Science.gov

Sample records for galapagos petrel pterodroma

  1. Range expansion and hybridization in Round Island petrels (Pterodroma spp.): evidence from microsatellite genotypes.

    PubMed

    Brown, Ruth M; Nichols, Richard A; Faulkes, Chris G; Jones, Carl G; Bugoni, Leandro; Tatayah, Vikash; Gottelli, Dada; Jordan, William C

    2010-08-01

    Historical records suggest that the petrels of Round Island (near Mauritius, Indian Ocean) represent a recent, long-distance colonization by species originating from the Atlantic and Pacific Oceans. The majority of petrels on Round Island appear most similar to Pterodroma arminjoniana, a species whose only other breeding locality is Trindade Island in the South Atlantic. Using nine microsatellite loci, patterns of genetic differentiation in petrels from Round and Trindade Islands were analysed. The two populations exhibit low but significant levels of differentiation in allele frequencies and estimates of migration rate between islands using genetic data are also low, supporting the hypothesis that these populations have recently separated but are now isolated from one another. A second population of petrels, most similar in appearance to the Pacific species P. neglecta, is also present on Round Island and observations suggest that the two petrel species are hybridizing. Vocalizations recorded on the island also suggest that hybrid birds may be present within the population. Data from microsatellite genotypes support this hypothesis and indicate that there may have been many generations of hybridization and back-crossing between P. arminjoniana and P. neglecta on Round Island. Our results provide an insight into the processes of dispersal and the consequences of secondary contact in Procellariiformes. PMID:20618891

  2. Using PCR-RFLP for sexing of the endangered Galápagos petrel (Pterodroma phaeopygia).

    PubMed

    Patiño, L; Cruz, M; Martínez, P; Cedeño-Escobar, V

    2013-01-01

    Pterodroma phaeopygia is a critically endangered avian species of the Galápagos Islands. This bird is sexually monomorphic, making it difficult to identify the sex. This information, however, is relevant to studies of behavior, ecology, and management of wild or captive populations. Here, we aimed to implement a molecular approach for determining sex in this petrel. DNA was extracted from the blood and the feathers of 24 adult P. phaeopygia, with samples from a female and a male Gallus gallus for comparison. We amplified the cromo-helicase DNA binding protein 1 (CHD-1) gene by PCR, using primers P2 and P8. Allele CHD-1W is unique to females and CHD-1Z occurs in both sexes. We then digested these PCR products using the restriction enzyme HaeIII. The PCR amplified a 400-bp product for both alleles. The digestion of the G. gallus, amplicons split the CHD-1Z allele into two fragments (of 320 and 80 bp), while CHD-1W remained intact. Thus, the male exhibited two bands (digested CHD- 1Z) and the female three bands (undigested CHD-1W and digested CHD-1Z). Applying this RFLP method on DNA derived from blood, 9 of the 24 petrels were found to be male, while 15 were females. The same results were obtained using feathers as the source of DNA. To our knowledge, this is the first report of molecular method for sexing this species. The potential of sexing this petrel from feathers is remarkable as it minimizes blood sampling induced stress. This method could be used to reinforce the conservation efforts for this bird, to investigate population sex ratios and to develop new conservation strategies. PMID:24222251

  3. Feeding Habits of Introduced Black Rats, Rattus rattus, in Nesting Colonies of Galapagos Petrel on San Cristóbal Island, Galapagos.

    PubMed

    Riofrío-Lazo, Marjorie; Páez-Rosas, Diego

    2015-01-01

    Introduced rodents are responsible for ecosystem changes in islands around the world. In the Galapagos archipelago, their effects on the native flora and fauna are adverse, including the extinction of endemic rodents in some islands and the reduction in the reproductive success of the Galapagos petrel (Pterodroma phaeopygia) in its nesting zones. Understanding the feeding behavior of introduced rodents and their trophic interactions with native and non-native species on islands, can assist in the design of management strategies and conservation plans of invasive and endemic species respectively. Four petrel nesting colonies were monitored during June 2013 on San Cristóbal Island (El Plátano, El Junco, San Joaquín, and La Comuna). The feeding habits of black rats were evaluated by analyzing stomach contents and stable isotopes in hair. Three species of introduced rodents were captured. R. rattus was the most abundant at all sites (n=43, capture success (CS) = 55.8%), followed by the house mouse, Mus musculus (n = 17, CS = 37.8%), and the Norwegian rat, R. norvegicus (n = 4, CS = 4.5%), captured only at La Comuna. The omnivorous black rat ate mostly plants (98%) and arthropods (2%). Intact seeds of Miconia robinsoniana were the main food at all sites (relative abundance=72.1%, present in 95% of the analyzed stomachs), showing the black rats' possible role in the archipelago as endemic seed dispersers. There was no evidence of petrel's intake; however, its possible consumption is not discarded at all. The δ15N and δ13C analysis corroborated the primarily herbivorous diet of black rats. The isotopic signatures of the three rodent species reflect the inter- and intra-specific differential use of food resources. Black rat showed a wider diet in La Comuna, which was related to a lower availability of its primary prey and its ability to adapt to the available resources in its habitat. PMID:25984724

  4. Feeding Habits of Introduced Black Rats, Rattus rattus, in Nesting Colonies of Galapagos Petrel on San Cristóbal Island, Galapagos

    PubMed Central

    Riofrío-Lazo, Marjorie; Páez-Rosas, Diego

    2015-01-01

    Introduced rodents are responsible for ecosystem changes in islands around the world. In the Galapagos archipelago, their effects on the native flora and fauna are adverse, including the extinction of endemic rodents in some islands and the reduction in the reproductive success of the Galapagos petrel (Pterodroma phaeopygia) in its nesting zones. Understanding the feeding behavior of introduced rodents and their trophic interactions with native and non-native species on islands, can assist in the design of management strategies and conservation plans of invasive and endemic species respectively. Four petrel nesting colonies were monitored during June 2013 on San Cristóbal Island (El Plátano, El Junco, San Joaquín, and La Comuna). The feeding habits of black rats were evaluated by analyzing stomach contents and stable isotopes in hair. Three species of introduced rodents were captured. R. rattus was the most abundant at all sites (n=43, capture success (CS) = 55.8%), followed by the house mouse, Mus musculus (n = 17, CS = 37.8%), and the Norwegian rat, R. norvegicus (n = 4, CS = 4.5%), captured only at La Comuna. The omnivorous black rat ate mostly plants (98%) and arthropods (2%). Intact seeds of Miconia robinsoniana were the main food at all sites (relative abundance=72.1%, present in 95% of the analyzed stomachs), showing the black rats’ possible role in the archipelago as endemic seed dispersers. There was no evidence of petrel’s intake; however, its possible consumption is not discarded at all. The δ15N and δ13C analysis corroborated the primarily herbivorous diet of black rats. The isotopic signatures of the three rodent species reflect the inter- and intra-specific differential use of food resources. Black rat showed a wider diet in La Comuna, which was related to a lower availability of its primary prey and its ability to adapt to the available resources in its habitat. PMID:25984724

  5. At-sea distribution of satellite-tracked grey-faced petrels, Pterodroma macroptera gouldi, captured on the Ruamaahua (Aldermen) Islands, New Zealand

    USGS Publications Warehouse

    MacLeod, Catriona; Adams, Josh; Lyver, Phil

    2008-01-01

    We used satellite telemetry to determine the at-sea distribution of 32 adult (non-breeders and failed breeders) Grey-faced Petrels, Pterodroma macroptera gouldi, during July-October in 2006 and 2007. Adults captured at breeding colonies on the Ruamaahua (Aldermen) Islands ranged across the southwestern Pacific Ocean and Tasman Sea between 20-49°S and 142°E and 1300 W Petrels were located almost exclusively over offshore waters> 1000 m depth. The extent oftheir distributions was similar across years, but petrels ranged farther south and west in 2006. Individuals displayed a high degree ofspatial overlap (48-620/0 among individuals) and area use revealed three general "hotspots" within their overall range: waters near the Ruamaahua Islands; the central Tasman Sea; and the area surrounding the Chatham Rise. In July-August 2006, most petrels congregated over the Tasman Sea, but for the same period in 2007 were predominantly associated with Chatham Rise. The home ranges of petrels tended to overlap disproportionately more than expected with the Australian Exclusive Economic Zone and less than expected with High Seas, relative to the area available in each zone, in July-August 2006. Accordingly, multiple nations are responsible for determining potential impacts resulting from fisheries bycatch and potential resource competition with Grey-faced Petrels.

  6. Non-precocial grey-faced petrel chicks (Pterodroma macroptera gouldi) show no age-related variation in corticosterone responses to capture and handling.

    PubMed

    Adams, N J; Cockrem, J F; Candy, E J; Taylor, G A

    2008-05-15

    Development patterns in birds range from precocial species, which hatch chicks largely capable of independent existence, to altricial species, chicks of which are highly dependent on their parents for extended periods. Previous work indicates precocial chicks have a robust corticosterone response from hatching whereas non-precocial and altricial chicks have a small response that increases through development. Grey-faced petrels are characteristic of most burrowing procellariiform seabirds with non-precocial chicks that are unable to locomote and are dependent on adults for food, although chicks have well developed downy plumage and can thermoregulate at or soon after hatching. Initial plasma corticosterone concentrations and corticosterone responses to handling were measured during development in semi-precocial grey-faced petrel (Pterodroma macroptera gouldi) chicks to determine whether they showed a precocial or altricial corticosterone response pattern. Chicks were sampled at six intervals through development from shortly after hatching until close to fledging. Mean corticosterone responses to handling after 30 min were high (115.9+/-10.7 ng/ml) from 2 to 4d after hatching and remained high throughout development (70-110 ng/ml). Contrary to expectations for non-precocial chicks, this pattern of corticosterone responses to handling indicates that grey-faced petrel chicks are able to perceive and respond to potential stressors from hatching, a response previously only demonstrated for precocial birds. PMID:18472100

  7. Ingested plastic as a route for trace metals in Laysan Albatross (Phoebastria immutabilis) and Bonin Petrel (Pterodroma hypoleuca) from Midway Atoll.

    PubMed

    Lavers, Jennifer L; Bond, Alexander L

    2016-09-15

    Seabirds are declining faster than any other group of birds, with plastic ingestion and associated contaminants linked to negative impacts on marine wildlife, including >170 seabird species. To provide quantitative data on the effects of plastic pollution, we sampled feathers and stomach contents from Laysan Albatross (Phoebastria immutabilis) and Bonin Petrel (Pterodroma hypoleuca) on Midway Atoll, North Pacific Ocean, and assessed our ability to detect change over time by synthesizing previous studies. Between 25 and 100% of fledglings exceed international targets for plastic ingestion by seabirds. High levels of ingested plastic were correlated with increased concentrations of chlorine, iron, lead, manganese, and rubidium in feathers. The frequency of plastic ingestion by Laysan Albatross and concentration of some elements in both species is increasing, suggesting deterioration in the health of the marine environment. Variability in the frequency of plastic ingestion by Laysan Albatross may limit their utility as an indicator species. PMID:27339745

  8. Differentiation of sympatric populations of the band-rumped storm-petrel in the Galapagos Islands: an examination of genetics, morphology, and vocalizations.

    PubMed

    Smith, A L; Friesen, V L

    2007-04-01

    In each of at least two locations within the Galapagos Islands, breeding band-rumped storm-petrels (Oceanodroma castro) form two distinct populations that use the same colony site at separate times of the year for reproduction. Temporal segregation of these populations raises the possibility that they are reproductively isolated and represent cryptic species. We examined variation in mitochondrial DNA, morphology, and vocalizations of storm-petrel populations nesting 6 months apart on the islet of Plaza Norte in the Galapagos. Seasonal populations displayed low but significant levels of differentiation in the mitochondrial control region, five morphological variables, and one feature of male vocalizations. Breeding populations appear to have been separated for approximately 1700 years. Given the recent divergence date and relatively high effective population sizes (4000-5600 females each), seasonal populations are unlikely to be in genetic equilibrium. As a result, the low divergence estimate probably reflects historical association and not contemporary genetic exchange. These populations are not sufficiently differentiated to be considered cryptic species. However, they are probably in the early stages of divergence. Consequently, we recommend that cool- and hot season populations on Plaza Norte be recognized as separate management units. PMID:17402976

  9. Mitochondrial and nuclear DNA sequences reveal recent divergence in morphologically indistinguishable petrels.

    PubMed

    Welch, Andreanna J; Yoshida, Allison A; Fleischer, Robert C

    2011-04-01

    Often during the process of divergence, genetic markers will only gradually obtain the signal of isolation. Studies of recently diverged taxa utilizing both mitochondrial and nuclear data sets may therefore yield gene trees with differing levels of phylogenetic signal as a result of differences in coalescence times. However, several factors can lead to this same pattern, and it is important to distinguish between them to gain a better understanding of the process of divergence and the factors driving it. Here, we employ three nuclear intron loci in addition to the mitochondrial Cytochrome b gene to investigate the magnitude and timing of divergence between two endangered and nearly indistinguishable petrel taxa: the Galapagos (GAPE) and Hawaiian (HAPE) petrels (Pterodroma phaeopygia and P. sandwichensis). Phylogenetic analyses indicated reciprocal monophyly between these two taxa for the mitochondrial data set, but trees derived from the nuclear introns were unresolved. Coalescent analyses revealed effectively no migration between GAPE and HAPE over the last 100,000 generations and that they diverged relatively recently, approximately 550,000 years ago, coincident with a time of intense ecological change in both the Galapagos and Hawaiian archipelagoes. This indicates that recent divergence and incomplete lineage sorting are causing the difference in the strength of the phylogenetic signal of each data set, instead of insufficient variability or ongoing male-biased dispersal. Further coalescent analyses show that gene flow is low even between islands within each archipelago suggesting that divergence may be continuing at a local scale. Accurately identifying recently isolated taxa is becoming increasingly important as many clearly recognizable species are already threatened by extinction. PMID:21324012

  10. Mitochondrial and nuclear DNA sequences reveal recent divergence in morphologically indistinguishable petrels.

    PubMed

    Welch, Andreanna J; Yoshida, Allison A; Fleischer, Robert C

    2011-04-01

    Often during the process of divergence, genetic markers will only gradually obtain the signal of isolation. Studies of recently diverged taxa utilizing both mitochondrial and nuclear data sets may therefore yield gene trees with differing levels of phylogenetic signal as a result of differences in coalescence times. However, several factors can lead to this same pattern, and it is important to distinguish between them to gain a better understanding of the process of divergence and the factors driving it. Here, we employ three nuclear intron loci in addition to the mitochondrial Cytochrome b gene to investigate the magnitude and timing of divergence between two endangered and nearly indistinguishable petrel taxa: the Galapagos (GAPE) and Hawaiian (HAPE) petrels (Pterodroma phaeopygia and P. sandwichensis). Phylogenetic analyses indicated reciprocal monophyly between these two taxa for the mitochondrial data set, but trees derived from the nuclear introns were unresolved. Coalescent analyses revealed effectively no migration between GAPE and HAPE over the last 100,000 generations and that they diverged relatively recently, approximately 550,000 years ago, coincident with a time of intense ecological change in both the Galapagos and Hawaiian archipelagoes. This indicates that recent divergence and incomplete lineage sorting are causing the difference in the strength of the phylogenetic signal of each data set, instead of insufficient variability or ongoing male-biased dispersal. Further coalescent analyses show that gene flow is low even between islands within each archipelago suggesting that divergence may be continuing at a local scale. Accurately identifying recently isolated taxa is becoming increasingly important as many clearly recognizable species are already threatened by extinction.

  11. Molecular evidence for the identity of the Magenta petrel.

    PubMed

    Lawrence, Hayley A; Millar, Craig D; Imber, Michael J; Crockett, David E; Robins, Judith H; Scofield, R Paul; Taylor, Graeme A; Lambert, David M

    2009-03-01

    A lone petrel was shot from the decks of an Italian warship (the 'Magenta') while it was sailing the South Pacific Ocean in 1867, far from land. The species, unknown to science, was named the 'Magenta petrel' (Procellariiformes, Procellariidae, Pterodroma magentae). No other specimens of this bird were collected and the species it represented remained a complete enigma for over 100 years. We compared DNA sequence of the mitochondrial cytochrome b gene from the Magenta petrel to that of other petrels using phylogenetic methods and ancient DNA techniques. Our results strongly suggest that the Magenta petrel specimen is a Chatham Island taiko. Furthermore, given the collection location of the Magenta petrel, our finding indicates that the Chatham Island taiko forages far into the Pacific Ocean (near South America). This has implications for the conservation of the taiko, one of the world's rarest seabirds. PMID:21564674

  12. Global spatial ecology of three closely-related gadfly petrels.

    PubMed

    Ramos, Raül; Ramírez, Iván; Paiva, Vitor H; Militão, Teresa; Biscoito, Manuel; Menezes, Dília; Phillips, Richard A; Zino, Francis; González-Solís, Jacob

    2016-01-01

    The conservation status and taxonomy of the three gadfly petrels that breed in Macaronesia is still discussed partly due to the scarce information on their spatial ecology. Using geolocator and capture-mark-recapture data, we examined phenology, natal philopatry and breeding-site fidelity, year-round distribution, habitat usage and at-sea activity of the three closely-related gadfly petrels that breed in Macaronesia: Zino's petrel Pterodroma madeira, Desertas petrel P. deserta and Cape Verde petrel P. feae. All P. feae remained around the breeding area during their non-breeding season, whereas P. madeira and P. deserta dispersed far from their colony, migrating either to the Cape Verde region, further south to equatorial waters in the central Atlantic, or to the Brazil Current. The three taxa displayed a clear allochrony in timing of breeding. Habitat modelling and at-sea activity patterns highlighted similar environmental preferences and foraging behaviours of the three taxa. Finally, no chick or adult was recaptured away from its natal site and survival estimates were relatively high at all study sites, indicating strong philopatry and breeding-site fidelity for the three taxa. The combination of high philopatry, marked breeding asynchrony and substantial spatio-temporal segregation of their year-round distribution suggest very limited gene flow among the three taxa. PMID:27001141

  13. Global spatial ecology of three closely-related gadfly petrels

    PubMed Central

    Ramos, Raül; Ramírez, Iván; Paiva, Vitor H.; Militão, Teresa; Biscoito, Manuel; Menezes, Dília; Phillips, Richard A.; Zino, Francis; González-Solís, Jacob

    2016-01-01

    The conservation status and taxonomy of the three gadfly petrels that breed in Macaronesia is still discussed partly due to the scarce information on their spatial ecology. Using geolocator and capture-mark-recapture data, we examined phenology, natal philopatry and breeding-site fidelity, year-round distribution, habitat usage and at-sea activity of the three closely-related gadfly petrels that breed in Macaronesia: Zino’s petrel Pterodroma madeira, Desertas petrel P. deserta and Cape Verde petrel P. feae. All P. feae remained around the breeding area during their non-breeding season, whereas P. madeira and P. deserta dispersed far from their colony, migrating either to the Cape Verde region, further south to equatorial waters in the central Atlantic, or to the Brazil Current. The three taxa displayed a clear allochrony in timing of breeding. Habitat modelling and at-sea activity patterns highlighted similar environmental preferences and foraging behaviours of the three taxa. Finally, no chick or adult was recaptured away from its natal site and survival estimates were relatively high at all study sites, indicating strong philopatry and breeding-site fidelity for the three taxa. The combination of high philopatry, marked breeding asynchrony and substantial spatio-temporal segregation of their year-round distribution suggest very limited gene flow among the three taxa. PMID:27001141

  14. Global spatial ecology of three closely-related gadfly petrels

    NASA Astrophysics Data System (ADS)

    Ramos, Raül; Ramírez, Iván; Paiva, Vitor H.; Militão, Teresa; Biscoito, Manuel; Menezes, Dília; Phillips, Richard A.; Zino, Francis; González-Solís, Jacob

    2016-03-01

    The conservation status and taxonomy of the three gadfly petrels that breed in Macaronesia is still discussed partly due to the scarce information on their spatial ecology. Using geolocator and capture-mark-recapture data, we examined phenology, natal philopatry and breeding-site fidelity, year-round distribution, habitat usage and at-sea activity of the three closely-related gadfly petrels that breed in Macaronesia: Zino’s petrel Pterodroma madeira, Desertas petrel P. deserta and Cape Verde petrel P. feae. All P. feae remained around the breeding area during their non-breeding season, whereas P. madeira and P. deserta dispersed far from their colony, migrating either to the Cape Verde region, further south to equatorial waters in the central Atlantic, or to the Brazil Current. The three taxa displayed a clear allochrony in timing of breeding. Habitat modelling and at-sea activity patterns highlighted similar environmental preferences and foraging behaviours of the three taxa. Finally, no chick or adult was recaptured away from its natal site and survival estimates were relatively high at all study sites, indicating strong philopatry and breeding-site fidelity for the three taxa. The combination of high philopatry, marked breeding asynchrony and substantial spatio-temporal segregation of their year-round distribution suggest very limited gene flow among the three taxa.

  15. The Galapagos.

    ERIC Educational Resources Information Center

    Schiller, Nancy A.; Herreid, Clyde F.

    2000-01-01

    Uses a problem-based teaching approach to teach about the geological origins of the Galapagos Islands, colonization, species formation, and threats to biodiversity. Discusses finches, tortoises, and sea cucumbers and provides instructions for student discussions. (YDS)

  16. Galapagos Islands

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This true-color image of the Galapagos Islands was acquired on March 12, 2002, by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra satellite. The Galapagos Islands, which are part of Ecuador, sit in the Pacific Ocean about 1000 km (620 miles) west of South America. As the three craters on the largest island (Isabela Island) suggest, the archipelago was created by volcanic eruptions, which took place millions of years ago. Unlike most remote islands in the Pacific, the Galapagos have gone relatively untouched by humans over the past few millennia. As a result, many unique species have continued to thrive on the islands. Over 95 percent of the islands' reptile species and nearly three quarters of its land bird species cannot be found anywhere else in the world. Two of the more well known are the Galapagos giant tortoise and marine iguanas. The unhindered evolutionary development of the islands' species inspired Charles Darwin to begin The Origin of Species eight years after his visit there. To preserve the unique wildlife on the islands, the Ecuadorian government made the entire archipelago a national park in 1959. Each year roughly 60,000 tourists visit these islands to experience what Darwin did over a century and a half ago. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  17. Diablotin Pterodroma hasitata: a biography of the endangered Black-capped Petrel

    USGS Publications Warehouse

    Simons, Theodore R.; Lee, David S.; Haney, J. Chris

    2013-01-01

    Our findings are in accord with the recent decision by the US Fish and Wildlife Service (USFWS) to evaluate the need for additional protection of the species and the primary foraging habitat off the southeastern United States under the Endangered Species Act (USFWS 2012). Additional conservation measures and research strategies that warrant further consideration include (1) protection, monitoring, and management of known breeding populations and nesting habitat in the Dominican Republic and Haiti through controlling predators, installing artificial nest burrows in appropriate sites and hiring local wardens at breeding sites during the nesting season; (2) local and regional training, education and public awareness (e.g. Blanchard & Nettleship 1992); (3) restoration of the original common name Diablotin to common usage to promote the historical and cultural importance of this species; (4) studies to determine the distribution and genetic variability in the remaining populations; and (5) studies of satellite-tagged birds to assess their seasonal and geographic use of pelagic habitats.

  18. The evolution of north-east Atlantic gadfly petrels using statistical phylogeography.

    PubMed

    Gangloff, B; Zino, F; Shirihai, H; González-Solís, J; Couloux, A; Pasquet, E; Bretagnolle, V

    2013-01-01

    Macaronesia (north-east Atlantic archipelagos) has been host to complex patterns of colonization and differentiation in many groups of organisms including seabirds such as gadfly petrels (genus Pterodroma). Considering the subspecies of widely distributed soft-plumaged petrel for many years, the taxonomic status of the three gadfly petrel taxa breeding in Macaronesia is not yet settled, some authors advocating the presence of three, two or one species. These birds have already been the subject of genetic studies with only one mtDNA gene and relatively modest sample sizes. In this study, using a total of five genes (two mitochondrial genes and three nuclear introns), we investigated the population and phylogeographical histories of petrel populations breeding on Madeira and Cape Verde archipelagos. Despite confirming complete lineage sorting with mtDNA, analyses with nucDNA failed to reveal any population structuring and Isolation with Migration analysis revealed the absence of gene flow during the differentiation process of these populations. It appears that the three populations diverged in the late Pleistocene in the last 150 000 years, that is 10 times more recently than previous estimates based solely on one mtDNA gene. Finally, our results suggest that the Madeira petrel population is ancestral rather than that from Cape Verde. This study strongly advocates the use of nuclear loci in addition to mtDNA in demographical and phylogeographical history studies. PMID:23171163

  19. First satellite tracks of the Endangered black-capped petrel

    USGS Publications Warehouse

    Jodice, Patrick G.; Ronconi, Robert A.; Rupp, Ernst; Wallace, George E.; Satgé, Yvan

    2015-01-01

    The black-capped petrel Pterodroma hasitata is an endangered seabird with fewer than 2000 breeding pairs restricted to a few breeding sites in Haiti and the Dominican Republic. To date, use areas at sea have been determined entirely from vessel-based surveys and opportunistic sightings and, as such, spatial and temporal gaps in our understanding of the species’ marine range are likely. To enhance our understanding of marine use areas, we deployed satellite tags on 3 black-capped petrels breeding on Hispaniola, representing the first tracking study for this species and one of the first published tracking studies for any breeding seabird in the Caribbean. During chick rearing, petrels primarily used marine habitats in the southern Caribbean Sea (ca. 18.0° to 11.5°N, 70.0° to 75.5°W) between the breeding site and the coasts of Venezuela and Colombia. Maximum distance from the breeding sites ranged from ca. 500 to 1500 km during the chick-rearing period. During the post-breeding period, each bird dispersed north and used waters west of the Gulf Stream offshore of the mid- and southern Atlantic coasts of the USA as well as Gulf Stream waters and deeper pelagic waters east of the Gulf Stream. Maximum distance from the breeding sites ranged from ca. 2000 to 2200 km among birds during the nonbreeding period. Petrels used waters located within 14 different exclusive economic zones, suggesting that international collaboration will benefit the development of management strategies for this species.

  20. Thermoregulation in Antarctic fulmarine petrels.

    PubMed

    Weathers, W W; Gerhart, K L; Hodum, P J

    2000-12-01

    We measured resting metabolic rates at air temperatures between ca. -5 and 30 degrees C in snow petrels (Pagodroma nivea), cape petrels (Daption capense), Antarctic petrels (Thalassoica antarctica), and Antarctic fulmars (Fulmarus glacialoides). We measured seven age classes for each species: adults, and nestlings that were 3, 8, 15, 28, 35, and 42 days old. Basal metabolic rate (BMR) and thermal conductance (C) of adults averaged, respectively, 140% and 100% of values predicted allometrically for nonpasserine birds. Minimum metabolic rates of unfasted nestlings aged 15-42 days averaged, respectively, 97% and 98% of predicted adult BMR in Antarctic petrels and snow petrels, versus 119% and 126% of predicted in Antarctic fulmars and cape petrels. Nestlings of the southerly breeding snow petrel and Antarctic petrel were relatively well insulated compared with nestlings of other high-latitude seabirds. Adult lower critical temperature (T1c) was inversely related to body mass and averaged 9 degrees C lower than predicted allometrically. As nestlings grew, their T1c decreased with increasing body mass from ca. 14 to 22 degrees C (depending upon species) at 3 days of age, to -4 to 8 degrees C when nestlings attained peak mass. Nestling T1c subsequently increased as body mass decreased during pre-fledging weight recession. Nestling T1c was close to mean air temperature from the end of brooding until fledging in the three surface nesting species. PMID:11192262

  1. The Galapagos Jason Curriculum.

    ERIC Educational Resources Information Center

    National Science Teachers Association, Arlington, VA.

    The JASON Curriculum Project materials are designed to prepare teachers and students for an exploration around the Galapagos Islands via satellite transmission of live images and sound. This curriculum package contains five units, 25 lesson plans, and over 50 activities, along with teacher background material, student worksheets and readings, a…

  2. Stable Isotopic Insights into the Foraging Ecology of an Endangered Marine Predator, the Hawaiian Petrel

    NASA Astrophysics Data System (ADS)

    Wiley, A. E.; Ostrom, P. H.; James, H. F.

    2010-12-01

    Seabirds play vital roles in their ecosystems, both as predators in their oceanic foraging grounds and conduits of marine nutrients to island nesting sites. Despite growing evidence that food availability limits seabird populations, characterization of the diet and even foraging locations of some seabird species remains elusive. Here, we use stable carbon (δ13C) and nitrogen (δ15N) isotopes to study the foraging ecology of an endangered and poorly known seabird, the Hawaiian petrel (Pterodroma sandwichensis). This species nests solely on the main Hawaiian Islands but forages widely across the NE Pacific, sometimes traveling over 10,000km on single foraging trips. δ13C and δ15N values vary with trophic level and at the base of food webs throughout the marine range of the Hawaiian petrel. Thus, we are able to use isotope signatures in modern and ancient petrel tissues to track spatial and temporal variation in foraging location and diet. We find strong evidence of foraging segregation between populations, with hatch-year birds from the island of Hawaii exhibiting feather δ15N and δ13C values over 3‰ and 1 ‰ higher, respectively, than those found in Maui and Kauai hatch-year birds. There is also significant variation in δ15N values between feathers from Kauai, Hawaii, and Maui adults, indicating additional foraging segregation during the winter molt. To distinguish between the effects of trophic level and foraging location, we relate our data to those from seabirds with known diet and foraging location, as well as to previous characterizations of isoscapes in the NE Pacific and at-sea observations of our study species. Finally, we track Hawaiian petrel foraging ecology back in time through examination of stable isotope values in historical feathers and ancient bone collagen. We find that, despite a species-wide decline in δ15N values (consistent with trophic level decline), populations have maintained divergent isotopic niches through at least the past 1

  3. Speciation and phylogeography of giant petrels Macronectes.

    PubMed

    Techow, N M S M; O'Ryan, C; Phillips, R A; Gales, R; Marin, M; Patterson-Fraser, D; Quintana, F; Ritz, M S; Thompson, D R; Wanless, R M; Weimerskirch, H; Ryan, P G

    2010-02-01

    We examine global phylogeography of the two forms of giant petrel Macronectes spp. Although previously considered to be a single taxon, and despite debate over the status of some populations and the existence of minimal genetic data (one mitochondrial cytochrome b sequence per form), the current consensus based on morphology is that there are two species, Northern Giant Petrel M. halli and Southern Giant Petrel M. giganteus. This study examined genetic variation at cytochrome b as well as six microsatellite loci in giant petrels from 22 islands, representing most island groups at which the two species breed. Both markers support separate species status, although sequence divergence in cytochrome b was only 0.42% (corrected). Divergence was estimated to have occurred approximately 0.2mya, but with some colonies apparently separated for longer (up to 0.5 my). Three clades were found within giant petrels, which separated approximately 0.7mya, with the Southern Giant Petrel paraphyletic to a monophyletic Northern Giant Petrel. There was evidence of past fragmentation during the Pleistocene, with subsequent secondary contact within Southern Giant Petrels. The analysis also suggested a period of past population expansion that corresponded roughly to the timing of speciation and the separation of an ancestral giant petrel population from the fulmar Fulmarus clade. PMID:19755164

  4. Global phylogeography of the band-rumped storm-petrel (Oceanodroma castro; Procellariiformes: Hydrobatidae).

    PubMed

    Smith, Andrea L; Monteiro, Luis; Hasegawa, Osamu; Friesen, Vicki L

    2007-06-01

    Factors shaping population differentiation in low latitude seabirds are not well-understood. In this study, we examined global patterns of DNA sequence variation in the mitochondrial control region of the band-rumped storm-petrel (Oceanodroma castro), a highly pelagic seabird distributed across the sub-tropical and tropical Atlantic and Pacific Oceans. Despite previous classification as a single, monotypic species, fixed haplotype differences occurred between Atlantic and Pacific populations, and among all Pacific populations. In addition, Cape Verde and Galapagos birds formed distinct clades, estimated to have diverged from all other populations at least 150,000years ago. Azores hot season populations were also genetically distinct, lending support to previous phenotypic evidence that they be recognized as a separate species. Seasonal populations in Madeira probably represent separate genetic management units. The phylogeography of the band-rumped storm-petrel appears to have been shaped by both nonphysical barriers to gene flow and Pleistocene oceanographic conditions. Ancestral populations likely expanded through contiguous range expansion and infrequent long-distance colonization into their current breeding range. These findings suggest several possible revisions to the taxonomy of the band-rumped storm-petrel. PMID:17408975

  5. The Galapagos Microplate Revealed

    NASA Astrophysics Data System (ADS)

    Smith, D. K.; Schouten, H.; Cann, J. R.; Zhu, W.; Montesi, L. G.; Mitchell, G. A.

    2009-12-01

    We report a new bathymetry survey of the Galapagos microplate (GMP), which separates the Pacific, Nazca, and Cocos plates at the Galapagos Triple Junction. Prior to the formation of the microplate, 1.5-1.0 Ma, there was a succession of transient minor rifts forming triple junctions north and south of the propagating Cocos-Nazca rift (see Schouten et al. abstract). As proposed by Lonsdale (1988) the formation of a large near-axis seamount coincided with the initiation of the GMP and stabilized rifting on its southern boundary, now called Dietz Deep Rift. Lonsdale also proposed that the GMP was rotating clockwise at 6 degrees/my. Schouten et al. (1993) and Klein et al. (2005) applied an edge-driven microplate model to the GMP to understand its kinematics and predicted rotation rates of 30-40 degrees/my and 22 degrees/my, respectively. These interpretations and predictions were based on sparse bathymetry data. In early 2009 (AT 15-41), we mapped the Galapagos microplate in its entirety to understand more fully the conditions that led to the stabilization of the southern triple junction at Dietz Deep Rift and to constrain the rotation rate of the microplate. Our new data show the two highly contrasted sections of Dietz Deep Rift. The northeastern section contains Dietz Deep, a 2 km deep basin, within a fault-dominated rift valley about 20 km wide; subsidiary rifts occur to the south. Sidescan data indicate that extension in this broadly rifted area has been largely amagmatic. The southwestern section of Dietz Deep Rift is dominated by a variety of volcanic constructions in which faulting plays a minor part. The volcanism has resulted in two large seamounts and a number of volcanic ridges running parallel to the fault dominated rift valley. The largest volcanic ridge is steep-sided and straight, and extends to intersect the East Pacific Rise (EPR) at 1 10’N to form the triple junction. Other minor volcanic ridges occur in the SW section of the microplate fanning

  6. Genetic divergence among extant and extirpated colonies of an endangered pelagic seabird, the Hawaiian petrel

    NASA Astrophysics Data System (ADS)

    Welch, A. J.; Fleischer, R. C.; James, H. F.

    2010-12-01

    It is important to consider both the temporal and spatial dimensions of variability in ecology and evolution. Given the potentially great dispersal capabilities and long generation times of pelagic seabirds, genetic diversity in these species seems likely to be homogeneously distributed and relatively static over time. Investigating temporal and spatial processes involved in the ecology and evolution of seabird populations is important to island ecosystem sustainability, as they play a significant role in transferring marine derived nutrients to terrestrial oceanic ecosystems. Additionally, many seabird species are threatened by extinction due to increasing mortality both at land and at sea. Here we investigate population divergence of the endemic and endangered Hawaiian petrel (Pterodroma sandwichensis). We examined four extant colonies on the islands of Hawaii, Maui, Lanai and Kauai, and employed ancient DNA techniques to study a prehistorically extirpated colony on Oahu, and a historically large, but likely extirpated, colony on the island of Molokai. Analyses of sequences of the mitochondrial cytochrome b gene as well as nuclear microsatellite markers indicate substantial differentiation (global Φst of 0.38, p < 0.0001). Significant divergence was found among each pair of the six islands except between Oahu and Molokai (Φst = 0.10, p = 0.07). However, this could result from low power due to the limited availability of amplifiable samples, especially for the hot, low elevation colony formerly present on Oahu. The largest differentiation occurred between the islands of Lanai and Kauai (Φst = 0.58, p < 0.0001). These results suggest that despite their great dispersal capabilities, spatially proximate colonies of the Hawaiian petrel are not genetically homogenous. Additionally, the extirpation of large colonies, such as those on Oahu and Molokai, could result in loss of a substantial amount of genetic diversity. Future work should further investigate temporal

  7. Ancient DNA reveals genetic stability despite demographic decline: 3,000 years of population history in the endemic Hawaiian petrel.

    PubMed

    Welch, Andreanna J; Wiley, Anne E; James, Helen F; Ostrom, Peggy H; Stafford, Thomas W; Fleischer, Robert C

    2012-12-01

    In the Hawaiian Islands, human colonization, which began approximately 1,200 to 800 years ago, marks the beginning of a period in which nearly 75% of the endemic avifauna became extinct and the population size and range of many additional species declined. It remains unclear why some species persisted whereas others did not. The endemic Hawaiian petrel (Pterodroma sandwichensis) has escaped extinction, but colonies on two islands have been extirpated and populations on remaining islands have contracted. We obtained mitochondrial DNA sequences from 100 subfossil bones, 28 museum specimens, and 289 modern samples to investigate patterns of gene flow and temporal changes in the genetic diversity of this endangered species over the last 3,000 years, as Polynesians and then Europeans colonized the Hawaiian Islands. Genetic differentiation was found to be high between both modern and ancient petrel populations. However, gene flow was substantial between the extirpated colonies on Oahu and Molokai and modern birds from the island of Lanai. No significant reductions in genetic diversity occurred over this period, despite fears in the mid-1900s that this species may have been extinct. Simulations show that even a decline to a stable effective population size of 100 individuals would result in the loss of only 5% of the expected heterozygosity. Simulations also show that high levels of genetic diversity may be retained due to the long generation time of this species. Such decoupling between population size and genetic diversity in long-lived species can have important conservation implications. It appears that a pattern of dispersal from declining colonies, in addition to long generation time, may have allowed the Hawaiian petrel to escape a severe genetic bottleneck, and the associated extinction vortex, and persist despite a large population decline after human colonization. PMID:22844071

  8. Ancient DNA reveals genetic stability despite demographic decline: 3,000 years of population history in the endemic Hawaiian petrel.

    PubMed

    Welch, Andreanna J; Wiley, Anne E; James, Helen F; Ostrom, Peggy H; Stafford, Thomas W; Fleischer, Robert C

    2012-12-01

    In the Hawaiian Islands, human colonization, which began approximately 1,200 to 800 years ago, marks the beginning of a period in which nearly 75% of the endemic avifauna became extinct and the population size and range of many additional species declined. It remains unclear why some species persisted whereas others did not. The endemic Hawaiian petrel (Pterodroma sandwichensis) has escaped extinction, but colonies on two islands have been extirpated and populations on remaining islands have contracted. We obtained mitochondrial DNA sequences from 100 subfossil bones, 28 museum specimens, and 289 modern samples to investigate patterns of gene flow and temporal changes in the genetic diversity of this endangered species over the last 3,000 years, as Polynesians and then Europeans colonized the Hawaiian Islands. Genetic differentiation was found to be high between both modern and ancient petrel populations. However, gene flow was substantial between the extirpated colonies on Oahu and Molokai and modern birds from the island of Lanai. No significant reductions in genetic diversity occurred over this period, despite fears in the mid-1900s that this species may have been extinct. Simulations show that even a decline to a stable effective population size of 100 individuals would result in the loss of only 5% of the expected heterozygosity. Simulations also show that high levels of genetic diversity may be retained due to the long generation time of this species. Such decoupling between population size and genetic diversity in long-lived species can have important conservation implications. It appears that a pattern of dispersal from declining colonies, in addition to long generation time, may have allowed the Hawaiian petrel to escape a severe genetic bottleneck, and the associated extinction vortex, and persist despite a large population decline after human colonization.

  9. Galapagos Tectonics and Evolution (Invited)

    NASA Astrophysics Data System (ADS)

    Hey, R. N.

    2010-12-01

    Galapagos is now considered one of the type-examples of hotspot-ridge interaction, although in the early years of plate tectonics it was generally thought that this interpretation was demonstrably wrong, with two influential groups insisting that non-hotspot models were required for this area. The key to understanding Galapagos tectonic evolution was the recognition that small ridge axis jumps toward the hotspot had occurred, producing complicated magnetic anomalies and asymmetric lithospheric accretion. My dissertation work, guided by Jason Morgan, showed that this simple modification to plate tectonic theory could resolve the seemingly compelling geometric arguments against the Cocos and Carnegie aseismic ridges being Galapagos hotspot tracks, and further that if Galapagos were a hotspot near Fernandina, fixed with respect to the Hawaii hotspot, there should be aseismic ridges on the Cocos and Nazca plates with the observed Cocos and Carnegie ridge geometry, both aseismic ridges forming when the hotspot was ridge-centered, but only the Carnegie ridge since the plate boundary migrated north of the hotspot. A great deal of subsequent research has shown that some areas are considerably more complicated than originally thought, but the following basic model still appears to hold. The Farallon plate split apart along the Grijalva scarp, possibly a preexisting Pacific-Farallon FZ that intersected the hotspot at this time (although alternative interpretations exist), probably in response to tensional stress caused by slab pull in different directions at the Mid-America and Peru-Chile trenches. This break-up allowed more orthogonal subduction of independent Cocos and Nazca plates beginning shortly after 25 Ma. The original Cocos-Nazca ridge trended E-NE, but soon reorganized into N-S spreading segments. The subsequent evolution involved substantial northward ridge migration and ridge jumps, mostly toward the Galapagos hotspot. Recent ridge jumps have occurred in

  10. Mechanisms of global diversification in the marine species Madeiran Storm-petrel Oceanodroma castro and Monteiro's Storm-petrel O. monteiroi: Insights from a multi-locus approach.

    PubMed

    Silva, Mauro F; Smith, Andrea L; Friesen, Vicki L; Bried, Joël; Hasegawa, Osamu; Coelho, M Manuela; Silva, Mónica C

    2016-05-01

    The evolutionary mechanisms underlying the geographic distribution of gene lineages in the marine environment are not as well understood as those affecting terrestrial groups. The continuous nature of the pelagic marine environment may limit opportunities for divergence to occur and lineages to spatially segregate, particularly in highly mobile species. Here, we studied the phylogeography and historical demography of two tropically distributed, pelagic seabirds, the Madeiran Storm-petrel Oceanodroma castro, sampled in the Azores, Madeira, Galapagos and Japan, and its sister species Monteiro's Storm-petrel O. monteiroi (endemic to the Azores), using a multi-locus dataset consisting of 12 anonymous nuclear loci and the mitochondrial locus control region. Both marker types support the existence of four significantly differentiated genetic clusters, including the sampled O. monteiroi population and three populations within O. castro, although only the mitochondrial locus suggests complete lineage sorting. Multi-locus coalescent analyses suggest that most divergence events occurred within the last 200,000years. The proximity in divergence times precluded robust inferences of the species tree, in particular of the evolutionary relationships of the Pacific populations. Despite the great potential for dispersal, divergence among populations apparently proceeded in the absence of gene flow, emphasizing the effect of non-physical barriers, such as those driven by the paleo-oceanographical environments, philopatry and local adaptation, as important mechanisms of population divergence and speciation in highly mobile marine species. In view of the predicted climate change impacts, future changes in the demography and evolutionary dynamics of marine populations might be expected. PMID:26921843

  11. Mechanisms of global diversification in the marine species Madeiran Storm-petrel Oceanodroma castro and Monteiro's Storm-petrel O. monteiroi: Insights from a multi-locus approach.

    PubMed

    Silva, Mauro F; Smith, Andrea L; Friesen, Vicki L; Bried, Joël; Hasegawa, Osamu; Coelho, M Manuela; Silva, Mónica C

    2016-05-01

    The evolutionary mechanisms underlying the geographic distribution of gene lineages in the marine environment are not as well understood as those affecting terrestrial groups. The continuous nature of the pelagic marine environment may limit opportunities for divergence to occur and lineages to spatially segregate, particularly in highly mobile species. Here, we studied the phylogeography and historical demography of two tropically distributed, pelagic seabirds, the Madeiran Storm-petrel Oceanodroma castro, sampled in the Azores, Madeira, Galapagos and Japan, and its sister species Monteiro's Storm-petrel O. monteiroi (endemic to the Azores), using a multi-locus dataset consisting of 12 anonymous nuclear loci and the mitochondrial locus control region. Both marker types support the existence of four significantly differentiated genetic clusters, including the sampled O. monteiroi population and three populations within O. castro, although only the mitochondrial locus suggests complete lineage sorting. Multi-locus coalescent analyses suggest that most divergence events occurred within the last 200,000years. The proximity in divergence times precluded robust inferences of the species tree, in particular of the evolutionary relationships of the Pacific populations. Despite the great potential for dispersal, divergence among populations apparently proceeded in the absence of gene flow, emphasizing the effect of non-physical barriers, such as those driven by the paleo-oceanographical environments, philopatry and local adaptation, as important mechanisms of population divergence and speciation in highly mobile marine species. In view of the predicted climate change impacts, future changes in the demography and evolutionary dynamics of marine populations might be expected.

  12. Health evaluation of Galapagos Hawks (Buteo galapagoensis) on Santiago Island, Galapagos.

    PubMed

    Deem, Sharon L; Rivera-Parra, Jose Luis; Parker, Patricia G

    2012-01-01

    Galapagos Hawks (Buteo galapagoensis), the only endemic, diurnal raptor species in Galapagos, are currently distributed on eight Galapagos Islands having been extirpated from three of the human-inhabited islands. In January 2009, we performed health assessments of 89 Galapagos Hawks on Santiago Island, Galapagos. Four of the 89 Galapagos Hawks (4%) evaluated had physical abnormalities. Blood parameters did not differ between males and females, except for aspartate transaminase values, which were significantly higher in females than males. No Galapagos Hawks tested positive for antibodies to avian encephalitis virus, Marek virus, and paramyxovirus-1 or to haemosporidian antigen. Chlamydophila psittaci antigen was detected in 2 of 86 Galapagos Hawks (2%), with 24 of 43 Galapagos Hawks (56%) antibody-positive for avian adenovirus-1 and 1 of 48 Galapagos Hawks (2%) antibody positive for Toxoplasma gondii. There were no significant differences in infectious disease results based on sex. This study contributes to the understanding of the health status of the Galapagos Hawk and to the establishment of baseline information for the species.

  13. Phylogeography and taxonomy of White-chinned and Spectacled Petrels.

    PubMed

    Mareile Techow, N M S; Ryan, Peter G; O'Ryan, Colleen

    2009-07-01

    The genus Procellaria traditionally consists of four species, two restricted to New Zealand and two widespread in the Southern Ocean. All four are threatened because of incidental mortality on longlines and other fishing gear. The White-chinned Petrel P. aequinoctialis is the seabird killed in largest numbers by fisheries in the Southern Ocean. A spectacled form recently has been elevated to species status, Spectacled Petrel P. conspicillata, based on differences in morphometrics, vocalisations and breeding phenology. Cytochrome b sequences support species status for the Spectacled Petrel and show that the White-chinned Petrel has two regional populations, one around New Zealand and one throughout the South Atlantic and Indian Oceans. White-chinned and Spectacled Petrels segregated approximately 0.90 million years ago by allopatric fragmentation, and the two populations within White-chinned Petrels diverged approximately 0.35 million years ago. Climate changes and corresponding changes in ocean currents are most likely responsible for these patterns. PMID:19364537

  14. Interaction between the Hawaiian dark-rumped petrel and the Argentine ant in Haleakala National Park, Maui, Hawaii

    USGS Publications Warehouse

    Krushelnycky, Paul D.; Hodges, Cathleen S.N.; Medeiros, Arthur C.; Loope, Lloyd L.

    2001-01-01

    The endemic biota of the Hawaiian islands is believed to have evolved in the absence of ant predation. However, it was suspected that this endemic biota is highly vulnerable to the effect of immigrant ants especially with regard to an aggressive predator known as the Argentine ant (Linepithema humile). First recorded in the Haleakala National Park on the island of Maui in 1967, this ant was believed to have reduced populations of native arthropods in high-elevation subalpine shrublands. In addition, concerns were raised that this immigrant ant may have also reduced the breeding success of the endangered Hawaiian Dark-rumped Petrel (Pterodroma phaeopygia sandwichensis), a native seabird. If so, then it was believe that this ant could become another major threat to the survival of this endangered seabird in addition to the threat that was caused by the introduction of introduced mammals, the advent of hunting by the Polynesians, and a loss of breeding habitat. As a result, the purpose of this study was to determine if the Argentine ant affects the nesting success of this native Hawaiian seabird.

  15. Radar Image of Galapagos Island

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is an image showing part of Isla Isabella in the western Galapagos Islands. It was taken by the L-band radar in HH polarization from the Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar on the 40th orbit of the space shuttle Endeavour. The image is centered at about 0.5 degree south latitude and 91 degrees west longitude and covers an area of 75 by 60 kilometers (47 by 37 miles). The radar incidence angle at the center of the image is about 20 degrees.

    The western Galapagos Islands, which lie about 1,200 kilometers (750 miles) west of Ecuador in the eastern Pacific, have six active volcanoes similar to the volcanoes found in Hawaii. Since the time of Charles Darwin's visit to the area in 1835, there have been over 60 recorded eruptions of these volcanoes. This SIR-C/X-SAR image of Alcedo and Sierra Negra volcanoes shows the rougher lava flows as bright features, while ash deposits and smooth pahoehoe lava flows appear dark. A small portion of Isla Fernandina is visible in the extreme upper left corner of the image.

    The Galapagos Islands are one of the SIR-C/X-SAR supersites and data of this area will be taken several times during the flight to allow scientists to conduct topographic change studies and to search for different lava flow types, ash deposits and fault lines.

    Spaceborne Imaging Radar-C and X-Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes

  16. Galapagos: Darwin, evolution, and ENT.

    PubMed

    Bluestone, Charles D

    2009-10-01

    This year is especially important in the history of the theory of evolution; 2009 is the bicentennial anniversary of the birth of Charles Darwin and the sesquicentennial anniversary of his publication, The Origin of Species. Darwin visited the Galapagos Islands as a young man, which greatly influenced his thinking. My son Jim and I had the good fortune to visit these islands in January 2009 and see firsthand what led Darwin to arrive at his monumental insights into the origins of life on this planet. I have described my observations and related some of this experience to the ear, nose, and throat, albeit with whimsy in several instances. Nonetheless, some of the adaptations in the animals on these unique islands may have bearing on my hypotheses related to the incidence and pathogenesis of otitis media in humans. It is hoped the reader will share my enthusiasm for the experience we had on these fantastic islands and tour them in the future. PMID:19658158

  17. Galapagos: Darwin, evolution, and ENT.

    PubMed

    Bluestone, Charles D

    2009-10-01

    This year is especially important in the history of the theory of evolution; 2009 is the bicentennial anniversary of the birth of Charles Darwin and the sesquicentennial anniversary of his publication, The Origin of Species. Darwin visited the Galapagos Islands as a young man, which greatly influenced his thinking. My son Jim and I had the good fortune to visit these islands in January 2009 and see firsthand what led Darwin to arrive at his monumental insights into the origins of life on this planet. I have described my observations and related some of this experience to the ear, nose, and throat, albeit with whimsy in several instances. Nonetheless, some of the adaptations in the animals on these unique islands may have bearing on my hypotheses related to the incidence and pathogenesis of otitis media in humans. It is hoped the reader will share my enthusiasm for the experience we had on these fantastic islands and tour them in the future.

  18. Galapagos

    Atmospheric Science Data Center

    2013-04-19

    ... human settlements on this island. Several plant species are endangered due to decimation by goats and competition with ... are contributing to the endangered status of native plant species such as the endemic daisy tree and the Floreana flax. El ...

  19. The origin and diversification of Galapagos mockingbirds.

    PubMed

    Arbogast, Brian S; Drovetski, Sergei V; Curry, Robert L; Boag, Peter T; Seutin, Gilles; Grant, Peter R; Grant, B Rosemary; Anderson, David J

    2006-02-01

    Evolutionary radiations of colonists on archipelagos provide valuable insight into mechanisms and modes of speciation. The apparent diversification of Galapagos mockingbirds (Nesomimus) provoked Darwin's initial conception of adaptive radiation, but the monophyly of this historically important exemplar has not been evaluated with molecular data. Additionally, as with most Galapagos organisms, we have a poor understanding of the temporal pattern of diversification of the mockingbirds following colonization(s) from source populations. Here we present a molecular phylogeny of Galapagos and other mockingbird populations based on mitochondrial sequence data. Monophyly of Galapagos mockingbirds was supported, suggesting a single colonization of the archipelago followed by diversification. Our analyses also indicate that Nesomimus is nested within the traditional genus Mimus, making the latter paraphyletic, and that the closest living relatives of Galapagos mockingbirds appear to be those currently found in North America, northern South America, and the Caribbean, rather than the geographically nearest species in continental Ecuador. Thus, propensity for over-water dispersal may have played a more important role than geographic proximity in the colonization of Galapagos by mockingbirds. Within Galapagos, four distinct mitochondrial DNA clades were identified. These four clades differ from current taxonomy in several important respects. In particular, mockingbirds in the eastern islands of the archipelago (Española, San Cristóbal, and Genovesa) have very similar mitochondrial DNA sequences, despite belonging to three different nominal species, and mockingbirds from Isabela, in the west of the archipelago, are more phylogenetically divergent than previously recognized. Consistent with current taxonomy is the phylogenetic distinctiveness of the Floreana mockingbird (N. trifasciatus) and close relationships among most mockingbirds from the central and northern region of the

  20. Hydrogeology of the Galapagos Islands

    NASA Astrophysics Data System (ADS)

    D'Ozouville, N.; Pryet, A.; Violette, S.; de Marsily, G.; Deffontaines, B.; Auken, E.

    2010-12-01

    Due to the heterogeneity of geological formations, volcanic islands present complex and contrasting hydrogeological settings. A young discipline in the Galapagos, hydrogeology requires an understanding of geology, geomorphology, climate and hydrology. Throughout history, navigators, scientists and inhabitants noted the lack of surface freshwater; and water availability limited settlement of the islands. Today, this limitation is overcome through groundwater exploitation and expensive desalination, fed by economic growth. This shift has freed the field of hydrogeology from the existing premise of water being the principal drive for human development. Within this context, our approach is to lead a pluri-disciplinary research to characterize Galapagos hydrogeology. It involves a long-term commitment with international, national and local partners. Field investigations conducted on the inhabited islands of Santa Cruz, San Cristobal, Isabela and Floreana reveal three types of aquifers. A low-lying basal aquifer outcrops on Santa Cruz and Isabela. Due to the high permeability of fractured shield series forming coastal aprons, intruding sea water mixes with discharging freshwater, and confers a high salt content to groundwater. In order to characterize the hydraulic properties of this aquifer, the propagation of the tidal signal into the basal aquifer has been investigated through piezometric monitoring in three open coastal fractures and the deep well on Santa Cruz. Springs are scarce in the Archipelago, but have been identified historically on Santa Cruz and Floreana, located on the flanks of volcanic cones, and fed by small perched aquifers. On San Cristobal, high-level aquifers feed springs on the southern mountainside that contribute to a network of permanent rivers that reach the sea, a unique feature in the whole archipelago. They are independent from El Junco, a unique summital freshwater, and semi-endoreic lake. Internal resistivity structure of Santa Cruz and

  1. Rotavirus infections in Galapagos sea lions.

    PubMed

    Coria-Galindo, Elsa; Rangel-Huerta, Emma; Verdugo-Rodríguez, Antonio; Brousset, Dulce; Salazar, Sandie; Padilla-Noriega, Luis

    2009-07-01

    Group A rotaviruses infect and cause diarrhea in the young of a broad range of terrestrial mammals, but it is unknown, to our knowledge, whether they infect marine mammals. During February and March of 2002 and 2003, we collected 125 serum samples and 18 rectal swab samples from Galapagos sea lion pups (GSL, Zalophus wollebaeki), and 22 serum samples from Galapagos fur seal pups (GFS, Arctocephalus galapagoensis) from nine islands of the Galapagos archipelago, Ecuador. Sera were tested for antibodies (immunoglobulin G [IgG]) to rotavirus by an enzyme immunoassay using rhesus rotavirus as the capture antigen. In addition, rectal swabs were analyzed for the presence of rotavirus genomic double-stranded RNA by silver-stained polyacrylamide gel electrophoresis. Antibodies to rotavirus were detected in 27 GSL pups (22%) and five GFS pups (23%), and rotavirus RNA was detected in the fecal sample from one GSL pup (6%). These results provide the first evidence that rotavirus infections are prevalent at an early age in Galapagos sea lions and Galapagos fur seals.

  2. Olfaction in petrels: from homing to self-odor avoidance.

    PubMed

    Bonadonna, Francesco

    2009-07-01

    In the 1960s, Betsy Bang unraveled the complexity of the olfactory apparatus of procellariiform seabirds (petrels and albatrosses), suggesting an important role for olfaction in their ecology. Shortly thereafter, Prof. B. Wenzel continued the investigations on petrels' well-developed olfactory neuroanatomy as well as their sensitivity to food-related scents. Later studies demonstrated further that the sense of smell is also critical to these birds when homing to their burrow. Building on these findings, we have demonstrated in several petrel species the importance of the burrow olfactory signature in homing. The nature of this olfactory signature relies predominantly on their mate's odor. Indeed, in our Y-maze experiments, Antarctic prions (Pachyptila desolata) and blue petrels (Halobaena caerulea) could discriminate between their own and their mates' odors. However, although they are attracted by their mate odor, they prefer the odor of a conspecific bird to their own. These results have drawn attention to the possible use of chemical signals in birds' social behaviors, such as individual recognition and/or mate choice. Indeed, petrel life history traits suggest that olfactory-mediated mate choice may have evolved in this group to ensure genetic compatibility between mates. We have recently shown that a bird's semiochemical profile is more similar to itself, year after year, than to that of a conspecific. As a result, a novel function of olfaction emerges in petrels: the perception of a chemical signal that may broadcast individuals' identity and quality, thereby contributing to an optimal mate choice. PMID:19686171

  3. The Incredible Shrinking Iguana: Impact of Galapagos

    NASA Astrophysics Data System (ADS)

    Murtugudde, R.; Karnauskas, K.

    2007-05-01

    Galapagos Islands are well known for Darwin's epiphany about evolution after his 'discovery' of the islands. The incredible transformation that the key species on this island undergo on ENSO time-scales is recorded extensively. The impact of Galapagos on SSTs and ocean primary production has been conjectured but some recent work demonstrates that their influence extdends thousands of kilometers via stronger TIWs and modulations of the termination of EUC and related air-sea interactions. Tropical Pacific is not only the theater of action for ENSO dynamics but the ecosystem is the most studied iron limited region due to its HNLC characteristics. This study addresses the physical and biogeochemical impacts of the Galapagos islands with a OGCM-biogeochemical model coupled to a simple wind-anomaliy model. The impact of Galapagos is to warm the cold-tongue by upto 1C with a major impact on the termination of the EUC that results in large-scale circulation changes that extend to the South American coast as far south as 20S. If the islands are not included, then the equatorial Kelvin waves extend their impact on thermocline variability all the way to the eastern boundary and lead to a quasi-biennial ENSO whereas the impact of Galapagos islands shifts the frequency to a quasi- quadrennial time-scale. The impacts on the ecosystem are commensurate with the seasonal and interannual variability changes with the addition of dissolved iron supply related to EUC changes. Bio-physical feedbacks in the deep tropical Pacific also tend to warm SSTs and the impact of Galapagos is thus to flatten the east-west SST gradient resulting in less-frequent and weaker ENSO events. The relevance of these results to longer time-scale variability and any potential analogs to global warming and sea level change are discussed in detail.

  4. Could osmotaxis explain the ability of blue petrels to return to their burrows at night?

    PubMed

    Bonadonna, F; Spaggiari, J; Weimerskirch, H

    2001-04-01

    Like many other species of petrel, blue petrel (Halobaena caerulea) are able to return to their nest burrows at night in complete darkness. Since petrels have a well-developed olfactory system, we carried out an experiment to test whether blue petrels use olfaction to localise their nest burrows. Incubating birds were injected intranasally with a zinc sulphate solution, which reversibly impairs the sensitivity of the olfactory mucosa; control birds were treated with physiological saline solution. None of the anosmic birds returned to their burrows, whereas all the birds treated with saline solution did. Our results suggest that olfactory cues are necessary for blue petrels to find their burrows. PMID:11273809

  5. DDT residues and declining reproduction in the Bermuda petrel.

    PubMed

    Wurster, C F; Wingate, D B

    1968-03-01

    Residues of DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] averaging 6.44 parts per million in eggs and chicks of the carnivorous Bermuda petrel indicate widespread contamination of an oceanic food chain that is remote from applications of DDT. Reproduction by the petrel has declined during the last 10 years at the annual rate of 3.25 percent; if the decline continues, reproduction will fail completely by 1978. Concentrations of residues are similar to those in certain terrestrial carnivorous birds whose productivity is also declining. Various considerations implicate contamination by insecticides as a probable major cause of the decline. PMID:5635996

  6. Avian cholera in Southern Great Petrel (Macronectes giganteus) from Antarctica

    USGS Publications Warehouse

    Leotta, G.A.; Rivas, M.; Chinen, I.; Vigo, G.B.; Moredo, F.A.; Coria, N.; Wolcott, M.J.

    2003-01-01

    A southern giant petrel (Macronectes giganteus) was found dead at Potter Peninsula, King George Island, South Shetland, Antarctica. The adult male was discovered approximately 48 hr after death. Macroscopic and microscopic lesions were compatible with avian cholera and the bacterium Pasteurella multocida subsp. gallicida, serotype A1 was isolated from lung, heart, liver, pericardial sac, and air sacs. In addition, Escherichia coli was isolated from pericardial sac and air sacs. This is the first known report of avian cholera in a southern giant petrel in Antarctica.

  7. Promise seen in Petrel sub-basin off northwestern Australia

    SciTech Connect

    Maung, T.U.; Passmore, V. )

    1995-01-30

    The Australian government during the past 11 years has been regularly releasing vacant areas on the Australian continental shelf for exploration. Although Australia's offshore basins cover an area of 12 million sq km, only about 1,100 exploration and development wells have been drilled, and most of the basins are underexplored by world standards. One of these areas is the Petrel sub-basin of the Bonaparte basin in water shallower than 100 m off Northwest Australia. The government recently released six areas in the southern offshore Petrel subbasin for petroleum exploration. The results of a study by the Petroleum Resources Branch of the bureau of Resource Sciences have been synthesized into a Petrel Sub-basin Bulletin, some selections of which are discussed in this article. Although there are over 44,000 km of seismic data recorded in the sub-basin, the quality of pre-1979 data is very poor to poor, and only 15,800 km of data recorded between 1980--94 (including 1,000 km of 3D seismic data over the Barnett structure) are of fair to good quality. The paper describes the regional geology, reservoir and seals, source rocks, and types of geologic traps. The study identified over 30 structures and leads in the offshore southern Petrel sub-basin. Significant opportunities exist for delineation and definition of drillable prospects in this promising Australian petroleum province.

  8. 75 FR 235 - Endangered and Threatened Wildlife and Plants; Final Rule To List the Galapagos Petrel and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-05

    ...-day finding on May 12, 1981 (46 FR 26464), for 58 foreign species and initiated a status review. On January 20, 1984 (49 FR 2485), we published a 12-month finding within an annual review on pending... listing actions. On May 10, 1985, we published the first annual notice (50 FR 19761) in which we...

  9. The Galapagos Spreading Center. Galapagos Rifts Expedition--Grades 9-12. Mid-Ocean Ridges.

    ERIC Educational Resources Information Center

    National Oceanic and Atmospheric Administration (DOC), Rockville, MD.

    This activity introduces students to the basic concept of seafloor spreading, the processes involved in creating new seafloor at a mid- ocean ridge, the Galapagos Spreading Center system, and the different types of plate motion associated with ridge segments and transform faults. The activity provides learning objectives, a list of needed…

  10. Assesing Geographic Isolation of the Galapagos Islands

    NASA Astrophysics Data System (ADS)

    Orellana, D.; Smith, F.

    2016-06-01

    The Galapagos Archipelago is one of the most important ecological spots in the planet due its unique biodiversity, active geology, and relatively well-preserved ecosystems. These characteristics are strongly based on the geographical isolation of the islands. On the one hand this isolation allowed the evolution processes that gave the islands their international fame and on the other hand it kept them from major human impacts that affected the vast majority of the Earth's surface. Galapagos' geographical isolation is therefore of mayor value, but it is rapidly diminishing due to the increase of marine and air transportation among islands and with the rest of the world. This increased accessibility implies enhanced risks for the ecological dynamics on the archipelago (e.g. increased risk of biological invasions, uncontrolled tourism growth, more water and energy consumption). Here, we introduce a general accessibility model to assess geographical isolation of the Galapagos Islands. The model aims to characterize accessibility in terms of human mobility by evaluating travel time to each point of the archipelago using all available transportation modalities. Using a multi criteria cost surface for marine and land areas, we estimated travel time for each surface unit using the fastest route and mode of transportation available while considering several friction factors such as surface type, slope, infrastructure, transfer points, legal restrictions, and physical barriers. We created maps to evaluate the isolation of different islands and places, highlighting the potential risks for several habitats and ecosystems. The model can be used for research and decision-making regarding island conservation, such as estimating spreading paths for invasive species, informing decisions on tourism management, and monitoring isolation changes of sensitive ecosystems.

  11. Smelling home: a good solution for burrow-finding in nocturnal petrels?

    PubMed

    Bonadonna, Francesco; Bretagnolle, Vincent

    2002-08-01

    Many burrowing petrels are able to return to their nests in complete darkness. The well-developed anatomy of their olfactory system and the attraction that food-related odour cues have for some petrel species suggest that olfaction may be used to recognize the burrow. In contrast, surface-nesting petrels may rely on visual cues to recognise their nest. We performed experiments on nine species of petrel (with different nesting habits) rendered anosmic either by plugging the nostrils or by injecting zinc sulphate onto the nasal epithelium. Compared with shamtreated control birds, we found that anosmia impaired nest recognition only in species that nest in burrows and that return home in darkness. Therefore, petrels showing nocturnal activity on land may rely on their sense of smell to find their burrows, while petrels showing diurnal activity or surface nesters may disregard olfactory cues in favour of visual guidance. PMID:12124375

  12. Analysis of Inter- and Intra-individual Variation in Foraging Habits of the Endangered Hawaiian Petrel Using Stables Isotopes

    NASA Astrophysics Data System (ADS)

    Morra, K. E.; Ostrom, P. H.; Wiley, A. E.; James, H. F.; Stricker, C. A.; Gandhi, H.

    2014-12-01

    Stable isotope analysis of the endangered Hawaiian petrel's (Pterodroma sandwichensis, HAPE) feathers provides otherwise intractable information regarding non-breeding season foraging habits. Adult HAPE spend 3.5-6 months at sea during the non-breeding season, at which time they sequentially molt their flight feathers. Because feathers are metabolically inert once synthesized, they capture isotopic signals while they are grown, providing an opportunity to study foraging habits over time. Here we use stable hydrogen (δD), carbon (δ13C) and nitrogen (δ15N) isotopes to assess variation in foraging habits within and between individuals, and among four breeding colonies. δD is an indicator of prevalence of fish vs. invertebrates in the diet. In one analysis, we observed large variation in feather δD (125‰), with adults from Maui and Kauai having significantly higher δD values than corresponding hatch-year birds, indicating significant dietary differences between age groups. In a second analysis, we utilized δ13C and δ15N of Hawaii, Maui and Lanai adults, values which vary with trophic level and also at the base of the food web across HAPE's foraging range, potentially revealing information about feeding location, as well as diet. Furthermore, because the sequence of molt is known, we are able to determine whether individual foraging specialization (continued use of the same foraging behavior over time) exists in this species. To do this, we analyzed two primary feathers, P1 and P6, which reflect the beginning and the middle of the non-breeding season, respectively. We did not find significant differences in δ13C or δ15N between P1 and P6, suggesting consistent foraging habits within individuals over time. This provides evidence that individual foraging specialization exists within these populations. Analysis of a secondary feather grown late in the molt sequence would further illuminate the extent of foraging specialization. Finally, δ15N differs

  13. Structure of some intact lipids of petrel stomach oils.

    PubMed

    Watts, R; Warham, J

    1976-06-01

    The stomach or proventricular oils from 16 species of petrel have been analyzed and the carbon number distributions of the wax esters, triglycerides, and diacylglyceryl ethers are reported. The wax esters have been fractionated further into less and more polar species. To determine whether any intermolecular specificity existed, carbon number distributions for each lipid class were calculated, assuming random esterifications. The tirglyceride and diacylglyceryl ether compositions observed were all found to aggree closely with those calculated. The wax esters from three petrel species were found to have greater proportions of the middle range species with carbon numbers 34-38 than calculated. However, most of the lipids examined had random structures which have been found to be characteristic of marine sources. The results in general support the belief that the oils are derived directly from dietary sources rather than synthesis by the proventricular glands. PMID:933721

  14. How quickly do albatrosses and petrels digest plastic particles?

    PubMed

    Ryan, Peter G

    2015-12-01

    Understanding how rapidly seabirds excrete or regurgitate ingested plastic items is important for their use as monitors of marine debris. van Franeker and Law (2015) inferred that fulmarine petrels excrete ∼75% of plastic particles within a month of ingestion based on decreases in the amounts of plastic in the stomachs of adult petrels moving to relatively clean environments to breed. However, similar decreases occur among resident species due to adults passing plastic loads to their chicks. The few direct measures of wear rates and retention times of persistent stomach contents suggest longer plastic residence times in most albatrosses and petrels. Residence time presumably varies with item size, type of plastic, the amount and composition of other persistent stomach contents, and the size at which items are excreted, which may vary among taxa. Accurate measures of ingested plastic retention times are needed to better understand temporal and spatial patterns in ingested plastic loads within marine organisms, especially if they are to be used as indicators of plastic pollution trends.

  15. How quickly do albatrosses and petrels digest plastic particles?

    PubMed

    Ryan, Peter G

    2015-12-01

    Understanding how rapidly seabirds excrete or regurgitate ingested plastic items is important for their use as monitors of marine debris. van Franeker and Law (2015) inferred that fulmarine petrels excrete ∼75% of plastic particles within a month of ingestion based on decreases in the amounts of plastic in the stomachs of adult petrels moving to relatively clean environments to breed. However, similar decreases occur among resident species due to adults passing plastic loads to their chicks. The few direct measures of wear rates and retention times of persistent stomach contents suggest longer plastic residence times in most albatrosses and petrels. Residence time presumably varies with item size, type of plastic, the amount and composition of other persistent stomach contents, and the size at which items are excreted, which may vary among taxa. Accurate measures of ingested plastic retention times are needed to better understand temporal and spatial patterns in ingested plastic loads within marine organisms, especially if they are to be used as indicators of plastic pollution trends. PMID:26286902

  16. Exploring conservation discourses in the Galapagos Islands: A case study of the Galapagos giant tortoises.

    PubMed

    Benitez-Capistros, Francisco; Hugé, Jean; Dahdouh-Guebas, Farid; Koedam, Nico

    2016-10-01

    Conservation discourses change rapidly both at global and local scales. To be able to capture these shifts and the relationships between humans and nature, we focused on a local and iconic conservation case: the Galapagos giant tortoises (Chelonoidis spp.). We used the Q methodology to contextualize conservation for science and decision making and to explore the multidimensionality of the conservation concept in Galapagos. The results indicate four prevailing discourses: (1) Multi-actor governance; (2) giant tortoise and ecosystems conservation; (3) community governance; and (4) market and tourism centred. These findings allow us to identify foreseeable points of disagreement, as well as areas of consensus, and to discuss the implication of the findings to address socio-ecological conservation and sustainability challenges. This can help the different involved stakeholders (managers, scientists and local communities) to the design and apply contextualized conservation actions and policies to contribute to a better sustainable management of the archipelago.

  17. Isabela, Galapagos Islands as seen from STS-59

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Space Radar Laboratory (SRL) scientists will use these photographs of Isabela in the Galapagos island chain, with the radar iamagery, to discriminate among different ages of basalt flows, and different ecosystems of shrub communities, on these equatorial volcanic islands.

  18. Isla Isabela in the western Galapagos Islands

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is an image showing part of Isla Isabela in the western Galapagos Islands. It was taken by the L-band radar in HH polarization from the Spaceborne Imaging Radar-C/X-Band Synthetic Aperature Radar on the 40th orbit of the Shuttle Endeavour. The image is centered at about .5 degrees south latitude and 91 degrees West longitude and covers an area of 75 km by 60 km. The radar incidence angle at the center of the image is about 20 degrees. This SIR-C/X-SAR image of Alcedo and Sierra Negra volcanoes shows the rougher lava flows as bright features, while ash deposits and smooth Pahoehoe lava flows appear dark. A small portion of Isla Fernandina is visible in the extreme upper left corner of the image. The Jet Propulsion Laboratory alternative photo number is P-43899.

  19. Energetics of nestling growth and parental effort in Antarctic fulmarine petrels.

    PubMed

    Hodum, Peter J; Weathers, Wesley W

    2003-07-01

    Antarctic fulmarine petrels breed in some of the coldest conditions encountered by any bird and their young grow twice as fast as predicted allometrically. To examine the energetic consequences of fast growth in a cold environment, we used the doubly labeled water technique to measure field metabolic rates of adults (three species) and different-aged nestlings (four species) of Antarctic fulmarine petrels in the Rauer Islands, East Antarctica: Antarctic fulmar Fulmarus glacialoides, Antarctic petrel Thalassoica antarctica, Cape petrel Daption capense and snow petrel Pagodroma nivea. We used our data to assess parental effort and, together with literature values on nestling growth and resting metabolic rate, to construct and partition nestling energy budgets. Nestling total energy expenditure and peak daily metabolic rate were significantly higher than predicted allometrically (33-73% and 17-66% higher, respectively), and the relative cost of growth in nestling petrels was among the highest reported for birds (54-72 kJ g(-1)). Parental effort during the nestling-feeding period was identical in adult Cape and Antarctic petrels (3.5 times basal metabolic rate, BMR), and was somewhat (but not significantly) higher in snow petrels (4.6 times BMR). These values are comparable to those of other high-latitude procellariiform birds. Thus, despite the constraints of a compressed breeding season, cold temperatures and fast-growing nestlings, adult Antarctic fulmarine petrels do not work harder than procellariid adults whose chicks grow much more slowly. Our findings suggest that obtaining sufficient food is generally not a constraint for adult fulmarine petrels and that factors operating at the tissue level limit nestling growth rate. PMID:12771162

  20. Environmental Education in the Galapagos: 2007 Report to the Charles Darwin Foundation

    ERIC Educational Resources Information Center

    Stepath, Carl M.

    2007-01-01

    Background: "Environmental education in the Galapagos: 2007 report to the Charles Darwin Foundation" is a report to the Charles Darwin Foundation (CDF) about the researchers observations about the status of environmental education in the Galapagos in 2006 and 2007. Purpose: This paper reports on environmental education in the Galapagos islands,…

  1. Evidence for nest-odour recognition in two species of diving petrel.

    PubMed

    Bonadonna, Francesco; Cunningham, Gregory B; Jouventin, Pierre; Hesters, Florence; Nevitt, Gabrielle A

    2003-10-01

    In nearly every procellariiform species, the sense of smell appears to be highly adapted for foraging at sea, but the sense of smell among the diving petrels is enigmatic. These birds forage at considerable depth and are not attracted to odour cues at sea. However, several procellariiform species have recently been shown to relocate their nesting burrows by scent, suggesting that these birds use an olfactory signature to identify the home burrow. We wanted to know whether diving petrels use smell in this way. We tested the common diving petrel Pelecanoides urinatrix and the South-Georgian diving petrel Pelecanoides georgicus to determine whether diving petrels were able to recognise their burrow by scent alone. To verify the efficacy of the method, we also tested a bird that is known to use olfaction for foraging and nest recognition, the thin-billed prion Pachyptila belcheri. In two-choice T-maze trials, we found that, for all species, individuals significantly preferred the odour of their own nest material to that of a conspecific. Our findings strongly suggest that an individual-specific odour provides an olfactory signature that allows burrowing petrels to recognize their own burrow. Since this ability seems to be well developed in diving petrels, our data further implicate a novel adaptation for olfaction in these two species that have been presumed to lack a well-developed sense of smell. PMID:12966063

  2. Species, gender, and identity: cracking petrels' sociochemical code.

    PubMed

    Mardon, Jérôme; Saunders, Sandra M; Anderson, Marti J; Couchoux, Charline; Bonadonna, Francesco

    2010-05-01

    Avian chemosignaling remains relatively unexplored, but its potential importance in birds' social behaviors is becoming recognized. Procellariiform seabirds provide particularly appropriate models for investigating these topics as they possess a well-developed olfactory system and unequalled associated capabilities. We present here results from a detailed chemical examination of the uropygial secretions (the main source of avian exogenous chemicals) from 2 petrel species, Antarctic prions and blue petrels. Using gas chromatography-mass spectrometry techniques and recently developed multivariate tools, we demonstrate that the secretions contain critical socioecological information such as species, gender, and individual identity. Importantly, these chemosignals correlate with some of the birds' olfactory behaviors demonstrated in the field. The molecules found to be associated with social information were essentially large unsaturated compounds, suggesting that these may be precursors of, or correlates to the actual airborne signals. Although the species-specific chemosignal may be involved in interspecific competition at the breeding grounds, the role of the sexually specific chemosignal remains unclear. The existence of individually specific signals (i.e., chemical signatures) in these birds has important implications for processes such as individual recognition and genetically based mate choice already suspected for this group. Our results open promising avenues of research for the study of avian chemical communication. PMID:20190009

  3. Metabolic cost of incubation in the Laysan albatross and Bonin petrel.

    PubMed

    Grant, G S; Whittow, G C

    1983-01-01

    1. Oxygen consumption and carbon dioxide production were measured in resting and incubating Laysan albatrosses and Bonin petrels on Midway Atoll in the north central Pacific Ocean. 2. Incubation metabolism within the thermal neutral zone is less than or equal to resting metabolism in the albatross and petrel. 3. The respiratory quotients (0.64-0.72) during the long fasts indicate fat metabolism. 4. The estimated fractional water content of the albatross and petrel do not change during incubation fasts because water loss is balanced by metabolic water production. PMID:6130887

  4. Metabolic cost of incubation in the Laysan albatross and Bonin petrel.

    PubMed

    Grant, G S; Whittow, G C

    1983-01-01

    1. Oxygen consumption and carbon dioxide production were measured in resting and incubating Laysan albatrosses and Bonin petrels on Midway Atoll in the north central Pacific Ocean. 2. Incubation metabolism within the thermal neutral zone is less than or equal to resting metabolism in the albatross and petrel. 3. The respiratory quotients (0.64-0.72) during the long fasts indicate fat metabolism. 4. The estimated fractional water content of the albatross and petrel do not change during incubation fasts because water loss is balanced by metabolic water production.

  5. Counter-rotating microplates at the Galapagos triple junction.

    PubMed

    Klein, Emily M; Smith, Deborah K; Williams, Clare M; Schouten, Hans

    2005-02-24

    An 'incipient' spreading centre east of (and orthogonal to) the East Pacific Rise at 2 degrees 40' N has been identified as forming a portion of the northern boundary of the Galapagos microplate. This spreading centre was described as a slowly diverging, westward propagating rift, tapering towards the East Pacific Rise. Here we present evidence that the 'incipient rift' has also rifted towards the east and opens anticlockwise about a pivot at its eastern end. The 'incipient rift' then bounds a second microplate, north of the clockwise-rotating Galapagos microplate. The Galapagos triple junction region, in the eastern equatorial Pacific Ocean, thus consists of two counter-rotating microplates partly separated by the Hess Deep rift. Our kinematic solution for microplate motion relative to the major plates indicates that the two counter-rotating microplates may be treated as rigid blocks driven by drag on the microplates' edges3.

  6. UAV Monitoring for Enviromental Management in Galapagos Islands

    NASA Astrophysics Data System (ADS)

    Ballari, D.; Orellana, D.; Acosta, E.; Espinoza, A.; Morocho, V.

    2016-06-01

    In the Galapagos Islands, where 97% of the territory is protected and ecosystem dynamics are highly vulnerable, timely and accurate information is key for decision making. An appropriate monitoring system must meet two key features: on one hand, being able to capture information in a systematic and regular basis, and on the other hand, to quickly gather information on demand for specific purposes. The lack of such a system for geographic information limits the ability of Galapagos Islands' institutions to evaluate and act upon environmental threats such as invasive species spread and vegetation degradation. In this context, the use of UAVs (unmanned aerial vehicles) for capturing georeferenced images is a promising technology for environmental monitoring and management. This paper explores the potential of UAV images for monitoring degradation of littoral vegetation in Puerto Villamil (Isabela Island, Galapagos, Ecuador). Imagery was captured using two camera types: Red Green Blue (RGB) and Infrarred Red Green (NIR). First, vegetation presence was identified through NDVI. Second, object-based classification was carried out for characterization of vegetation vigor. Results demonstrates the feasibility of UAV technology for base-line studies and monitoring on the amount and vigorousness of littoral vegetation in the Galapagos Islands. It is also showed that UAV images are not only useful for visual interpretation and object delineation, but also to timely produce useful thematic information for environmental management.

  7. The Galapagos Islands: Darwin and Modern Conservation Stories

    ERIC Educational Resources Information Center

    Burr, Susan

    2010-01-01

    The author visited the Galapagos Islands in 2009 and here looks at their biodiversity through pictures taken then. The diverse habitats of the Islands are reflected in the great diversity of flora and fauna found on them, with many species endemic to the Islands. The stories of the land iguanas, control of introduced species and the giant…

  8. Seroprevalence of malarial antibodies in Galapagos penguins (Spheniscus mendiculus).

    PubMed

    Palmer, Jamie L; McCutchan, Thomas F; Vargas, F Hernan; Deem, Sharon L; Cruz, Marilyn; Hartman, Daniel A; Parker, Patricia G

    2013-10-01

    A parasite species of the genus Plasmodium has recently been documented in the endangered Galapagos penguin (Spheniscus mendiculus). Avian malaria causes high mortality in several species after initial exposure and there is great concern for the conservation of the endemic Galapagos penguin. Using a Plasmodium spp. circumsporozoite protein antigen, we standardized an enzyme-linked immunosorbent assay to test the level of exposure in this small population, as indicated by seroprevalence. Sera from adult and juvenile Galapagos penguins collected between 2004 and 2009 on the Galapagos archipelago were tested for the presence of anti- Plasmodium spp. antibodies. Penguins were also tested for the prevalence of avian malaria parasite DNA using a polymerase chain reaction (PCR) screening. Total seroprevalence of malarial antibodies in this sample group was 97.2%, which suggests high exposure to the parasite and low Plasmodium-induced mortality. However, total prevalence of Plasmodium parasite DNA by PCR screening was 9.2%, and this suggests that parasite prevalence may be under-detected through PCR screening. Multiple detection methods may be necessary to measure the real extent of Plasmodium exposure on the archipelago.

