compositions are consistent with previous hotspot studies and support the model of solar wind implantation associated with sputtering to explain helium and neon origins on Earth.
•Step-crushing and laser ablation are complementary methods to extract noble gases.•Laser ablation noble gas analyses are almost free of atmospheric contamination.•The 20Ne/22Ne ratio is close to the Neon B composition for the Galápagos source.•The model of solar wind irradiation explains the neon origin on Earth.
In 2000, longline fishing was banned inside the Galapagos Marine Reserve to prevent illegal fishing of sharks and bycatch of endangered, threatened, and protected (ETP) species. Despite local ...management institutions possess one of the most sophisticated control and surveillance systems in the Eastern Tropical Central Pacific, statistical and anecdotic evidence suggest the longline ban has been ineffective in eradicating illegal, unreported and unregulated (IUU) fishing for the last two decades. This short communication examines the legal, institutional, and socio-economic factors that have prevented the effective implementation of the longline ban and proposes an ecosystem approach to fisheries to maintain bycatch mortality rates below biologically based limits, facilitating the recovery of ETP species while safeguarding a sustainable development of the Galapagos small-scale tuna fishery. Significant investments in science, technology, and innovation are necessary to encourage gradual and adaptive improvements in fishing practices to reduce IUU fishing and bycatch.
New satellite missions (e.g., the European Space Agency's Sentinel‐1 constellation), advances in data downlinking, and rapid product generation now provide us with the ability to access ...space‐geodetic data within hours of their acquisition. To truly take advantage of this opportunity, we need to be able to interpret geodetic data in a prompt and robust manner. Here we present a Bayesian approach for the inversion of multiple geodetic data sets that allows a rapid characterization of posterior probability density functions (PDFs) of source model parameters. The inversion algorithm efficiently samples posterior PDFs through a Markov chain Monte Carlo method, incorporating the Metropolis‐Hastings algorithm, with automatic step size selection. We apply our approach to synthetic geodetic data simulating deformation of magmatic origin and demonstrate its ability to retrieve known source parameters. We also apply the inversion algorithm to interferometric synthetic aperture radar data measuring co‐seismic displacements for a thrust‐faulting earthquake (2015 Mw 6.4 Pishan earthquake, China) and retrieve optimal source parameters and associated uncertainties. Given its robustness and rapidity in estimating deformation source parameters and uncertainties, our Bayesian framework is capable of taking advantage of real‐time geodetic measurements. Thus, our approach can be applied to geodetic data to study magmatic, tectonic, and other geophysical processes, especially in rapid‐response operational settings (e.g., volcano observatories). Our algorithm is fully implemented in a MATLAB®‐based software package (Geodetic Bayesian Inversion Software) that we make freely available to the scientific community.
Key Points
We present a Bayesian approach for the inversion of geodetic data and demonstrate successful applications to synthetic and real data
Our approach allows rapid estimates of source parameters and uncertainties and is well suited for rapid‐response and operational settings
We have implemented our approach in a MATLAB®‐based software package (GBIS) that is made freely available to the scientific community
•Particle size and soil organic carbon decreased with increasing weathering duration.•Al and Fe accumulated in older, highly weathered soils while base cations decreased.•Andic properties were ...expressed in the youngest soils studied.•Andic properties increased with elevation / moisture.