  9. Deep-sea primary production at the Galapagos hydrothermal vents

    SciTech Connect

    Karl, D.M.; Wirsen, C.O.; Jannasch, H.W.

    1980-03-21

    Dense animal populations surrounding recently discovered hydrothermal vents at the Galapagos Rift sea-floor spreading center, 2550 meters deep, are probably sustained by microbial primary production. Energy in the form of geothermically reduced sulfur compounds emitted from the vents is liberated during oxidation and used for the reduction of carbon dioxide to organic matter by chemosynthetic bacteria.

  10. Galapagos III World Evolution Summit: why evolution matters

    PubMed Central

    Paz-y-Miño-C, Guillermo; Espinosa, Avelina

    2016-01-01

    There is no place on Earth like the Galapagos Islands and no better destination to discuss the reality of evolution. Under the theme ‘Why Does Evolution Matter’, the University San Francisco of Quito (USFQ), Ecuador, and its Galapagos Institute for the Arts and Sciences (GAIAS), organized the III World Evolution Summit in San Cristóbal Island. The 200-attendee meeting took place on 1 to 5 June 2013; it included 12 keynote speakers, 20 oral presentations by international scholars, and 31 posters by faculty, postdocs, and graduate and undergraduate students. The Summit encompassed five sessions: evolution and society, pre-cellular evolution and the RNA world, behavior and environment, genome, and microbes and diseases. USFQ and GAIAS launched officially the Lynn Margulis Center for Evolutionary Biology and showcased the Galapagos Science Center, in San Cristóbal, an impressive research facility conceptualized in partnership with the University of North Carolina at Chapel Hill, USA. USFQ and GAIAS excelled at managing the conference with exceptional vision and at highlighting the relevance of Galapagos in the history of modern evolutionary thinking; Charles Darwin’s visit to this volcanic archipelago in 1835 unfolded unprecedented scientific interest in what today is a matchless World Heritage. PMID:26925190

  11. At-Sea Distribution and Prey Selection of Antarctic Petrels and Commercial Krill Fisheries

    PubMed Central

    Descamps, Sébastien; Tarroux, Arnaud; Cherel, Yves; Delord, Karine; Godø, Olaf Rune; Kato, Akiko; Krafft, Bjørn A.; Lorentsen, Svein-Håkon; Ropert-Coudert, Yan; Skaret, Georg; Varpe, Øystein

    2016-01-01

    Commercial fisheries may impact marine ecosystems and affect populations of predators like seabirds. In the Southern Ocean, there is an extensive fishery for Antarctic krill Euphausia superba that is projected to increase further. Comparing distribution and prey selection of fishing operations versus predators is needed to predict fishery-related impacts on krill-dependent predators. In this context, it is important to consider not only predators breeding near the fishing grounds but also the ones breeding far away and that disperse during the non-breeding season where they may interact with fisheries. In this study, we first quantified the overlap between the distribution of the Antarctic krill fisheries and the distribution of a krill dependent seabird, the Antarctic petrel Thalassoica antarctica, during both the breeding and non-breeding season. We tracked birds from the world biggest Antarctic petrel colony (Svarthamaren, Dronning Maud Land), located >1000 km from the main fishing areas, during three consecutive seasons. The overall spatial overlap between krill fisheries and Antarctic petrels was limited but varied greatly among and within years, and was high in some periods during the non-breeding season. In a second step, we described the length frequency distribution of Antarctic krill consumed by Antarctic petrels, and compared this with results from fisheries, as well as from diet studies in other krill predators. Krill taken by Antarctic petrels did not differ in size from that taken by trawls or from krill taken by most Antarctic krill predators. Selectivity for specific Antarctic krill stages seems generally low in Antarctic predators. Overall, our results show that competition between Antarctic petrels and krill fisheries is currently likely negligible. However, if krill fisheries are to increase in the future, competition with the Antarctic petrel may occur, even with birds breeding thousands of kilometers away. PMID:27533327

  12. At-Sea Distribution and Prey Selection of Antarctic Petrels and Commercial Krill Fisheries.

    PubMed

    Descamps, Sébastien; Tarroux, Arnaud; Cherel, Yves; Delord, Karine; Godø, Olaf Rune; Kato, Akiko; Krafft, Bjørn A; Lorentsen, Svein-Håkon; Ropert-Coudert, Yan; Skaret, Georg; Varpe, Øystein

    2016-01-01

    Commercial fisheries may impact marine ecosystems and affect populations of predators like seabirds. In the Southern Ocean, there is an extensive fishery for Antarctic krill Euphausia superba that is projected to increase further. Comparing distribution and prey selection of fishing operations versus predators is needed to predict fishery-related impacts on krill-dependent predators. In this context, it is important to consider not only predators breeding near the fishing grounds but also the ones breeding far away and that disperse during the non-breeding season where they may interact with fisheries. In this study, we first quantified the overlap between the distribution of the Antarctic krill fisheries and the distribution of a krill dependent seabird, the Antarctic petrel Thalassoica antarctica, during both the breeding and non-breeding season. We tracked birds from the world biggest Antarctic petrel colony (Svarthamaren, Dronning Maud Land), located >1000 km from the main fishing areas, during three consecutive seasons. The overall spatial overlap between krill fisheries and Antarctic petrels was limited but varied greatly among and within years, and was high in some periods during the non-breeding season. In a second step, we described the length frequency distribution of Antarctic krill consumed by Antarctic petrels, and compared this with results from fisheries, as well as from diet studies in other krill predators. Krill taken by Antarctic petrels did not differ in size from that taken by trawls or from krill taken by most Antarctic krill predators. Selectivity for specific Antarctic krill stages seems generally low in Antarctic predators. Overall, our results show that competition between Antarctic petrels and krill fisheries is currently likely negligible. However, if krill fisheries are to increase in the future, competition with the Antarctic petrel may occur, even with birds breeding thousands of kilometers away. PMID:27533327

  13. At-Sea Distribution and Prey Selection of Antarctic Petrels and Commercial Krill Fisheries.

    PubMed

    Descamps, Sébastien; Tarroux, Arnaud; Cherel, Yves; Delord, Karine; Godø, Olaf Rune; Kato, Akiko; Krafft, Bjørn A; Lorentsen, Svein-Håkon; Ropert-Coudert, Yan; Skaret, Georg; Varpe, Øystein

    2016-01-01

    Commercial fisheries may impact marine ecosystems and affect populations of predators like seabirds. In the Southern Ocean, there is an extensive fishery for Antarctic krill Euphausia superba that is projected to increase further. Comparing distribution and prey selection of fishing operations versus predators is needed to predict fishery-related impacts on krill-dependent predators. In this context, it is important to consider not only predators breeding near the fishing grounds but also the ones breeding far away and that disperse during the non-breeding season where they may interact with fisheries. In this study, we first quantified the overlap between the distribution of the Antarctic krill fisheries and the distribution of a krill dependent seabird, the Antarctic petrel Thalassoica antarctica, during both the breeding and non-breeding season. We tracked birds from the world biggest Antarctic petrel colony (Svarthamaren, Dronning Maud Land), located >1000 km from the main fishing areas, during three consecutive seasons. The overall spatial overlap between krill fisheries and Antarctic petrels was limited but varied greatly among and within years, and was high in some periods during the non-breeding season. In a second step, we described the length frequency distribution of Antarctic krill consumed by Antarctic petrels, and compared this with results from fisheries, as well as from diet studies in other krill predators. Krill taken by Antarctic petrels did not differ in size from that taken by trawls or from krill taken by most Antarctic krill predators. Selectivity for specific Antarctic krill stages seems generally low in Antarctic predators. Overall, our results show that competition between Antarctic petrels and krill fisheries is currently likely negligible. However, if krill fisheries are to increase in the future, competition with the Antarctic petrel may occur, even with birds breeding thousands of kilometers away.

  14. Crustal thickness variations along the Galapagos Spreading Center west of the Galapagos hotspot

    NASA Astrophysics Data System (ADS)

    Ito, G.; Canales, J.; Detrick, R.; Sinton, J.

    2001-12-01

    Wide-angle seismic refraction and multi-channel seismic (MCS) reflection data reveal crustal thickness variations along the Galapagos Spreading Center (GSC) 98° -91.5° W. Travel-time and amplitude modeling of wide-angle refraction data constrain the seismic velocity structure and thickness of mature crust along three ridge-parallel profiles centered at 96.8° W, 94.25° W, and 92.2° W. In addition, MCS data along ridge-parallel, off-axis profiles image reflections from the base of the crust (Moho) west of 95.5° W. Where MCS and refraction data coincide, zero-offset arrival times of Moho reflections agree closely between the two data sets. To compute crustal thickness from the Moho reflections, we interpolate velocity-depth profiles between the refraction sites using cubic splines. We observe the thinnest crust (5.6 km) along the GSC near 96.8° W. To the east, the crust thickens gradually toward the Galapagos hotspot (along-axis gradient ~0.01 km/km) to 5.9 km near 94.25° W. Near the 95.5° W-propagating rift tip we do not resolve a local thinning of the crust that would otherwise be attributed to a "propagator effect". East of 94.25° W the GSC crust thickens more rapidly (along-axis gradient ~0.05 km/km), reaching a thickness of 8 km at our closest approach to the hotspot near 91.5° W. Constraints on along-axis crustal thickness variations are valuable in understanding processes of mantle melting as well as factors leading to changes in ridge morphology. The rapid thickening of the GSC crust east of ~94° W suggests that the hottest and/or most rapidly upwelling mantle is confined to a distance of ~400 km from the center of the Galapagos hotspot. West of ~94° W the hotspot effect on crustal thickness is minimal though gravity and bathymetry anomalies extend 200-400 km further west [Canales et al. this meeting]. A prominent axial valley is sustained west of ~95° W where crustal thickness is <5.9 km. East of ~94° W, where crustal thickness is >6 km, the

  15. Changes in plasma hormone levels correlate with fledging in nestling Leach's storm-petrels.

    PubMed

    Kozlowski, Corinne P; Mauck, Robert A; O'Reilly, Kathleen M; Philipsborn, Jon; Ricklefs, Robert E

    2010-10-01

    Leach's storm-petrels accumulate large amounts of body mass throughout the nestling period. Approximately 4days before fledging, nestlings weigh 50-100% more than adults. In order to shed this excess mass, nestlings engage in behavioral anorexia, and leave the burrow when they are light enough to fly. During this prefledging period, we measured several plasma hormones (corticosterone, thyroxine, and testosterone) to determine whether the behavioral changes associated with fledging are correlated with endocrine changes. In several species, including petrels, corticosterone levels are known to increase near fledging. Reduced food consumption has been shown to elevate corticosterone levels and decrease thyroxine levels in nestling birds. In nestling storm-petrels, levels of both corticosterone and thyroxine increased. Storm-petrels were found to secrete measurable levels of testosterone, but levels did not change during the prefledging period. Increased corticosterone levels might be part of an endocrine signal that initiates changes in feeding behavior, or may result from reduced food intake. Elevated thyroxine levels may be related to metabolic changes involved in mass loss. Future experimental work is needed to ascertain whether the described endocrine changes are responsible for, or result from, prefledging changes in petrel feeding behavior. PMID:20688060

  16. Contrasting movement strategies among juvenile albatrosses and petrels

    PubMed Central

    de Grissac, Sophie; Börger, Luca; Guitteaud, Audrey; Weimerskirch, Henri

    2016-01-01

    Animal movement is a fundamental eco-evolutionary process yet the behaviour of juvenile animals is largely unknown for many species, especially for soaring seabirds which can range widely over the oceans at low cost. We present an unprecedented dataset of 98 juvenile albatrosses and petrels (nine species), tracked for the first three months after independence. There was a startling diversity within and among species in the type and scale of post-natal movement strategies, ranging from area-restricted to nomadic patterns. Spatial scales were clustered in three groups that ranged from <3000 km to >6000 km from the natal nest. In seven of the nine species, the orientation of flight paths and other movement statistics showed strong similarities between juveniles and adults, providing evidence for innate orientation abilities. Our results have implications for understanding the development of foraging behaviour in naïve individuals and the evolution of life history traits such as survival, lifespan and breeding strategy. PMID:27189182

  17. Linking the Galapagos hotspot and the Caribbean Plateau

    NASA Astrophysics Data System (ADS)

    Nerlich, Rainer; Clark, Stuart R.; Bunge, Hans-Peter

    2014-05-01

    Wide agreement exists that the Caribbean plate has a Pacific origin and that parts of it depict an igneous Plateau of up to 20 km thick crust. However, the origin of this thickened crust remains debated. One of the first suggestions for its origin was the arrival of a plume, whose remnant might be the Galapagos hotspot. More recently, it has been argued that reconstruction models predicted the Galapagos hotspot a thousand or more kilometres away from the Caribbean plate at the time of Plateau formation (~88 ?? 94 Ma). These authors primarily relied on the Caribbean Plateau moving into its present position relative to the Americas only in the last few million years. Secondarily, the authors assumed that the hotspot was fixed in an Indian-Atlantic hotspot reference frame. Here, we explore the idea that the Plateau moved into position around the time of the initiation of convergence between the North and South America, about 54.5 Ma. In addition, we adopt a fixed Pacific hotspot reference frame and compare our results to the recently developed Global Moving Hotspot Reference Frame. We show that both frames lead to good correlations between the paleo-positions of the Caribbean Plate and the Galapagos hotspot. As this result is consistent with abundant geochemical evidence that lends support for both a plume origin as well as the similarity between the Galapagos hotspot and rocks from the Plateau itself, we argue that alternative mechanisms to explain the thickened crust of the Caribbean Plateau are unnecessary. Additionally, based on our new plate reconstruction model, we present an age distribution of the lithosphere underneath the thickened crust of the Caribbean Plateau that has remained speculative until now.

  18. Lithospheric structure and compensation mechanisms of the Galapagos Archipelago

    NASA Astrophysics Data System (ADS)

    Feighner, Mark A.; Richards, Mark A.

    1994-04-01

    Volcanic islands of the Galapagos Archipelago are the most recent subaerial expression of the Galapagos hotspot. These islands and numerous seamounts are constructed mainly upon a broad volcanic platform that overlies very young (less than 10 m.y.) oceanic lithosphere just south of the active Galapagos Spreading Center. The 91 deg W fracture zone crosses the platform and creates an estimated 5-m.y. age discontinuity in the lithosphere. Major tectonic features of the Galapagos include an unusually broad distribution of volcanic centers, pronounced structural trends such as the NW-SE Wolf-Darwin Lineament (WDL), and a steep escarpment along the western and southern margins of the archipelago. We use shipboard gravity and bathymetry data along with Geosat geoid data to explain the tectonic and structural evolution of the Galapagos region. We model the gravity anomalies using a variety of compensation models, including Airy isostasy, continuous elastic flexure of the lithosphere, and an elastic plate with embedded weaknesses, and we infer significant lithospheric strength variations across the archipelago. The outboard parts of the southern and western escarpment are flexurally supported with an effective elastic thickness of approximately 12 km. This area includes the large shield volcanoes of Fernandina and Isabela Islands, where the lithosphere regionally supports these volcanic loads. The central platform is weaker, with an elastic thickness of 6 km or less, and close to Airy isostasy. The greatest depths to the Moho are located beneath eastern Isabela Island and the central platform. Thinner lithosphere in this region may account for the broad distribution of volcanoes, the extended period of eruption of the central volcanoes, and their reduced size. The transition from strong to weak lithosphere along the southern escarpment appears to be abrupt, within the resolution of our models, and can be best represented by a free end or faultlike discontinuity. Also

  19. Avian cholera in a southern giant petrel (Macronectes giganteus) from Antarctica.

    PubMed

    Leotta, G A; Rivas, M; Chinen, I; Vigo, G B; Moredo, F A; Coria, N; Wolcott, M J

    2003-07-01

    A southern giant petrel (Macronectes giganteus) was found dead at Potter Peninsula, King George Island, South Shetland, Antarctica. The adult male was discovered approximately 48 hr after death. Macroscopic and microscopic lesions were compatible with avian cholera and the bacterium Pasteurella multocida subsp. gallicida, serotype A1 was isolated from lung, heart, liver, pericardial sac, and air sacs. In addition, Escherichia coli was isolated from pericardial sac and air sacs. This is the first known report of avian cholera in a southern giant petrel in Antarctica. PMID:14567240

  20. Galapagos and Easter: A Tale of Two Hotspots

    NASA Astrophysics Data System (ADS)

    Harpp, K.; Hall, P. S.; Jackson, M. G.

    2012-12-01

    Spatial asymmetry in the isotopic composition of volcanic rocks has been identified at several Pacific hotspots, including Hawaii, the Marquesas, and Samoa (Weis, 2011; Huang et al., 2011); the volcanoes are arranged in two chains that define distinct, sub-parallel fields in isotopic space. For these hotspots, lavas from the northern chains have a more depleted signature (higher ɛNd, lower 87Sr/86Sr, lower 208Pb*/206Pb*) than the corresponding southern chains. All 3 hotspots are located near the northern margin of the Large Low Shear Velocity Province (LLSVP) beneath the Pacific. Previous workers have proposed that the asymmetry may reflect bilateral compositional zonation in the plume created by an azimuthal distribution of heterogeneities about the base of the plume conduit, related to material in the LLSVP. This distribution is preserved in filaments from the lower mantle (e.g., Farnetani and Hofmann, 2009). Recently, Payne et al. (in press) showed that rocks from the Societies have an isotopic asymmetry that is the mirror image of Hawaii, with the northern lavas enriched relative to the southern chain. This is consistent with the Societies hotspot's location near the southern, rather than the northern margin of the LLSVP. We present data from two additional hotspots that exhibit spatial asymmetry in the isotopic characteristics of their lavas: the Galapagos and Easter hotspots, both on the Nazca Plate. Despite lacking two distinct volcanic chains, Galapagos lavas define a pattern similar to Hawaii, with enriched isotopic signatures in the southern and western archipelago and more depleted material in the north and east; the boundary dividing the compositional fields defines a NW-SE line parallel to the edge of the LLSVP. In contrast, the Easter Island chain resembles the Societies, in that the enriched lavas are erupted from the northern volcanoes, a mirror image of the Galapagos and coincident with the southern boundary of the LLSVP. Several important

  1. Polybrominated diphenyl ethers in fat samples from White-chinned Petrels (Procellaria aequinoctialis) and Spectacled Petrels (P. conspicillata) off southern Brazil.

    PubMed

    Cipro, Caio V Z; Colabuono, Fernanda I; Taniguchi, Satie; Montone, Rosalinda C

    2013-12-15

    Polybrominated diphenyl ethers (PBDEs) have been gaining much visibility in environmental chemical studies due to their similarity to PCBs and growing reports of harmful effects. The fact that these contaminants have not yet undergone bans or restrictions on the global level underscores the need for data on their occurrence. In the present study, fat samples from 26 White-chinned Petrels (Procellaria aequinoctialis) and 3 Spectacled Petrels (P. conspicillata) collected dead ashore or as bycatch of longline fisheries in southern Brazil were analyzed to determine concentrations of seven congeners (IUPAC #28, 47, 99, 100, 153, 154 and 183). Concentrations of ΣPBDEs ranged from not detectable to 72.70 ng g(-1) (wet weight), comparatively lower than concentrations reported for seabird samples in northern hemisphere. The most detected congeners were 153, 154 and 183. This pattern is close to that previously reported for birds of the same group, but not those from the same region. PMID:24143957

  2. Hippocampal volume is related to complexity of nesting habitat in Leach's storm-petrel, a nocturnal procellariiform seabird.

    PubMed

    Abbott, M L; Walsh, C J; Storey, A E; Stenhouse, I J; Harley, C W

    1999-01-01

    The hippocampal and telencephalon volumes of the nocturnal Leach's storm-petrel (Oceanodroma leucorhoa, n = 15) were compared with published data for food-storing and non-storing Passerines. The hippocampus to telencephalon ratio of Leach's storm-petrels is intermediate between food-storing and non-storing birds. Leach's storm-petrels taken from nesting burrows in wooded habitat had a larger relative hippocampal volume than those taken from burrows in an open meadow. Relative olfactory volume did not differ between woods and open-nesting storm-petrels. The larger relative hippocampal volume of storm-petrels may be associated with increased spatial demands of returning to their nests at night in the darker, more navigationally complex woods. It is not known whether the larger hippocampus in storm-petrels from the woods is due to selection on different subpopulations or whether experience in a more complex environment results in greater hippocampal volume. Hippocampal volume from the brain of one diurnal Procellariiforme, the northern fulmar (Fulmaris glacialis), fell within the range of non-storing species, which supports the view that hippocampal enlargement in the storm-petrel is related to the spatial demand of returning to the nest at night. PMID:10473903

  3. Effectiveness of emetics to study plastic ingestion by Leach's Storm-petrels (Oceanodroma leucorhoa).

    PubMed

    Bond, Alexander L; Lavers, Jennifer L

    2013-05-15

    Most plastic ingestion studies rely on dissection of dead birds, which are found opportunistically, and may be biased. We used Leach's Storm-petrels (Oceanodroma leucorhoa) in Newfoundland to study the effect of dose volume, and the efficacy of emesis using syrup of ipecac as an emetic. Ipecac is a safe method of non-lethally sampling stomach contents, and recovered all ingested plastic. Almost half the storm-petrels sampled had ingested plastic, ranging from 0 to 17 pieces, and weighing 0.2-16.9 mg. Using the Ecological Quality Objective for Northern Fulmars, adjusted for storm-petrels smaller size, 43% exceeded the threshold of 0.0077 g of plastic. Many adult seabirds offload plastic to their offspring, so storm-petrel chicks likely experience a higher plastic burden than their parents. The ability to study plastic ingestion non-lethally allows researchers to move from opportunistic and haphazard sampling to hypothesis-driven studies on a wider range of taxa and age classes.

  4. Specimens and probable breeding activity of the band-rumped storm-petrel on Hawaii

    USGS Publications Warehouse

    Banko, W.E.; Banko, P.C.; David, R.E.

    1991-01-01

    Specimens (a downy fledgling and a hatch-year juvenile) and nocturnal calling of the Band-rumped Storm-Petrel (Oceanodroma custro) are evidence that this rare seabird breeds on the island of Hawaii. Nocturnal calling over land and sightings near the coast indicate that populations nest on the southwest rift and possibly the upper western slope of Mauna Loa.

  5. Effectiveness of emetics to study plastic ingestion by Leach's Storm-petrels (Oceanodroma leucorhoa).

    PubMed

    Bond, Alexander L; Lavers, Jennifer L

    2013-05-15

    Most plastic ingestion studies rely on dissection of dead birds, which are found opportunistically, and may be biased. We used Leach's Storm-petrels (Oceanodroma leucorhoa) in Newfoundland to study the effect of dose volume, and the efficacy of emesis using syrup of ipecac as an emetic. Ipecac is a safe method of non-lethally sampling stomach contents, and recovered all ingested plastic. Almost half the storm-petrels sampled had ingested plastic, ranging from 0 to 17 pieces, and weighing 0.2-16.9 mg. Using the Ecological Quality Objective for Northern Fulmars, adjusted for storm-petrels smaller size, 43% exceeded the threshold of 0.0077 g of plastic. Many adult seabirds offload plastic to their offspring, so storm-petrel chicks likely experience a higher plastic burden than their parents. The ability to study plastic ingestion non-lethally allows researchers to move from opportunistic and haphazard sampling to hypothesis-driven studies on a wider range of taxa and age classes. PMID:23507234

  6. Phylogenetic affinities of the Fregetta storm-petrels are not black and white.

    PubMed

    Robertson, Bruce C; Stephenson, Brent M; Ronconi, Robert A; Goldstien, Sharyn J; Shepherd, Lara; Tennyson, Alan; Carlile, Nicholas; Ryan, Peter G

    2016-04-01

    The Fregetta storm-petrels generally are regarded to comprise two species: black-bellied storm-petrels F. tropica (monotypic) breed at Antarctic and sub-Antarctic islands (46-63°S), and white-bellied storm-petrels F. grallaria breed at south temperate islands (28-37°S), with four recognized subspecies. Confusion surrounds the status of birds at Gough Island (40°S), central South Atlantic, which have been attributed usually to a white-bellied form of black-bellied storm-petrel F. t. melanoleuca. We use cytochrome b and nuclear β-fibrinogen gene sequences to show that F. t. melanoleuca are present during the breeding season at Gough and islands in the nearby Tristan da Cunha archipelago (37°S), exhibiting limited divergence from F. t. tropica. We also show that there is greater diversity among F. grallaria populations, with eastern South Pacific F. g. segethi and F. g. titan differing by c. 0.011, and both differing from western South Pacific nominate F. g. grallaria by c. 0.059. The Tristan archipelago supports a population of F. grallaria closely allied to the nominate form, as well as a distinct form identified as F. g. leucogaster. Further research is needed to assess how F. grallaria and F. tropica segregate in sympatry at Tristan and Gough, and why this is the only location where both species have white-bellies. PMID:26804817

  7. Phylogenetic affinities of the Fregetta storm-petrels are not black and white.

    PubMed

    Robertson, Bruce C; Stephenson, Brent M; Ronconi, Robert A; Goldstien, Sharyn J; Shepherd, Lara; Tennyson, Alan; Carlile, Nicholas; Ryan, Peter G

    2016-04-01

    The Fregetta storm-petrels generally are regarded to comprise two species: black-bellied storm-petrels F. tropica (monotypic) breed at Antarctic and sub-Antarctic islands (46-63°S), and white-bellied storm-petrels F. grallaria breed at south temperate islands (28-37°S), with four recognized subspecies. Confusion surrounds the status of birds at Gough Island (40°S), central South Atlantic, which have been attributed usually to a white-bellied form of black-bellied storm-petrel F. t. melanoleuca. We use cytochrome b and nuclear β-fibrinogen gene sequences to show that F. t. melanoleuca are present during the breeding season at Gough and islands in the nearby Tristan da Cunha archipelago (37°S), exhibiting limited divergence from F. t. tropica. We also show that there is greater diversity among F. grallaria populations, with eastern South Pacific F. g. segethi and F. g. titan differing by c. 0.011, and both differing from western South Pacific nominate F. g. grallaria by c. 0.059. The Tristan archipelago supports a population of F. grallaria closely allied to the nominate form, as well as a distinct form identified as F. g. leucogaster. Further research is needed to assess how F. grallaria and F. tropica segregate in sympatry at Tristan and Gough, and why this is the only location where both species have white-bellies.

  8. 110 Years of Avipoxvirus in the Galapagos Islands

    PubMed Central

    Parker, Patricia G.; Buckles, Elizabeth L.; Farrington, Heather; Petren, Kenneth; Whiteman, Noah K.; Ricklefs, Robert E.; Bollmer, Jennifer L.; Jiménez-Uzcátegui, Gustavo

    2011-01-01

    The role of disease in regulating populations is controversial, partly owing to the absence of good disease records in historic wildlife populations. We examined birds collected in the Galapagos Islands between 1891 and 1906 that are currently held at the California Academy of Sciences and the Zoologisches Staatssammlung Muenchen, including 3973 specimens representing species from two well-studied families of endemic passerine birds: finches and mockingbirds. Beginning with samples collected in 1899, we observed cutaneous lesions consistent with Avipoxvirus on 226 (6.3%) specimens. Histopathology and viral genotyping of 59 candidate tissue samples from six islands showed that 21 (35.6%) were positive for Avipoxvirus, while alternative diagnoses for some of those testing negative by both methods were feather follicle cysts, non-specific dermatitis, or post mortem fungal colonization. Positive specimens were significantly nonrandomly distributed among islands both for mockingbirds (San Cristobal vs. Espanola, Santa Fe and Santa Cruz) and for finches (San Cristobal and Isabela vs. Santa Cruz and Floreana), and overall highly significantly distributed toward islands that were inhabited by humans (San Cristobal, Isabela, Floreana) vs. uninhabited at the time of collection (Santa Cruz, Santa Fe, Espanola), with only one positive individual on an uninhabited island. Eleven of the positive specimens sequenced successfully were identical at four diagnostic sites to the two canarypox variants previously described in contemporary Galapagos passerines. We conclude that this virus was introduced late in 1890′s and was dispersed among islands by a variety of mechanisms, including regular human movements among colonized islands. At present, this disease represents an ongoing threat to the birds on the Galapagos Islands. PMID:21249151

  9. Allometric and temporal scaling of movement characteristics in Galapagos tortoises.

    PubMed

    Bastille-Rousseau, Guillaume; Yackulic, Charles B; Frair, Jacqueline L; Cabrera, Freddy; Blake, Stephen

    2016-09-01

    Understanding how individual movement scales with body size is of fundamental importance in predicting ecological relationships for diverse species. One-dimensional movement metrics scale consistently with body size yet vary over different temporal scales. Knowing how temporal scale influences the relationship between animal body size and movement would better inform hypotheses about the efficiency of foraging behaviour, the ontogeny of energy budgets, and numerous life-history trade-offs. We investigated how the temporal scaling of allometric patterns in movement varies over the course of a year, specifically during periods of motivated (directional and fast movement) and unmotivated (stationary and tortuous movement) behaviour. We focused on a recently diverged group of species that displays wide variation in movement behaviour - giant Galapagos tortoises (Chelonoidis spp.) - to test how movement metrics estimated on a monthly basis scaled with body size. We used state-space modelling to estimate seven different movement metrics of Galapagos tortoises. We used log-log regression of the power law to evaluate allometric scaling for these movement metrics and contrasted relationships by species and sex. Allometric scaling of movement was more apparent during motivated periods of movement. During this period, allometry was revealed at multiple temporal intervals (hourly, daily and monthly), with values observed at daily and monthly intervals corresponding most closely to the expected one-fourth scaling coefficient, albeit with wide credible intervals. We further detected differences in the magnitude of scaling among taxa uncoupled from observed differences in the temporal structuring of their movement rates. Our results indicate that the definition of temporal scales is fundamental to the detection of allometry of movement and should be given more attention in movement studies. Our approach not only provides new conceptual insights into temporal attributes in one

  10. 110 years of Avipoxvirus in the Galapagos Islands.

    PubMed

    Parker, Patricia G; Buckles, Elizabeth L; Farrington, Heather; Petren, Kenneth; Whiteman, Noah K; Ricklefs, Robert E; Bollmer, Jennifer L; Jiménez-Uzcátegui, Gustavo

    2011-01-13

    The role of disease in regulating populations is controversial, partly owing to the absence of good disease records in historic wildlife populations. We examined birds collected in the Galapagos Islands between 1891 and 1906 that are currently held at the California Academy of Sciences and the Zoologisches Staatssammlung Muenchen, including 3973 specimens representing species from two well-studied families of endemic passerine birds: finches and mockingbirds. Beginning with samples collected in 1899, we observed cutaneous lesions consistent with Avipoxvirus on 226 (6.3%) specimens. Histopathology and viral genotyping of 59 candidate tissue samples from six islands showed that 21 (35.6%) were positive for Avipoxvirus, while alternative diagnoses for some of those testing negative by both methods were feather follicle cysts, non-specific dermatitis, or post mortem fungal colonization. Positive specimens were significantly nonrandomly distributed among islands both for mockingbirds (San Cristobal vs. Espanola, Santa Fe and Santa Cruz) and for finches (San Cristobal and Isabela vs. Santa Cruz and Floreana), and overall highly significantly distributed toward islands that were inhabited by humans (San Cristobal, Isabela, Floreana) vs. uninhabited at the time of collection (Santa Cruz, Santa Fe, Espanola), with only one positive individual on an uninhabited island. Eleven of the positive specimens sequenced successfully were identical at four diagnostic sites to the two canarypox variants previously described in contemporary Galapagos passerines. We conclude that this virus was introduced late in 1890's and was dispersed among islands by a variety of mechanisms, including regular human movements among colonized islands. At present, this disease represents an ongoing threat to the birds on the Galapagos Islands.

  11. Allometric and temporal scaling of movement characteristics in Galapagos tortoises.

    PubMed

    Bastille-Rousseau, Guillaume; Yackulic, Charles B; Frair, Jacqueline L; Cabrera, Freddy; Blake, Stephen

    2016-09-01

    Understanding how individual movement scales with body size is of fundamental importance in predicting ecological relationships for diverse species. One-dimensional movement metrics scale consistently with body size yet vary over different temporal scales. Knowing how temporal scale influences the relationship between animal body size and movement would better inform hypotheses about the efficiency of foraging behaviour, the ontogeny of energy budgets, and numerous life-history trade-offs. We investigated how the temporal scaling of allometric patterns in movement varies over the course of a year, specifically during periods of motivated (directional and fast movement) and unmotivated (stationary and tortuous movement) behaviour. We focused on a recently diverged group of species that displays wide variation in movement behaviour - giant Galapagos tortoises (Chelonoidis spp.) - to test how movement metrics estimated on a monthly basis scaled with body size. We used state-space modelling to estimate seven different movement metrics of Galapagos tortoises. We used log-log regression of the power law to evaluate allometric scaling for these movement metrics and contrasted relationships by species and sex. Allometric scaling of movement was more apparent during motivated periods of movement. During this period, allometry was revealed at multiple temporal intervals (hourly, daily and monthly), with values observed at daily and monthly intervals corresponding most closely to the expected one-fourth scaling coefficient, albeit with wide credible intervals. We further detected differences in the magnitude of scaling among taxa uncoupled from observed differences in the temporal structuring of their movement rates. Our results indicate that the definition of temporal scales is fundamental to the detection of allometry of movement and should be given more attention in movement studies. Our approach not only provides new conceptual insights into temporal attributes in one

  12. Allometric and temporal scaling of movement characteristics in Galapagos tortoises

    USGS Publications Warehouse

    Bastille-Rousseau, Guillaume; Yackulic, Charles B.; Frair, Jacqueline L.; Cabrera, Freddy; Blake, Stephen

    2016-01-01

    Understanding how individual movement scales with body size is of fundamental importance in predicting ecological relationships for diverse species. One-dimensional movement metrics scale consistently with body size yet vary over different temporal scales. Knowing how temporal scale influences the relationship between animal body size and movement would better inform hypotheses about the efficiency of foraging behaviour, the ontogeny of energy budgets, and numerous life-history trade-offs.We investigated how the temporal scaling of allometric patterns in movement varies over the course of a year, specifically during periods of motivated (directional and fast movement) and unmotivated (stationary and tortuous movement) behaviour. We focused on a recently diverged group of species that displays wide variation in movement behaviour – giant Galapagos tortoises (Chelonoidis spp.) – to test how movement metrics estimated on a monthly basis scaled with body size.We used state-space modelling to estimate seven different movement metrics of Galapagos tortoises. We used log-log regression of the power law to evaluate allometric scaling for these movement metrics and contrasted relationships by species and sex.Allometric scaling of movement was more apparent during motivated periods of movement. During this period, allometry was revealed at multiple temporal intervals (hourly, daily and monthly), with values observed at daily and monthly intervals corresponding most closely to the expected one-fourth scaling coefficient, albeit with wide credible intervals. We further detected differences in the magnitude of scaling among taxa uncoupled from observed differences in the temporal structuring of their movement rates.Our results indicate that the definition of temporal scales is fundamental to the detection of allometry of movement and should be given more attention in movement studies. Our approach not only provides new conceptual insights into temporal attributes in one

  13. Prevalence of Diabetes on Santa Cruz Island in Galapagos Archipelago

    PubMed Central

    Chowdhury, Tahseen

    2015-01-01

    This was an observational study offering a screening program for diabetes in a health clinic in Puerto Ayora town on Santa Cruz Island to determine the prevalence of this disorder and identify those at risk. A 1-month screening program was undertaken. Of 141 patients screened, 85% of men and 83% of women were overweight or obese; 16 (11%) had suspected undiagnosed diabetes and 22 (16%) were at high risk of developing diabetes. This is the first reported study of glucose intolerance prevalence in Galapagos. Urgent education and prevention programs are required to address this public health problem. PMID:26086607

  14. Evidence for melt channelization in Galapagos plume-ridge interaction

    NASA Astrophysics Data System (ADS)

    Mittal, T.; Richards, M. A.

    2015-12-01

    Many present-day hot spots are located within ~ 1000 km of a mid-ocean ridge, either currently or in the geologic past, leading to frequent interaction between these two magmatic regimes. The consequent plume-ridge interactions provide a unique opportunity to test models for asthenosphere-lithosphere dynamics, with the plume acting as a tracer fluid in the problem, and excess magmatism reflecting otherwise unsampled sub-surface phenomena. Galapagos is an off-ridge hotspot with the mantle plume located ~150-250 km south of the plate boundary. Plume-ridge interaction in Galapagos is expressed by the formation of volcanic lineaments of islands and seamounts - e.g., the Wolf-Darwin lineament (WDL) - providing a direct probe of the plume-ridge interaction process, especially in regards to geochemical data. Although several models have been proposed to explain plume-ridge interaction in Galapagos, none adequately explain the observed characteristics, especially the WDL. In particular, predicted lithospheric fault orientations and melt density considerations appear at odds with observations, suggesting that lithospheric extension is not the primary process for formation of these islands. Other off-ridge hotspots interacting with nearby spreading ridges, such as Reunion and Louisville, also exhibit volcanic lineaments linking the plume and the ridge. Thus these lineament-type features are a common outcome of plume-ridge interaction that are indicative of the underlying physics. We propose that the lineaments are surface expressions of narrow sub-lithospheric melt channels focused towards the spreading ridge. These channels should form naturally due to the reactive infiltration instability in a two-phase flow of magma and solid mantle as demonstrated in two-phase flow simulations (e.g., Katz & Weatherley 2012). For Galapagos, we show that melt channels can persist thermodynamically over sufficient length-scales to link the plume and nearby ridge segments. We also show that

  15. Same size--same niche? Foraging niche separation between sympatric juvenile Galapagos sea lions and adult Galapagos fur seals.

    PubMed

    Jeglinski, Jana W E; Goetz, Kimberley T; Werner, Christiane; Costa, Daniel P; Trillmich, Fritz

    2013-05-01

    1. In vertebrates, patterns of resource utilization change throughout development according to age- and or size-specific abilities and requirements. Thus, interspecific competition affects different age classes differently. 2. Adults of sympatric species often show distinct foraging niche segregation, but juvenile resource use might overlap with adult competitors of similar body size. Resultant negative effects on juveniles can have important consequences for population dynamics, yet such interactions have received little attention in studies of mammalian communities. 3. Using GPS tracking devices, time-depth recorders and stable isotope data, we compared diving depth, activity time, trophic position and foraging habitat characteristics to investigate foraging niche overlap between similar-sized sympatric juvenile Galapagos sea lions (Zalophus wollebaeki) and adult Galapagos fur seals (Arctocephalus galapagoensis) and compared each group with much larger-bodied adult Galapagos sea lions. 4. We found little indication for direct competition but a complex pattern of foraging niche segregation: juvenile sea lions and adult fur seals dived to shallow depths at night, but foraged in different habitats with limited spatial overlap. Conversely, juvenile and adult sea lions employed different foraging patterns, but their foraging areas overlapped almost completely. 5. Consistency of foraging habitat characteristics between juvenile and adult sea lions suggests that avoidance of competition may be important in shaping foraging habitat utilization. Resultant specialization on a limited habitat could contribute to low sea lion numbers that contrast with high fur seal abundance. Our data suggest that exploitation by multiple predators within spatially restricted foraging ranges of juveniles might negatively impact juvenile foraging success and ultimately influence population dynamics.

  16. DDT in endangered Galapagos sea lions (Zalophus wollebaeki).

    PubMed

    Alava, Juan Jose; Ross, Peter S; Ikonomou, Michael G; Cruz, Marilyn; Jimenez-Uzcátegui, Gustavo; Dubetz, Cory; Salazar, Sandie; Costa, Daniel P; Villegas-Amtmann, Stella; Howorth, Peter; Gobas, Frank A P C

    2011-04-01

    We characterize for the first time the presence of DDT and its metabolites in tropical Galapagos sea lions (Zalophus wolleabeki). ∑DDT concentrations in Galapagos sea lion pups sampled in 2005 and 2008 ranged from 16 to 3070 μg/kg lipid. Concentrations of ∑DDT in pups in 2008 averaged 525 μg/kg lipid and were 1.9 times higher than that (281 μg/kg lipid) detected in pups in 2005. These concentrations are lower than those reported in many pinnipeds elsewhere, comparable to those in Hawaiian monk seals, and higher than those in southern elephant seals. The health risk characterization showed that 1% of the male pups exceeded the p,p'-DDE toxic effect concentration associated with anti-androgenic effects reported in rats. The findings provide preliminary guidance on the relationship between DDT use and ecological impacts, serving as a reference point against which possible future impact of tropical DDT use can be assessed.

  17. DDT in endangered Galapagos sea lions (Zalophus wollebaeki).

    PubMed

    Alava, Juan Jose; Ross, Peter S; Ikonomou, Michael G; Cruz, Marilyn; Jimenez-Uzcátegui, Gustavo; Dubetz, Cory; Salazar, Sandie; Costa, Daniel P; Villegas-Amtmann, Stella; Howorth, Peter; Gobas, Frank A P C

    2011-04-01

    We characterize for the first time the presence of DDT and its metabolites in tropical Galapagos sea lions (Zalophus wolleabeki). ∑DDT concentrations in Galapagos sea lion pups sampled in 2005 and 2008 ranged from 16 to 3070 μg/kg lipid. Concentrations of ∑DDT in pups in 2008 averaged 525 μg/kg lipid and were 1.9 times higher than that (281 μg/kg lipid) detected in pups in 2005. These concentrations are lower than those reported in many pinnipeds elsewhere, comparable to those in Hawaiian monk seals, and higher than those in southern elephant seals. The health risk characterization showed that 1% of the male pups exceeded the p,p'-DDE toxic effect concentration associated with anti-androgenic effects reported in rats. The findings provide preliminary guidance on the relationship between DDT use and ecological impacts, serving as a reference point against which possible future impact of tropical DDT use can be assessed. PMID:21353257

  18. Imaging Enhancement on Deep Seismic Reflection with Petrel and Ocean Working Environment

    NASA Astrophysics Data System (ADS)

    Yu, P.; Huang, D.; Feng, X.; Li, L.; Liu, W.; Wang, Y.; Zhao, Q.

    2011-12-01

    SinoProbe has been initiated to enhance understanding of earth deep structure, resources and geological disasters forecasting throughout Chinese continent. Besides traditional deep exploration methods, various state-of-the-art technologies have been carried out in order to acquire data and jointly utilize all possible information reflecting deep crust and mantle structures and evolution.Petrel, a powerful software application developed by Schlumberger, has been successfully applied to the O&G industry. It is now a complete seismic-to-simulation application for 3D and 2D seismic interpretation. However, it has a great potential to allow the user to extend utilization with multiple types of data sets to deal with much deeper geophysical information. Petrel all-in-one concept, that functionally comprises of massive data integration, multiple domains experts participation and 3D geological object-oriented etc., will come benefit to the deep earth study. Currently, there is no special tool designed for this purpose so that Petrel is required to extend its potential to cope with not only O&G area but also a larger area with unique requests of deeper objects.Ocean, a software framework for Petrel, provides an open development environment offering seamless integration of developer intellectual contribution to the Petrel mainstream workflow. It is able to accelerate the development and deployment of user's Petrel-like workflows to resolve complex problems. It can be implemented by means of plug-ins utilities although there is additional challenge to write a robust code with Ocean framework. Deep seismic reflection profiling is a well recognized technique to reveal the fine structure of lithosphere. Moreover, it can perform a significant role for prospective evaluation of O&G and mineral resources, and geological disasters. Its near-vertical deep seismic reflection method can enhance broad band seismic observations for imaging of the deep crust and continental geodynamics

  19. Metal and selenium concentrations in blood and feathers of petrels of the genus Procellaria.

    PubMed

    Carvalho, Paloma Calábria; Bugoni, Leandro; McGill, Rona A R; Bianchini, Adalto

    2013-07-01

    Concentrations of copper (Cu), zinc (Zn), cadmium (Cd), lead (Pb), mercury (Hg), and selenium (Se) were determined in blood and feathers of spectacled (Procellaria conspicillata) and white-chinned (Procellaria aequinoctialis) petrels, species that are phylogenetically related, but with distinct ecological niches. In winter, they feed on similar foods, indicated by an overlapping range of whole-blood stable isotopes values (δ(15) N; δ(13) C). No relation was found between blood metal concentration and stable isotope values. In spectacled petrels, metal concentrations appeared lower in blood (Cu = 0.79-20.77 µg/g; Zn = 10.95-28.02 µg/g; Cd = 1.73-10.11 µg/g; Pb = 5.02-26.03 µg/g; Hg = 0.84-9.86 µg/g) than in feathers (Cu = 1.05-21.57 µg/g; Zn = 45.30-81.49 µg/g; Cd = 3.76-10.44 µg/g; Pb = 16.53-59.00 µg/g; Hg = 4.24-24.03 µg/g). In white-chinned petrels, metal concentrations also appeared lower in blood (Cu = 0.62-10.4 µg/g; Zn = 10.73-24.69 µg/g; Cd = 2.00-6.31 µg/g; Pb = 5.72-24.03 µg/g) than in feathers (Cu = 2.68-23.92 µg/g; Zn = 48.96-93.54 µg/g; Cd = 5.72-24.03 µg/g; Pb = 18.62-55.51 µg/g), except for Hg (blood = 0.20-15.82 µg/g; feathers = 0.19-8.91 µg/g). Selenium (0.24-14.18 µg/g) and Hg (0.22-1.44 µg/g) concentrations showed a positive correlation in growing feathers of spectacled petrels. Blood and feather Hg levels were higher in spectacled petrels while feathers Cu and Zn concentrations were greater in white-chinned petrels. Juvenile white-chinned petrels exhibited greater blood Hg concentrations than adults. In the south Atlantic Ocean, discards from commercial fishing operations consumed by spectacled petrels year-round and by white-chinned petrels during the wintering period have elevated Hg concentrations. Because Hg toxicity is associated with behavioral and reproductive changes in birds, it could

  20. Lithospheric Evolution of Magmas from the Northern Galapagos Province

    NASA Astrophysics Data System (ADS)

    Miller, M.; Geist, D.; Harpp, K. S.; Mittelstaedt, E. L.

    2010-12-01

    Volcanoes of the Northern Galapagos Providence (NGP) are crucial to understanding the interaction between the Galapagos Plume and the Galapagos Spreading Center (GSC). The NGP consists of five islands and nine volcanic lineaments, all located south of the GSC. Major and trace element compositions of seamounts within the NGP provide insight into the lithospheric evolution of magma within the province. The FLAMINGO cruise (June, 2010) dredged forty-seven localities in the NGP. Major element compositions were determined by XRF and microprobe analysis of submarine rocks and glasses. Crystallization as a function of pressure and temperature is modeled with MELTS and projections into ternary phase diagrams. The Wolf-Darwin Lineament (WDL) is divided into three groups for evaluation of the lavas’ petrology: Northern Wolf-Darwin lineament (that closest to the GSC including Darwin Island), Middle Wolf-Darwin lineament (MWDL, which includes Wolf Island), and Southern Wolf-Darwin lineament (that closest to the Galapagos Platform). Lavas from two other lineaments to the east of the WDL and around Pinta Island are assessed as well. Two parental compositions are modeled, one enriched and one depleted (K2O/TiO2 >0.23 as enriched and K2O/TiO2 =0.04 as depleted). CaO/Al2O3 and Al2O3 variations with Mg# vary considerably as a function of pressure. Magmas from most of the subregions of the NGP evolved by crystallization of olivine and plagioclase, with little CPX crystallization. This indicates that crystallization beneath these volcanoes is limited to pressures < 1 kb. In contrast, some MWDL magmas evolve by extensive crystallization of clinopyroxene-bearing assemblages, and our best pressure estimate is 3 kb. CPX crystallization is most likely due to polybaric crystal fractionation at the MWDL. Some of the NGP glasses are very rich in Al2O3, especially those of the MWDL, which peak at Al2O3 17.0 wt.% at Mg# of 59. The maximum Al2O3 of the other WDL subprovinces is 16.7 wt.%, at

  1. Galapagos Penguins in a Warming World: An Exemplar of Biological Loopholes in the Anthropocene

    NASA Astrophysics Data System (ADS)

    Karnauskas, K. B.; Jenouvrier, S.; Brown, C.; Murtugudde, R. G.

    2015-12-01

    The Galapagos is a flourishing yet fragile ecosystem whose health is particularly sensitive to regional and global climate variations. The distribution of several species, including the Galapagos Penguin, is intimately tied to upwelling of cold, nutrient-rich water along the western shores of the archipelago. Here we show, using reliable, high-resolution sea surface temperature observations, that the Galapagos cold pool has been intensifying and expanding northward since 1982. The linear cooling trend of 0.8°C per 33 years is likely the result of long-term changes in equatorial ocean circulation previously identified. Moreover, the northward expansion of the cold pool is dynamically consistent with a slackening of the cross-equatorial component of the regional trade winds—leading to an equatorward shift of the mean position of the Equatorial Undercurrent. The implied change in strength and distribution of upwelling has important implications for ongoing and future conservation measures in the Galapagos.

  2. Effects of human disturbance on cave-nesting seabirds: the case of the storm petrel.

    PubMed

    Soldatini, Cecilia; Albores-Barajas, Yuri V; Tagliavia, Marcello; Massa, Bruno; Fusani, Leonida; Canoine, Virginie

    2015-01-01

    Human disturbance is an important stress factor with potentially strong impact on breeding activity in animals. The consequences can be extinction of the breeding population, because disturbed animals might desert their breeding area and find no suitable substitute area. In this study, we investigated the effects of anthropogenic disturbance on a breeding population of Mediterranean storm petrels. Seabirds are increasingly used as bio-indicators for sea environmental parameters, because they are very sensitive to changing conditions. Burrowing or cave-nesting species may be particularly susceptible to human disturbance because their direct contact with humans is usually minimal or absent. First, we compared two different populations (exposed or not exposed to human disturbance) for their individual stress response to a standardized stressor (handling and keeping in a cloth bag). Second, we compared the two sub-colonies for their population-level stress response. Third, we tested experimentally whether sub-colonies of storm petrels exposed to tourism have physiological adaptations to anthropogenic disturbances. Our results indicate that storm petrels may be habituated to moderate disturbance associated with boat traffic close to the colony.

  3. Effects of human disturbance on cave-nesting seabirds: the case of the storm petrel

    PubMed Central

    Soldatini, Cecilia; Albores-Barajas, Yuri V.; Tagliavia, Marcello; Massa, Bruno; Fusani, Leonida; Canoine, Virginie

    2015-01-01

    Human disturbance is an important stress factor with potentially strong impact on breeding activity in animals. The consequences can be extinction of the breeding population, because disturbed animals might desert their breeding area and find no suitable substitute area. In this study, we investigated the effects of anthropogenic disturbance on a breeding population of Mediterranean storm petrels. Seabirds are increasingly used as bio-indicators for sea environmental parameters, because they are very sensitive to changing conditions. Burrowing or cave-nesting species may be particularly susceptible to human disturbance because their direct contact with humans is usually minimal or absent. First, we compared two different populations (exposed or not exposed to human disturbance) for their individual stress response to a standardized stressor (handling and keeping in a cloth bag). Second, we compared the two sub-colonies for their population-level stress response. Third, we tested experimentally whether sub-colonies of storm petrels exposed to tourism have physiological adaptations to anthropogenic disturbances. Our results indicate that storm petrels may be habituated to moderate disturbance associated with boat traffic close to the colony. PMID:27293726

  4. Southern giant Petrel Macronectes giganteus nest attendance patterns under extreme weather conditions.

    PubMed

    Schulz, Uwe Horst; Krüger, Lucas; Petry, Maria Virginia

    2014-08-01

    Differences in nest attendance between genders in seabirds may be related to morphological differences. Southern giant petrel is a dimorphic species with gender-specific foraging behavior. The objective of this study was to investigate sex-related differences in nest attendance during the breeding period of southern giant petrels by presence/absence patterns of both sexes during incubation and compare use of the colony after nest failure. Fourteen birds were tagged with digitally coded radio-transmitters in a colony at Elephant Island, Antarctica, in the beginning of 2009/2010 breeding season. Females were present during 18 periods (min. 3 days, max. 9 days) and males only in five periods (min. 2 days, max. 13 days). The difference in mean number of radio signals per day between females (4330; s.e. 313.5) and males (2691; s.e. 248.6) was highly significant (t = 4.3; d.f. = 199; P < 0.001; Fig. 4 ). As consequence of the severe weather conditions that year, all tagged birds failed to reproduce. After abandonment of the nests, the presence of both genders decreased drastically, although the tagged individuals stayed in the area. Under severe weather conditions female Southern Giant Petrels continue breeding while males abandon the nest earlier. PMID:25088590

  5. Behavioral attraction of Leach's storm-petrels (Oceanodroma leucorhoa) to dimethyl sulfide.

    PubMed

    Nevitt, Gabrielle A; Haberman, Karen

    2003-05-01

    A recent model for olfactory foraging by procellariiform seabirds suggests that these birds use biogenic sulfur compounds to locate productive areas for foraging in the southern oceans. The present study refines a simple approach to test birds' responses to odors on land and extends our knowledge to a northern species, the Leach's storm-petrel (Oceanodroma leucorhoa). Rather than working at sea, we tested the behavioral response to dimethyl sulfide (DMS) at night in breeding colonies on Kent Island, New Brunswick, Canada. Birds were presented with either 5 ml DMS (100 micro mol l(-1) concentration) or control (water) solutions from a platform 1.5 m in height positioned in a flyway 10 m from a breeding colony. We also tested birds' responses to cod liver oil, a well-established olfactory attractant of procellariiforms foraging at sea. Leach's storm-petrels approached DMS presentations nearly twice as frequently as they approached controls. We next compared the distribution of approaches against a Poisson process to test for evidence of social cueing. We found that approaches to DMS were significantly clustered. By contrast, the distribution of approaches did not depart significantly from a Poisson distribution for either cod liver oil or control presentations. Taken together, these results suggest that Leach's storm-petrels can smell DMS and potentially use it as a foraging cue. The results are consistent with the hypothesis that the detection of biogenic sulfur compounds in combination with other cues assists birds in locating foraging hotspots. PMID:12654888

  6. Ecological segregation in space, time and trophic niche of sympatric planktivorous petrels.

    PubMed

    Navarro, Joan; Votier, Stephen C; Aguzzi, Jacopo; Chiesa, Juan J; Forero, Manuela G; Phillips, Richard A

    2013-01-01

    The principle of competitive exclusion postulates that ecologically-similar species are expected to partition their use of resources, leading to niche divergence. The most likely mechanisms allowing such coexistence are considered to be segregation in a horizontal, vertical or temporal dimension, or, where these overlap, a difference in trophic niche. Here, by combining information obtained from tracking devices (geolocator-immersion and time depth recorders), stable isotope analyses of blood, and conventional morphometry, we provide a detailed investigation of the ecological mechanisms that explain the coexistence of four species of abundant, zooplanktivorous seabirds in Southern Ocean ecosystems (blue petrel Halobaena caerulea, Antarctic prion Pachyptila desolata, common diving petrel Pelecanoides urinatrix and South Georgian diving petrel P. georgicus). The results revealed a combination of horizontal, vertical and temporal foraging segregation during the breeding season. The stable isotope and morphological analyses reinforced this conclusion, indicating that each species occupied a distinct trophic space, and that this appears to reflect adaptations in terms of flight performance. In conclusion, the present study indicated that although there was a degree of overlap in some measures of foraging behaviour, overall the four taxa operated in very different ecological space despite breeding in close proximity. We therefore provide important insight into the mechanisms allowing these very large populations of ecologically-similar predators to coexist. PMID:23646155

  7. Effects of human disturbance on cave-nesting seabirds: the case of the storm petrel.

    PubMed

    Soldatini, Cecilia; Albores-Barajas, Yuri V; Tagliavia, Marcello; Massa, Bruno; Fusani, Leonida; Canoine, Virginie

    2015-01-01

    Human disturbance is an important stress factor with potentially strong impact on breeding activity in animals. The consequences can be extinction of the breeding population, because disturbed animals might desert their breeding area and find no suitable substitute area. In this study, we investigated the effects of anthropogenic disturbance on a breeding population of Mediterranean storm petrels. Seabirds are increasingly used as bio-indicators for sea environmental parameters, because they are very sensitive to changing conditions. Burrowing or cave-nesting species may be particularly susceptible to human disturbance because their direct contact with humans is usually minimal or absent. First, we compared two different populations (exposed or not exposed to human disturbance) for their individual stress response to a standardized stressor (handling and keeping in a cloth bag). Second, we compared the two sub-colonies for their population-level stress response. Third, we tested experimentally whether sub-colonies of storm petrels exposed to tourism have physiological adaptations to anthropogenic disturbances. Our results indicate that storm petrels may be habituated to moderate disturbance associated with boat traffic close to the colony. PMID:27293726

  8. Dynamics of the Galapagos hotspot from helium isotope geochemistry

    SciTech Connect

    Kurz, M.D.; Geist, D.

    1999-12-01

    The authors have measured the isotopes of He, Sr, Nd and Pb in a number of lava flows from the Galapagos Archipelago; the main goal is to use magmatic helium as a tracer of plume influence in the western volcanoes. Because the Galapagos lava flows are so well preserved, it is also possible to measure surface exposure ages using in situ cosmic-ray-produced {sup 3}He. The exposure ages range from {lt}0.1 to 580 Ka, are consistent with other chronological constrains, and provide the first direct dating of these lava flows. The new age data demonstrate the utility of the technique in this important age range and show that the western Galapagos volcanoes have been erupting distance compositions simultaneously for the last {approximately}10 Ka. The magmatic {sup 3}He/{sup 4}He ratios range from 6.0 to 27 times atmospheric (R{sub a}), with the highest values found on the islands of Isabella (16.8 R{sub a} for Vulcan Sierra Negra) and Fernandina (23 to 27 R{sub a}). Values from Santa Cruz are close to typical mid-ocean ridge basalt values (MORB, of {approximately}9 R{sub 2}) and Pinta has a {sup 3}He/{sup 4}He ratio lower than MORB (6.9 R{sub a}). These data confirm that the plume is centered beneath Fernandina which is the most active volcano in the archipelago and is at the leading edge of plate motion. The data are consistent with previous isotopic studies, confirming extensive contributions from depleted asthenospheric or lithospheric mantle sources, especially to the central islands. The most striking aspect of the helium isotopic data is that the {sup 3}He/{sup 4}He ratios decrease systematically in all directions from Fernandina. This spatial variability is assumed to reflect the contribution of the purest plume component to Fernandina magmatism, and shows that helium is a sensitive indicator of plume influence. The highest {sup 3}He/{sup 4}He ratios are found in volcanoes with lowest Na{sub 2}O(8) and FeO(8), which may relate to source composition as well as degree

  9. Three dimensional perspective view of portion of western Galapagos Islands

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a three dimensional perspective view of Isla Isabela in the western Galapagos Islands. It was taken by the L-band radar in HH polarization from the Spaceborne Imaging Radar-C/X-Band Synthetic Aperature Radar on the 40th orbit of the Shuttle Endeavour. This view was constructed by overlaying a SIR-C radar image on a U.S. Geological Survey digital elevation map. The image is centered at about .5 degrees south latitude and 91 degrees West longitude and covers an area of 75 km by 60 km. This SIR-C/X-SAR image of Alcedo and Sierra Negra volcanoes shows the rougher lava flows as bright features, while ash deposits and smooth Pahoehoe lava flows dark. The Jet Propulsion Laboratory alternative photo number is P-43938.

  10. Latitudinal exposure to DDTs, HCB, PCBs, PBDEs and DP in giant petrels (Macronectes spp.) across the Southern Ocean.

    PubMed

    Roscales, Jose L; González-Solís, Jacob; Zango, Laura; Ryan, Peter G; Jiménez, Begoña

    2016-07-01

    Studies on Persistent Organic Pollutants (POPs) in Antarctic wildlife are scarce, and usually limited to a single locality. As a result, wildlife exposure to POPs across the Southern Ocean is poorly understood. In this study, we report the differential exposure of the major southern ocean scavengers, the giant petrels, to POPs across a wide latitudinal gradient. Selected POPs (PCBs, HCB, DDTs, PBDEs) and related compounds, such as Dechlorane Plus (DP), were analyzed in plasma of southern giant petrels (Macronectes giganteus) breeding on Livingston (62°S 61°W, Antarctica), Marion (46°S 37°E, sub-Antarctic), and Gough (40°S 10°W, cool temperate) islands. Northern giant petrels (Macronectes halli) from Marion Island were also studied. Stable isotope ratios of C and N (δ(13)C and δ(15)N) were used as dietary tracers of the marine habitat and trophic level, respectively. Breeding locality was a major factor explaining petrel exposure to POPs compared with species and sex. Significant relationships between δ(13)C values and POP burdens, at both inter- and intra-population levels, support latitudinal variations in feeding grounds as a key factor in explaining petrel pollutant burdens. Overall, pollutant levels in giant petrels decreased significantly with latitude, but the relative abundance (%) of the more volatile POPs increased towards Antarctica. DP was found at negligible levels compared with legacy POPs in Antarctic seabirds. Spatial POP patterns found in giant petrels match those predicted by global distribution models, and reinforce the hypothesis of atmospheric long-range transport as the main source of POPs in Antarctica. Our results confirm that wildlife movements out of the polar region markedly increase their exposure to POPs. Therefore, strategies for Antarctic wildlife conservation should consider spatial heterogeneity in exposure to marine pollution. Of particular relevance is the need to clarify the exposure of Antarctic predators to emerging

  11. Latitudinal exposure to DDTs, HCB, PCBs, PBDEs and DP in giant petrels (Macronectes spp.) across the Southern Ocean.

    PubMed

    Roscales, Jose L; González-Solís, Jacob; Zango, Laura; Ryan, Peter G; Jiménez, Begoña

    2016-07-01

    Studies on Persistent Organic Pollutants (POPs) in Antarctic wildlife are scarce, and usually limited to a single locality. As a result, wildlife exposure to POPs across the Southern Ocean is poorly understood. In this study, we report the differential exposure of the major southern ocean scavengers, the giant petrels, to POPs across a wide latitudinal gradient. Selected POPs (PCBs, HCB, DDTs, PBDEs) and related compounds, such as Dechlorane Plus (DP), were analyzed in plasma of southern giant petrels (Macronectes giganteus) breeding on Livingston (62°S 61°W, Antarctica), Marion (46°S 37°E, sub-Antarctic), and Gough (40°S 10°W, cool temperate) islands. Northern giant petrels (Macronectes halli) from Marion Island were also studied. Stable isotope ratios of C and N (δ(13)C and δ(15)N) were used as dietary tracers of the marine habitat and trophic level, respectively. Breeding locality was a major factor explaining petrel exposure to POPs compared with species and sex. Significant relationships between δ(13)C values and POP burdens, at both inter- and intra-population levels, support latitudinal variations in feeding grounds as a key factor in explaining petrel pollutant burdens. Overall, pollutant levels in giant petrels decreased significantly with latitude, but the relative abundance (%) of the more volatile POPs increased towards Antarctica. DP was found at negligible levels compared with legacy POPs in Antarctic seabirds. Spatial POP patterns found in giant petrels match those predicted by global distribution models, and reinforce the hypothesis of atmospheric long-range transport as the main source of POPs in Antarctica. Our results confirm that wildlife movements out of the polar region markedly increase their exposure to POPs. Therefore, strategies for Antarctic wildlife conservation should consider spatial heterogeneity in exposure to marine pollution. Of particular relevance is the need to clarify the exposure of Antarctic predators to emerging

  12. At-sea distribution of radio-marked Ashy Storm-Petrels Oceanodroma homochroa captured on the California Channel Islands

    USGS Publications Warehouse

    Adams, J.; Takekawa, J.Y.

    2008-01-01

    Small, rare and wide-ranging pelagic birds are difficult to locate and observe at sea; little is therefore known regarding individual movements and habitat affinities among many of the world's storm-petrels (Family Hydrobatidae). We re-located 57 of 70 radio-marked Ashy Storm-Petrels Oceanodroma homochroa captured at three colonies in the California Channel Islands: Scorpion Rocks (2004, 2005), Santa Barbara Island (2004) and Prince Island (2005). Between 23 July and 22 September 2004, and 5 July and 4 August 2005, we flew 29 telemetry surveys, covered more than 65 000 km2 (2004) and 43 000 km2 (2005) of open ocean from San Nicolas Island north to the Farallon Islands and obtained 215 locations from 57 storm-petrels at sea. In both years, radio-marked storm-petrels were aggregated over the continental slope from Point Conception to Point Buchon, within the western Santa Barbara Channel, and over the Santa Cruz Basin between Santa Cruz, San Nicolas and Santa Barbara islands. Individuals captured in the Channel Islands ranged more than 600 km and were located as far north as Gulf of the Farallones National Marine Sanctuary. This is the first study to use radiotelemetry to determine the at-sea distribution and movements for any storm-petrel species.

  13. Notes on parasites in penguins (Spheniscidae) and petrels (Procellariidae) in the Antarctic and Sub-antarctic.

    PubMed

    Jones, H I

    1988-01-01

    Blood smears were examined from 143 penguins of four species (Aptenodytes patagonicus, Eudyptes chrysolophus, E. schlegeli, and Pygoscelis gentoo) from Sub-antarctic Macquarie Island and Heard Island. No blood parasites were reported. The vectors of Hepatozoon albatrossi (reported from three species of albatross) are probably shared by penguins, and it is suggested that the latter are not susceptible to infection with this protozoan. Cestodes of the genus Tetrabothrius were present in large numbers in the intestines of 17 Antarctic petrels (Thalassoica antarctica), and evidence is presented indicating that euphausiid crustaceans may be intermediate hosts. PMID:3352088

  14. Caldera collapse unloading volcanoes: the textbook case of Fernandina, Galapagos

    NASA Astrophysics Data System (ADS)

    Corbi, F.; Rivalta, E.; Pinel, V.; Maccaferri, F.; Acocella, V.

    2014-12-01

    Calderas are topographical depressions resulting from the yielding of magma chambers roof after large eruptions or intrusive events. On the outer slope, most calderas display radial fissures and, in limited cases, also circumferential fissures. Despite many hypotheses, the conditions controlling the formation of radial and/or circumferential fissures, and thus the shallow magma transfer within the volcano slopes, are still poorly understood. Here we demonstrate with numerical and analog models that the mass redistribution associated with caldera formation promotes shallow sill-shaped magma chambers and controls the orientation of eruptive fissures. We find that depending on the initial injection depth, dikes will bend or twist about an axis parallel to propagation resulting in circumferential and radial eruptive fissures, respectively. This mechanism is governed by the competition between gravitational unloading pressure and dike overpressure. We apply our results to Fernandina (Galapagos, Ecuador), the best case of caldera with radial and circumferential fissures, showing that the predicted stress field caused by the caldera unloading is consistent with the pattern of eruptive fissures and the dynamics of magma propagation.

  15. Attenuation Tomography of Sierra Negra Volcano of the Galapagos Archipelago

    NASA Astrophysics Data System (ADS)

    Rodd, R.; Lees, J. M.

    2014-12-01

    Following relocation of events with the double-difference location algorithm (HypoDD), we apply tomographic methods to extract 3D attenuation models illuminating the plumbing system of the Sierra Negra Caldera of the Galapagos Archipelago. The dataset consists of 1737 events recorded from July 2009 to June 2011 on the 17-station SIGNET broadband seismic array. We use t* spectral decay methods for both P- and S- phases with the clustered locations to highlight locations where significant variations in Q suggest the presence of magma melt. While the presence of a magma sill, at least 2 km depth, is indicated by InSAR and GPS studies, the delineated magma body has not been explored in detail. The lower bound of the proposed magma accumulation is still under question and thus forms the primary target of this research. Melt replenishment and degassing of the magma sill is believed to cause inflation and/or deflation of the caldera floor. Imaging the extent of the magma sill will provide insight into the feeder system and deformation process of the Sierra Negra caldera. Detailed relocation, Qp and Qs inversion, as well as estimates of the scattering attenuation using coda-normalization technique will be presented. The close relationship between seismic attenuation and the thermal state of the magmatic system suggests we can distinguish melt and/or fluid regions within the Sierra Negra plumbing system.

  16. Stable isotopes of carbon and nitrogen in the study of organochlorine contaminants in albatrosses and petrels.

    PubMed

    Colabuono, Fernanda I; Barquete, Viviane; Taniguchi, Satie; Ryan, Peter G; Montone, Rosalinda C

    2014-06-15

    Carbon and nitrogen stable isotopes in albatrosses and petrels collected off southern Brazil were compared with concentrations of organochlorine contaminants (OCs). δ(13)C and δ(15)N values, as well as OCs concentrations, exhibited a high degree of variability among individuals and overlap among species. δ(13)C values reflected latitudinal differences among species, with lower values found in Wandering and Tristan Albatrosses and higher values found in Black-browed and Atlantic Yellow-nosed Albatrosses and White-chinned Petrels. Some relationships were found between OCs and stable isotopes, but in general a partial 'uncoupling' was observed between OCs concentrations and stable isotopes ratios (especially for δ(15)N). δ(13)C and δ(15)N values in Procellariiformes tissues during the non-breeding season appear to be a better indicator of foraging habitats than of trophic relationships, which may partially explain the high degree of variability between concentrations of OCs and stable isotopes ratios in birds with a diversified diet and wide foraging range.

  17. Monitoring of a Southern Giant Petrel Macronectes giganteus population on the Frazier Islands, Wilkes Land, Antarctica

    USGS Publications Warehouse

    Creuwels, J.C.S.; Stark, J.S.; Woehler, Eric J.; Van Franeker, J. A.; Ribic, C.A.

    2005-01-01

    Since 1956, Southern Giant Petrels on the Frazier Islands, East Antarctica, have been counted with different census techniques, sometimes varying within seasons and among islands, which hindered analysis of the data. Protective measures for the islands from 1986 onwards have increased the need for reliable long-term census data, but reduced the ways to collect these data. Published and unpublished data were re-examined, and population trends were reconstructed based on two relatively standardised techniques: the number of active chicks (AC) and the number of apparently occupied nests (AON) around hatching. AC-values from Nelly Island from 1959 to 1998 indicate substantial periodic fluctuations, but no consistent long-term change. Since the late 1970s, AC-values on the other two islands and AON-values suggest that the breeding population may have grown by 35%. This recent growth, however, is within the extent of periodic fluctuations observed in Southern Giant Petrel population that is stable over the long term. ?? Springer-Verlag 2004.

  18. Is basal metabolic rate influenced by age in a long-lived seabird, the snow petrel?

    PubMed

    Moe, Børge; Angelier, Frédéric; Bech, Claus; Chastel, Olivier

    2007-10-01

    Ageing is associated with a decline in basal metabolic rate (BMR) in many species, including humans. The evolutionary and physiological causes underlying the relationship between age and BMR are poorly understood. Studies of procellariiform seabirds may provide valuable insight because they have a longer maximum lifespan than expected from their body size and rates of energy metabolism. Such studies are rare, however, because there are few populations with a high proportion of individuals of known age. We performed a cross-sectional study of energy metabolism in relation to age in a long-lived seabird, the snow petrel Pagodroma nivea. In an Antarctic population that has been subject to a long-term research program, including annual banding of chicks since 1963, we measured BMR of individuals aged between 8 and 39 years. We show that the BMR of the snow petrel does not decrease with increasing age. BMR seems to be sustained at a fixed level throughout the investigated age-span. We review this result in light of the disposable soma theory of ageing, and we discuss whether species-specific relationships between age and basal metabolic rate can be related to differences in maximum lifespan. PMID:17872994

  19. Bile is essential for lipid assimilation in Leach's storm petrel, Oceanodroma leucorhoa.

    PubMed

    Place, A R

    1992-08-01

    A tritium-labeled glycerol triether was tested as a non-absorbable lipid marker for studies of neutral lipid absorption in normal and cholestryamine-induced steatorrhic chicks of Leach's storm petrel (Oceanodroma leucorhoa). Absorption of triacylglycerol and wax ester (96 +/- 4.2 and 94 +/- 2.1%, respectively) in normal chicks was indistinguishable. Absorption of neutral lipids decreased with increasing quantities of resin, and with the highest dosage (14% wt/wt) less than 30% of dietary lipids were assimilated. The concentration of bile salts (greater than 500 mM) in the gallbladder of Leach's storm petrel is among the highest recorded. The bile salts are predominantly taurine conjugates of chenodeoxycholate and cholate. Biliary cholesterol levels are within the range observed in humans although biliary phospholipid levels are lower and triglyceride levels are higher. Extensive retrograde movement of duodenal contents and biliary secretions to the gizzard and proventriculus were found. Although similarities in fat and bile salt assimilation exist between seabirds and mammals, there do exist differences that make non-polar lipid assimilation (i.e., wax esters) more efficient in seabirds. PMID:1510178

  20. Cutaneous and diphtheritic avian poxvirus infection in a nestling Southern Giant Petrel (Macronectes giganteus) from Antarctica

    USGS Publications Warehouse

    Shearn-Bochsler, Valerie; Green, David Earl; Converse, K.A.; Docherty, D.E.; Thiel, T.; Geisz, H.N.; Fraser, William R.; Patterson-Fraser, Donna L.

    2008-01-01

    The Southern giant petrel (Macronectes giganteus) is declining over much of its range and currently is listed as vulnerable to extinction by the International Union for the Conservation of Nature (IUCN). Island-specific breeding colonies near Palmer Station, Antarctica, have been monitored for over 30 years, and because this population continues to increase, it is critically important to conservation. In austral summer 2004, six diseased giant petrel chicks were observed in four of these colonies. Diseased chicks were 6a??9 weeks old and had multiple proliferative nodules on their bills and skin. One severely affected chick was found dead on the nest and was salvaged for necropsy. Histopathological examination of nodules from the dead chick revealed epithelial cell hyperplasia and hypertrophy with numerous eosinophilic intracytoplasmic inclusions (B??llinger bodies). A poxvirus was isolated from multiple nodules. Poxviral infection has not been reported in this species, and the reason for its emergence and its potential impact on the population are not yet known.

  1. Examining the development of individual recognition in a burrow-nesting procellariiform, the Leach's storm-petrel.

    PubMed

    O'Dwyer, Terence W; Ackerman, A L; Nevitt, Gabrielle A

    2008-02-01

    Burrow-nesting petrels use their well-developed sense of smell for foraging, homing to their nest, and mate recognition. The chicks of burrow-nesting petrels can apparently learn odours associated with prey while still in the nest, but the development of individual-specific odour recognition is less well understood. We used a simple two-choice test to determine whether 4- to 6-week-old chicks of a small, burrow-nesting species, the Leach's storm-petrel (Oceanodroma leucorhoa), prefer the scent of their own nest material to (1) the scent of similar organic material collected from the colony or (2) the scent of a conspecific's nest material. Results suggest that chicks clearly preferred the scent of their own nest material to that of similar organic material collected from the colony (96%; N=24; binomial test, P<0.001). Results further suggested that birds preferred the scent of their own nest material to that of a conspecific, though the preference was statistically less robust (67%; N=39; binomial test, P=0.05). Because Leach's storm-petrel chicks do not normally leave their burrow prior to fledging, an ability to recognise individual or nest-specific odours is not likely to be used for homing but instead may be linked to the development of individual recognition in different contexts. PMID:18203988

  2. Cool, cold or colder? Spatial segregation of prions and blue petrels is explained by differences in preferred sea surface temperatures.

    PubMed

    Quillfeldt, Petra; Cherel, Yves; Delord, Karine; Weimerkirch, Henri

    2015-04-01

    The Southern Ocean provides one of the largest environmental gradients on Earth that lacks geographical barriers, and small but highly mobile petrels living there may offer fine models of evolution of diversity along environmental gradients. Using geolocation devices, we investigated the winter distribution of closely related petrel species breeding sympatrically in the southern Indian Ocean, and applied ecological niche models to compare environmental conditions in the habitat used. We show that thin-billed prions (Pachyptila belcheri), Antarctic prions (Pachyptila desolata) and blue petrels (Halobaena caerulea) from the Kerguelen archipelago in the southern Indian Ocean segregate latitudinally, sea surface temperature being the most important variable separating the distribution of the species. Antarctic prions spent the winter north of the Polar Front in temperate waters, whereas blue petrels were found south of the Polar Front in Antarctic waters. Thin-billed prions preferred intermediate latitudes and temperatures. Stable isotope values of feathers reflected this near complete niche separation across an ecological gradient that spans large scales, and suggest evolutionary isolation by environment. In pelagic seabirds that exploit large areas of ocean, spatial niche partitioning may not only facilitate coexistence among ecologically similar species, but may also have driven their evolution in the absence of geographical barriers. PMID:25878044

  3. Distribution and at-sea activity of a nocturnal seabird, the Bulwer's petrel Bulweria bulwerii, during the incubation period

    NASA Astrophysics Data System (ADS)

    Dias, Maria P.; Romero, Joana; Granadeiro, José Pedro; Catry, Teresa; Pollet, Ingrid L.; Catry, Paulo

    2016-07-01

    Bulwer's petrels are nocturnal seabirds that mostly prey on mesopelagic fauna. As aerial foragers and shallow divers, their feeding opportunities are limited by near-surface availability of their prey, which is highly variable both temporally (reflecting diurnal and lunar cycles) and spatially. Here we studied how Bulwer's petrels cope with these constraints by analysing their at-sea distribution and activity during the incubation period. We tracked the movements of 20 birds from Selvagem Grande (NE Atlantic) during a complete lunar cycle, and recorded 30 foraging trips that lasted 11 days on average. Birds were both distributed around the colony and in waters close to the Azorean archipelago (mid-Atlantic) located 1700 km away, and were significantly more active at night (especially just after sunset and before sunrise), when mesopelagic fauna is also closer to the sea surface due to their diel vertical migrations. Bulwer's petrels spent significantly more time flying during moonlight, although the effect of the moon was relatively weak (ca. 10-15% difference between moonlit and dark periods of the night), and not obvious when birds were foraging in mid-Atlantic waters, which were also targeted more often during full-moon. These results reveal key adaptations of the Bulwer's petrel to the highly dynamic ecology of its mesopelagic prey.

  4. 75 FR 310 - Endangered and Threatened Wildlife and Plants; Withdrawal of Proposed Rule to List Cook's Petrel

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-05

    ...). The population of the Cook's petrel on Little Barrier Island was thought to be about 50,000 pairs (BLI... Great Barrier Island population was considered to be in danger of extirpation because only four nest... on the island. However, the populations on Little Barrier and Codfish islands are...

  5. Cool, cold or colder? Spatial segregation of prions and blue petrels is explained by differences in preferred sea surface temperatures

    PubMed Central

    Quillfeldt, Petra; Cherel, Yves; Delord, Karine; Weimerkirch, Henri

    2015-01-01

    The Southern Ocean provides one of the largest environmental gradients on Earth that lacks geographical barriers, and small but highly mobile petrels living there may offer fine models of evolution of diversity along environmental gradients. Using geolocation devices, we investigated the winter distribution of closely related petrel species breeding sympatrically in the southern Indian Ocean, and applied ecological niche models to compare environmental conditions in the habitat used. We show that thin-billed prions (Pachyptila belcheri), Antarctic prions (Pachyptila desolata) and blue petrels (Halobaena caerulea) from the Kerguelen archipelago in the southern Indian Ocean segregate latitudinally, sea surface temperature being the most important variable separating the distribution of the species. Antarctic prions spent the winter north of the Polar Front in temperate waters, whereas blue petrels were found south of the Polar Front in Antarctic waters. Thin-billed prions preferred intermediate latitudes and temperatures. Stable isotope values of feathers reflected this near complete niche separation across an ecological gradient that spans large scales, and suggest evolutionary isolation by environment. In pelagic seabirds that exploit large areas of ocean, spatial niche partitioning may not only facilitate coexistence among ecologically similar species, but may also have driven their evolution in the absence of geographical barriers. PMID:25878044

  6. Cool, cold or colder? Spatial segregation of prions and blue petrels is explained by differences in preferred sea surface temperatures.

    PubMed

    Quillfeldt, Petra; Cherel, Yves; Delord, Karine; Weimerkirch, Henri

    2015-04-01

    The Southern Ocean provides one of the largest environmental gradients on Earth that lacks geographical barriers, and small but highly mobile petrels living there may offer fine models of evolution of diversity along environmental gradients. Using geolocation devices, we investigated the winter distribution of closely related petrel species breeding sympatrically in the southern Indian Ocean, and applied ecological niche models to compare environmental conditions in the habitat used. We show that thin-billed prions (Pachyptila belcheri), Antarctic prions (Pachyptila desolata) and blue petrels (Halobaena caerulea) from the Kerguelen archipelago in the southern Indian Ocean segregate latitudinally, sea surface temperature being the most important variable separating the distribution of the species. Antarctic prions spent the winter north of the Polar Front in temperate waters, whereas blue petrels were found south of the Polar Front in Antarctic waters. Thin-billed prions preferred intermediate latitudes and temperatures. Stable isotope values of feathers reflected this near complete niche separation across an ecological gradient that spans large scales, and suggest evolutionary isolation by environment. In pelagic seabirds that exploit large areas of ocean, spatial niche partitioning may not only facilitate coexistence among ecologically similar species, but may also have driven their evolution in the absence of geographical barriers.

  7. Characterization of MHC class I and II genes in a subantarctic seabird, the blue petrel, Halobaena caerulea (Procellariiformes).

    PubMed

    Strandh, Maria; Lannefors, Mimi; Bonadonna, Francesco; Westerdahl, Helena

    2011-10-01

    The great polymorphism observed in the major histocompatibility complex (MHC) genes is thought to be maintained by pathogen-mediated selection possibly combined with MHC-disassortative mating, guided by MHC-determined olfactory cues. Here, we partly characterize the MHC class I and II B of the blue petrel, Halobaena caerulea (Procellariiformes), a bird with significant olfactory abilities that lives under presumably low pathogen burdens in Subantarctica. Blue petrels are long-lived, monogamous birds which suggest the necessity of an accurate mate choice process. The species is ancestral to songbirds (Passeriformes; many MHC loci), although not to gamefowls (Galliformes; few MHC loci). Considering the phylogenetic relationships and the low subantarctic pathogen burden, we expected few rather than many MHC loci in the blue petrel. However, when we analysed partial MHC class I and class II B cDNA and gDNA sequences we found evidence for as many as at least eight MHC class I loci and at least two class II B loci. These class I and II B sequences showed classical MHC characteristics, e.g. high nucleotide diversity, especially in putative peptide-binding regions where signatures of positive selection was detected. Trans-species polymorphism was found between MHC class II B sequences of the blue petrel and those of thin-billed prion, Pachyptila belcheri, two species that diverged ∼25 MYA. The observed MHC allele richness in the blue petrel may well serve as a basis for mate choice, especially since olfactory discrimination of MHC types may be possible in this species. PMID:21607694

  8. Megachile timberlakei Cockerell (Hymenoptera: Megachilidae): Yet another adventive bee species to the Galapagos Archipelago

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Galapagos Archipelago has been thought to be extremely depauperate in bees, with only one species known, Xylocopa darwini. Recently a second species, Anthidium vigintiduopunctatum, was detected. Here we document a third species, Megachile timberlakei. We provide floral records as well as a dia...

  9. Anthidium vigintiduopunctatum Friese (Hymenoptera: Megachilidae): The elusive "dwarf bee" of the Galapagos Archipelago

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The endemic large carpenter bee, Xylocopa darwini Cockerell, was the only known bee pollinator to the Galapagos Archipelago but as early as 1964 locals also spoke of the "dwarf bee of Floreana". We report the presence of the wool carder bee, Anthidium vigintiduopunctatum Friese, on the island of Fl...

  10. Long-term isolation of a highly mobile seabird on the Galapagos

    USGS Publications Warehouse

    Hailer, Frank; Schreiber, E.A.; Miller, Joshua M.; Levin, Iris I.; Parker, Patricia G.; Chesser, R. Terry; Fleischer, Robert C.

    2011-01-01

    The Galapagos Islands are renowned for their high degree of endemism. Marine taxa inhabiting the archipelago might be expected to be an exception, because of their utilization of pelagic habitats--the dispersal barrier for terrestrial taxa--as foraging grounds. Magnificent frigatebirds (Fregata magnificens) have a highly vagile lifestyle and wide geographical distribution around the South and Central American coasts. Given the potentially high levels of gene flow among populations, the species provides a good test of the effectiveness of the Galapagos ecosystem in isolating populations of highly dispersive marine species. We studied patterns of genetic (mitochondrial DNA, microsatellites and nuclear introns) and morphological variation across the distribution of magnificent frigatebirds. Concordant with predictions from life-history traits, we found signatures of extensive gene flow over most of the range, even across the Isthmus of Panama, which is a major barrier to gene flow in other tropical seabirds. In contrast, individuals from the Galapagos were strongly differentiated from all conspecifics, and have probably been isolated for several hundred thousand years. Our finding is a powerful testimony to the evolutionary uniqueness of the taxa inhabiting the Galapagos archipelago and its associated marine ecosystems.

  11. Radiometric ages of brachyuran crabs from the Galapagos spreading-center hydrothermal ventfield

    SciTech Connect

    Bennett, J.T.; Turekian, K.K.

    1984-09-01

    The ages of four crab carapaces from the Galapagos spreading-center hydrothermal ventfield were determined radiometrically using members of the U and Th decay chains. One animal had an age of 0.1 years and therefore had undergone molting just before collection; the other three had last molted 3-4 years before collection.

  12. Long-term isolation of a highly mobile seabird on the Galapagos

    PubMed Central

    Hailer, Frank; Schreiber, E. A.; Miller, Joshua M.; Levin, Iris I.; Parker, Patricia G.; Chesser, R. Terry; Fleischer, Robert C.

    2011-01-01

    The Galapagos Islands are renowned for their high degree of endemism. Marine taxa inhabiting the archipelago might be expected to be an exception, because of their utilization of pelagic habitats—the dispersal barrier for terrestrial taxa—as foraging grounds. Magnificent frigatebirds (Fregata magnificens) have a highly vagile lifestyle and wide geographical distribution around the South and Central American coasts. Given the potentially high levels of gene flow among populations, the species provides a good test of the effectiveness of the Galapagos ecosystem in isolating populations of highly dispersive marine species. We studied patterns of genetic (mitochondrial DNA, microsatellites and nuclear introns) and morphological variation across the distribution of magnificent frigatebirds. Concordant with predictions from life-history traits, we found signatures of extensive gene flow over most of the range, even across the Isthmus of Panama, which is a major barrier to gene flow in other tropical seabirds. In contrast, individuals from the Galapagos were strongly differentiated from all conspecifics, and have probably been isolated for several hundred thousand years. Our finding is a powerful testimony to the evolutionary uniqueness of the taxa inhabiting the Galapagos archipelago and its associated marine ecosystems. PMID:20861041

  13. Coastal Impacts of the March 11th Tsunami in the Galapagos Islands

    NASA Astrophysics Data System (ADS)

    Lynett, P. J.; Weiss, R.; Renteria, W.

    2011-12-01

    On March 11, 2011 at 5:46:23 UTC (March 10 11:46:23 PM Local Time, Galapagos), the magnitude 9.0 Mw Great East Japan Earthquake occurred near the Tohoku region off the east coast of Japan. The purpose of this presentation is to provide the results of a tsunami field survey in the Galapagos Islands performed by an International Tsunami Survey Team (ITST) with great assistance from INOCAR, the oceanographic service of the Ecuadorian Navy, and the Galapagos National Park. The Galapagos Islands are a volcanic chain composed of many islands of various sizes. The four largest islands are the focus of this survey, and are, from west to east, Isabela, Santiagio, Santa Cruz, and San Cristobal. Aside from approximately 10 sandy beaches that are open to tourists, all other shoreline locations are strictly off limits to anyone without a research permit. All access to the shoreline is coordinated through the Galapagos National Park, and any landing requires a chaperone, a Park Ranger. While a few of the visited areas in this survey were tourist sites, the vast majority were not. Due to time constraints and a generally inaccessibility of the coastline, the survey locations were strongly guided by numerical computations performed previous to the surveys. This numerical guidance accurately predicted the regions of highest impact, as well as regions of relatively low impact. Tide-corrected maximum flow elevations were generally in the range of 3-4 meters, while Isabela experienced the largest flow elevation of 6 m in a small pocket beach. The largest harbor in the Islands, Puerto Ayora, experienced moderate damage, with significant flooding and some structural damage. Currents in the Baltra Channel, a small waterway between Santa Cruz and Baltra, were strong enough to transport navigation buoys distances greater than 800 m. Extreme dune erosion, and the associated destruction of sea turtle nesting habit, was widespread and noted on all of the islands visited.

  14. An Extensive Alien Plant Inventory from the Inhabited Areas of Galapagos

    PubMed Central

    Guézou, Anne; Trueman, Mandy; Buddenhagen, Christopher Evan; Chamorro, Susana; Guerrero, Ana Mireya; Pozo, Paola; Atkinson, Rachel

    2010-01-01

    Background Plant invasions are causing habitat degradation in Galapagos. Problems are concentrated on the four inhabited islands. Plants introduced to rural areas in the humid highlands and urban areas on the arid coast act as foci for invasion of the surrounding Galapagos National Park. Methodology/Principal Findings Here we present results of the most comprehensive inventory to date of alien vascular plants in the inhabited areas of Galapagos. The survey was conducted between 2002 and 2007, in 6031 properties (97% of the total) on Floreana, Isabela, San Cristobal and Santa Cruz Islands. In total 754 alien vascular plant taxa were recorded, representing 468 genera in 123 families. Dicotyledons represented 554 taxa, monocotyledons 183, there were 7 gymnosperms and 10 pteridophytes. Almost half (363) of the taxa were herbaceous. The most represented families were Fabaceae (sensu lato), Asteraceae and Poaceae. The three most recorded species in the humid rural areas were Psidium guajava, Passiflora edulis and Bryophyllum pinnatum, and in the dry urban areas, Aloe vera, Portulaca oleracea and Carica papaya. In total, 264 (35%) taxa were recorded as naturalized. The most common use for taxa was ornamental (52%). Conclusions/Significance This extensive survey has increased the known alien vascular flora of Galapagos by 257 species, giving a ratio of alien to native taxa of 1.57∶1. It provides a crucial baseline for plant invasion management in the archipelago and contributes data for meta analyses of invasion processes worldwide. A repeat of the survey in the future would act as an effective early detection tool to help avoid further invasion of the Galapagos National Park. PMID:20421999

  15. Local parasite lineage sharing in temperate grassland birds provides clues about potential origins of Galapagos avian Plasmodium.

    PubMed

    Levin, Iris I; Colborn, Rachel E; Kim, Daniel; Perlut, Noah G; Renfrew, Rosalind B; Parker, Patricia G

    2016-02-01

    Oceanic archipelagos are vulnerable to natural introduction of parasites via migratory birds. Our aim was to characterize the geographic origins of two Plasmodium parasite lineages detected in the Galapagos Islands and in North American breeding bobolinks (Dolichonyx oryzivorus) that regularly stop in Galapagos during migration to their South American overwintering sites. We used samples from a grassland breeding bird assemblage in Nebraska, United States, and parasite DNA sequences from the Galapagos Islands, Ecuador, to compare to global data in a DNA sequence registry. Homologous DNA sequences from parasites detected in bobolinks and more sedentary birds (e.g., brown-headed cowbirds Molothrus ater, and other co-occurring bird species resident on the North American breeding grounds) were compared to those recovered in previous studies from global sites. One parasite lineage that matched between Galapagos birds and the migratory bobolink, Plasmodium lineage B, was the most common lineage detected in the global MalAvi database, matching 49 sequences from unique host/site combinations, 41 of which were of South American origin. We did not detect lineage B in brown-headed cowbirds. The other Galapagos-bobolink match, Plasmodium lineage C, was identical to two other sequences from birds sampled in California. We detected a close variant of lineage C in brown-headed cowbirds. Taken together, this pattern suggests that bobolinks became infected with lineage B on the South American end of their migratory range, and with lineage C on the North American breeding grounds. Overall, we detected more parasite lineages in bobolinks than in cowbirds. Galapagos Plasmodium had similar host breadth compared to the non-Galapagos haemosporidian lineages detected in bobolinks, brown-headed cowbirds, and other grassland species. This study highlights the utility of global haemosporidian data in the context of migratory bird-parasite connectivity. It is possible that migratory bobolinks

  16. Spatial distribution and ecological niches of non-breeding planktivorous petrels

    PubMed Central

    Navarro, Joan; Cardador, Laura; Brown, Ruth; Phillips, Richard A.

    2015-01-01

    According to niche theory, mechanisms exist that allow co-existence of organisms that would otherwise compete for the same prey and other resources. How seabirds cope with potential competition during the non-breeding period is poorly documented, particularly for small species. Here we investigate for the first time the potential role of spatial, environmental (habitat) and trophic (isotopic) segregation as niche-partitioning mechanisms during the non-breeding season for four species of highly abundant, zooplanktivorous seabird that breed sympatrically in the Southern Ocean. Spatial segregation was found to be the main partitioning mechanism; even for the two sibling species of diving petrel, which spent the non-breeding period in overlapping areas, there was evidence from distribution and stable isotope ratios for differences in habitat use and diving depth. PMID:26165162

  17. Effects of warm sea-surface temperature anomalies on the blue petrel at the Kerguelen Islands

    PubMed Central

    Guinet, C.; Chastel, O.; Koudil, M.; Durbec, J. P.; Jouventin, P.

    1998-01-01

    Several long-term studies on Southern Ocean seabirds and seals have suggested a possible link between major declines in breeding performance and El Niño Southern Oscillation events. We report that the breeding performances and body condition of the blue petrel (Halobaena carulea) on the Kerguelen Islands is depressed by episodic, warm sea-surface temperatures (SSTs) in the winter before breeding. Lagged cross correlations between SSTs in the Kerguelen sector and the Southern Oscillation Index indicate that warm SSTs were found south of Kerguelen Islands within a year of, and between 4.2 and 5.4 years after, an El Niño event took place. These results can be discussed with respect to the recently described Antarctic Circumpolar Wave that drives climatic anomalies eastward around the Southern Ocean.

  18. Spatial distribution and ecological niches of non-breeding planktivorous petrels.

    PubMed

    Navarro, Joan; Cardador, Laura; Brown, Ruth; Phillips, Richard A

    2015-01-01

    According to niche theory, mechanisms exist that allow co-existence of organisms that would otherwise compete for the same prey and other resources. How seabirds cope with potential competition during the non-breeding period is poorly documented, particularly for small species. Here we investigate for the first time the potential role of spatial, environmental (habitat) and trophic (isotopic) segregation as niche-partitioning mechanisms during the non-breeding season for four species of highly abundant, zooplanktivorous seabird that breed sympatrically in the Southern Ocean. Spatial segregation was found to be the main partitioning mechanism; even for the two sibling species of diving petrel, which spent the non-breeding period in overlapping areas, there was evidence from distribution and stable isotope ratios for differences in habitat use and diving depth. PMID:26165162

  19. Climate driven life histories: the case of the Mediterranean storm petrel.

    PubMed

    Soldatini, Cecilia; Albores-Barajas, Yuri Vladimir; Massa, Bruno; Gimenez, Olivier

    2014-01-01

    Seabirds are affected by changes in the marine ecosystem. The influence of climatic factors on marine food webs can be reflected in long-term seabird population changes. We modelled the survival and recruitment of the Mediterranean storm petrel (Hydrobates pelagicus melitensis) using a 21-year mark-recapture dataset involving almost 5000 birds. We demonstrated a strong influence of prebreeding climatic conditions on recruitment age and of rainfall and breeding period conditions on juvenile survival. The results suggest that the juvenile survival rate of the Mediterranean subspecies may not be negatively affected by the predicted features of climate change, i.e., warmer summers and lower rainfall. Based on considerations of winter conditions in different parts of the Mediterranean, we were able to draw inferences about the wintering areas of the species for the first time. PMID:24728099

  20. Injuries to avian researchers at Palmer Station, Antarctica from penguins, giant petrels, and skuas.

    PubMed

    Bovard, R S

    2000-01-01

    This paper describes 5 cases of injury to seabird researchers between 1996 and 1999 at Palmer Station, Antarctica. The injuries were inflicted by 3 seabird species: the Adelie penguin (Pygoscelis adeliae); the southern giant petrel (Macronectes giganteus); and the brown skua (Catharacta lonnbergi). All injured parties were biologic researchers with previous field experience working under National Science Foundation research grants; all sought medical evaluation and treatment voluntarily. The nature and frequency of such injuries seems not to have been greatly reported in the medical literature. Although these cases were largely soft tissue injuries that healed without serious complications, the possibility of exotic infections is considered. We have dubbed this constellation of injuries AVES (Antarctic Vogel [German for bird] Encounter Syndrome). PMID:10921359

  1. Climate driven life histories: the case of the Mediterranean storm petrel.

    PubMed

    Soldatini, Cecilia; Albores-Barajas, Yuri Vladimir; Massa, Bruno; Gimenez, Olivier

    2014-01-01

    Seabirds are affected by changes in the marine ecosystem. The influence of climatic factors on marine food webs can be reflected in long-term seabird population changes. We modelled the survival and recruitment of the Mediterranean storm petrel (Hydrobates pelagicus melitensis) using a 21-year mark-recapture dataset involving almost 5000 birds. We demonstrated a strong influence of prebreeding climatic conditions on recruitment age and of rainfall and breeding period conditions on juvenile survival. The results suggest that the juvenile survival rate of the Mediterranean subspecies may not be negatively affected by the predicted features of climate change, i.e., warmer summers and lower rainfall. Based on considerations of winter conditions in different parts of the Mediterranean, we were able to draw inferences about the wintering areas of the species for the first time.

  2. Evidence that blue petrel, Halobaena caerulea, fledglings can detect and orient to dimethyl sulfide.

    PubMed

    Bonadonna, F; Caro, S; Jouventin, P; Nevitt, G A

    2006-06-01

    Procellariiform seabirds (the petrels, albatrosses and shearwaters) are recognized for their acute sense of smell. These pelagic seabirds forage over thousands of miles of ocean to find patchily distributed prey resources. Over the past decade, much headway has been made in unravelling the variety of olfactory foraging strategies that Antarctic species employ, and it is becoming clearer that olfaction plays a key role in foraging, particularly for burrow nesting species. Now we are beginning to explore how these behaviours develop in chicks. Procellariiform chicks fledge and survive the open seas without aid or instruction from a parent, but how they are able to accomplish this task is unknown. Here we explore whether chicks leave the nest pre-tuned to olfactory cues necessary for foraging. In this study, we tested the hypothesis that blue petrel chicks (Halobaena caerulea) are able to detect and orient to a foraging cue (dimethyl sulphide, DMS) used by adults without ever having experienced this odour at sea. We first established that chicks could detect DMS at a biologically relevant concentration that they will later naturally encounter at sea (<10 pmol l-1). We then performed preference tests in a Y-maze on a group of birds 1-6 days before they fledged. Sixteen out of 20 fledglings preferred DMS (e.g. DMS+propylene glycol) to a ;control' odour (propylene glycol alone). Our results suggest that chicks can detect and may already recognize DMS as an orientation cue even before they leave the nest to forage for the first time. PMID:16709918

  3. Effects of the exxon valdez oil spill on fork-tailed storm-petrels breeding in the Barren Islands, Alaska. Bird study number 7. Exxon Valdez oil spill state/federal natural resource damage assessment final report

    SciTech Connect

    Nishimoto, M.; Byrd, G.V.

    1993-04-01

    We evaluated fork-tailed storm-petrels (Oceanodroma furcata) at East Amatuli Island, Barren Islands, the largest storm-petrel breeding colony within the trajectory of the oil slick, to determine whether there was evidence of adverse effects, following the 1989 Exxon Valdex oil spill. Although we were unable to measure all possible indicators, we found insufficient evidence to conclude that there were significant adverse impacts to breeding storm-petrels in 1989.

  4. The Role of Plume-Ridge Interaction in Magma Genesis II: Wolf Island, Galapagos

    NASA Astrophysics Data System (ADS)

    Blair, S. W.; Harpp, K. S.; Reed, L. A.; Koleszar, A. M.

    2002-12-01

    Wolf Island is one of two isolated volcanoes in the NW Galapagos Archipelago. Along with Darwin Island and several seamounts, Wolf is part of an intriguingly linear bathymetric feature (Wolf-Darwin Lineament, WDL) that trends 140o between the Galapagos Spreading Center (GSC) and the main archipelago. Because Wolf is located only 60 km south of the GSC and <200 km north of Fernandina, the most active volcano in the region, Wolf is effectively upstream of the plume center relative to plate motion and not easily explained in the context of a traditional plume model. Most recently, the WDL has been proposed to be the result of tensional stresses caused by the transform fault at 91oW, allowing underlying magmatic material to erupt along these zones of weakness. Despite its small sub-aerial extent (<5 km2), Wolf has a complex volcanic history, including at least two major eruptive phases. First, the southern part of the island is constructed of horizontal, 1-2 m thick basalt flows. Next, thicker (2-8 m), flat-lying flows erupted after a significant hiatus in activity. Their eruption resulted in a caldera, now eroded to form a bay. Wolf has produced plagioclase ultraphyric basalts throughout its history, with up to 60% plagioclase and crystals nearly 4 cm long. Such basalts are typical of islands from the northern Galapagos and are rarely observed elsewhere. Unlike the other northern islands, however, ultraphyric flows constitute a major fraction of Wolf's sub-aerial volume. Megacrysts are segregated into bands within the thicker flows and are more abundant in the most recently erupted material. Wolf lavas exhibit some of the most extreme compositional variations observed at a single volcano in the Galapagos, from slightly less enriched than Fernandina to MORB-like depletion. The enriched signatures confirm that plume material is a major component in the mantle underlying the northern Galapagos, likely the result of magmatic communication with the GSC. Early in Wolf

  5. A case study of human migration and the sea cucumber crisis in the Galapagos Islands.

    PubMed

    Bremner, Jason; Perez, Jaime

    2002-06-01

    The sea cucumber fishing crisis in Galapagos is an example of the potential consequences of rapid migration, growing economic competition, and weak regulatory mechanisms. In a short period of time sea cucumber fishing has become the most inflammatory issue in the Galapagos. The key factors that allowed for the efficient exploitation of the new resource were not the fishermen themselves but rather the new fishing techniques and access to credit and markets. This suggests that the annual sea cucumber crisis is due to factors more complex than simply more fishermen generating greater sea cucumber catches. This paper examines census data and fisher registries to analyze population growth in the islands. A public opinion survey is used to determine the population's attitudes toward sea cucumber fishing and regulations. Qualitative interviews explore the history of the sea cucumber boom. Information from the sea cucumber monitoring program provides estimates for the annual sea cucumber catches. PMID:12174601

  6. Definition of basin phases in the Petrel Sub-basin (Australia): Implications for the development of Palaeozoic petroleum systems

    SciTech Connect

    Blevin, J.E.; Colwell, J.B.; Kennard, J.M. , Canberra )

    1996-01-01

    An study of the Petrel Sub-basin (Bonaparte Basin) on Australia's northwest margin has identified seven main phases of basin development spanning the Early Cambrian to Tertiary. Each phase was initiated and terminated by distinct, primarily tectonic events that have controlled the structural and stratigraphic evolution of the basin and the development of petroleum systems. These phases include periods of major extension (Early Cambrian, Middle Devonian to early Carboniferous) and compression (Early Devonian, mid-Triassic), as well as rapid and slow subsidence phases in the Early to Late Carboniferous and Late Carboniferous to Triassic, respectively. Basin inversion in the mid-Triassic has been critical in controlling the development of broad anticlinal features that presently reservoir the large, but as yet undeveloped gas/condensate fields Petrel and Tern. An earlier period of minor compression during the late Carboniferous initiated limited movement of Paleozoic salt within the deeper basin, forming salt-cored, low amplitude anticlines in the predominantly carbonate Tanmurra Formation, a play which remains untested. In the southern Petrel Sub-basin, early phases of hydrocarbon generation and fluid migration associated with salt movement are poorly understood. Preliminary results of geochemical studies indicate that there are at least two oil families in Devonian and Carboniferous reservoirs. This suggests multiple source intervals within the deeper flanks of the basin, thus the understanding of sedimentation during early basin phases may be critical in evaluating petroleum systems.

  7. Definition of basin phases in the Petrel Sub-basin (Australia): Implications for the development of Palaeozoic petroleum systems

    SciTech Connect

    Blevin, J.E.; Colwell, J.B.; Kennard, J.M.

    1996-12-31

    An study of the Petrel Sub-basin (Bonaparte Basin) on Australia`s northwest margin has identified seven main phases of basin development spanning the Early Cambrian to Tertiary. Each phase was initiated and terminated by distinct, primarily tectonic events that have controlled the structural and stratigraphic evolution of the basin and the development of petroleum systems. These phases include periods of major extension (Early Cambrian, Middle Devonian to early Carboniferous) and compression (Early Devonian, mid-Triassic), as well as rapid and slow subsidence phases in the Early to Late Carboniferous and Late Carboniferous to Triassic, respectively. Basin inversion in the mid-Triassic has been critical in controlling the development of broad anticlinal features that presently reservoir the large, but as yet undeveloped gas/condensate fields Petrel and Tern. An earlier period of minor compression during the late Carboniferous initiated limited movement of Paleozoic salt within the deeper basin, forming salt-cored, low amplitude anticlines in the predominantly carbonate Tanmurra Formation, a play which remains untested. In the southern Petrel Sub-basin, early phases of hydrocarbon generation and fluid migration associated with salt movement are poorly understood. Preliminary results of geochemical studies indicate that there are at least two oil families in Devonian and Carboniferous reservoirs. This suggests multiple source intervals within the deeper flanks of the basin, thus the understanding of sedimentation during early basin phases may be critical in evaluating petroleum systems.

  8. Hybridization and Back-Crossing in Giant Petrels (Macronectes giganteus and M. halli) at Bird Island, South Georgia, and a Summary of Hybridization in Seabirds

    PubMed Central

    Brown, Ruth M.; Techow, N. M. S. Mareile; Wood, Andrew G.; Phillips, Richard A.

    2015-01-01

    Hybridization in natural populations provides an opportunity to study the evolutionary processes that shape divergence and genetic isolation of species. The emergence of pre-mating barriers is often the precursor to complete reproductive isolation. However, in recently diverged species, pre-mating barriers may be incomplete, leading to hybridization between seemingly distinct taxa. Here we report results of a long-term study at Bird Island, South Georgia, of the extent of hybridization, mate fidelity, timing of breeding and breeding success in mixed and conspecific pairs of the sibling species, Macronectes halli (northern giant petrel) and M. giganteus (southern giant petrel). The proportion of mixed-species pairs varied annually from 0.4–2.4% (mean of 1.5%), and showed no linear trend with time. Mean laying date in mixed-species pairs tended to be later than in northern giant petrel, and always earlier than in southern giant petrel pairs, and their breeding success (15.6%) was lower than that of conspecific pairs. By comparison, mixed-species pairs at both Marion and Macquarie islands always failed before hatching. Histories of birds in mixed-species pairs at Bird Island were variable; some bred previously or subsequently with a conspecific partner, others subsequently with a different allospecific partner, and some mixed-species pairs remained together for multiple seasons. We also report the first verified back-crossing of a hybrid giant petrel with a female northern giant petrel. We discuss the potential causes and evolutionary consequences of hybridization and back-crossing in giant petrels and summarize the incidence of back-crossing in other seabird species. PMID:25815478

  9. Hybridization and back-crossing in giant petrels (Macronectes giganteus and M. halli) at Bird Island, South Georgia, and a summary of hybridization in seabirds.

    PubMed

    Brown, Ruth M; Techow, N M S Mareile; Wood, Andrew G; Phillips, Richard A

    2015-01-01

    Hybridization in natural populations provides an opportunity to study the evolutionary processes that shape divergence and genetic isolation of species. The emergence of pre-mating barriers is often the precursor to complete reproductive isolation. However, in recently diverged species, pre-mating barriers may be incomplete, leading to hybridization between seemingly distinct taxa. Here we report results of a long-term study at Bird Island, South Georgia, of the extent of hybridization, mate fidelity, timing of breeding and breeding success in mixed and conspecific pairs of the sibling species, Macronectes halli (northern giant petrel) and M. giganteus (southern giant petrel). The proportion of mixed-species pairs varied annually from 0.4-2.4% (mean of 1.5%), and showed no linear trend with time. Mean laying date in mixed-species pairs tended to be later than in northern giant petrel, and always earlier than in southern giant petrel pairs, and their breeding success (15.6%) was lower than that of conspecific pairs. By comparison, mixed-species pairs at both Marion and Macquarie islands always failed before hatching. Histories of birds in mixed-species pairs at Bird Island were variable; some bred previously or subsequently with a conspecific partner, others subsequently with a different allospecific partner, and some mixed-species pairs remained together for multiple seasons. We also report the first verified back-crossing of a hybrid giant petrel with a female northern giant petrel. We discuss the potential causes and evolutionary consequences of hybridization and back-crossing in giant petrels and summarize the incidence of back-crossing in other seabird species. PMID:25815478

  10. An Earthquake Swarm on the Galapagos Transform Fault: Implications for Earthquake Triggering

    NASA Astrophysics Data System (ADS)

    Roland, E.; Boettcher, M. S.; McGuire, J. J.

    2004-12-01

    Transform faults on the East Pacific Rise spreading system often have large amounts of seismicity in short periods of time. The magnitude vs. time distribution of these sequences ranges from what would be classified as similar to a typical continental earthquake but with an elevated foreshock to aftershock ratio to sequences that would traditionally be classified as an "earthquake swarm" closer to those seen in volcanic regions (e.g. Forsyth et al., 2003). Analysis of declustered earthquake catalogs (i.e. ignoring the swarms) suggest that the anomalous foreshock to aftershock ratio on EPR transforms requires different triggering processes in the oceanic regime from those that explain continental seismicity. Here we investigate the best recorded earthquake swarm on an EPR transform to evaluate whether it has similar implications. Due to the lack of oceanic earthquake catalogs with low detection thresholds and reliable magnitude estimates, the unique characteristics of transform sequences have been difficult to quantify. This study uses the earthquake catalog derived from NOAA's hydroacoustic array in the equatorial Pacific Ocean and data from a land-based seismometer array on the Galapagos Islands (from Toomey et al.) to examine the temporal and size distribution of an earthquake swarm which occurred on the Galapagos Transform in 2000. Seismic moment estimates are determined with a high degree of accuracy using an Empirical Green's Function based, cross-correlation method. Characteristics of the Galapagos swarm can be compared to that normally observed in continental strike-slip faults by applying the Epidemic Type Aftershock Sequence (ETAS) Model [e.g. Helmstetter and Sorenette, 2002], which is a common earthquake triggering model used to explain continental seismicity. This model assumes aftershocks are triggered from all large earthquakes with a triggering rate that decays in time following the Omori Law and increases with triggering event magnitude. The utility

  11. Coastal Impacts of the March 11th Tohoku, Japan Tsunami in the Galapagos Islands

    NASA Astrophysics Data System (ADS)

    Lynett, Patrick; Weiss, Robert; Renteria, Willington; De La Torre Morales, Giorgio; Son, Sangyoung; Arcos, Maria Elizabeth Martin; MacInnes, Breanyn Tiel

    2013-06-01

    On March 11, 2011 at 5:46:23 UTC (March 10 11:46:23 PM Galapagos Local Time), the Mw 9.0 Great East Japan Earthquake occurred near the Tohoku region off the east coast of Japan, spawning a Pacific-wide tsunami. Approximately 12,000 km away, the Galapagos Islands experienced moderate tsunami impacts, including flooding, structural damage, and strong currents. In this paper, we present observations and measurements of the tsunami effects in the Galapagos, focusing on the four largest islands in the archipelago; (from west to east) Isabela, Santiagio, Santa Cruz, and San Cristobal. Access to the tsunami affected areas was one of the largest challenges of the field survey. Aside from approximately ten sandy beaches open to tourists, all other shoreline locations are restricted to anyone without a research permit; open cooperation with the Galapagos National Park provided the survey team complete access to the Islands coastlines. Survey locations were guided by numerical simulations of the tsunami performed prior to the field work. This numerical guidance accurately predicted the regions of highest impact, as well as regions of relatively low impact. Tide-corrected maximum tsunami heights were generally in the range of 3-4 m with the highest runup of 6 m measured in a small pocket beach on Isla Isabela. Puerto Ayora, on Santa Cruz Island, the largest harbor in the Galapagos experienced significant flooding and damage to structures located at the shoreline. A current meter moored inside the harbor recorded relatively weak tsunami currents of less than 0.3 m/s (0.6 knot) during the event. Comparisons with detailed numerical simulations suggest that these low current speed observations are most likely the result of data averaging at 20-min intervals and that maximum instantaneous current speeds were considerably larger. Currents in the Canal de Itabaca, a natural waterway between Santa Cruz Island and a smaller island offshore, were strong enough to displace multiple 5

  12. The Evolution of Floreana Island, Galapagos: Mantle Metasomatism as a Control of Structural and Geochemical Variations

    NASA Astrophysics Data System (ADS)

    Koleszar, A. M.; Rollins, N. A.; Harpp, K. S.; Geist, D. J.

    2004-05-01

    Floreana, the 6th largest island in the Galapagos Archipelago, is situated ESE of the current proposed location of the hotspot, believed to be near Fernandina Island. Floreana is the most distant Galapagos volcano from the Galapagos Spreading Center and is located on 12 Ma lithosphere. Both normally- and reversely-polarized flows are present on Floreana, which emerged more than 1 Ma. The emergent shield is constructed of lava flows and >80 cinder cones. In the final stage of island building, approximately 0.3 Ma, the eruptive activity on Floreana became more explosive and produced the largest cinder cones on the island. Spatter ramparts, cinder cones, vents, and pit craters are arranged in at least 3 major parallel to sub-parallel alignments oriented N40E. The basalts of Floreana are notably alkalic, primitive, and highly enriched in incompatible trace elements (ITE). MgO concentrations in the lavas range from <8 wt% to >13 wt%, and many of the magmas are likely related by fractional crystallization of olivine and clinopyroxene. The volcano has erupted ultramafic xenoliths, which are observed predominantly in the older, reversely-polarized flows and cones. Floreana lavas have the greatest light REE enrichment observed in the archipelago and the most radiogenic Sr- and Pb- isotopic ratios, indicative of an ITE-enriched source. Elevated ratios of alkali and alkaline earth contents to those of high-field strength elements indicate contributions from metasomatic fluids to Floreana melts. Although the effects of metasomatism are apparent in most Floreana basalts, normally-polarized lavas may have been affected to a greater extent by the metasomatism than the older flows. Temporal-compositional trends in trace element concentrations also suggest that the depth of melt generation may have decreased slightly over the course of the island's formation. Floreana is distinct from the rest of the Galapagos Archipelago in its explosive history, abundant mantle xenoliths

  13. Speciation through temporal segregation of Madeiran storm petrel (Oceanodroma castro) populations in the Azores?

    PubMed Central

    Monteiro, L. R.

    1998-01-01

    Madeiran storm petrels Oceanodroma castro breed on three small islets in the Azores: Vila, off Santa Maria, and Praia and Baixo, off Graciosa. Analysis of data on brood patch, incubation periods, chick body size and recaptures of adults provides evidence of the existence of two distinct populations (hot- and cool-season) breeding annually on Baixo and Praia, out of phase by four to five months and overlapping in colony attendance during August and early September; on Vila only the cool-season population is present. Analyses of adult morphology indicate highly significant phenotypic differentiation between the sympatric hot- and cool-season breeders, whereas an almost complete phenotypic uniformity characterizes allopatric breeders within the same season. The hot-season birds are 10% smaller in egg and body mass but have longer wings and tails than cool-season birds. The two groups were readily separated by discriminant analysis. The preference to breed in the cooler season is interpreted as a consequence of greater food availability in that period. Morphological differentiation between seasonal populations is interpreted as an adaptative response to different environmental conditions in the two seasons. The hypothesis is given that the hot-season population has evolved from the cool-season population owing to density-dependent constraints on crowded colonies, forcing birds to time-share nest sites. These populations may represent a case of sympatric speciation through temporal partitioning of reproduction and may be better treated as sibling species.

  14. The pattern of circumferential and radial eruptive fissures on the volcanoes of Fernandina and Isabela islands, Galapagos

    USGS Publications Warehouse

    Chadwick, W.W.; Howard, K.A.

    1991-01-01

    Maps of the eruptive vents on the active shield volcanoes of Fernandina and Isabela islands, Galapagos, made from aerial photographs, display a distinctive pattern that consists of circumferential eruptive fissures around the summit calderas and radial fissures lower on the flanks. On some volcano flanks either circumferential or radial eruptions have been dominant in recent time. The location of circumferential vents outside the calderas is independent of caldera-related normal faults. The eruptive fissures are the surface expression of dike emplacement, and the dike orientations are interpreted to be controlled by the state of stress in the volcano. Very few subaerial volcanoes display a pattern of fissures similar to that of the Galapagos volcanoes. Some seamounts and shield volcanoes on Mars morphologically resemble the Galapagos volcanoes, but more specific evidence is needed to determine if they also share common structure and eruptive style. ?? 1991 Springer-Verlag.

  15. Molecular evidence for an old world origin of Galapagos and Caribbean band-winged grasshoppers (Acrididae: Oedipodinae: Sphingonotus).

    PubMed

    Husemann, Martin; Habel, Jan Christian; Namkung, Suk; Hochkirch, Axel; Otte, Daniel; Danley, Patrick D

    2015-01-01

    Patterns of colonization and diversification on islands provide valuable insights into evolutionary processes. Due to their unique geographic position and well known history, the Galapagos Islands are an important model system for evolutionary studies. Here we investigate the evolutionary history of a winged grasshopper genus to infer its origin and pattern of colonization in the Galapagos archipelago. The grasshopper genus Sphingonotus has radiated extensively in the Palaearctic and many species are endemic to islands. In the New World, the genus is largely replaced by the genus Trimerotropis. Oddly, in the Caribbean and on the Galapagos archipelago, two species of Sphingonotus are found, which has led to the suggestion that these might be the result of anthropogenic translocations from Europe. Here, we test this hypothesis using mitochondrial and nuclear DNA sequences from a broad sample of Sphingonotini and Trimerotropini species from the Old World and New World. The genetic data show two distinct genetic clusters representing the New World Trimerotropini and the Old World Sphingonotini. However, the Sphingonotus species from Galapagos and the Caribbean split basally within the Old World Sphingonotini lineage. The Galapagos and Caribbean species appear to be related to Old World taxa, but are not the result of recent anthropogenic translocations as revealed by divergence time estimates. Distinct genetic lineages occur on the four investigated Galapagos Islands, with deep splits among them compared to their relatives from the Palaearctic. A scenario of a past wider distribution of Sphingonotus in the New World with subsequent extinction on the mainland and replacement by Trimerotropis might explain the disjunct distribution.

  16. Molecular Evidence for an Old World Origin of Galapagos and Caribbean Band-Winged Grasshoppers (Acrididae: Oedipodinae: Sphingonotus)

    PubMed Central

    Husemann, Martin; Habel, Jan Christian; Namkung, Suk; Hochkirch, Axel; Otte, Daniel; Danley, Patrick D.

    2015-01-01

    Patterns of colonization and diversification on islands provide valuable insights into evolutionary processes. Due to their unique geographic position and well known history, the Galapagos Islands are an important model system for evolutionary studies. Here we investigate the evolutionary history of a winged grasshopper genus to infer its origin and pattern of colonization in the Galapagos archipelago. The grasshopper genus Sphingonotus has radiated extensively in the Palaearctic and many species are endemic to islands. In the New World, the genus is largely replaced by the genus Trimerotropis. Oddly, in the Caribbean and on the Galapagos archipelago, two species of Sphingonotus are found, which has led to the suggestion that these might be the result of anthropogenic translocations from Europe. Here, we test this hypothesis using mitochondrial and nuclear DNA sequences from a broad sample of Sphingonotini and Trimerotropini species from the Old World and New World. The genetic data show two distinct genetic clusters representing the New World Trimerotropini and the Old World Sphingonotini. However, the Sphingonotus species from Galapagos and the Caribbean split basally within the Old World Sphingonotini lineage. The Galapagos and Caribbean species appear to be related to Old World taxa, but are not the result of recent anthropogenic translocations as revealed by divergence time estimates. Distinct genetic lineages occur on the four investigated Galapagos Islands, with deep splits among them compared to their relatives from the Palaearctic. A scenario of a past wider distribution of Sphingonotus in the New World with subsequent extinction on the mainland and replacement by Trimerotropis might explain the disjunct distribution. PMID:25692768

  17. New Insights into the Morphology of the Galapagos Platform from Lower Crustal Flow Models

    NASA Astrophysics Data System (ADS)

    Orellana Rovirosa, F.; Richards, M. A.

    2014-12-01

    The volcanically-active Galapagos Islands are constructed upon a broad platform, with the westernmost islands being the most active, marking the present-day position of the Galapagos hotspot (mantle plume). This volcanic platform overlies relatively young oceanic lithosphere (<15 Myr) and exhibits unique morphologic features along its boundaries. The most spectacular of these features is a system of stepped terraces on the southwestern escarpment, with very large vertical relief (>3 km), and contrasting with relatively gentle slopes off the eastern platform edge toward the Carnegie ridge. Considering the horizontal lithostatic pressure differences associated with this bathymetric relief, along with the high temperatures within this young, hotspot-affected oceanic lithosphere and crust; it is likely that lower crustal flow contributes significantly, perhaps even dominantly, to lithospheric and crustal deformation within the Galapagos Platform. Using 2D numerical models that invoke a thin-sheet approximation for the Stokes' equation for a Newtonian fluid with space- and time-dependent viscosity, and assuming isostatic conditions, we show that: (1) the pronounced bathymetric rim along the Eastern platform region (where gravimetric studies indicate Airy isostasy) near Española Island may be the expression of a mature stage of a lower crustal flow front evolving asymptotically during the last ~3 Myr; (2) the spectacular system of stepped terraces along the southwestern edge of the platform may be explained by lower crustal flow-associated backward tilting of the bathymetric surface that, even with small amounts of angular change (~0.1 deg) and potentially occurring in non-isostatic regimes, effectively hinders the horizontal flow of lava. This process of backward-tilting may have been largely restricted to the last ~1 Myr of platform growth, and hence may be a unique event that may involve horizontal extrusion of large lava sheets from within the southwestward

  18. Catch, bycatch and discards of the Galapagos Marine Reserve small-scale handline fishery.

    PubMed

    Zimmerhackel, Johanna S; Schuhbauer, Anna C; Usseglio, Paolo; Heel, Lena C; Salinas-de-León, Pelayo

    2015-01-01

    Fisheries bycatch is a significant marine conservation issue as valuable fish are wasted and protected species harmed with potential negative ecological and socio-economic consequences. Even though there are indications that the small-scale handline fishery of the Galapagos Marine Reserve has a low selectivity, information on its bycatch has never been published. We used onboard monitoring and interview data to assess the bycatch of the Galapagos handline fishery by estimating the bycatch ratio, determining species compositions of landings and bycatch, identifying fishers' reasons for discarding certain individuals, and revealing historical trends in the bycatch ratio. The estimated bycatch ratio as a function of biomass of 0.40 and a diverse species composition of target catch and bycatch confirmed the low selectivity of this fishery. Most individuals were not landed for economic motivations, either because species (77.4%) or sizes (17.7%) are unmarketable or for regulatory reasons (5.9%). We found that bycatch contributes to growth overfishing of some target species because they are discarded or used as bait before reaching their first maturity. Moreover, over half of interviewees perceived a historical decrease in bycatch ratios that was explained by a diversification of the target catch due to the reduction in abundance of the traditionally most important target species. As some target species show signs of overfishing and to date there are no specific regulations for the finfish fishery species in place, we recommend the implementation of a series of management measures to protect critical life stages of overexploited species and to improve the selectivity of the Galapagos handline fishery. PMID:26082874

  19. Differences in insect resistance between tomato species endemic to the Galapagos Islands

    PubMed Central

    2013-01-01

    Background The Galapagos Islands constitute a highly diverse ecosystem and a unique source of variation in the form of endemic species. There are two endemic tomato species, Solanum galapagense and S. cheesmaniae and two introduced tomato species, S. pimpinellifolium and S. lycopersicum. Morphologically the two endemic tomato species of the Galapagos Islands are clearly distinct, but molecular marker analysis showed no clear separation. Tomatoes on the Galapagos are affected by both native and exotic herbivores. Bemisia tabaci is an important introduced insect species that feeds on a wide range of plants. In this article, we address the question whether the differentiation between S. galapagense and S. cheesmaniae may be related to differences in susceptibility towards phloem-feeders and used B. tabaci as a model to evaluate this. Results We have characterized 12 accessions of S. galapagense, 22 of S. cheesmaniae, and one of S. lycopersicum as reference for whitefly resistance using no-choice experiments. Whitefly resistance was found in S. galapagense only and was associated with the presence of relatively high levels of acyl sugars and the presence of glandular trichomes of type I and IV. Genetic fingerprinting using 3316 SNP markers did not show a clear differentiation between the two endemic species. Acyl sugar accumulation as well as the climatic and geographical conditions at the collection sites of the accessions did not follow the morphological species boundaries. Conclusion Our results suggest that S. galapagense and S. cheesmaniae might be morphotypes rather than two species and that their co-existence is likely the result of selective pressure. PMID:23972016

  20. Zoanthid diversity (Anthozoa: Hexacorallia) in the Galapagos Islands: a molecular examination

    NASA Astrophysics Data System (ADS)

    Reimer, J. D.; Sinniger, F.; Hickman, C. P.

    2008-09-01

    Although the Galapagos are famous for their unique biodiversity, many groups of marine invertebrates from this isolated archipelago remain understudied or not investigated. One such group is the zoanthids (Order Zoantharia, =Zoanthidea, =Zoanthiniaria), anthozoans (Cnidaria) found in marine ecosystems worldwide. Zoanthid taxonomy has been in a state of disorganization and neglect due in large part to the morphological plasticity within species and questions about the accuracy of traditionally used morphological and ecological characteristics. However, recent studies utilizing molecular methodology combined with morphology have proven to be very useful in understanding zoanthid diversity. The results of a survey of zoanthids from the Galapagos and the east Pacific are reported in this study. Shallow water (<35 m) zoanthid specimens were identified using the molecular markers mitochondrial 16S ribosomal DNA (mt 16S rDNA), cytochrome oxidase subunit I (COI) gene, and the internal transcribed spacer of ribosomal DNA (ITS-rDNA). From the collected specimens seven putative zoanthid species-level clades from three known genera ( Zoanthus, Palythoa, Parazoanthus) were identified at the molecular level. These identifications were further supported by morphological and ecological data. While almost all specimens belonged to known zoanthid genera, based on unique molecular and ecological data one group of specimens (designated unknown zoanthid sp. “03-103”) is potentially a novel undescribed genus. Additionally, the remaining three azooxanthellate Parazoanthus clades may also be undescribed new species, but due to the overall lack of zoanthid research and descriptions from neighboring areas (East Pacific, west coast of South America) further research is needed to clearly ascertain this. Additionally, notes on the four observed nominal azooxanthellate zoanthid species and a key to all eight nominal (seven from known genera, one from a potentially new genus) shallow water

  1. Catch, bycatch and discards of the Galapagos Marine Reserve small-scale handline fishery.

    PubMed

    Zimmerhackel, Johanna S; Schuhbauer, Anna C; Usseglio, Paolo; Heel, Lena C; Salinas-de-León, Pelayo

    2015-01-01

    Fisheries bycatch is a significant marine conservation issue as valuable fish are wasted and protected species harmed with potential negative ecological and socio-economic consequences. Even though there are indications that the small-scale handline fishery of the Galapagos Marine Reserve has a low selectivity, information on its bycatch has never been published. We used onboard monitoring and interview data to assess the bycatch of the Galapagos handline fishery by estimating the bycatch ratio, determining species compositions of landings and bycatch, identifying fishers' reasons for discarding certain individuals, and revealing historical trends in the bycatch ratio. The estimated bycatch ratio as a function of biomass of 0.40 and a diverse species composition of target catch and bycatch confirmed the low selectivity of this fishery. Most individuals were not landed for economic motivations, either because species (77.4%) or sizes (17.7%) are unmarketable or for regulatory reasons (5.9%). We found that bycatch contributes to growth overfishing of some target species because they are discarded or used as bait before reaching their first maturity. Moreover, over half of interviewees perceived a historical decrease in bycatch ratios that was explained by a diversification of the target catch due to the reduction in abundance of the traditionally most important target species. As some target species show signs of overfishing and to date there are no specific regulations for the finfish fishery species in place, we recommend the implementation of a series of management measures to protect critical life stages of overexploited species and to improve the selectivity of the Galapagos handline fishery.

  2. Microbial Community Structure in Hydrothermal Plumes of the Galapagos Spreading Center

    NASA Astrophysics Data System (ADS)

    Heintz, M. B.; Haymon, R.; Valentine, D. L.; Carlson, C.; Resing, J.; Baker, E.; Lebon, G.; Walker, S.; Ehrhardt, C.; Swan, B.

    2006-12-01

    Prior studies indicate that prokaryotes affect the chemical evolution of deep-sea hydrothermal plumes and nourish higher trophic levels in and above plumes. A few studies of microbial community composition within hydrothermal plumes have been undertaken, but it is unknown how plume microbial community structure varies geographically, or how it relates to chemical composition of plumes. To investigate microbial diversity in plumes, we collected a suite of 60 filtered water samples along a 300 nautical-mile section of the Galapagos Spreading Center during the 2005-06 GalAPAGoS Expedition. Samples were collected within and outside of plumes from both high and low temperature hydrothermal environments at varying stages of maturity. These samples were collected in parallel with measurements and samples taken for physical and chemical characterization of plumes. Initial work with the microbial samples focuses on characterizing community fingerprints from terminal restriction fragment length polymorphism (T-RFLP) analysis of the 16S rRNA gene amplified from both Bacteria and Archaea. Preliminary investigation of a vertical cast through a plume in the Iguanas Vent Field (located at lat./long. 2.10428/-91.9356) suggest there are distinct microbial groups that exist throughout the vertical profile, other groups that are only present within the plume, and certain groups that are only found outside of the plume. Preliminary results also suggest that there are changes in overall diversity patterns within and outside of the plume. Further work is in progress to verify and expand on these initial results. This suite of Galapagos samples promises new insights into biogeochemical cycles of vent- influenced areas of the deep-sea.

  3. The Temporal Scale of Holocene Climatic Variability: From the Galapagos to Amazonia

    NASA Astrophysics Data System (ADS)

    Bush, M. B.; Restrepo, A.; Correa, A.; Ford, R.; Valencia, B.; Gosling, W.; Silman, M.; Conroy, J.; Overpeck, J. T.

    2006-12-01

    High-resolution lake cores from the Andes and Amazonian lowlands of W. South America and the Galapagos Islands provide new insights into the Holocene climate history of this region and its interactions with Pacific climate drivers. Our data reveal that a major drought event reported broadly from the Andes and Amazonia in the early to mid-Holocene is actually a complex series of droughts with wet interludes. These results suggest strong climatic instability prior to c. 5600 cal. yr BP. Establishment of wetter conditions at our Andean study site at c. 5600 cal. yr BP correspond to the start of Quinoa cultivation. A similar pattern of higher lake levels coinciding with the local spread of agriculture is also evident in the lowlands. Within an overall pattern of progressively wetter conditions over the last 4000 years there are periods of pronounced climatic instability (drought and flood). Fossil pollen, charcoal, sediment color, and carbon content identify periods of peak erosion between c. 900 and 1100 cal. yr BP. On the Galapagos Islands, a subdecadally resolved analysis of fossil pollen provides a striking pattern of climatic change and human-induced alteration of the landscape. Prior to the period of transforming human activity, the fossil pollen record contains a multidecadal oscillation, with wavlet analysis evealing a quasi- periodicty of c. 60 years. Andean pollen are readily identifible in the Galapagos record and transport of mainland pollen to the islands has varied markedly within the past millennium. These multiproxy records reveal the dynamic nature of Holocene climates in the tropics and the impact those changes have had on people and landscapes.

  4. Catch, bycatch and discards of the Galapagos Marine Reserve small-scale handline fishery

    PubMed Central

    Schuhbauer, Anna C.; Usseglio, Paolo; Heel, Lena C.; Salinas-de-León, Pelayo

    2015-01-01

    Fisheries bycatch is a significant marine conservation issue as valuable fish are wasted and protected species harmed with potential negative ecological and socio-economic consequences. Even though there are indications that the small-scale handline fishery of the Galapagos Marine Reserve has a low selectivity, information on its bycatch has never been published. We used onboard monitoring and interview data to assess the bycatch of the Galapagos handline fishery by estimating the bycatch ratio, determining species compositions of landings and bycatch, identifying fishers’ reasons for discarding certain individuals, and revealing historical trends in the bycatch ratio. The estimated bycatch ratio as a function of biomass of 0.40 and a diverse species composition of target catch and bycatch confirmed the low selectivity of this fishery. Most individuals were not landed for economic motivations, either because species (77.4%) or sizes (17.7%) are unmarketable or for regulatory reasons (5.9%). We found that bycatch contributes to growth overfishing of some target species because they are discarded or used as bait before reaching their first maturity. Moreover, over half of interviewees perceived a historical decrease in bycatch ratios that was explained by a diversification of the target catch due to the reduction in abundance of the traditionally most important target species. As some target species show signs of overfishing and to date there are no specific regulations for the finfish fishery species in place, we recommend the implementation of a series of management measures to protect critical life stages of overexploited species and to improve the selectivity of the Galapagos handline fishery. PMID:26082874

  5. Volcanic Evolution in the Galapagos: The Geochemistry and Petrology of Espanola Island

    NASA Astrophysics Data System (ADS)

    McGuire, M.; Varga, K. C.; Harpp, K. S.; Geist, D.; Hall, M. L.

    2015-12-01

    The Galapagos Archipelago consists of a series of volcanic islands located ~1,000 km west of South America that are thought to be the result of a mantle plume. The southeasternmost island, Espanola, is one of the smallest of the major islands, measuring only 7 by 14 km and reaching an elevation of 200 m. Espanola is also the oldest island in the chain, with K-Ar dates from 3.01 ± 0.11 to 3.31 ± 0.36 million years (Hall et al. 1983; White et al., 1993). The southern coast is defined by cliffs that exceed 100 m in height, made up of nearly flat-lying lavas that are each several meters thick. The northern coastline consists of lavas that dip gently toward the ocean from the highlands, as well as remnants of eroded cinder cones. Paleomagnetic measurements made in the field indicate that the western half of the island is reversely polarized, whereas most lavas measured across the eastern half are normally polarized. Major element analyses of samples from across the island indicate that fractional crystallization is the dominant process controlling chemical variations in Espanola lavas, suggesting a relatively long-lived magmatic plumbing system. Stratigraphically constrained chemical variations suggest the magma chamber may have experienced periodic replenishment by compositionally homogeneous primitive melts. Variable fluid-mobile trace element concentrations provide some evidence for contributions from ancient, recycled oceanic crust to the parental melts. Espanola lavas have more depleted Sr and Pb radiogenic isotope ratios than either Floreana or Fernandina, and lie on a mixing curve between the composition of the plume and that of the depleted upper mantle. Between ~3 and 8 Ma, the Galapagos Spreading Center was closer to the Galapagos plume than it is today. Given that Espanola was constructed during the same period, the depleted isotopic signatures suggest that plume-ridge interaction may have been a strong influence on the island's geochemical composition.

  6. The Role of Plume-Ridge Interaction in Magma Genesis III: Darwin Island, Galapagos

    NASA Astrophysics Data System (ADS)

    Reed, L. A.; Harpp, K. S.; Blair, S. W.; Koleszar, A. M.

    2002-12-01

    Located only 50 km south of the Galapagos Spreading Center, Darwin Island marks the northernmost extension of the Wolf-Darwin Lineament, a >50 km-long alignment of volcanoes and seamounts north of the main Galapagos Archipelago. Like neighboring Wolf Island, Darwin formed closer to the GSC than to the plume center and sits on younger lithosphere than the rest of the Galapagos volcanoes. A small (1.5 km2), largely inaccessible island, Darwin has experienced at least two explosive episodes during its history. The base consists of a ~20 m-thick tuff layer covered by over 40 meters of predominantly plagioclase ultraphyric basalt flows. The lavas are generally of uniform thickness (1-2 m), but can reach up to 8 m near the top of the sequence. A second tuff layer caps the lava flows, evidence of a later explosive phase. Although sub-aerially Darwin appears to be volumetrically insignificant, bathymetric and field evidence suggest that what is currently visible is merely the eroded remnant of a much larger volcano with an elongate footprint parallel to the WDL. Morphological evidence indicates that Darwin is significantly younger than Wolf Island, which is confirmed by previous age determinations (White et al., 1993). Darwin lava flows are compositionally homogeneous, in stark contrast to the wide variation observed at Wolf Island, possibly the result of Darwin's younger age. Darwin lavas exhibit moderately enriched signatures similar to those erupted along the adjacent GSC, indication that the Galapagos plume is a significant component of Darwin's mantle source. The wide range and erratic distribution of compositions along the WDL further suggest each volcano is tapping mantle that is a spatially variable mixture of depleted and plume material, rather than a sub-lithospheric pipeline transporting plume material to the ridge. We propose that Darwin, along with the rest of the WDL, is the surface manifestation of tensional volcanism induced by ridge-transform stresses

  7. The Role of Plume-Ridge Interaction in Magma Genesis I: The Northern Galapagos

    NASA Astrophysics Data System (ADS)

    Harpp, K. S.; Geist, D. J.

    2002-12-01

    A group of enigmatic volcanoes populates the ocean floor between the hotspot and the Galapagos Spreading Center (GSC), including many seamounts, a few isolated islands (Pinta, Marchena, and Genovesa), and the Wolf-Darwin Lineament (WDL). The WDL is a NW trending bathymetric high between the Galapagos platform and the GSC. Many of the northern Galapagos volcanoes are unusually elongate edifices that trend parallel to the strike of their local lineament. The seafloor between Pinta and Marchena is cut by fractures and fissures parallel to the WDL, and a major submarine ridge extends NE from fissures that cross-cut Genovesa Island. Elongate volcanic structures are unusual in off-axis seamount provinces and indicate strong deviatoric stresses on a regional scale. Individual volcanoes in the northern Galapagos generally exhibit homogeneous geochemical signatures, although this may be an artifact of sparse sampling (see Blair et al. abstract). Regionally, however, lavas range from plume-like enrichment (Pinta) to MORB-like depletion (Genovesa, S. WDL), with many volcanoes of intermediate composition (Darwin, Marchena). The WDL volcanoes define two distinct chemical groups; lavas erupted south of Wolf Island are similar to those from the GSC west of 93°W, while the northern WDL resembles lavas from the GSC segment directly to their north. This distribution implies that the WDL is supplied by the same type of plume-affected mantle as the GSC segment that produced the lithosphere underlying the volcanoes. We propose that the WDL and perhaps other northern volcanoes are primarily the result of tensional stresses emanating from the inside corner of the GSC transform fault at 91°W. The oblique orientation of the fault with respect to the Nazca plate spreading direction may further enhance regional tensional forces. The area is magmatic owing to the overlapping effects of the ridge and the plume. The volcanoes simply tap hybrid products of mixing at the margins of the sub

  8. Giant Galapagos tortoises walk without inverted pendulum mechanical-energy exchange.

    PubMed

    Zani, Peter A; Gottschall, Jinger S; Kram, Rodger

    2005-04-01

    Animals must perform mechanical work during walking, but most conserve substantial mechanical energy via an inverted-pendulum-like mechanism of energy recovery in which fluctuations of kinetic energy (KE) and gravitational potential energy (GPE) are of similar magnitude and 180 degrees out of phase. The greatest energy recovery typically occurs at intermediate speeds. Tortoises are known for their slow speeds, which we anticipated would lead to small fluctuations in KE. To have an effective exchange of mechanical energy using the inverted-pendulum mechanism, tortoises would need to walk with only small changes in GPE corresponding to vertical center-of-mass (COM) fluctuations of < 0.5 mm. Thus, we hypothesized that giant Galapagos tortoises would not conserve substantial mechanical energy using the inverted-pendulum mechanism. We studied five adult giant Galapagos tortoises Geochelone elephantopus (mean mass=142 kg; range= 103-196 kg). Walking speed was extremely slow (0.16+/-0.052 m s(-1); mean +/- 1 s.d.). The fluctuations in kinetic energy (8.1+/-3.98 J stride(-1)) were only one-third as large as the fluctuations in gravitational potential energy (22.7+/-8.04 J stride(-1)). In addition, these energies fluctuated nearly randomly and were only sporadically out of phase. Because of the dissimilar amplitudes and inconsistent phase relationships of these energies, tortoises conserved little mechanical energy during steady walking, recovering only 29.8+/-3.77% of the mechanical energy (range=13-52%). Thus, giant Galapagos tortoises do not utilize effectively an inverted-pendulum mechanism of energy conservation. Nonetheless, the mass-specific external mechanical work required per distance (0.41+/-0.092 J kg(-1) m(-1)) was not different from most other legged animals. Other turtle species use less than half as much metabolic energy to walk as other terrestrial animals of similar mass. It is not yet known if Galapagos tortoises are economical walkers. Nevertheless

  9. Intra-annual variability of the radiocarbon content of corals from the Galapagos Islands

    SciTech Connect

    Brown, T.A. Geophysics Program AK-50, Univ. of Washington, Seattle, WA ); Farwell, G.W.; Schmidt, F.H. ); Grootes, P.M. Quatenary Isotope Lab. AK-60, Dept. of Geological Sciences, Univ. of Washington, Seattle, WA ); Stuiver, M. )

    1993-01-01

    The authors report AMS [sup 14]C measurements on sub annual samples of coral from the Galapagos Islands that span the period, 1970-1973. Both the major 1972 El Nino/Southern Oscillation event and intra-annual changes in regional upwelling of [sup 14]C-depleted waters associated with alternation of surface-ocean current patterns are evident in the record. These data show that the corals preserve a detailed record of past intra-annual variations of the [sup 14]C content of surface ocean water.

  10. Examination of the constructional processes of submarine Cerro Azul and the Galapagos Platform

    NASA Astrophysics Data System (ADS)

    Lambert, M. K.; Harpp, K. S.; Geist, D. J.; Fornari, D. J.; Kurz, M. D.; Koleszar, A. M.; Rollins, N. A.

    2004-05-01

    One of the primary goals of the 2001 Drift04 cruise was to examine the constructional processes responsible for the Galapagos platform and to investigate the relationship between the platform and the overlying volcanoes. Cerro Azul volcano is located above the steep escarpment that marks the southwestern limit of the Galapagos platform, at the leading edge of the hotspot. This area is of particular interest in light of a recent seismic tomography experiment by Toomey, Hooft, et al., which suggests that the root of the Galapagos plume is centered between Cerro Azul and adjacent Fernandina Island. During the Drift04 cruise, detailed bathymetric and sidescan sonar studies were carried out across the submarine sector of Cerro Azul and 14 dredges were collected from the same area. Major element analyses of the submarine lavas indicate that the lavas from the platform edge and the subaerial Cerro Azul lavas constitute a suite of petrologically-related lavas. The dredged glasses of the Drift04 cruise have MgO contents of <7.5% and are indistinguishable from published data on Cerro Azul. Whole rock analyses include a highly primitive sample (20 wt% MgO), which probably contains accumulated olivine. All the submarine and subaerial lavas define coherent trends in major element space that are consistent with variable amounts of olivine and olivine+cpx fractionation. Incompatible trace element (ITE) ratios indicate that the mantle source for the submarine platform flows is intermediate in composition between the magmas supplying Fernandina and Cerro Azul. Previous researchers have proposed that two mantle endmembers are interacting across the leading edge of the plume, one focused at Fernandina and the other at Floreana Island. The intermediate ITE ratios of the submarine and subaerial Cerro Azul lavas are consistent both geographically and compositionally with this hypothesis. Naumann and co-workers concluded that the lavas erupted at Cerro Azul were stored in small

  11. Exploring individual quality: Basal metabolic rate and reproductive performance in storm-petrels

    USGS Publications Warehouse

    Blackmer, A.L.; Mauck, R.A.; Ackerman, J.T.; Huntington, C.E.; Nevitt, G.A.; Williams, J.B.

    2005-01-01

    Despite evidence that some individuals achieve both superior reproductive performance and high survivorship, the factors underlying variation in individual quality are not well understood. The compensation and increased-intake hypotheses predict that basal metabolic rate (BMR) influences reproductive performance; if so, variation in BMR may be related to differences in individual quality. We evaluated whether BMR measured during the incubation period provides a proximate explanation for variation in individual quality by measuring the BMRs and reproductive performance of Leach's storm-petrels (Oceanodroma leucorhoa) breeding on Kent Island, New Brunswick, Canada, during 2000 and 2001. We statistically controlled for internal (body mass, breeding age, sex) and external (year, date, time of day) effects on BMR. We found that males with relatively low BMRs hatched their eggs earlier in the season and that their chicks' wing growth rates were faster compared to males with relatively high BMRs. Conversely, BMR was not related to egg volume, hatching date, or chick growth rate for females or to lifetime (???23 years) hatching success for either sex. Thus, for males but not for females, our results support the compensation hypothesis. This hypothesis predicts that animals with low BMRs will achieve better reproductive performance than animals with high BMRs because they have lower self-maintenance costs and therefore can apportion more energy to reproduction. These results provide evidence that intraspecific variation in reproductive performance is related to BMR and suggest that BMR may influence individual quality in males. ?? The Author 2005. Published by Oxford University Press on behalf of the International Society for Behavioral Ecology. All rights reserved.

  12. Lack of porphyroblast rotation in noncoaxially deformed schists from Petrel Cove, South Australia, and its implications

    NASA Astrophysics Data System (ADS)

    Steinhardt, Chris

    1989-02-01

    Inclusion trails representing an S 1 cleavage demonstrate the lack of porphyroblast rotation during subsequent highly non-coaxial deformations. The pelitic schists of the Kanmantoo Group at Petrel Cove, South Australia contain two generations of porphyroblasts. The first one consists of cordierite porphyroblasts that formed early in D 2 and contain straight to slightly sigmoidal inclusion trails of S 1. The second generation consists of andalusite porphyroblasts that overgrew crenulated S 2 late during D 3. Several hundred inclusion trail traces from cordierites measured from oriented specimens taken throughout a strongly folded area show a horizontal great circle distribution when plotted and contoured on a stereographic projection. Hence, S 1 was planar and horizontal prior to D 2. S 1 measurements on limbs and hinges of a mesoscale D 2 foldpair show that folding had little effect on porphyroblast orientation as the S 1 orientation remained constant and subhorizontal around the fold. Hence, porphyroblasts have not rotated during any of the non-coaxial deformations accompanying and following their growth. This is interpreted as a result of the partitioning of the deformation around them. S 1 in the matrix has been totally destroyed by the formation of S 2 as a fully differentiated crenulation cleavage. What has previously been regarded as inconsistent senses of shear recorded by porphyroblasts around folds is resolved by the fact that the matrix foliation rotated rather than the porphyroblasts due to the effects of deformation partitioning. The presence of a subhorizontal S 1 foliation suggests horizontal movements (e.g. thrusting or detachment faulting) during the earliest phase of the Adelaidian orogeny.

  13. Preventing Establishment: An Inventory of Introduced Plants in Puerto Villamil, Isabela Island, Galapagos

    PubMed Central

    Guézou, Anne; Pozo, Paola; Buddenhagen, Christopher

    2007-01-01

    As part of an island-wide project to identify and eradicate potentially invasive plant species before they become established, a program of inventories is being carried out in the urban and agricultural zones of the four inhabited islands in Galapagos. This study reports the results of the inventory from Puerto Villamil, a coastal village representing the urban zone of Isabela Island. We visited all 1193 village properties to record the presence of the introduced plants. In addition, information was collected from half of the properties to determine evidence for potential invasiveness of the plant species. We recorded 261 vascular taxa, 13 of which were new records for Galapagos. Most of the species were intentionally grown (cultivated) (73.3%) and used principally as ornamentals. The most frequent taxa we encountered were Cocos nucifera (coconut tree) (22.1%) as a cultivated plant and Paspalum vaginatum (salt water couch) (13.2%) as a non cultivated plant. In addition 39 taxa were naturalized. On the basis of the invasiveness study, we recommend five species for eradication (Abutilon dianthum, Datura inoxia, Datura metel, Senna alata and Solanum capsicoides), one species for hybridization studies (Opuntia ficus-indica) and three species for control (Furcraea hexapetala, Leucaena leucocephala and Paspalum vaginatum). PMID:17940606

  14. Preventing establishment: an inventory of introduced plants in Puerto Villamil, Isabela Island, Galapagos.

    PubMed

    Guézou, Anne; Pozo, Paola; Buddenhagen, Christopher

    2007-10-17

    As part of an island-wide project to identify and eradicate potentially invasive plant species before they become established, a program of inventories is being carried out in the urban and agricultural zones of the four inhabited islands in Galapagos. This study reports the results of the inventory from Puerto Villamil, a coastal village representing the urban zone of Isabela Island. We visited all 1193 village properties to record the presence of the introduced plants. In addition, information was collected from half of the properties to determine evidence for potential invasiveness of the plant species. We recorded 261 vascular taxa, 13 of which were new records for Galapagos. Most of the species were intentionally grown (cultivated) (73.3%) and used principally as ornamentals. The most frequent taxa we encountered were Cocos nucifera (coconut tree) (22.1%) as a cultivated plant and Paspalum vaginatum (salt water couch) (13.2%) as a non cultivated plant. In addition 39 taxa were naturalized. On the basis of the invasiveness study, we recommend five species for eradication (Abutilon dianthum, Datura inoxia, Datura metel, Senna alata and Solanum capsicoides), one species for hybridization studies (Opuntia ficus-indica) and three species for control (Furcraea hexapetala, Leucaena leucocephala and Paspalum vaginatum).

  15. Dog overpopulation and burden of exposure to canine distemper virus and other pathogens on Santa Cruz Island, Galapagos.

    PubMed

    Diaz, Nicole M; Mendez, Gabriella S; Grijalva, C Jaime; Walden, Heather S; Cruz, Marilyn; Aragon, Eduardo; Hernandez, Jorge A

    2016-01-01

    Dog overpopulation and diseases are hazards to native island species and humans on the Galapagos. Vaccination and importation of dogs are prohibited on the Galapagos. Risk management of these hazards requires the use of science-based risk assessment and risk communication. The objectives of the study reported here were (i) to estimate the human:dog ratio and (ii) the prevalence of and identify exposure factors associated with positive antibody titers to canine distemper virus (CDV) and other pathogens, as well as infection with intestinal parasites in owned dogs on Santa Cruz Island, Galapagos in September 2014. The observed human:dog ratio was 6.148:1 which extrapolates to 2503 dogs (two times more than a recent dog count conducted by Galapagos Biosecurity Agency in March 2014). The proportion of spayed female dogs (50%) was higher, compared to neutered male dogs (30%) (p=0.04). Prevalence of dogs with positive antibody titers to CDV was 36% (95% CI=26, 46%), to canine parvovirus was 89% (95% CI=82, 95%), and to canine adenovirus was 40% (95% CI=30, 51%). The frequency of seropositive dogs to CDV was lower in urban dogs (26%), compared to rural dogs (53%) (p<0.05). A positive interaction effect between rural residence and spay/neuter status on seropositivity to CDV was observed, which we discuss in this report. Because vaccination is prohibited, the dog population on Santa Cruz is susceptible to an outbreak of CDV (particularly among urban dogs) with potential spill over to marine mammals. Dog's age (1-2 or 3-14 years old, compared to younger dogs), and residence (rural, urban) were associated with positive antibody titers to parvovirus, adenovirus, Ehrlichia spp., or Anaplasma spp., as well as infection with Ancylostoma spp., an intestinal parasite in dogs that can be transmitted to humans, particularly children. These results provide the most comprehensive assessment of dog overpopulation and exposure to CDV and other pathogens on the Galapagos to date.

  16. Characterization of the seascape used by juvenile and wintering adult Southern Giant Petrels from Patagonia Argentina

    NASA Astrophysics Data System (ADS)

    Blanco, Gabriela S.; Pisoni, Juan P.; Quintana, Flavio

    2015-02-01

    The characterization of the seascape used by marine top predators provides a wide perspective of pelagic habitat use and it is necessary to understand the functioning of marine systems. The goal of this study was to characterize the oceanographic and biological features of marine areas used by adult and first year juvenile southern giant petrels (SGP, Macronectes giganteus) from northern Patagonian colonies (Isla Arce and Gran Robredo) during the austral fall and winter (2005, 2006, 2007, and 2008). The marine environment exploited by the SGP was characterized using sea surface temperature (SST), SST gradients, chlorophyll-a concentration, water depth, oceanographic regimes, and ocean surface winds. In addition, the biological seascape was defined by considering the distribution of squid during the months of study. Juveniles SGP exploited a wide range of environments focusing mainly on productive neritic waters using a variety of oceanographic regimes. Juveniles were exposed to eutrophic and enriched waters, probably because of the frequent presence of thermal fronts in their utilization areas. Adults' environments lacked of thermal fronts remaining the majority of their time within the oceanographic regime "Continental Shelf", in water depths of 100-200 m, exploiting mesotrophic and eutrophic environments, and remaining in areas of known food resources related to the presence of squid. For the most part, juveniles were exposed to westerly winds, which may have helped them in their initial flight to the shelf break, east of the colony. Wintering adults SGP also explored areas characterized by westerly winds but this did not play a primary role in the selection of their residence areas. Juveniles during their first year at sea have to search for food exploring a variety of unknown environments. During their search, they remained in productive environments associated to fronts and probably also associated to fisheries operating in their foraging areas. The

  17. Galapagos Plume Ridge Interaction Part 1: Morphologic Variations Along the Eastern Galapagos Spreading Center. Results From the SO158 MEGAPRINT Expedition

    NASA Astrophysics Data System (ADS)

    Hauff, F.; Christie, D. C.; Wintersteller, P.; Werner, R.; Hanan, B. B.; Hoernle, K.

    2001-12-01

    During the MEGAPRINT expedition (R/V Sonne Cruise SO158), we mapped and sampled the eastern Galapagos spreading center (GSC) between 85\\deg and 92.5\\deg W using the newly installed SIMRAD EM120 multibeam echosounder. The new maps reveal a wide range of axial morphologies, ranging through several axial valley types, some with pronounced graben structures, to both narrow and broad axial highs. The GSC shoals from 2700 meters at 86\\deg W to as little as 1500 meters in the 89\\deg - 90\\deg W area, where it lies closest to the Galapagos platform. The eastern GSC encompasses the known range of morphologies for intermediate spreading ridges with frequent transitions presumably reflecting local variations in melt supply and eruption frequency. Periods in which spreading exceeds extrusive construction are characterized by axial valleys and, in one case by a rifted axial volcano at 87\\deg W. The 91\\deg W transform fault is marked by a 3500m deep pull-apart basin containing two small recently active volcanic cones. The western GSC between 90\\deg and 92.5\\deg W is characterized by two broad axial highs separated by axial lows (see also Sinton et al. 2000). The axial highs are connected with southeastward trending chains of seamounts and small ridges, sub-parallel to the larger Wolf Darwin lineament (WDL), commonly thought to reflect today's primary plume ridge connection. The junction of the WDL and the GSC is, however, an axial low suggesting that the maximum geochemical influence of the plume (e.g., Verma and Schilling 1982), may not correlate with the WDL. Seamounts in the region between the WDL and the 91\\deg W transform are shallow and several display morphologic terraces. Dredge samples from several include rounded cobbles and nearshore sediment (beach deposits) suggesting that these seamounts may represent submerged ocean islands. It is yet not clear whether these are on-axis volcanoes or if they may have formed on older crust anologous to some of the seamounts

  18. Petrology and Geochemistry of the Northeast Seamounts of the Galapagos Platform

    NASA Astrophysics Data System (ADS)

    Sinton, C. W.; Harpp, K. S.; Christie, D. M.

    2010-12-01

    One of the best locations to study hotspot-ridge interactions is the Northern Galápagos Province (NGP), the region that lies between the Galapagos Spreading Center (GSC) and the central portion of the Galapagos Archipelago. The Galapagos hotspot is currently located off-axis from the GSC but still has a profound influence on the ridge in terms of axial lava composition and ridge bathymetry. The NGP is characterized by an array of volcanic lineaments that are composed of seamounts and five small islands. The eastern edge of the NGP is defined by a group of at least five seamounts (the Northeast Seamounts), three of which were mapped and dredged in 1990 during Leg 2 of the PLUME expedition of the R/V Thomas Washington. We report petrological and geochemical data from the basalts recovered at six dredge sites. All basalts are tholeiitic with a general MORB-like composition, but with considerable variation within some individual dredge hauls and between seamounts. Previously published isotopic data are limited but 3He/4He ratios (Graham et al. 1993) and Sr-Nd-Pb isotopic data (Harpp and White 2000) are consistent with a depleted mantle source for all three seamounts. Based on geochemistry and petrological observations, the basalts can be divided into at least thirteen distinct groups. The bulk of the analyzed glass samples have compositions more than MORB with MgO content of 8-10% wt., although two of the groups are in the 6-7% range. In addition, the primitive lavas have high CaO and Al2O3 . The mineralogy ranges from aphyric for the more evolved lavas to olivine + plagioclase-phyric or plagioclase ultraphyric for the more primitive basalts. The plagioclase appear to be very calcic (up to An91) xenocrysts that are often hosting aluminous spinel (Al2O3 46-48% wt.) and primitive melt inclusions (Sinton et al., 1993). Initial trace element data show light rare earth (LREE)-depleted signatures, although several samples are slightly enriched in the LREE. Taken together

  19. Vegetation dynamics drive segregation by body size in Galapagos tortoises migrating across altitudinal gradients.

    PubMed

    Blake, Stephen; Yackulic, Charles B; Cabrera, Fredy; Tapia, Washington; Gibbs, James P; Kümmeth, Franz; Wikelski, Martin

    2013-03-01

    Seasonal migration has evolved in many taxa as a response to predictable spatial and temporal variation in the environment. Individual traits, physiology and social state interact with environmental factors to increase the complexity of migratory systems. Despite a huge body of research, the ultimate causes of migration remain unclear. A relatively simple, tractable system - giant tortoises on Santa Cruz Island, Galapagos, was studied to elucidate the roles of environmental variation and individual traits in a partial migratory system. Specifically, we asked: (i) do Galapagos tortoises undergo long-distance seasonal migrations? (ii) is tortoise migration ultimately driven by gradients in forage quality or temperature; and (iii) how do sex and body size influence migration patterns? We recorded the daily locations of 17 GPS-tagged tortoises and walked a monthly survey along the altitudinal gradient to characterize the movements and distribution of tortoises of different sizes and sexes. Monthly temperature and rainfall data were obtained from weather stations deployed at various altitudes, and the Normalized Difference Vegetation Index was used as a proxy for forage quality. Analyses using net displacement or daily movement characteristics did not agree on assigning individuals as either migratory or non-migratory; however, both methods suggested that some individuals were migratory. Adult tortoises of both sexes move up and down an altitudinal gradient in response to changes in vegetation dynamics, not temperature. The largest tagged individuals all moved, whereas only some mid-sized individuals moved, and the smallest individuals never left lowland areas. The timing of movements varied with body size: large individuals moved upward (as lowland forage quality declined) earlier in the year than did mid-sized individuals, while the timing of downward movements was unrelated to body size and occurred as lowland vegetation productivity peaked. Giant tortoises are

  20. Vegetation dynamics drive segregation by body size in Galapagos tortoises migrating across altitudinal gradients.

    PubMed

    Blake, Stephen; Yackulic, Charles B; Cabrera, Fredy; Tapia, Washington; Gibbs, James P; Kümmeth, Franz; Wikelski, Martin

    2013-03-01

    Seasonal migration has evolved in many taxa as a response to predictable spatial and temporal variation in the environment. Individual traits, physiology and social state interact with environmental factors to increase the complexity of migratory systems. Despite a huge body of research, the ultimate causes of migration remain unclear. A relatively simple, tractable system - giant tortoises on Santa Cruz Island, Galapagos, was studied to elucidate the roles of environmental variation and individual traits in a partial migratory system. Specifically, we asked: (i) do Galapagos tortoises undergo long-distance seasonal migrations? (ii) is tortoise migration ultimately driven by gradients in forage quality or temperature; and (iii) how do sex and body size influence migration patterns? We recorded the daily locations of 17 GPS-tagged tortoises and walked a monthly survey along the altitudinal gradient to characterize the movements and distribution of tortoises of different sizes and sexes. Monthly temperature and rainfall data were obtained from weather stations deployed at various altitudes, and the Normalized Difference Vegetation Index was used as a proxy for forage quality. Analyses using net displacement or daily movement characteristics did not agree on assigning individuals as either migratory or non-migratory; however, both methods suggested that some individuals were migratory. Adult tortoises of both sexes move up and down an altitudinal gradient in response to changes in vegetation dynamics, not temperature. The largest tagged individuals all moved, whereas only some mid-sized individuals moved, and the smallest individuals never left lowland areas. The timing of movements varied with body size: large individuals moved upward (as lowland forage quality declined) earlier in the year than did mid-sized individuals, while the timing of downward movements was unrelated to body size and occurred as lowland vegetation productivity peaked. Giant tortoises are

  1. Persistent organic pollutants in blood samples of Southern Giant Petrels (Macronectes giganteus) from the South Shetland Islands, Antarctica.

    PubMed

    Colabuono, Fernanda I; Vander Pol, Stacy S; Huncik, Kevin M; Taniguchi, Satie; Petry, Maria V; Kucklick, John R; Montone, Rosalinda C

    2016-09-01

    Seabirds play an important role as top consumers in the food web and can be used as biomonitors of exposure to pollutants. Contamination studies involving non-destructive sampling methods are of considerable importance, allowing better evaluation of the levels of pollutants and their toxic effects. In the present study, organohalogen contaminants were analyzed in 113 blood samples from Southern Giant Petrel (Macronectes giganteus) adults and chicks collected in the austral summer of 2011/2012 and 2012/2013 from colonies on Elephant and Livingston Islands, South Shetland, Antarctica. Polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), pentachlorobenzene (PeCB), mirex, dichlorodiphenyltrichloroetane and derivatives (DDTs) and chlordanes were detected in all birds, whereas polybrominated diphenyl ethers (PBDEs) were not detected in any blood samples. No significant differences were found in organochlorine levels between sampling events. Adults exhibited significantly higher levels than chicks, except for PeCB. PCBs, HCB, mirex and DDTs were statistically similar in males and females from Elephant Island. Females on Livingston Island exhibited higher HCB values than males, but no sex differences were found regarding other organochlorines. The similarity in organochlorine levels between sexes in birds with very marked sexual segregation in feeding habits during the breeding season may indicate that significant amounts of contaminants are acquired during migration to lower latitudes, when the diets of males and females are similar. Birds sampled on Livingston Island exhibited significantly lower levels of PCBs, HCB, DDTs, mirex and chlordanes in comparison to those on Elephant Island, which could be the result of distinct foraging patterns between the two colonies. Organochlorine levels were similar between years in birds captured in two consecutive breeding seasons. Blood samples from Southern Giant Petrels adults and chicks proved to be useful for the comparison

  2. Comparative ectoparasite loads of five seabird species in the Galapagos Islands.

    PubMed

    Rivera-Parra, Jose L; Levin, Iris I; Parker, Patricia G

    2014-10-01

    In this paper we describe the ectoparasitic lice (Insecta: Phthiraptera) found on 5 species of seabirds (magnificent frigatebird Fregata magnificens; great frigatebird Fregata minor ; Nazca booby Sula granti ; blue-footed booby Sula nebouxii ; and red-footed booby Sula sula ) on the Galapagos Archipelago. We found 9 species of ectoparasitic lice: 5 species of Pectinopygus ischnocerans, 1 infesting each host; 2 species of Colpocephalum amblyceran lice, 1 on each frigatebird species; and 2 shared amblycerans, Eidmanniella albescens (Piaget, 1880) found on Nazca and blue-footed boobies and Fregatiella aurifasciata (Kellogg, 1899) found on the 2 frigatebirds. We tested the relative importance and interactions of host sex, body size, host, island, host family, and breeding status and found that inter-island differences were the main predictors of prevalence and infestation intensity. These differences could be related to host density or weather, but further evidence is needed. PMID:24911632

  3. Comparative ectoparasite loads of five seabird species in the Galapagos Islands.

    PubMed

    Rivera-Parra, Jose L; Levin, Iris I; Parker, Patricia G

    2014-10-01

    In this paper we describe the ectoparasitic lice (Insecta: Phthiraptera) found on 5 species of seabirds (magnificent frigatebird Fregata magnificens; great frigatebird Fregata minor ; Nazca booby Sula granti ; blue-footed booby Sula nebouxii ; and red-footed booby Sula sula ) on the Galapagos Archipelago. We found 9 species of ectoparasitic lice: 5 species of Pectinopygus ischnocerans, 1 infesting each host; 2 species of Colpocephalum amblyceran lice, 1 on each frigatebird species; and 2 shared amblycerans, Eidmanniella albescens (Piaget, 1880) found on Nazca and blue-footed boobies and Fregatiella aurifasciata (Kellogg, 1899) found on the 2 frigatebirds. We tested the relative importance and interactions of host sex, body size, host, island, host family, and breeding status and found that inter-island differences were the main predictors of prevalence and infestation intensity. These differences could be related to host density or weather, but further evidence is needed.