The flora and fauna of the Galápagos Islands have long been subject to scientific inquiry, but the soils have remained largely ignored until recently. The objective of this study was to assess the differences in main soil characteristics and nutrient reserves within and among the agricultural zones of islands Isabela, Santa Cruz and San Cristóbal to provide background information for informed agricultural decision making and a baseline against which future changes may be assessed. Aqua regia-extractable Al and Fe showed a general trend of accumulation with island age and increasing moisture levels within the agricultural zone, while base cations Ca, K, Mg and Na tended to decrease along the same gradients, with some variation likely due to agricultural inputs. Concentrations of silicon, aluminum and iron associated with amorphous constituents (Sio, Alo, Feo) tended to decrease with island age while iron in crystalline and non-crystalline hydrous oxides (Fed) showed a slight increase. Aluminum and iron in non-crystalline and organic complexes were more abundant in areas with higher precipitation. Electrical conductivity, pH in water, pH in sodium fluoride, phosphate retention, organic carbon content and particle size tended to decrease with island age while bulk density increased. Andic properties were expressed in all the soils of the youngest island studied, Isabela, and in higher-elevation soils of the intermediate-age Santa Cruz Island, while the soils of the oldest island studied, San Cristóbal, did not show andic properties and were dominated by crystalline clays and iron oxides. The wide range of soil development across the three islands requires soil management recommendations be tailored to each island and even within each island to ensure appropriate stewardship of this important natural resource.
Reduction of functional diversity (FD) and phylogenetic diversity (PD) likely affects ecosystem functions and reduces the potential of communities to respond to changes, such as climate change. ...Mutualistic interactions are essential for maintaining diversity, but their role has largely been ignored in conservation planning. We propose using a species' interaction niche – the diversity of its interaction partners – to measure a species' contribution to the maintenance of FD and PD via mutualistic interactions, and thus identify species and interspecific interactions that are particularly important for the conservation of ecosystem functions and evolutionary lineages in ecological communities. Our approach represents a switch in perspective that allows a direct assessment of the importance of mutualistic interactions for the maintenance of biodiversity and ecosystem functioning.
Species interactions are key for maintaining biodiversity and the functioning of ecological communities.Despite the importance of species interactions for ecological communities, there is currently no method to quantify the contribution of individual species to maintaining functional diversity (FD) and phylogenetic diversity (PD) via their interactions with other species.Species' interaction niches – the FD and PD of their interaction partners – measure the contribution of mutualists to conserving ecosystem functions and evolutionary lineages, respectively.Measuring the contribution of species to maintaining FD and PD via their mutualistic interactions will guide conservation efforts and facilitate new studies on the evolution of ecological communities.
The Galápagos archipelago, a chain of islands formed by hotspot-induced volcanism on the Nazca tectonic plate, exhibits pronounced gradients of rock age and climate. Here, we investigate chemical ...weathering along a soil chronosequence (1.5 to 1070 ka) and under humid vs. dry conditions. Our results show considerable loss of base cations already in the early to intermediate phases of weathering under humid conditions (e.g. 95 % of Na and 78 % of Mg lost from the topsoil after 26 ka) and almost complete loss from the entire profile in soils older than 800 ka. Depletion of Si was less pronounced, with topsoil losses of 24 % and 63–68 % after 26 ka and >800 ka, respectively. Under dry conditions, weathering rates were much lower, e.g. 33 % of Na and 1.4 % of Mg lost from the topsoil after 26 ka. Indices of chemical weathering, e.g. the Chemical Index of Alteration and the Ruxton Ratio, correlated well with indicators of pedogenic development, such as solum thickness, soil pH, or the ratio of oxalate- to dithionite-extractable Fe. Total weathering flux and associated CO2 consumption rates estimated from profile-scale element losses in this study exceeded catchment-scale estimates reported for other volcanic islands or global averages during the early weathering phase, but were much lower in the intermediate and late phases. Nevertheless, total C drawdown was dominated by soil organic C sequestration (70–90 % share) rather than inorganic, weathering-induced CO2 consumption during early pedogenesis (≤4.3 ka), and the relative importance switched in the intermediate and late phases (90–95 % share of weathering-induced C drawdown at ≥166 ka). Dust deposition derived from a nearby ocean sediment core was <20 % of total basalt mass loss at the young and intermediate-aged sites, but reached 40–60 % at the older sites (>800 ka). Our results suggest that (1) young volcanic surfaces are very efficient (inorganic and organic) C sinks, (2) the development of thick soil covers at advanced pedogenic stages effectively shields the underlying rocks and decelerates weathering, and (3) dust inputs become an increasingly important biogeochemical factor in such highly weathered environments.