  4. PET2OGS: Algorithms to link the static model of Petrel with the dynamic model of OpenGeoSys

    NASA Astrophysics Data System (ADS)

    Park, C.-H.; Shinn, Y. J.; Park, Y.-C.; Huh, D.-G.; Lee, S. K.

    2014-01-01

    A set of three algorithms named PET2OGS is developed to integrate the static model (Petrel) with the dynamic model (OpenGeoSys). PET2OGS consists of three sub-algorithms that convert finite difference methods (FDMs) grids to finite element methods (FEMs) grids. The algorithms and the workflow of the integration procedures are described in detail. After the proposed algorithms are tested on a variety of grids both in homogeneous and heterogeneous media, the integrated platform of the static and dynamic models is applied to model CO2 storage in a saline aquifer. A successful demonstration of the proposed algorithms proved a robust integration of the platform. With some minor modifications of the algorithms in the part of input and output, the proposed algorithms can be extended to integrate different combinations of FDM-based static models and FEM-based dynamic models beyond the example combination in the paper.

  5. Trace metals in contemporary and seventeenth-century Galapagos coral: Records of seasonal and annual variations

    SciTech Connect

    Linn, L.J.; Delaney, M.L.; Druffel, E.R.M. )

    1990-02-01

    The authors report trace element/calcium ratios for modern (Cu/Ca, Mn/Ca, Cd/Ca and Pb/Ca) and seventeenth-century (Cu/Ca, Mn/Ca, and Pb/Ca) specimens of Pavona clavus collected in the Galapagos Islands. These data include the first reliable measurements of Cu/Ca ratios in coralline aragonite. They estimate that the ratio of Cu/Ca in the lattice to that in seawater (i.e., the effective distribution coefficient) is {approx} 0.3, lower than the value of 1 observed for several other divalent elements; they estimate the effective distribution coefficient for Mn is {approx} 1. Distribution coefficients in coral aragonite for 8 divalent metals are near unity despite different ionic radii and chemical speciation in seawater. In a modern Hood Island coral, quarter-annually sampled from 1964-73, Cu/Ca ratios decrease twofold from the late 1960s to early 1970s. Mn/Ca and Cd/Ca ratios vary seasonally with upwelling and the generic El Nino. The El Nino Southern Oscillation (ENSO) events of 1965, 1969, and 1972 are marked by suppression of Cd/Ca ratios by about 2.5 nmol/mol, while the Mn/Ca ratio is highest during the strong 1972 ENSO. Pb/Ca ratios were relatively constant throughout this period. From the Cu/Ca record of a seventeenth-century Urvina Bay coral annually sampled from 1600-1725 and the estimated Cu distribution coefficient, surface seawater Cu concentrations at Galapagos during the seventeenth century were similar to present day at 0.7-1.4 nmol/kg. Estimated Pb concentrations were lower at 5-20 pmol/kg, and Mn concentrations were slightly higher at 1.6-2.8 nmol/kg.

  6. Hydrothermal alteration in oceanic ridge volcanics: A detailed study at the Galapagos Fossil Hydrothermal Field

    USGS Publications Warehouse

    Ridley, W.I.; Perfit, M.R.; Josnasson, I.R.; Smith, M.F.

    1994-01-01

    The Galapagos Fossil Hydrothermal Field is composed of altered oceanic crust and extinct hydrothermal vents within the eastern Galapagos Rift between 85??49???W and 85??55???W. The discharge zone of the hydrothermal system is revealed along scarps, thus providing an opportunity to examine the uppermost mineralized, and highly altered interior parts of the crust. Altered rocks collected in situ by the submersible ALVIN show complex concentric alteration zones. Microsamples of individual zones have been analysed for major/minor, trace elements, and strontium isotopes in order to describe the complex compositional details of the hydrothermal alteration. Interlayered chlorite-smectite and chlorite with disequilibrium compositions dominate the secondary mineralogy as replacement phases of primary glass and acicular pyroxene. Phenocrysts and matrix grains of plagioclase are unaffected during alteration. Using a modification of the Gresens' equation we demonstrate that the trivalent rare earth elements (REEs) are relatively immobile, and calculate degrees of enrichment and depletion in other elements. Strontium isotopic ratios increase as Sr concentrations decrease from least-altered cores to most-altered rims and cross-cutting veins in individual samples, and can be modeled by open system behaviour under low fluid-rock ratio (< 10) conditions following a period of lower-temperature weathering of volcanics within the rift zone. The complex patterns of element enrichment and depletion and strontium isotope variations indicate mixing between pristine seawater and ascending hot fluids to produce a compositional spectrum of fluids. The precipitation of base-metal sulfides beneath the seafloor is probably a result of fluid mixing and cooling. If, as suggested here, the discharge zone alteration occurred under relatively low fluid-rock ratios, then this shallow region must play an important role in determining the exit composition of vent fluids in marine hydrothermal systems

  7. Blood gases, biochemistry, and hematology of Galapagos green turtles (Chelonia mydas).

    PubMed

    Lewbart, Gregory A; Hirschfeld, Maximilian; Denkinger, Judith; Vasco, Karla; Guevara, Nataly; García, Juan; Muñoz, Juanpablo; Lohmann, Kenneth J

    2014-01-01

    The green turtle, Chelonia mydas, is an endangered marine chelonian with a circum-global distribution. Reference blood parameter intervals have been published for some chelonian species, but baseline hematology, biochemical, and blood gas values are lacking from the Galapagos sea turtles. Analyses were done on blood samples drawn from 28 green turtles captured in two foraging locations on San Cristóbal Island (14 from each site). Of these turtles, 20 were immature and of unknown sex; the other eight were males (five mature, three immature). A portable blood analyzer (iSTAT) was used to obtain near immediate field results for pH, lactate, pO2, pCO2, HCO3-, Hct, Hb, Na, K, iCa, and Glu. Parameter values affected by temperature were corrected in two ways: (1) with standard formulas; and (2) with auto-corrections made by the iSTAT. The two methods yielded clinically equivalent results. Standard laboratory hematology techniques were employed for the red and white blood cell counts and the hematocrit determination, which was also compared to the hematocrit values generated by the iSTAT. Of all blood analytes, only lactate concentrations were positively correlated with body size. All other values showed no significant difference between the two sample locations nor were they correlated with body size or internal temperature. For hematocrit count, the iSTAT blood analyzer yielded results indistinguishable from those obtained with high-speed centrifugation. The values reported in this study provide baseline data that may be useful in comparisons among populations and in detecting changes in health status among Galapagos sea turtles. The findings might also be helpful in future efforts to demonstrate associations between specific biochemical parameters and disease.

  8. Blood Gases, Biochemistry, and Hematology of Galapagos Green Turtles (Chelonia Mydas)

    PubMed Central

    Lewbart, Gregory A.; Hirschfeld, Maximilian; Denkinger, Judith; Vasco, Karla; Guevara, Nataly; García, Juan; Muñoz, Juanpablo; Lohmann, Kenneth J.

    2014-01-01

    The green turtle, Chelonia mydas, is an endangered marine chelonian with a circum-global distribution. Reference blood parameter intervals have been published for some chelonian species, but baseline hematology, biochemical, and blood gas values are lacking from the Galapagos sea turtles. Analyses were done on blood samples drawn from 28 green turtles captured in two foraging locations on San Cristóbal Island (14 from each site). Of these turtles, 20 were immature and of unknown sex; the other eight were males (five mature, three immature). A portable blood analyzer (iSTAT) was used to obtain near immediate field results for pH, lactate, pO2, pCO2, HCO3−, Hct, Hb, Na, K, iCa, and Glu. Parameter values affected by temperature were corrected in two ways: (1) with standard formulas; and (2) with auto-corrections made by the iSTAT. The two methods yielded clinically equivalent results. Standard laboratory hematology techniques were employed for the red and white blood cell counts and the hematocrit determination, which was also compared to the hematocrit values generated by the iSTAT. Of all blood analytes, only lactate concentrations were positively correlated with body size. All other values showed no significant difference between the two sample locations nor were they correlated with body size or internal temperature. For hematocrit count, the iSTAT blood analyzer yielded results indistinguishable from those obtained with high-speed centrifugation. The values reported in this study provide baseline data that may be useful in comparisons among populations and in detecting changes in health status among Galapagos sea turtles. The findings might also be helpful in future efforts to demonstrate associations between specific biochemical parameters and disease. PMID:24824065

  9. Blood gases, biochemistry, and hematology of Galapagos green turtles (Chelonia mydas).

    PubMed

    Lewbart, Gregory A; Hirschfeld, Maximilian; Denkinger, Judith; Vasco, Karla; Guevara, Nataly; García, Juan; Muñoz, Juanpablo; Lohmann, Kenneth J

    2014-01-01

    The green turtle, Chelonia mydas, is an endangered marine chelonian with a circum-global distribution. Reference blood parameter intervals have been published for some chelonian species, but baseline hematology, biochemical, and blood gas values are lacking from the Galapagos sea turtles. Analyses were done on blood samples drawn from 28 green turtles captured in two foraging locations on San Cristóbal Island (14 from each site). Of these turtles, 20 were immature and of unknown sex; the other eight were males (five mature, three immature). A portable blood analyzer (iSTAT) was used to obtain near immediate field results for pH, lactate, pO2, pCO2, HCO3-, Hct, Hb, Na, K, iCa, and Glu. Parameter values affected by temperature were corrected in two ways: (1) with standard formulas; and (2) with auto-corrections made by the iSTAT. The two methods yielded clinically equivalent results. Standard laboratory hematology techniques were employed for the red and white blood cell counts and the hematocrit determination, which was also compared to the hematocrit values generated by the iSTAT. Of all blood analytes, only lactate concentrations were positively correlated with body size. All other values showed no significant difference between the two sample locations nor were they correlated with body size or internal temperature. For hematocrit count, the iSTAT blood analyzer yielded results indistinguishable from those obtained with high-speed centrifugation. The values reported in this study provide baseline data that may be useful in comparisons among populations and in detecting changes in health status among Galapagos sea turtles. The findings might also be helpful in future efforts to demonstrate associations between specific biochemical parameters and disease. PMID:24824065

  10. Hydrothermal alteration in oceanic ridge volcanics: A detailed study at the Galapagos Fossil Hydrothermal Field

    SciTech Connect

    Ridley, W.I.; Perfit, M.R.; Smith, M.F.; Jonasson, I.R.

    1994-06-01

    The Galapagos Fossil Hydrothermal Field is composed of altered oceanic crust and extinct hydrothermal vents within the eastern Galapagos Rift between 85{degree}49 feet W and 85{degree} 55 feet W. The discharge zone of the hydrothermal system is revealed along scarps, thus providing an opportunity to examine the uppermost mineralized, and highly altered interior parts of the crust. Altered rocks collected in situ by the submersible ALVIN show complex concentric alteration zones. Microsamples of individual zones have been analysed for major/minor, trace elements, and strontium isotopes in order to describe the complex compositional details of the hydrothermal alteration. Interlayered chlorite-smectite and chlorite with disequilibrium compositions dominate the secondary mineralogy as replacement phases of primary glass and acicular pyroxene. Phenocrysts and matrix grains of plagioclase are unaffected during alteration. Using a modification of the Gresens` equation we demonstrate that the trivalent rare earth elements (REEs) are relatively immobile, and calculate degrees of enrichment and depletion in other elements. Strontium isotopic ratios increase as Sr concentrations decrease from least-altered cores to most-altered rims and cross-cutting veins in individual samples, and can be modeled by open system behaviour under low fluid-rock ratio (<10) conditions following a period of lower-temperature weathering of volcanics within the rift zone. The complex patterns of element enrichment and depletion and strontium isotope variations indicate mixing between pristine seawater and ascending hot fluids to produce a compositional spectrum of fluids. If, as suggested here, the discharge zone alteration occurred under relatively low fluid-rock ratios, then this shallow region must play an important role in determining the exit composition of vent fluids in marine hydrothermal systems. 50 refs., 10 figs., 4 tabs.

  11. Distributed deformation ahead of the Cocos-Nazca Rift at the Galapagos triple junction

    NASA Astrophysics Data System (ADS)

    Smith, Deborah K.; Schouten, Hans; Zhu, Wen-lu; Montési, Laurent G. J.; Cann, Johnson R.

    2011-11-01

    The Galapagos triple junction is not a simple ridge-ridge-ridge (RRR) triple junction. The Cocos-Nazca Rift (C-N Rift) tip does not meet the East Pacific Rise (EPR). Instead, two secondary rifts form the link: Incipient Rift at 2°40‧N and Dietz Deep volcanic ridge, the southern boundary of the Galapagos microplate (GMP), at 1°10‧N. Recently collected bathymetry data are used to investigate the regional tectonics prior to the establishment of the GMP (∼1.5 Ma). South of C-N Rift a band of northeast-trending cracks cuts EPR-generated abyssal hills. It is a mirror image of a band of cracks previously identified north of C-N Rift on the same age crust. In both areas, the western ends of the cracks terminate against intact abyssal hills suggesting that each crack initiated at the EPR spreading center and cut eastward into pre-existing topography. Each crack formed a short-lived triple junction until it was abandoned and a new crack and triple junction initiated nearby. Between 2.5 and 1.5 Ma, the pattern of cracking is remarkably symmetric about C-N Rift providing support for a crack interaction model in which crack initiation at the EPR axis is controlled by stresses associated with the tip of the westward-propagating C-N Rift. The model also shows that offsets of the EPR axis may explain times when cracking is not symmetric. South of C-N Rift, cracks are observed on seafloor as old as 10.5 Ma suggesting that this triple junction has not been a simple RRR triple junction during that time.

  12. Poor transferability of species distribution models for a pelagic predator, the grey petrel, indicates contrasting habitat preferences across ocean basins.

    PubMed

    Torres, Leigh G; Sutton, Philip J H; Thompson, David R; Delord, Karine; Weimerskirch, Henri; Sagar, Paul M; Sommer, Erica; Dilley, Ben J; Ryan, Peter G; Phillips, Richard A

    2015-01-01

    Species distribution models (SDMs) are increasingly applied in conservation management to predict suitable habitat for poorly known populations. High predictive performance of SDMs is evident in validations performed within the model calibration area (interpolation), but few studies have assessed SDM transferability to novel areas (extrapolation), particularly across large spatial scales or pelagic ecosystems. We performed rigorous SDM validation tests on distribution data from three populations of a long-ranging marine predator, the grey petrel Procellaria cinerea, to assess model transferability across the Southern Hemisphere (25-65°S). Oceanographic data were combined with tracks of grey petrels from two remote sub-Antarctic islands (Antipodes and Kerguelen) using boosted regression trees to generate three SDMs: one for each island population, and a combined model. The predictive performance of these models was assessed using withheld tracking data from within the model calibration areas (interpolation), and from a third population, Marion Island (extrapolation). Predictive performance was assessed using k-fold cross validation and point biserial correlation. The two population-specific SDMs included the same predictor variables and suggested birds responded to the same broad-scale oceanographic influences. However, all model validation tests, including of the combined model, determined strong interpolation but weak extrapolation capabilities. These results indicate that habitat use reflects both its availability and bird preferences, such that the realized distribution patterns differ for each population. The spatial predictions by the three SDMs were compared with tracking data and fishing effort to demonstrate the conservation pitfalls of extrapolating SDMs outside calibration regions. This exercise revealed that SDM predictions would have led to an underestimate of overlap with fishing effort and potentially misinformed bycatch mitigation efforts. Although

  13. Poor transferability of species distribution models for a pelagic predator, the grey petrel, indicates contrasting habitat preferences across ocean basins.

    PubMed

    Torres, Leigh G; Sutton, Philip J H; Thompson, David R; Delord, Karine; Weimerskirch, Henri; Sagar, Paul M; Sommer, Erica; Dilley, Ben J; Ryan, Peter G; Phillips, Richard A

    2015-01-01

    Species distribution models (SDMs) are increasingly applied in conservation management to predict suitable habitat for poorly known populations. High predictive performance of SDMs is evident in validations performed within the model calibration area (interpolation), but few studies have assessed SDM transferability to novel areas (extrapolation), particularly across large spatial scales or pelagic ecosystems. We performed rigorous SDM validation tests on distribution data from three populations of a long-ranging marine predator, the grey petrel Procellaria cinerea, to assess model transferability across the Southern Hemisphere (25-65°S). Oceanographic data were combined with tracks of grey petrels from two remote sub-Antarctic islands (Antipodes and Kerguelen) using boosted regression trees to generate three SDMs: one for each island population, and a combined model. The predictive performance of these models was assessed using withheld tracking data from within the model calibration areas (interpolation), and from a third population, Marion Island (extrapolation). Predictive performance was assessed using k-fold cross validation and point biserial correlation. The two population-specific SDMs included the same predictor variables and suggested birds responded to the same broad-scale oceanographic influences. However, all model validation tests, including of the combined model, determined strong interpolation but weak extrapolation capabilities. These results indicate that habitat use reflects both its availability and bird preferences, such that the realized distribution patterns differ for each population. The spatial predictions by the three SDMs were compared with tracking data and fishing effort to demonstrate the conservation pitfalls of extrapolating SDMs outside calibration regions. This exercise revealed that SDM predictions would have led to an underestimate of overlap with fishing effort and potentially misinformed bycatch mitigation efforts. Although

  14. Development of homeothermy in the diving petrels Pelecanoides urinatrix exsul and P. georgicus, and the Antarctic prion Pachyptila desolata.

    PubMed

    Ricklefs, R E; Roby, D D

    1983-01-01

    Body temperatures of South Georgia diving petrel (P. georgicus) chicks increased from about 37.5 degrees C at hatching to between 38.5 and 39 degrees C within two weeks. Temperatures of common diving petrel P. u. exsul chicks averaged 38.8 degrees C after two weeks of age. Burrow temperatures varied between 5 and 10 degrees C. Measurements of oxygen consumption and body temperature indicated that chicks achieve effective endothermy at 5 degrees C after 9 days in P. u. exsul, 5-6 days in P. georgicus, and 0 days in the Antarctic prion (Pachyptila desolata). The maximum mass-specific, cold-induced oxygen consumption of small chicks that we could measure with our apparatus (ca. 5-6 cc O2/g per hr) was achieved at 5-6 days in P. u. exsul, 3 days in P. georgicus, and 0 days in P. desolata. Mass-specific thermal conductance decreased with age and body size in all 3 species, but was highest in P. u. exsul and lowest in P. desolata. Conductance was similar at the age of effective endothermy in all 3 species (ca. 3 J/g per hr per degrees C). The period required for the development of endothermy is related to age-specific changes in both conductance and capacity for heat production and it closely parallels the length of the brooding period. It is suggested that the length of the period of thermal dependence of the chick is related to the distance between feeding areas and the nesting site. PMID:6135546

  15. Status and trends of the ashy storm-petrel on Southeast Farallon Island, California, based upon capture-recapture analyses

    USGS Publications Warehouse

    Sydeman, W.J.; Nur, N.; Mclaren, E.B.; McChesney, G.J.

    1998-01-01

    We conducted a capture-recapture study on the population size and trends of the Ashy Storm-petrel (Oceanodroma homochroa) on Southeast Farallon Island (SEFI), California, based upon data collected in 1971, 1972, and 1992. From March through August, birds were lured to fixed-site sampling locations using taped vocalization playback. Using program JOLLY, we estimated population size and evaluated statistical models using goodness-of-fit and Likelihood Ratio tests. On the southwestern slope of Lighthouse Hill, amidst prime breeding habitat, numbers of breeding birds decreased from 1,271 ?? 140 (?? ?? SE) in 1972 to 710 ?? 117 in 1992, a decline of 44% (approximate 95% CI = 22-66% decline; ?? = -2.8% per annum); for a variety of reasons, we consider this to be the most reliable indicator of population change. In 1971, on a portion of SEFI relatively disjunct from the sampling area in 1972, 2,131 ?? 322 breeding birds were estimated. To produce an overall early 1970s estimate with which to compare to 1992, we summed population estimates from 1971 and 1972. An overall value of 6,461 birds, of which 3,402 (53%) were breeders, was obtained for the early period. In 1992, the overall population in roughly the same area was estimated at 4,284 ?? 409 birds, of which 1,990 ?? 408 (46%) were presumed breeders. These results, encompassing peripheral as well as more centrally located storm-petrel habitat, indicate an overall population decline of 34% and a comparable decline in breeding birds of 42% over the past two decades. However, oceanographic conditions varied between 1971-1972 and 1992, and reduced food availability in 1992 may have influenced colony attendance and breeding effort. Nonetheless, the apparent population decline over the past 20 years suggests that the species warrants management and/or additional protective status.

  16. Poor Transferability of Species Distribution Models for a Pelagic Predator, the Grey Petrel, Indicates Contrasting Habitat Preferences across Ocean Basins

    PubMed Central

    Torres, Leigh G.; Sutton, Philip J. H.; Thompson, David R.; Delord, Karine; Weimerskirch, Henri; Sagar, Paul M.; Sommer, Erica; Dilley, Ben J.; Ryan, Peter G.; Phillips, Richard A.

    2015-01-01

    Species distribution models (SDMs) are increasingly applied in conservation management to predict suitable habitat for poorly known populations. High predictive performance of SDMs is evident in validations performed within the model calibration area (interpolation), but few studies have assessed SDM transferability to novel areas (extrapolation), particularly across large spatial scales or pelagic ecosystems. We performed rigorous SDM validation tests on distribution data from three populations of a long-ranging marine predator, the grey petrel Procellaria cinerea, to assess model transferability across the Southern Hemisphere (25-65°S). Oceanographic data were combined with tracks of grey petrels from two remote sub-Antarctic islands (Antipodes and Kerguelen) using boosted regression trees to generate three SDMs: one for each island population, and a combined model. The predictive performance of these models was assessed using withheld tracking data from within the model calibration areas (interpolation), and from a third population, Marion Island (extrapolation). Predictive performance was assessed using k-fold cross validation and point biserial correlation. The two population-specific SDMs included the same predictor variables and suggested birds responded to the same broad-scale oceanographic influences. However, all model validation tests, including of the combined model, determined strong interpolation but weak extrapolation capabilities. These results indicate that habitat use reflects both its availability and bird preferences, such that the realized distribution patterns differ for each population. The spatial predictions by the three SDMs were compared with tracking data and fishing effort to demonstrate the conservation pitfalls of extrapolating SDMs outside calibration regions. This exercise revealed that SDM predictions would have led to an underestimate of overlap with fishing effort and potentially misinformed bycatch mitigation efforts. Although

  17. Possible Impacts of the Invasive Plant Rubus niveus on the Native Vegetation of the Scalesia Forest in the Galapagos Islands

    PubMed Central

    Rentería, Jorge Luis; Gardener, Mark R.; Panetta, F. Dane; Atkinson, Rachel; Crawley, Mick J.

    2012-01-01

    Originally from Asia, Rubus niveus has become one of the most widespread invasive plant species in the Galapagos Islands. It has invaded open vegetation, shrubland and forest alike. It forms dense thickets up to 4 m high, appearing to displace native vegetation, and threaten the integrity of several native communities. This study used correlation analysis between a R. niveus cover gradient and a number of biotic (vascular plant species richness, cover and vegetation structure) and abiotic (light and soil properties) parameters to help understand possible impacts in one of the last remaining fragments of the Scalesia forest in Santa Cruz Island, Galapagos. Higher cover of R. niveus was associated with significantly lower native species richness and cover, and a different forest structure. Results illustrated that 60% R. niveus cover could be considered a threshold for these impacts. We suggest that a maximum of 40% R. niveus cover could be a suitable management target. PMID:23118934

  18. Description of a New Galapagos Giant Tortoise Species (Chelonoidis; Testudines: Testudinidae) from Cerro Fatal on Santa Cruz Island.

    PubMed

    Poulakakis, Nikos; Edwards, Danielle L; Chiari, Ylenia; Garrick, Ryan C; Russello, Michael A; Benavides, Edgar; Watkins-Colwell, Gregory J; Glaberman, Scott; Tapia, Washington; Gibbs, James P; Cayot, Linda J; Caccone, Adalgisa

    2015-01-01

    The taxonomy of giant Galapagos tortoises (Chelonoidis spp.) is currently based primarily on morphological characters and island of origin. Over the last decade, compelling genetic evidence has accumulated for multiple independent evolutionary lineages, spurring the need for taxonomic revision. On the island of Santa Cruz there is currently a single named species, C. porteri. Recent genetic and morphological studies have shown that, within this taxon, there are two evolutionarily and spatially distinct lineages on the western and eastern sectors of the island, known as the Reserva and Cerro Fatal populations, respectively. Analyses of DNA from natural populations and museum specimens, including the type specimen for C. porteri, confirm the genetic distinctiveness of these two lineages and support elevation of the Cerro Fatal tortoises to the rank of species. In this paper, we identify DNA characters that define this new species, and infer evolutionary relationships relative to other species of Galapagos tortoises.

  19. Description of a New Galapagos Giant Tortoise Species (Chelonoidis; Testudines: Testudinidae) from Cerro Fatal on Santa Cruz Island

    PubMed Central

    Chiari, Ylenia; Garrick, Ryan C.; Russello, Michael A.; Benavides, Edgar; Watkins-Colwell, Gregory J.; Glaberman, Scott; Tapia, Washington; Gibbs, James P.; Cayot, Linda J.; Caccone, Adalgisa

    2015-01-01

    The taxonomy of giant Galapagos tortoises (Chelonoidis spp.) is currently based primarily on morphological characters and island of origin. Over the last decade, compelling genetic evidence has accumulated for multiple independent evolutionary lineages, spurring the need for taxonomic revision. On the island of Santa Cruz there is currently a single named species, C. porteri. Recent genetic and morphological studies have shown that, within this taxon, there are two evolutionarily and spatially distinct lineages on the western and eastern sectors of the island, known as the Reserva and Cerro Fatal populations, respectively. Analyses of DNA from natural populations and museum specimens, including the type specimen for C. porteri, confirm the genetic distinctiveness of these two lineages and support elevation of the Cerro Fatal tortoises to the rank of species. In this paper, we identify DNA characters that define this new species, and infer evolutionary relationships relative to other species of Galapagos tortoises. PMID:26488886

  20. Interactions between the Avian Parasite, Philornis downsi (Diptera: Muscidae) and the Galapagos Flycatcher, Myiarchus magnirostris Gould (Passeriformes: Tyrannidae).

    PubMed

    Lincango, Piedad; Causton, Charlotte; Cedeño, Daniel; Castañeda, Johanna; Hillstrom, Alexandra; Freund, Deborah

    2015-10-01

    An incidental observation of the fly Philornis downsi parasitizing a Galapagos Flycatcher (Myiarchus magnirostris) nest has revealed new insights into the searching behavior and biology of this invasive fly parasite and its interactions with endemic landbirds in the Galapagos Islands. Observations suggest that P. downsi relies on olfactory cues, or olfactory cues combined with the activity of adult birds, to locate nests and that flies continue to visit nests when chicks are >3 d old. At least 200 eggs were laid by P. downsi in different parts of the nest and >40 early-instar larvae were found inside the head of one chick, with additional larvae found in the base of the nest. Parasitism was the likely cause of mortality of both chicks found in or near the nest. This description of P. downsi parasitizing chicks of M. magnirostris highlights the vulnerability of this endemic bird species to this invasive fly.

  1. Equatorial paleosecular variation of the geomagnetic field from 0 to 3 Ma lavas from the Galapagos Islands

    NASA Astrophysics Data System (ADS)

    Kent, Dennis V.; Wang, Huapei; Rochette, Pierre

    2010-12-01

    Complete progressive thermal demagnetization of nearly 400 oriented samples from 58 sites (lava flows) from the Galapagos Islands of Santa Cruz, San Cristobal and Floreana provide data for the statistical characterization of the time-averaged geomagnetic field near the Equator for the past few million years. Estimates of VGP dispersion due to paleosecular variation range from 9.2° to 11.8° depending on site selection criteria; our preferred estimate based on 64 site VGPs (51 accepted from this study and 13 from the 1971 study by Cox) is 11.4° (95% confidence interval 10.2-13.0°), consistent with previous estimates from the Galapagos Islands as well as paleosecular variation Model G, and confirming that angular dispersion of VGPs near the Equator is relatively low. The mean direction is not significantly different from a geocentric axial dipole field when account is taken of southward plate motion over the Galapagos hotspot. Preliminary paleointensity results from a comparison of the natural remanence with a total thermal remanence produced in a lab field of 15 μT on a subset of 321 samples from 48 sites that had relatively small changes in magnetic susceptibility after laboratory heating suggest that the time-averaged field was about 21 μT, or only two-thirds the present strength, in agreement with some other recent estimates.

  2. Urban life of Galapagos sea lions (Zalophus wollebaeki) on San Cristobal Island, Ecuador: colony trends and threats

    NASA Astrophysics Data System (ADS)

    Denkinger, Judith; Gordillo, Luis; Montero-Serra, Ignasi; Murillo, Juan Carlos; Guevara, Nataly; Hirschfeld, Maximilian; Fietz, Katharina; Rubianes, Francisco; Dan, Michael

    2015-11-01

    Worldwide, pristine environments are influenced by human societies. In the Galapagos Islands, the endangered, endemic Galapagos sea lion (Zalophus wollebaeki) has formed one of the biggest colonies within the town center of Puerto Baquerizo Moreno. About 8,000 people live there and human wildlife interactions occur daily. With colony counts and direct observations from 2008 to 2012, we analyze cause of death, injuries and disease of urban sea lion colonies at Wreck Bay. Population increase since 2008 can be attributed to an immigration of adult sea lions in 2010, resulting in an increase in the pup and juvenile production in 2011 and 2012. Pup mortality increased drastically to 2009 and again in 2011 and 2012. Besides pup mortality, most of the deaths are caused by increased disease incidences and human activity. Our observations suggest that overall 65% of the injuries observed are produced by human interaction. The increase in threats leading to death, injuries or disease can have long-term effects on the population. Although threats that cause physical injuries can be managed locally, sea lions range movements contributes to the spread of infectious pathogens, which may affect neighbor colonies and potentially have an impact on the survival of the species. Our study reveals the need of stronger efforts towards a more complete understanding of threats and especially disease spread among Galapagos Sea lions in urban environments and the establishment of more effective management measures.

  3. Influx of Different Galapagos Plume Components to the Galapagos Spreading Center: Evidence From Sr-Nd-Pb-Hf Isotope Variations in Axial Lavas Between 86W and 92.5W

    NASA Astrophysics Data System (ADS)

    Hauff, F.; Hanan, B.; Hoernle, K. A.; Kokfelt, T. F.; Christie, D.; Werner, R.

    2006-12-01

    We present new Sr-Nd-Pb-Hf isotope data of basaltic glasses from the GSC between 86W and 92.5W. In this part of the ridge the main structural inventory includes an overlapping spreading center (OSC) at 87.3W, a transform fault (TF) at 91W and a series of seamount chains intersecting the GSC West of the 91W TF. The systematic transition from an axial-valley and rift morphology at axial depths of 2450 m.b.s.l. in the 86W area to an axial-high morphology at progressively shallower depths of 1500 m.b.s.l in the 90.5W area together with gradational changes in major and trace element chemistry of the axial lavas is believed to reflect increasing mantle temperature and compositional changes related to the Galapagos plume [1]. Previous work from 83W to 105W revealed a broad symmetric gradational pattern at around 91W and lead to the conclusion that this region is the main point of plume influx on the GSC [2]. Based on published isotope data Christie et al. (2005) inferred the probable existence of two enrichment peaks immediately East and West of the 91TF. Indeed, along axis variations of our new Sr-Nd-Pb-Hf isotope data map two distinct peaks of enrichment at 92W and 90.5W, suggesting that mantle from the Galapagos hotspot enters the GSC melting zone on both sides of the 91W transform fault. Lavas from within the 91W TF are isotopically intermediate and show a distinct depletion in incompatible trace elements, which may reflect repeated melting at shallow depth of passively upwelling mantle in this unique extensional regime. At least three different components are required to generate the observed isotope correlations. When compared to the geographically distinct isotopic domains of the Galapagos islands; GSC lavas East of the 91W TF form tight correlations from the rim of the Central Galapagos domain through the Eastern Galapagos domain towards DMM. Most axial lavas and corresponding off axis seamounts West of the 91W TF have higher 87Sr/86Sr, 207Pb/204Pb, 208Pb/204Pb

  4. The role of small-scale extensional faulting in the evolution of basin geometries. An example from the late Palaeozoic Petrel Sub-basin, northwest Australia

    NASA Astrophysics Data System (ADS)

    Baxter, K.

    1998-03-01

    During continental extension, the kinematic collapse of the hangingwall of major normal faults and the subsequent isostatic response imposes a strong control on the evolving basin geometry. The interaction of the flexural wavelength. and the magnitude and location of faults may allow the development of basin geometries which deviate from a classic half-graben style, particularly if some of this deformation is below the scale of observation (commonly seismic reflection data). In particular the development of a lateral partitioning between large- and small-scale faults within a basin may exert a significant control on the resulting basin geometry. Using the Petrel Sub-basin in northwest Australia as an example, it is demonstrated that an extensional basin geometry consisting of a classic half-graben can be overprinted by a significant 'sag' geometry which can be related to the lateral offset of sub-resolution faulting. This lateral partitioning and resulting basin geometry may also have an application to other extensional basins, particularly if a mechanism is present to allow this partitioning of fault styles to develop. In the Petrel Sub-basin this has been related to the presence of older basement features of the Halls Creek Mobile Zone beneath the axis of the basin. However, a comparison with physical models also suggests that this may be applicable to basins formed by oblique rifting (a component of which may also be present within the Petrel Sub-basin), particularly if this is imposed upon a weak zone or suture within the upper mantle.

  5. Adaptation, isolation by distance and human-mediated transport determine patterns of gene flow among populations of the disease vector Aedes taeniorhynchus in the Galapagos Islands.

    PubMed

    Bataille, Arnaud; Cunningham, Andrew A; Cruz, Marilyn; Cedeño, Virna; Goodman, Simon J

    2011-12-01

    The black salt-marsh mosquito (Aedes taeniorhynchus) is the only native mosquito in the Galapagos Islands and potentially a major disease vector for Galapagos wildlife. Little is known about its population structure, or how its dynamics may be influenced by human presence in the archipelago. We used microsatellite data to assess the structure and patterns of A. taeniorhynchus gene flow among and within islands, to identify potential barriers to mosquito dispersal, and to investigate human-aided transport of mosquitoes across the archipelago. Our results show that inter-island migration of A. taeniorhynchus occurs frequently on an isolation by distance basis. High levels of inter-island migration were detected amongst the major ports of the archipelago, strongly suggesting the occurrence of human-aided transport of mosquitoes among islands, underlining the need for strict control measures to avoid the transport of disease vectors between islands. The prevalence of filarial nematode infection in Galapagos flightless cormorants is correlated with the population structure and migration patterns of A. taeniorhynchus, suggesting that A. taeniorhynchus is an important vector of this arthropod-borne parasite in the Galapagos Islands. Therefore mosquito population structure in Galapagos may have the potential to influence mosquito-borne parasite population dynamics, and the subsequent impacts of such pathogens on their host species in the islands.

  6. Geomagnetic paleointensity constraints on eruption timing at the Galapagos Spreading Center

    NASA Astrophysics Data System (ADS)

    Bowles, J. A.; Ab Fatah, A.; Colman, A.; McClinton, J. T.; Sinton, J. M.; White, S. M.; Rubin, K. H.

    2011-12-01

    The intermediate-spreading-rate Galapagos Spreading Center (GSC) experiences decreasing magma supply along axis with increasing distance from the nearby Galapagos hotspot. This allows us to explore the effects of variable magma supply on eruptive frequency, size, and style. Two contrasting sites on the GSC were mapped using high-resolution swath bathymetry, submersible observations, and camera tow photography. Individual eruptive units have been identified on the basis of these data and observations, as well sample geochemistry. In order to construct an eruptive history and to make broader interpretations regarding eruptive processes, it is necessary to place relative and absolute age constraints on these units. We present age determinations derived from geomagnetic paleointensity experiments at one of the study sites, centered at ~91°55'W, where increased magma supply from the hotspot results in an axial high. Due to the near monotonic decrease in geomagnetic paleointensity over the past ~500+ years, it is possible to infer relative age and to place approximate age constraints on eruptive units on the basis of their experimentally-determined paleointensity. Four of the largest identified units have been selected as a test case. Results suggest that the youngest flow is approximately 40 ± 30 years old. This flow unit is ~5 km long by 1 km wide, centered on the rise axis. An older flow (~180 ± 30 years old), also centered along the rise axis, lies to the west and its ~7 km along-axis exposure is interrupted by a large, flat-topped seamount. A number of active hydrothermal chimneys sit atop this flow unit, the heat source for which we infer to be related to the younger flow to the east or to a more recent shallow intrusion. The oldest documented flow is roughly 400 years old and is exposed slightly off-axis to the north of the two younger flows. The paleointensity-derived flow ages are consistent with available geological constraints on relative age. Based on

  7. Hydrodynamic properties of the basal aquifer of Santa Cruz Island using seismic refraction, Galapagos - Ecuador

    NASA Astrophysics Data System (ADS)

    Loaiza, S.; Fortin, J.; Adelinet, M.; Guéguen, Y.; Violette, S.

    2012-04-01

    Santa Cruz Island is the most inhabited of the Galapagos archipelago, Ecuador. It faces important water resource problems which might lead to a major impact on their unique and pristine ecosystem, Endangered World Heritage list (2007). The scarcity of geological and hydrological data combined with the difficulty of access for field measurements lead to a poor understanding of the island hydrogeology. The Island is formed by series of thick fractured basaltic lava flows dissected by faults. The low-lying, extensive "basal" aquifer is the unique groundwater body identified on the island. This basal aquifer is subjected to sea-water intrusion, which has been mapped from electrical resistivity imaging with an airborne electromagnetic SkyTEM survey (D'Ozouville et al. 2008). In order to better understand the hydrodynamic properties of the basal aquifer, we acquired, in summer 2011, geophysical data based on seismic refraction. The experiment was conducted on three study sites located at different altitudes above the see level (Beagle site altitude +7m , Mirador +20m, and Villacis +393m). The P-wave refraction data were obtained using 24 geophones (1 component) and an acquisition system Daklink III. A hammer was used as an energy source. This source was the most environmentally friendly source that could be obtained and used in the Galapagos Island. Geophone spacing for the spreads was 1.2 or 5 m depending on the site. From our geophysical data, we could identify the different geological layers that constitute this basal aquifer and to estimate the thickness of these layers. We could as well clearly see the water level in the aquifer. More interesting, we found a P-wave velocity of ~1600 m/s in the dry fractured basalt lava flow, and a P-wave velocity of ~2700 m/s in the water saturated fractured basalt lava flow. The same velocity values were obtained in the different sites. This tends to show that the elastic properties of the aquifer are homogeneous and isotropic (at

  8. Seismic Analysis of Magmatism in the Galapagos Archipelago and East Africa

    NASA Astrophysics Data System (ADS)

    Tepp, Gabrielle

    Magmatism and deformation are consequences of fundamental processes shaping Earth's ˜150 km-thick continental and <125 km-thick oceanic plates. Earthquake seismology encompasses many methods to detect compositional and thermal boundaries from Earth's surface to the dynamic mantle driving plate tectonics. This work uses three different seismic methods to probe magma migration and storage and tectonism in two intraplate hotspot provinces: the Galapagos and East Africa. First, seismic body-wave tomography is used to image magma within oceanic crust of the largest Galapagos volcano, Sierra Negra. A laterally large, low-velocity region with many smaller, high-magnitude velocity anomalies is imaged at 8--15.5 km depths. No sharp seismic velocity increase is imaged within the resolvable depths, indicating that the thickened crust is at least 16 km deep. The second study involves a spectral analysis of earthquakes induced by the intrusion of thin sheets of magma rising beneath the Afar rift, East Africa. Earthquakes have varying spectral content, some with unusually large amplitude low-frequency content and enhanced surface waves. The analysis showed no clear boundaries between spectral types, suggesting that they are all primarily the result of brittle failure. Deep dike segments (tops > 3 km) induce only high-frequency volcano-tectonic earthquakes, while shallower dike segments induce the full range of spectral types. This suggests that low-frequency content is a result of shallow hypocenters, with path and site effects, surface ruptures, and dike fluid interactions all possible secondary causes. In the final study, shear-wave splitting analysis of teleseismic body-wave phases is conducted to evaluate strain and crack fabrics at the base of the continental plate as a consequence of magmatism, mantle flow, and plate stretching in the Western rift, East Africa. On average, fast directions are northeast, consistent with geodynamic models of mantle flow from the African

  9. Physiological and ecological consequences of sleeping-site selection by the Galapagos land iguana (Conolophus pallidus)

    SciTech Connect

    Christian, K.A.; Tracy, C.R.

    1984-01-01

    Field observations and biophysical models were combined to analyze sleeping-site selection by Galapagos land iguanas (Conolophus pallidus). Iguanas slept in different kinds of sleeping sites during different seasons. In the coolest season (garua), adult land iguanas were found in sleeping sites that were warmer than the coolest sites available. This may be because the garua season (cool, overcast, and foggy) is a time when environmental conditions mitigate against rapid warm-up in the mornings, so lizards may regulate nighttime body temperatures so that it is easier to warm up to preferred daytime body temperatures. In the warmest season, adult iguanas were found in the coolest sleeping sites available. This observation is consistent with hypotheses of voluntary hypothermia, which can be advantageous in energy conservation and in avoiding detrimental effects associated with maintenance of constant body temperatures throughout the day and night. Juvenile iguanas were found sleeping in rock crevices regardless of the ambient thermal environments. Such sites are likely to be important as refugia for this life stage, which, unlike the adult stage, is vulnerable to predation. It was concluded that selection of sleeping sites is a process that may help in avoidance of predation, optimization of body temperature at the end of the sleeping period, and reduction of metabolic costs during sleeping. The importance of some of these factors may change with the thermal milieu (e.g., season).

  10. Oxygen and carbon isotope disequilibria in Galapagos corals: isotopic thermometry and calcification physiology

    SciTech Connect

    McConnaughey, T.A.

    1986-01-01

    Biological carbonate skeletons are built largely from carbon dioxide, which reacts to form carbonate ion within thin extracellular solutions. The light isotopes of carbon and oxygen react faster than the heavy isotopes, depleting the resulting carbonate ions in /sup 13/C and /sup 18/O. Calcium carbonate precipitation occurs sufficiently fast that the skeleton remains out of isotopic equilibrium with surrounding fluids. This explanation for isotopic disequilibrium in biological carbonates was partially simulated in vitro, producing results similar to those seen in non-photosynthetic corals. Photosynthetic corals have higher /sup 13/C//sup 12/C ratios due to the preferential removal of /sup 12/C (as organic carbon) from the reservoir of dissolved inorganic carbon. The oxygen isotopic variations in corals can be used to reconstruct past sea surface temperatures to an accuracy of about 0.5/sup 0/C. The carbon isotopic content of photosynthetic corals provides an indication of cloudiness. Using isotopic data from Galapagos corals, it was possible to construct proxy histories of the El Nino phenomenon. The physiology of skeletogenesis appears to be surprisingly similar in calcium carbonate, calcium phosphate, and silica precipitating systems.

  11. 238U, 226Ra and 210Pb in some vent waters of the Galapagos Spreading Center

    NASA Astrophysics Data System (ADS)

    Krishnaswami, S.; Turekian, K. K.

    1982-08-01

    The concentrations of 226Ra, 238U and 210Pb have been measured in waters from the Mussel Bed and the Rose Garden thermal fields at the Galapagos spreading center over a temperature range of ˜2.5-16°C. The 226Ra-T plots yield slopes of 0.112 and 0.036 dpm/kg°C for the Mussel Bed and the Rose Garden respectively yielding a global hydrothermal 226Ra flux less than 5% of that required to sustain the oceanic inventory. 238U concentration in waters <9°C is the same as that in ambient sea water whereas water hotter than ˜9°C shows a decreasing trend with temperature to zero 238U at ˜29°C. 210Pb concentration in Mussel Bed increases with temperature, and extrapolated to ˜350°C yields a 210Pb concentration considerably less than that expected from 222Rn decay and basalt alteration.

  12. Chemical and biological interactions in the Rose Garden hydrothermal vent field, Galapagos spreading center

    NASA Astrophysics Data System (ADS)

    Johnson, Kenneth S.; Childress, James J.; Hessler, Robert R.; Sakamoto-Arnold, Carole M.; Beehler, Carl L.

    1988-10-01

    The concentrations of a suite of redox reactive chemicals were measured in the Rose Garden hydrothermal vent field of the Galapagos spreading center. Sulfide, silicate, oxygen and temperature distributions were measured in situ with a submersible chemical analyser. In addition, 15 chemical species were measured in discrete samples. Variability in the slope of the temperature-silicate plots indicates that heat is lost from these relatively low temperatures (<15°C) solutions by conduction to the solid phase. Consumption of oxygen, sulfide and nitrate from the hydrothermal solution as it flows past the vent animals is apparent from the distributions measured in situ and in the discrete samples. The fraction of sulfide and nitrate removed from the solution by consumption appears to have increased between 1979-1985. Sulfide and oxygen appear to be consumed under different conditions: sulfide is removed primarily from the warmest solutions, and oxygen is consumed only from the cold seawater. This separation may be driven primarily by the increased gradients of each chemical under these conditions. There is no evidence for the consumption of significant amounts of manganese(II) by the vent organisms. The analysis of other data sets from this vent field indicate no significant consumption of methane by the vent organisms, as well.

  13. Hotspots within hotspots? Hammerhead shark movements around Wolf Island, Galapagos Marine Reserve.

    PubMed

    Hearn, Alex; Ketchum, James; Klimley, A Peter; Espinoza, Eduardo; Peñaherrera, Cesar

    2010-01-01

    Are pelagic species such as sharks and tuna distributed homogenously or heterogeneously in the oceans? Large assemblages of these species have been observed at seamounts and offshore islands in the eastern tropical Pacific, which are considered hotspots of pelagic biodiversity. Is the species distribution uniform at these hotspots or do species aggregate at a finer spatial scale at these sites? We employed three techniques to demonstrate that the aggregations of scalloped hammerhead sharks, Sphyrna lewini, and other pelagic species were confined to the southeastern corner of Wolf Island in the Galapagos Marine Reserve. Coded ultrasonic transmitters were placed on individuals at this site and at another aggregation site at Darwin Island, separated from Wolf by 40 km, and they were detected by monitors moored at the southeastern corner of Wolf Island and rarely by monitors deployed at other sites around the island. Hammerhead sharks, carrying depth-sensing continual transmitters, were tracked for two-day periods in a vessel and shown to reside a disproportionately large fraction of their time at the southeastern corner. Visual censuses were carried out seasonally at the eight monitor sites at Wolf Island, recording the abundance of one species of tuna, four species of jacks, and a number of other species. The highest diversity and abundance of these species occurred in the southeastern corner of the island. Our results support the use of hammerhead sharks as indicator and umbrella species for pelagic hotspots on a fine scale. PMID:24391250

  14. Three dimensional image of Isla Isabela in the western Galapagos Islands

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a three-dimensional image of Isla Isabela in the western Galapagos Islands off the western coast of Ecuador, South America. The view was constructed by overlaying a Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar image on a TOPSAR digital elevation map. The vertical scale in this image is exaggerated by a factor of 1.87. The SIR-C/X-SAR image was taken on the 40th orbit of the shuttle Endeavour. The image is centered at about .5 degrees south latitude and 91 degrees West longitude and covers an area of 75 km by 60 km. The radar incidence angle at the center of the image is about 20 degrees. This SIR-C/X-SAR image of Alcedo and Sierra Negra volcanoes shows the rougher lava flowas as bright features, while ash deposits and smooth Pahoehoe lava flows appear dark. A small portion of Isla Fernandina is visible in the extreme upper left corner of the image. The Jet Propulsion Laboratory alternative photo number is P-43913.

  15. Hotspots within hotspots? Hammerhead shark movements around Wolf Island, Galapagos Marine Reserve.

    PubMed

    Hearn, Alex; Ketchum, James; Klimley, A Peter; Espinoza, Eduardo; Peñaherrera, Cesar

    2010-01-01

    Are pelagic species such as sharks and tuna distributed homogenously or heterogeneously in the oceans? Large assemblages of these species have been observed at seamounts and offshore islands in the eastern tropical Pacific, which are considered hotspots of pelagic biodiversity. Is the species distribution uniform at these hotspots or do species aggregate at a finer spatial scale at these sites? We employed three techniques to demonstrate that the aggregations of scalloped hammerhead sharks, Sphyrna lewini, and other pelagic species were confined to the southeastern corner of Wolf Island in the Galapagos Marine Reserve. Coded ultrasonic transmitters were placed on individuals at this site and at another aggregation site at Darwin Island, separated from Wolf by 40 km, and they were detected by monitors moored at the southeastern corner of Wolf Island and rarely by monitors deployed at other sites around the island. Hammerhead sharks, carrying depth-sensing continual transmitters, were tracked for two-day periods in a vessel and shown to reside a disproportionately large fraction of their time at the southeastern corner. Visual censuses were carried out seasonally at the eight monitor sites at Wolf Island, recording the abundance of one species of tuna, four species of jacks, and a number of other species. The highest diversity and abundance of these species occurred in the southeastern corner of the island. Our results support the use of hammerhead sharks as indicator and umbrella species for pelagic hotspots on a fine scale.

  16. Differential use of the Argentine shelf by wintering adults and juveniles southern giant petrels, Macronectes giganteus, from Patagonia

    NASA Astrophysics Data System (ADS)

    Blanco, Gabriela S.; Quintana, Flavio

    2014-08-01

    To study habitat use and at-sea movements of southern giant petrels (SGP) during non-breeding period, we deployed 15 satellite transmitters (six adults, nine juveniles) at Isla Arce and Isla Gran Robredo colonies in Patagonia, Argentina. Birds were instrumented during 81.4 ± 37 days. Adult birds used 74% of the Argentine shelf concentrating mainly at the shelf break, middle shelf waters, and the surroundings of the colony. After fledging, juveniles spread to the Argentine, Uruguayan and Brazilian shelves within the South Atlantic. Adults alternated at-sea excursions (12 ± 5 days) with periods at the colony of 3 ± 0.3 days. Contrarily, juveniles moved first to the shelf break and then traveled northwards reaching the south of Brazil. There was some spatial overlap between age classes, but only during the first 30 days after juveniles had fledged; thereafter there was not overlap between the areas used by both age classes. The Argentine shelf is widely used by different species offering a suitable environment for foraging; this may be why adults SGP from Patagonian colonies spend all year-round within the Argentine shelf. The identification of used areas of non-breeding SGP fills a gap in the species knowledge contributing not only to the preservation the species, but also to the management of marine areas globally recognized as important for many other Procellariiformes.

  17. New species of the feather mite genus Promegninia Gaud & Atyeo (Acari: Avenzoariidae) from petrels and shearwaters (Procellariiformes: Procellariidae).

    PubMed

    Mironov, Sergey V; Stefan, Laura M; González-Solís, Jacob

    2015-01-01

    Two new species of the feather mite genus Promegninia Gaud & Atyeo, 1967 (Avenzoariidae: Bonnetellinae) are described from procellariids in the northeasterm Atlantic Ocean: Promegninia bulweriae n. sp. from the Bulwer's petrel Bulweria bulwerii (Jardine & Selby) and P. calonectris n. sp. from the Cory's shearwater Calonectris borealis (Cory) (Procellariiformes: Procellariidae). Males of P bulweriae n. sp. are most clearly distinguished from the other known species in the genus by having short legs III extending only to the level of lobar apices and short conical tarsi III with lanceolate ventral seta w; females of this species are characterised by the absence of additional sclerites at postero-lateral angles of the prodorsal shield. Males of P. calonectris differ from the other known species in having bidentate terminal lamellae on the lobar apices and the entire adanal shield; females of this species are distinguished by having well-developed pygidial shields and a hysteronotal shield encompassing the bases of setae c2. Sequence data of the mitochondrial cytochrome c oxidase subunit I gene fragment (COI) are also obtained for the new species. An updated diagnosis of Promegninia and a key to the known species are provided. PMID:25557750

  18. Anonymous nuclear loci in the white-faced storm-petrel Pelagodroma marina and their applicability to other Procellariiform seabirds.

    PubMed

    Silva, Mónica C; Duarte, Margarida A; Coelho, M Manuela

    2011-01-01

    Procellariiform seabirds are among the avian species with the fastest rates of extinction due to interactions with fisheries and introduction of alien predators to the breeding colonies. Conservation and management policies targeting populations of these species must include information on colony demographics and levels of isolation and genetic markers go a long way toward providing reliable estimates of these parameters. To this end, we report isolation and characterization of 14 anonymous nuclear loci, with average length of 657 bp, in the pelagic seabird White-faced Storm-petrel Pelagodroma marina, a species for which there is virtually no genetic information available. These loci, initially isolated from a genomic library built from P. marina, were further tested, for a range of conditions, in 7 other species representing all Procellariiform families. We found high levels of cross-species amplification success, varying between 79% and 86% in representatives of Diomedeidae, Procellariidae, Pelecanoididae, and other Hydrobatidae. We also sequenced 11 loci for 22 P. marina individuals and report higher levels of anonymous genetic variation (π = 0.002), with an average of 1 single nucleotide polymorphism every 100 bp surveyed, relative to the levels found on a typically variable intron in avian species. These markers will be a valuable tool in future population genetics and phylogenetic studies, particularly of nonmodel seabird species. PMID:21447754

  19. Formation of curved seafloor fabric by changes in rift propagation velocity and spreading rate - Application to the 95.5 deg W Galapagos propagator

    NASA Technical Reports Server (NTRS)

    Acton, Gary; Stein, Seth; Engeln, Joseph F.

    1988-01-01

    Possible rigid plate models and shear models for the formation of curved seafloor lineaments by rift propagation are investigated and are applied to the Galapagos propagation rift system at 95 deg W. It is shown that the geometry noted at the Galapagos can result from either rift propagation acceleration or a spreading rate decrease during the last few hundred thousand years. It is postulated that the reverse curvature could result from either deceleration of rift propagation or an increase in spreading rate. The data interpreted as requiring a shear zone are found to be equally consistent with two distinct models based on rigid plate tectonics.

  20. Stable Isotopes Reveal Long-Term Fidelity to Foraging Grounds in the Galapagos Sea Lion (Zalophus wollebaeki).

    PubMed

    Drago, Massimiliano; Franco-Trecu, Valentina; Cardona, Luis; Inchausti, Pablo; Tapia, Washington; Páez-Rosas, Diego

    2016-01-01

    Most otariids have colony-specific foraging areas during the breeding season, when they behave as central place foragers. However, they may disperse over broad areas after the breeding season and individuals from different colonies may share foraging grounds at that time. Here, stable isotope ratios in the skull bone of adult Galapagos sea lions (Zalophus wollebaeki) were used to assess the long-term fidelity of both sexes to foraging grounds across the different regions of the Galapagos archipelago. Results indicated that the stable isotope ratios (δ(13)C and δ(15)N) of sea lion bone significantly differed among regions of the archipelago, without any significant difference between sexes and with a non significant interaction between sex and region. Moreover, standard ellipses, estimated by Bayesian inference and used as a measure of the isotopic resource use area at the population level, overlapped widely for the sea lions from the southern and central regions, whereas the overlap of the ellipses for sea lions from the central and western regions was small and non-existing for those from the western and southern regions. These results suggest that males and females from the same region within the archipelago use similar foraging grounds and have similar diets. Furthermore, they indicate that the exchange of adults between regions is limited, thus revealing a certain degree of foraging philopatry at a regional scale within the archipelago. The constraints imposed on males by an expanded reproductive season (~ 6 months), resulting from the weak reproductive synchrony among females, and those imposed on females by a very long lactation period (at least one year but up to three years), may explain the limited mobility of adult Galapagos sea lions of both sexes across the archipelago.

  1. Improved estimates of age, growth and reproduction for the regionally endemic Galapagos sailfin grouper Mycteroperca olfax (Jenyns, 1840).

    PubMed

    Usseglio, Paolo; Friedlander, Alan M; DeMartini, Edward E; Schuhbauer, Anna; Schemmel, Eva; Salinas de Léon, Pelayo

    2015-01-01

    The Galapagos Sailfin grouper, Mycteroperca olfax, locally known as bacalao and listed as vulnerable by the IUCN, is culturally, economically, and ecologically important to the Galapagos archipelago and its people. It is regionally endemic to the Eastern Tropical Pacific, and, while an important fishery resource that has shown substantial declines in recent years, to date no effective management regulations are in place to ensure the sustainability of the Galapagos fishery for this species. Previous estimates of longevity and size at maturity for bacalao are inconsistent with estimates for congeners, which brings into question the accuracy of prior estimates. We set out to assess the age, growth, and reproductive biology of bacalao in order to provide more accurate life history information to inform more effective fisheries management for this species. The oldest fish in our sample was 21 years old, which is 2-3 times greater than previously reported estimates of longevity. Parameter estimates for the von Bertalanffy growth function (k = 0.11, L ∞ = 110 cm TL, and to = - 1.7 years) show bacalao to grow much slower and attain substantially larger asymptotic maximum length than previous studies. Mean size at maturity (as female) was estimated at 65.3 cm TL, corresponding to a mean age of 6.5 years. We found that sex ratios were extremely female biased (0.009 M:1F), with a large majority of the individuals in our experimental catch being immature (79%). Our results show that bacalao grow slower, live longer, and mature at a much larger size and greater age than previously thought, with very few mature males in the population. These findings have important implications for the fishery of this valuable species and provide the impetus for a long-overdue species management plan to ensure its long-term sustainability.

  2. Stable Isotopes Reveal Long-Term Fidelity to Foraging Grounds in the Galapagos Sea Lion (Zalophus wollebaeki)

    PubMed Central

    Drago, Massimiliano; Franco-Trecu, Valentina; Cardona, Luis; Inchausti, Pablo; Tapia, Washington; Páez-Rosas, Diego

    2016-01-01

    Most otariids have colony-specific foraging areas during the breeding season, when they behave as central place foragers. However, they may disperse over broad areas after the breeding season and individuals from different colonies may share foraging grounds at that time. Here, stable isotope ratios in the skull bone of adult Galapagos sea lions (Zalophus wollebaeki) were used to assess the long-term fidelity of both sexes to foraging grounds across the different regions of the Galapagos archipelago. Results indicated that the stable isotope ratios (δ13C and δ15N) of sea lion bone significantly differed among regions of the archipelago, without any significant difference between sexes and with a non significant interaction between sex and region. Moreover, standard ellipses, estimated by Bayesian inference and used as a measure of the isotopic resource use area at the population level, overlapped widely for the sea lions from the southern and central regions, whereas the overlap of the ellipses for sea lions from the central and western regions was small and non-existing for those from the western and southern regions. These results suggest that males and females from the same region within the archipelago use similar foraging grounds and have similar diets. Furthermore, they indicate that the exchange of adults between regions is limited, thus revealing a certain degree of foraging philopatry at a regional scale within the archipelago. The constraints imposed on males by an expanded reproductive season (~ 6 months), resulting from the weak reproductive synchrony among females, and those imposed on females by a very long lactation period (at least one year but up to three years), may explain the limited mobility of adult Galapagos sea lions of both sexes across the archipelago. PMID:26808381

  3. Improved estimates of age, growth and reproduction for the regionally endemic Galapagos sailfin grouper Mycteroperca olfax (Jenyns, 1840)

    PubMed Central

    Friedlander, Alan M.; DeMartini, Edward E.; Schuhbauer, Anna; Schemmel, Eva; Salinas de Léon, Pelayo

    2015-01-01

    The Galapagos Sailfin grouper, Mycteroperca olfax, locally known as bacalao and listed as vulnerable by the IUCN, is culturally, economically, and ecologically important to the Galapagos archipelago and its people. It is regionally endemic to the Eastern Tropical Pacific, and, while an important fishery resource that has shown substantial declines in recent years, to date no effective management regulations are in place to ensure the sustainability of the Galapagos fishery for this species. Previous estimates of longevity and size at maturity for bacalao are inconsistent with estimates for congeners, which brings into question the accuracy of prior estimates. We set out to assess the age, growth, and reproductive biology of bacalao in order to provide more accurate life history information to inform more effective fisheries management for this species. The oldest fish in our sample was 21 years old, which is 2–3 times greater than previously reported estimates of longevity. Parameter estimates for the von Bertalanffy growth function (k = 0.11, L∞ = 110 cm TL, and to = − 1.7 years) show bacalao to grow much slower and attain substantially larger asymptotic maximum length than previous studies. Mean size at maturity (as female) was estimated at 65.3 cm TL, corresponding to a mean age of 6.5 years. We found that sex ratios were extremely female biased (0.009 M:1F), with a large majority of the individuals in our experimental catch being immature (79%). Our results show that bacalao grow slower, live longer, and mature at a much larger size and greater age than previously thought, with very few mature males in the population. These findings have important implications for the fishery of this valuable species and provide the impetus for a long-overdue species management plan to ensure its long-term sustainability. PMID:26401463

  4. Stable Isotopes Reveal Long-Term Fidelity to Foraging Grounds in the Galapagos Sea Lion (Zalophus wollebaeki).

    PubMed

    Drago, Massimiliano; Franco-Trecu, Valentina; Cardona, Luis; Inchausti, Pablo; Tapia, Washington; Páez-Rosas, Diego

    2016-01-01

    Most otariids have colony-specific foraging areas during the breeding season, when they behave as central place foragers. However, they may disperse over broad areas after the breeding season and individuals from different colonies may share foraging grounds at that time. Here, stable isotope ratios in the skull bone of adult Galapagos sea lions (Zalophus wollebaeki) were used to assess the long-term fidelity of both sexes to foraging grounds across the different regions of the Galapagos archipelago. Results indicated that the stable isotope ratios (δ(13)C and δ(15)N) of sea lion bone significantly differed among regions of the archipelago, without any significant difference between sexes and with a non significant interaction between sex and region. Moreover, standard ellipses, estimated by Bayesian inference and used as a measure of the isotopic resource use area at the population level, overlapped widely for the sea lions from the southern and central regions, whereas the overlap of the ellipses for sea lions from the central and western regions was small and non-existing for those from the western and southern regions. These results suggest that males and females from the same region within the archipelago use similar foraging grounds and have similar diets. Furthermore, they indicate that the exchange of adults between regions is limited, thus revealing a certain degree of foraging philopatry at a regional scale within the archipelago. The constraints imposed on males by an expanded reproductive season (~ 6 months), resulting from the weak reproductive synchrony among females, and those imposed on females by a very long lactation period (at least one year but up to three years), may explain the limited mobility of adult Galapagos sea lions of both sexes across the archipelago. PMID:26808381

  5. Isolation and characterization of 10 polymorphic microsatellite loci for the endangered Galapagos-endemic whitespotted sandbass (Paralabrax albomaculatus)

    PubMed Central

    Griffiths, Sarah M.; Truelove, Nathan K.; Box, Stephen J.; Preziosi, Richard F.; Salinas de Leon, Pelayo

    2015-01-01

    The white-spotted sandbass (Paralabrax albomaculatus) is a commercially important species in the Galapagos Marine Reserve, but is classified as endangered in the IUCN Red List. For this study, 10 microsatellite loci were isolated and characterized using Illumina paired-end sequencing. These loci can be used for genetic studies of population structure and connectivity to aid in the management of the white-spotted sandbass and other closely-related species. The 10 characterized loci were polymorphic, with 11–49 alleles per locus, and observed heterozygosity ranged from 0.575 to 0.964. This set of markers is the first to be developed for this species. PMID:26557418

  6. Isolation and characterization of 10 polymorphic microsatellite loci for the endangered Galapagos-endemic whitespotted sandbass (Paralabrax albomaculatus).

    PubMed

    Bertolotti, Alicia C; Griffiths, Sarah M; Truelove, Nathan K; Box, Stephen J; Preziosi, Richard F; Salinas de Leon, Pelayo

    2015-01-01

    The white-spotted sandbass (Paralabrax albomaculatus) is a commercially important species in the Galapagos Marine Reserve, but is classified as endangered in the IUCN Red List. For this study, 10 microsatellite loci were isolated and characterized using Illumina paired-end sequencing. These loci can be used for genetic studies of population structure and connectivity to aid in the management of the white-spotted sandbass and other closely-related species. The 10 characterized loci were polymorphic, with 11-49 alleles per locus, and observed heterozygosity ranged from 0.575 to 0.964. This set of markers is the first to be developed for this species. PMID:26557418

  7. Groundmass Crystallization of A'a and Pahoehoe flows of Cerro Azul, Galapagos and Mauna Loa, Hawaii

    NASA Astrophysics Data System (ADS)

    Teasdale, R.; Geist, D.; Wanless, D.; Cashman, K.

    2001-12-01

    Crystallinities of 1998 lavas from Cerro Azul, Galapagos are distinguished from 1843 Mauna Loa, Hawaii lavas by higher modal proportions of groundmass plagioclase crystals. In both cases, a'a lava was erupted first, followed by emplacement of pahoehoe flows. The 1843 Mauna Loa eruption lasted 90 days and produced both a'a and inflated pahoehoe flows (1). The 1998 Galapagos flows were emplaced over the course of 37 days, and the transition from a'a to pahoehoe flow morphology corresponds with decreased eruption rate during the last week of the eruption. Samples were collected along the length of flows from both volcanoes. Modal groundmass plagioclase increases down-flow for each flow type from each volcano. A'a and pahoehoe flows of Cerro Azul consistently have higher crystallinities (41% and 14%) than equivalent flow types at Mauna Loa (29% and 7%). Whereas Cerro Azul groundmass crystals are exclusively plagioclase, the groundmass of Mauna Loa lavas consists of plagioclase and pyroxene crystals, similar to Kilauea lavas. Proportions of plagioclase crystals and flow morphologies are consistent with predictions that groundmass crystal morphology plays a significant role in the development of crystal networks and yield strength, which instigates the development of a'a flow morphology (2, 3). Galapagos volcanoes tend to have more a'a than their Hawaiian counterparts Mauna Loa and Kilauea. Volcano slopes do not appear to control the proportion of each flow type (4); rather, abundance of groundmass plagioclase appears to be the distinguishing factor. An important distinction between the two systems is that Galapagos lavas have consistently higher Al2O3 content than Hawaiian volcanoes. High Al203 results in a comparatively high abundance of groundmass plagioclase, and may partly explain the prevalence of a'a. We note that while the relative abundance of a'a and pahoehoe flow morphologies on other volcanoes is rarely quantified, Mount Etna is also distinguished by abundant

  8. First record of a spawning aggregation for the tropical eastern Pacific endemic grouper Mycteroperca olfax in the Galapagos Marine Reserve.

    PubMed

    Salinas-de-León, P; Rastoin, E; Acuña-Marrero, D

    2015-07-01

    This study provides direct and indirect evidence of temporally and spatially consistent spawning aggregations for the grouper Mycteroperca olfax. Recently reported declines in population numbers, probably related to the direct targeting of aggregations by artisanal fishermen, highlight the urgent need for species-specific management actions in the Galapagos Marine Reserve, such as minimum and maximum landing sizes, and the importance of protecting key aggregation sites with the declaration of no-take areas and the establishment of total fishing bans during the reproductive season.

  9. Isolation and characterization of 10 polymorphic microsatellite loci for the endangered Galapagos-endemic whitespotted sandbass (Paralabrax albomaculatus).

    PubMed

    Bertolotti, Alicia C; Griffiths, Sarah M; Truelove, Nathan K; Box, Stephen J; Preziosi, Richard F; Salinas de Leon, Pelayo

    2015-01-01

    The white-spotted sandbass (Paralabrax albomaculatus) is a commercially important species in the Galapagos Marine Reserve, but is classified as endangered in the IUCN Red List. For this study, 10 microsatellite loci were isolated and characterized using Illumina paired-end sequencing. These loci can be used for genetic studies of population structure and connectivity to aid in the management of the white-spotted sandbass and other closely-related species. The 10 characterized loci were polymorphic, with 11-49 alleles per locus, and observed heterozygosity ranged from 0.575 to 0.964. This set of markers is the first to be developed for this species.

  10. Demographic Outcomes and Ecosystem Implications of Giant Tortoise Reintroduction to Española Island, Galapagos

    PubMed Central

    Gibbs, James P.; Hunter, Elizabeth A.; Shoemaker, Kevin T.; Tapia, Washington H.; Cayot, Linda J.

    2014-01-01

    Restoration of extirpated species via captive breeding has typically relied on population viability as the primary criterion for evaluating success. This criterion is inadequate when species reintroduction is undertaken to restore ecological functions and interactions. Herein we report on the demographic and ecological outcomes of a five-decade-long population restoration program for a critically endangered species of “ecosystem engineer”: the endemic Española giant Galapagos tortoise (Chelonoidis hoodensis). Our analysis of complementary datasets on tortoise demography and movement, tortoise-plant interactions and Española Island’s vegetation history indicated that the repatriated tortoise population is secure from a strictly demographic perspective: about half of tortoises released on the island since 1975 were still alive in 2007, in situ reproduction is now significant, and future extinction risk is low with or without continued repatriation. Declining survival rates, somatic growth rates, and body condition of repatriates suggests, however, that resources for continued population growth are increasingly limited. Soil stable carbon isotope analyses indicated a pronounced shift toward woody plants in the recent history of the island’s plant community, likely a legacy of changes in competitive relations between woody and herbaceous plants induced by now-eradicated feral goats and prolonged absence of tortoises. Woody plants are of concern because they block tortoise movement and hinder recruitment of cactus–a critical resource for tortoises. Tortoises restrict themselves to remnant cactus patches and areas of low woody plant density in the center of the island despite an apparent capacity to colonize a far greater range, likely because of a lack of cactus elsewhere on the island. We conclude that ecosystem-level criteria for success of species reintroduction efforts take much longer to achieve than population-level criteria; moreover, reinstatement of

  11. ALVIN investigation of an active propagating rift system, Galapagos 95.5° W

    USGS Publications Warehouse

    Hey, R.N.; Sinton, J.M.; Kleinrock, M.C.; Yonover, R.N.; MacDonald, K.C.; Miller, S.P.; Searle, R.C.; Christie, D.M.; Atwater, T.M.; Sleep, N.H.; Johnson, H. Paul; Neal, C.A.

    1992-01-01

    ALVIN investigations have defined the fine-scale structural and volcanic patterns produced by active rift and spreading center propagation and failure near 95.5° W on the Galapagos spreading center. Behind the initial lithospheric rifting, which is propagating nearly due west at about 50 km m.y.−1, a triangular block of preexisting lithosphere is being stretched and fractured, with some recent volcanism along curving fissures. A well-organized seafloor spreading center, an extensively faulted and fissured volcanic ridge, develops ~ 10 km (~ 200,000 years) behind the tectonic rift tip. Regional variations in the chemical compositions of the youngest lavas collected during this program contrast with those encompassing the entire 3 m.y. of propagation history for this region. A maximum in degree of magmatic differentiation occurs about 9 km behind the propagating rift tip, in a region of diffuse rifting. The propagating spreading center shows a gentle gradient in magmatic differentiation culminating at the SW-curving spreading center tip. Except for the doomed rift, which is in a constructional phase, tectonic activity also dominates over volcanic activity along the failing spreading system. In contrast to the propagating rift, failing rift lavas show a highly restricted range of compositions consistent with derivation from a declining upwelling zone accompanying rift failure. The lithosphere transferred from the Cocos to the Nazca plate by this propagator is extensively faulted and characterized by ubiquitous talus in one of the most tectonically disrupted areas of seafloor known. The pseudofault scarps, where the preexisting lithosphere was rifted apart, appear to include both normal and propagator lavas and are thus more lithologically complex than previously thought. Biological communities, probably vestimentiferan tubeworms, occur near the top of the outer pseudofault scarp, although no hydrothermal venting was observed.

  12. Sedimentologic succession of uplifted coral community, Urvina Bay, Isabela Island, Galapagos Archipelago, Ecuador

    SciTech Connect

    Colgan, M.W.; Hollander, D.

    1987-05-01

    In March 1954, along the west-central coast of Isabela Island, an upward movement of magma suddenly raised Urvina Bay over 6 m and exposed several square kilometers of carbonate deposits covering a young aa lava flow (around 1000 years old). Results from 6 transect lines across the uplift, 30 cores, and 10 trenches describe the sedimentologic and ecologic transition from barren basalt to diverse carbonate sediments with small coral reefs. Along horizontal transects spanning from 0 to 7 m paleowater depth, there is a seaward progression from beaches, mangroves, and basalt to thick deposits (> 1.6 m) of carbonate sands and small coral reefs. Variation in water depth, degree of wave exposure, and irregularity of the aa lava topography provided many microhabitats where coral, calcareous algae, and mollusks settled and grew. Eight hermatypic coral species are found throughout the shelf, and three species (i.e., Pavona clavus, Pocillopora damicornis, and Porites lobata) produced five small, isolated, monospecific, coral-reef frameworks. The vertical section seen in cores and trenches shows that calcium carbonate increased upward, whereas volcanic sediments decreased; however, episodic layers occur with high concentrations of basaltic sands. In vertical samples from the central portion of the shelf, the coral population changed from small, isolated colonies of Psammocora (Plesioseris) superficalis near the basalt basement to large reef-forming colonies of Pocillopora damicornis farther upsection. Reefs of the Galapagos Islands are small and less diverse than most Pacific reefs. Nonetheless, understanding their temporal successional development should throw light on the origin and history of larger oceanic reefs in the Pacific.

  13. Demographic outcomes and ecosystem implications of giant tortoise reintroduction to Española Island, Galapagos.

    PubMed

    Gibbs, James P; Hunter, Elizabeth A; Shoemaker, Kevin T; Tapia, Washington H; Cayot, Linda J

    2014-01-01

    Restoration of extirpated species via captive breeding has typically relied on population viability as the primary criterion for evaluating success. This criterion is inadequate when species reintroduction is undertaken to restore ecological functions and interactions. Herein we report on the demographic and ecological outcomes of a five-decade-long population restoration program for a critically endangered species of "ecosystem engineer": the endemic Española giant Galapagos tortoise (Chelonoidis hoodensis). Our analysis of complementary datasets on tortoise demography and movement, tortoise-plant interactions and Española Island's vegetation history indicated that the repatriated tortoise population is secure from a strictly demographic perspective: about half of tortoises released on the island since 1975 were still alive in 2007, in situ reproduction is now significant, and future extinction risk is low with or without continued repatriation. Declining survival rates, somatic growth rates, and body condition of repatriates suggests, however, that resources for continued population growth are increasingly limited. Soil stable carbon isotope analyses indicated a pronounced shift toward woody plants in the recent history of the island's plant community, likely a legacy of changes in competitive relations between woody and herbaceous plants induced by now-eradicated feral goats and prolonged absence of tortoises. Woody plants are of concern because they block tortoise movement and hinder recruitment of cactus--a critical resource for tortoises. Tortoises restrict themselves to remnant cactus patches and areas of low woody plant density in the center of the island despite an apparent capacity to colonize a far greater range, likely because of a lack of cactus elsewhere on the island. We conclude that ecosystem-level criteria for success of species reintroduction efforts take much longer to achieve than population-level criteria; moreover, reinstatement of

  14. Demographic outcomes and ecosystem implications of giant tortoise reintroduction to Española Island, Galapagos.

    PubMed

    Gibbs, James P; Hunter, Elizabeth A; Shoemaker, Kevin T; Tapia, Washington H; Cayot, Linda J

    2014-01-01

    Restoration of extirpated species via captive breeding has typically relied on population viability as the primary criterion for evaluating success. This criterion is inadequate when species reintroduction is undertaken to restore ecological functions and interactions. Herein we report on the demographic and ecological outcomes of a five-decade-long population restoration program for a critically endangered species of "ecosystem engineer": the endemic Española giant Galapagos tortoise (Chelonoidis hoodensis). Our analysis of complementary datasets on tortoise demography and movement, tortoise-plant interactions and Española Island's vegetation history indicated that the repatriated tortoise population is secure from a strictly demographic perspective: about half of tortoises released on the island since 1975 were still alive in 2007, in situ reproduction is now significant, and future extinction risk is low with or without continued repatriation. Declining survival rates, somatic growth rates, and body condition of repatriates suggests, however, that resources for continued population growth are increasingly limited. Soil stable carbon isotope analyses indicated a pronounced shift toward woody plants in the recent history of the island's plant community, likely a legacy of changes in competitive relations between woody and herbaceous plants induced by now-eradicated feral goats and prolonged absence of tortoises. Woody plants are of concern because they block tortoise movement and hinder recruitment of cactus--a critical resource for tortoises. Tortoises restrict themselves to remnant cactus patches and areas of low woody plant density in the center of the island despite an apparent capacity to colonize a far greater range, likely because of a lack of cactus elsewhere on the island. We conclude that ecosystem-level criteria for success of species reintroduction efforts take much longer to achieve than population-level criteria; moreover, reinstatement of

  15. Seasonal shifts in body temperature and use of microhabitats by Galapagos land iguanas (Conolophus pallidus)

    SciTech Connect

    Christian, K.; Tracy, C.R.; Porter, W.P.

    1983-06-01

    Seasonal differences in the body temperatures (T/sub b/) of free-ranging Galapagos land iguanas (Conolophus pallidus) were detected by temperature sensitive telemetry transmitters. Midday T/sub b/'s of iguanas average 4.4/sup 0/C lower in the Garua (cool) season than in the Hot season. Measured T/sub b/'s and those predicted from biophysical models permitted the following conclusions: (1) lower T/sub b/'s during the Garua season represent an active shift in thermoregulation by the iguanas rather than a passive result of a cooler season; (2) the average midday T/sub b/ selected by the iguanas in either season is the T/sub b/ that allows maintenance of a constant T/sub b/ for the longest possible portion of the day; (3) by exploiting the warmer microclimate created by a cliff face, the iguanas are able to maintain a constant T/sub b/ for a full hour longer than they could elsewhere in their home range. Census data demonstrated that the iguanas exploited the warmer microclimate created by the cliff extensively during the Garua season, and the cliff face was visited by the iguanas relatively infrequently during the Hot season. Thus, the exploitation of the microclimate created by the cliff results in seasonal differences in the pattern of space utilization within the home ranges of the iguanas. Within the Garua season the iguanas moved away from the cliff more often on sunny days than during cloudy days. It is concluded that the physical environment is an important determinant of patterns of space utilization both within and between seasons.

  16. Is preference a predictor of enrichment efficacy in Galapagos tortoises (Chelonoidis nigra)?

    PubMed

    Mehrkam, Lindsay R; Dorey, Nicole R

    2014-01-01

    It is widely acknowledged that environmental enrichment plays an important role in promoting the welfare of captive animals. However, a topic of debate is whether an animal's preference for an enrichment strategy is any indicator of its efficacy. In addition, relatively few studies have evaluated environmental enrichment strategies for non-mammalian species. In the present study, we compared the results of an observational evaluation of enrichment efficacy with the results of a paired-stimulus preference assessment for three Galapagos tortoises. In the observational study, object enrichment (boomer balls and a free-flowing sprinkler) and keeper interactions (shell scrubbing and neck rubbing) were evaluated systematically for their effects on locomotion, species-typical behavior, aggressive and non-aggressive conspecific interactions, and enclosure. Preference assessments were subsequently conducted in which subjects could choose the enrichment strategy to be implemented. All subjects preferred keeper interactions consistently over object enrichment. Our results suggest that enrichment preference was a variable predictor of efficacy across enrichment species-typical behavior, activity levels, enclosure use, and aggressive and non-aggressive conspecific interactions strategies. Preference predicted efficacy for promoting species-typical behavior (1/3 subjects), activity levels (2/3 subjects), and enclosure use (2/3 subjects), but not conspecific interactions (0/3 subjects). The results suggest that preference may be an efficient predictor of enrichment efficacy when daily observational evaluations are not practical; however, the predictive utility of preference assessments may depend on the behavioral goal of the enrichment strategy. We discuss the need for future research examining the relationship between preference and enrichment efficacy-as well as other potential indicators of enrichment effectiveness-in captive animals. PMID:25065472

  17. Is preference a predictor of enrichment efficacy in Galapagos tortoises (Chelonoidis nigra)?

    PubMed

    Mehrkam, Lindsay R; Dorey, Nicole R

    2014-01-01

    It is widely acknowledged that environmental enrichment plays an important role in promoting the welfare of captive animals. However, a topic of debate is whether an animal's preference for an enrichment strategy is any indicator of its efficacy. In addition, relatively few studies have evaluated environmental enrichment strategies for non-mammalian species. In the present study, we compared the results of an observational evaluation of enrichment efficacy with the results of a paired-stimulus preference assessment for three Galapagos tortoises. In the observational study, object enrichment (boomer balls and a free-flowing sprinkler) and keeper interactions (shell scrubbing and neck rubbing) were evaluated systematically for their effects on locomotion, species-typical behavior, aggressive and non-aggressive conspecific interactions, and enclosure. Preference assessments were subsequently conducted in which subjects could choose the enrichment strategy to be implemented. All subjects preferred keeper interactions consistently over object enrichment. Our results suggest that enrichment preference was a variable predictor of efficacy across enrichment species-typical behavior, activity levels, enclosure use, and aggressive and non-aggressive conspecific interactions strategies. Preference predicted efficacy for promoting species-typical behavior (1/3 subjects), activity levels (2/3 subjects), and enclosure use (2/3 subjects), but not conspecific interactions (0/3 subjects). The results suggest that preference may be an efficient predictor of enrichment efficacy when daily observational evaluations are not practical; however, the predictive utility of preference assessments may depend on the behavioral goal of the enrichment strategy. We discuss the need for future research examining the relationship between preference and enrichment efficacy-as well as other potential indicators of enrichment effectiveness-in captive animals.

  18. Non-neutral evolution and reciprocal monophyly of two expressed Mhc class II B genes in Leach's storm-petrel.

    PubMed

    Dearborn, Donald C; Gager, Andrea B; Gilmour, Morgan E; McArthur, Andrew G; Hinerfeld, Douglas A; Mauck, Robert A

    2015-02-01

    The major histocompatibility complex (Mhc) is subject to pathogen-mediated balancing selection and can link natural selection with mate choice. We characterized two Mhc class II B loci in Leach's storm-petrel, Oceanodroma leucorhoa, focusing on exon 2 which encodes the portion of the protein that binds pathogen peptides. We amplified and sequenced exon 2 with locus-specific nested PCR and Illumina MiSeq using individually barcoded primers. Repeat genotyping of 78 single-locus genotypes produced identical results in 77 cases (98.7%). Sequencing of messenger RNA (mRNA) from three birds confirmed expression of both loci, consistent with the observed absence of stop codons or frameshifts in all alleles. In 48 birds, we found 9 and 12 alleles at the two loci, respectively, and all 21 alleles translated to unique amino acid sequences. Unlike many studies of duplicated Mhc genes, alleles of the two loci clustered into monophyletic groups. Consistent with this phylogenetic result, interlocus gene conversion appears to have affected only two short fragments of the exon. As predicted under a paradigm of pathogen-mediated selection, comparison of synonymous and non-synonymous substitution rates found evidence of a history of positive selection at putative peptide binding sites. Overall, the results suggest that the gene duplication event leading to these two loci is not recent and that point mutations and positive selection on the peptide binding sites may be the predominant forces acting on these genes. Characterization of these loci sets the stage for population-level work on the evolutionary ecology of Mhc in this species. PMID:25416539

  19. Phytoplankton Biomass Distribution and Identification of Productive Habitats Within the Galapagos Marine Reserve by MODIS, a Surface Acquisition System, and In-Situ Measurements

    EPA Science Inventory

    The Galapagos Marine Reserve (GMR) is one of the most diverse ecosystems in the world. Phytoplankton are the base of the ecosystem food chain for many higher trophic organisms, so identifying phytoplankton biomass distribution is the first step in understanding the dynamic envir...

  20. A comparative analysis of infiltration rates below a pasture and a secondary forest on Santa Cruz Island, Galapagos

    NASA Astrophysics Data System (ADS)

    d'Ozouville, N.; Pryet, A.; Tournebize, J.; Chaumont, C.; Gonzáles, A.; Dominguez, C.; Fuente-Tomai, P.; Fernandez, J.; Violette, S.

    2011-12-01

    The potential effects of land use changes on groundwater recharge are being investigated on the windward side of Santa Cruz Island, Galapagos. Comparative studies allow the identification of the processes (evaporation, transpiration, soil water storage) at the vegetation/soil interface leading to contrasting recharge rates under different land covers. During one year, we monitored soil water dynamics under two adjacent study plots differing only by their vegetation cover: a pasture and a secondary forest. Climatic variables were monitored above the pasture and completed by throughfall monitoring under the forest. Tensiometers provide a direct measurement of the driving force of water dynamics in the soil: the hydraulic head gradient. In the two plots, tensiometers were set up in vertical profiles together with soil water content probes and connected to an automatic acquisition device. The forest stand has a higher canopy storage capacity and aerodynamic resistance, which causes evaporation losses to be higher. This is confirmed by throughfall measurements: only ca. 80% of gross precipitation reaches the ground. Expectedly, soil water tension profiles present clearly different behaviors in the pasture and in the forest. Despite high uncertainties on estimated recharge rates, we show that parallel monitoring of soil hydrodynamics in these two study plots provides valuable insights and may help to manage or anticipate the potential effect of deforestation or invasion by introduced plants on the hydrology of Santa Cruz Island, Galapagos.

  1. Elucidating Native and Non-Native Plant-Fog Interactions Across Microclimatic Zones in San Cristobal Island, Galapagos

    NASA Astrophysics Data System (ADS)

    Schmitt, S.; Riveros-Iregui, D. A.; Hu, J.

    2015-12-01

    Changes in land use, such as the clear cutting of forests and the abandonment of land once used for agriculture, pose an incredible threat to the fragile ecosystems in the tropics. One such consequence of land use change in the tropics is the propagation of invasive plant species. The Galapagos Islands, an ecosystem subject to significant anthropogenic pressure by both increasing tourism and a growing native population, are especially threatened by invasive plant species. More than 800 plant species have been introduced in Galapagos, comprising over 60% of the total flora. San Cristobal Island in particular has been impacted by the introduction of non-native species; the combined pressures of invasive species and land use change have fundamentally altered 70% of the landscape of the island. We performed stable isotope analysis of fog water, surface water and plant xylem water to examine water use by both native and invasive plant species across different microclimatic zones. We conducted these measurements starting at the end of the rainy season and through the middle of the dry season. Our results represent an initial effort to characterize the effects of a changing vegetative cover on the water cycling of tropical islands and provide insight into the interactions between plants, surface water and groundwater at various spatial and temporal scales.

  2. Microanalysis of metals in barbs of a snow petrel (Pagodroma Nivea) from the Antarctica using synchrotron radiation X-ray fluorescence.

    PubMed

    Xie, Zhouqing; Zhang, Pengfei; Sun, Liguang; Xu, Siqi; Huang, Yuying; He, Wei

    2008-03-01

    For the first time synchrotron radiation X-ray fluorescence (SR-XRF) microanalysis was performed throughout the total length of 4 single barbs from the primaries and secondaries of a snow petrel (Pagodroma Nivea) collected in the Antarctica. Thirteen elements (S, Mg, K, Ca, Fe, Ni, Cu, Zn, Se, Sr, Ba, Hg and Pb) were detected somewhere in the barbs. Variations in levels of these elements within and among the barbs were obvious, indicating nonuniform microscale distributions. Factors influencing the fluctuations of the levels of the elements were investigated using a multivariate statistical analysis method. Five factors (F1 being associated with high loadings of Ca, Sr, and Ni, F2 with high loadings of Fe and Ba, F3 with high loadings of Se and Hg, F4 with high loadings of Ca and K, and F5 with high loadings of Zn and Pb) were found to explain about 80% of the total variance. Results from the factor analysis suggested external contamination of Fe, Ba, Pb, Zn and Hg on the feathers of the snow petrel. PMID:18191420

  3. Kauai endangered seabird study. Volume 1: Interactions of Dark-Rumped Petrels and Newell`s Shearwaters with utility structures on Kauai, Hawaii. Final report

    SciTech Connect

    Cooper, B.A.; Day, R.H.

    1995-12-01

    Declining populations of two endangered species of seabirds on Kauai, Hawaii--the Dark-Rumped Petrel and Newell`s Shearwater--have been the emphasis of a three-year research program to determine the causes of bird mortality and fallout and to recommend preventive measures. This study refined scientific understanding of the timing of bird movements, enabling future biologists to sample rates of avian traffic more efficiently and perhaps better identify the times when it would be most beneficial to reduce outdoor lighting, which has been linked to fallout. The study also identified three specific areas where collisions would be most beneficial. A sampling site was established in the highlands along a transmission line that runs from the south shore to the north shore through the interior and in proximity to several shearwater colonies. This site has provided a much clearer picture of Procellariiform behavior and collision mortality rates in the coastal areas. Volume 2 of this report describes the ecology of the Dark-Rumped Petrel and Newell`s Shearwater on the island of Kauai.

  4. Seafloor Hydrothermal Activity at the Galapagos Triple Junction, East Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Li, H.; Yu, Z.; Zhang, G.; Tao, C.; Chen, S.

    2014-12-01

    Since the first discovery of black smokers on the Gaplapgaos spreading center, over 500 hydrothermal sites have been confirmed on the mid-ocean ridge, arc and back-arc settings (Beaulieu et al., 2013). However, the hydrothermal activity at triple-junction has not received much attention. Consequently, there are outstanding questions regarding the features of the hydrothermal system, and the effect of the hydrothermal circulation on the tectonic activity of the triple-junction. In 2009, the Chinese Dayang Cruise 21 discovered the Precious Stone field (PSF) on the Dietz Semount at the southern flank of the Galapagos triple junction (GTJ). Most studies of the GTJ focus on the topographictectonic and stresssimulation, which suggest that the GTJ had complex evoluation(Smith et al., 2011, 2013; Mitchell et al., 2011,Schouten et al., 2012). Water anomay were clear detected and samples of hydrothermal deposit and rocks were collected by TV-Grab (Figure.1). This study aims to understand the geological features of the PSF related hydrothermal activity. Hydrothermal mineralization Three types of sedimentary hydrothermal deposits representing three different hydrothermal activity stages (Figure 1)are confirmed in the PSF: 1) sediments with native sulfur and pyrite clasts(Type I), 2) Fe—Mn oxides (Type II), and 3) clay minerals mainlynontronite(Type III). Type II sedimentsprecipitate early and the source comprises of clasts of distal hydrothermal plume. The nontronite-rich sediments propably derive from the low-temperature alteration of Fe—Mn oxides. Type 1 sediments are found on the active hydrothermal venting field. Hydrothermal plume Water anomaly were detected at the southewestern PSF. We observed widespreadsedimentary hydrothermal depositsin the western PSF, but no water anomaly. According to the results of five water anomaly dectection lines, we predicted the existence of three hydrothermal vents in the PSF. Seafloor type inversion Multi-beam backscatter data were

  5. The September 1988 intracaldera avalanche and eruption at Fernandina volcano, Galapagos Islands

    USGS Publications Warehouse

    Chadwick, W.W.; De Roy, T.; Carrasco, A.

    1991-01-01

    During 14-16 September 1988, a large intracaldera avalanche and an eruption of basaltic tephra and lava at Fernandina volcano, Galapagos, produced the most profound changes within the caldera since its collapse in 1968. A swarm of eight earthquakes (mb 4.7-5.5) occurred in a 14 h period on 24 February 1988 at Fernandina, and two more earthquakes of this size followed on 15 April and 20 May, respectively. On 14 September 1988, another earthquake (mb 4.6) preceded a complex series of events. A debris avalanche was generated by the failure of a fault-bounded segment of the east caldera wall, approximately 2 km long and 300 m wide. The avalanche deposit is up to 250 m thick and has an approximate volume of 0.9 km3. The avalanche rapidly displaced a preexisting lake from the southeast end of the caldera floor to the northwest end, where the water washed up against the lower part of the caldera wall, then gradually seeped into the avalanche deposit and was completely gone by mid-January 1989. An eruption began in the caldera within about 1-2 h of the earthquake, producing a vigorous tephra plume for about 12 h, then lava flows during the next two days. The eruption ended late on 16 September. Most of the eruptive activity was from vents on the caldera floor near the base of the new avalanche scar. Unequivocal relative timing of events is difficult to determine, but seismic records suggest that the avalanche may have occurred 1.6 h after the earthquake, and field relations show that lava was clearly erupted after the avalanche was emplaced. The most likely sequence of events seems to be that the 1988 feeder dike intruded upward into the east caldera wall, dislocated the unstable wall block, and triggered the avalanche. The avalanche immediately exposed the newly emplaced dike and initiated the eruption. The exact cause of the earthquakes is unknown. ?? 1991 Springer-Verlag.

  6. Microbial Populations in Extreme Environments: Investigations and Characterizations of the Microbiology and Geochemistry of Galapagos Island Fumaroles

    NASA Astrophysics Data System (ADS)

    Mayhew, L. E.; Childers, S. E.; Geist, D.

    2005-12-01

    The extreme physiochemical conditions, insularity, and wide range in ages of fumaroles of the Galapagos Islands provide an excellent opportunity to explore for novel microorganisms and to study life in extreme environments. This is the first study that measures microbial diversity of Galapagos fumaroles. Forty-seven samples were collected from six distinct fumarole fields on Sierra Negra and Alcedo volcanoes. Vulcan Chico, on Sierra Negra, was activated during the last eruption in 1979. Two of the other fumarole fields on Sierra Negra are associated with a long-lived fault system on the caldera floor and are therefore likely to be significantly older. The fault-associated fumaroles have widespread alteration haloes (up to 100 m in diameter) and thick deposits of native sulfur. The most vigorous of the fumarole fields on Alcedo activated in late 1993 to early 1994. The second fumarole field on Alcedo is associated with a recently extinct geyser and the third is located on a rhyolite vent. A diversity of colors was observed in the substrates at all of the fumarole fields and some may be the result of microbial activity. Collection sites were chosen on the basis of temperature and the variations in the substrate in order to obtain samples from a variety of environments. Temperatures at sample sites range from 25.0 to 178.5° C, and pH from 0 to 6. The material collected varies between sites and includes crystalline sulfur deposits, clay, sandy and rocky soils, and microbial mats. Substrate material is characterized by powder x-ray diffractometry and scanning electron microscopy and gases collected from five of the fumarole fields are being analyzed to test for chemical controls on the microbial populations. Genomic DNA is being extracted from all of the samples. Primers for Bacteria and Archaea are used for PCR amplification of the 16S rRNA gene. To date, 22 of 37 processed samples have amplifiable DNA. Microbial diversity of samples possessing amplifiable DNA is

  7. The Bolivar Channel Ecosystem of the Galapagos Marine Reserve: Energy flow structure and role of keystone groups

    NASA Astrophysics Data System (ADS)

    Ruiz, Diego J.; Wolff, Matthias

    2011-08-01

    The Bolivar Channel Ecosystem (BCE) is among the most productive zones in the Galapagos Marine Reserve (GMR). It is exposed to relatively cool, nutrient-rich waters of the Cromwell current, which are brought to the photic zone through topographic upwelling. The BCE is characterized by a heterogeneous rocky reef habitat covered by dense algae beds and inhabited by numerous invertebrate and fish species, which represent the food for higher predators including seals and sharks and exploited fish species. In addition, plankton and detritus based food chains channel large amounts of energy through the complex food web. Important emblematic species of the Galapagos archipelagos reside in this area such as the flightless cormorant, the Galapagos penguin and the marine iguanas. A trophic model of BCE was constructed for the habitats < 30 m depth that fringe the west coast of Isabela and east coast of Fernandina islands covering 14% of the total BCE area (44 km 2). The model integrates data sets from sub tidal ecological monitoring and marine vertebrate population monitoring (2004 to 2008) programs of the Charles Darwin Foundation and consists of 30 compartments, which are trophically linked through a diet matrix. Results reveal that the BCE is a large system in terms of flows (38 695 t km - 2 yr - 1 ) comparable to Peruvian Bay Systems of the Humboldt upwelling system. A very large proportion of energy flows from the primary producers (phytoplankton and macro-algae) to the second level and to the detritus pool. Catches are high (54.3 t km - 2 yr - 1 ) and are mainly derived from the second and third trophic levels (mean TL of catch = 2.45) making the fisheries gross efficiency high (0.3%). The system's degree of development seems rather low as indicated by a P/R ratio of 4.19, a low ascendency (37.4%) and a very low Finn's cycling index (1.29%). This is explained by the system's exposure to irregular changes in oceanographic conditions as related to the EL Niño Southern

  8. The Oxidation State of Fe in Glasses from the Galapagos Archipelago: Variable Oxygen Fugacity as a Function of Mantle Source

    NASA Astrophysics Data System (ADS)

    Peterson, M. E.; Kelley, K. A.; Cottrell, E.; Saal, A. E.; Kurz, M. D.

    2015-12-01

    The oxidation state of the mantle plays an intrinsic role in the magmatic evolution of the Earth. Here we present new μ-XANES measurements of Fe3+/ΣFe ratios (a proxy for ƒO2) in a suite of submarine glasses from the Galapagos Archipelago. Using previously presented major, trace, and volatile elements and isotopic data for 4 groups of glass that come from distinct mantle sources (depleted upper mantle, 2 recycled, and a primitive mantle source) we show that Fe3+/ΣFe ratios vary both with the influence of shallow level processes and with variations in mantle source. Fe3+/ΣFe ratios increase with differentiation (i.e. decreasing MgO), but show a large variation at a given MgO. Progressive degassing of sulfur accompanies decreasing Fe3+/ΣFe ratios, while assimilation of hydrothermally altered crust (as indicated by increasing Sr/Sr*) is shown to increase Fe3+/ΣFe ratios. After taking these processes into account, there is still variability in the Fe3+/ΣFe ratios of the isotopically distinct sample suites studied, yielding a magmatic ƒO2 that ranges from ΔQFM = +0.16 to +0.74 (error < 0.5 log units) and showing that oxidation state varies as a function of mantle source composition in the Galapagos hotspot system. After correcting back to a common MgO content = 8.0 wt%, the trace element depleted group similar to MORB (ITD), and the group similar to Pinta (WD = high Th/La, Δ7/4, Δ8/4 ratios) show Fe3+/ΣFe ratios within the range of MORB (average ITD = 0.162 ± 0.003 and WD = 0.164 ± 0.006). Another trace element enriched group similar to Sierra Negra and Cerro Azul (ITE = enriched Sr and Pb isotopes) shows evidence of mixing between oxidized and reduced sources (ITE oxidized end-member = 0.177). This suggests that mantle sources in the Galapagos that are thought to contain recycled components (i.e., WD and ITE groups) have distinct oxidation states. The high 3He/4He Fernandina samples (HHe group) are shown to be the most oxidized (ave. 0.175 ± 0

  9. What factors drive prolactin and corticosterone responses to stress in a long-lived bird species (snow petrel Pagodroma nivea)?

    PubMed

    Angelier, Frédéric; Moe, Børge; Blanc, Samuel; Chastel, Olivier

    2009-01-01

    Life-history theory predicts that individuals should adapt their parental investment to the costs and benefits of the current reproductive effort. This could be achieved by modulating the hormonal stress response, which may shift energy investment away from reproduction and redirect it toward survival. In birds, this stress response consists of a release of corticosterone that may be accompanied by a decrease in circulating prolactin, a hormone involved in the regulation of parental care. We lack data on the modulation of the prolactin stress response. In this study, we tested the hypothesis that individuals should modulate their prolactin stress response according to the fitness value of the current reproductive effort relative to the fitness value of future reproduction. Specifically, we examined the influence of breeding status (failed breeders vs. incubating birds) and body condition on prolactin and corticosterone stress responses in a long-lived species, the snow petrel Pagodroma nivea. When facing stressors, incubating birds had higher prolactin levels than failed breeders. However, we found no effect of body condition on the prolactin stress response. The corticosterone stress response was modulated according to body condition but was not affected by breeding status. We also performed an experiment using injections of adrenocorticotropic hormone (ACTH) and found that the modulation of the corticosterone stress response was probably associated with a reduction in ACTH release by the pituitary and a decrease in adrenal sensitivity to ACTH. In addition, we examined whether prolactin and corticosterone secretion were functionally linked. We found that these two hormonal stress responses were not correlated. Moreover, injection of ACTH did not affect prolactin levels, demonstrating that short-term variations in prolactin levels are not governed directly or indirectly by ACTH release. Thus, we suggest that the corticosterone and prolactin responses to short

  10. Galapagos hotspot-spreading center system: 1. Spatial petrological and geochemical variations (83/sup 0/W-101/sup 0/W)

    SciTech Connect

    Schilling, J.; Kingsley, R.H.; Devine, J.D.

    1982-07-10

    We report on the petrology and geochemistry of basalts dredged at 40--50 km intervals along the Galapagos Spreading Center, between 83/sup 0/W and 101/sup 0/W (40 stations). Emphasis is on spatial variations of 'whole rock' major elements, rare earths, trace metals of the first transition series, and the nature of phenocryst assemblages and their abundances. These results provide new constraints on the nature and scale of mantle source heterogeneities, melting conditions, thermal field, and dynamics of crustal formation of the region. We suggest that ridge segments outside the high magnetic amplitude zone are at a steady state as a result of passive seafloor spreading. Basalts from these segments are apparently derived from an asthenosphere relatively uniformally depleted in incompatible elements, which appears of worldwide extent. We reject Vogt and DeBoer's (1976) model invoking damming at fracture zones of subaxial asthenosphere flow of crystal slushes and increasing fractional crystallization down the flow line, because this model would not explain the gradients in REE observed about the Galapagos Platform. Our preferred model combines the mantle-plume binary mixing model of Schilling (1973) with the concept of recurring rift propagation proposed by Hey (1977a). We further propose that pulsating mantle plume flux, perhaps in the form of a chain of blobs, may initiate the development of new rifts and their propagation. The present position of the tips of such new propagating rifts locate the wave fronts of such pulsating mantle plume flow. A two million year period is suggested for the last 4 m.y. from Wilson and Hey's (1979) information Rigorous testing of our preferred model is possible.

  11. So Long and Thanks for All the Fish: Overexploitation of the Regionally Endemic Galapagos Grouper Mycteroperca olfax (Jenyns, 1840)

    PubMed Central

    Friedlander, Alan M.; Koike, Haruko; Zimmerhackel, Johanna; Schuhbauer, Anna; Eddy, Tyler; Salinas-de-León, Pelayo

    2016-01-01

    The regionally endemic Galapagos Grouper, locally known as bacalao, is one of the most highly prized finfish species within the Galapagos Marine Reserve (GMR). Concerns of overfishing, coupled with a lack of fishing regulations aimed at this species raises concerns about the current population health. We assessed changes in population health over a 30-year period using three simple indicators: (1) percentage of fish below reproductive size (Lm); (2) percentage of fish within the optimum length interval (Lopt); and (3) percentage of mega-spawners in the catch. Over the assessed period, none of the indicators reached values associated with healthy populations, with all indicators declining over time. Furthermore, the most recent landings data show that the vast majority of the bacalao caught (95.7%,) were below Lm, the number of fish within the Lopt interval was extremely low (4.7%), and there were virtually no mega-spawners (0.2%). Bacalao fully recruit to the fishery 15 cm below the size at which 50% of the population matures. The Spawning Potential Ratio is currently 5% of potential unfished fecundity, strongly suggesting severe overfishing. Our results suggest the need for bacalao-specific management regulations that should include minimum (65 cm TL) and maximum (78 cm TL) landing sizes, slot limits (64–78 cm TL), as well as a closed season during spawning from October to January. It is recognized that these regulations are harsh and will certainly have negative impacts on the livelihoods of fishers in the short term, however, continued inaction will likely result in a collapse of this economically and culturally valuable species. Alternative sources of income should be developed in parallel with the establishment of fishing regulations to limit the socio-economic disruption to the fishing community during the transition to a more sustainable management regime. PMID:27780213

  12. Fine scale bio-physical oceanographic characteristics predict the foraging occurrence of contrasting seabird species; Gannet (Morus bassanus) and storm petrel (Hydrobates pelagicus)

    NASA Astrophysics Data System (ADS)

    Scott, B. E.; Webb, A.; Palmer, M. R.; Embling, C. B.; Sharples, J.

    2013-10-01

    As we begin to manage our oceans in much more spatial detail we must understand a great deal more about oceanographic habitat preferences of marine mobile top predators. In this unique field study we test a hypothesis on the mechanisms defining mobile predator foraging habitat characteristics by comparing temporally and spatially detailed bio-physical oceanographic data from contrasting topographical locations. We contrast the foraging locations of two very different seabird species, gannets and storm petrels, by repeatedly sampling a bank and a nearby flat area over daily tidal cycles during spring and neap tides. The results suggest that storm petrels are linked to foraging in specific locations where internal waves are produced, which is mainly on banks. These locations can also include the presence of high biomass of chlorophyll. In contrast, the location where more gannets are foraging is significantly influenced by temporal variables with higher densities of foraging birds much more likely during the neap tide than times of spring tide. The foraging times of both species was influenced by differences between the vertical layers of the water column above and below the thermocline; via either vertical shear of horizontal currents or absolute differences in speed between layers. Higher densities of foraging gannets were significantly more likely to be found at ebb tides in both bank and flat regions however over the bank, the density of foraging gannets was higher when the differences in speed between the layers were at a maximum. Both gannets and storm petrels appear to be more likely to forage when wind direction is opposed to tidal direction. This detailed understanding links foraging behaviour to predictable spatial and temporal bio-physical vertical characteristics and thus can be immediately used to explain variance and increase certainty in past abundance and distributional surveys. These results also illuminate the types of variables that should be

  13. Young segment-scale eruption discovered on the eastern Galapagos rift during the GALREX 2011 Expedition

    NASA Astrophysics Data System (ADS)

    Embley, R. W.; White, S. M.; Hammond, S. R.; McClinton, J. T.; Rex, C.

    2011-12-01

    New high resolution mapping with an EM302 multibeam system and seafloor observations made with the Little Hercules remotely operated vehicle (ROV) during the July 2011 GALREX expedition have discovered a very recent eruption along Segment III (Christie et al., 2005) centered at 88 deg 19.5'W on the eastern Galapagos spreading center (GSC). The site was chosen for detailed study after a water column survey using a towed CTD package identified intense particle plumes rising up to 250m above seafloor along the entire segment (see abstracts by Baker et al. and Holden et al., this meeting). The segment is characterized by ridge-and-valley terrain with the most recent neovolcanic ridge extending, respectively, 25 km west and 20 km east of a central low-relief area that is quasi-circular, ~2 km radius, less than 30 m high. The neovolcanic ridge, revealed by the EM302 bathymetry to be a generally hummocky edifice less than 1 km wide and under ~40 m high, is cut by a very small axial graben barely resolved in the EM302 bathymetry. Two areas were surveyed during five ROV dives, four on the central area near 88 deg 18.5'W and one dive at 14 km east at 88 deg 10.8'W. A third high intensity plume target near the western extremity of the segment at 88 deg 27.2'W was not investigated using the ROV. The recent lobate and pillow lava flows were emplaced in narrow grabens along and adjacent to the neovolcanic ridge. In several places, the flow was observed to fill the axial graben. It is likely that the flow thickness ranges from meters to 10's of meters, depending upon the pre-eruption graben size and local effusion variations. However, no long, channel-fed lava flows were found. Flow boundaries based on preliminary ROV navigation average less than 100 meters across-axis. The lobate lavas all had a very similar glassy appearance and negligible sediment cover, making them easy to recognize amid the surrounding, older flows. The age of these lavas appeared visually younger than the

  14. Fowl play and the price of petrel: long-living Procellariiformes have peroxidation-resistant membrane composition compared with short-living Galliformes.

    PubMed

    Buttemer, William A; Battam, Harry; Hulbert, A J

    2008-08-23

    The membrane pacemaker hypothesis predicts that long-living species will have more peroxidation-resistant membrane lipids than shorter living species. We tested this hypothesis by comparing the fatty acid composition of heart phospholipids from long-living Procellariiformes (petrels and albatrosses) to those of shorter living Galliformes (fowl). The seabirds were obtained from by-catch of commercial fishing operations and the fowl values from published data. The 3.8-fold greater predicted longevity of the seabirds was associated with elevated content of peroxidation-resistant monounsaturates and reduced content of peroxidation-prone polyunsaturates and, consequently, a significantly reduced peroxidation index in heart membrane lipids, compared with fowl. Peroxidation-resistant membrane composition may be an important physiological trait for longevous species. PMID:18492647

  15. Philopatry drives genetic differentiation in an island archipelago: comparative population genetics of Galapagos Nazca boobies (Sula granti) and great frigatebirds (Fregata minor).

    PubMed

    Levin, Iris I; Parker, Patricia G

    2012-11-01

    Seabirds are considered highly mobile, able to fly great distances with few apparent barriers to dispersal. However, it is often the case that seabird populations exhibit strong population genetic structure despite their potential vagility. Here we show that Galapagos Nazca booby (Sula granti) populations are substantially differentiated, even within the small geographic scale of this archipelago. On the other hand, Galapagos great frigatebird (Fregata minor) populations do not show any genetic structure. We characterized the genetic differentiation by sampling five colonies of both species in the Galapagos archipelago and analyzing eight microsatellite loci and three mitochondrial genes. Using an F-statistic approach on the multilocus data, we found significant differentiation between nearly all island pairs of Nazca booby populations and a Bayesian clustering analysis provided support for three distinct genetic clusters. Mitochondrial DNA showed less differentiation of Nazca booby colonies; only Nazca boobies from the island of Darwin were significantly differentiated from individuals throughout the rest of the archipelago. Great frigatebird populations showed little to no evidence for genetic differentiation at the same scale. Only two island pairs (Darwin - Wolf, N. Seymour - Wolf) were significantly differentiated using the multilocus data, and only two island pairs had statistically significant φ(ST) values (N. Seymour - Darwin, N. Seymour - Wolf) according to the mitochondrial data. There was no significant pattern of isolation by distance for either species calculated using both markers. Seven of the ten Nazca booby migration rates calculated between island pairs were in the south or southeast to north or northwest direction. The population differentiation found among Galapagos Nazca booby colonies, but not great frigatebird colonies, is most likely due to differences in natal and breeding philopatry.

  16. Philopatry drives genetic differentiation in an island archipelago: comparative population genetics of Galapagos Nazca boobies (Sula granti) and great frigatebirds (Fregata minor).

    PubMed

    Levin, Iris I; Parker, Patricia G

    2012-11-01

    Seabirds are considered highly mobile, able to fly great distances with few apparent barriers to dispersal. However, it is often the case that seabird populations exhibit strong population genetic structure despite their potential vagility. Here we show that Galapagos Nazca booby (Sula granti) populations are substantially differentiated, even within the small geographic scale of this archipelago. On the other hand, Galapagos great frigatebird (Fregata minor) populations do not show any genetic structure. We characterized the genetic differentiation by sampling five colonies of both species in the Galapagos archipelago and analyzing eight microsatellite loci and three mitochondrial genes. Using an F-statistic approach on the multilocus data, we found significant differentiation between nearly all island pairs of Nazca booby populations and a Bayesian clustering analysis provided support for three distinct genetic clusters. Mitochondrial DNA showed less differentiation of Nazca booby colonies; only Nazca boobies from the island of Darwin were significantly differentiated from individuals throughout the rest of the archipelago. Great frigatebird populations showed little to no evidence for genetic differentiation at the same scale. Only two island pairs (Darwin - Wolf, N. Seymour - Wolf) were significantly differentiated using the multilocus data, and only two island pairs had statistically significant φ(ST) values (N. Seymour - Darwin, N. Seymour - Wolf) according to the mitochondrial data. There was no significant pattern of isolation by distance for either species calculated using both markers. Seven of the ten Nazca booby migration rates calculated between island pairs were in the south or southeast to north or northwest direction. The population differentiation found among Galapagos Nazca booby colonies, but not great frigatebird colonies, is most likely due to differences in natal and breeding philopatry. PMID:23170212

  17. Philopatry drives genetic differentiation in an island archipelago: comparative population genetics of Galapagos Nazca boobies (Sula granti) and great frigatebirds (Fregata minor)

    PubMed Central

    Levin, Iris I; Parker, Patricia G

    2012-01-01

    Seabirds are considered highly mobile, able to fly great distances with few apparent barriers to dispersal. However, it is often the case that seabird populations exhibit strong population genetic structure despite their potential vagility. Here we show that Galapagos Nazca booby (Sula granti) populations are substantially differentiated, even within the small geographic scale of this archipelago. On the other hand, Galapagos great frigatebird (Fregata minor) populations do not show any genetic structure. We characterized the genetic differentiation by sampling five colonies of both species in the Galapagos archipelago and analyzing eight microsatellite loci and three mitochondrial genes. Using an F-statistic approach on the multilocus data, we found significant differentiation between nearly all island pairs of Nazca booby populations and a Bayesian clustering analysis provided support for three distinct genetic clusters. Mitochondrial DNA showed less differentiation of Nazca booby colonies; only Nazca boobies from the island of Darwin were significantly differentiated from individuals throughout the rest of the archipelago. Great frigatebird populations showed little to no evidence for genetic differentiation at the same scale. Only two island pairs (Darwin – Wolf, N. Seymour – Wolf) were significantly differentiated using the multilocus data, and only two island pairs had statistically significant φST values (N. Seymour – Darwin, N. Seymour – Wolf) according to the mitochondrial data. There was no significant pattern of isolation by distance for either species calculated using both markers. Seven of the ten Nazca booby migration rates calculated between island pairs were in the south or southeast to north or northwest direction. The population differentiation found among Galapagos Nazca booby colonies, but not great frigatebird colonies, is most likely due to differences in natal and breeding philopatry. PMID:23170212

  18. Pockmark development in the Petrel Sub-basin, Timor Sea, Northern Australia: Seabed habitat mapping in support of CO2 storage assessments

    NASA Astrophysics Data System (ADS)

    Nicholas, W. A.; Nichol, S. L.; Howard, F. J. F.; Picard, K.; Dulfer, H.; Radke, L. C.; Carroll, A. G.; Tran, M.; Siwabessy, P. J. W.

    2014-07-01

    The extent to which fluids may leak from sedimentary basins to the seabed is a critical issue for assessing the potential of a basin for carbon capture and storage. The Petrel Sub-basin, located beneath central and eastern Joseph Bonaparte Gulf in tropical northern Australia, was identified as potentially suitable for the geological storage of CO2 because of its geological characteristics and proximity to offshore gas and petroleum resources. In May 2012, a multidisciplinary marine survey (SOL5463) was undertaken to collect data in two targeted areas of the Petrel Sub-basin to facilitate an assessment of its CO2 storage potential. This paper focuses on Area 1 of that survey, a 471 km2 area of sediment-starved shelf (water depths of 78 to 102 m), characterised by low-gradient plains, low-lying ridges, palaeo-channels and shallow pockmarks. Three pockmark types are recognised: small shallow unit pockmarks 10-20 m in diameter (generally <1 m, rarely to 2 m deep), composite pockmarks of 150-300 m diameter formed from the co-location of several cross-cutting pockmarks forming a broad shallow depression (<1 m deep), and pockmark clusters comprised of shallow unit pockmarks co-located side by side (150-300 m width overall, <1 m deep). Pockmark distribution is non-random, focused within and adjacent to palaeo-channels, with pockmark clusters also located adjacent to ridges. Pockmark formation is constrained by AMS 14C dating of in situ mangrove deposits and shells to have begun after 15.5 cal ka BP when a rapid marine transgression of Bonaparte Shelf associated with meltwater pulse 1A drowned coastal mangrove environments. Pockmark development is likely an ongoing process driven by fluid seepage at the seabed, and sourced from CO2 produced in the shallow sub-surface (<2 m) sediment. No evidence for direct connection to deeper features was observed.

  19. Does short-term fasting lead to stressed-out parents? A study of incubation commitment and the hormonal stress responses and recoveries in snow petrels.

    PubMed

    Angelier, Frédéric; Wingfield, John C; Parenteau, Charline; Pellé, Marie; Chastel, Olivier

    2015-01-01

    The hormonal stress response is flexible and can be modulated by individuals according to its costs and benefits. Therefore, it is predicted that parents in poor body condition should modify their hormonal stress response, and thus, redirect energy allocation processes from parental care to self-maintenance when stressors occur. To test this prediction, most studies on free-living vertebrates have only focused on the stress response while the stress recovery - how quickly hormonal levels return to baseline values - has been neglected. Moreover, most studies have only focused on corticosterone - the primary mediator of allostasis - without paying attention to prolactin despite its major role in mediating parental behaviors. Here, we examined the effect of a short-term fasting event on the corticosterone and prolactin stress responses and recoveries, and we subsequently explored their relationships with parental decision in the snow petrel (Pagodroma nivea). By comparing the hormonal profiles of fasting and non-fasting snow petrels, we showed that parents modulate their corticosterone (but not prolactin) stress response according to their energetic status. We also described for the first time the hormonal stress recoveries in wild birds and found that they did not differ between fasting and non-fasting birds. Importantly, egg neglect was negatively correlated with circulating prolactin but not corticosterone levels in this species, demonstrating therefore a complex link between body condition, parental behavior and circulating corticosterone and prolactin levels. We suggest that both corticosterone and prolactin play a major role in the way parents adjust to stressors. This multiple signaling may allow parents to fine-tune their response to stressors, and especially, to activate specific allostasis-related mechanisms in a timely manner. PMID:25456104

  20. Does short-term fasting lead to stressed-out parents? A study of incubation commitment and the hormonal stress responses and recoveries in snow petrels.

    PubMed

    Angelier, Frédéric; Wingfield, John C; Parenteau, Charline; Pellé, Marie; Chastel, Olivier

    2015-01-01

    The hormonal stress response is flexible and can be modulated by individuals according to its costs and benefits. Therefore, it is predicted that parents in poor body condition should modify their hormonal stress response, and thus, redirect energy allocation processes from parental care to self-maintenance when stressors occur. To test this prediction, most studies on free-living vertebrates have only focused on the stress response while the stress recovery - how quickly hormonal levels return to baseline values - has been neglected. Moreover, most studies have only focused on corticosterone - the primary mediator of allostasis - without paying attention to prolactin despite its major role in mediating parental behaviors. Here, we examined the effect of a short-term fasting event on the corticosterone and prolactin stress responses and recoveries, and we subsequently explored their relationships with parental decision in the snow petrel (Pagodroma nivea). By comparing the hormonal profiles of fasting and non-fasting snow petrels, we showed that parents modulate their corticosterone (but not prolactin) stress response according to their energetic status. We also described for the first time the hormonal stress recoveries in wild birds and found that they did not differ between fasting and non-fasting birds. Importantly, egg neglect was negatively correlated with circulating prolactin but not corticosterone levels in this species, demonstrating therefore a complex link between body condition, parental behavior and circulating corticosterone and prolactin levels. We suggest that both corticosterone and prolactin play a major role in the way parents adjust to stressors. This multiple signaling may allow parents to fine-tune their response to stressors, and especially, to activate specific allostasis-related mechanisms in a timely manner.

  1. The dominance of introduced plant species in the diets of migratory Galapagos tortoises increases with elevation on a human-occupied island

    USGS Publications Warehouse

    Blake, Stephen; Guézou, Anne; Deem, Sharon L.; Yackulic, Charles B.; Cabrera, Fredy

    2015-01-01

    The distribution of resources and food selection are fundamental to the ecology, life history, physiology, population dynamics, and conservation of animals. Introduced plants are changing foraging dynamics of herbivores in many ecosystems often with unknown consequences. Galapagos tortoises, like many herbivores, undertake migrations along elevation gradients driven by variability in vegetation productivity which take them into upland areas dominated by introduced plants. We sought to characterize diet composition of two species of Galapagos tortoises, focussing on how the role of introduced forage species changes over space and the implications for tortoise conservation. We quantified the distribution of tortoises with elevation using GPS telemetry. Along the elevation gradient, we quantified the abundance of introduced and native plant species, estimated diet composition by recording foods consumed by tortoises, and assessed tortoise physical condition from body weights and blood parameter values. Tortoises ranged between 0 and 429 m in elevation over which they consumed at least 64 plant species from 26 families, 44 percent of which were introduced species. Cover of introduced species and the proportion of introduced species in tortoise diets increased with elevation. Introduced species were positively selected for by tortoises at all elevations. Tortoise physical condition was either consistent or increased with elevation at the least biologically productive season on Galapagos. Santa Cruz tortoises are generalist herbivores that have adapted their feeding behavior to consume many introduced plant species that has likely made a positive contribution to tortoise nutrition. Some transformed habitats that contain an abundance of introduced forage species are compatible with tortoise conservation.

  2. Chemical and isotopic diversity in basalts dredged from the East Pacific Rise at 10°S, the fossil Galapagos Rise and the Nazca plate

    USGS Publications Warehouse

    Batiza, Rodey; Oestrike, Richard; Futa, Kiyoto

    1982-01-01

    The dredges from the East Pacific Rise at about 10°S recovered unusual transitional, light rare-earth element (LREE) enriched basalts which show a range of fractionation. On the basis of their chemical and isotopic abundances, it is unlikely that the lavas are related by a single simple process of magmatic differentiation. We suggest that the mantle source region of these basalts was chemically and isotopically heterogeneous. The chemistry of LREE-depleted tholeiitic basalt dredged from near the axis of the extinct Galapagos Rise indicates complex petrogenesis and differentiation. The presence of tholeiitic basalts here indicates that unlike the Guadalupe and Mathematician fossil ridges, the Galapagos Rise has not been the site of voluminous post-abandonment alkalic volcanism. Alkalic basalts of picritic bulk composition dredged from an elongate seamount near the Galapagos Rise do not represent liquid compositions. Instead, we suggest that these alkalic liquids contain added olivine and plagioclase xenocrysts. Although most of the samples analyzed are very fresh, a few have been altered. The latter exhibit characteristic chemical and isotopic effects of seawater alteration.

  3. Sedimentology, geochemistry and rock magnetic properties of beach sands in Galapagos Islands - implications for nesting marine turtles

    NASA Astrophysics Data System (ADS)

    Perez-Cruz, L.; Urrutia-Fucugauchi, J.; Vazquez-Gutierrez, F.; Carranza-Edwards, A.

    2007-12-01

    Marine turtles are well known for their navigation ability in the open ocean and fidelity to nesting beaches. Green turtle adult females migrate from foraging areas to island nesting beaches, traveling hundreds or thousands of kilometers each way. The marine turtle breeding in the Galapagos Islands is the Green Sea Turtle (Chelonia mydas agassisi); fairly common throughout the islands but with nesting sites located at Las Bachas (Santa Cruz), Barahona and Quinta Playa (Isabela), Salinas (Baltra), Gardner Bay (Española) and Bartolomé Islet. In order to characterize and to identify the geochemical signature of nesting marine turtle beaches in Galapagos Islands, sedimentological, geochemical and rock magnetic parameters are used. A total of one hundred and twenty sand samples were collected in four beaches to relate compositional characteristics between equivalent areas, these are: Las Bachas, Salinas, Barahona and Quinta Playa. Grain size is evaluated using laser particle analysis (Model Coulter LS 230). Bulk ICP-MS geochemical analysis is performed, following trace elements are analyzed: Al, V, Cr, Co, Ni, Cu, Zn, Cd, Ba, Pb, Fe, Mn, K, Na, Mg, Sr, Ca and Hg; and low-field magnetic susceptibility is measured in all samples at low and high frequencies. Granulometric analysis showed that Barahona and Quinta Playa are characterized for fine grained sands. In contrast, Salinas and Las Bachas exhibit medium to coarse sands. Trace metals concentrations and magnetic susceptibility show different distribution patterns in the beach sands. Calcium is the most abundant element in the samples. In particular, Co, K, and Na show similar concentrations in the four beaches. Las Bachas beach shows highest concentrations of Pb and Hg (maximum values 101.1 and 118.5 mg/kg, respectively), we suggest that the enrichment corresponds to an anthropogenic signal. Salinas beach samples show high concentrations of Fe, V, Cr, Zn, Mn and the highest values of magnetic susceptibility (maximum

  4. Searching for Seismic Signatures of a Plume Source at the Base of the Mantle Below the Galapagos Island Hotspot

    NASA Astrophysics Data System (ADS)

    Vanacore, E.; Niu, F.

    2007-12-01

    This study analyzes SKS and SKKS waveforms recorded on the BOLIVAR array in Venezuela and the BANJO array in South America from earthquake sources located in Tonga and Alaska regions to characterize the lower mantle beneath the Galapagos Islands. The data analysis applies two independent methods, residual differential SKKS-SKS travel times and anisotropy measurements, to examine the historically unsampled region. The residual differential travel time observations were performed using 21 earthquakes from the Tonga trench with magnitudes greater than 5.5 Mw that were recorded on the Bolivar array. Only data that was deemed to have a high SNR for both the SKS and SKKS phases were retained for analysis. Significant positive values of differential travel time that indicate low velocity along the SKKS raypaths are detected east of ~\\m270° longitude. The anisotropy data set consists of 31 intermediate and deep focus earthquakes from the Tonga and Aleutian trenches recorded on the BOLIVAR and BANJO arrays respectively. The anisotropy fast axis angle and time lag of the two phases are calculated using the 1-layer cross-convolution method of Menke and Levin (2003) with a maximum time lag window of 3 seconds. We retain results with an amplitude normalized squared L2 norm value of 0.6 or less for analysis. Because the raypaths of the SKS and SKKS phases are similar in the upper mantle and sample different regions of the lower mantle, we attribute inconsistencies between the two anisotropy to difference of the mantle structure near the CMB. We define significant difference in the azimuth of the fast axis as any difference between the SKSac and SKKSac measurements greater than 15 degrees. The dataset is dominated by inconsistent fast axis azimuth measurements between the SKSac and SKKSac phases, but does not isolate a single geographic region. Comparison of the splitting time measurements yields that inconsistency between the two phases is more significant, greater than 0.5 s

  5. Imaging spatial and temporal seismic source variations at Sierra Negra Volcano, Galapagos Islands using back-projection methods

    NASA Astrophysics Data System (ADS)

    Kelly, C. L.; Lawrence, J. F.; Ebinger, C. J.

    2013-12-01

    Imaging spatial and temporal seismic source variations at Sierra Negra Volcano, Galapagos Islands using back-projection methods Cyndi Kelly1, Jesse F. Lawrence1, Cindy Ebinger2 1Stanford University, Department of Geophysics, 397 Panama Mall, Stanford, CA 94305, USA 2University of Rochester, Department of Earth and Environmental Science, 227 Hutchison Hall, Rochester, NY 14627, USA Low-magnitude seismic signals generated by processes that characterize volcanic and hydrothermal systems and their plumbing networks are difficult to observe remotely. Seismic records from these systems tend to be extremely 'noisy', making it difficult to resolve 3D subsurface structures using traditional seismic methods. Easily identifiable high-amplitude bursts within the noise that might be suitable for use with traditional seismic methods (i.e. eruptions) tend to occur relatively infrequently compared to the length of an entire eruptive cycle. Furthermore, while these impulsive events might help constrain the dynamics of a particular eruption, they shed little insight into the mechanisms that occur throughout an entire eruption sequence. It has been shown, however, that the much more abundant low-amplitude seismic 'noise' in these records (i.e. volcanic or geyser 'tremor') actually represents a series of overlapping low-magnitude displacements that can be directly linked to magma, fluid, and volatile movement at depth. This 'noisy' data therefore likely contains valuable information about the processes occurring in the volcanic or hydrothermal system before, during and after eruption events. In this study, we present a new method to comprehensively study how the seismic source distribution of all events - including micro-events - evolves during different phases of the eruption sequence of Sierra Negra Volcano in the Galapagos Islands. We apply a back-projection search algorithm to image sources of seismic 'noise' at Sierra Negra Volcano during a proposed intrusion event. By analyzing

  6. Time-averaged paleomagnetic field at the equator: Complete data and results from the Galapagos Islands, Ecuador

    USGS Publications Warehouse

    Gromme, Sherman; Mankinen, Edward A.; Prévot, Michel

    2010-01-01

    We present here the complete paleomagnetic laboratory results from a collection of approximately 1500 oriented cores from all 16 of the Galapagos Islands, Ecuador, collected by Allan Cox in 1964–1965 but nearly all previously unpublished. The islands are located in the eastern Pacific Ocean within 1.4° of latitude from the equator and range in age from historically erupted to 3 Ma, mostly determined by published K-Ar and 3He isotopic dating. The number of sites collected on each island ranges from 1 to 28, for a total of 186. After combining duplicate site mean directions, 149 are used for an overall mean direction and 8 represent excursions and one reversal path. Divided by geomagnetic polarity chron, 110 site means are Brunhes or Jaramillo (normal polarity), 27 are Matuyama (reversed polarity), and 12 are Gauss (both polarities). We have completed the magnetic cleaning that was commenced in the late 1960s. Secondary (mostly viscous) magnetizations were nearly all removed by alternating field demagnetization at 10 mT. We have used the so-called blanket cleaning method, generally at 10 mT. All sites were in basalt flows and gave good paleomagnetic results; none was rejected in toto, and only a few core specimens were magnetically unsatisfactory. Nearly all sites had eight independently oriented cores, and within-site angular standard deviations of directions range from 1° to 8°. We used both Fisher and Bingham statistics to analyze the data and found that many of the direction populations are strongly elongate along the paleomagnetic meridian, while the corresponding virtual pole (VGP) populations are essentially circularly distributed. The paleomagnetic poles, calculated as the means of VGPs, are as follows: Brunhes and Jaramillo, north latitude = 86.9°, east longitude = 245.1°, and 95% confidence radius A95 = 1.9°; Matuyama, latitude = 87.2°, longitude = 158.2°, and A95 = 3.8°; Gauss, latitude = 83.0°, longitude = 204.7°, and A95 = 7.0°. These

  7. Identifying the provenance of Leach's storm petrels in the North Atlantic using polychlorinated biphenyl signatures derived from comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry.

    PubMed

    Megson, David; Brown, Thomas A; Johnson, Glenn W; O'Sullivan, Gwen; Bicknell, Anthony W J; Votier, Stephen C; Lohan, Maeve C; Comber, Sean; Kalin, Robert; Worsfold, Paul J

    2014-11-01

    PCB signatures can be used for source identification, exposure studies, age dating and bio-monitoring. This study uses comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GCxGC-ToFMS) to produce a PCB signature comprised of over 80 PCBs for individual Leach's storm petrels (Oceanodroma leucorhoa). The Leach's storm petrel is a relatively small, elusive, understudied pelagic bird, which only returns to remote islands under darkness during the breeding season. Samples were obtained from 25 Leach's storm petrels found dead in Canada and the UK following storm events in 2006 and 2009. Tissue samples were extracted and analysed by GCxGC-ToFMS and results showed that 83 PCB congeners were present in >60% of samples. An assessment of the PCB signature in four different tissue types showed that it did not vary greatly in samples obtained from the gut, heart, liver and stomach. Multivariate statistical analysis identified a distinctive PCB signature in birds from Canada and Europe which was used to identify the regional provenance and transatlantic movement of individual birds. The findings showcase the ability of GCxGC-ToFMS to provide the high quality congener specific analysis that is necessary for PCB fingerprinting, as well as highlighting the potential of PCB signatures for use in ecological studies of movement, foraging and behaviour. PMID:25113202

  8. Identifying the provenance of Leach's storm petrels in the North Atlantic using polychlorinated biphenyl signatures derived from comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry.

    PubMed

    Megson, David; Brown, Thomas A; Johnson, Glenn W; O'Sullivan, Gwen; Bicknell, Anthony W J; Votier, Stephen C; Lohan, Maeve C; Comber, Sean; Kalin, Robert; Worsfold, Paul J

    2014-11-01

    PCB signatures can be used for source identification, exposure studies, age dating and bio-monitoring. This study uses comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GCxGC-ToFMS) to produce a PCB signature comprised of over 80 PCBs for individual Leach's storm petrels (Oceanodroma leucorhoa). The Leach's storm petrel is a relatively small, elusive, understudied pelagic bird, which only returns to remote islands under darkness during the breeding season. Samples were obtained from 25 Leach's storm petrels found dead in Canada and the UK following storm events in 2006 and 2009. Tissue samples were extracted and analysed by GCxGC-ToFMS and results showed that 83 PCB congeners were present in >60% of samples. An assessment of the PCB signature in four different tissue types showed that it did not vary greatly in samples obtained from the gut, heart, liver and stomach. Multivariate statistical analysis identified a distinctive PCB signature in birds from Canada and Europe which was used to identify the regional provenance and transatlantic movement of individual birds. The findings showcase the ability of GCxGC-ToFMS to provide the high quality congener specific analysis that is necessary for PCB fingerprinting, as well as highlighting the potential of PCB signatures for use in ecological studies of movement, foraging and behaviour.

  9. Allozymic variability of Riftia pachyptila populations from the Galapagos Rift and 21$deg;N hydrothermal vents

    NASA Astrophysics Data System (ADS)

    Bucklin, Ann

    1988-10-01

    Species endemic to hydrothermal vent environments face difficult ecological and evolutionary conditions, especially since vent sites are irregularly distributed in space and ephemeral. Theoretical predictions for an optimal life history for an endemic organism may not be matched by one of the vent community's prominent species, the vestimentiferan Riftia pachyptila. Population samples were collected by submersible from vent sites along the Galapagos Rift and at 21°N along the East Pacific Rise. Allozymes were used to examine the population genetics of R. pachyptila, including the estimation of genetic variability of the species and differentiation of populations at different vent sites. For the 13 enzyme loci assayed by starch-gel electrophoresis, 31% were polymorphic. Heterozygosity was low: 1.5%. Genetic divergence between samples from the two regions was small but significant: genetic distance, Nei's D, was 0.008 and Wright's measure of variance partitioning, FST = 0.025 ( p < 0.05) after correction for small sample sizes. Genotypic frequencies also provided evidence of the differentiation of populations: there was a deficiency of one class of heterozygotes ( Pgm-1 98/100) in the pooled samples. The slight genetic differentiation may result from low genetic variability, which may prevent the use of allozymes as markers of gene flow. Endemic vent species may experience bottlenecks during colonization of new vent sites and extinction as vents become inactive. Low variability is a predictable outcome of repeated bouts of colonization and extinction, during which the effects of random genetic drift may rapidly decrease genetic variability.

  10. Mama's boy: sex differences in juvenile survival in a highly dimorphic large mammal, the Galapagos sea lion.

    PubMed

    Kraus, C; Mueller, B; Meise, K; Piedrahita, P; Pörschmann, U; Trillmich, F

    2013-04-01

    In many mammals, early survival differs between the sexes, with males proving the more fragile sex ["Fragile male (FM) hypothesis"], especially in sexually dimorphic species where males are the larger sex. Male-biased allocation (MBA) by females may offset this difference. Here, we evaluate support for the FM and MBA hypotheses using a dataset on Galapagos sea lions (Zalophus wollebaeki). We statistically model sex-specific survival as it depends on body mass and environmental conditions (sea surface temperature, SST, a correlate of marine productivity) at three developmental stages, the perinatal phase (1st month), the main lactation period (1st year), and the weaning period (2nd year). Supporting the FM hypothesis, we found that, early in life (1st month), at equal birth mass, males survived less well than females. During the remainder of the first year of life, male survival was actually less sensitive to harsh environmental conditions than that of females, contradicting the FM hypothesis and supporting the MBA hypothesis. During the second year of life, only male survival suffered with high SSTs as predicted by the FM hypothesis. At each developmental stage, observed survival rates were almost equal for both sexes, suggesting that mothers buffer against the inherent fragility of male offspring through increased allocation, thereby masking the differences in survival prospects between the sexes.

  11. Every inch a finch: a commentary on Grant (1993) 'Hybridization of Darwin's finches on Isla Daphne Major, Galapagos'.

    PubMed

    Bell, Graham

    2015-04-19

    One of the most familiar features of the natural world is that most animals and plants fall into distinct categories known as species. The attempt to understand the nature of species and the origin of new species was the enterprise that drove the early development of evolutionary biology and has continued to be a major focus of research. Individuals belonging to the same species usually share a distinctive appearance and way of life, and they can mate together successfully and produce viable offspring. New species may evolve, therefore, either through ecological divergence or through sexual isolation. The balance between these processes will depend on the extent of hybridization, especially in the early stages of divergence. Detecting and measuring hybridization in natural populations, however, requires intensive, long-term field programmes that are seldom undertaken, leaving a gap in our understanding of species formation. The finch community of a small, isolated island in the Galapagos provided an opportunity to discover how frequently hybridization takes place between closely related species in a pristine location, and Peter Grant's paper, published in Philosophical Transactions B in 1993, reports the observations that he and his collaborators made during the first 20 years of what is now one of the classical studies of evolution in action. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society.

  12. Weaker axially dipolar time-averaged paleomagnetic field based on multidomain-corrected paleointensities from Galapagos lavas.

    PubMed

    Wang, Huapei; Kent, Dennis V; Rochette, Pierre

    2015-12-01

    The geomagnetic field is predominantly dipolar today, and high-fidelity paleomagnetic mean directions from all over the globe strongly support the geocentric axial dipole (GAD) hypothesis for the past few million years. However, the bulk of paleointensity data fails to coincide with the axial dipole prediction of a factor-of-2 equator-to-pole increase in mean field strength, leaving the core dynamo process an enigma. Here, we obtain a multidomain-corrected Pliocene-Pleistocene average paleointensity of 21.6 ± 11.0 µT recorded by 27 lava flows from the Galapagos Archipelago near the Equator. Our new result in conjunction with a published comprehensive study of single-domain-behaved paleointensities from Antarctica (33.4 ± 13.9 µT) that also correspond to GAD directions suggests that the overall average paleomagnetic field over the past few million years has indeed been dominantly dipolar in intensity yet only ∼ 60% of the present-day field strength, with a long-term average virtual axial dipole magnetic moment of the Earth of only 4.9 ± 2.4 × 10(22) A ⋅ m(2). PMID:26598664

  13. Weaker axially dipolar time-averaged paleomagnetic field based on multidomain-corrected paleointensities from Galapagos lavas

    PubMed Central

    Wang, Huapei; Kent, Dennis V.; Rochette, Pierre

    2015-01-01

    The geomagnetic field is predominantly dipolar today, and high-fidelity paleomagnetic mean directions from all over the globe strongly support the geocentric axial dipole (GAD) hypothesis for the past few million years. However, the bulk of paleointensity data fails to coincide with the axial dipole prediction of a factor-of-2 equator-to-pole increase in mean field strength, leaving the core dynamo process an enigma. Here, we obtain a multidomain-corrected Pliocene–Pleistocene average paleointensity of 21.6 ± 11.0 µT recorded by 27 lava flows from the Galapagos Archipelago near the Equator. Our new result in conjunction with a published comprehensive study of single-domain–behaved paleointensities from Antarctica (33.4 ± 13.9 µT) that also correspond to GAD directions suggests that the overall average paleomagnetic field over the past few million years has indeed been dominantly dipolar in intensity yet only ∼60% of the present-day field strength, with a long-term average virtual axial dipole magnetic moment of the Earth of only 4.9 ± 2.4 × 1022 A⋅m2. PMID:26598664

  14. Visual Observations and Geologic Settings of the Newly-Discovered Black Smoker Vent Sites Across the Galapagos Ridge-Hotspot Intersection

    NASA Astrophysics Data System (ADS)

    Anderson, P.; Haymon, R.; MacDonald, K.; White, S.

    2006-12-01

    Nearly one-fifth of the global mid-ocean ridge is hotspot-affected, yet very little is known about how hotspots affect quantity and distribution of high-temperature hydrothermal vents along the ridge. During the 2005-06 GalAPAGoS expedition, acoustic and plume sensor surveys were conducted across the Galapagos ridge- hotspot intersection, lon. 94.5ºW- lon. 89.5ºW, to map fine scale geologic features and locate hydrothermal plumes emanating from the ridge crest. Where significant plumes were detected, the Medea fiber-optic camera sled was used successfully to find and image high-temperature vents on the seafloor. With Medea we discovered and imaged the first active and recently extinct black smokers known along the entire Galapagos Spreading Center (GSC), and documented the geologic setting of these vents. The Medea survey imaged numerous inactive vents as well as 3 active high-temperature vent fields along the ridge at 94º 04.5'W (Navidad Site), 91º56.2'W (Iguanas Site) and 91º54.3'W (Pinguinos Site). Two recently extinct vent fields also were identified at 91º23.4'-23.7'W and 91º13.8'W. All of the high-temperature vent sites that we identified along the GSC are found above relatively shallow AMC reflectors and are located in the middle 20% of ridge segments. Without exception the vent sites are located along fissures atop constructional axial volcanic ridges (AVR's) composed of relatively young pillow basalts. In some cases, the vents were associated with collapses adjacent to the fissures. The fissures appear to be eruptive sources of the pillow lavas comprising the AVR's. Video images of the chimneys show mature, cylindrical structures, up to 14m high; little diffuse flow; few animals; and some worm casts and dead clam shells, suggesting prior habitation. We conclude that distribution of the vents is controlled by magmatic processes, (i.e., by locations of shallow AMC magma reservoirs and eruptive fissures above dike intrusions), and that there is

  15. Flow rates and reaction rates in the Galapagos Rise spreading center hydrothermal system as inferred from 228Ra/226Ra in vesicomyid clam shells

    PubMed Central

    Turekian, Karl K.; Cochran, J. Kirk

    1986-01-01

    The 228Ra/226Ra ratios in a previously dated vesicomyid clam shell were used to determine that seawater was in contact with mid-oceanic-ridge basalt glass for 22-45 years prior to arrival to the surface at 350°C at the Galapagos Rise Spreading Center. The minimum rate of reaction for the 45-year sojourn time, based on a water/rock ratio of 2.8 derived from 226Ra concentrations, is 8 g of basalt altered per kg of seawater per year. PMID:16593746

  16. Feather mercury concentrations in Southern Ocean seabirds: Variation by species, site and time.

    PubMed

    Becker, Peter H; Goutner, Vassilis; Ryan, Peter G; González-Solís, Jacob

    2016-09-01

    We studied mercury contamination in 25 seabird species breeding along a latitudinal gradient across the Southern Ocean, from Gough Island (40°S) through Marion Island (47°S) to Byers Peninsula (63°S). Total mercury concentrations in body feather samples of adults caught at breeding colonies from 2008 to 2011 were determined. Krill (Euphausia spp.) and other zooplankton consumers had low mercury concentrations (gentoo penguin Pygoscelis papua, chinstrap penguin Pseudomonas Antarctica, common diving petrel Pelecanoides urinatrix, broad-billed prion Pachyptila vittata; mean levels 308-753 ng g(-1)), whereas seabirds consuming squid or carrion had high mercury concentrations (ascending order: Kerguelen petrel Aphrodroma brevirostris, southern giant petrel Macronectes giganteus, soft-plumaged petrel Pterodroma mollis, sooty albatross Phoebetria fusca, Atlantic petrel Pterodroma incerta, northern giant petrel Macronectes halli, great-winged petrel Pterodroma macroptera; 10,720-28038 ng g(-1)). The two species with the highest mercury concentrations, northern giant petrels and great-winged petrels, bred at Marion Island. Among species investigated at multiple sites, southern giant petrels had higher mercury levels at Marion than at Gough Island and Byers Peninsula. Mercury levels among Byers Peninsula seabirds were low, in two species even lower than levels measured 10 years before at Bird Island, South Georgia. Replicate measurements after about 25 years at Gough Island showed much higher mercury levels in feathers of sooty albatrosses (by 187%), soft-plumaged petrels (53%) and Atlantic petrels (49%). Concentrations similar to the past were detected in southern giant petrels at Gough and Marion islands, and in northern giant petrels at Marion. There were no clear indications that timing of moult or migratory behavior affected mercury contamination patterns among species. Causes of inter-site or temporal differences in mercury contamination could not be verified

  17. Feather mercury concentrations in Southern Ocean seabirds: Variation by species, site and time.

    PubMed

    Becker, Peter H; Goutner, Vassilis; Ryan, Peter G; González-Solís, Jacob

    2016-09-01

    We studied mercury contamination in 25 seabird species breeding along a latitudinal gradient across the Southern Ocean, from Gough Island (40°S) through Marion Island (47°S) to Byers Peninsula (63°S). Total mercury concentrations in body feather samples of adults caught at breeding colonies from 2008 to 2011 were determined. Krill (Euphausia spp.) and other zooplankton consumers had low mercury concentrations (gentoo penguin Pygoscelis papua, chinstrap penguin Pseudomonas Antarctica, common diving petrel Pelecanoides urinatrix, broad-billed prion Pachyptila vittata; mean levels 308-753 ng g(-1)), whereas seabirds consuming squid or carrion had high mercury concentrations (ascending order: Kerguelen petrel Aphrodroma brevirostris, southern giant petrel Macronectes giganteus, soft-plumaged petrel Pterodroma mollis, sooty albatross Phoebetria fusca, Atlantic petrel Pterodroma incerta, northern giant petrel Macronectes halli, great-winged petrel Pterodroma macroptera; 10,720-28038 ng g(-1)). The two species with the highest mercury concentrations, northern giant petrels and great-winged petrels, bred at Marion Island. Among species investigated at multiple sites, southern giant petrels had higher mercury levels at Marion than at Gough Island and Byers Peninsula. Mercury levels among Byers Peninsula seabirds were low, in two species even lower than levels measured 10 years before at Bird Island, South Georgia. Replicate measurements after about 25 years at Gough Island showed much higher mercury levels in feathers of sooty albatrosses (by 187%), soft-plumaged petrels (53%) and Atlantic petrels (49%). Concentrations similar to the past were detected in southern giant petrels at Gough and Marion islands, and in northern giant petrels at Marion. There were no clear indications that timing of moult or migratory behavior affected mercury contamination patterns among species. Causes of inter-site or temporal differences in mercury contamination could not be verified

  18. Hydrothermal Plume Mapping Along the Hotspot-affected Galapagos Spreading Center Finds High-Temperature Vent Sites are Anomalously Scarce

    NASA Astrophysics Data System (ADS)

    Baker, E. T.; Resing, J. A.; Walker, S. L.; Lebon, G. T.; Nakamura, K.; Haymon, R. M.; White, S. M.; MacDonald, K. C.

    2006-12-01

    Systematic searches for hydrothermal activity along midocean ridges (MORs) demonstrate that the spatial density of hydrothermal activity is a robust linear function of spreading rate. This trend argues that the availability of mantle heat is the first order control on the distribution of seafloor vent fields. However, some crustal thermal models predict that the thicker, hotter, more ductile crust associated with hotspots substantially reduces convective hydrothermal cooling, explaining observations of axial magma chambers (AMC) at shallower depths than found on normal MORs. In Dec-Jan 2006 we tested this hypothesis by mapping hydrothermal plumes overlying the hotspot-affected Galapagos Spreading Center (GSC) from 95°-89.6°W, using a dual-pass, side-scan deep tow with an array of plume sensors spanning 50- 250 m above bottom. The western GSC near 91°-92.5°W has axial-high morphology, shallow and quasi-continuous AMC, and thick (8 km) crust, changing to a transitional morphology, deeper and more discontinuous AMC, and normal (6 km) crust from 93° to 95°W. The eastern GSC, 90.5°- 89.6°W is also an axial high and presumably has crustal characteristics similar to the western GSC at 91°-92.5°W. We identified hydrothermal plumes by anomalies in light backscattering (NTU) from a vertical array of MAPR sensors along the tow line, plus redox potential (Eh) measured continuously in-situ on the tow body at a nominal elevation of 100 m. Many plumes were subsequently confirmed by CTD tows and sampling. Only three areas of extensive and intense plumes were observed: 90.52°-90.63°W, 91.78°- 91.96°W, and 94°-94.1°W. Maximum plume rise at the latter two sites exceeded 200 m, indicative of high-temperature venting that was confirmed by camera tows. Some 25 other NTU and Eh anomalies were detected along ~1000 km of trackline, but none were >5 km in length. The primary result of our survey is that hydrothermal plumes were scarce for a ridge spreading at ~60 mm

  19. Applicability of Single-Camera Photogrammetry to Determine Body Dimensions of Pinnipeds: Galapagos Sea Lions as an Example

    PubMed Central

    Meise, Kristine; Mueller, Birte; Zein, Beate; Trillmich, Fritz

    2014-01-01

    Morphological features correlate with many life history traits and are therefore of high interest to behavioral and evolutionary biologists. Photogrammetry provides a useful tool to collect morphological data from species for which measurements are otherwise difficult to obtain. This method reduces disturbance and avoids capture stress. Using the Galapagos sea lion (Zalophus wollebaeki) as a model system, we tested the applicability of single-camera photogrammetry in combination with laser distance measurement to estimate morphological traits which may vary with an animal’s body position. We assessed whether linear morphological traits estimated by photogrammetry can be used to estimate body length and mass. We show that accurate estimates of body length (males: ±2.0%, females: ±2.6%) and reliable estimates of body mass are possible (males: ±6.8%, females: 14.5%). Furthermore, we developed correction factors that allow the use of animal photos that diverge somewhat from a flat-out position. The product of estimated body length and girth produced sufficiently reliable estimates of mass to categorize individuals into 10 kg-classes of body mass. Data of individuals repeatedly photographed within one season suggested relatively low measurement errors (body length: 2.9%, body mass: 8.1%). In order to develop accurate sex- and age-specific correction factors, a sufficient number of individuals from both sexes and from all desired age classes have to be captured for baseline measurements. Given proper validation, this method provides an excellent opportunity to collect morphological data for large numbers of individuals with minimal disturbance. PMID:24987983

  20. Whale shark (Rhincodon typus) seasonal presence, residence time and habitat use at darwin island, galapagos marine reserve.

    PubMed

    Acuña-Marrero, David; Jiménez, Jesús; Smith, Franz; Doherty, Paul F; Hearn, Alex; Green, Jonathan R; Paredes-Jarrín, Jules; Salinas-de-León, Pelayo

    2014-01-01

    The life history of the whale shark (Rhincodon typus), including its reproductive ecology, still remains largely unknown. Here, we present results from the first whale shark population study around Darwin Island, Galapagos Marine Reserve. Following a diversified approach we characterized seasonal occurrence, population structure and size, and described habitat use of whale sharks based on fine scale movements around the island. Whale shark presence at Darwin Island was negatively correlated with Sea Surface Temperature (SST), with highest abundance corresponding to a cool season between July and December over six years of monitoring. From 2011 to 2013 we photo-identified 82 whale sharks ranging from 4 to 13.1 m Total Length (TL). Size distribution was bimodal, with a great majority (91.5%) of adult female individuals averaging 11.35 m±0.12 m (TL±SE), all but one showing signs of a potential pregnancy. Population dynamics models for apparently pregnant sharks estimated the presence of 3.76±0.90 (mean ± SE) sharks in the study area per day with an individual residence time of 2.09±0.51 (mean ± SE) days. Movement patterns analysis of four apparently pregnant individuals tracked with acoustic tags at Darwin Island revealed an intense use of Darwin's Arch, where no feeding or specific behavior has been recorded, together with periodic excursions around the island's vicinity. Sharks showed a preference for intermediate depths (20-30 m) with occasional dives mostly to mid-water, remaining the majority of their time at water temperatures between 24-25°C. All of our results point to Darwin Island as an important stopover in a migration, possibly with reproductive purposes, rather than an aggregation site. Current studies carried out in this area to investigate regional scale movement patterns may provide essential information about possible pupping grounds for this enigmatic species. PMID:25551553

  1. Whale shark (Rhincodon typus) seasonal presence, residence time and habitat use at darwin island, galapagos marine reserve.

    PubMed

    Acuña-Marrero, David; Jiménez, Jesús; Smith, Franz; Doherty, Paul F; Hearn, Alex; Green, Jonathan R; Paredes-Jarrín, Jules; Salinas-de-León, Pelayo

    2014-01-01

    The life history of the whale shark (Rhincodon typus), including its reproductive ecology, still remains largely unknown. Here, we present results from the first whale shark population study around Darwin Island, Galapagos Marine Reserve. Following a diversified approach we characterized seasonal occurrence, population structure and size, and described habitat use of whale sharks based on fine scale movements around the island. Whale shark presence at Darwin Island was negatively correlated with Sea Surface Temperature (SST), with highest abundance corresponding to a cool season between July and December over six years of monitoring. From 2011 to 2013 we photo-identified 82 whale sharks ranging from 4 to 13.1 m Total Length (TL). Size distribution was bimodal, with a great majority (91.5%) of adult female individuals averaging 11.35 m±0.12 m (TL±SE), all but one showing signs of a potential pregnancy. Population dynamics models for apparently pregnant sharks estimated the presence of 3.76±0.90 (mean ± SE) sharks in the study area per day with an individual residence time of 2.09±0.51 (mean ± SE) days. Movement patterns analysis of four apparently pregnant individuals tracked with acoustic tags at Darwin Island revealed an intense use of Darwin's Arch, where no feeding or specific behavior has been recorded, together with periodic excursions around the island's vicinity. Sharks showed a preference for intermediate depths (20-30 m) with occasional dives mostly to mid-water, remaining the majority of their time at water temperatures between 24-25°C. All of our results point to Darwin Island as an important stopover in a migration, possibly with reproductive purposes, rather than an aggregation site. Current studies carried out in this area to investigate regional scale movement patterns may provide essential information about possible pupping grounds for this enigmatic species.

  2. Whale Shark (Rhincodon typus) Seasonal Presence, Residence Time and Habitat Use at Darwin Island, Galapagos Marine Reserve

    PubMed Central

    Acuña-Marrero, David; Jiménez, Jesús; Smith, Franz; Doherty, Paul F.; Hearn, Alex; Green, Jonathan R.; Paredes-Jarrín, Jules; Salinas-de-León, Pelayo

    2014-01-01

    The life history of the whale shark (Rhincodon typus), including its reproductive ecology, still remains largely unknown. Here, we present results from the first whale shark population study around Darwin Island, Galapagos Marine Reserve. Following a diversified approach we characterized seasonal occurrence, population structure and size, and described habitat use of whale sharks based on fine scale movements around the island. Whale shark presence at Darwin Island was negatively correlated with Sea Surface Temperature (SST), with highest abundance corresponding to a cool season between July and December over six years of monitoring. From 2011 to 2013 we photo-identified 82 whale sharks ranging from 4 to 13.1 m Total Length (TL). Size distribution was bimodal, with a great majority (91.5%) of adult female individuals averaging 11.35 m±0.12 m (TL±SE), all but one showing signs of a potential pregnancy. Population dynamics models for apparently pregnant sharks estimated the presence of 3.76±0.90 (mean ± SE) sharks in the study area per day with an individual residence time of 2.09±0.51 (mean ± SE) days. Movement patterns analysis of four apparently pregnant individuals tracked with acoustic tags at Darwin Island revealed an intense use of Darwin's Arch, where no feeding or specific behavior has been recorded, together with periodic excursions around the island's vicinity. Sharks showed a preference for intermediate depths (20–30 m) with occasional dives mostly to mid-water, remaining the majority of their time at water temperatures between 24–25°C. All of our results point to Darwin Island as an important stopover in a migration, possibly with reproductive purposes, rather than an aggregation site. Current studies carried out in this area to investigate regional scale movement patterns may provide essential information about possible pupping grounds for this enigmatic species. PMID:25551553

  3. Recruitment of marine invertebrates to hard substrates at deep-sea hydrothermal vents on the East Pacific Rise and Galapagos spreading center

    NASA Astrophysics Data System (ADS)

    Van Dover, Cindy Lee; Berg, Carl J.; Turner, Ruth D.

    1988-10-01

    Recruitment panels were placed at and near hydrothermal vent communities at three sites on the Galapagos spreading center and one site on the East Pacific Rise at 21°N. Deployment periods ranged from 26 days (Clam Acres, 21°N) to 260-320 days (Rose Garden, Garden of Eden, Mussel Bed, GSC) to 1216 days (Clam Acres). Recruitment of gastropod post-larvae and juveniles was observed on arrays deployed at Clam Acres for 26 days. Regardless of length of deployment, populations of polychaetes, mollusks, and barnacles colonizing the panels were predominantly post-larval, juvenile, or sub-adult stages. We suggest that some combination of competition, migration, and predation maintains these populations in immature stages. Size distributions of individuals within a taxon on panels deployed for 1216 days are broad, suggesting intermittent or continuous recruitment in many of the vent-associated species rather than a single episodic recruitment event. Folliculinid and foraminiferan protozoans were the most abundant eucaryotic organisms colonizing long-term deployments at Clam Acres. On the Galapagos spreading center, level of recruitment differed among the vent sites, with Rose Garden > Garden of Eden ≫ Mussel Bed. Recruitment of vent-associated species was greater on panels placed within vent communities compared to panels placed adjacent to these communities. This observation is consistent with the maintenance of vent communities in discrete regions of hydrothermal flux.

  4. Discovery and Distribution of Black Smokers on the Western Galapagos Spreading Center: Implications for Spatial and Temporal Controls on High Temperature Venting at Ridge/Hotspot Intersections

    NASA Astrophysics Data System (ADS)

    Haymon, R. M.; Anderson, P. G.; Baker, E. T.; Resing, J. A.; White, S. M.; MacDonald, K. C.

    2006-12-01

    Though nearly one-fifth of the mid-ocean ridge (MOR) lies on or near hotspots, it has been debated whether hotspots increase or decrease MOR hydrothermal flux, or affect vent biota. Despite hotspot enhancement of melt supply, high-temperature vent plumes are enigmatically sparse along two previously-surveyed ridge- hotspot intersections [Reykjanes Ridge (RR), Southeast Indian Ridge (SEIR)]. This has been attributed to crustal thickening by excess volcanism. During the 2005-06 GalAPAGoS expedition, we conducted nested sonar, plume, and camera surveys along a 540 km-long portion of the Galapagos Spreading Center (GSC) where the ridge intersects the Galapagos hotspot at lon. 94.5 -89.5 deg. W. Although MOR hydrothermal springs were first found along the eastern GSC crest in 1977 near lon. 86 deg. W, the GalAPAGoS smokers are the first active high-temperature vents to be found anywhere along the Cocos-Nazca plate boundary. Active and/or recently-inactive smokers were located beneath plumes at 5 sites on the seafloor between lon. 91 deg. W and 94.5 deg. W (see Anderson et al., this session) during near-bottom, real-time fiber-optic Medea camera surveys. Smokers occur along eruptive seafloor fissures atop axial volcanic ridges near the middles of ridge segments, mainly in areas underlain by relatively shallow, continuous axial magma chamber (AMC) seismic reflectors. These findings (1) support magmatic, rather than tectonic, control of GSC smoker distribution; (2) demonstrate that thick crust at MOR-hotspot intersections does not prevent high-temperature hydrothermal vents from forming; and, (3) appear to be inconsistent with models suggesting that enhanced hydrothermal cooling causes abrupt deepening of the AMC and transition from non-rifted to rifted GSC morphology near lon. 92.7 deg. W. The widely-spaced smoker sites located on different GSC segments exhibit remarkably similar characteristics and seafloor settings. Most sites are mature or extinct, and are on lava

  5. Understanding the mechanisms of antitropical divergence in the seabird White-faced Storm-petrel (Procellariiformes: Pelagodroma marina) using a multilocus approach.

    PubMed

    Silva, Mónica C; Matias, Rafael; Wanless, Ross M; Ryan, Peter G; Stephenson, Brent M; Bolton, Mark; Ferrand, Nuno; Coelho, M Manuela

    2015-06-01

    Analytical methods that apply coalescent theory to multilocus data have improved inferences of demographic parameters that are critical to understanding population divergence and speciation. In particular, at the early stages of speciation, it is important to implement models that accommodate conflicting gene trees, and benefit from the presence of shared polymorphisms. Here, we employ eleven nuclear loci and the mitochondrial control region to investigate the phylogeography and historical demography of the pelagic seabird White-faced Storm-petrel (Pelagodroma marina) by sampling subspecies across its antitropical distribution. Groups are all highly differentiated: global mitochondrial ΦST = 0.89 (P < 0.01) and global nuclear ΦST varies between 0.22 and 0.83 (all P < 0.01). The complete lineage sorting of the mitochondrial locus between hemispheres is corroborated by approximately half of the nuclear genealogies, suggesting a long-term antitropical divergence in isolation. Coalescent-based estimates of demographic parameters suggest that hemispheric divergence of P. marina occurred approximately 840 000 ya (95% HPD 582 000-1 170 000), in the absence of gene flow, and divergence within the Southern Hemisphere occurred 190 000 ya (95% HPD 96 000-600 000), both probably associated with the profound palaeo-oceanographic changes of the Pleistocene. A fledgling sampled in St Helena (tropical South Atlantic) suggests recent colonization from the Northern Hemisphere. Despite the great potential for long-distance dispersal, P. marina antitropical groups have been evolving as independent, allopatric lineages, and divergence is probably maintained by philopatry coupled with asynchronous reproductive phenology and local adaptation. PMID:25903359

  6. Modulation of the prolactin and the corticosterone stress responses: do they tell the same story in a long-lived bird, the Cape petrel?

    PubMed

    Angelier, Frédéric; Wingfield, John C; Trouvé, Colette; de Grissac, Sophie; Chastel, Olivier

    2013-02-01

    Over the last decades, the corticosterone stress response has been suggested as a major physiological tool to understand what strategy an individual might adopt in response to environmental perturbations. More recently, another hormone related to parental care--prolactin--has been suggested as a complementary tool to investigate this question. Indeed, both of these hormones are affected by stressors and are involved in parental decisions, such as deserting the nest. Because of these similarities, it remains unclear what the functional distinction between the prolactin and corticosterone stress responses is. Here, we investigated whether natural variations of the corticosterone and prolactin stress responses are functionally linked in free-living Cape petrel (Daption capense) parents. If prolactin and corticosterone mediate the same functional response to a stressor and are the proxies of the same response, we predict that corticosterone and prolactin stress responses (1) will be modulated according to the same factors; (2) will affect reproductive performances in the same way; and, (3) of course, will be correlated. Contrary to these predictions, we found that the corticosterone and prolactin stress responses were respectively modulated according to body condition and breeding status. Moreover, prolactin levels, but not corticosterone levels, were related to hatching success in this species. Finally, we did not find any significant correlation between these two stress responses under any circumstances (failed breeders, incubating or chick rearing birds) and this result was overall supported by a review of the existing literature. Therefore, these two stress responses do not seem to be tightly linked and we believe that they may provide complementary pieces of information on parental investment in birds. PMID:23142160

  7. Modulation of the prolactin and the corticosterone stress responses: do they tell the same story in a long-lived bird, the Cape petrel?

    PubMed

    Angelier, Frédéric; Wingfield, John C; Trouvé, Colette; de Grissac, Sophie; Chastel, Olivier

    2013-02-01

    Over the last decades, the corticosterone stress response has been suggested as a major physiological tool to understand what strategy an individual might adopt in response to environmental perturbations. More recently, another hormone related to parental care--prolactin--has been suggested as a complementary tool to investigate this question. Indeed, both of these hormones are affected by stressors and are involved in parental decisions, such as deserting the nest. Because of these similarities, it remains unclear what the functional distinction between the prolactin and corticosterone stress responses is. Here, we investigated whether natural variations of the corticosterone and prolactin stress responses are functionally linked in free-living Cape petrel (Daption capense) parents. If prolactin and corticosterone mediate the same functional response to a stressor and are the proxies of the same response, we predict that corticosterone and prolactin stress responses (1) will be modulated according to the same factors; (2) will affect reproductive performances in the same way; and, (3) of course, will be correlated. Contrary to these predictions, we found that the corticosterone and prolactin stress responses were respectively modulated according to body condition and breeding status. Moreover, prolactin levels, but not corticosterone levels, were related to hatching success in this species. Finally, we did not find any significant correlation between these two stress responses under any circumstances (failed breeders, incubating or chick rearing birds) and this result was overall supported by a review of the existing literature. Therefore, these two stress responses do not seem to be tightly linked and we believe that they may provide complementary pieces of information on parental investment in birds.

  8. Microhabitat variation in the hydrothermal vent mussel, Bathymodiolus thermophilus, at the Rose Garden vent on the Galapagos Rift

    NASA Astrophysics Data System (ADS)

    Fisher, C. R.; Childress, J. J.; Arp, A. J.; Brooks, J. M.; Distel, D.; Favuzzi, J. A.; Felbeck, H.; Hessler, R.; Johnson, K. S.; Kennicutt, M. C.; Macko, S. A.; Newton, A.; Powell, M. A.; Somero, G. N.; Soto, T.