Thirteen species of deep-water calcaxonian octocorals belonging to the families Primnoidae, Chrysogorgiidae, and Isididae collected from off the Galápagos and Cocos Islands are described and figured. ...Seven of these species are described as new; nine of the 13 are not known outside the Galápagos region. Of the four species occurring elsewhere, two also occur in the eastern Pacific, one off Hawaii, and one from off Antarctica. A key to the 22 Indo-Pacific species of
is provided to help distinguish those species.
Geophysical analysis of the Earth's lower mantle has revealed the presence of two superstructures characterized by low shear wave velocities on the core‐mantle boundary. These Large Low Shear ...Velocity Provinces (LLSVPs) play a crucial role in the dynamics of the lower mantle and act as the source region for deep‐seated mantle plumes. However, their origin, and the characteristics of the surrounding deep mantle, remain enigmatic. Mantle plumes located above the margins of the LLSVPs display evidence for the presence of this deep‐seated, thermally and/or chemically heterogeneous mantle material ascending into the melting region. As a result, analysis of the spatial geochemical heterogeneity in ocean island basalts provides constraints on the structure of the Earth's lower mantle and the origin of the LLSVPs. In this study, we focus on the Galápagos Archipelago in the eastern Pacific, where bilateral asymmetry in the radiogenic isotopic composition of erupted basalts has been linked to the presence of LLSVP material in the underlying plume. We show, using spatial variations in the major element contents of high‐MgO basalts, that the isotopically enriched south‐western region of the Galápagos mantle—assigned to melting of LLSVP material—displays no evidence for lithological heterogeneity in the mantle source. As such, it is unlikely that the Pacific LLSVP represents a pile of subducted oceanic crust. Clear evidence for a lithologically heterogeneous mantle source is, however, found in the north‐central Galápagos, indicating that a recycled crustal component is present near the eastern margin of the Pacific LLSVP, consistent with seismic observations.
Plain Language Summary
The Earth's lowermost mantle is characterized by the presence of two superstructures known as the Large Low Shear Velocity Provinces, or LLSVPs. These bodies are characterized by anomalously slow seismic shear wave velocities, may be denser than their surroundings, and play an important role in mantle dynamics. However, the origin of these deep mantle structures remains unclear. In this study, we use geochemical data from the Galápagos Archipelago, formed by melting within an upwelling mantle plume containing LLSVP material, to demonstrate that the Pacific LLSVP is not composed of subducted oceanic crust which has accumulated on the core‐mantle boundary (as has previously been hypothesized).
Key Points
Compositional variability in erupted basalts and olivine crystals reveals the spatial distribution of recycled material in the Galápagos plume
The eastern Pacific Large Low Shear Velocity Province (LLSVP) does not represent piles of subducted oceanic crust
Geochemical and geophysical data indicate the presence of recycled crustal material near the eastern margin of the Pacific LLSVP
Renewable energy technologies may have positive socioeconomic and environmental consequences at the local, regional, and global levels. However, transitioning to renewable energy sources requires ...substantial capital investments, which calls for alternative funding mechanisms, particularly in developing areas. In this study, we used the contingent valuation method to assess the economic feasibility of voluntary contributions from tourists to fund renewable energy projects in the Galápagos Islands, a renowned tourist destination. Of the 336 tourists who completed our survey, 42.3 % were willing to donate. Estimation results based on logit models indicate that the likelihood of giving is inversely related to the donation amount and positively related to the perceived consequentiality of our study and the tourists' familiarity with renewable energy. Conservative estimates indicate that the median tourist would make a one-time donation of US$ 85 to finance the transition to renewable energy. We conclude that voluntary donations from tourists can accelerate the transition to renewable energy and thus help the Galápagos Islands reach their goal of decarbonizing the islands by 2030.
•Developing areas need alternative sources to fund renewable energy projects.•Contingent valuation is applied to elicit tourists' willingness to donate.•Tourists are willing to donate to local renewable energy projects.
PDF