    1988-10-01

    Clumps of Bathymodiolus thermophilus were collected from three discrete areas at the 'Rose Garden' site on the Galapagos Rift using the deep submersible Alvin. Two mussel collections were made from the central Riftia mass, an area associated with very active venting, and three other collections were of two different peripheral mussel clumps. Before collection the clumps were extensively photographed and the water at two of the 'microhabitats' was analysed in situ for oxygen silica, sulfide and temperature. Sulfide levels of up to 300 μM were recorded at the central collection site, while the highest sulfide level recorded at the peripheral site assayed was 35 μM. Levels of RuBP carboxylase activity in the gills were significantly higher in mussels collected from the central ' Riftia site' than in either peripheral site. ATP sulfurylase was significantly higher in the gills of mussels from the central clump than in one of the peripheral clump collections. The chemical composition (% water, protein, carbohydrate, lipid and ash) and stable carbon isotope ratios ( δ13C) of the mussels showed the same trends, with highest lipid and carbohydrate and the lowest water content and δ13C in the central site mussels. Similarly, the mussels from the central site were significantly depleted in stable nitrogen ( δ15N) when compared with the peripheral site mussels. Variations between sites and tissues of the same animal may be indicative of differential utilization of inorganic or dissolved molecular nitrogen sources. The condition index (CI = soft tissue dry mass / internal shell volume) was similar for all animals collected at Rose Garden. The presence of a commensal polychaete, Branchipolynoe symmytilida, in the mantle cavity of the mussels was also correlated with the collection site, with the highest incidence of occurrence in the central clump. Levels of the enzyme RuBP carboxylase are quite variable in B. thermophilus and are on the average much lower (0

  9. Heat transfer through the sediments of the mounds hydrothermal area, Galapagos Spreading Center at 86 /sup 0/W

    SciTech Connect

    Becker, K.; Von Herzen, R.P.

    1983-02-10

    Heat transfer processes at the mounds area of the Galapagos Spreading Center at 86 /sup 0/W are revealed by temperatures measured at roughly-equal10-m intervals in the 30 +- 10 m sediment at each of 12 holes at DSDP Leg 70 Sites 506--509 and by temperatures of up to five thermistors on eleven 8--12 m long piston cores. The 325 needle-probe values show a significant linear increase of thermal conductivity with depth in each core. About half of the temperature-thermal resistance profiles are nonlinear and are fit to a steady state, vertical pore water advection model. Results indicate high and variable total heat flow and localized hydrothermal discharge at roughly-equal10/sup -8/ m/s, associated with individual mounds. Recharge is indicated at similar rates in the low heat flow belt roughly-equal5 km south of the mounds and is suggested at slower rates in the intermediate heat flow (0.17--0.42 W/m/sup 2/) belt surrounding the mounds heat flow high. Possible slow entrained recharge within roughly-equal100 m of discharging mounds is suggested. Also suggested is strong local discharge along the major fault bounding the mounds crustal block to the north. About 95 km north of the spreading axis, at DSDP Site 510, temperatures in the 114-m sediment cover on 2.7-m.y. crust are linear, consistent with the suggestion that the hydraulic resistance of this layer is sufficient to seal off free hydrothermal exchange between basement and bottom water. The combination of heat flow data and the physical properties data of Karato and Becker (this issue) suggests that roughly-equal50 m of sediment may be a threshold thickness for sealing of hydrothermal circulation within basement, where the topography is smooth. We suggest that the formation of mounds may be associated with the forced localization of hydrothermal discharge through the sediment, as its thickness approaches this threshold value.

  10. Characterizing human-environment interactions in the Galapagos Islands: A case study of land use/land cover dynamics in Isabela Island

    NASA Astrophysics Data System (ADS)

    McCleary, Amy L.

    This dissertation examines contemporary land use and land cover (LULC) change in the communities and protected areas of Isabela Island to provide insights into human-environment interactions in the Galapagos Islands of Ecuador. The growing human presence in Galapagos over the last four decades has been accompanied by significant changes in LULC on inhabited islands in the archipelago. Local stakeholders and decision-makers have recently called for a more integrative approach to understanding interactions between people and the environment in the archipelago. This study is guided by two complementary bodies of work situated within the human-environment tradition of Geography---land change science and landscape ecology. First, support Vector Machine (SVM) and Object Based Image Analysis (OBIA) classifiers are evaluated for mapping LULC from high spatial resolution satellite images. The results show that thematic LULC classifications produced by OBIA are more accurate overall than those generated by SVM. However, important tradeoffs exist between improvements in classification accuracy and processing requirements. The composition and spatial configuration of LULC change are then mapped and quantified from a time series of QuickBird and WorldView-2 satellite images from 2003 to 2010. The pattern metric and change detection analyses reveal that land use change is extensive within the communities due to the expansion and consolidation of built-up areas, and fragmentation of and declines in agriculture. The Galapagos National Park is primarily transformed by exotic plant invasion, forests expansion, and shrinking coastal lagoons. Patterns of agricultural land abandonment, plant invasion, and forest expansion over the same period are described from pattern metric and overlay analyses. Potential drivers of these LULC transitions are identified from logistic regression models, descriptive statistics of agricultural surveys and population censuses, and interviews with

  11. Minor and trace element geochemistry of volcanic rocks dredged from the Galapagos spreading center: role of crystal fractionation and mantle heterogeneity.

    USGS Publications Warehouse

    Clague, D.A.; Frey, F.A.; Thompson, G.; Rindge, S.

    1981-01-01

    A wide range of rock types (abyssal tholeiite, Fe-Ti-rich basalt, andesite, and rhyodacite) were dredged from near 95oW and 85oW on the Galapagos spreading center. Computer modeling of major element compositions has shown that these rocks could be derived from common parental magmas by successive degrees of fractional crystallization. However, the P2O5/K2O ratio implies distinct mantle source compositions for the two areas. These source regions also have different rare earth element (REE) abundance patterns. The sequence of fractionated lavas differs for the two areas and indicates earlier fractionation of apatite and titanomagnetite in the lavas from 95oW. The mantle source regions for these two areas are interpreted to be depleted in incompatible (and volatile?) elements, although the source region beneath 95oW is less severely depleted in La and K. -Authors

  12. Mechanisms of population differentiation in seabirds.

    PubMed

    Friesen, V L; Burg, T M; McCoy, K D

    2007-05-01

    Despite recent advances in population genetic theory and empirical research, the extent of genetic differentiation among natural populations of animals remains difficult to predict. We reviewed studies of geographic variation in mitochondrial DNA in seabirds to test the importance of various factors in generating population genetic and phylogeographic structure. The extent of population genetic and phylogeographic structure varies extensively among species. Species fragmented by land or ice invariably exhibit population genetic structure and most also have phylogeographic structure. However, many populations (26 of 37) display genetic structure in the absence of land, suggesting that other barriers to gene flow exist. In these populations, the extent of genetic structure is best explained by nonbreeding distribution: almost all species with two or more population-specific nonbreeding areas (or seasons) have phylogeographic structure, and all species that are resident at or near breeding colonies year-round have population genetic structure. Geographic distance between colonies and foraging range appeared to have a weak influence on the extent of population genetic structure, but little evidence was found for an effect of colony dispersion or population bottlenecks. In two species (Galapagos petrel, Pterodroma phaeopygia, and Xantus's murrelet, Synthliboramphus hypoleucus), population genetic structure, and even phylogeographic structure, exist in the absence of any recognizable physical or nonphysical barrier, suggesting that other selective or behavioural processes such as philopatry may limit gene flow. Retained ancestral variation may be masking barriers to dispersal in some species, especially at high latitudes. Allopatric speciation undoubtedly occurs in this group, but reproductive isolation also appears to have evolved through founder-induced speciation, and there is strong evidence that parapatric and sympatric speciation occur. While many questions remain

  13. Development of algorithms to link the static model of Petrel with the dynamic model of OpenGeoSys and application to CO2 storage in a saline aquifer

    NASA Astrophysics Data System (ADS)

    Park, C.; Shinn, Y.

    2013-12-01

    A set of three algorithms named PET2OGS is developed to integrate the static model (Petrel) with the dynamic model (OpenGeoSys). PET2OGS consists of three sub-algorithms that convert finite difference methods (FDMs) grids to finite element methods (FEMs) grids. The algorithms and the workflow of the integration procedures are described in detail. After the proposed algorithms are tested on a variety of grids both in homogeneous and heterogeneous media, the integrated platform of the static and dynamic models is applied to model CO2 storage in a saline aquifer. A successful demonstration of the proposed algorithms proved a robust integration of the platform. With some minor modifications of the algorithms in the part of input and output, the proposed algorithms can be extended to integrate different combinations of FDM-based static models and FEM-based dynamic models beyond the example combination.

  14. Biomineralization and biosignatures of coralloid-type speleothems from lava tubes of Galapagos Islands: evidences on the fossil record of prokaryotes

    NASA Astrophysics Data System (ADS)

    Miller, Ana Z.; Garcia-Sanchez, Angela M.; Pereira, Manuel F. C.; Gazquez, Fernando; Calaforra, José M.; Forti, Paolo; Toulkeridis, Theofilos; Martínez-Frías, Jesús; Saiz-Jimenez, Cesareo

    2016-04-01

    Lava tubes have traditionally been considered of little interest from a mineralogical point of view. Recently, this type of volcanic caves has received particular attention because lava tubes have been described on Mars. Speleothems, or secondary mineral deposits in lava tubes are mainly composed of siliceous minerals. Coralloid-type speleothems are found either on basaltic cave walls or on the surface of other speleothems. Several authors attribute a microbially mediated origin to their formation. This type of speleothems was recorded within Royal Palm Cave of Santa Cruz Island in Galapagos Archipelago (Ecuador), a lava tube 600 m long, 5 to 15 m height and 2 to 10 m width. The Galapagos Islands are an archipelago of 19 volcanic islands located some 1500 km west of Ecuador, in the Pacific Ocean. These islands host one of the most biodiverse settings on Earth, studied by Charles Darwin. Beige and greyish small coralloids were collected in Royal Palm Cave and analysed by field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (FESEM-EDS), X-ray micro-computed tomography (micro-CT) and mineralogical analyses for morphological, 3D microstructural and compositional characterization, as well as for assessing microbe-mineral interactions and biogenicity. In addition, 16S rRNA gene analyses were performed to identify microbial communities associated with the coralloid-type speleothems. The coralloids showed internal compositional zonation along the growth direction of the speleothems, according to micro-CT data. Internal layering was clearly discernable by the differences in opacity of the distinct mineralogical phases to X-rays, being dominated by alteration products of siliceous composition, whereas more opaque phases, usually Ca-rich minerals, were dominant in the outermost part of the speleothems. X-ray diffraction and infrared spectroscopy reinforced that the first stage of deposition is mainly composed of opal A and clay minerals

  15. The effect of an East Pacific Rise offset on the formation of secondary cracks ahead of the Cocos-Nazca Rift at the Galapagos Triple Junction

    NASA Astrophysics Data System (ADS)

    Smith, D. K.; Montesi, L. G.; Schouten, H.; Zhu, W.

    2011-12-01

    A succession of short-lived, E-W trending cracks at the Galapagos Triple Junction north and south of the Cocos-Nazca (C-N) Rift, has been explained by a simple crack interaction model. The locations of where the cracks initiate are controlled by tensile stresses generated at the East Pacific Rise (EPR) by two interacting cracks: One representing the north-south trending EPR, and the other the large, westward propagating C-N Rift, whose tip is separated from the EPR by a distance D. The model predicts symmetric cracking at the EPR north and south of the C-N Rift tip. Symmetry in the distribution of cracks north and south of the C-N Rift is observed and especially remarkable between 2.5 and 1.5 Ma when the rapid jumping of cracks toward the C-N Rift appears synchronous. The rapid jumping can be explained by decreasing D, which means that the tip of the C-N Rift was moving closer to the EPR. Symmetry of cracking breaks down at 1.5 Ma, however, with the establishment of the Dietz Deep Rift, the southern boundary of the Galapagos microplate. Symmetry of cracking also breaks down on older crust to the east between about 100 35'W and 100 45'W (about 2.6 Ma) where a rapid jumping of cracks toward the C-N Rift is observed in the south cracking region. There is no evidence of similar rapid jumping in the north cracking region. It could be simply that the response to changing the value of D is not always as predicted. It could also be that the shape of the EPR has not always been symmetric about the C-N Rift, as assumed in the model. Currently, an overlapping spreading center with a 15 km east-west offset between the limbs of the EPR has formed at 1 50'N. We assess the importance of the geometry of the EPR on the crack interaction model. The model has been modified to include a ridge offset similar to what is observed today. We find that the region of stress enhancement at the EPR (where cracks initiate) is subdued south of the C-N Rift tip because of the EPR offset. It is

  16. New records of feather lice from some seabirds in Chile.

    PubMed

    Sepúlveda, M S; Palma, R L; Ochoa-Acuña, H

    1997-04-01

    Six species of chewing lice (Phthiraptera: Menoponidae, Philopteridae) are reported from four species of seabirds collected off the coast of Chile. They are Eidmanniella pellucida, Piagetiella transitans, and Piagetiella caputincisa, from a Guanay cormorant (Phalacrocorax bougainvillii); Harrisoniella ferox collected from a black-browed albatross (Diomedea melanophrys); Ancistrona vagelli from a white-necked petrel (Pterodroma externa); and Pelmatocerandra flinti collected from a Magellan diving petrel (Pelecanoides magellani). Eidmanniella pellucida and P. transitans are reported from Chile for the first time. Piagetiella caputincisa from the Guanay cormorant may be a contaminant from a red-legged shag (Phalacrocorax gaimardi). PMID:9131581

  17. Light attraction in endangered procellariiform birds: Reduction by shielding upward radiation

    USGS Publications Warehouse

    Reed, J.R.; Sincock, J.L.; Hailman, J.P.

    1985-01-01

    Autumnal attraction to man-made lighting causes heavy mortality in fledgling Hawaiian seabirds: Newell's shearwater (Puffinus auricularis newelli), dark-rumped petrel (Pterodroma phaeopygia sandwichensis), and band-rumpted storm-petrel (Oceanodroma castro). These threatened, endangered and rare species (respectively) approach and circle lights on their first flight from mountain nesting colonies on the island of Kauai to the sea. Lights of the largest resort were shielded to prevent upward radiation on alternate nights during 2 fledgling seasons. Shielding decreased attraction by nearly 40%. Most attraction occurred 1-4 h after sunset. Full moon dramatically decreased attraction, a phenomenon that has both theoretical and management implications.

  18. Diel use of a saltwater creek by white-tip reef sharks Triaenodon obesus (Carcharhiniformes: Carcharhinidae) in Academy Bay, Galapagos Islands.

    PubMed

    Peñiaherrera, César; Hearn, Alex R; Kuhn, Angela

    2012-06-01

    White-tip reef sharks are common inhabitants of the shallow waters surrounding the Galapagos Islands, where several known aggregation sites have become touristic attractions. With the aim to describe site fidelity and residency patterns of the white-tip reef sharks in a saltwater creek, we used the ultrasonic telemetry method. The study was undertaken in a saltwater channel South of Academy Bay, Santa Cruz Island, from May 2008-September 2009. A total of nine transmitters were attached to sharks and ultrasonic receivers were deployed at the inner and outside areas of the creek. From the total of fitted sharks, four lost their transmitters. The results obtained with the remaining sharks showed an elevated use of the inner area of the channel during the day, with more use of the external area during the night. However, none of the sharks were detected at the site every day, suggesting that they may have a number of preferred sites within their home range. More studies are needed to detail the home range and habitat use of this species, and to guide its protection level in the Academy Bay area.

  19. Diel use of a saltwater creek by white-tip reef sharks Triaenodon obesus (Carcharhiniformes: Carcharhinidae) in Academy Bay, Galapagos Islands.

    PubMed

    Peñiaherrera, César; Hearn, Alex R; Kuhn, Angela

    2012-06-01

    White-tip reef sharks are common inhabitants of the shallow waters surrounding the Galapagos Islands, where several known aggregation sites have become touristic attractions. With the aim to describe site fidelity and residency patterns of the white-tip reef sharks in a saltwater creek, we used the ultrasonic telemetry method. The study was undertaken in a saltwater channel South of Academy Bay, Santa Cruz Island, from May 2008-September 2009. A total of nine transmitters were attached to sharks and ultrasonic receivers were deployed at the inner and outside areas of the creek. From the total of fitted sharks, four lost their transmitters. The results obtained with the remaining sharks showed an elevated use of the inner area of the channel during the day, with more use of the external area during the night. However, none of the sharks were detected at the site every day, suggesting that they may have a number of preferred sites within their home range. More studies are needed to detail the home range and habitat use of this species, and to guide its protection level in the Academy Bay area. PMID:23894942

  20. A Small Ocean Rift Leads to a New View of the Galapagos Microplate: the Incipient Rift at 2 Degrees North, East of the East Pacific Rise

    NASA Astrophysics Data System (ADS)

    Klein, E. M.; Smith, D. K.; Williams, C. M.; Schouten, H.

    2004-12-01

    The Galapagos microplate (GMP) shares a complex plate boundary configuration with the surrounding Cocos, Nazca and Pacific plates. While the configuration of the microplate's southern boundary with the Nazca plate is relatively well understood, the nature of its northern boundary with the Cocos plate has remained more elusive. Work by Lonsdale and co-workers (1988; 1992) identified an "incipient" spreading center east of and orthogonal to the East Pacific Rise (EPR) at 2deg40minN, forming a portion of the northern boundary of the GMP. They described this spreading center as a slowly diverging, westward propagating rift, verging toward the EPR. In 2002, we mapped and sampled a broad region centered on the IR, extending ~140 km east of the EPR. Various geological, geophysical and rock sampling tools were used, including Seabeam2000 bathymetry and side-scan (amplitude); towed magnetometer; bottom photography (14 camera tows using the WHOI camera system); water column hydrothermal surveying and rock sampling. Our recent analysis of the bathymetric, side-scan and magnetic data suggests that the IR forms a lozenge-shaped feature, which tapers both westward toward the EPR and eastward, away from the EPR. Within the eastern half of the lozenge, there is a sinuous trough that trends ~100° to the southeast, along which reflection amplitudes indicate high-reflectivity consistent with relatively sparse sediment cover. The eastern end of this trough clearly cuts north-south-oriented abyssal hills and then dies out in the vicinity of 101deg29minW. The photographic results show sparsely sedimented lavas, often with delicate ornamentation and basaltic glass, with local in-filling of sediment between pillows. In a number of photographs, particularly along the eastern portion of the IR, lavas appear to emanate from local fissures with southeast-northwest orientations. Taken together, these data suggest that the IR is magmatically active along its length and has propagated eastward

  1. Experimental constraints on the generation of FeTi basalts, andesites, and rhyodacites at the Galapagos Spreading Center, 85°W and 95°W

    NASA Astrophysics Data System (ADS)

    Juster, Thomas C.; Grove, Timothy L.; Perfit, Michael R.

    1989-07-01

    One-atmosphere experiments conducted on a synthetic glass similar to Galapagos Spreading Center (GSC) FeTi basalt (POO.82N2), (Byerly et al., 1976) define liquid lines of descent at fO2 values between the quartz-fayalite-magnetite (QFM) buffer and 2 log units more oxidizing than the nickle-nickle oxide (NNO) buffer. The experiments provide a framework for understanding the development of FeTi basalts by fractionation at near-ocean floor conditions. GSC lavas from near 85°W initially follow a compositional trend, distinguished by FeO° (= FeO + 0.9Fe2O3) enrichment and SiO2 depletion, which is nearly identical to the trend observed in experiments at QFM to which olivine seeds were added. This compositional trend can be produced by crystallization along an olivine → pigeonite reaction boundary in a shallow crystal-rich magma reservoir. In contrast, GSC lavas from 95°W do not mimic the 1-atm liquid line of descent, but appear to have fractionated at somewhat higher pressure. Basaltic liquids from 95°W underwent fractional crystallization at 1-2 kbar, did not experience FeO° enrichment along an olivine → low-Ca pyroxene reaction boundary, and developed FeO° enrichment concomitant with SiO2 enrichment. This compositional variation is consistent with a differentiation process in which crystals are continually removed from contact with liquid. Rhyodacites from 95°W cannot be related to the basalts and FeTi basalts recovered at 95°W by shallow-level crystal fractionation. Instead, rhyolite liquids were formed either by fractionation of similar parents at greater depth and higher PH2O, or formed by fractionation of different parents. Andesite formed by mixing between basaltic and rhyodacitic liquids. As a consequence, mixed andesites define a trend of decreasing P2O5 which has been previously interpreted to represent apatite saturation at approximately 0.22 wt% P2O5, significantly earlier than at 85°W (where P2O5 decreases at approximately 0.7 wt% P2O5). Our

  2. DSL-120A High-Resolution, Near-Bottom Side Scan Sonar Imaging of Mid-Ocean Ridge Crests: East Pacific Rise, Galapagos Rift and Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Fornari, D.

    2003-04-01

    The DSL-120A 120kHz side-looking sonar system is one of the survey vehicles in the US National Deep Submergence Facility (NDSF) operated by the Woods Hole Oceanographic Institution for the academic community. Survey speeds for the DSL-120A sonar range from 1.0-1.5 knots depending on terrain roughness. The sonar fish is towed approx. 100 m above the seafloor yielding a backscatter imagery swath of 1.2 km and phase-bathymetry swath of approximately 500-600 m. Data resolution is 1 m for side scan imagery and 4 m for phase-bathymetry. DSL-120A data can resolve bathymetric features with linear dimensions more than 25x smaller than those detectable by hull-mounted multibeam sonars at ridge crest seafloor depths. Data resulting from the DSL-120A sonar system have provided the requisite base maps to understand the volcanic and tectonic evolution of seafloor in many geographic and tectonic settings including several segments of the mid-ocean ridge. These maps have provided site-specific information for planning and carrying out detailed photographic imaging, sampling, and other in situ investigations, and ocean crustal drilling. Backscatter images reveal variations in volcanic emplacement style at different spreading rate and tectonic settings along the MOR crest. DSL-120 sonar data have been collected at the Mid-Atlantic Ridge - 37N, the East Pacific Rise (between 9-10N, an overlapping spreading center at 3 20'N, and at 1 45'N) and within the tectonically dominated Galapagos Rift at 97.5W. Despite the 'fast' spreading nature of crust at the EPR between 1-10N, the sonar images show that volcanic emplacement changes dramatically along-strike depending on the local tectonic setting, and on more regional variations that are likely related to magmatic supply along and across adjacent ridge segments boundaries of various scales. Representative side scan images from these areas will be presented to illustrate different modes of volcanic eruption and emplacement styles

  3. Millennial-scale isotope records from a wide-ranging predator show evidence of recent human impact to oceanic food webs

    PubMed Central

    Wiley, Anne E.; Ostrom, Peggy H.; Welch, Andreanna J.; Fleischer, Robert C.; Gandhi, Hasand; Southon, John R.; Stafford, Thomas W.; Penniman, Jay F.; Hu, Darcy; Duvall, Fern P.; James, Helen F.

    2013-01-01

    Human exploitation of marine ecosystems is more recent in oceanic than near shore regions, yet our understanding of human impacts on oceanic food webs is comparatively poor. Few records of species that live beyond the continental shelves date back more than 60 y, and the sheer size of oceanic regions makes their food webs difficult to study, even in modern times. Here, we use stable carbon and nitrogen isotopes to study the foraging history of a generalist, oceanic predator, the Hawaiian petrel (Pterodroma sandwichensis), which ranges broadly in the Pacific from the equator to near the Aleutian Islands. Our isotope records from modern and ancient, radiocarbon-dated bones provide evidence of over 3,000 y of dietary stasis followed by a decline of ca. 1.8‰ in δ15N over the past 100 y. Fishery-induced trophic decline is the most likely explanation for this sudden shift, which occurs in genetically distinct populations with disparate foraging locations. Our isotope records also show that coincident with the apparent decline in trophic level, foraging segregation among petrel populations decreased markedly. Because variation in the diet of generalist predators can reflect changing availability of their prey, a foraging shift in wide-ranging Hawaiian petrel populations suggests a relatively rapid change in the composition of oceanic food webs in the Northeast Pacific. Understanding and mitigating widespread shifts in prey availability may be a critical step in the conservation of endangered marine predators such as the Hawaiian petrel. PMID:23671094

  4. Millennial-scale isotope records from a wide-ranging predator show evidence of recent human impact to oceanic food webs.

    PubMed

    Wiley, Anne E; Ostrom, Peggy H; Welch, Andreanna J; Fleischer, Robert C; Gandhi, Hasand; Southon, John R; Stafford, Thomas W; Penniman, Jay F; Hu, Darcy; Duvall, Fern P; James, Helen F

    2013-05-28

    Human exploitation of marine ecosystems is more recent in oceanic than near shore regions, yet our understanding of human impacts on oceanic food webs is comparatively poor. Few records of species that live beyond the continental shelves date back more than 60 y, and the sheer size of oceanic regions makes their food webs difficult to study, even in modern times. Here, we use stable carbon and nitrogen isotopes to study the foraging history of a generalist, oceanic predator, the Hawaiian petrel (Pterodroma sandwichensis), which ranges broadly in the Pacific from the equator to near the Aleutian Islands. Our isotope records from modern and ancient, radiocarbon-dated bones provide evidence of over 3,000 y of dietary stasis followed by a decline of ca. 1.8‰ in δ(15)N over the past 100 y. Fishery-induced trophic decline is the most likely explanation for this sudden shift, which occurs in genetically distinct populations with disparate foraging locations. Our isotope records also show that coincident with the apparent decline in trophic level, foraging segregation among petrel populations decreased markedly. Because variation in the diet of generalist predators can reflect changing availability of their prey, a foraging shift in wide-ranging Hawaiian petrel populations suggests a relatively rapid change in the composition of oceanic food webs in the Northeast Pacific. Understanding and mitigating widespread shifts in prey availability may be a critical step in the conservation of endangered marine predators such as the Hawaiian petrel. PMID:23671094

  5. Submarine thermal springs on the Galapagos Rift

    USGS Publications Warehouse

    Corliss, J.B.; Dymond, J.; Gordon, L.I.; Edmond, J.M.; Von Herzen, R. P.; Ballard, Richard D.; Green, K.; Williams, D.; Bainbridge, A.; Crane, K.; Van Andel, T. H.

    1979-01-01

    The submarine hydrothermal activity on and near the Galápagos Rift has been explored with the aid of the deep submersible Alvin. Analyses of water samples from hydrothermal vents reveal that hydrothermal activity provides significant or dominant sources and sinks for several components of seawater; studies of conductive and convective heat transfer suggest that two-thirds of the heat lost from new oceanic lithosphere at the Galápagos Rift in the first million years may be vented from thermal springs, predominantly along the axial ridge within the rift valley. The vent areas are populated by animal communities. They appear to utilize chemosynthesis by sulfur-oxidizing bacteria to derive their entire energy supply from reactions between the seawater and the rocks at high temperatures, rather than photosynthesis

  6. Submarine thermal sprirngs on the galapagos rift.

    PubMed

    Corliss, J B; Dymond, J; Gordon, L I; Edmond, J M; von Herzen, R P; Ballard, R D; Green, K; Williams, D; Bainbridge, A; Crane, K; van Andel, T H

    1979-03-16

    The submarine hydrothermal activity on and near the Galápagos Rift has been explored with the aid of the deep submersible Alvin. Analyses of water samples from hydrothermal vents reveal that hydrothermal activity provides significant or dominant sources and sinks for several components of seawater; studies of conductive and convective heat transfer suggest that two-thirds of the heat lost from new oceanic lithosphere at the Galápagos Rift in the first million years may be vented from thermal springs, predominantly along the axial ridge within the rift valley. The vent areas are populated by animal communities. They appear to utilize chemosynthesis by sulfur-oxidizing bacteria to derive their entire energy supply from reactions between the seawater and the rocks at high temperatures, rather than photosynthesis. PMID:17776033

  7. Shear Wave Splitting Beneath the Galapagos Archipelago

    NASA Astrophysics Data System (ADS)

    Fontaine, F. R.; Burkett, P. G.; Hooft, E. E.; Toomey, D. R.; Solomon, S. C.; Silver, P. G.

    2004-12-01

    We report measurements of teleseismic shear wave splitting in the Galápagos Archipelago. The inferred lateral variations in azimuthal anisotropy allow us to examine the dynamics of an evolving hotspot-ridge system. The data are from SKS and SKKS phases, as well as S waves from deep sources, recorded by a relatively dense network of 10 portable broadband seismometers deployed from 1999 to 2003 for the IGUANA (Imaging Galápagos Upwelling and Neotectonics of the Archipelago) experiment and from the GSN broadband station in Santa Cruz (PAYG). We find a delay time between fast and slow shear waves of 0.4 to 0.9 s and fast polarization directions of N85-90° E beneath five stations at the leading and southern edge of the archipelago. Despite clear seismic signals, we did not find any anisotropy at the six stations located in the interior of the archipelago. For those stations that show shear wave splitting, there is an increase in the delay time toward the expected location of the Galápagos hotspot at the western edge of the archipelago. With the exception of Española, fast polarization directions (N85-90° E) are close to the current direction of absolute plate motion of the overlying Nazca plate (N91° E). The lack of azimuthal anisotropy in the interior of the archipelago is interpreted as an absence of strongly oriented mantle fabric beneath these stations. The apparent isotropy in this dynamic region, where we expect considerable mantle strain, is surprising. It is not likely that the olivine a-axis is oriented vertically beneath the interior of the archipelago as the Galápagos plume is thought to lie at the western edge. It is also unlikely that there are two layers of perpendicularly-oriented anisotropy which are solely confined to the center of the archipelago. However, there appears to be some correlation between the region of apparent isotropy and a zone of anomalously low upper mantle velocities imaged beneath Santiago and Marchena from surface waves by Villagomez and others, though the low-velocity region is spatially more confined. This pattern suggests that the presence of melt in the upper mantle may weaken the effects of fabric on shear wave splitting, as suggested by Holtzman and others. An alternative explanation is that the flow field in the near ridge setting is complex, resulting in apparent isotropy. Due to the very young lithospheric age and to the effect of both the neighboring ridge and Galápagos hotspot, the lithosphere thickness is likely thinner than 40 km. Therefore no more than about 40% of the recorded delay time could originate from the lithosphere. We propose that the splitting pattern in the Galápagos Archipelago may be the result of plate drag and frozen lithospheric anisotropy which, beneath the center of the archipelago, is weakened by the presence of melt in the upper mantle.

  8. Darwin's Galapagos finches in modern biology.

    PubMed

    Abzhanov, Arhat

    2010-04-12

    One of the classic examples of adaptive radiation under natural selection is the evolution of 15 closely related species of Darwin's finches (Passeriformes), whose primary diversity lies in the size and shape of their beaks. Since Charles Darwin and other members of the Beagle expedition collected these birds on the Galápagos Islands in 1835 and introduced them to science, they have been the subjects of intense research. Many biology textbooks use Darwin's finches to illustrate a variety of topics of evolutionary theory, such as speciation, natural selection and niche partitioning. Today, as this Theme Issue illustrates, Darwin's finches continue to be a very valuable source of biological discovery. Certain advantages of studying this group allow further breakthroughs in our understanding of changes in recent island biodiversity, mechanisms of speciation and hybridization, evolution of cognitive behaviours, principles of beak/jaw biomechanics as well as the underlying developmental genetic mechanisms in generating morphological diversity. Our objective was to bring together some of the key workers in the field of ecology and evolutionary biology who study Darwin's finches or whose studies were inspired by research on Darwin's finches. Insights provided by papers collected in this Theme Issue will be of interest to a wide audience.

  9. Population divergence and gene flow in an endangered and highly mobile seabird.

    PubMed

    Welch, A J; Fleischer, R C; James, H F; Wiley, A E; Ostrom, P H; Adams, J; Duvall, F; Holmes, N; Hu, D; Penniman, J; Swindle, K A

    2012-07-01

    Seabirds are highly vagile and can disperse up to thousands of kilometers, making it difficult to identify the factors that promote isolation between populations. The endemic Hawaiian petrel (Pterodroma sandwichensis) is one such species. Today it is endangered, and known to breed only on the islands of Hawaii, Maui, Lanai and Kauai. Historical records indicate that a large population formerly bred on Molokai as well, but this population has recently been extirpated. Given the great dispersal potential of these petrels, it remains unclear if populations are genetically distinct and which factors may contribute to isolation between them. We sampled petrels from across their range, including individuals from the presumably extirpated Molokai population. We sequenced 524 bp of mitochondrial DNA, 741 bp from three nuclear introns, and genotyped 18 microsatellite loci in order to examine the patterns of divergence in this species and to investigate the potential underlying mechanisms. Both mitochondrial and nuclear data sets indicated significant genetic differentiation among all modern populations, but no differentiation was found between historic samples from Molokai and modern birds from Lanai. Population-specific nonbreeding distribution and strong natal philopatry may reduce gene flow between populations. However, the lack of population structure between extirpated Molokai birds and modern birds on Lanai indicates that there was substantial gene flow between these populations and that petrels may be able to overcome barriers to dispersal prior to complete extirpation. Hawaiian petrel populations could be considered distinct management units, however, the dwindling population on Hawaii may require translocation to prevent extirpation in the near future. PMID:22434012

  10. Radar study of seabirds and bats on windward Hawai'i

    USGS Publications Warehouse

    Reynolds, M.H.; Cooper, B.A.; Day, R.H.

    1997-01-01

    Modified marine surveillance radar was used to study the presence/ absence, abundance, and flight activity of four nocturnal species: Hawaiian darkrumped petrel [Pterodroma phaeopygia sandwichensis (Ridgeway)], Newell's shearwater [Puffinus auricularis newelli (Henshaw)], Band-rumped storm-petrel [Oceanodroma castro (Harcourt)], and Hawaiian hoary bat (Lasiurus cinereus semotus Sanborn & Crespo). Hawaiian seabirds were recorded flying to or from inland nesting colonies at seven sampling sites on the windward side of the island of Hawai'i. In total, 527 radar "targets" identified as petrel or shearwater-type on the basis of speed, flight behavior, and radar signal strength were observed during eight nights of sampling. Mean movement rates (targets per minute) for seabird targets were 0.1, 0.1, 0.3, 3.8, 0.9, and 2.2 for surveys at Kahakai, Kapoho, Mauna Loa, Pali Uli, Pu'ulena Crater, and Waipi'o Valley, respectively. Two percent of the petrel and shearwater-type targets detected on radar were confirmed visually or aurally. Flight paths for seabird targets showed strong directionality at six sampling sites. Mean flight speed for seabird targets (n = 524) was 61 km/hr for all survey areas. Peak detection times for seabirds were from 0430 to 0530 hours for birds flying to sea and 2000 to 2150 hours for birds returning to colonies. Most inland, low-elevation sampling sites could not be surveyed reliably for seabirds during the evening activity periods because of radar interference from insects and rapidly flying bats. At those inland sites predawn sampling was the best time for using radar to detect Hawaiian seabirds moving seaward. Hawaiian hoary bats were recorded at eight sampling sites. Eighty-six to 89 radar targets that exhibited erratic flight behavior were identified as "batlike" targets; 17% of these batlike radar targets were confirmed visually. Band-rumped storm-petrels were not identified during our surveys.

  11. Population divergence and gene flow in an endangered and highly mobile seabird

    USGS Publications Warehouse

    Welch, A. J.; Fleischer, R. C.; James, H. F.; Wiley, A. E.; Ostrom, P. H.; Adams, J.; Duvall, F.; Holmes, N.; Hu, D.; Penniman, J.; Swindle, K. A.

    2012-01-01

    Seabirds are highly vagile and can disperse up to thousands of kilometers, making it difficult to identify the factors that promote isolation between populations. The endemic Hawaiian petrel (Pterodroma sandwichensis) is one such species. Today it is endangered, and known to breed only on the islands of Hawaii, Maui, Lanai and Kauai. Historical records indicate that a large population formerly bred on Molokai as well, but this population has recently been extirpated. Given the great dispersal potential of these petrels, it remains unclear if populations are genetically distinct and which factors may contribute to isolation between them. We sampled petrels from across their range, including individuals from the presumably extirpated Molokai population. We sequenced 524 bp of mitochondrial DNA, 741 bp from three nuclear introns, and genotyped 18 microsatellite loci in order to examine the patterns of divergence in this species and to investigate the potential underlying mechanisms. Both mitochondrial and nuclear data sets indicated significant genetic differentiation among all modern populations, but no differentiation was found between historic samples from Molokai and modern birds from Lanai. Population-specific nonbreeding distribution and strong natal philopatry may reduce gene flow between populations. However, the lack of population structure between extirpated Molokai birds and modern birds on Lanai indicates that there was substantial gene flow between these populations and that petrels may be able to overcome barriers to dispersal prior to complete extirpation. Hawaiian petrel populations could be considered distinct management units, however, the dwindling population on Hawaii may require translocation to prevent extirpation in the near future.

  12. Robert Wartenberg: stormy petrel of neurology; rebel of book reviewers.

    PubMed

    Boshes, L D

    1996-12-01

    This "Sherlock Holmes" in the discipline of neurology, always searching for truth accuracy and dependability of researcher, clinician or writer, advanced his endowment into book reviewing. His acrid criticism was accurate, for the succeeding edition always embodied all recommendations, but at all times everyone benefited from the Wartenberg warmth, for he never made enemies with his microscopic scrutiny of facts in his unique but complete review of a tome. PMID:11618749

  13. Contemporary and historical separation of transequatorial migration between genetically distinct seabird populations.

    PubMed

    Rayner, Matt J; Hauber, Mark E; Steeves, Tammy E; Lawrence, Hayley A; Thompson, David R; Sagar, Paul M; Bury, Sarah J; Landers, Todd J; Phillips, Richard A; Ranjard, Louis; Shaffer, Scott A

    2011-01-01

    Pelagic seabirds are highly mobile, reducing the likelihood of allopatric speciation where disruption of gene flow between populations is caused by physically insurmountable, extrinsic barriers. Spatial segregation during the non-breeding season appears to provide an intrinsic barrier to gene flow among seabird populations that otherwise occupy nearby or overlapping regions during breeding, but how this is achieved remains unclear. Here we show that the two genetically distinct populations of Cook's petrel (Pterodroma cookii) exhibit transequatorial separation of non-breeding ranges at contemporary (ca. 2-3 yrs) and historical (ca. 100 yrs) time scales. Segregation during the non-breeding season per se appears as an unlikely barrier to gene flow. Instead we provide evidence that habitat specialization during the non-breeding season is associated with breeding asynchrony which, in conjunction with philopatry, restricts gene flow. Habitat specialization during breeding and non-breeding likely promotes evolutionary divergence between these two populations via local adaptation. PMID:21629265

  14. Isotopic characterization of flight feathers in two pelagic seabirds: Sampling strategies for ecological studies

    USGS Publications Warehouse

    Wiley, Anne E.; Ostrom, Peggy H.; Stricker, Craig A.; James, Helen F.; Gandhi, Hasand

    2010-01-01

    We wish to use stable-isotope analysis of flight feathers to understand the feeding behavior of pelagic seabirds, such as the Hawaiian Petrel (Pterodroma sandwichensis) and Newell’s Shearwater (Puffinus auricularis newelli). Analysis of remiges is particularly informative because the sequence and timing of remex molt are often known. The initial step, reported here, is to obtain accurate isotope values from whole remiges by means of a minimally invasive protocol appropriate for live birds or museum specimens. The high variability observed in D13C and D15N values within a feather precludes the use of a small section of vane. We found the average range within 42 Hawaiian Petrel remiges to be 1.3‰ for both D13C and D15N and that within 10 Newell’s Shearwater remiges to be 1.3‰ and 0.7‰ for D13C and D15N, respectively. The D13C of all 52 feathers increased from tip to base, and the majority of Hawaiian Petrel feathers showed an analogous trend in D15N. Although the average range of DD in 21 Hawaiian Petrel remiges was 11‰, we found no longitudinal trend. We discuss influences of trophic level, foraging location, metabolism, and pigmentation on isotope values and compare three methods of obtaining isotope averages of whole feathers. Our novel barb-sampling protocol requires only 1.0 mg of feather and minimal preparation time. Because it leaves the feather nearly intact, this protocol will likely facilitate obtaining isotope values from remiges of live birds and museum specimens. As a consequence, it will help expand the understanding of historical trends in foraging behavior

  15. Spring-time distributions of migratory marine birds in the southern California Current: Oceanic eddy associations and coastal habitat hotspots over 17 years

    NASA Astrophysics Data System (ADS)

    Yen, P. P. W.; Sydeman, W. J.; Bograd, S. J.; Hyrenbach, K. D.

    2006-02-01

    We used a 17-year time series of shipboard observations to address the hypothesis that marine birds associate with persistent hydrographic features in the southern California Current System (CCS). Overall, approximately 27,000 km of ocean habitat were surveyed, averaging 1600 km per cruise. We identified mesoscale features (eddy centers and the core of the California Current), based on dynamic height anomalies, and considered habitat associations for seven migratory seabird species: black-footed albatross ( Phoebastria nigripes), Cook's petrel ( Pterodroma cookii), Leach's storm-petrel ( Oceanodroma leucorhoa), dark shearwaters (mainly sooty shearwater Puffinus griseus, with a few short-tailed shearwaters Puffinus tenuirostris), northern fulmar ( Fulmarus glacialis), red phalarope ( Phalaropus fulicaria), and red-necked phalarope ( Phalaropus lobatus). We explored associations (presence/absence and density relationships) of marine birds with mesoscale features (eddies, current jet) and metrics of primary productivity (chlorophyll a and nitrate concentrations). Mesoscale eddies were consistently identified in the study region, but were spatially and temporally variable. The resolved eddies were large-scale features associated with meanders of the equatorward-flowing California Current. Cook's petrel was found offshore with no specific habitat affinities. Black-footed albatross, red phalarope, and Leach's storm petrel were found in association with offshore eddies and/or the core of the California Current, but the functional relationship for these species varied, possibly reflecting differences in flight capabilities. The more coastal species, including the shearwaters, fulmar, and red-necked phalarope, were positively associated with proxies of primary productivity. Of the hydrographic habitats considered, the upwelling region of Point Conception appears to be an important "hotspot" of sustained primary production and marine bird concentrations. Point Conception and

  16. Trace elements in three marine birds breeding on Reunion Island (Western Indian ocean): part 1-factors influencing their bioaccumulation.

    PubMed

    Kojadinovic, J; Le Corre, M; Cosson, R P; Bustamante, P

    2007-04-01

    This work aimed to use seabirds as bioindicators of trace element levels in the tropical waters and food webs of the Western Indian Ocean. The accumulation patterns of selected toxic (Cd and Hg) and essential (Cu, Fe, Mn, Se, and Zn) elements were determined in liver, kidney, and pectoral muscle of 162 marine birds belonging to 3 species collected in Reunion Island between 2002 and 2004. These pelagic seabirds belong to the following species: Barau's Petrel (Pterodroma baraui), Audubon's Shearwater (Puffinus lherminieri bailloni), and White-Tailed Tropicbird (Phaethon lepturus). Hg levels were also measured in breast feathers. Highest mean kidney Cd and liver Hg levels (respectively, 27.79 +/- 13.78 microg x g (-1) dry weight (dw) and 24.31 +/- 14.13 microg x g (-1) dw) were found in the squid-eating Barau's Petrel. Barau's Petrel feather Hg levels fell in the range of 0.6 to 2.7 microg x g(-1) dw previously reported for other petrels and shearwaters. The values of the other elements were also in the same range as those previously reported in the published literature concerning related seabirds, although Se and Zn burdens in the Reunion birds were among the highest values. Levels of Zn, Fe, and, to a lesser extent, Cu appeared to be regulated in seabird tissues. Uptake and pathways of metabolism and storage seemed to be similar for the five essential elements. The reproductive status of the bird did not seem to affect element levels, which, moreover, were not significantly different between male and female birds. However, trace elements in sampled birds varied according to the tissue considered, the age of the animal, and its species. Diet was seemingly a major influencing factor. Health status also appeared to have an impact on element levels. PMID:17165110

  17. Mercury in seabird feathers: insight on dietary habits and evidence for exposure levels in the western Indian Ocean.

    PubMed

    Kojadinovic, Jessica; Bustamante, Paco; Churlaud, Carine; Cosson, Richard P; Le Corre, Matthieu

    2007-10-01

    Breast feathers were used to estimate mercury levels in six marine birds nesting in the tropical western Indian Ocean, i.e. Sooty Tern (Sterna fuscata), Brown Noddy (Anous stolidus), Lesser Noddy (Anous tenuirostris), Audubon Shearwater (Puffinus lherminieri bailloni), Barau's Petrel (Pterodroma baraui) and the White-tailed Tropicbird (Phaethon lepturus). Juveniles consistently showed lower plumage mercury than adults. The lowest mean level was noted in juvenile Sooty Terns from the Glorioso Archipelago (0.05 microg g(-1)). The highest levels were obtained for adult Barau's Petrels from Reunion Island (0.96 microg g(-1)). An inter-site analysis of Sooty Tern showed higher mercury levels in birds nesting on Juan de Nova Island. Levels were low in comparison with values reported in the plumage of seabirds worldwide. The potential impacts of the size, the type (fish/cephalopod) and the origin (epi-/meso-pelagic) of prey on mercury intake in birds are discussed. Although the diet composition of individuals within a species appeared to be quite variable, combining results on mercury levels with common knowledge of each species allowed additional information on their dietary and foraging habits to be unraveled. PMID:17659323

  18. Novel area serving binocular vision in the retinae of procellariiform seabirds.

    PubMed

    Hayes, B; Martin, G R; Brooke, M de L

    1991-01-01

    Procellariiforms are pelagic seabirds which fly close to the sea surface and feed either by taking items from the surface or by shallow diving. The retinal ganglion cells in five species (Manx shearwater, Puffinus puffinus, Kerguelen petrel, Pterodroma brevirostris, great shearwater, Puffinus gravis, broad-billed prion, Pachyptila vittata, and common diving petrel, Pelecanoides urinatrix) were examined by Nissl staining and also by silver staining in the case of the common diving petrel. In all five species, a well-defined region in the dorsotemporal retina, close to the ora, was identified. This region is characterized by the presence of ganglion cells which are both regularly arrayed and larger than those found in the rest of the retina. These cells also have a large dendritic field of sparsely branched dendrites with much dendritic overlap between cells, thick axons, and dendrites confined to the proximal inner plexiform layer. Morphologically, they appear similar to the alpha cells of the retina in cats. It is suggested that the region containing these cells should be regarded as a retinal area, and the name area giganto cellularis is proposed. In the Manx shearwater, it is found that this novel area projects visually into the binocular field below the bill. Unlike previously described areas in avian retinae, it seems that this novel area is not concerned with high spatial resolution. It may function in the detection of objects on the sea surface and/or be concerned with the detection of the actual sea surface as a bird flies low over it. PMID:2054586

  19. Understanding Magmatic Plumbing System Dynamics at Fernandina Island, Galapagos

    NASA Astrophysics Data System (ADS)

    Varga, K. C.; McGuire, M.; Geist, D.; Harpp, K. S.

    2015-12-01

    Fernandina is the most active Galápagos volcano, and is located closest to the seismically defined hotspot. Allan and Simkin (2000) observed that the subaerial edifice is constructed of homogeneous basalts (Mg# = 49 ± 2) with highly variable plagioclase phenocryst contents and sparse olivine. Geist et al. (2006) proposed a magmatic plumbing system in which the volcano is supplied by interconnected sills, the shallowest of which is density-stratified: olivine and pyroxene are concentrated at greater depths, whereas less dense plagioclase mush is higher in the sill. Consequently, olivine-rich lava erupts laterally during submarine events, but plagioclase-rich lava supplies subaerial vents. To test this hypothesis, we examine lavas erupted in 1995, 2005, and 2009. These SW flank eruptions emerged alternatively from en echelon radial fissures on the lower flanks and circumferential fissures near the caldera rim. The 1995 radial fissure unzipped downslope and then formed a cone 4 km from the coast, sending flows to the ocean. In 2005, circumferential fissures erupted five flows south of the 1995 fissure. As in 1995, the 2009 fissures opened down the SW flank before focusing to a cone near the 1995 vents, producing 6 km-long flows that also reached the ocean. By correlating plagioclase crystal size distribution and morphologies with single event chronological sequences, we examine Fernandina's magmatic plumbing system. Modal plagioclase in 1995 lava decreases (20% to <5%) throughout the middle eruptive phase. Early 2005 samples are nearly aphyric (Chadwick et al., 2010), with 1-2% plagioclase. The 2009 eruption has reduced plagioclase, similar to mid-1995 samples. Preliminary observations suggest that less plagioclase-rich mush is being flushed out during early-to-medial event sequences, whereas plag phenocrysts are transported more during later phases. Plausible plumbing dynamics suggest a zone of plagioclase-rich mush that is eroded and incorporated into radial fissure eruptions.

  20. Coevolution in the Galapagos: An Example for the Biology Classroom.

    ERIC Educational Resources Information Center

    Biggs, Alton L.

    1990-01-01

    Several examples of coevolution which can be used in biology classes are presented. Discussed are evolutionary processes in general, giant cacti, and reptile and cacti association. The effects of human interference are briefly described. (CW)

  1. From Galapagos to the labs: Darwinian medicine and epilepsy today.

    PubMed

    Scorza, Fulvio A; Cysneiros, Roberta M; Terra, Vera C; Arida, Ricardo M; Scorza, Carla A; Cavalheiro, Esper A

    2009-11-01

    In 1991, a mummy frozen in ice was found by climbers in the Tyrolean Alps. Otzi the Iceman has since been studied in the light of evolutionary explanations for diseases. This year, which marks Charles Darwin's 200th birthday and the 150th anniversary of his publication On the Origin of Species, should re-ignite discussion of the importance of the correlation between nutritional diet and diseases. Epilepsy is one of the commonest diseases in the world. Individuals with epilepsy are at higher risk of death than the general population, and sudden unexpected death (SUDEP) is the most important direct epilepsy-related cause of death. A number of factors may influence the risk for SUDEP. Along these lines, several studies have demonstrated that polyunsaturated (omega-3) fatty acids may reduce the risk of cardiovascular mortality, and diminish neuronal excitability. Also, omega-3 fatty acids may decrease seizure frequency, contributing to the reduction of SUDEP risk. Reconstruction of the nutritional patterns of Stone Age humans and optimal human nutrition in the present may be relevant to the prevention and treatment of chronic diseases such as epilepsy and the catastrophic evolution into epilepsy refractoriness and SUDEP.

  2. Unexpected hydrogen isotope variation in oceanic pelagic seabirds

    USGS Publications Warehouse

    Ostrom, Peggy H.; Wiley, Anne E.; Rossman, Sam; Stricker, Craig A.; James, Helen F.

    2014-01-01

    Hydrogen isotopes have significantly enhanced our understanding of the biogeography of migratory animals. The basis for this methodology lies in predictable, continental patterns of precipitation δD values that are often reflected in an organism's tissues. δD variation is not expected for oceanic pelagic organisms whose dietary hydrogen (water and organic hydrogen in prey) is transferred up the food web from an isotopically homogeneous water source. We report a 142% range in the δD values of flight feathers from the Hawaiian petrel (Pterodroma sandwichensis), an oceanic pelagic North Pacific species, and inquire about the source of that variation. We show δD variation between and within four other oceanic pelagic species: Newell's shearwater (Puffinus auricularis newellii), Black-footed albatross (Phoebastria nigripes), Laysan albatross (Phoebastria immutabilis) and Buller's shearwater (Puffinus bulleri). The similarity between muscle δD values of hatch-year Hawaiian petrels and their prey suggests that trophic fractionation does not influence δD values of muscle. We hypothesize that isotopic discrimination is associated with water loss during salt excretion through salt glands. Salt load differs between seabirds that consume isosmotic squid and crustaceans and those that feed on hyposmotic teleost fish. In support of the salt gland hypothesis, we show an inverse relationship between δD and percent teleost fish in diet for three seabird species. Our results demonstrate the utility of δD in the study of oceanic consumers, while also contributing to a better understanding of δD systematics, the basis for one of the most commonly utilized isotope tools in avian ecology.

  3. Unexpected hydrogen isotope variation in oceanic pelagic seabirds.

    PubMed

    Ostrom, Peggy H; Wiley, Anne E; Rossman, Sam; Stricker, Craig A; James, Helen F

    2014-08-01

    Hydrogen isotopes have significantly enhanced our understanding of the biogeography of migratory animals. The basis for this methodology lies in predictable, continental patterns of precipitation δD values that are often reflected in an organism's tissues. δD variation is not expected for oceanic pelagic organisms whose dietary hydrogen (water and organic hydrogen in prey) is transferred up the food web from an isotopically homogeneous water source. We report a 142‰ range in the δD values of flight feathers from the Hawaiian petrel (Pterodroma sandwichensis), an oceanic pelagic North Pacific species, and inquire about the source of that variation. We show δD variation between and within four other oceanic pelagic species: Newell's shearwater (Puffinus auricularis newellii), Black-footed albatross (Phoebastria nigripes), Laysan albatross (Phoebastria immutabilis) and Buller's shearwater (Puffinus bulleri). The similarity between muscle δD values of hatch-year Hawaiian petrels and their prey suggests that trophic fractionation does not influence δD values of muscle. We hypothesize that isotopic discrimination is associated with water loss during salt excretion through salt glands. Salt load differs between seabirds that consume isosmotic squid and crustaceans and those that feed on hyposmotic teleost fish. In support of the salt gland hypothesis, we show an inverse relationship between δD and percent teleost fish in diet for three seabird species. Our results demonstrate the utility of δD in the study of oceanic consumers, while also contributing to a better understanding of δD systematics, the basis for one of the most commonly utilized isotope tools in avian ecology. PMID:24989118

  4. Trace elements in three marine birds breeding on Reunion Island (Western Indian ocean): part 2-factors influencing their detoxification.

    PubMed

    Kojadinovic, J; Bustamante, P; Le Corre, M; Cosson, R P

    2007-04-01

    Seabird tissues collected between 2002 and 2004 from Barau's Petrel (Pterodroma baraui), Audubon's Shearwater (Puffinus lherminieri bailloni), and White-Tailed Trop icbird (Phaethon lepturus) colonies on Reunion Island were analyzed for metallothioneins (MTs) and trace element content. The subcellular distribution between soluble and insoluble fractions of Cd, Cu, Fe, Mn, Se, and Zn was determined in liver and kidney. In both, the soluble fraction of the cell concentrated most of the Cd and Se, whereas Fe, Mn, and Zn were preferentially accumulated in the insoluble fraction. The distribution of these elements varied with the tissue, age of the bird, and species. Furthermore, the distributions of Fe and Mn were somewhat influenced by the bird's physical condition. MT levels were measured in the soluble fraction after heat denaturation. The levels of these proteins varied from 5.5 +/- 2.7 mg x g(-1) dry weight (dw) to 11.4 +/- 6.2 mg x g(-1) dw depending on the species and the tissue considered. MT levels were significantly different between liver and kidney only in the White-Tailed Tropicbird. In the three species, MT levels in kidney were significantly higher in adult than juvenile birds. The bird's weight also had an influence on hepatic and renal MT levels, but not the sex nor the reproductive status. The implication of MTs in Cu and Zn homeostasis and Cd and Hg detoxification are discussed. In addition, clues on Hg regulation by Se were found, especially in Barau's Petrel, where the levels of these two elements were significantly correlated. PMID:17354039

  5. Diet of feral cats in Hawai'i Volcanoes National Park

    USGS Publications Warehouse

    Hess, S.C.; Hansen, H.; Nelson, D.; Swift, R.; Banko, P.C.

    2007-01-01

    We documented the diet of feral cats by analysing the contents of 42 digestive tracts from Kilauea and Mauna Loa in Hawai'i Volcanoes National Park. Small mammals, invertebrates, and birds were the most common prey types consumed by feral cats. Birds occurred in 27.8-29.2% of digestive tracts. The total number of bird, small mammal, and invertebrate prey differed between Kilauea and Mauna Loa. On Mauna Loa, significantly more (89%) feral cats consumed small mammals, primarily rodents, than on Kilauea Volcano (50%). Mice (Mus musculus) were the major component of the feral cat diet on Mauna Loa, whereas Orthoptera were the major component of the diet on Kilauea. We recovered a mandible set, feathers, and bones of an endangered Hawaiian Petrel (Pterodroma sandwichensis) from a digestive tract from Mauna Loa. This specimen represents the first well-documented endangered seabird to be recovered from the digestive tract of a feral cat in Hawai'i and suggests that feral cats prey on this species.

  6. Videographic evidence of endangered species depredation by feral cat

    USGS Publications Warehouse

    Judge, Seth; Lippert, Jill S.; Misajon, Kathleen; Hu, Darcy; Hess, Steven C.

    2012-01-01

    Feral cats (Felis cafus) have long been implicated as nest predators of endangered 'Ua'u (Hawaiian Petrel; Pterodroma sandwichensis) on Hawaii Island, but until recently, visual confirmation has been limited by available technology. 'Ua'u nest out of view, deep inside small cavities, on alpine lava flows. During the breeding seasons of 2007 and 2008, we monitored known burrows within Hawai'i Volcanoes National Park. Digital infrared video cameras assisted in determining the breeding behaviour and nesting success at the most isolated of burrows. With 7 cameras, we collected a total of 819 videos and 89 still photographs of adult and nestling 'Ua'u at 14 burrows. Videos also confirmed the presence of rats (Rattus spp.) at 2 burrows, 'Ōmao (Myadestes obscurus) at 8 burrows, and feral cats at 6 burrows. A sequence of videos showed a feral cat taking a downy 'Ua'u chick from its burrow, representing the first direct evidence of 'Ua'u depredation by feral cat in Hawai'i. This technique provides greater understanding of feral cat behaviour in 'Ua'u colonies, which may assist in the development of more targeted management strategies to reduce nest predation on endangered insular bird species.

  7. New genetic approach to detecting individuals of rare and endangered species.

    PubMed

    Lawrence, Hayley A; Taylor, Graeme A; Crockett, David E; Millar, Craig D; Lambert, David M

    2008-10-01

    Many rare and endangered species are difficult to locate, observe, and study. Consequently, many individuals, breeding pairs, and even populations of such species could remain undetected. Genetic markers can potentially be used to detect the existence of undiscovered individuals and populations, and we propose a method to do so that requires 3 conditions. First, sampling of the known population(s) of the target species must be comprehensive. Second, the species must display a reasonable level of philopatry and genetic structuring. Third, individuals must be able to be caught outside of breeding locations (e.g., at courtship or feeding areas, in flight), and the level of recapture must be reasonably high. We applied our method to the Chatham Island Taiko (Pterodroma magentae), one of the world's most endangered seabirds. We sequenced the Taiko mitochondrial cytochrome b gene and both copies of a fragment of the duplicated domain I of the control region. Twenty-one haplotypes were revealed, including 4 (19%) not found in birds at known burrows. These results suggest there are more burrow groups yet to be located. The species is a pelagic gadfly petrel that inhabits land only in the breeding season during which it is nocturnal and nests in burrows. Taiko burrows are situated in dense forest in a remote area of Chatham Island, and are consequently difficult to locate and study. It is important that all Taiko burrows be discovered to enable monitoring and protection of the birds from exotic predators. PMID:18717692

  8. Ancient genetic variation in one of the world's rarest seabirds.

    PubMed

    Lawrence, H A; Scofield, R P; Crockett, D E; Millar, C D; Lambert, D M

    2008-12-01

    The Chatham Island Taiko (Tchaik, Pterodroma magentae) is one of the world's rarest seabirds. In the past there were millions of breeding pairs of Taiko and it was the most abundant burrowing petrel on Chatham Island. The present population consists of just 120-150 birds, including only 8-15 breeding pairs. Surprisingly high genetic variation was revealed by DNA sequencing of almost every known adult Taiko (N=90). Given the massive population decline, genetic variation may have been even larger in the past. Therefore, we investigated past genetic diversity by sequencing regions of the mitochondrial cytochrome b gene in 44 ancient Taiko bones. We identified a total of 12 haplotypes in Taiko. Eight haplotypes were revealed in the ancient DNA: four were unique to the bones and four corresponded to those found in the modern Taiko population. Surprisingly, despite the critically endangered status of the Taiko, no significant reduction in mitochondrial DNA haplotype diversity was observed between ancient samples (N=44) and modern adult Taiko (N=90). The modern population may have however lost four haplotypes present in the ancient populations. PMID:19018271

  9. New genetic approach to detecting individuals of rare and endangered species.

    PubMed

    Lawrence, Hayley A; Taylor, Graeme A; Crockett, David E; Millar, Craig D; Lambert, David M

    2008-10-01

    Many rare and endangered species are difficult to locate, observe, and study. Consequently, many individuals, breeding pairs, and even populations of such species could remain undetected. Genetic markers can potentially be used to detect the existence of undiscovered individuals and populations, and we propose a method to do so that requires 3 conditions. First, sampling of the known population(s) of the target species must be comprehensive. Second, the species must display a reasonable level of philopatry and genetic structuring. Third, individuals must be able to be caught outside of breeding locations (e.g., at courtship or feeding areas, in flight), and the level of recapture must be reasonably high. We applied our method to the Chatham Island Taiko (Pterodroma magentae), one of the world's most endangered seabirds. We sequenced the Taiko mitochondrial cytochrome b gene and both copies of a fragment of the duplicated domain I of the control region. Twenty-one haplotypes were revealed, including 4 (19%) not found in birds at known burrows. These results suggest there are more burrow groups yet to be located. The species is a pelagic gadfly petrel that inhabits land only in the breeding season during which it is nocturnal and nests in burrows. Taiko burrows are situated in dense forest in a remote area of Chatham Island, and are consequently difficult to locate and study. It is important that all Taiko burrows be discovered to enable monitoring and protection of the birds from exotic predators.

  10. Will the effects of sea-level rise create ecological traps for Pacific Island seabirds?

    USGS Publications Warehouse

    Reynolds, Michelle H.; Courtot, Karen; Berkowitz, Paul; Storlazzi, Curt; Moore, Janet; Flint, Elizabeth

    2015-01-01

    More than 18 million seabirds nest on 58 Pacific islands protected within vast U.S. Marine National Monuments (1.9 million km2). However, most of these seabird colonies are on low-elevation islands and sea-level rise (SLR) and accompanying high-water perturbations are predicted to escalate with climate change. To understand how SLR may impact protected islands and insular biodiversity, we modeled inundation and wave-driven flooding of a globally important seabird rookery in the subtropical Pacific. We acquired new high-resolution Digital Elevation Models (DEMs) and used the Delft3D wave model and ArcGIS to model wave heights and inundation for a range of SLR scenarios (+0.5, +1.0, +1.5, and +2.0 m) at Midway Atoll. Next, we classified vegetation to delineate habitat exposure to inundation and identified how breeding phenology, colony synchrony, and life history traits affect species-specific sensitivity. We identified 3 of 13 species as highly vulnerable to SLR in the Hawaiian Islands and quantified their atoll-wide distribution (Laysan albatross, Phoebastria immutabilis; black-footed albatross, P. nigripes; and Bonin petrel, Pterodroma hypoleuca). Our models of wave-driven flooding forecast nest losses up to 10% greater than passive inundation models at +1.0 m SLR. At projections of + 2.0 m SLR, approximately 60% of albatross and 44% of Bonin petrel nests were overwashed displacing more than 616,400 breeding albatrosses and petrels. Habitat loss due to passive SLR may decrease the carrying capacity of some islands to support seabird colonies, while sudden high-water events directly reduce survival and reproduction. This is the first study to simulate wave-driven flooding and the combined impacts of SLR, groundwater rise, and storm waves on seabird colonies. Our results highlight the need for early climate change planning and restoration of higher elevation seabird refugia to prevent low-lying protected islands from becoming ecological traps in the face of

  11. Will the Effects of Sea-Level Rise Create Ecological Traps for Pacific Island Seabirds?

    PubMed Central

    Reynolds, Michelle H.; Courtot, Karen N.; Berkowitz, Paul; Storlazzi, Curt D.; Moore, Janet; Flint, Elizabeth

    2015-01-01

    More than 18 million seabirds nest on 58 Pacific islands protected within vast U.S. Marine National Monuments (1.9 million km2). However, most of these seabird colonies are on low-elevation islands and sea-level rise (SLR) and accompanying high-water perturbations are predicted to escalate with climate change. To understand how SLR may impact protected islands and insular biodiversity, we modeled inundation and wave-driven flooding of a globally important seabird rookery in the subtropical Pacific. We acquired new high-resolution Digital Elevation Models (DEMs) and used the Delft3D wave model and ArcGIS to model wave heights and inundation for a range of SLR scenarios (+0.5, +1.0, +1.5, and +2.0 m) at Midway Atoll. Next, we classified vegetation to delineate habitat exposure to inundation and identified how breeding phenology, colony synchrony, and life history traits affect species-specific sensitivity. We identified 3 of 13 species as highly vulnerable to SLR in the Hawaiian Islands and quantified their atoll-wide distribution (Laysan albatross, Phoebastria immutabilis; black-footed albatross, P. nigripes; and Bonin petrel, Pterodroma hypoleuca). Our models of wave-driven flooding forecast nest losses up to 10% greater than passive inundation models at +1.0 m SLR. At projections of + 2.0 m SLR, approximately 60% of albatross and 44% of Bonin petrel nests were overwashed displacing more than 616,400 breeding albatrosses and petrels. Habitat loss due to passive SLR may decrease the carrying capacity of some islands to support seabird colonies, while sudden high-water events directly reduce survival and reproduction. This is the first study to simulate wave-driven flooding and the combined impacts of SLR, groundwater rise, and storm waves on seabird colonies. Our results highlight the need for early climate change planning and restoration of higher elevation seabird refugia to prevent low-lying protected islands from becoming ecological traps in the face of rising

  12. Metal levels in feathers of 12 species of seabirds from midway atoll in the northern Pacific Ocean.

    PubMed

    Burger, J; Gochfeld, M

    2000-07-20

    Seabirds are excellent subjects for examination of heavy metals because they are long-lived, feed at different distances from land, and exhibit different trophic levels. In this paper we compare the levels of lead, cadmium, mercury arsenic, chromium, manganese, selenium, and tin in the feathers of birds nesting on Midway Atoll in the northern Pacific Ocean. We test the null hypothesis that there are no interspecific differences in the levels of metals in the feathers of the adult black-footed albatross (Diomedea nigripes), Laysan albatross (Diomedea immutabilis), red-footed booby (Sula sula), great frigatebird (Fregata minor), Bonin petrel (Pterodroma hypoleuca), Christmas shearwater (Puffinus nativitatis), red-tailed tropicbird (Phaethon rubricauda), wedge-tailed shearwater (Puffinus pacificus), brown noddy (Anous stolidus), sooty tern (Stema fuscata), grey-backed tern (Stema lunata), and white tern (Gygis alba), and young of some of these species. There were interspecific differences in the levels of all metals for adults. Christmas shearwater had the highest levels of lead, cadmium, selenium and manganese, but the second lowest levels of mercury. In general, metal levels were the lowest in the smallest species (white tern), but were not the highest in the largest species (black-footed albatross), except for manganese, arsenic and mercury. There was a high variance in metal levels among adults for some species, but not for others. White tern adults were variable for lead, while Christmas shearwaters were variable for lead and cadmium. Compared to the means for metals in other birds generally (after Burger, 1993), Christmas shearwaters had higher levels of lead, white terns, brown noddy, Christmas shearwater, frigatebirds and Laysan albatrosses had higher levels of cadmium, and bonin petrel, wedge-tailed shearwater, tropicbirds, frigatebirds, red-footed boobies, and both albatrosses had higher levels of mercury. Whereas the means for lead and cadmium were below

  13. Will the Effects of Sea-Level Rise Create Ecological Traps for Pacific Island Seabirds?

    PubMed

    Reynolds, Michelle H; Courtot, Karen N; Berkowitz, Paul; Storlazzi, Curt D; Moore, Janet; Flint, Elizabeth

    2015-01-01

    More than 18 million seabirds nest on 58 Pacific islands protected within vast U.S. Marine National Monuments (1.9 million km2). However, most of these seabird colonies are on low-elevation islands and sea-level rise (SLR) and accompanying high-water perturbations are predicted to escalate with climate change. To understand how SLR may impact protected islands and insular biodiversity, we modeled inundation and wave-driven flooding of a globally important seabird rookery in the subtropical Pacific. We acquired new high-resolution Digital Elevation Models (DEMs) and used the Delft3D wave model and ArcGIS to model wave heights and inundation for a range of SLR scenarios (+0.5, +1.0, +1.5, and +2.0 m) at Midway Atoll. Next, we classified vegetation to delineate habitat exposure to inundation and identified how breeding phenology, colony synchrony, and life history traits affect species-specific sensitivity. We identified 3 of 13 species as highly vulnerable to SLR in the Hawaiian Islands and quantified their atoll-wide distribution (Laysan albatross, Phoebastria immutabilis; black-footed albatross, P. nigripes; and Bonin petrel, Pterodroma hypoleuca). Our models of wave-driven flooding forecast nest losses up to 10% greater than passive inundation models at +1.0 m SLR. At projections of + 2.0 m SLR, approximately 60% of albatross and 44% of Bonin petrel nests were overwashed displacing more than 616,400 breeding albatrosses and petrels. Habitat loss due to passive SLR may decrease the carrying capacity of some islands to support seabird colonies, while sudden high-water events directly reduce survival and reproduction. This is the first study to simulate wave-driven flooding and the combined impacts of SLR, groundwater rise, and storm waves on seabird colonies. Our results highlight the need for early climate change planning and restoration of higher elevation seabird refugia to prevent low-lying protected islands from becoming ecological traps in the face of rising

  14. Metal levels in feathers of 12 species of seabirds from midway atoll in the northern Pacific Ocean.

    PubMed

    Burger, J; Gochfeld, M

    2000-07-20

    Seabirds are excellent subjects for examination of heavy metals because they are long-lived, feed at different distances from land, and exhibit different trophic levels. In this paper we compare the levels of lead, cadmium, mercury arsenic, chromium, manganese, selenium, and tin in the feathers of birds nesting on Midway Atoll in the northern Pacific Ocean. We test the null hypothesis that there are no interspecific differences in the levels of metals in the feathers of the adult black-footed albatross (Diomedea nigripes), Laysan albatross (Diomedea immutabilis), red-footed booby (Sula sula), great frigatebird (Fregata minor), Bonin petrel (Pterodroma hypoleuca), Christmas shearwater (Puffinus nativitatis), red-tailed tropicbird (Phaethon rubricauda), wedge-tailed shearwater (Puffinus pacificus), brown noddy (Anous stolidus), sooty tern (Stema fuscata), grey-backed tern (Stema lunata), and white tern (Gygis alba), and young of some of these species. There were interspecific differences in the levels of all metals for adults. Christmas shearwater had the highest levels of lead, cadmium, selenium and manganese, but the second lowest levels of mercury. In general, metal levels were the lowest in the smallest species (white tern), but were not the highest in the largest species (black-footed albatross), except for manganese, arsenic and mercury. There was a high variance in metal levels among adults for some species, but not for others. White tern adults were variable for lead, while Christmas shearwaters were variable for lead and cadmium. Compared to the means for metals in other birds generally (after Burger, 1993), Christmas shearwaters had higher levels of lead, white terns, brown noddy, Christmas shearwater, frigatebirds and Laysan albatrosses had higher levels of cadmium, and bonin petrel, wedge-tailed shearwater, tropicbirds, frigatebirds, red-footed boobies, and both albatrosses had higher levels of mercury. Whereas the means for lead and cadmium were below

  15. Human disturbance alters endocrine and immune responses in the Galapagos marine iguana (Amblyrhynchus cristatus).

    PubMed

    French, Susannah S; DeNardo, Dale F; Greives, Timothy J; Strand, Christine R; Demas, Gregory E

    2010-11-01

    Anthropogenic disturbance is a relevant and widespread facilitator of environmental change and there is clear evidence that it impacts natural populations. While population-level responses to major anthropogenic changes have been well studied, individual physiological responses to mild disturbance can be equally critical to the long-term survival of a species, yet they remain largely unexamined. The current study investigated the impact of seemingly low-level anthropogenic disturbance (ecotourism) on stress responsiveness and specific fitness-related immune measures in different breeding stages of the marine iguana (Amblyrhynchus cristatus). Specifically, we found stress-induced elevations in plasma corticosterone among tourist-exposed populations relative to undisturbed populations. We also found changes in multiple immunological responses associated with stress-related effects of human disturbance, including bacterial killing ability, cutaneous wound healing, and hemolytic complement activity, and the responses varied according to reproductive state. By identifying health-related consequences of human disturbance, this study provides critical insight into the conservation of a well-known species that has a very distinct ecology. The study also broadens the foundation of knowledge needed to understand the global significance of various levels of human disturbance. PMID:20708010

  16. Environmental Education in the Galapagos: Where Do We Go From Here?

    ERIC Educational Resources Information Center

    Stepath, Carl M.

    2009-01-01

    Our future leaders' environmental understanding improves their resource management skills and decision-making capacity. Community awareness and "hands-on" involvement preserves bio-diversity and addresses human impacts. This report discusses the importance of environmental education, and effective learning programs. Quality education in the school…

  17. Carriage of antibiotic-resistant enteric bacteria varies among sites in Galapagos reptiles.

    PubMed

    Wheeler, Emily; Hong, Pei-Ying; Bedon, Lenin Cruz; Mackie, Roderick I

    2012-01-01

    Increased overlap between humans and wildlife populations has increased the risk for novel disease emergence. Detecting contacts with a high risk for transmission of pathogens requires the identification of dependable measures of microbial exchange. We evaluated antibiotic resistance as a molecular marker for the intensity of human-wildlife microbial connectivity in the Galápagos Islands. We isolated Escherichia coli and Salmonella enterica from the feces of land iguanas (Conolophus sp.), marine iguanas (Amblyrhynchus cristatus), giant tortoises (Geochelone nigra), and seawater, and tested these bacteria with the use of the disk diffusion method for resistance to 10 antibiotics. Antibiotic-resistant bacteria were found in reptile feces from two tourism sites (Isla Plaza Sur and La Galapaguera on Isla San Cristóbal) and from seawater close to a public use beach near Puerto Baquerizo Moreno on Isla San Cristóbal. No resistance was detected at two protected beaches on more isolated islands (El Miedo on Isla Santa Fe and Cape Douglas on Isla Fernandina) and at a coastal tourism site (La Lobería on Isla San Cristóbal). Eighteen E. coli isolates from three locations, all sites relatively proximate to a port town, were resistant to ampicillin, doxycycline, tetracycline, and trimethoprin/sulfamethoxazole. In contrast, only five S. enterica isolates showed a mild decrease in susceptibility to doxycycline and tetracycline from these same sites (i.e., an intermediate resistance phenotype), but no clinical resistance was detected in this bacterial species. These findings suggest that reptiles living in closer proximity to humans potentially have higher exposure to bacteria of human origin; however, it is not clear from this study to what extent this potential exposure translates to ongoing exchange of bacterial strains or genetic traits. Resistance patterns and bacterial exchange in this system warrant further investigation to understand better how human associations influence disease risk in endemic Galápagos wildlife.

  18. Designing Tools for Ocean Exploration. Galapagos Rifts Expedition--Grades 9-12. Overview: Ocean Exploration.

    ERIC Educational Resources Information Center

    National Oceanic and Atmospheric Administration (DOC), Rockville, MD.

    This activity teaches about the complexity of ocean exploration, the technological applications and capabilities required for ocean exploration, the importance of teamwork in scientific research projects, and developing abilities necessary to do scientific inquiry. The activity provides learning objectives, a list of needed materials, key…

  19. Come On Down! Galapagos Rift Expedition--Grades 7-8. Overview: Ocean Exploration.

    ERIC Educational Resources Information Center

    National Oceanic and Atmospheric Administration (DOC), Rockville, MD.

    These activities are designed to teach about ocean exploration. Students are expected to research the development and implementation of a research vessel/vehicle used for deep ocean exploration, calculate the density of objects by determining the mass and volume, and construct a device that exhibits neutral buoyancy. The activity provides learning…

  20. Lineage sorting in multihost parasites: Eidmanniella albescens and Fregatiella aurifasciata on seabirds from the Galapagos Islands

    PubMed Central

    Rivera-Parra, Jose L; Levin, Iris I; Johnson, Kevin P; Parker, Patricia G

    2015-01-01

    Parasites comprise a significant percentage of the biodiversity of the planet and are useful systems to test evolutionary and ecological hypotheses. In this study, we analyze the effect of host species identity and the immediate local species assemblage within mixed species colonies of nesting seabirds on patterns of genetic clustering within two species of multihost ectoparasitic lice. We use three genetic markers (one mitochondrial, COI, and two nuclear, EF1-α and wingless) and maximum likelihood phylogenetic trees to test whether (1) parasites show lineage sorting based on their host species; and (2) switching of lineages to the alternate host species depends on the immediate local species assemblage of individual hosts within a colony. Specifically, we examine the genetic structure of two louse species: Eidmanniella albescens, infecting both Nazca (Sula granti) and blue-footed boobies (Sula nebouxii), and Fregatiella aurifasciata, infecting both great (Fregata minor) and magnificent frigatebirds (Fregata magnificens). We found that host species identity was the only factor explaining the patterns of genetic structure in both parasites. In both cases, there is evident genetic differentiation depending on the host species. Thus, a revision of the taxonomy of these louse species is needed. One possible explanation of this pattern is extremely low louse migration rates between host species, perhaps influenced by fine-scale spatial separation of host species within mixed colonies, and low parasite infrapopulation numbers. PMID:26380662

  1. Pyroxenes and olivines from a Galapagos spreading center (GSC) rhyodacite record crystal fractionation and magma mixing

    SciTech Connect

    Mattson, S.R.; Byerly, G.R.; Carpenter, P.

    1985-01-01

    Phenocrysts and xenocrysts of augite, subcalcic augite, pigeonite, orthopyroxene, and olivine in two glassy rhyodacite dredge samples from 95/sup 0/W on the GSC reflect a complex history of fractional crystallization and magma mixing. The pyroxene compositions can be grouped into clusters reflecting three major sources: a) Fenumber approx. 0.2 from basalt, b) Fenumber approx. 0.5 from rhyodacite, and c) Fenumber approx. 0.6 from rhyolite. Pyroxene Ti/Al ratios of 1:14, 1:7 and 1:3 have Fenumbers suggesting original crystallization from basalt, rhyodacite, and rhyolite melts respectively. These general compositional groups are typical of those produced during fractional crystallization of basalt to rhyolite. At relatively constant Fenumber the augites in any group display a wide spectrum of variation in Wo, Al, and Ti. Basaltic augite core to rim variations exhibit both increases and decreases in Ti at nearly constant Fenumber. A continuous variation in subcalcic augites is present from Fe-augite to Fe-pigeonite. These effects are likely kinetic, perhaps due to rapid cooling rates, but possibly due to supersaturation produced during mixing. Magma mixing may have played an important role in bringing together these contrasting components. The abundance of very-fine-grained basaltic xenoliths and xenocrysts, the glassy rhyolitic inclusions and associated xenocrysts, along with major reverse zoning in Fenumber or major discontinuities in Fenumber in the ferromagnesian phases all point to coexisting melts of radically differing composition.

  2. The Galapagos archipelago: A natural laboratory to examine sharp hydroclimatic, geologic and anthropogenic gradients

    USGS Publications Warehouse

    Percy, Madelyn; Schmitt, Sarah; Riveros-Iregui, Diego; Mirus, Benjamin B.

    2016-01-01

    Poor understanding of the water cycle in tropical ecosystems has the potential to exacerbate water shortages and water crises in the region. We suggest that the Galápagos Islands provide an excellent proxy to regions across the tropics as a result of sharp hydroclimatic, anthropogenic, and pedohydrologic gradients across the archipelago. Hydroclimatic and pedohydrologic gradients are found across different elevations on single islands, as well as across the archipelago, whereas anthropogenic gradients reflect land use and land cover change across islands as population and growth in tourism have affected individual islands differently. This article highlights specific opportunities to further examine our understanding of the interactions between water and critical zone processes in tropical ecosystems, making connections between the Galápagos archipelago and much of the understudied tropics. The Galápagos archipelago offers a natural laboratory through which we can examine current threats to freshwater security as well as the dynamics of coupled natural and human systems.

  3. Relationships, origin, and diversity of Galapagos tomatoes: implications for the conservation of natural populations.

    PubMed

    Nuez, Fernando; Prohens, Jaume; Blanca, José M

    2004-01-01

    Endemic Galápagos tomatoes (Lycopersicon cheesmanii) are of great value for cultivated tomato (L. esculentum) breeding, and therefore their conservation is of significance. Although within L. cheesmanii there is heterogeneity for many traits and formal infraspecific classification is not justified, here we distinguish three forms, without taxonomic significance, of L. cheesmanii that are of interest to breeders because of their distinctive morphology and habitat preferences: L. cheesmanii 'short' (one- to two-pinnate leaves, short internodes, and coastal habitats), L. cheesmanii 'long' (one- to two-pinnate leaves, long internodes, and inland habitats), and L. cheesmanii forma minor (three- to four-pinnate leaves, short internodes, and coastal habitats). In a recent survey of tomato populations in the Galápagos Islands, we found that several populations of L. cheesmanii reported 30-50 years earlier had disappeared, mostly as a consequence of human activity. In addition, a previously unreported invasive wild red-fruited form, which we named L. esculentum 'Gal cer,' was found on the island of Santa Cruz. The total diversity (estimated with amplified fragment length polymorphisms [AFLPs]) within L. cheesmanii (H(T) = 0.051) is almost as high as that for the mainland wild species L. pimpinellifolium (H(T) = 0.072). Lycopersicon esculentum 'Gal cer,' on the other hand, has a much lower diversity (H(T) = 0.014). Comparison of AFLP fragments shared by L. esculentum 'Gal cer' with other species showed that it is closely related to weedy tomato L. esculentum var. cerasiforme and, therefore, likely of recent origin. Genetic differentiation among the three native L. cheesmanii forms is low (G(ST) = 0.235), indicating that they share a common genetic background. Nonetheless, L. cheesmanii 'short' is about twice as diverse as L. cheesmanii 'long' or L. cheesmanii f. minor. UPGMA cluster and principal components analysis distinguish four groups within Eulycopersicon: L. pimpinellifolium, cultivated L. esculentum, L. esculentum var. cerasiforme including L. esculentum 'Gal cer,' and L. cheesmanii. The geographic distance and genetic distance in the wild forms of Galápagos tomatoes were not correlated. Apart from the pressure of humans, some native L. cheesmanii populations, especially L. cheesmanii 'long,' might be displaced by invasive L. esculentum 'Gal cer' because they share a similar habitat. We did not find evidence of intercrossing of L. cheesmanii with introduced L. esculentum, but occasional hybridization that contributes to loss of genetic integrity of L. cheesmanii cannot be ruled out. Establishment of reserves of L. cheesmanii to protect this species from introduced herbivorous animals and from hybridization with L. esculentum 'Gal cer' would help to conserve L. cheesmanii. Furthermore, accessions collected by C. M. Rick and others in the 1950s-1970s and now stored in germplasm banks could be used to reinstate some extinct populations.

  4. Invaders of pollination networks in the Galapagos Islands: emergence of novel communities.

    PubMed

    Traveset, Anna; Heleno, Ruben; Chamorro, Susana; Vargas, Pablo; McMullen, Conley K; Castro-Urgal, Rocío; Nogales, Manuel; Herrera, Henri W; Olesen, Jens M

    2013-05-01

    The unique biodiversity of most oceanic archipelagos is currently threatened by the introduction of alien species that can displace native biota, disrupt native ecological interactions, and profoundly affect community structure and stability. We investigated the threat of aliens on pollination networks in the species-rich lowlands of five Galápagos Islands. Twenty per cent of all species (60 plants and 220 pollinators) in the pooled network were aliens, being involved in 38 per cent of the interactions. Most aliens were insects, especially dipterans (36%), hymenopterans (30%) and lepidopterans (14%). These alien insects had more links than either endemic pollinators or non-endemic natives, some even acting as island hubs. Aliens linked mostly to generalized species, increasing nestedness and thus network stability. Moreover, they infiltrated all seven connected modules (determined by geographical and phylogenetic constraints) of the overall network, representing around 30 per cent of species in two of them. An astonishingly high proportion (38%) of connectors, which enhance network cohesiveness, was also alien. Results indicate that the structure of these emergent novel communities might become more resistant to certain type of disturbances (e.g. species loss), while being more vulnerable to others (e.g. spread of a disease). Such notable changes in network structure as invasions progress are expected to have important consequences for native biodiversity maintenance.

  5. Differentiation with drift: a spatio-temporal genetic analysis of Galapagos mockingbird populations (Mimus spp.).

    PubMed

    Hoeck, Paquita E A; Bollmer, Jennifer L; Parker, Patricia G; Keller, Lukas F

    2010-04-12

    Small and isolated island populations provide ideal systems to study the effects of limited population size, genetic drift and gene flow on genetic diversity. We assessed genetic diversity within and differentiation among 19 mockingbird populations on 15 Galápagos islands, covering all four endemic species, using 16 microsatellite loci. We tested for signs of drift and gene flow, and used historic specimens to assess genetic change over the last century and to estimate effective population sizes. Within-population genetic diversity and effective population sizes varied substantially among island populations and correlated strongly with island size, suggesting that island size serves as a good predictor for effective population size. Genetic differentiation among populations was pronounced and increased with geographical distance. A century of genetic drift did not change genetic diversity on an archipelago-wide scale, but genetic drift led to loss of genetic diversity in small populations, especially in one of the two remaining populations of the endangered Floreana mockingbird. Unlike in other Galápagos bird species such as the Darwin's finches, gene flow among mockingbird populations was low. The clear pattern of genetically distinct populations reflects the effects of genetic drift and suggests that Galápagos mockingbirds are evolving in relative isolation.

  6. Galapagos hydrothermal mounds: stratigraphy and chemistry revealed by deep-sea drilling.

    PubMed

    Natland, J H; Rosendahl, B; Hekinian, R; Dmitriev, Y; Fodor, R V; Goll, R M; Hoffert, M; Humphris, S E; Mattey, D P; Petersen, N; Roggenthen, W; Schrader, E L; Srivastava, R K; Warren, N

    1979-05-11

    The Galápagos mounds sea-floor hydrothermal system is at least 300,000 years old and once produced manganese-poor sediments, which nearly blanketed the area of the present mounds field. Present-day mound deposits are limited manganese-rich exposures, suggesting that the system has changed from rock-to water-dominated and has diminished in intensity with time.

  7. Galapagos on the Potomac--Or the Evolution of Federal Policy.

    ERIC Educational Resources Information Center

    Mann, Dale

    1984-01-01

    The research on effective schools provides an opportunity for federally supported school improvement. A new challenge to policymakers will be presented by the satellite delivery of a totally engineered learning environment to subscribing homes. (MLF)

  8. Temporal and spatial variation in mercury concentrations in some albatrosses and petrels from the sub-Antarctic

    SciTech Connect

    Thompson, D.R.; Furness, R.W.; Lewis, S.A. )

    1993-01-01

    Mercury concentrations in albatrosses and some other large procellariiforms are very much higher than found in other groups of seabirds. Analysis of mercury concentrations in feather samples collected prior to 1950 and after this date showed slight, but significant, increased in three out of ten sub-Antarctic procellariiform species. The lack of widespread and pronounced increases in mercury concentrations in procellariiforms between these periods may indicate that industrial and agricultural emissions of mercury in the southern hemisphere have been relatively minor and the high concentrations are predominantly due to natural processes. Mercury concentrations were relatively consistent between body feathers of individuals, and showed no variation related to adult age (in years). Within species, mercury concentrations tended to be highest in New Zealand populations and lowest in Falkland Island and South Georgia populations. Mercury concentrations also varied among species, but not in a way that could be related to diet. 27 refs., 1 fig., 3 tabs.

  9. Pelagic seabird surveys in the Tuamotu and Gambier Archipelagos, French Polynesia

    USGS Publications Warehouse

    Vanderwerf, E.A.; Pierce, R.J.; Gill, V.A.; Wragg, G.; Raust, P.; Tibbitts, T.L.

    2006-01-01

    We conducted pelagic seabird surveys in the Gambier and Tuamotu Archipelagos in the southeastern Pacific Ocean totaling 40 hours during 7-27 March 2003 and 22.5 hours during 22-27 July 2001. We used a 300-m-wide strip transect to estimate seabird density, and we estimated relative abundance of birds at all distances. In 2001, we observed a total of 326 birds of 18 species. The mean relative abundance of all birds was 14.3 ?? 3.1/h. Red-footed Booby Sula sula was the most abundant species (5.6/h), followed by White Tern Gygis alba (3.4/h), and Great Crested or Swift Tern Sterna bergii (1.2/h). In 2003, we observed a total of 1463 birds of 25 species. The mean relative abundance of all birds was 36.6 ?? 11.4/h and the mean density of all birds was 4.14 ?? 0.72/km2. Brown Noddy Anous stolidus was the most abundant species (17.6/h, 1.5/km2), followed by White Tern (8.4/h, 1.3/km2), and Red-footed Booby (4.6/h, 0.8/km2). Several globally or locally rare species were observed infrequently, including Phoenix Petrel Pterodroma alba (0.1/h, 0.03/km2). Distribution of birds was uneven, with long periods of no birds punctuated by occasional feeding flocks. In 2003, species diversity was related to length of observation period, with more species observed on longer segments (r2 = 0.58, F1.5 = 6.03, P = 0.05). Although the duration and extent of our surveys were limited, these data are valuable because little published information is available on pelagic seabirds in southeastern Polynesia.

  10. Foraging segregation and genetic divergence between geographically proximate colonies of a highly mobile seabird

    USGS Publications Warehouse

    Wiley, Anne E.; Welch, Andreanna J.; Ostrom, P.H.; James, Helen F.; Stricker, C.A.; Fleischer, R.C.; Gandhi, H.; Adams, J.; Ainley, D.G.; Duvall, F.; Holmes, N.; Hu, D.; Judge, S.; Penniman, J.; Swindle, K.A.

    2012-01-01

    Foraging segregation may play an important role in the maintenance of animal diversity, and is a proposed mechanism for promoting genetic divergence within seabird species. However, little information exists regarding its presence among seabird populations. We investigated genetic and foraging divergence between two colonies of endangered Hawaiian petrels (Pterodroma sandwichensis) nesting on the islands of Hawaii and Kauai using the mitochondrial Cytochrome b gene and carbon, nitrogen and hydrogen isotope values (?? 13C, ?? 15N and ??D, respectively) of feathers. Genetic analyses revealed strong differentiation between colonies on Hawaii and Kauai, with ?? ST = 0. 50 (p < 0. 0001). Coalescent-based analyses gave estimates of <1 migration event per 1,000 generations. Hatch-year birds from Kauai had significantly lower ?? 13C and ?? 15N values than those from Hawaii. This is consistent with Kauai birds provisioning chicks with prey derived from near or north of the Hawaiian Islands, and Hawaii birds provisioning young with prey from regions of the equatorial Pacific characterized by elevated ?? 15N values at the food web base. ?? 15N values of Kauai and Hawaii adults differed significantly, indicating additional foraging segregation during molt. Feather ??D varied from -69 to 53???. This variation cannot be related solely to an isotopically homogeneous ocean water source or evaporative water loss. Instead, we propose the involvement of salt gland excretion. Our data demonstrate the presence of foraging segregation between proximately nesting seabird populations, despite high species mobility. This ecological diversity may facilitate population coexistence, and its preservation should be a focus of conservation strategies. ?? 2011 Springer-Verlag (outside the USA).

  11. Foraging segregation and genetic divergence between geographically proximate colonies of a highly mobile seabird.

    PubMed

    Wiley, Anne E; Welch, Andreanna J; Ostrom, Peggy H; James, Helen F; Stricker, Craig A; Fleischer, Robert C; Gandhi, Hasand; Adams, Josh; Ainley, David G; Duvall, Fern; Holmes, Nick; Hu, Darcy; Judge, Seth; Penniman, Jay; Swindle, Keith A

    2012-01-01

    Foraging segregation may play an important role in the maintenance of animal diversity, and is a proposed mechanism for promoting genetic divergence within seabird species. However, little information exists regarding its presence among seabird populations. We investigated genetic and foraging divergence between two colonies of endangered Hawaiian petrels (Pterodroma sandwichensis) nesting on the islands of Hawaii and Kauai using the mitochondrial Cytochrome b gene and carbon, nitrogen and hydrogen isotope values (δ(13)C, δ(15)N and δD, respectively) of feathers. Genetic analyses revealed strong differentiation between colonies on Hawaii and Kauai, with Φ(ST) = 0.50 (p < 0.0001). Coalescent-based analyses gave estimates of <1 migration event per 1,000 generations. Hatch-year birds from Kauai had significantly lower δ(13)C and δ(15)N values than those from Hawaii. This is consistent with Kauai birds provisioning chicks with prey derived from near or north of the Hawaiian Islands, and Hawaii birds provisioning young with prey from regions of the equatorial Pacific characterized by elevated δ(15)N values at the food web base. δ(15)N values of Kauai and Hawaii adults differed significantly, indicating additional foraging segregation during molt. Feather δD varied from -69 to 53‰. This variation cannot be related solely to an isotopically homogeneous ocean water source or evaporative water loss. Instead, we propose the involvement of salt gland excretion. Our data demonstrate the presence of foraging segregation between proximately nesting seabird populations, despite high species mobility. This ecological diversity may facilitate population coexistence, and its preservation should be a focus of conservation strategies.

  12. Pore water chemistry of the Mounds Hydrothermal Field, Galapagos Spreading Center: Results from Glomar Challenger Piston Coring

    NASA Astrophysics Data System (ADS)

    Bender, Michael L.

    1983-01-01

    On DSDP Leg 70, Glomar Challenger piston cored hydrothermal MnO2-encrusted nontronite mounds and adjacent pelagic sediments through to basement. Pore waters were collected by centrifuging, squeezing, and in situ sampling; analyses are presented here for Ca, Mg, Si, NH3, Mn, and Fe. Our results confirm Maris and Bender's (1982) conclusions that hydrothermal solutions enriched in Ca by 1-2 mM and depleted in Mg by ˜2 mM are upwelling through the mounds and the surrounding pelagic sediments. Si, NH3, and Mn2+ concentrations generally increase upcore, reflecting addition of products of metabolic reactions to upwelling hydrothermal solutions. Pore water iron concentrations decrease upcore, probably as a result of oxidation and precipitation of upwelling hydrothermal iron. The formation of nontronite (Fe(III)4Si8O20(OH)4) involves oxidation of dissolved Fe2+. Several models, constrained by the electron balance, are proposed to explain the process of nontronite formation. The stratigraphy of the mounds (thick nontronite covered by a thin MnO2 crust) may be explained by postulating Fe2+ oxidation by MnO2 and replacement of MnO2 by nontronite at the base of the MnO2 crust, followed by upward migration of Mn2+ and precipitation of MnO2 at the sediment water interface.

  13. Deformation and stress-change modeling at Sierra Negra volcano, Galapagos, from ENVISAT INSAR and GPS observations

    USGS Publications Warehouse

    Jonsson, Sigurjon; Chadwick, W.W.; Poland, M.; Geist, D.

    2008-01-01

    We use radar interferograms and GPS observations to constrain models of magma accumulation and faulting at Sierra Negra volcano, Galápagos, during the years before its 2005 eruption. The data have shown ~5 m of pre-eruption uplift and multiple trapdoor faulting events on an intra-caldera fault system. We find the pattern of uplift to be consistent with an inflating sill at 2.2 km depth under the caldera. Our deformation modeling and stress-change calculations suggest that the inflating sill triggered faulting on an inward- dipping thrust fault and that the faulting in turn relieved the pressure within the sill. This sill-fault interaction tends to thicken the sill and limit its lateral extent within the area bounded by the fault.

  14. A Change From Inflation to Deflation at Sierra Negra Volcano, Galapagos Revealed by GPS and Gravity Monitoring

    NASA Astrophysics Data System (ADS)

    Johnson, D.; Geist, D.; Chadwick, B.

    2002-12-01

    A network of GPS and gravity stations was installed in January 2000 at Sierra Negra volcano and has been occupied twice more at annual intervals. Displacements during the initial year (1/00-1/01) were inflationary, consistent with previous INSAR results but notably smaller in magnitude. We observed a maximum uplift of 7 cm/yr compared to rates of 30-83 cm/yr observed by INSAR between 1992 and 1999. The most recent survey revealed a well-defined subsidence centered within the caldera, between 1/01 and 5/02. The observed vertical displacements are up to -11.5 cm/yr and 4.1 cm/yr horizontally. A point source solution gives a source depth of 2.6 km and a volumetric subsidence rate of -5 million cubic meters/yr. As is generally the case, a sill model also yields solutions with reasonable model fits. With 20 sites distributed over the displacement field, we have good control on the ratios of horizontal to vertical change, which is necessary to differentiate between a point or spherical source and a sill source. In order to better establish temporal trends, six continuous GPS sites (two dual frequency and four single frequency instruments) were installed with UNAVCO support in May 2002. These telemeter data from which daily solutions are computed. 90 days of results from this continuous network show sustained deflation at a rate of about 10 cm/yr. Modeling of these results indicates a relatively shallow-seated source near 3 km depth and a volumetric subsidence rate of -7 million cubic meters per year, similar to the 2001-2002 campaign GPS observations. We do not know exactly when the change from inflation to deflation occurred, only that it was sometime between January 2000 and May 2002. Gravity observations were made annually at a subset of the GPS benchmarks on a radial profile over the Sierra Negra deformation source. Complete analysis of the gravity data awaits finalization of the calibration parameters for the three gravimeters used. The gravity results will discern whether the subsidence was accompanied by mass loss from the subsurface reservoir, or if the subsidence was due to in-situ volumetric contraction of material without a removal of mass.

  15. Ongoing Active Deformation Processes at Fernandina Volcano (Galapagos) Detected via Multi-Orbit COSMO-SkyMed SAR Data Analysis

    NASA Astrophysics Data System (ADS)

    Pepe, Susi; Castaldo, Raffaele; De Luca, Claudio; Casu, Francesco; Tizzani, Pietro; Sansosti, Eugenio

    2014-05-01

    Fernandina Volcano, Galápagos (Ecuador), has experienced several uplift and eruption episodes over the last twenty-two years. The ground deformation between 2002 and 2006 was interpreted as the effect of an inflation phenomenon of two separate magma reservoirs beneath the caldera. Moreover, the uplift deformation occurred during the 2005 eruption was concentrated near the circumferential eruptive fissures, while being superimposed on a broad subsidence centred on the caldera. The geodetic studies emphasized the presence of two sub volcanic lateral intrusions from the central storage system in December 2006 and August 2007. The latest eruption in 2009 was characterized by lava flows emitted from the SW radial fissures. We analyze the spatial and temporal ground deformation between March 2012 and July 2013, by using data acquired by COSMO-SkyMed X-band constellation along both ascending and descending orbits and by applying advanced InSAR techniques. In particular, we use the SBAS InSAR approach and combine ascending and descending time series to produce vertical and East-West components of the mean deformation velocity and deformation time series. Our analysis revealed a new uplift phenomenon due to the stress concentration inside the shallow magmatic system of the volcano. In particular, the vertical mean velocity map shows that the deformation pattern is concentrated inside caldera region and is characterized by strongly radial symmetry with a maximum displacement of about 20 cm in uplift; an axial symmetry is also observed in the EW horizontal mean velocity map, showing a maximum displacement of about +12 cm towards East for the SE flank, and -12 cm towards West for the NW flank of the volcano. Moreover, the deformation time series show a rather linear uplift trend from March to September 2012, interrupted by a low deformation rate interval lasting until January 2013. After this stage, the deformation shows again a linear behaviour with an increased uplift rate. Starting from these observations, we set up a 3D time dependent numerical model in a fluid dynamic context; in particular, we consider the creeping flow approximation in order to simulate the stress temporal evolution inside the volcano conduit. The preliminary results show that the stress is concentred in the areas corresponding to the circumferential eruptive fissures mentioned above. The COSMO-SkyMed data used in this study have been processed at IREA-CNR within the SAR4Volcanoes project under Italian Space Agency agreement n. I/034/11/0.

  16. Mapping and assessing variability in the Antarctic marginal ice zone, pack ice and coastal polynyas in two sea ice algorithms with implications on breeding success of snow petrels

    NASA Astrophysics Data System (ADS)

    Stroeve, Julienne C.; Jenouvrier, Stephanie; Campbell, G. Garrett; Barbraud, Christophe; Delord, Karine

    2016-08-01

    Sea ice variability within the marginal ice zone (MIZ) and polynyas plays an important role for phytoplankton productivity and krill abundance. Therefore, mapping their spatial extent as well as seasonal and interannual variability is essential for understanding how current and future changes in these biologically active regions may impact the Antarctic marine ecosystem. Knowledge of the distribution of MIZ, consolidated pack ice and coastal polynyas in the total Antarctic sea ice cover may also help to shed light on the factors contributing towards recent expansion of the Antarctic ice cover in some regions and contraction in others. The long-term passive microwave satellite data record provides the longest and most consistent record for assessing the proportion of the sea ice cover that is covered by each of these ice categories. However, estimates of the amount of MIZ, consolidated pack ice and polynyas depend strongly on which sea ice algorithm is used. This study uses two popular passive microwave sea ice algorithms, the NASA Team and Bootstrap, and applies the same thresholds to the sea ice concentrations to evaluate the distribution and variability in the MIZ, the consolidated pack ice and coastal polynyas. Results reveal that the seasonal cycle in the MIZ and pack ice is generally similar between both algorithms, yet the NASA Team algorithm has on average twice the MIZ and half the consolidated pack ice area as the Bootstrap algorithm. Trends also differ, with the Bootstrap algorithm suggesting statistically significant trends towards increased pack ice area and no statistically significant trends in the MIZ. The NASA Team algorithm on the other hand indicates statistically significant positive trends in the MIZ during spring. Potential coastal polynya area and amount of broken ice within the consolidated ice pack are also larger in the NASA Team algorithm. The timing of maximum polynya area may differ by as much as 5 months between algorithms. These differences lead to different relationships between sea ice characteristics and biological processes, as illustrated here with the breeding success of an Antarctic seabird.

  17. Caldera Collapse in the Galapagos Islands, 1968: The largest known collapse since 1912 followed a flank eruption and explosive volcanism within the caldera.

    PubMed

    Simkin, T; Howard, K A

    1970-07-31

    The summit caldera of Isla Fernandina, a large, uninhabited basaltic shield volcano, was further enlarged by 1 to 2 km(3) in June 1968. A small quake and large vapor cloud on 11 June were followed 4 hours later by a remarkable volcanic ash cloud and, after another hour, by a major explosion recorded at infrasonic stations throughout the hemisphere. Seismic activity increased to a peak on 19 June, when more than 200 events per day were recorded by a seismograph 140 km away. Several hundred quakes were in the magnitude range 4.0 to 5.4 m(b), but few such events were recorded after 23 June. Unusual lightning accompanied the major cloud, and, during the evening of 11 June, distant observers reported red glow and flashes from the area. Fine ash fell that night and much of the next day to distances at least 350 km from the volcano. PMID:17739001

  18. Causes of mortality of wild birds submitted to the Charles Darwin Research Station, Santa Cruz, Galapagos, Ecuador from 2002-2004.

    PubMed

    Gottdenker, Nicole L; Walsh, Timothy; Jiménez-Uzcátegui, Gustavo; Betancourt, Franklin; Cruz, Marilyn; Soos, Catherine; Miller, R Eric; Parker, Patricia G

    2008-10-01

    Necropsy findings were reviewed from wild birds submitted to the Charles Darwin Research Station, Santa Cruz Island, Galápagos Archipelago between 2004 and 2006. One hundred and ninety cases from 27 different species were submitted, and 178 of these cases were evaluated grossly or histologically. Trauma and trauma-related deaths (n=141) dominated necropsy submissions. Infectious causes of avian mortality included myiasis due to Philornis sp. (n=6), avian pox (n=1), and schistosomosis (n=1).

  19. Predation as a cost of sexual communication in nocturnal seabirds: an experimental approach using acoustic signals.

    PubMed

    Mougeot; Bretagnolle

    2000-11-01

    Conspicuous behaviour, such as sexual advertisement, exposes animals to predation; mate attraction thus often conflicts with antipredator behaviour. We investigated whether an avian predator, the brown skua, Catharacta antarctica lönnbergi, uses the mate attraction calls of colonial seabirds, the petrels. The majority of petrels attract mates at night and vocalizations are their main way of communicating. At our study sites, skua predation on nocturnal petrels was heavy, and concentrated particularly on a single species, the blue petrel, Halobaena caerulea. Using playback experiments, we showed that skuas can use male petrel calls as a cue for prey location and selection. This listening behaviour of skuas probably imposes a major constraint on advertising petrels, and especially on single males which face a trade-off between attracting females (which respond by calling in flight) and avoiding predation. We also investigated the consequences of this predation risk on the behaviour of petrels: a second set of playback experiments showed that the most heavily preyed on petrel species could use skua territorial calls to infer predation risk and stop calling thereafter, which may reduce conspicuousness and predation risk. Copyright 2000 The Association for the Study of Animal Behaviour. PMID:11082235

  20. Ecology and Evolution: Islands of Change.

    ERIC Educational Resources Information Center

    Benz, Richard

    This book was designed for middle and junior high school science classes and focuses on island biogeography, ecology, and evolution. Sections include: (1) "Galapagos: Frame of Reference"; (2) "Ecology and Islands"; and (3) "Evolution." Nineteen standards-based activities use the Galapagos Islands as a running theme but are designed to help…

  1. The relationships of seabird assemblages to physical habitat features in Pacific equatorial waters during spring 1984-1991

    USGS Publications Warehouse

    Ribic, C.A.; Ainley, D.G.

    1997-01-01

    The association of seabird species groups with physical habitat was investigated in the eastern tropical Pacific Ocean, far from any breeding colonies. This avoided birds that commute between colony and feeding habitat, behaviour that confuses associations with specific water types and current systems. Seabirds were counted on duplicate tracks in the eastern tropical Pacific each spring from 1984-1991. On each cruise, seabird habitat was measured on the basis of six factors and focused on three species groups: (A) black-winged petrel and white-winged petrel, (B) Juan Fernandez petrel, wedge-tailed shearwater, and sooty tern, and (C) Leach's storm-petrel and wedge-rumped storm-petrel. Group A was associated with the South Equatorial Current, particularly in cooler waters (median of 26.4??C); both petrel species followed this assemblage association with current. Group B was associated with areas characterized by deep thermoclines (median of 60 m) and low salinities (median of 34.33). Within Group B, two of the three species' responses were consistent with the group pattern; Juan Fernandez petrel differed by occurring more often where thermocline slopes were steep (median of 9.8 deg C m-1). Group C was not associated with any physical habitat variable. This was due to species in the group being associated with different habitats: Leach's storm-petrel with the tropical and equatorial surface water masses and wedge-rumped storm-petrel with waters having shallower thermocline depths (median of 22 m). Overall, two of the three assemblages appeared to be associated with physical habitat during spring with consistency among the species in the group. An association with thermocline depth may indicate that productivity was an important predictor of assemblage presence.

  2. Marine turtles of the Gal?pagos Islands and adjacent areas of the eastern Pacific on the basis of observations made by J.R. Slevin 1905-1906

    USGS Publications Warehouse

    Fritts, T.H.

    1981-01-01

    The field notes of J. R. Slevin written during the expedition of the California Academy of Sciences to the Galapagos Islands in 1905-1096 contain previously unavailable data on the marine turtles of the eastern Pacific. 'Land basking' by green turtles in Galapagos was predominately, if not exclusively, a female behavior. These terrestrial emergences were not concentrated in the major reproductive season of Galapagos turtles. Female Chelonia were also collected on shore during daylight hours on Socorro Island southwest of Baja California, Mexico. Chelonia, green turtles, were observed to feed on seaweed, the leaves and shoots of mangrove trees, and the leaves of another unidentified shoreline shrub. Comparative data on the gonads of dark and yellow turtles indicated that the latter did not breed in Galapagos during Slevin's stay. Lepidochelys olivacea, the olive ridley, was recorded in Galapagos waters and fed on fish eggs

  3. Disease and Injury from Companion Animals.

    ERIC Educational Resources Information Center

    Wishon, Philip M.

    1989-01-01

    Examines the epidemiology, diagnosis, and therapy related to common pet-associated diseases and injuries. Discusses transmission of pet-related health hazards and methods of treatment. Describes preventive measures aimed at safe animal care and control. (RJC)

  4. 76 FR 48184 - Notice of Permit Applications Received Under the Antarctic Conservation Act of 1978

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-08

    ... population biology of the Adelie, Gentoo and Chinstrap penguins, and interactions among these species and..., 1500 Adelie, 2700 Gentoo penguins, 250 Brown skua, 350 South polar skua, 600 Giant petrel, 100...

  5. 76 FR 48183 - Notice of Permit Applications Received Under the Antarctic Conservation Act of 1978

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-08

    ... biology of the Adelie, Gentoo and Chinstrap penguins, and interactions among these species and their..., 2700 Gentoo penguins, 250 Brown skua, 350 South polar skua, 600 Giant petrel, 100 Kelp gulls, 150...

  6. Why do some adult birds skip breeding? A hormonal investigation in a long-lived bird.

    PubMed

    Goutte, Aurélie; Kriloff, Marion; Weimerskirch, Henri; Chastel, Olivier

    2011-10-23

    Skipping reproduction is often observed in long-lived organisms, but proximate mechanisms remain poorly understood. Since young and/or very old snow petrels (Pagodroma nivea) commonly skip breeding, we tested whether they are physiologically able to breed during the pre-laying stage. To do so, we measured the ability of known-age (11-45 years old) petrels to release luteinizing hormone (LH, a crucial driver for breeding), by injecting exogenous gonadotropin-releasing hormone (GnRH). Although young petrels exhibited low baseline LH levels, they were able to elevate LH levels after a GnRH challenge. Moreover, young and very old petrels showed a stronger decrease in LH levels after the 10 min post-GnRH injection compared with middle-aged petrels. Birds that skipped breeding were as able as breeders to release LH after a GnRH challenge, indicating that they had functional pituitaries. However, the decision to skip reproduction was linked to a strong LH decrease after the 10 min post-GnRH injection. Our result suggests that the youngest and the oldest petrels fail to maintain elevated baseline LH levels, thereby do not initiate reproductive activities. Skipping reproduction in long-lived birds probably results from age-related changes in the dynamics of the hypothalamic-pituitary-gonadal (HPG) axis function.

  7. Hydrothermal vent clam and tube worm /sup 13/C//sup 12/C: further evidence of nonphotosynthetic food sources

    SciTech Connect

    Rau, G.H.

    1981-07-17

    The stable carbon isotope ratios in clam mantle tissues taken from both Galapagos and 21/sup 0/N hydrothermal vent sites were similar to the unusually low ratios of carbon-13 to carbon-12 previously reported for a Galapagos hydrothermal vent mussel. In marked contrast to these bivalues, vestimentiferan worm tissues from a Galapagos vent had isotope ratios that were higher than those of open ocean biota. These observations suggest that more than one nonpelagic and nonphotosynthetic carbon fixation pathway is of nutritional importance to vent animals, and that at least one of these pathways is common to two geographically separated vent sites.

  8. 78 FR 56924 - Endangered Species; Receipt of Applications for Permit

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-16

    ... Heads of Executive Departments and Agencies of January 21, 2009--Transparency and Open Government (74 FR... 17.21(g) to include the Galapagos tortoise (Chelonoidis nigra) to enhance their propagation...

  9. Two new combinations in neotropical Eccopsis Zeller, 1852 and one in Megalota Diakonoff, 1966 (Tortricidae: Olethruetinae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polychrosis arenacea Meyrick, 1917 and Polychrosis oxymochla Meyrick, 1917 are transferred to Eccopsis, resulting in two new combinations: Eccopsis arenacea (Meyrick) and Eccopsis oxymochla (Meyrick). In the New World, Eccopsis is recorded from Colombia, Ecuador (including the Galapagos Islands), Pe...

  10. Evolutionary divergency of giant tortoises in Gal?pagos

    USGS Publications Warehouse

    Fritts, T.H.

    1984-01-01

    The giant tortoises in the Galapagos Archipelago diverge considerably in size, and in shape and other carapace characteristics. The saddleback morphotype is known only from insular faunas lacking large terrestrial predators (i.e. Galapagos and Mauritius) and in Galapagos is associated with xeric habitats where vertical feeding range and vertical reach in agonistic encounters are adaptive. The large domed morphotype is associated with relatively cool, mesic habitats where intraspecific competition for food and other resources may be less intense than in xeric habitats. Other external characteristics that differ between tortoise populations are also correlated with ecological variation. Tortoises have radiated into a mosaic of ecological conditions in the Galapagos but critical data are lacking on the role of genetic and environmental controls on phenotypic variation. Morphological divergence in tortoises is potentially a better indicator of present ecological conditions than of evolutionary relationships.

  11. Palaeomagnetism, Potassium-argon ages and petrology of some volcanic rocks

    USGS Publications Warehouse

    Dalrymple, G.B.; Cox, A.

    1968-01-01

    Geological evidence obtained from samples of rocks from Cocos Island, Costa Rica, seems to agree with the idea that this island could have been a stepping stone for organisms migrating to the Galapagos Islands. ?? 1968 Nature Publishing Group.

  12. Metal dynamics in an Antarctic food chain.

    PubMed

    Nygård, T; Lie, E; Røv, N; Steinnes, E

    2001-07-01

    The concentrations of copper, zinc, cadmium, selenium and mercury were determined in eggs, muscle, liver, kidney and stomach content of nestilings and adults of the Antarctic petrel, Thalassoica antarctica, and its predator, the south polar skua, Chataracta maccormicki, from Svarthamaren, Dronning Maud Land, Antarctica. The dominant food of the petrels is krill, Euphausia superba. The results show relatively high levels of cadmium in krill, which is assumed to be the main reason for the high levels of cadmium in petrels and skuas. Cadmium is almost absent in eggs, but accumulates very rapidly with age in nestlings. The copper concentrations in livers of nestling petrels reach very high levels during growth. This may be seen in connection with physiological development processes. Mercury seems to be accumulated with age and between trophic levels. Among the nestlings, the mercury levels decrease with increasing age, which may be accomplished by the excretion of mercury through the growth of feathers and as a dilution effect during growth. Selenium and mercury are inversely correlated in nestlings. The levels of zinc were similar for different nestling stages and between nestlings and adults in skuas and petrels. PMID:11488240

  13. A comparison of the olfactory abilities of three species of procellariiform chicks.

    PubMed

    Cunningham, Gregory B; Van Buskirk, Richard W; Bonadonna, Francesco; Weimerskirch, Henri; Nevitt, Gabrielle A

    2003-05-01

    Most studies investigating olfactory sensitivities in procellariiform seabirds have concentrated on adults, but little attention has been paid to how olfactory behaviours develop. We took a first step towards understanding the ontogeny of these behaviours by testing the olfactory abilities of the blue petrel Halobaena caerulea, the thin-billed prion Pachyptila belcheri, and the common diving petrel Pelecanoides urinatrix. We scored the responsiveness of chicks in a sleep-like state to puffs of odours presented near their nostrils. We tested reactions to dimethyl sulphide (DMS, a prey-related odourant) and phenyl ethyl alcohol (PEA, a novel odourant); distilled water was used as a control. Scores for blue petrel chicks were significantly greater for DMS and PEA than for control presentations, while scores for thin-billed prions were significantly greater only for PEA. Common diving petrels did not respond significantly to either odourant. These results are consistent with what is known of adult olfactory behaviours. A negative correlation between the mass of blue petrel chicks and their mean responsiveness to odours indicates that older or recently fed birds are less responsive to these stimuli. PMID:12682093

  14. Organochlorine residues and shell thinning in Oregon seabird eggs

    USGS Publications Warehouse

    Henny, C.J.; Blus, L.J.; Prouty, R.M.

    1982-01-01

    A single egg was collected at 62 nests of 10 seabird species from Oregon in 1979. The eggs were analyzed for organochlorine contaminants; contemporary shell thickness was compared with eggshells collected during earlier time periods. Concentrations of DDE and PCB's in 1979 were generally low with the most contaminated species being the Double-crested Cormorant (Phalacrocorax auritus), Leach's Storm Petrel (Oceanodroma leucorhoa), and Forktailed Storm Petrel (O. furcata). Limited eggshell data provide evidence that shell thinning was more severe along the Oregon coast in the 1950's than in 1979. With the possible exception of the Fork-tailed Storm Petrel, the residues in 1979 posed no known threat to the welfare of the species.

  15. Correlating seabird movements with ocean winds: linking satellite telemetry with ocean scatterometry.

    USGS Publications Warehouse

    Adams, Josh; Flora, Stephanie

    2010-01-01

    Satellite telemetry studies of the movements of seabirds are now common and have revealed impressive flight capabilities and extensive distributions among individuals and species at sea. Linking seabird movements with environmental conditions over vast expanses of the world's open ocean, however, remains difficult. Seabirds of the order Procellariiformes (e.g., petrels, albatrosses, and shearwaters) depend largely on wind and wave energy for efficient flight. We present a new method for quantifying the movements of far-ranging seabirds in relation to ocean winds measured by the SeaWinds scatterometer onboard the QuikSCAT satellite. We apply vector correlation (as defined by Crosby et al. in J Atm Ocean Tech 10:355-367, 1993) to evaluate how the trajectories (ground speed and direction) for five procellariiform seabirds outfitted with satellite transmitters are related to ocean winds. Individual seabirds (Sooty Shearwater, Pink-footed Shearwater, Hawaiian Petrel, Grey-faced Petrel, and Black-footed Albatross) all traveled predominantly with oblique, isotropic crossing to quartering tail-winds (i.e., 105-165 degrees in relation to birds' trajectory). For all five seabirds, entire track line trajectories were significantly correlated with co-located winds. Greatest correlations along 8-day path segments were related to wind patterns during birds' directed, long-range migration (Sooty Shearwater) as well as movements associated with mega-scale meteorological phenomena, including Pacific Basin anticyclones (Hawaiian Petrel, Grey-faced Petrel) and eastward-propagating north Pacific cyclones (Black-footed Albatross). Wind strength and direction are important factors related to the overall movements that delineate the distribution of petrels at sea. We suggest that vector correlation can be used to quantify movements for any marine vertebrate when tracking and environmental data (winds or currents) are of sufficient quality and sample size. Vector correlation coefficients

  16. Anatomy of a Pathological Mantle Plume

    NASA Astrophysics Data System (ADS)

    Harpp, K. S.; Geist, D. J.

    2008-12-01

    Our understanding of the Galapagos mantle plume has evolved over the past 15 years, largely as a result of the integration of geochemical and geophysical studies carried out at increasingly detailed spatial scales. Pioneering isotopic studies by Bill White and his colleagues revealed that enriched material was concentrated on the north, west, and south edges of the archipelago in an east-facing horseshoe. This, coupled with consideration of novel fluid dynamic models, resulted in the bent plume hypothesis (White et al., 1993), in which the relatively weak Galapagos plume is tilted in the direction of plate motion by shear forces generated by the movement of the overlying plate. The drag of the plate was thought to cause progressive entrainment of the upper mantle as the plume spread to the east. Subsequent sampling of seamounts on the Galapagos platform complicated our understanding of the plume, and indicated that the northern Galapagos Islands and seamounts could not be incorporated into the bent plume model. Instead, this area is best explained as a distinct province from the main archipelago, whose origin primarily results from the flow of material from the plume toward the Galapagos Spreading Center. Furthermore, the northern margin of the plume is defined by Wolf volcano, where the lithospheric cap controls melting conditions. The southern edge of the plume is characterized by rejuvenescent volcanism at Floreana Island. This activity has been attributed to metasomatized rocks in the plume that are only detectable where melting is limited to shallow mantle depths at the cooler margin of the plume. Xenoliths from Floreana indicate that it formerly had the isotopic signature of the western Galapagos. Several lines of evidence point to the plume center being located near Fernandina volcano, including high 3He/4He signals observed in both subaerial and submarine lavas from Fernandina and seismic tomographic studies. These seismic studies delineate the ascending

  17. Differences in straggling rates between two genera of dove lice (Insecta: Phthiraptera) reinforce population genetic and cophylogenetic patterns.

    PubMed

    Whiteman, Noah Kerness; Santiago-Alarcon, Diego; Johnson, Kevin P; Parker, Patricia G

    2004-09-01

    Differences in dispersal abilities have been implicated for causing disparate evolutionary patterns between Columbicola and Physconelloides lice (Insecta: Phthiraptera). However, no study has documented straggling (when lice are found on atypical hosts) rates within these lineages. We used the fact that the Galapagos Hawk, Buteo galapagoensis (Gould) (Falconiformes) feeds on the Galapagos Dove Zenaida galapagoensis Gould (Columbiformes) within an ecologically simplified setting. The Galapagos Dove is the only typical host of Columbicola macrourae (Wilson) and Physconelloides galapagensis (Kellogg and Huwana) in Galapagos. We quantitatively sampled and found these lice on both bird species. A DNA barcoding approach confirmed that stragglers were derived from Galapagos doves. We also collected a Bovicola sp. louse, likely originating from a goat (Capra hircus). On hawks, C. macrourae was significantly more prevalent than P. galapagensis. On doves, the two lice were equally prevalent and abundant. Differences in prevalence on hawks was a function of differences in straggling rate between lice, and not a reflection of their relative representation within the dove population. This provides further evidence that differences in dispersal abilities may drive differences in the degree of cospeciation in Columbicola and Phyconelloides lice, which have become model systems in evolutionary biology.

  18. Individual odor recognition in procellariiform chicks: potential role for the major histocompatibility complex.

    PubMed

    O'Dwyer, Terence W; Nevitt, Gabrielle A

    2009-07-01

    Since the groundbreaking work of Wenzel, Bang, and Grubb in the 1960s, enormous progress has been made toward elucidating the sense of smell in procellariiform seabirds. Although it is now well established that adult procellariiforms use olfaction in many behaviors, such as for foraging, nest relocation, and mate recognition, the olfactory abilities of petrel chicks are less well understood. Recent studies have shown that petrel chicks can recognize prey-related odors and odors associated with their nest before leaving their burrow for the first time. The recognition of burrow odors by petrel chicks is unlikely to be used for homing, and we have suggested that chicks may be learning personal odors associated with the nest's occupants for use later in life in the context of kin recognition or mate choice. The source of personal odors in petrels is unknown. However, in other vertebrates, the major histocompatibility complex influences body odors, which in turn influence mating preferences. It is not currently known whether this highly polymorphic gene region influences body odors and individual recognition in the procellariiforms, but this could be a fruitful area of future research. PMID:19686174

  19. Summary of the 1957-1982 UK scientific research sounding rocket programme

    NASA Astrophysics Data System (ADS)

    Delury, J. T.

    1983-06-01

    The Skylark, Petrel, Fulmar and Skua sounding rockets are described and over 750 flights using these rockets are summarized. Astrophysical and solar-terrestrial physics phenomena; the magnetosphere; space plasmas; and neutral winds were studied. Rockets were also used for X-ray astronomy.

  20. Chemical kin label in seabirds.

    PubMed

    Célérier, Aurélie; Bon, Cécile; Malapert, Aurore; Palmas, Pauline; Bonadonna, Francesco

    2011-12-23

    Chemical signals yield critical socio-ecological information in many animals, such as species, identity, social status or sex, but have been poorly investigated in birds. Recent results showed that chemical signals are used to recognize their nest and partner by some petrel seabirds whose olfactory anatomy is well developed and which possess a life-history propitious to olfactory-mediated behaviours. Here, we investigate whether blue petrels (Halobaena caerulea) produce some chemical labels potentially involved in kin recognition and inbreeding avoidance. To overcome methodological constraints of chemical analysis and field behavioural experiments, we used an indirect behavioural approach, based on mice olfactory abilities in discriminating odours. We showed that mice (i) can detect odour differences between individual petrels, (ii) perceive a high odour similarity between a chick and its parents, and (iii) perceive this similarity only before fledging but not during the nestling developmental stage. Our results confirm the existence of an individual olfactory signature in blue petrels and show for the first time, to our knowledge, that birds may exhibit an olfactory kin label, which may have strong implications for inbreeding avoidance. PMID:21525047

  1. The United Kingdom rocket and balloon program

    NASA Astrophysics Data System (ADS)

    Delury, J. T.

    1980-06-01

    The United Kingdom civilian scientific balloon and rocket program for 1979, 1980, 1981 are summarized and the areas of scientific interest for the period 1981 to 1985 are mentioned. Ten balloons up to 40 cu m to be launched from the USA or Australia and launches of up to ten 7.5 in. diameter Petrel rockets are planned.

  2. Visual fields and foraging in procellariiform seabirds: sensory aspects of dietary segregation.

    PubMed

    Martin, G R; Prince, P A

    2001-01-01

    Retinal visual fields were determined using an ophthalmoscopic reflex technique in two seabird species of the family Procellariidae: white-chinned petrel Procellaria aequinoctialis and antarctic prion Pachyptila desolata. The binocular fields of both species show a similar shape but they differ in size and in the position of the bill within the field. In white-chinned petrels the binocular field extends vertically through approximately 140 degrees and has a maximum width of approximately 40 degrees. The bill is placed approximately central within the field. The binocular field of the prions is approximately half this width and vertical extent, and the bill is placed close to the ventral edge. These differences in binocular field topography can be correlated with the different foraging techniques that these birds employ when seeking a similar diet within the same environment. White-chinned petrels pursue individual items both at the surface and while diving to moderate depths. Antarctic prions feed primarily by filtering items from surface waters. These differences in visual field topography mirror those found in different terrestrial bird species that primarily employ visual or tactile cues in the pursuit of food items. White-chinned petrel eyes and visual fields show features of an amphibious optical design similar to those found in penguins and albatrosses. PMID:11359046

  3. When rediscovery is not enough: taxonomic uncertainty hinders conservation of a critically endangered bird.

    PubMed

    Robertson, Bruce C; Stephenson, Brent M; Goldstien, Sharyn J

    2011-12-01

    In 2003, birds similar to the extinct New Zealand storm-petrel Oceanites maorianus were observed in Hauraki Gulf NZ, raising the possibility of rediscovery after 150 years. O. maorianus has and continues to be surrounded by taxonomic uncertainty, being variously described as a distinct genus, a distinct species, or merely a plumage variant. This uncertainty has hindered conservation planning and funding for the species. Here we examine the taxonomic identity of the rediscovered birds and museum specimens using phylogenetic analysis of mitochondrial (1143 bp cytochrome b) and nuclear (890 bp β-fibrinogen) genes. Using cytochrome b sequence amplified from the 150+ year old specimens, we found that the extant and museum O. maorianus were the same taxon (0.01 genetic distance), with both differing from all other storm-petrel taxa. Using both genes, we examined the phylogenetic affinities of O. maorianus to the Oceanitinae and Hydrobatinae storm-petrels finding that O. maorianus was more closely aligned to Fregetta (0.08-0.09) than Oceanites (0.11-0.12), thereby confirming its status as a distinct taxon, not a plumage variant of O. oceanicus. Our analysis verifies that the previously presumed extinct New Zealand storm-petrel has been rediscovered and can now be assigned a conservation priority commensurate with its critically endangered status. PMID:21855642

  4. Visual fields and foraging in procellariiform seabirds: sensory aspects of dietary segregation.

    PubMed

    Martin, G R; Prince, P A

    2001-01-01

    Retinal visual fields were determined using an ophthalmoscopic reflex technique in two seabird species of the family Procellariidae: white-chinned petrel Procellaria aequinoctialis and antarctic prion Pachyptila desolata. The binocular fields of both species show a similar shape but they differ in size and in the position of the bill within the field. In white-chinned petrels the binocular field extends vertically through approximately 140 degrees and has a maximum width of approximately 40 degrees. The bill is placed approximately central within the field. The binocular field of the prions is approximately half this width and vertical extent, and the bill is placed close to the ventral edge. These differences in binocular field topography can be correlated with the different foraging techniques that these birds employ when seeking a similar diet within the same environment. White-chinned petrels pursue individual items both at the surface and while diving to moderate depths. Antarctic prions feed primarily by filtering items from surface waters. These differences in visual field topography mirror those found in different terrestrial bird species that primarily employ visual or tactile cues in the pursuit of food items. White-chinned petrel eyes and visual fields show features of an amphibious optical design similar to those found in penguins and albatrosses.

  5. 78 FR 62523 - Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To List Ashy Storm...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-22

    ... Distinct Vertebrate Population Segments Under the Endangered Species Act (61 FR 4722, February 7, 1996... Finding on a Petition To List Ashy Storm-Petrel as an Endangered or Threatened Species AGENCY: Fish and... homochroa) as an endangered or threatened species and to designate critical habitat under the...

  6. Upwelling of hydrothermal solutions through ridge flank sediments shown by pore water profiles

    SciTech Connect

    Maris, C.R.P.; Bender, M.L.

    1982-05-07

    High calcium ion and low magnesium ion concentrations in sediment pore waters in cores from the Galapagos Mounds Hydrothermal Field on the flank of the Galapagos Spreading Center are believed to be due to a calcium-magnesium exchange reaction between circulating seawater and basement basalt. The nonlinearity of the calcium ions and magnesium ion gradients indicates that these discharging hydrothermal solutions on the ridge flank are upwelling at the rate of about 1 centimeter per year through the pelagic sediments of the Mounds Field and at about 20 centimeters per year through the hydrothermal mounds themselves.

  7. The distribution of seabirds and pinnipeds in Marguerite Bay and their relationship to physical features during austral winter 2001

    NASA Astrophysics Data System (ADS)

    Chapman, Erik W.; Ribic, Christine A.; Fraser, William R.

    2004-08-01

    The distribution of seabirds and pinnipeds and their relationship to physical oceanographic variables were investigated as part of the US Southern Ocean Global Ocean Ecosystem Dynamics field program along a study grid centered around Marguerite Bay on the west Antarctic Peninsula during late fall (April-May) and winter (July-August), 2001. Sea-ice conditions during the cruises provided an opportunity to compare the relationship among physical oceanographic variables and species distributions before and after the development of pack ice. During the fall cruise before pack ice development, both sea-ice-affiliated species and open-water-affiliated were observed in the area. The most common ice-affiliated species observed at this time were snow petrel ( Pagodroma nivea, 0.7 individuals km -2) and Antarctic petrel ( Thalassoica antarctica, 0.2 individuals km -2) and the most common open-water-affiliated species were blue petrel ( Halobaena caerulea, 0.4 individuals km -2), cape petrel ( Daption capense, 0.2 individuals km -2), and southern fulmar ( Fulmarus glacialoides, 0.1 individuals km -2). In addition, Antarctic fur seals ( Arctocephalus gazella, 0.1 individuals km -2) and crabeater seals ( Lobodon carcinophagus, 0.4 individuals km -2) were observed in low numbers. Akaike's information criterion was used to assess competing models that predicted predator distributions based on physical oceanographic variables proposed to structure predator distribution in previous research. These analyses indicated that predator distributions were primarily associated with water-mass structure and variability in bottom depth during the fall cruise. Crabeater seal, snow petrel, Antarctic petrel, and southern fulmar had higher densities in Inner Shelf Water, particularly near Alexander Island where a coastal current was present. Blue petrel, kelp gull ( Larus dominicanus), and southern giant petrel ( Macronectes giganteus) were positively associated with variability in bottom depth

  8. The distribution of seabirds and pinnipeds in Marguerite Bay and their relationship to physical features during austral winter 2001

    USGS Publications Warehouse

    Chapman, Erik W.; Ribic, C.A.; Fraser, William R.

    2004-01-01

    The distribution of seabirds and pinnipeds and their relationship to physical oceanographic variables were investigated as part of the US Southern Ocean Global Ocean Ecosystem Dynamics field program along a study grid centered around Marguerite Bay on the west Antarctic Peninsula during late fall (April-May) and winter (July-August), 2001. Sea-ice conditions during the cruises provided an opportunity to compare the relationship among physical oceanographic variables and species distributions before and after the development of pack ice. During the fall cruise before pack ice development, both sea-ice-affiliated species and open-water-affiliated were observed in the area. The most common ice-affiliated species observed at this time were snow petrel (Pagodroma nivea, 0.7 individuals km-2) and Antarctic petrel (Thalassoica antarctica, 0.2 individuals km-2) and the most common open-water-affiliated species were blue petrel (Halobaena caerulea, 0.4 individuals km-2), cape petrel (Daption capense, 0.2 individuals km-2), and southern fulmar (Fulmarus glacialoides, 0.1 individuals km-2). In addition, Antarctic fur seals (Arctocephalus gazella, 0.1 individuals km-2) and crabeater seals (Lobodon carcinophagus, 0.4 individuals km-2) were observed in low numbers. Akaike's information criterion was used to assess competing models that predicted predator distributions based on physical oceanographic variables proposed to structure predator distribution in previous research. These analyses indicated that predator distributions were primarily associated with water-mass structure and variability in bottom depth during the fall cruise. Crabeater seal, snow petrel, Antarctic petrel, and southern fulmar had higher densities in Inner Shelf Water, particularly near Alexander Island where a coastal current was present. Blue petrel, kelp gull (Larus dominicanus), and southern giant petrel (Macronectes giganteus) were positively associated with variability in bottom depth in April

  9. National Audubon Society Specials. Teacher's Guide I.

    ERIC Educational Resources Information Center

    WETA - TV, Washington, DC.

    Since no civilization can survive without a healthy environment, people must learn to live in harmony with their natural ecosystems and build for future generations. This guide describes six award-winning programs on the condor, black-footed ferret, panthers and cheetahs, ducks, farming and wildlife, and the Galapagos Islands. Although each…

  10. The causes of evolutionary radiations in archipelagoes: passerine birds in the Lesser Antilles.

    PubMed

    Ricklefs, Robert E; Bermingham, Eldredge

    2007-03-01

    To investigate why some lineages undergo evolutionary radiation, we compare the passerine avifaunas of the Hawaiian and Galapagos archipelagoes, which have supported well-known radiations of birds, with those of the Lesser Antilles, which have not. We focus on four steps required for the buildup of diversity through allopatric speciation and secondary sympatry: genetic divergence in isolation, persistence of island populations, recolonization of source islands, and ecological compatibility in secondary sympatry. Analysis of genetic divergence among island populations in the Lesser Antilles reveals evidence of both prolonged independent evolution and re-expansion of differentiated island populations through the archipelago but little evidence of secondary sympatry of divergent genetic lineages. Archipelagoes with high rates of colonization from continental or nearby large-island sources might fail to promote evolutionary radiations because colonists fill ecological space and constrain diversification through competition. However, morphological analysis demonstrated similar divergence between allopatric populations in species in Hawaii, Galapagos, and the Lesser Antilles, although the rate of divergence between secondarily sympatric species evidently is more rapid in Hawaii and the Galapagos. Alternatively, endemic buildup of diversity might be facilitated by the relative absence of pathogens in Hawaii and Galapagos that otherwise could prevent the secondary sympatry of populations owing to disease-mediated competition. PMID:17230401

  11. 76 FR 66954 - Endangered Species; Receipt of Applications for Permit

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-28

    ... registration under 50 CFR 17.21(g) for radiated tortoise (Astrochelys radiata) to enhance their propagation or.... Families: Bovidae. Equidae. Psittacidae. Crocodilidae. Species: Galapagos tortoise (Chelonoides nigra). radiated tortoise (Astrochelys radiata). Red-crowned crane (Grus japonica). ring-tailed lemur (Lemur...

  12. The causes of evolutionary radiations in archipelagoes: passerine birds in the Lesser Antilles.

    PubMed

    Ricklefs, Robert E; Bermingham, Eldredge

    2007-03-01

    To investigate why some lineages undergo evolutionary radiation, we compare the passerine avifaunas of the Hawaiian and Galapagos archipelagoes, which have supported well-known radiations of birds, with those of the Lesser Antilles, which have not. We focus on four steps required for the buildup of diversity through allopatric speciation and secondary sympatry: genetic divergence in isolation, persistence of island populations, recolonization of source islands, and ecological compatibility in secondary sympatry. Analysis of genetic divergence among island populations in the Lesser Antilles reveals evidence of both prolonged independent evolution and re-expansion of differentiated island populations through the archipelago but little evidence of secondary sympatry of divergent genetic lineages. Archipelagoes with high rates of colonization from continental or nearby large-island sources might fail to promote evolutionary radiations because colonists fill ecological space and constrain diversification through competition. However, morphological analysis demonstrated similar divergence between allopatric populations in species in Hawaii, Galapagos, and the Lesser Antilles, although the rate of divergence between secondarily sympatric species evidently is more rapid in Hawaii and the Galapagos. Alternatively, endemic buildup of diversity might be facilitated by the relative absence of pathogens in Hawaii and Galapagos that otherwise could prevent the secondary sympatry of populations owing to disease-mediated competition.

  13. A Quest for Knowledge.

    ERIC Educational Resources Information Center

    Mason, Mary Teague

    1999-01-01

    Discusses the use of Quest, an internet activity that encourages higher-order thinking. Led by Dan Buettner and his team of "adventurers," students can tour with the Quest team as they explore different countries (AsiaQuest, MayaQuest, AfricaQuest, and GalapagosQuest). Provides examples of how three different teachers utilized Quest. (CMK)

  14. Origins and diversity of a cosmopolitan fern genus on an island archipelago

    PubMed Central

    Wolf, Paul G.; Rowe, Carol A.; Der, Joshua P.; Schilling, Martin P.; Visger, Clayton J.; Thomson, John A.

    2015-01-01

    Isolated oceanic islands are characterized by patterns of biological diversity different from that on nearby continental mainlands. Isolation can provide the opportunity for evolutionary divergence, but also set the stage for hybridization between related taxa arriving from different sources. Ferns disperse by haploid spores, which are produced in large numbers and can travel long distances in air currents, enabling these plants to become established on most oceanic islands. Here, we examine the origins and patterns of diversity of the cosmopolitan fern genus Pteridium (Dennstaedtiaceae; bracken) on the Galapagos Islands. We use nucleotide sequences from two plastid genes, and two nuclear gene markers, to examine phylogeography of Pteridium on the Galapagos Islands. We incorporate data from a previous study to provide a worldwide context. We also sampled new specimens from South and Central America. We used flow cytometry to estimate genome size of some accessions. We found that both plastid and nuclear haplotypes fall into two distinct clades, consistent with a two-diploid-species taxonomy of P. aquilinum and P. esculentum. As predicted, the allotetraploid P. caudatum possesses nuclear haplotypes from both diploid species. Samples from the Galapagos include P. esculentum subsp. arachnoideum, P. caudatum and possible hybrids between them. Multiple Pteridium taxa were also observed growing together at some sites. We find evidence for multiple origins of Pteridium on the Galapagos Islands and multiple origins of tetraploid P. caudatum throughout its range in Central and South America. We also posit that P. caudatum may include recent diploid hybrids, backcrosses to P. esculentum, as well as allotetraploid plants. The Galapagos Islands are positioned close to the equator where they can receive dispersing propagules from both hemispheres. This may partly explain the high levels of diversity found for this cosmopolitan fern on these islands. PMID:26487677

  15. Inverse modeling of Central American lavas: old lithospheric and young asthenospheric heterogeneities

    NASA Astrophysics Data System (ADS)

    Feigenson, M.; Gazel, E.; Carr, M. J.

    2009-12-01

    In recent years, there have been a number of models proposed to account for the OIB-like geochemical characteristics of lavas from central Costa Rica. The source for most basalts of the Central American volcanic front (ranging from Guatemala to northern Costa Rica) is dominantly DM (depleted MORB-source mantle) fluxed by subduction-derived fluids. In contrast, central Costa Rican basalts display striking isotopic similarities to the Galapagos hotspot. How the Galapagos signature is introduced into the Central American source is at the heart of the conflicting theories. Several models incorporate asthenospheric flow of this enriched mantle, either around the Central American arc via South America, or through a slab window, which may have opened about 5 my ago beneath central Costa Rica. Alternatively, passage of the Caribbean plate over the Galapagos hotspot may have left veins of unerupted melt within the sub-Caribbean lithosphere. These veins may be preferentially tapped during later superimposed arc volcanism. Although these models yield identical isotopic systematics, it may be possible to distinguish between them by a geochemical technique that can indicate the presence of garnet in the source region. This method, developed by Hofmann and coworkers in the 1980s, is termed inverse modeling, and uses the variation of REEs in lavas to assess the relative importance of garnet vs. clinopyroxene during partial melting. We have applied this method to new REE data from back arc lavas throughout Central America, and preliminary results indicate that garnet is not present in their sources. In contrast, direct slab melts (adakites) from Central America, as well as volcanic front lavas and alkaline basalt (with minimal slab signature) from central Costa Rica and Panama, require a source with garnet. Therefore, enriched mantle in the back arc is likely stored in the shallow lithosphere rather than introduced through asthenospheric flow. Enriched material in the volcanic

  16. Predicting sea-level rise vulnerability of terrestrial habitat and wildlife of the Northwestern Hawaiian Islands

    USGS Publications Warehouse

    Reynolds, Michelle H.; Berkowitz, Paul; Courtot, Karen N.; Krause, Crystal M.; Reynolds, Michelle H.; Berkowitz, Paul; Courtot, Karen N.; Krause, Crystal M.

    2012-01-01

    emphasize the need for early climate change adaptation and mitigation planning, especially for species with limited breeding distributions and/or ranges restricted primarily to the low-lying NWHI: Cyperus pennatiformis var. bryanii, Black-footed Albatross (Phoebastria nigripes), Laysan Albatross (P. immutabilis), Bonin Petrel (Pterodroma hypoleuca), Gray-backed Tern (Onychoprion lunatus), Laysan Teal (Anas laysanensis), Laysan Finch (Telespiza cantans), and Hawaiian monk seal (Monachus schauinslandi). Furthermore, SLR scenarios that include the effects of wave dynamics and groundwater rise may indicate amplified vulnerability to climate change driven habitat loss on low-lying islands. In chapter 2, we incorporated the combined effects of SLR, dynamic wave-driven inundation, and rising groundwater in a quantitative study specifically for the Laysan Island ecosystem. This is the first hydrodynamic model to simulate the combined impacts of SLR and wave-driven inundation in the NWHI. We developed a high-resolution digital elevation model (mean vertical accuracy of 0.32 m) for the island. Then using recent satellite imagery, geospatial models, and historical oceanographic, storm, and biological data we estimated potential inundation extent, habitat loss, and wildlife population impacts for a range of potential SLR scenarios (0.00, +0.50, +1.00, +1.50, and +2.00 m) that may occur over the next century. Additionally, we estimated the carrying capacity of Laysan Island for five species based on the available population monitoring data and described how potential losses in nesting habitat could influence population dynamics for Black-footed Albatross, Laysan Albatross, Red-footed Booby (Sula sula), Laysan Teal, and Laysan Finch. For some other seabird populations (Masked Booby, S. dactylatra; Brown Booby, S. leucogaster; Great Frigatebird, Fregata minor; and Sooty Tern, Onychoprion fuscata), we used recent colony distribution data, land cover maps, and nesting behavior to estimate

  17. Shell thinning and residues of organochlorines and mercury in seabird eggs, Eastern Canada, 1970-76.

    PubMed

    Pearce, P A; Peakall, D B; Reynolds, L M

    1979-09-01

    Organochlorine and mercury concentrations are reported for 252 eggs of Leach's storm-petrel (Oceanodroma leucorhoa), double-crested cormorant (Phalarocorax auritus), common eider (Somateria mollissima), common tern (Sterna hirundo), razorbill (Alca torda), common murre (Uria aalge) black guillemot (Cepphus grylle), and Atlantic puffin (Fratercula arctica) from the Bay of Fundy, the Gulf of St. Lawrence, and the open Atlantic shore of Canada during 1970-76. Concentrations of all organochlorines except DDE and polychlorinated biphenyls (PCBs) were low. DDE, PCBs, and mercury residues were highest in cormorant and petrel, intermediated in alcids, and lowest in eider and tern. Temporal and spatial aspects of contamination patterns are discussed. Authors conclude that only in cormorants were DDE residues high enough to cause, through eggshell thinning, local population declines. PMID:117427

  18. Attraction of Hawaiian seabirds to lights: conservation efforts and effects of moon phase

    USGS Publications Warehouse

    Telfer, T.C.; Sincock, J.L.; Byrd, G.V.; Reed, J.R.

    1987-01-01

    Increased urban lighting on Kauai Island, Hawaii, has resulted in new problems for threatened and endangered procellariiform birds. Between 1978 and 1985,11,767 Kewell's shearwaters, 38 dark-rumped petrels, and 8 band-rumped storm petrels were attracted to bright urban lights, struck unseen objects, and fell to the ground. A salvage effort involving public cooperation and government-run 'aid stations' has returned 90% of these birds to the wild. Nightly fallout of seabirds was significantly reduced during the full moon, but fallout increased as the new moon approached. The heaviest fallout occurred in urban coastal areas, particularly at river mouths. More than 97% of the fallout involved fledgling birds apparently leaving their mountain nesting grounds for the first time. Less than 1%of these birds were recovered again on subsequent nights.

  19. Top predators in relation to bathymetry, ice and krill during austral winter in Marguerite Bay, Antarctica

    NASA Astrophysics Data System (ADS)

    Ribic, Christine A.; Chapman, Erik; Fraser, William R.; Lawson, Gareth L.; Wiebe, Peter H.

    2008-02-01

    A key hypothesis guiding the US Southern Ocean Global Ocean Ecosystems Dynamics (US SO GLOBEC) program is that deep across-shelf troughs facilitate the transport of warm and nutrient-rich waters onto the continental shelf of the Western Antarctic Peninsula, resulting in enhanced winter production and prey availability to top predators. We tested aspects of this hypothesis during austral winter by assessing the distribution of the resident pack-ice top predators in relation to these deep across-shelf troughs and by investigating associations between top predators and their prey. Surveys were conducted July-August 2001 and August-September 2002 in Marguerite Bay, Antarctica, with a focus on the main across-shelf trough in the bay, Marguerite Trough. The common pack-ice seabird species were snow petrel ( Pagodroma nivea, 1.2 individuals km -2), Antarctic petrel ( Thalassoica antarctica, 0.3 individuals km -2), and Adélie penguin ( Pygoscelis adeliae, 0.5 individuals km -2). The most common pack-ice pinniped was crabeater seal ( Lobodon carcinophagus). During both winters, snow and Antarctic petrels were associated with low sea-ice concentrations independent of Marguerite Trough, while Adélie penguins occurred in association with this trough. Krill concentrations, both shallow and deep, also were associated with Adélie penguin and snow petrel distributions. During both winters, crabeater seal occurrence was associated with deep krill concentrations and with regions of lower chlorophyll concentration. The area of lower chlorophyll concentrations occurred in an area with complex bathymetry close to land and heavy ice concentrations. Complex or unusual bathymetry via its influence on physical and biological processes appears to be one of the keys to understanding how top predators survive during the winter in this Antarctic region.

  20. The storm-time equatorial electrojet

    NASA Technical Reports Server (NTRS)

    Burrows, K.; Sastry, T. S. G.; Sampath, S.; Stolarik, J. D.; Usher, M. J.

    1976-01-01

    A Petrel rocket carrying a double cell rubidium magnetometer was launched from the Thumba Equatorial Rocket Launching Station during the early main phase of a magnetic storm. No ionospheric currents associated with the storm were observed and the large field depression, at the flight time, must therefore be attributed to currents at higher altitudes. The equatorial enhancement of ionospheric magnetic storm currents, predicted on the basis of theory and earlier ground data, was not observed.

  1. The storm-time equatorial electrojet

    NASA Technical Reports Server (NTRS)

    Burrows, K.; Sastry, T. S. G.; Sampath, S.; Stolarik, J. D.; Usher, M. J.

    1977-01-01

    A Petrel rocket carrying a double cell rubidium magnetometer was launched from the Thumba Equatorial Rocket Launching Station during the early main phase of a magnetic storm. No ionospheric currents associated with the storm were observed, and the large field depression at the flight time must therefore be attributed to currents at higher altitudes. The equatorial enhancement of ionospheric magnetic storm currents, predicted on the basis of theory and earlier ground data, was not observed.

  2. Heavy metal and metallothionein concentrations in Atlantic Canadian seabirds.

    PubMed

    Elliott, J E; Scheuhammer, A M; Leighton, F A; Pearce, P A

    1992-01-01

    Seabird tissues, collected during the 1988 breeding season from colonies on the Atlantic coast of Canada, were analyzed for toxic metals--Cd, Hg and Pb--and 18 other trace elements. Metallothionein (MT) was measured in kidney, and kidneys and livers underwent histopathological examination. Levels of most essential trace elements appear to be closely regulated in seabird tissues; values were in good agreement with those previously reported in the published literature. Liver-Se concentrations in Leach's storm-petrels (Oceanodroma leukorrhea) (77.6 + 7.49 micrograms/g dry weight) were much higher than values normally reported for free-living birds and mammals. Cd levels varied greatly among individuals, but were always higher in kidney than in liver. Highest mean Cd concentrations (183 + 65 micrograms/g dry weight) were in kidneys of the planktivorous Leach's storm-petrels from the Gulf of St. Lawrence. A few individuals of this species had values greater than 300 micrograms/g dry weight. Cd and metallothionein (MT) concentrations were positively correlated in kidneys of Leach's storm-petrels (r = 0.692), Atlantic puffin (Fratercula arctica) (r = 0.845) and herring gull (Larus argentatus) (r = 0.866). Concentrations of total Hg varied greatly among species and individuals, but were consistently higher in liver than in kidney. Highest mean levels (21 + 28 micrograms/g) were in livers of the piscivorous double-crested cormorant (Phalacrocorax auritus) from Saint John Harbour in the Bay of Fundy. Concentrations of Hg and Se were positively correlated (r = 0.736) in livers of Leach's storm-petrel, but not in other species. Pb concentrations were consistently greatest in bone, with mean levels being highest in herring gulls from a colony in the Bay of Fundy (63 + 36 micrograms/g). Histological examination of liver and kidney failed to reveal indications of tissue damage associated with elevated levels of heavy metals. PMID:1554255

  3. Living close, doing differently: small-scale asynchrony in demography of two species of seabirds.

    PubMed

    Tavecchia, Giacomo; Minguez, Eduardo; De León, Ana; Louzao, Maite; Oro, Daniel

    2008-01-01

    Studies on spatiotemporal pattern of population abundance predict that close populations should exhibit a high level of synchrony, reflected in a parallel time variation of at least one demographic parameter. We tested this prediction for two threatened species of Procellariiformes sharing similar life history traits: the European Storm Petrel (Hydrobates pelagicus) and the Balearic Shearwater (Puffinus mauretanicus). Within each species, we compared adult survival, proportion of transients (breeders that do not settle), and average productivity at two neighboring colonies. Physical and environmental features (e.g., food availability) of the breeding sites were similar. However, while Balearic Shearwater colonies were free of predators, aerial predators occurred especially in one colony of the European Storm Petrel. Despite this difference, we found similar results for the two species. A high proportion of transient birds was detected in only one colony of each species, ranging between 0.00-0.38 and 0.10-0.63 for the petrels and shearwaters, respectively. This seems to be an emergent feature of spatially structured populations of seabirds, unrelated to colony size or predator pressure, that can have important demographic consequences for local population dynamics and their synchrony. Local survival of resident birds was different at each colony, an unexpected result, especially for predator-free colonies of Balearic Shearwater. Productivity varied between the two colonies of European Storm Petrels, but not between the two colonies of Balearic Shearwaters. We demonstrated that within each species, several demographic parameters were colony specific and sufficiently different to generate short-term asynchronous dynamics. Our findings suggest that, in spatially structured populations, local factors, such as predation or small-scale habitat features, or population factors, such as individual quality or age structure, can generate unexpected asynchrony between

  4. Top predators in relation to bathymetry, ice and krill during austral winter in Marguerite Bay, Antarctica

    USGS Publications Warehouse

    Ribic, C.A.; Chapman, E.; Fraser, William R.; Lawson, G.L.; Wiebe, P.H.

    2008-01-01

    A key hypothesis guiding the US Southern Ocean Global Ocean Ecosystems Dynamics (US SO GLOBEC) program is that deep across-shelf troughs facilitate the transport of warm and nutrient-rich waters onto the continental shelf of the Western Antarctic Peninsula, resulting in enhanced winter production and prey availability to top predators. We tested aspects of this hypothesis during austral winter by assessing the distribution of the resident pack-ice top predators in relation to these deep across-shelf troughs and by investigating associations between top predators and their prey. Surveys were conducted July-August 2001 and August-September 2002 in Marguerite Bay, Antarctica, with a focus on the main across-shelf trough in the bay, Marguerite Trough. The common pack-ice seabird species were snow petrel (Pagodroma nivea, 1.2 individuals km-2), Antarctic petrel (Thalassoica antarctica, 0.3 individuals km-2), and Ade??lie penguin (Pygoscelis adeliae, 0.5 individuals km-2). The most common pack-ice pinniped was crabeater seal (Lobodon carcinophagus). During both winters, snow and Antarctic petrels were associated with low sea-ice concentrations independent of Marguerite Trough, while Ade??lie penguins occurred in association with this trough. Krill concentrations, both shallow and deep, also were associated with Ade??lie penguin and snow petrel distributions. During both winters, crabeater seal occurrence was associated with deep krill concentrations and with regions of lower chlorophyll concentration. The area of lower chlorophyll concentrations occurred in an area with complex bathymetry close to land and heavy ice concentrations. Complex or unusual bathymetry via its influence on physical and biological processes appears to be one of the keys to understanding how top predators survive during the winter in this Antarctic region. ?? 2007 Elsevier Ltd. All rights reserved.

  5. Organochlorine contaminants in eggs of seabirds in the Northwest Atlantic, 1968-1984.

    PubMed

    Pearce, P A; Elliott, J E; Peakall, D B; Norstrom, R J

    1989-01-01

    Eggs of three seabird species, double-crested cormorant (Phalacrocorax auritus). Leach's storm-petrel (Oceanodroma leucorhoa), and Atlantic puffin (Fratercula arctica) were collected at four-year intervals from 1968 to 1984, from colonies in eastern Canada and analyzed for organochlorines. This monitoring study was established to provide data on contamination of the marine environment and possible implications for seabird health. Long-term trend data are presented for PCBs, DDE, dieldrin, HCB, oxychlordane, heptachlor epoxide, HCH and mirex. DDE and PCBs declined significantly in all species from the Bay of Fundy. DDE declined significantly in puffins and petrels while PCBs declined only in petrels from the Atlantic coast of Newfoundland. Generally DDE declined more than PCBs. Dieldrin, oxychlordane, HCH and mirex levels decreased at some locations but were stable at others. Hexachlorobenzene and heptachlor epoxide levels remained steady or increased significantly, depending on the species and location. Organochlorine levels in cormorants from the St. Lawrence River estuary showed no significant trends. PMID:15092478

  6. Hierarchical patch dynamics and animal movement pattern.

    PubMed

    Fauchald, Per; Tveraa, Torkild

    2006-09-01

    In hierarchical patch systems, small-scale patches of high density are nested within large-scale patches of low density. The organization of multiple-scale hierarchical systems makes non-random strategies for dispersal and movement particularly important. Here, we apply a new method based on first-passage time on the pathway of a foraging seabird, the Antarctic petrel (Thalassoica antarctica), to quantify its foraging pattern and the spatial dynamics of its foraging areas. Our results suggest that Antarctic petrels used a nested search strategy to track a highly dynamic hierarchical patch system where small-scale patches were congregated within patches at larger scales. The birds searched for large-scale patches by traveling fast and over long distances. Once within a large-scale patch, the birds concentrated their search to find smaller scale patches. By comparing the pathway of different birds we were able to quantify the spatial scale and turnover of their foraging areas. On the largest scale we found foraging areas with a characteristic scale of about 400 km. Nested within these areas we found foraging areas with a characteristic scale of about 100 km. The large-scale areas disappeared or moved within a time frame of weeks while the nested small-scale areas disappeared or moved within days. Antarctic krill (Euphausia superba) is the dominant food item of Antarctic petrels and we suggest that our findings reflect the spatial dynamics of krill in the area. PMID:16794832

  7. Mercury concentrations in breast feathers of three upper trophic level marine predators from the western Aleutian Islands, Alaska.

    PubMed

    Kaler, Robb S A; Kenney, Leah A; Bond, Alexander L; Eagles-Smith, Collin A

    2014-05-15

    Mercury (Hg) is a toxic element distributed globally through atmospheric transport. Agattu Island, located in the western Aleutian Islands, Alaska, has no history of point-sources of Hg contamination. We provide baseline levels of total mercury (THg) concentrations in breast feathers of three birds that breed on the island. Geometric mean THg concentrations in feathers of fork-tailed storm-petrels (Oceanodroma furcata; 6703 ± 1635, ng/g fresh weight [fw]) were higher than all other species, including snowy owl (Bubo scandiacus; 2105 ± 1631, ng/g fw), a raptor with a diet composed largely of storm-petrels at Agattu Island. There were no significant differences in mean THg concentrations of breast feathers among adult Kittlitz's murrelet (Brachyramphus brevirostris; 1658 ± 1276, ng/g fw) and chicks (1475 ± 671, ng/g fw) and snowy owls. The observed THg concentrations in fork-tailed storm-petrel feathers emphasizes the need for further study of Hg pollution in the western Aleutian Islands. PMID:24656750

  8. Seabirds indicate changes in the composition of plastic litter in the Atlantic and south-western Indian Oceans.

    PubMed

    Ryan, Peter G

    2008-08-01

    I compare plastic ingested by five species of seabirds sampled in the 1980s and again in 1999-2006. The numbers of ingested plastic particles have not changed significantly, but the proportion of virgin pellets has decreased 44-79% in all five species: great shearwater Puffinus gravis, white-chinned petrel Procellaria aequinoctialis, broad-billed prion Pachyptila vittata, white-faced storm petrel Pelagodroma marina and white-bellied storm petrel Fregetta grallaria. The populations sampled range widely in the South Atlantic and western Indian Oceans. The most marked reduction occurred in great shearwaters, where the average number of pellets per bird decreased from 10.5 to 1.6. This species migrates between the South and North Atlantic each year. Similar decreases in virgin pellets have been recorded in short-tailed shearwaters Puffinus tenuirostris in the Pacific Ocean and northern fulmars Fulmarus glacialis in the North Sea. More data are needed on the relationship between plastic loads in seabirds and the density of plastic at sea in their foraging areas, but the consistent decrease in pellets in birds suggests there has been a global change in the composition of small plastic debris at sea over the last two decades. PMID:18572198

  9. Demographic effects of extreme weather events: snow storms, breeding success, and population growth rate in a long-lived Antarctic seabird.

    PubMed

    Descamps, Sébastien; Tarroux, Arnaud; Varpe, Øystein; Yoccoz, Nigel G; Tveraa, Torkild; Lorentsen, Svein-Håkon

    2015-01-01

    Weather extremes are one important element of ongoing climate change, but their impacts are poorly understood because they are, by definition, rare events. If the frequency and severity of extreme weather events increase, there is an urgent need to understand and predict the ecological consequences of such events. In this study, we aimed to quantify the effects of snow storms on nest survival in Antarctic petrels and assess whether snow storms are an important driver of annual breeding success and population growth rate. We used detailed data on daily individual nest survival in a year with frequent and heavy snow storms, and long term data on petrel productivity (i.e., number of chicks produced) at the colony level. Our results indicated that snow storms are an important determinant of nest survival and overall productivity. Snow storm events explained 30% of the daily nest survival within the 2011/2012 season and nearly 30% of the interannual variation in colony productivity in period 1985-2014. Snow storms are a key driver of Antarctic petrel breeding success, and potentially population dynamics. We also found state-dependent effects of snow storms and chicks in poor condition were more likely to die during a snow storm than chicks in good condition. This stresses the importance of considering interactions between individual heterogeneity and extreme weather events to understand both individual and population responses to climate change. PMID:25691959

  10. Preliminary assessment of avian stomach oils: a vector of contaminants to chicks and potential for diet analysis and biomonitoring.

    PubMed

    Foster, Karen L; Wang, Shiway W; Mackay, Don; Mallory, Mark L; Blais, Jules M

    2010-09-01

    Bird species from the order Procellariiformes or petrels, including the northern fulmar (Fulmarus glacialis), produce high lipid and high energy content stomach oils from the prey they consume, which enables them to exploit distant marine food sources. Stomach oils are also used as a food source for chicks and for defensive purposes. Samples of stomach oils from two Arctic colonies, St. George Island Alaska, USA and Cape Vera, Devon Island Nunavut, Canada, were collected and analyzed for organochlorine contaminants. SigmaPCB concentrations ranged from 13 to 236 ng g(-1) wet weight (ww) and SigmaDDT concentrations from 5 to 158 ng g(-1) ww and were similar in both sites, though differences in chemical signatures were apparent. Stomach oils are a rich energy source; however, they may also provide a higher dose of contaminants per unit energy than the direct consumption of prey items, as illustrated using mass and energy balance calculations to estimate chick exposure to SigmaDDT for hypothetical stomach oil and whole prey diets. The results of this study suggest that stomach oils are an important vector of organochlorine contaminants to chicks and should be considered in future risk assessments of northern fulmars and other species of petrels. To our knowledge this is the first study of stomach oils as an overlooked vector of organochlorine contaminants to chicks and as a potentially valuable medium for dietary analysis and noninvasive biomonitoring both of petrel dietary exposure and of marine contaminant concentrations. PMID:20707316

  11. Mercury concentrations in breast feathers of three upper trophic level marine predators from the western Aleutian Islands, Alaska

    USGS Publications Warehouse

    Kaler, Robb S.A.; Kenney, Leah A.; Bond, Alexander L.; Eagles-Smith, Collin A.

    2014-01-01

    Mercury (Hg) is a toxic element distributed globally through atmospheric transport. Agattu Island, located in the western Aleutian Islands, Alaska, has no history of point-sources of Hg contamination. We provide baseline levels of total mercury (THg) concentrations in breast feathers of three birds that breed on the island. Geometric mean THg concentrations in feathers of fork-tailed storm-petrels (Oceanodroma furcata; 6703 ± 1635, ng/g fresh weight [fw]) were higher than all other species, including snowy owl (Bubo scandiacus; 2105 ± 1631, ng/g fw), a raptor with a diet composed largely of storm-petrels at Agattu Island. There were no significant differences in mean THg concentrations of breast feathers among adult Kittlitz’s murrelet (Brachyramphus brevirostris; 1658 ± 1276, ng/g fw) and chicks (1475 ± 671, ng/g fw) and snowy owls. The observed THg concentrations in fork-tailed storm-petrel feathers emphasizes the need for further study of Hg pollution in the western Aleutian Islands.

  12. Demographic effects of extreme weather events: snow storms, breeding success, and population growth rate in a long-lived Antarctic seabird

    PubMed Central

    Descamps, Sébastien; Tarroux, Arnaud; Varpe, Øystein; Yoccoz, Nigel G; Tveraa, Torkild; Lorentsen, Svein-Håkon

    2015-01-01

    Weather extremes are one important element of ongoing climate change, but their impacts are poorly understood because they are, by definition, rare events. If the frequency and severity of extreme weather events increase, there is an urgent need to understand and predict the ecological consequences of such events. In this study, we aimed to quantify the effects of snow storms on nest survival in Antarctic petrels and assess whether snow storms are an important driver of annual breeding success and population growth rate. We used detailed data on daily individual nest survival in a year with frequent and heavy snow storms, and long term data on petrel productivity (i.e., number of chicks produced) at the colony level. Our results indicated that snow storms are an important determinant of nest survival and overall productivity. Snow storm events explained 30% of the daily nest survival within the 2011/2012 season and nearly 30% of the interannual variation in colony productivity in period 1985–2014. Snow storms are a key driver of Antarctic petrel breeding success, and potentially population dynamics. We also found state-dependent effects of snow storms and chicks in poor condition were more likely to die during a snow storm than chicks in good condition. This stresses the importance of considering interactions between individual heterogeneity and extreme weather events to understand both individual and population responses to climate change. PMID:25691959

  13. Risk factors for carriage of antimicrobial-resistant Salmonella spp and Escherichia coli in pet dogs from volunteer households in Ontario, Canada, in 2005 and 2006.

    PubMed

    Leonard, Erin K; Pearl, David L; Janecko, Nicol; Finley, Rita L; Reid-Smith, Richard J; Weese, J Scott; Peregrine, Andrew S

    2015-11-01

    OBJECTIVE To determine pet-related management factors associated with the carriage of antimicrobial-resistant Salmonella spp and Escherichia coli in a population of pet dogs. SAMPLE 138 dogs from 84 households in Ontario, Canada. PROCEDURES From October 2005 through May 2006, dogs and households in Ontario, Canada, were recruited to participate in a cross-sectional study. Fecal samples were submitted for culture of Salmonella spp and E coli, which provided 515 bacterial isolates for antimicrobial susceptibility testing. Multilevel logistic regression models with random effects for household and dog were created to identify pet-related management factors associated with antimicrobial resistance. RESULTS Bacterial species, feeding a homemade diet or adding homemade food to the diet, feeding a raw diet or adding anything raw to the diet, feeding a homemade raw food diet, and feeding raw chicken in the past week were significant risk factors for antimicrobial resistance in this population of dogs. CONCLUSIONS AND CLINICAL RELEVANCE In this study, several potentially important pet-related risk factors for the carriage of antimicrobial-resistant Salmonella spp and E coli in pet dogs were identified. Further evaluation of risk factors for antimicrobial resistance in dogs may lead to development of evidence-based guidelines for safe and responsible dog ownership and management to protect the public, especially pet owners who are immunocompromised.

  14. Characterization of single nucleotide polymorphism markers for the green sea turtle (Chelonia mydas).

    PubMed

    Roden, Suzanne E; Dutton, Peter H; Morin, Phillip A

    2009-05-01

    We present data on 29 new single nucleotide polymorphism assays for the green sea turtle, Chelonia mydas. DNA extracts from 39 green turtles were used for two methods of single nucleotide polymorphism discovery. The first approach employed an amplified fragment length polymorphism technique. The second technique screened a microsatellite library. Allele-specific amplification assays were developed for high-throughput single nucleotide polymorphism genotyping and tested on two Pacific C. mydas nesting populations. Observed heterozygosities ranged from 0 to 0.95 for a Hawaiian population and from 0 to 0.85 for a Galapagos population. Each of the populations had one locus out of Hardy-Weinberg equilibrium, SSCM2b and SSCM5 for Hawaii and Galapagos, respectively. No loci showed significant genotypic linkage disequilibrium across an expanded set of four Pacific nesting populations. However, two loci, SSCM4 and SSCM10b showed linkage disequilibrium across three populations indicating possible association.

  15. Regulation of primary productivity rate in the equatorial Pacific

    SciTech Connect

    Barber, R.T. ); Chavez, F.P. )

    1991-12-01

    Analysis of the Chl-specific rate of primary productivity (P{sup B}) as a function of subsurface nutrient concentration at >300 equatorial stations provides an answer to the question: What processes regulate primary productivity rate in the high-nutrient, low-chlorophyll waters of the equatorial Pacific In the western Pacific where there is a gradient in 60-m (NO{sub 3}) from 0 to {approximately}12 {mu}M, the productivity rate is a linear function of nutrient concentration; in the eastern Pacific where the gradient is from 12 to 28 {mu}M, the productivity rate is independent of nutrient concentration and limited to {approximately}36 mg C(mg Chl){sup {minus}1} d{sup {minus}1}, or a mean euphotic zone C-specific growth rate ({mu}) of 0.47 d{sup {minus}1}. However, rates downstream of the Galapagos Islands are not limited; they are 46.4 mg C(mg Chl){sup {minus}1} d{sup {minus}1} and {mu} = 0.57 d{sup {minus}1}, very close to the predicted nutrient-regulated rates in the absence of other limitation. This pattern of rate regulation can be accounted for by a combination of eolian Fe, subsurface nutrients, and sedimentary Fe derived from the Galapagos platform. In the low-nutrient western Pacific the eolian supply of Fe is adequate to allow productivity rate to be set by subsurface nutrient concentration. In the nutrient-rich easter equatorial region eolian Fe is inadequate to support productivity rates proportional to the higher nutrient concentrations, so in this region eolian Fe is rate limiting. Around the Galapagos Islands productivity rates reach levels consistent with nutrient concentrations; sedimentary Fe from the Galapagos platform seems adequate to support increased nutrient-regulated productivity rates in this region.

  16. Concentrations and isotope ratios of carbon, nitrogen and sulfur in ocean-floor basalts

    USGS Publications Warehouse

    Sakai, H.; Marais, D.J.D.; Ueda, A.; Moore, J.G.

    1984-01-01

    Fresh submarine basalt glasses from Galapagos Ridge, FAMOUS area, Cayman Trough and Kilauea east rift contain 22 to 160 ppm carbon and 0.3 to 2.8 ppm nitrogen, respectively, as the sums of dissolved species and vesicle-filling gases (CO2 and N2). The large range of variation in carbon content is due to combined effect of depth-dependency of the solubility of carbon in basalt melt and varying extents of vapour loss during magma emplacement as well as in sample crushing. The isotopic ratios of indigenous carbon and nitrogen are in very narrow ranges,-6.2 ?? 0.2% relative to PDB and +0.2 ?? 0.6 %. relative to atmospheric nitrogen, respectively. In basalt samples from Juan de Fuca Ridge, however, isotopically light carbon (??13C = around -24%.) predominates over the indigenous carbon; no indigenous heavy carbon was found. Except for Galapagos Ridge samples, these ocean-floor basalts contain 670 to 1100 ppm sulfur, averaging 810 ppm, in the form of both sulfide and sulfate, whereas basalts from Galapagos Ridge are higher in both sulfur (1490 and 1570 ppm) and iron (11.08% total iron as FeO). The ??34S values average +0.3 ?? 0.5%. with average fractionation factor between sulfate and sulfide of +7.4 ?? 1.6%.. The sulfate/sulfide ratios tend to increase with increasing water content of basalt, probably because the oxygen fugacity increases with increasing water content in basalt melt. ?? 1984.

  17. MHC diversity and mate choice in the magellanic penguin, Spheniscus magellanicus.

    PubMed

    Knafler, Gabrielle J; Clark, J Alan; Boersma, P Dee; Bouzat, Juan L

    2012-01-01

    We estimated levels of diversity at the major histocompatibility complex (MHC) class II DRß1 gene in 50 breeding pairs of the Magellanic penguin and compared those to estimates from Humboldt and Galapagos penguins. We tested for positive selection and 2 conditions required for the evolution of MHC-based disassortative mating: 1) greater MHC diversity between breeding pairs compared to random mating, and 2) associations between MHC genotype and fitness. Cloning and sequencing of the DRß1 gene showed that Magellanic penguins had higher levels of genetic variation than Galapagos and Humboldt penguins. Sequence analysis revealed 45 alleles with 3.6% average proportion of nucleotide differences, nucleotide diversity of 0.030, and observed heterozygosity of 0.770. A gene phylogeny showed 9 allelic lineages with interspersed DRß1 sequences from Humboldt and Galapagos penguins, indicating ancestral polymorphisms. d (N)/d (S) ratios revealed evidence for positive selection. Analysis of breeding pairs showed no disassortative mating preferences. Significant MHC genotype/fitness associations in females suggest, however, that selection for pathogen resistance plays a more important role than mate choice in maintaining diversity at the MHC in the Magellanic penguin. The differential effect of MHC heterozygosity on fitness between the sexes is likely associated with the relative role of hatching and fledging rates as reliable indicators of overall fitness in males and females.

  18. The Origin of Spatial and Temporal Geochemical Variations in the Central American Volcanic Arc

    NASA Astrophysics Data System (ADS)

    Hoernle, K.; Heydolph, K.; Sadofsky, S.; Lissinna, B.; Hauff, F.; van den Bogaard, P.

    2006-12-01

    Variations in age and composition of the subduction input, slab dip, crustal thickness and crustal composition are likely to be the major controls on spatial and temporal variations along the Central American Volcanic Arc (CAVA). Our extensive new geochemical data set from volcanic rocks and olivine-hosted melt inclusions, combined with published data, shows systematic variations along two sections of the CAVA. Along the volcanic front (VF) from NW Nicaragua to Guatemala and across the arc from El Salvador to Honduras, variations in trace element (e.g. decrease in Ba/La and U/Th and increase in La/Yb) and isotopic composition (decrease in 143Nd/144Nd and increase in 206Pb/204Pb) suggest a decreasing role for a hydrous fluid component and an increasing role of a sediment melt component in the arc magmas to the NW along the VF and behind the VF. Since the age and composition of the subduction input are similar along this part of the arc, the decreasing slab dip angle, increase in crustal thickness and/or transition from mafic oceanic to evolved continental type basement are likely to control the observed geochemical variations. From NW Nicaragua to central Costa Rica, the most mafic lavas and melt inclusions show an increase in SiO2, La/Yb and 206Pb/204Pb and a decrease in FeO*, Ba/La, U/Th and 143Nd/144Nd, consistent with an increasing role of hydrous melts with Galapagos hotspot-type geochemical signatures contributing to the arc magmas to the SE. These geochemical variations correlate with an increasing overprinting of the incoming Cocos Plate by the Galapagos hotspot. There is a dramatic increase in Pb isotopic composition beginning at Arenal, which is coincident with the projection of the northern morphological boundary of the subducting Galapagos hotspot track. The fluid-mobile nature of Pb and the high Pb concentrations in the arc magmas indicate that the Pb isotopic composition (and the other geochemical variations) is primarily controlled by the subduction

  19. Telomeres and longevity: testing an evolutionary hypothesis.

    PubMed

    Haussmann, Mark F; Mauck, Robert A

    2008-01-01

    Identifying mechanisms that underlie variation in adult survivorship provide insight into the evolution of life history strategies and phenotypic variation in longevity. There is accumulating evidence that shortening telomeres, the protective caps at the ends of chromosomes, play an important role in individual variation in longevity. Given that telomeres generally shorten with age, it was surprising to find that in a population of a long-lived seabird, Leach's storm petrel, telomeres appear to lengthen with age. This unique finding suggested that the longest lived individuals are able to elongate telomeres, an interpretation we call the "elongation hypothesis." Alternatively, the "selection hypothesis" states that the longest lived individuals start with the longest telomeres and variation in telomere length decreases with age due to the selective disappearance of individuals with short telomeres. In the same population in which evidence supporting both hypotheses was uncovered, we tested mutually exclusive predictions from the elongation and selection hypotheses by measuring telomere length with the telomere restriction fragment assay in hatchling and old, adult storm petrels. As previously found, adult birds had longer telomeres on average compared with hatchlings. We also found that 3 hatchlings had mean telomere lengths exceeding that of the most extreme old bird, old birds on average had longer initial telomere lengths than hatchlings, and the variance in mean telomere length was significantly greater for hatchlings than for old birds, all predicted by the selection hypothesis. Perhaps more surprisingly, the oldest adults also show little or no accumulation of short telomeres over time, a pattern unknown in other species. Long telomeres are thought to provide a buffer against cellular senescence and be generally indicative of genome stability and overall cell health. In storm petrels, because the progressive accumulation of short telomeres appears negligible

  20. Mercury concentrations in seabird tissues from Machias Seal Island, New Brunswick, Canada.

    PubMed

    Bond, Alexander L; Diamond, Antony W

    2009-07-01

    Mercury is a pervasive environmental contaminant, the anthropogenic portion of which is increasing globally, and in northeastern North America in particular. Seabirds frequently are used as indicators of the marine environment, including mercury contamination. We analysed paired samples for total mercury (Hg) concentrations in feathers and blood from adult and chick, albumen, and lipid-free yolk of seven seabirds breeding on Machias Seal Island, New Brunswick, Canada - Arctic Tern (Sterna paradisaea), Atlantic Puffin (Fratercula arctica), Common Eider (Somateria mollissima), Common Murre (Uria aalge), Common Tern (Sterna hirundo), Leach's Storm-petrel (Oceanodroma leucorhoa), and Razorbill (Alca torda). We also used stable-isotope ratios of carbon (delta(13)C), and nitrogen (delta(15)N) to evaluate the relationship between carbon source and trophic position and mercury. We found high Hg concentrations across tissue types in Leach's Storm-petrels, and Razorbills, with lower concentrations in other species, the lowest being in Common Eiders. Storm-petrels prey on mesopelagic fish that accumulate mercury, and Razorbills feed on larger, older fish that bioaccumulate heavy metals. Biomagnification of Hg, or the increase in Hg concentration with trophic position as measured by delta(15)N, was significant and greater in albumen than other tissues, whereas in other tissues, delta(15)N explained little of the overall variation in Hg concentration. Hg concentrations in egg components are higher on Machias Seal Island than other sites globally and in the Gulf of Maine region, but only for some species. Further detailed investigations are required to determine the cause of this trend. PMID:19419752

  1. Successful eradication of the European rabbit (Oryctolagus cuniculus) and house mouse (Mus musculus) from the island of Selvagem Grande (Macaronesian archipelago), in the Eastern Atlantic.

    PubMed

    Olivera, Paulo; Menezes, Dilia; Trout, Roger; Buckle, Alan; Geraldes, Pedro; Jesus, José

    2010-03-01

    The Portuguese island of Selvagem Grande (Great Salvage) in Macaronesia is an important seabird breeding station in the eastern Atlantic. Significant populations of Cory's shearwater Calonectris diomedea (Scopoli, 1769), Bulwer's petrel Bulweria bulweria (Jardine & Selby, 1828) and little shearwater Puffinus assimilis baroli (Bonaparte, 1857) are present, and white-faced storm-petrel Pelagodroma marina (Latham, 1790) and Madeiran storm-petrel Oceanodroma castro (Harcourt, 1851) populations are of global significance. Selvagem Grande also provides diverse habitats for an extensive flora, including 11 endemic species. The 270-ha island was also inhabited by two alien invasive mammals: the European rabbit Oryctolagus cuniculus (Linnaeus, 1758) and the house mouse Mus musculus (Linnaeus, 1758). Both are known to have had adverse impacts on breeding seabirds and island vegetation. In 2002, the Natural Park of Madeira conducted a program using brodifacoum bait formulations aimed at rabbit and mouse eradication. Approximately 17 000 individual baiting points were established on a 12.5 × 12.5 m grid. Baits were also applied by hand "seeding" on steep slopes and cliffs where bait stations could not be placed. Rabbits were removed after a month. However, mice persisted for considerably longer and strategic bait applications against them continued for a further six months. Subsequent assessments by trapping, bait takes and systematic observation of signs over three years, has confirmed the removal of both alien invasive species. This paper presents information on these operations, on measures adopted to mitigate adverse impacts of the eradication program on important vertebrate non-target species, including Berthelot's pipit Anthus berthelotii Bolle, 1862 and a species of gecko Tarentola bischoffi Joger, 1984 and on the initial response of the island's ecosystem to the eradication of rabbits and mice. PMID:21392324

  2. Mercury in feathers from Chilean birds: Influence of location, feeding strategy, and taxonomic affiliation

    USGS Publications Warehouse

    Ochoa-Acua, H.; Sepulveda, M.S.; Gross, T.S.

    2002-01-01

    This study reports baseline concentrations of mercury (Hg) in feathers from different species of birds sampled at various locations off the Chilean coast (Southeastern Pacific). Hg concentrations were evaluated in relation to geographic location, taxonomic affiliation, and feeding strategies. Between January and March of 1995, we collected mature contour feathers from 116 birds belonging to 22 species, mostly seabirds. Birds were collected from 10 different locations (26??09???S, 70??40???W to 54??56???S, 67??37???W). Feather Hg concentrations ranged from 0.11 to 13 ??gg-1 dry weight. We found differences in feather Hg concentrations across taxonomic groups, with highest concentrations in petrels, shearwaters, and albatrosses (Procellaridae), followed by boobies (Sulidae), gulls, terns, skuas (Laridae) and cormorants (Phalacrocoracidae). Ibises and oystercatchers (Threskiornithidae and Charadriidae) had intermediate values, whereas ducks and geese (Anatidae) contained the least amount of Hg. Oceanic species preying on mesopelagic fish (the Procellariformes albatrosses, petrels, and fulmars) had over twice as much Hg (overall average of 3.9 ??gg-1) when compared to the rest of the species sampled (overall average of 1.5 ??gg-1). We did not find higher Hg concentrations in birds inhabiting the more heavily industrialized and urbanized areas of the country (central and northern regions), but in birds inhabiting the remote Juan Ferna??ndez Archipelago. This is not surprising, since all the Procellariformes (the group with highest Hg values in this study) were collected from these islands. Except for Hg in Kermadec petrels (mean of 12 ??gg-1), the range of Hg values reported here (0.11-7.3 ??gg-1) fell below those known to cause adverse health and reproductive effects in birds. ?? 2002 Elsevier Science Ltd. All rights reserved.

  3. Mercury in feathers from Chilean birds: Influence of location, feeding strategy and taxonomic affiliation

    USGS Publications Warehouse

    Ochoa-Acuna, H.G.; Sepulveda, M.S.; Gross, T.S.

    2002-01-01

    This study reports baseline concentrations of mercury (Hg) in feathers from different species of birds sampled at various locations off the Chilean coast (Southeastern Pacific). Hg concentrations were evaluated in relation to geographic location, taxonomic affiliation, and feeding strategies. Between January and March of 1995, we collected mature contour feathers from 116 birds belonging to 22 species, mostly seabirds. Birds were collected from 10 different locations (26?09'S, 70?40'W to 54?56'S, 67?37'W). Feather Hg concentrations ranged from 0.11 to 13 ?g g-1 dry weight. We found differences in feather Hg concentrations across taxonomic groups, with highest concentrations in petrels, shearwaters, and albatrosses (Procellaridae), followed by boobies (Sulidae), gulls, terns, skuas (Laridae) and cormorants (Phalacrocoracidae). Ibises and oystercatchers (Threskiornithidae and Charadriidae) had intermediate values, whereas ducks and geese (Anatidae) contained the least amount of Hg. Oceanic species preying on mesopelagic fish (the Procellariformes albatrosses, petrels, and fulmars) had over twice as much Hg (overall average of 3.9 ?g g-1) when compared to the rest of the species sampled (overall average of 1.5 ?g g-1). We did not find higher Hg concentrations in birds inhabiting the more heavily industrialized and urbanized areas of the country (central and northern regions), but in birds inhabiting the remote Juan Fernandez Archipelago. This is not surprising, since all the Procellariformes (the group with highest Hg values in this study) were collected from these islands. Except for Hg in Kermadec petrels (mean of 12 ?g g-1), the range of Hg values reported here (0.11-7.3 ?g g-1) fell below those known to cause adverse health and reproductive effects in birds.

  4. Ixodes philipi: redescription of female and first description of male, with records from streaked shearwater in Japan (Acarina: Ixodidae).

    PubMed

    Takahashi, Mamoru; Misumi, Hitoko; Tsurumi, Miyako; Uchikawa, Kimito

    2005-05-01

    Ixodes philipi Keirans & Kohls, 1970 is so far known only from two female specimens taken from the streaked shearwater, Puffinus leucomelas (Temminck, 1835) [presently Calonectris leucomelas (Temminck, 1835)], or the madeiran storm-petrel, Oceanodroma castro (Harcourt, 1851), in Japan. We redescribe the female and describe the male of this species. We used nine adults (four males and five females) taken from the bodies of C. leucomelas and/or soil samples of their nest burrows in Japan, indicating that C. leucomelas is the main natural host bird of I. philipi. PMID:15962766

  5. Diurnal variation of mesospheric ozone

    NASA Astrophysics Data System (ADS)

    Vaughan, G.

    1982-03-01

    Four Petrel rockets were flown from South Uist on October 2, 1979, to investigate the ozone concentration variation predicted by photochemical models between day and night in the mesosphere by means of interference filters that defined an approximately 10 nm bandwidth. The first two rockets contained photometers with wavebands centered at 265 and 290 nm, while the last two employed a single waveband at 265 nm. Results show significant diurnal variation above 54 km, which exceeds a factor of 2 above 65 km and reaches a factor of 10 between night and sunrise at 90 km.

  6. ETON 1 - A data base pertinent to the study of energy transfer in the oxygen nightglow

    NASA Astrophysics Data System (ADS)

    Greer, R. G. H.; Murtagh, D. P.; McDade, I. C.; Dickinson, P. H. G.; Thomas, L.

    1986-09-01

    A comprehensive group of experiments, assembled and flown on a series of Petrel rockets in March 1982 for the primary purpose of investigating the extent to which energy transfer is important in the excitation of the oxgen nightglow, is briefly described. Aspects of the data reduction methods are summarised and the bulk of the processed data is presented in profile and tabular form as a base for modelling and analyses in papers to follow and in evidence of the quality and success of this memorable international collaborative campaign.

  7. Sounding rocket attitude determination from on board magnetometer and telemetry signal polarisation data

    NASA Astrophysics Data System (ADS)

    Murtagh, D. P.; Greer, R. G. H.; McDade, I. C.

    1983-06-01

    The attitude of Petrel sounding rockets was determined from on-board magnetometer information and p band telemetry signal strength data from a polarized ground station antenna. Sky background information from the photometric payloads was compared to backgrounds reconstructed from satellite maps to assess the accuracy of the method. The result is consistant with other information available (sky background modulation) within the experimental constraints such as magnetometer calibration and light tables, and does not require extra hardware on the rocket. Accuracy can be improved by machine computation of the phase angles and a closer analysis of the whole flight especially around turnover on reentry.

  8. The 2.2 Hz oscillations in auroral electrons

    NASA Astrophysics Data System (ADS)

    Lepine, D. R.; Hall, D. S.; Bryant, D. A.; Johnstone, A. D.; Christiansen, P. J.; Gough, M. P.

    1980-06-01

    A Petrel rocket was launched from Kiruna on 25 January 1979 to compare electron intensities measured at auroral altitudes with related parameters measured at geostationary altitude by the satellite GEOS 2. A sequence of quasi-periodic oscillations in electron intensities were investigated, which appear to originate in the equatorial region, probably in the neighborhood of GEOS 2 was investigated. A similar frequency oscillation in the intensity of 500-Hz VLF emissions was observed at about the same time by the S300 wave experiment located on the satellite.

  9. Australia`s southeastern Bonaparte basin has plenty of potential

    SciTech Connect

    Miyazaki, S.

    1997-04-21

    Situated in the Timor Sea and Joseph Bonaparte Gulf regions, the Bonaparte basin is one of the Phanerozoic basins of what is now called the North West Shelf of Australia. This basin consists of a number of Paleozoic and Mesozoic synclines and horsts. Drilling success rate for this basin is one of the highest in Australia in the last 5 years. New opportunities are available in the southeastern Bonaparte basin, where seven vacant tracts have just been released for application for exploration permits. The paper discusses the regional geology, previous exploration activities, and potentials of the southern Petrel sub-basin and Darwin shelf.

  10. History of British Space Science

    NASA Astrophysics Data System (ADS)

    Massie, Harrie; Robins, M. O.

    2009-12-01

    1. The scientific background; 2. The technical background; 3. The initiation of the Skylark rocket programme; 4. Post IGY developments; 5. The Ariel programme; 6. The European Space Research Organisation; 7. Commonwealth co-operation in space research; 8. Smaller rockets for scientific purposes - Skua and Petrel; 9. Attitude controlled Skylark rockets; 10. The Trend Committee and the Science Research Council; 11. The transformation of ESRO into ESA; 12. The Space Science Committee for Europe; 13. Scientific studies by British space scientists I; 14. Scientific studies by British space scientists II; 15. The contribution from British space scientists to astronomy; 16. Concluding remarks; Appendices; Annexes.

  11. Prediction of weather operating windows for offshore drilling vessels

    SciTech Connect

    Hayes, J.G.; Hirt, M.S.; McGillivray, D.G.; Nicholls, B.; Waymouth, R.

    1983-05-01

    A management 'tool' for predicting Weather Operating Windows for offshore drilling operations has been developed and tested for the dynamic positioning drillship PETREL. It is shown that two measures are required in making such an assessment: the persistence of vessel heave response as it affects drilling operations and the probable downtimes with respect to each drilling operation throughout the year for the geographical location of interest. The study includes a detailed meteorological/oceanographic investigation of the physical environmental conditions for some Canadian east coast marine areas.

  12. The shark assemblage at French Frigate Shoals atoll, Hawai'i: species composition, abundance and habitat use.

    PubMed

    Dale, Jonathan J; Stankus, Austin M; Burns, Michael S; Meyer, Carl G

    2011-01-01

    Empirical data on the abundance and habitat preferences of coral reef top predators are needed to evaluate their ecological impacts and guide management decisions. We used longline surveys to quantify the shark assemblage at French Frigate Shoals (FFS) atoll from May to August 2009. Fishing effort consisted of 189 longline sets totaling 6,862 hook hours of soak time. A total of 221 sharks from 7 species were captured, among which Galapagos (Carcharhinus galapagensis, 36.2%), gray reef (Carcharhinus amblyrhynchos, 25.8%) and tiger (Galeocerdo cuvier, 20.4%) sharks were numerically dominant. A lack of blacktip reef sharks (Carcharhinus melanopterus) distinguished the FFS shark assemblage from those at many other atolls in the Indo-Pacific. Compared to prior underwater visual survey estimates, longline methods more accurately represented species abundance and composition for the majority of shark species. Sharks were significantly less abundant in the shallow lagoon than adjacent habitats. Recaptures of Galapagos sharks provided the first empirical estimate of population size for any Galapagos shark population. The overall recapture rate was 5.4%. Multiple closed population models were evaluated, with Chao M(h) ranking best in model performance and yielding a population estimate of 668 sharks with 95% confidence intervals ranging from 289-1720. Low shark abundance in the shallow lagoon habitats suggests removal of a small number of sharks from the immediate vicinity of lagoonal islets may reduce short-term predation on endangered monk seal (Monachus schauinslandi) pups, but considerable fishing effort would be required to catch even a small number of sharks. Additional data on long-term movements and habitat use of sharks at FFS are required to better assess the likely ecological impacts of shark culling. PMID:21347321

  13. The Shark Assemblage at French Frigate Shoals Atoll, Hawai‘i: Species Composition, Abundance and Habitat Use

    PubMed Central

    Dale, Jonathan J.; Stankus, Austin M.; Burns, Michael S.; Meyer, Carl G.

    2011-01-01

    Empirical data on the abundance and habitat preferences of coral reef top predators are needed to evaluate their ecological impacts and guide management decisions. We used longline surveys to quantify the shark assemblage at French Frigate Shoals (FFS) atoll from May to August 2009. Fishing effort consisted of 189 longline sets totaling 6,862 hook hours of soak time. A total of 221 sharks from 7 species were captured, among which Galapagos (Carcharhinus galapagensis, 36.2%), gray reef (Carcharhinus amblyrhynchos, 25.8%) and tiger (Galeocerdo cuvier, 20.4%) sharks were numerically dominant. A lack of blacktip reef sharks (Carcharhinus melanopterus) distinguished the FFS shark assemblage from those at many other atolls in the Indo-Pacific. Compared to prior underwater visual survey estimates, longline methods more accurately represented species abundance and composition for the majority of shark species. Sharks were significantly less abundant in the shallow lagoon than adjacent habitats. Recaptures of Galapagos sharks provided the first empirical estimate of population size for any Galapagos shark population. The overall recapture rate was 5.4%. Multiple closed population models were evaluated, with Chao Mh ranking best in model performance and yielding a population estimate of 668 sharks with 95% confidence intervals ranging from 289–1720. Low shark abundance in the shallow lagoon habitats suggests removal of a small number of sharks from the immediate vicinity of lagoonal islets may reduce short-term predation on endangered monk seal (Monachus schauinslandi) pups, but considerable fishing effort would be required to catch even a small number of sharks. Additional data on long-term movements and habitat use of sharks at FFS are required to better assess the likely ecological impacts of shark culling. PMID:21347321

  14. Ozone in the Pacific Troposphere from Ozonesonde Observations

    NASA Technical Reports Server (NTRS)

    Oltmans, S. J.; Johnson, B. J.; Harris, J. M.; Voemel, H.; Koshy, K.; Simon, P.; Bendura, R.; Thompson, A. M.; Logan, J. A.; Hasebe, F.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Ozone vertical profile measurements obtained from ozonesondes flown at Fiji, Samoa, Tahiti and the Galapagos are used to characterize ozone in the troposphere over the tropical Pacific. There is a significant seasonal variation at each of these sites. At sites in both the eastern and western Pacific, ozone is highest at almost all levels in the troposphere during the September-November season and lowest during, March-May. There is a relative maximum at all of the sites in the mid-troposphere during all seasons of the year (the largest amounts are usually found near the tropopause). This maximum is particularly pronounced during, the September-November season. On average, throughout the troposphere at all seasons, the Galapagos has larger ozone amounts than the western Pacific sites. A trajectory climatology is used to identify the major flow regimes that are associated with the characteristic ozone behavior at various altitudes and seasons. The enhanced ozone seen in the mid-troposphere during September-November is associated with flow from the continents. In the western Pacific this flow is usually from southern Africa (although 10-day trajectories do not always reach the continent), but also may come from Australia and Indonesia. In the Galapagos the ozone peak in the mid-troposphere is seen in flow from the South American continent and particularly from northern Brazil. The time of year and flow characteristics associated with the ozone mixing ratio peaks seen in both the western and eastern Pacific suggest that these enhanced ozone values result from biomass burning. In the upper troposphere low ozone amounts are seen with flow that originates in the convective western Pacific.

  15. The shark assemblage at French Frigate Shoals atoll, Hawai'i: species composition, abundance and habitat use.

    PubMed

    Dale, Jonathan J; Stankus, Austin M; Burns, Michael S; Meyer, Carl G

    2011-02-10

    Empirical data on the abundance and habitat preferences of coral reef top predators are needed to evaluate their ecological impacts and guide management decisions. We used longline surveys to quantify the shark assemblage at French Frigate Shoals (FFS) atoll from May to August 2009. Fishing effort consisted of 189 longline sets totaling 6,862 hook hours of soak time. A total of 221 sharks from 7 species were captured, among which Galapagos (Carcharhinus galapagensis, 36.2%), gray reef (Carcharhinus amblyrhynchos, 25.8%) and tiger (Galeocerdo cuvier, 20.4%) sharks were numerically dominant. A lack of blacktip reef sharks (Carcharhinus melanopterus) distinguished the FFS shark assemblage from those at many other atolls in the Indo-Pacific. Compared to prior underwater visual survey estimates, longline methods more accurately represented species abundance and composition for the majority of shark species. Sharks were significantly less abundant in the shallow lagoon than adjacent habitats. Recaptures of Galapagos sharks provided the first empirical estimate of population size for any Galapagos shark population. The overall recapture rate was 5.4%. Multiple closed population models were evaluated, with Chao M(h) ranking best in model performance and yielding a population estimate of 668 sharks with 95% confidence intervals ranging from 289-1720. Low shark abundance in the shallow lagoon habitats suggests removal of a small number of sharks from the immediate vicinity of lagoonal islets may reduce short-term predation on endangered monk seal (Monachus schauinslandi) pups, but considerable fishing effort would be required to catch even a small number of sharks. Additional data on long-term movements and habitat use of sharks at FFS are required to better assess the likely ecological impacts of shark culling.

  16. Moving polewards in winter: a recent change in the migratory strategy of a pelagic seabird?

    PubMed Central

    2010-01-01

    Background During the non-breeding period, many birds migrate to milder areas, found closer to the equator than their breeding sites. Opposite movements are very rare. In the Southern Ocean, the abundance of 13C declines markedly with more southern latitude, providing a characteristic 13C isoscape. This can be used as a tracer for the movement of seabirds between breeding and inter-breeding areas, by comparing stable isotope ratios of feathers grown at different times of the year. Results We studied seasonal movements of Thin-billed prions (Aves, Procellariiformes), breeding at the Subantarctic Falkland/Malvinas Islands, compared with those of Wilson's storm-petrels breeding in the Antarctic South Shetland Islands. The two species showed opposite migratory movements. While Wilson's storm-petrels moved to warmer waters north of the Drake Passage in winter, Thin-billed prions showed a reversed movement towards more polar waters. Carbon stable isotope ratios in recent and historical feathers indicated that poleward winter movements of Thin-billed prions were less common historically (45% in 1913-1915), and have only recently become dominant (92% in 2003-2005), apparently in response to warming sea temperatures. Conclusions This study shows that pelagic seabirds can rapidly change migration strategies within populations, including migration towards more poleward waters in winter. PMID:20482826

  17. Penguins are attracted to dimethyl sulphide at sea.

    PubMed

    Wright, Kyran L B; Pichegru, Lorien; Ryan, Peter G

    2011-08-01

    Breeding Spheniscus penguins are central place foragers that feed primarily on schooling pelagic fish. They are visual hunters, but it is unclear how they locate prey patches on a coarse scale. Many petrels and storm petrels (Procellariiformes), the penguins' closest relatives, use olfactory cues to locate prey concentrations at sea, but this has not been demonstrated for penguins. Procellariiforms are attracted to a variety of olfactory cues, including dimethyl sulphide (DMS), an organosulphur compound released when phytoplankton is grazed, as well as fish odorants such as cod liver oil. A recent study found that African penguins Spheniscus demersus react to DMS on land. We confirm this result and show that African penguins are also attracted by DMS at sea. DMS-scented oil slicks attracted 2-3 times more penguins than control slicks, whereas penguins showed no response to slicks containing cod liver oil. The number of penguins attracted to DMS increased for at least 30 min, suggesting penguins could travel up to 2 km to reach scent cues. Repeats of land-based trials confirmed previous results showing DMS sensitivity of penguins on land. Our results also support the hypothesis that African penguins use DMS as an olfactory cue to locate prey patches at sea from a distance, which is particularly important given their slow commuting speed relative to that of flying seabirds.

  18. Penguins are attracted to dimethyl sulphide at sea.

    PubMed

    Wright, Kyran L B; Pichegru, Lorien; Ryan, Peter G

    2011-08-01

    Breeding Spheniscus penguins are central place foragers that feed primarily on schooling pelagic fish. They are visual hunters, but it is unclear how they locate prey patches on a coarse scale. Many petrels and storm petrels (Procellariiformes), the penguins' closest relatives, use olfactory cues to locate prey concentrations at sea, but this has not been demonstrated for penguins. Procellariiforms are attracted to a variety of olfactory cues, including dimethyl sulphide (DMS), an organosulphur compound released when phytoplankton is grazed, as well as fish odorants such as cod liver oil. A recent study found that African penguins Spheniscus demersus react to DMS on land. We confirm this result and show that African penguins are also attracted by DMS at sea. DMS-scented oil slicks attracted 2-3 times more penguins than control slicks, whereas penguins showed no response to slicks containing cod liver oil. The number of penguins attracted to DMS increased for at least 30 min, suggesting penguins could travel up to 2 km to reach scent cues. Repeats of land-based trials confirmed previous results showing DMS sensitivity of penguins on land. Our results also support the hypothesis that African penguins use DMS as an olfactory cue to locate prey patches at sea from a distance, which is particularly important given their slow commuting speed relative to that of flying seabirds. PMID:21753043

  19. Contrasted patterns of age-specific reproduction in long-lived seabirds.

    PubMed

    Berman, M; Gaillard, J-M; Weimerskirch, H

    2009-01-22

    While the number of studies providing evidence of actuarial senescence is increasing, and covers a wide range of taxa, the process of reproductive senescence remains poorly understood. In fact, quite high reproductive output until the last years of life has been reported in several vertebrate species, so that whether or not reproductive senescence is widespread remains unknown. We compared age-specific changes of reproductive parameters between two closely related species of long-lived seabirds: the small-sized snow petrel Pagodroma nivea, and the medium-sized southern fulmar Fulmarus glacialoides. Both are sympatric in Antarctica. We used an exceptional dataset collected over more than 40 years to assess age-specific variations of both breeding probability and breeding success. We found contrasted age-specific reproductive patterns between the two species. Reproductive senescence clearly occurred from 21 years of age onwards in the southern fulmar, in both breeding probability and success, whereas we did not report any decline in the breeding success of the snow petrel, although a very late decrease in the proportion of breeders occurred at 34 years. Such a contrasted age-specific reproductive pattern was rather unexpected. Differences in life history including size or migratory behaviour are the most likely candidates to account for the difference we reported in reproductive senescence between these sympatric seabird species. PMID:18832060

  20. Geographic and trophic patterns of OCs in pelagic seabirds from the NE Atlantic and the Mediterranean: a multi-species/multi-locality approach.

    PubMed

    Roscales, Jose L; González-Solís, Jacob; Muñoz-Arnanz, Juan; Jiménez, Begoña

    2011-10-01

    Trophic ecology and geographic location are crucial factors explaining OC levels in marine vertebrates, but these factors are often difficult to disentangle. To examine their relative influence, we analyzed PCBs, DDTs and stable-nitrogen isotope signatures (δ15N) in the blood of 10 pelagic seabird species across 7 breeding localities from the northeast Atlantic and western Mediterranean. Large scale geographic patterns emerged due to the confined character and greater historical OC inputs in the Mediterranean compared to the Atlantic basin. Spatial patterns also emerged at the regional scale within the Atlantic basin, probably associated with long-range pollutant transport. Trophic ecology, however, was also a major factor explaining OC levels. We found clear and consistent OC differences among species regardless of the sampled locality. However, species δ15N and blood OC levels were not correlated within most breeding localities. Petrel species showed significantly greater OC burdens than most shearwater species but similar trophic positions, as indicated by their similar δ15N signatures. This pattern probably results from Petrel species feeding on mesopelagic fish and squid that migrate close to the sea surface at night, whereas shearwater species mainly feed on epipelagic diurnal prey. In sum, this study illustrates the lasting and unequal influence of past human activities such as PCB and DDT usage across different marine regions. In addition, our results suggest that multi-species designs are powerful tools to monitor geographic patterns of OCs and potentially useful to assess their vertical dynamics in the marine environment. PMID:21906778

  1. Distribution of 14 elements in tissues and organs of oceanic seabirds.

    PubMed

    Kim, E Y; Goto, R; Tanabe, S; Tanaka, H; Tatsukawa, R

    1998-11-01

    The concentrations of 14 trace elements (Li, V, Mn, Co, Cu, Zn, Se, Rb, Sr, Ag, Cd, Cs, Pb, and Hg) were determined in tissues and organs of three species and in the liver of 11 species of seabirds. Comparatively high concentrations of Li, Co, Sr, and V were found in the femur. Cd, Se, Cu, and Mn concentrations were relatively higher in the kidney than in other tissues and organs. Rb, Cs, and Pb concentrations were rather uniform among tissues. Concentrations of essential elements such as Mn, Cu, and Co were comparable among seabird species, except high Cu concentrations in northern giant petrel. Among nonessential elements, concentrations of Cd and Hg were variable according to seabird species. Pb levels were low in all the species. High Se levels (100 microg/g dry weight) were found in the liver of black-footed albatross and grey petrel. There were significant positive correlations between Se and Cd concentrations in three species and between Se and Hg in black-footed albatross, suggesting that Se has an antagonistic action on the toxic effects of Cd and Hg. Concentrations of Li, V, Ag, and Cs were usually low (less than 1 microg/g dry weight). PMID:9776782

  2. Marine foraging birds as bioindicators of mercury in the Gulf of Maine.

    PubMed

    Goodale, M Wing; Evers, David C; Mierzykowski, Steven E; Bond, Alexander L; Burgess, Neil M; Otorowski, Catherine I; Welch, Linda J; Hall, C Scott; Ellis, Julie C; Allen, R Bradford; Diamond, Anthony W; Kress, Stephen W; Taylor, Robert J

    2008-12-01

    From existing databases, we compiled and evaluated 604 total mercury (Hg) levels in the eggs and blood of 17 species of marine foraging birds from 35 Gulf of Maine islands to provide baseline data and to determine the best tissue, age class, and species for future biomonitoring. While mean Hg levels in most species did not exceed adverse effects thresholds, levels in some individual eggs did; for all species arithmetic mean egg Hg levels ranged from 0.04 to 0.62 (microg/g, wet weight). Piscivorous birds had higher Hg levels than invertivores. Leach's storm-petrel (Oceanodroma leucorhoa), razorbill (Alca torda), and black guillemot (Cepphus grylle) adult blood and egg Hg levels were higher than other species. Our results indicate that adult blood is preferable to chick blood for detecting long-term temporal trends because adult levels are higher and not confounded by metabolic effects. However, since we found that eggs and adult blood are comparable indicators of methylmercury bioavailability, we determined that eggs are the preferred tissue for long-term Hg monitoring because the relative ease in collecting eggs ensures consistent and robust datasets. We suggest specific sampling methods, and based on our results demonstrate that common eider (Somateria mollissima), Leach's storm-petrel, double-crested cormorant, and black guillemot are the most effective bioindicators of Hg of the Gulf of Maine. PMID:19277786

  3. Spatial heterogeneity of mesopredator release within an oceanic island system.

    PubMed

    Rayner, Matt J; Hauber, Mark E; Imber, Michael J; Stamp, Rosalie K; Clout, Mick N

    2007-12-26

    Predator-prey communities are ubiquitous in ecology, but introduced predators can drive native species to extinction within island systems, prompting the eradication of such exotics. Ecological theory predicts that elimination of top-introduced predators from islands can lead to the counterintuitive decline of native prey populations through the ecological release of smaller introduced species in a process termed "mesopredator release." We show, in accordance with mesopredator release theory and counter to conservation goals for a New Zealand island reserve, that initial eradication of cats on Little Barrier Island led to reduced breeding success of Cook's petrels, which also are vulnerable to predation by a mesopredator, the Pacific rat. The rat's impact on prey productivity varied with elevation within the island. Rat eradication was followed by a rise in petrel productivity, in support of both ecological theory and practical conservation management goals. It appears that interactions among introduced predators, native prey, and environmental gradients can drive counterintuitive and spatially heterogeneous responses to predator eradications from islands. Location-specific, ecosystem-level understanding is essential for predicting the outcomes of such restoration management techniques. PMID:18083843

  4. Temporal trends of perfluoroalkyl substances (PFAS) in eggs of coastal and offshore birds: Increasing PFAS levels associated with offshore bird species breeding on the Pacific coast of Canada and wintering near Asia.

    PubMed

    Miller, Aroha; Elliott, John E; Elliott, Kyle H; Lee, Sandi; Cyr, Francois

    2015-08-01

    Perfluoroalkyl substances (PFAS) such as perfluoroalkyl carboxylates (PFCAs) and perfluoroalkyl sulfonates (PFSAs) have become virtually ubiquitous throughout the environment, and, based on laboratory studies, have known toxicological consequences. Various national and international voluntary phase-outs and restrictions on these compounds have been implemented over the last 10 to 15 years. In the present study, we examine trends (1990/1991-2010/2011) in aquatic birds (ancient murrelet, Synthliboramphus antiquus [2009 only]; Leach's storm-petrels, Oceanodroma leucorhoa; rhinoceros auklets, Cerorhinca monocerata; double-crested cormorants, Phalacrocorax auritus; and great blue herons, Ardea herodias). The PFCA, PFSA, and stable isotope (δ(15) N and δ(13) C) data collected from these species from the Pacific coast of Canada, ranging over 20 to 30 years, were used to investigate temporal changes in PFAS coupled to dietary changes. Perfluorooctane sulfonic acid (PFOS), the dominant PFSA compound in all 4 species, increased and subsequently decreased in auklet and cormorant eggs in line with the manufacturing phase-out of PFOS and perfluorooctanoic acid (PFOA), but concentrations continuously increased in petrel eggs and remained largely unchanged in heron eggs. Dominant PFCA compounds varied between the offshore and coastal species, with increases seen in the offshore species and little or variable changes seen in the coastal species. Little temporal change was seen in stable isotope values, indicating that diet alone is not driving observed PFAS concentrations. PMID:25989421

  5. A Theoretical Analysis of Sea-anchor Soaring.

    PubMed

    Sugimoto

    1998-06-01

    This study presents a concise mathematical model that accounts for sea-anchor soaring, a special flight technique used by sea birds, in particular storm petrels. Conventional wing theory is used to reveal the mechanics of sea-anchor soaring. The feasibility and existence of an equilibrium are summarized by formulae giving the wind velocity criteria. The stability of the equilibrium is also revealed: among two possible equilibria, the equilibrium at the very low velocity to water is shown to be stable. Numerical examples show the following: sea-anchor soaring is almost always stable; Wilson's storm petrel can soar at 0.256 ms-1 in wind with 4.79 ms-1 under the best conditions. Larger sea-birds like albatrosses need gusty winds to soar, but such strong winds make the sea choppy and hence prevent soaring. Foot-web size regulates the size of a bird utilizing sea-anchor soaring at low velocities to water.Copyright 1998 Academic Press Limited PMID:9735255

  6. Back home at night or out until morning? Nycthemeral variations in homing of anosmic Cory's shearwaters in a diurnal colony.

    PubMed

    Dell'Ariccia, Gaia; Bonadonna, Francesco

    2013-04-15

    Olfactory cues have been shown to be important to homing petrels at night, but apparently those procellariiform species that also come back to the colony during the day are not impaired by smell deprivation. However, the nycthemeral distribution of homing, i.e. whether displaced birds released at night return to their burrow by night or during daylight, has never been investigated. To explore this question, we studied the homing behaviour of Cory's shearwater (Calonectris borealis) in the only known population where these birds are active at the colony both during the day and at night. Here, we compared the nocturnal versus diurnal homing schedule of birds treated with zinc sulphate (to induce a reversible but complete anosmia) with that of controls. Our results show that anosmic shearwaters were unable to home in the dark and were constrained to wait for the daylight to find their burrow again. Our results confirm that olfaction is the basic sensory input for homing by night even in a petrel species that is diurnally active at the colony. PMID:23307801

  7. Distribution of marine birds on the mid- and North-Atlantic US outer continental shelf. Technical progress report, January 1978-July 1980

    SciTech Connect

    Powers, K.D.; Pittman, G.L.; Fitch, S.J.

    1980-09-01

    The species composition, distribution, and abundance of marine birds on continental shelf waters from Cape Hatteras to the Bay of Fundy were examined using ships-of-opportunity. Northern Fulmar, Cory's Shearwater, Greater Shearwater, Sooty Shearwater, Wilson's Storm-Petrel, Gannet, Red Phalarope, Great Black-backed Gull, Herring Gull, and Black-legged Kittiwake were the most abundant and common species. These species were ecologically dominant within the bird community in numbers and biomass. Georges Bank and Gulf of Marine regions generally had greatest estimates of standing stock and biomass; whereas, in the Middle Atlantic region these estimates were consistently lowest. Species diversity throughout the study area was greatest in spring and least in fall. Oceanic fronts at the continental shelf break and at Nantucket Shoals influenced the distribution of Wilson's Storm-Petrels and Red Phalaropes. Fishing activities were particularly important to Larus gull distribution. Fishes, squids, and crustaceans were the most important groups of prey items in diets of nine bird species. An oiled bird or pollution index was developed. According to the index, frequency of oiled birds was greatest in winter and spring, and gulls made up the majority of species with oiled plumages.

  8. Spatial heterogeneity of mesopredator release within an oceanic island system

    PubMed Central

    Rayner, Matt J.; Hauber, Mark E.; Imber, Michael J.; Stamp, Rosalie K.; Clout, Mick N.

    2007-01-01

    Predator–prey communities are ubiquitous in ecology, but introduced predators can drive native species to extinction within island systems, prompting the eradication of such exotics. Ecological theory predicts that elimination of top-introduced predators from islands can lead to the counterintuitive decline of native prey populations through the ecological release of smaller introduced species in a process termed “mesopredator release.” We show, in accordance with mesopredator release theory and counter to conservation goals for a New Zealand island reserve, that initial eradication of cats on Little Barrier Island led to reduced breeding success of Cook's petrels, which also are vulnerable to predation by a mesopredator, the Pacific rat. The rat's impact on prey productivity varied with elevation within the island. Rat eradication was followed by a rise in petrel productivity, in support of both ecological theory and practical conservation management goals. It appears that interactions among introduced predators, native prey, and environmental gradients can drive counterintuitive and spatially heterogeneous responses to predator eradications from islands. Location-specific, ecosystem-level understanding is essential for predicting the outcomes of such restoration management techniques. PMID:18083843

  9. Molecules vs. morphology in avian evolution: the case of the "pelecaniform" birds.

    PubMed

    Hedges, S B; Sibley, C G

    1994-10-11

    The traditional avian Order Pelecaniformes is composed of birds with all four toes connected by a web. This "totipalmate" condition is found in ca. 66 living species: 8 pelicans (Pelecanus), 9 boobies and gannets (Sula, Papasula, Morus), ca. 37 cormorants (Phalacrocorax), 4 anhingas or darters (Anhinga), 5 frigatebirds (Fregata), and 3 tropicbirds (Phaethon). Several additional characters are shared by these genera, and their monophyly has been assumed since the beginning of modern zoological nomenclature. Most ornithologists classify these genera as an order, although tropicbirds have been viewed as related to terns, and frigatebirds as relatives of the petrels and albatrosses. DNA.DNA hybridization data indicated that the pelicans are most closely related to the Shoebill (Balaeniceps rex), a stork-like bird that lives in the swamps of central Africa; the boobies, gannets, cormorants, and anhingas form a closely related cluster; the tropicbirds are not closely related to the other taxa; and the frigatebirds are closest to the penguins, loons, petrels, shearwaters, and albatrosses (Procellarioidea). Most of these results are corroborated by DNA sequences of the 12S and 16S rRNA mitochondrial genes, and they provide another example of incongruence between classifications derived from morphological versus genetic traits.

  10. Molecules vs. morphology in avian evolution: the case of the "pelecaniform" birds.

    PubMed Central

    Hedges, S B; Sibley, C G

    1994-01-01

    The traditional avian Order Pelecaniformes is composed of birds with all four toes connected by a web. This "totipalmate" condition is found in ca. 66 living species: 8 pelicans (Pelecanus), 9 boobies and gannets (Sula, Papasula, Morus), ca. 37 cormorants (Phalacrocorax), 4 anhingas or darters (Anhinga), 5 frigatebirds (Fregata), and 3 tropicbirds (Phaethon). Several additional characters are shared by these genera, and their monophyly has been assumed since the beginning of modern zoological nomenclature. Most ornithologists classify these genera as an order, although tropicbirds have been viewed as related to terns, and frigatebirds as relatives of the petrels and albatrosses. DNA.DNA hybridization data indicated that the pelicans are most closely related to the Shoebill (Balaeniceps rex), a stork-like bird that lives in the swamps of central Africa; the boobies, gannets, cormorants, and anhingas form a closely related cluster; the tropicbirds are not closely related to the other taxa; and the frigatebirds are closest to the penguins, loons, petrels, shearwaters, and albatrosses (Procellarioidea). Most of these results are corroborated by DNA sequences of the 12S and 16S rRNA mitochondrial genes, and they provide another example of incongruence between classifications derived from morphological versus genetic traits. Images PMID:7937906

  11. Temporal trends of perfluoroalkyl substances (PFAS) in eggs of coastal and offshore birds: Increasing PFAS levels associated with offshore bird species breeding on the Pacific coast of Canada and wintering near Asia.

    PubMed

    Miller, Aroha; Elliott, John E; Elliott, Kyle H; Lee, Sandi; Cyr, Francois

    2015-08-01

    Perfluoroalkyl substances (PFAS) such as perfluoroalkyl carboxylates (PFCAs) and perfluoroalkyl sulfonates (PFSAs) have become virtually ubiquitous throughout the environment, and, based on laboratory studies, have known toxicological consequences. Various national and international voluntary phase-outs and restrictions on these compounds have been implemented over the last 10 to 15 years. In the present study, we examine trends (1990/1991-2010/2011) in aquatic birds (ancient murrelet, Synthliboramphus antiquus [2009 only]; Leach's storm-petrels, Oceanodroma leucorhoa; rhinoceros auklets, Cerorhinca monocerata; double-crested cormorants, Phalacrocorax auritus; and great blue herons, Ardea herodias). The PFCA, PFSA, and stable isotope (δ(15) N and δ(13) C) data collected from these species from the Pacific coast of Canada, ranging over 20 to 30 years, were used to investigate temporal changes in PFAS coupled to dietary changes. Perfluorooctane sulfonic acid (PFOS), the dominant PFSA compound in all 4 species, increased and subsequently decreased in auklet and cormorant eggs in line with the manufacturing phase-out of PFOS and perfluorooctanoic acid (PFOA), but concentrations continuously increased in petrel eggs and remained largely unchanged in heron eggs. Dominant PFCA compounds varied between the offshore and coastal species, with increases seen in the offshore species and little or variable changes seen in the coastal species. Little temporal change was seen in stable isotope values, indicating that diet alone is not driving observed PFAS concentrations.

  12. Major histocompatibility complex class II compatibility, but not class I, predicts mate choice in a bird with highly developed olfaction.

    PubMed

    Strandh, Maria; Westerdahl, Helena; Pontarp, Mikael; Canbäck, Björn; Dubois, Marie-Pierre; Miquel, Christian; Taberlet, Pierre; Bonadonna, Francesco

    2012-11-01

    Mate choice for major histocompatibility complex (MHC) compatibility has been found in several taxa, although rarely in birds. MHC is a crucial component in adaptive immunity and by choosing an MHC-dissimilar partner, heterozygosity and potentially broad pathogen resistance is maximized in the offspring. The MHC genotype influences odour cues and preferences in mammals and fish and hence olfactory-based mate choice can occur. We tested whether blue petrels, Halobaena caerulea, choose partners based on MHC compatibility. This bird is long-lived, monogamous and can discriminate between individual odours using olfaction, which makes it exceptionally well suited for this analysis. We screened MHC class I and II B alleles in blue petrels using 454-pyrosequencing and quantified the phylogenetic, functional and allele-sharing similarity between individuals. Partners were functionally more dissimilar at the MHC class II B loci than expected from random mating (p = 0.033), whereas there was no such difference at the MHC class I loci. Phylogenetic and non-sequence-based MHC allele-sharing measures detected no MHC dissimilarity between partners for either MHC class I or II B. Our study provides evidence of mate choice for MHC compatibility in a bird with a high dependency on odour cues, suggesting that MHC odour-mediated mate choice occurs in birds.

  13. Thirty-eighth supplement to the American Ornithologists' Union Check-List of North American Birds

    USGS Publications Warehouse

    Monroe, Burt L.; Banks, Richard C.; Fitzpatrick, John W.; Howell, Thomas R.; Johnson, Ned K.; Ouellet, Henri; Remsen, J.V.; Storer, Robert W.

    1991-01-01

    This fourth supplement after the 6th edition (1983) of the AOU "Check-list of North American Birds" consists of changes adopted by the Committee on Classification and Nomenclature between 1 March 1989 and 1 March 1991. The changes fall into eight categories: (1) five species (Ixobrychus sinensis, Porphyrula flavirostris, Sterna bergii, Streptopelia orientalis, and Ficedula narcissina) are added to the main list because of new distributional information; (2) six species (Pterodroma cervicalis, Ortalis wagleri, Lophornis brachylopha, Corvus sinaloae, Cinclocerthia gutturalis, and Loxops caeruleirostris) are added to the list because of the splitting of species previously in the list; (3) one extinct species (Dysmorodrepanis munroi) is added to the list because of re-identification of the unique type; (4) one scientific name (Speotyto cunicularia) is changed because of generic splitting; (5) one scientific name (Phalacrocorax brasilianus) is changed for nomenclature reasons, accompanied by a change in English name; (6) the spelling of one scientific name (Neocrex colombianus) is corrected; (7) to other English names are changed or corrected; and (8) one sequencing change is made. No new distributional information is included except as noted above (i.e. minor changes of distribution of distributional records within North America are not included). The twelve additions bring the number of species recognized as occurring within the Check-list area (main list) to 1957.

  14. Helium and neon isotopes in phenocrysts from Samoan lavas: Evidence for heterogeneity in the terrestrial high 3He/ 4He mantle

    NASA Astrophysics Data System (ADS)

    Jackson, Matthew G.; Kurz, Mark D.; Hart, Stanley R.

    2009-10-01

    We report the first neon isotope measurements on phenocrysts from subaerial and submarine Samoan lavas. These new data complement existing Ne-isotope data from Samoan peridotite xenoliths (Poreda, R.J., Farley, K.A.,1992. Rare gases in Samoan xenoliths. Earth Planet. Sci. Lett. 113, 689 129-144). Neon isotopes were measured in magmatic phenocrysts separated from nine shield-stage lavas from 5 Samoan volcanoes, including Ofu, Ta'u, Vailulu'u, Malumalu and Savai'i. Phenocrysts from subaerial Samoan lavas have higher 20Ne/ 22Ne than submarine phenocrysts, which may suggest different atmospheric contamination mechanisms for these two different eruptive environments. Olivine phenocrysts from a subaerial Ta'u lava exhibit the highest 20Ne/ 22Ne (11.33±0.08, 1σ) value in this study. Two subaerial Samoan samples from Ofu Island with high 3He/ 4He ratios (Ofu-04-06 and Ofu-04-03; 34 and 24 Ra [ratio to atmosphere], respectively) also have elevated 20Ne/ 22Ne ratios relative to air, and in a three-isotope neon plot the Ofu samples are indistinguishable from measurements made on high 3He/ 4He lavas from Hawaii, Iceland and Galapagos. The similarity of helium and neon isotopes in Ofu and Hawaii-Iceland-Galapagos is remarkable given the distinctions in 87Sr/ 86Sr (0.70458 for Ofu vs. 0.70329-0.70368 for Hawaii-Iceland-Galapagos) and 143Nd/ 144Nd (Ofu's 0.51283 vs. 0.51294-0.51297 for Hawaii-Iceland-Galapagos) in high 3He/ 4He lavas from these localities. Thus, the occurrence of similar helium and neon isotope compositions in lavas from these 4 hotspots does not appear to be linked to their variable Sr and Nd isotope compositions, and demonstrates a complex relationship between the isotopes of noble gases and the more refractory radiogenic isotopes. Additionally, we observe strongly nucleogenic neon isotopes in one the most isotopically-enriched ( 87Sr/ 86Sr > 0.718) Samoan lavas. This observation is consistent with the presence of recycled, continentally-derived marine

  15. New tool to manage coral reefs

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    The National Oceanic and Atmospheric Administration is making available a new tool for coral reef managers to monitor the cumulative thermal stress of several coral reefs around the world, including the Great Barrier Reef, and reefs by the Galapagos Islands, the agency announced on 25 February.The agency's "Degree Heating Weeks" product uses satellite-derived information to allow continuous monitoring of the extent and acuteness of thermal stress, which are key predictors of coral bleaching, and which contribute to coral reef degradation.

  16. Concentrations and isotope ratios of carbon, nitrogen and sulfur in ocean-floor basalts

    NASA Technical Reports Server (NTRS)

    Sakai, H.; Ueda, A.; Des Marais, D. J.; Moore, J. G.

    1984-01-01

    Ocean floor basalts studied from the Galapagos Ridge, FAMOUS area, Cayman Trough and Kilauea east rift contain 20-200 ppm carbon and 0.3-2.8 ppn nitrogen as sums of the vesicle-filling gases CO2 and N2 and dissolved species. The wide range of carbon contents found is due partly to the different extent of outgassing of vesicle-filling gases and partly to depth dependency of dissolved CO2 in the basalts. Sulfate commonly exists with sulfide in these basalts, and the sulfate/sulfide ratio increases with increasing water content, perhaps reflecting the higher oxidation potential in basalt melt of the higher water content.

  17. State of R&D in photonics-related fields in Japan's industry and academia: leading the green digital economy

    NASA Astrophysics Data System (ADS)

    Tatsuno, Kimio

    2010-06-01

    Photonics product statistics in Japan provided by OITDA is shown and analyzed from the aspect of three basic issues those the Japanese R & D state is facing. They are (1) off-shoring due to the deep integration in east Asia, (2) industry-academia collaboration and (3) global warming issue. The challengeable photonics R&D will come by aiming the volume zone market to get rid of the Galapagos problem and by opening innovation through the international collaboration. The connecting of the photonics products to the broadband systems are prospective to lead the "Green Digital Economy.

  18. Pb-isotopic Features of Primitive Rocks from Hess Deep: Distinguishing between EPR and Cocos-Nazca Mantle Source(s)

    NASA Astrophysics Data System (ADS)

    Jean, M. M.; Falloon, T.; Gillis, K. M.

    2014-12-01

    We have acquired high-precision Pb-isotopic signatures of primitive lithologies (basalts/gabbros) recovered from IODP Expedition 345.The Hess Deep Rift, located in the vicinity of the Galapagos triple junction (Cocos, Nazca, and Pacific), is viewed as one the best-studied tectonic windows into fast-spreading crust because a relatively young (<1.5 Ma) cross section of oceanic crust. This allows for (1) characterization of the mantle source(s) at Hess Deep, (2) insight into the extent of isotopic homogeneity or heterogeneity in the area, and (3) constrain the relative contributions from the intruding Cocos-Nazca spreading center. The observed Pb-isotopic variation at Hess Deep covers almost the entire range of EPR MORB (10°N to -5°S). Hess Deep samples range from 208Pb (37.3-38.25), 207Pb (15.47-15.58), 206Pb (17.69-18.91). These compositions suggest that this part of Hess Deep mantle is no more isotopically homogeneous than EPR mantle. Two distinct arrays are also observed: 208Pb-enriched (r2=0.985; n=30) and 208Pb-depleted (r2=0.988; n=6). The 208Pb/204Pb isotopes indicates that the Pb-source for some of the samples at Hess Deep had very low Th/U ratios, whereas other areas around the Galapagos microplate seem to have more "normal" ratios. These trends are less apparent when viewed with 207Pb-isotopes. Instead, the majority of basalts and gabbros follow the NHRL, however, at the depleted-end of this array a negative excursion to more enriched compositions is observed. This negative but linear trend could signify an alteration trend or mixing with an EMI-type mantle source, yet this mixing is not observed with 208Pb. This trend is also observed at Pito Deep, which has similar origins to Hess Deep (Barker et al., 2008; Pollack et al., 2009). The Galapagos region has been considered a testing ground for mixing of HIMU, Enriched Mantle, and Depleted Mantle reservoirs (e.g., Schilling et al., 2002). According to our data, however, an EPR-component must also be

  19. Avian evolution: from Darwin's finches to a new way of thinking about avian forebrain organization and behavioural capabilities.

    PubMed

    Reiner, Anton

    2009-02-23

    The study of birds, especially the Galapagos finches, was important to Darwin in the development of the theory of evolution by natural selection. Birds have also been at the centre of a recent reformulation in understanding cerebral evolution and the substrates for higher cognition. While it was once thought that birds possess a simple cerebrum and were thus limited to instinctive behaviours, it is now clear that birds possess a well-developed cerebrum that looks very different from the mammalian cerebrum but can support a cognitive ability that for some avian species rivals that in primates.

  20. Seismotectonics of mid-ocean ridge propagation in Hess Deep.

    PubMed

    Floyd, Jacqueline S; Tolstoy, Maya; Mutter, John C; Scholz, Christopher H

    2002-11-29

    Hydroacoustic data from the eastern equatorial Pacific reveal low-magnitude seismicity concentrated at the propagating tip of the Galapagos Rise in Hess Deep. The patterns of seismicity and faulting are similar to those observed in the process zone of laboratory-scale propagating tensile cracks. Because the fracture energy required for propagation scales with crack length and process zone size, it follows that ridges can propagate stably in the brittle crust without exceptional resisting forces as proposed by previous models based on linear elastic fracture mechanics.

  1. The 1998-2000 SHADOZ (Southern Hemisphere ADditional Ozonesondes) Tropical Ozone Climatology: Comparison with TOMS and Ground-Based Measurements

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Witte, Jacquelyn; McPeters, Richard D.; Oltmans, Samuel J.; Schmidlin, Francis J.; Logan, Jennifer A.; Fujiwara, Masatormo; Kirchhoff, Volker W. J. H.; Posny, Francoise; Coetzee, Gerhard J. R.; Bhartia, P. K. (Technical Monitor)

    2001-01-01

    A network of 10 southern hemisphere tropical and Subtropical stations, designated the Southern Hemisphere ADditional OZonesondes, (SHADOZ) project and established from operational sites, provided over 1000 ozone profiles during the period 1998-2000. Balloon-borne electrochemical concentration cell (ECC) ozonesondes, combined with standard radiosondes for pressure, temperature and relative humidity measurements, collected profiles in the troposphere and lower- to mid-stratosphere at: Ascension Island; Nairobi, Kenya; Irene, South Africa: Reunion Island, Watukosek Java; Fiji; Tahiti; American Samoa; San Cristobal, Galapagos; Natal, Brazil.

  2. Differences in foraging ecology align with genetically divergent ecotypes of a highly mobile marine top predator.

    PubMed

    Jeglinski, Jana W E; Wolf, Jochen B W; Werner, Christiane; Costa, Daniel P; Trillmich, Fritz

    2015-12-01

    Foraging differentiation within a species can contribute to restricted gene flow between ecologically different groups, promoting ecological speciation. Galapagos sea lions (Zalophus wollebaeki) show genetic and morphological divergence between the western and central archipelago, possibly as a result of an ecologically mediated contrast in the marine habitat. We use global positioning system (GPS) data, time-depth recordings (TDR), stable isotope and scat data to compare foraging habitat characteristics, diving behaviour and diet composition of Galapagos sea lions from a western and a central colony. We consider both juvenile and adult life stages to assess the potential role of ontogenetic shifts that can be crucial in shaping foraging behaviour and habitat choice for life. We found differences in foraging habitat use, foraging style and diet composition that aligned with genetic differentiation. These differences were consistent between juvenile and adult sea lions from the same colony, overriding age-specific behavioural differences. Our study contributes to an understanding of the complex interaction of ecological condition, plastic behavioural response and genetic make-up of interconnected populations. PMID:26307593

  3. Andean tectonics: Implications for Satellite Geodesy

    NASA Astrophysics Data System (ADS)

    Allenby, R. J.

    1984-09-01

    Current knowledge and theories of large scale Andean tectonics as they relate to site planning for the NASA Crustal Dynamics Program's proposed high precision geodetic measurements of relative motions between the Nazca and South American plates are summarized. The Nazca Plate and its eastern margin, the Peru-Chile Trench, is considered a prototype plate marked by rapid motion, strong seismicity and well defined boundaries. Tectonic activity across the Andes results from the Nazca Plate subducting under the South American plate in a series of discrete platelets with different widths and dip angles. This in turn, is reflected in the tectonic complexity of the Andes which are a multitutde of orogenic belts superimposed on each other since the Precambrian. Sites for Crustal Dynamics Program measurements are being located to investigate both interplate and extraplate motions. Observing operations have already been initiated at Arequipa, Peru and Easter Island, Santiago and Cerro Tololo, Chile. Sites under consideration include Iquique, Chile; Oruro and Santa Cruz, Bolivia; Cuzco, Lima, Huancayo and Bayovar, Peru; and Quito and the Galapagos Islands, Ecuador. Based on scientific considerations, Santa Cruz, Huancayo (or Lima), Quito and the Galapagos Islands should be replaced by Isla San Felix, Chile; Brazilia or Petrolina, Brazil; and Guayaquil, Ecuador. If resources permit, additional important sites would be Buenaventura and Villavicencio or Puerto La Concordia, Colombia; and Mendoza and Cordoba, Argentina.

  4. Tracing the history of submarine hydrothermal inputs and the significance of hydrothermal hafnium for the seawater budget - A combined Pb-Hf-Nd isotope approach

    USGS Publications Warehouse

    van de Flierdt, T.; Frank, M.; Halliday, A.N.; Hein, J.R.; Hattendorf, B.; Gunther, D.; Kubik, P.W.

    2004-01-01

    Secular variations in the Pb isotopic composition of a mixed hydrogenous-hydrothermal ferromanganese crust from the Bauer Basin in the eastern Equatorial Pacific provide clear evidence for changes in hydrothermal contributions during the past 7 Myr. The nearby Galapagos Rise spreading center provided a strong hydrothermal flux prior to 6.5 Ma. After 6.5 Ma, the Pb became stepwise more radiogenic and more similar to Equatorial Pacific seawater, reflecting the westward shift of spreading to the presently active East Pacific Rise (EPR). A second, previously unrecognized enhanced hydrothermal period occurred between 4.4 and 2.9 Ma, which reflects either off-axis hydrothermal activity in the Bauer Basin or a late-stage pulse of hydrothermal Pb from the then active, but waning Galapagos Rise spreading center. Hafnium isotope time-series of the same mixed hydrogenous-hydrothermal crust show invariant values over the past 7 Myr. Hafnium isotope ratios, as well as Nd isotope ratios obtained for this crust, are identical to that of hydrogenous Equatorial Pacific deep water crusts and clearly indicate that hydrothermal Hf, similar to Nd, does not travel far from submarine vents. Therefore, we suggest that hydrothermal Hf fluxes do not contribute significantly to the global marine Hf budget. ?? 2004 Elsevier B.V. All rights reserved.

  5. Andean tectonics: Implications for Satellite Geodesy

    NASA Technical Reports Server (NTRS)

    Allenby, R. J.

    1984-01-01

    Current knowledge and theories of large scale Andean tectonics as they relate to site planning for the NASA Crustal Dynamics Program's proposed high precision geodetic measurements of relative motions between the Nazca and South American plates are summarized. The Nazca Plate and its eastern margin, the Peru-Chile Trench, is considered a prototype plate marked by rapid motion, strong seismicity and well defined boundaries. Tectonic activity across the Andes results from the Nazca Plate subducting under the South American plate in a series of discrete platelets with different widths and dip angles. This in turn, is reflected in the tectonic complexity of the Andes which are a multitutde of orogenic belts superimposed on each other since the Precambrian. Sites for Crustal Dynamics Program measurements are being located to investigate both interplate and extraplate motions. Observing operations have already been initiated at Arequipa, Peru and Easter Island, Santiago and Cerro Tololo, Chile. Sites under consideration include Iquique, Chile; Oruro and Santa Cruz, Bolivia; Cuzco, Lima, Huancayo and Bayovar, Peru; and Quito and the Galapagos Islands, Ecuador. Based on scientific considerations, Santa Cruz, Huancayo (or Lima), Quito and the Galapagos Islands should be replaced by Isla San Felix, Chile; Brazilia or Petrolina, Brazil; and Guayaquil, Ecuador. If resources permit, additional important sites would be Buenaventura and Villavicencio or Puerto La Concordia, Colombia; and Mendoza and Cordoba, Argentina.

  6. Multiple Distant Origins for Green Sea Turtles Aggregating off Gorgona Island in the Colombian Eastern Pacific

    PubMed Central

    Amorocho, Diego F.; Abreu-Grobois, F. Alberto; Dutton, Peter H.; Reina, Richard D.

    2012-01-01

    Mitochondrial DNA analyses have been useful for resolving maternal lineages and migratory behavior to foraging grounds (FG) in sea turtles. However, little is known about source rookeries and haplotype composition of foraging green turtle aggregations in the southeastern Pacific. We used mitochondrial DNA control region sequences to identify the haplotype composition of 55 green turtles, Chelonia mydas, captured in foraging grounds of Gorgona National Park in the Colombian Pacific. Amplified fragments of the control region (457 bp) revealed the presence of seven haplotypes, with haplotype (h) and nucleotide (π) diversities of h = 0.300±0.080 and π = 0.009±0.005 respectively. The most common haplotype was CMP4 observed in 83% of individuals, followed by CMP22 (5%). The genetic composition of the Gorgona foraging population primarily comprised haplotypes that have been found at eastern Pacific rookeries including Mexico and the Galapagos, as well as haplotypes of unknown stock origin that likely originated from more distant western Pacific rookeries. Mixed stock analysis suggests that the Gorgona FG population is comprised mostly of animals from the Galapagos rookery (80%). Lagrangian drifter data showed that movement of turtles along the eastern Pacific coast and eastward from distant western and central Pacific sites was possible through passive drift. Our results highlight the importance of this protected area for conservation management of green turtles recruited from distant sites along the eastern Pacific Ocean. PMID:22319635

  7. The Sr/Ca-temperature relationship in coralline aragonite: Influence of variability in (Sr/Ca)[sub seawater] and skeletal growth parameters

    SciTech Connect

    de Villiers, S.; Shen, G.T.; Nelson, B.K. )

    1994-01-01

    This paper provides an evaluation of two of the most likely pitfalls of Sr/Ca thermometry, i.e., the effect of biogenic cycling of Sr vs. Ca in the surface ocean and the effect of variable extension rate on Sr incorporation in coralline aragonite. The authors also report calibration of the Sr/Ca-temperature relationship for three coral species, Porites lobata, Pocillopora eydouxi, and Pavona clavus, collected for the Hawaiian and Galapagos islands. Analyses of seawater samples show significant spatial and depth variability in the Sr:Ca ratio. The uncertainty introduced by this effect is estimated to be <0.2[degrees]C for corals located in tropical oligotrophic waters, and potentially larger for corals located in upwelling areas. Sr/Ca along two different growth axes of a Galapagos Pavona clavus, with annual extension rates of [approximately]6 and 12 mm/y, respectively, indicate an offset of 1-2[degrees]C, with higher Sr/Ca values associated with slower extension rates. The offset observed between the two growth axes may be the result of variations in extension and/or calcification rate. These results are important in determining past sea surface temperatures for reconstruction of paleoclimates.

  8. Differences in foraging ecology align with genetically divergent ecotypes of a highly mobile marine top predator.

    PubMed

    Jeglinski, Jana W E; Wolf, Jochen B W; Werner, Christiane; Costa, Daniel P; Trillmich, Fritz

    2015-12-01

    Foraging differentiation within a species can contribute to restricted gene flow between ecologically different groups, promoting ecological speciation. Galapagos sea lions (Zalophus wollebaeki) show genetic and morphological divergence between the western and central archipelago, possibly as a result of an ecologically mediated contrast in the marine habitat. We use global positioning system (GPS) data, time-depth recordings (TDR), stable isotope and scat data to compare foraging habitat characteristics, diving behaviour and diet composition of Galapagos sea lions from a western and a central colony. We consider both juvenile and adult life stages to assess the potential role of ontogenetic shifts that can be crucial in shaping foraging behaviour and habitat choice for life. We found differences in foraging habitat use, foraging style and diet composition that aligned with genetic differentiation. These differences were consistent between juvenile and adult sea lions from the same colony, overriding age-specific behavioural differences. Our study contributes to an understanding of the complex interaction of ecological condition, plastic behavioural response and genetic make-up of interconnected populations.

  9. Holocene ENSO Reconstructions from Molecular Rain Gauges

    NASA Astrophysics Data System (ADS)

    Sachs, J. P.; Zhang, Z.; Smittenberg, R.; Saenger, C.; Pahnke, K.; Koutavas, A.

    2005-12-01

    The response ENSO to the mean climate state is poorly understood. Paleoclimate records of ENSO variability under different climate boundary conditions are needed to validate models but remain few and far between. Most existing records are from single cores or locations, are constructed from a single paleo-environmental proxy, and span a short time interval. In light of this paucity of data we are constructing a continuous history of ENSO-related rainfall anomalies, spanning the Holocene, from a wide diversity of settings across the equatorial Pacific, using a multitude of biomarker and molecular isotopic (D/H, 13C/12C) measurements. During 2004-2005 we collected sediment cores from equatorial lakes, bogs, hypersaline basins, and marine sediments in Palau (western Pacific), Kiribati and the Galapagos (central Pacific), and the Panama Basin (eastern Pacific). Each location was specifically targeted for its centrality in one of three zones of anomalous ENSO-related rainfall. Each water body cored was targeted for its sensitivity to rainfall variations. Many of the cores have sediment accumulation rates, derived from Pb-210 and C-14, that exceed 1 m/kyr, permitting decadal resolution. Here we report on our findings to date. Biomarker and molecular D/H records of drought in Palau, high lake levels in the Galapagos, and diminished Andean runoff to the Panama Basin indicate a late Holocene increase in El Nino frequency and/or intensity.

  10. Petrological evidence for secular cooling in mantle plumes.

    PubMed

    Herzberg, Claude; Gazel, Esteban

    2009-04-01

    Geological mapping and geochronological studies have shown much lower eruption rates for ocean island basalts (OIBs) in comparison with those of lavas from large igneous provinces (LIPs) such as oceanic plateaux and continental flood provinces. However, a quantitative petrological comparison has never been made between mantle source temperature and the extent of melting for OIB and LIP sources. Here we show that the MgO and FeO contents of Galapagos-related lavas and their primary magmas have decreased since the Cretaceous period. From petrological modelling, we infer that these changes reflect a cooling of the Galapagos mantle plume from a potential temperature of 1,560-1,620 degrees C in the Cretaceous to 1,500 degrees C at present. Iceland also exhibits secular cooling, in agreement with previous studies. Our work provides quantitative petrological evidence that, in general, mantle plumes for LIPs with Palaeocene-Permian ages were hotter and melted more extensively than plumes of more modern ocean islands. We interpret this to reflect episodic flow from lower-mantle domains that are lithologically and geochemically heterogeneous.

  11. Multiple distant origins for green sea turtles aggregating off Gorgona Island in the Colombian eastern Pacific.

    PubMed

    Amorocho, Diego F; Abreu-Grobois, F Alberto; Dutton, Peter H; Reina, Richard D

    2012-01-01

    Mitochondrial DNA analyses have been useful for resolving maternal lineages and migratory behavior to foraging grounds (FG) in sea turtles. However, little is known about source rookeries and haplotype composition of foraging green turtle aggregations in the southeastern Pacific. We used mitochondrial DNA control region sequences to identify the haplotype composition of 55 green turtles, Chelonia mydas, captured in foraging grounds of Gorgona National Park in the Colombian Pacific. Amplified fragments of the control region (457 bp) revealed the presence of seven haplotypes, with haplotype (h) and nucleotide (π) diversities of h = 0.300±0.080 and π = 0.009±0.005 respectively. The most common haplotype was CMP4 observed in 83% of individuals, followed by CMP22 (5%). The genetic composition of the Gorgona foraging population primarily comprised haplotypes that have been found at eastern Pacific rookeries including Mexico and the Galapagos, as well as haplotypes of unknown stock origin that likely originated from more distant western Pacific rookeries. Mixed stock analysis suggests that the Gorgona FG population is comprised mostly of animals from the Galapagos rookery (80%). Lagrangian drifter data showed that movement of turtles along the eastern Pacific coast and eastward from distant western and central Pacific sites was possible through passive drift. Our results highlight the importance of this protected area for conservation management of green turtles recruited from distant sites along the eastern Pacific Ocean.

  12. Pb isotopes in sulfides from mid-ocean ridge hydrothermal sites

    SciTech Connect

    LeHuray, A.P.; Church, S.E.; Koski, R.A.; Bouse, R.M.

    1988-04-01

    The authors report Pb isotope ratios of sulfides deposited at seven recently active mid-ocean ridge (MOR) hydrothermal vents. Sulfides from three sediment-starved sites on the Juan de Fuca Ridge contain Pb with isotope ratios identical to their local basaltic sources. Lead in two deposits from the sediment-covered Escanaba Trough, Gorda Ridge, is derived from the sediments and does not appear to contain any basaltic component. There is a range of isotope ratios in a Guaymas Basin deposit, consistent with a mixture of sediment and MOR basalt Pb. Lead in a Galapagos deposit differs slightly from known Galapagos basalt Pb isotope values. The faithful record of Pb isotope signatures of local sources in MOR sulfides indicates that isotope ratios from ancient analogues ca be used as accurate reflections of ancient oceanic crustal values in ophiolite-hosted deposits and continental crustal averages in sediment-hosted deposits. The preservation of primary ophiolitic or continental crustal Pb isotope signatures in ancient MOR sulfides provides a powerful tool for investigation of crustal evolution and for fingerprinting ancient terranes.

  13. Space-geodetic estimation of the nazca-south america euler vector

    NASA Astrophysics Data System (ADS)

    Angermann, D.; Klotz, J.; Reigber, C.

    1999-09-01

    GPS data from four sites in the Nazca Plate (Easter Island, Galapagos, Robinson Crusoe and San Felix Islands) and from five sites in the stable core of the South American Plate enabled us to estimate the Euler vector of the Nazca Plate with respect to South America. The observed velocities of Easter Island (6.6 cm/yr at 102.3°), Galapagos (5.1 cm/yr at 90.0°), Robinson Crusoe (6.6 cm/yr at 80.1°) and San Felix (6.0 cm/yr at 82.1°) are significantly slower than the global plate model NUVEL-1A velocites for those four sites. Our estimated Euler pole is located at 48.8°N, 91.7°W with a rate of 0.59°/m.y. The NUVEL-1A and earlier space-geodetic studies give rotation rates that are 20% faster.

  14. The El Salvador and Philippines Tsunamis of August 2012: Insights from Sea Level Data Analysis and Numerical Modeling

    NASA Astrophysics Data System (ADS)

    Heidarzadeh, Mohammad; Satake, Kenji

    2014-12-01

    We studied two tsunamis from 2012, one generated by the El Salvador earthquake of 27 August ( Mw 7.3) and the other generated by the Philippines earthquake of 31 August ( Mw 7.6), using sea level data analysis and numerical modeling. For the El Salvador tsunami, the largest wave height was observed in Baltra, Galapagos Islands (71.1 cm) located about 1,400 km away from the source. The tsunami governing periods were around 9 and 19 min. Numerical modeling indicated that most of the tsunami energy was directed towards the Galapagos Islands, explaining the relatively large wave height there. For the Philippines tsunami, the maximum wave height of 30.5 cm was observed at Kushimoto in Japan located about 2,700 km away from the source. The tsunami governing periods were around 8, 12 and 29 min. Numerical modeling showed that a significant part of the far-field tsunami energy was directed towards the southern coast of Japan. Fourier and wavelet analyses as well as numerical modeling suggested that the dominant period of the first wave at stations normal to the fault strike is related to the fault width, while the period of the first wave at stations in the direction of fault strike is representative of the fault length.

  15. Phylogenetic relationships of the mockingbirds and thrashers (Aves: Mimidae).

    PubMed

    Lovette, Irby J; Arbogast, Brian S; Curry, Robert L; Zink, Robert M; Botero, Carlos A; Sullivan, John P; Talaba, Amanda L; Harris, Rebecca B; Rubenstein, Dustin R; Ricklefs, Robert E; Bermingham, Eldredge

    2012-05-01

    The mockingbirds, thrashers and allied birds in the family Mimidae are broadly distributed across the Americas. Many aspects of their phylogenetic history are well established, but there has been no previous phylogenetic study that included all species in this radiation. Our reconstructions based on mitochondrial and nuclear DNA sequence markers show that an early bifurcation separated the Mimidae into two clades, the first of which includes North and Middle American taxa (Melanotis, Melanoptila, Dumetella) plus a small radiation that likely occurred largely within the West Indies (Ramphocinclus, Allenia, Margarops, Cinclocerthia). The second and larger radiation includes the Toxostoma thrasher clade, along with the monotypic Sage Thrasher (Oreoscoptes) and the phenotypically diverse and broadly distributed Mimus mockingbirds. This mockingbird group is biogeographically notable for including several lineages that colonized and diverged on isolated islands, including the Socorro Mockingbird (Mimus graysoni, formerly Mimodes) and the diverse and historically important Galapagos mockingbirds (formerly Nesomimus). Our reconstructions support a sister relationship between the Galapagos mockingbird lineage and the Bahama Mockingbird (M. gundlachi) of the West Indies, rather than the Long-tailed Mockingbird (M. longicaudatus) or other species presently found on the South American mainland. Relationships within the genus Toxostoma conflict with traditional arrangements but support a tree based on a preivous mtDNA study. For instance, the southern Mexican endemic Ocellated Thrasher (T. ocellatum) is not an isolated sister species of the Curve-billed thrasher (T. curvirostre).

  16. Diversity of Thiosulfate-Oxidizing Bacteria from Marine Sediments and Hydrothermal Vents†

    PubMed Central

    Teske, A.; Brinkhoff, T.; Muyzer, G.; Moser, D. P.; Rethmeier, J.; Jannasch, H. W.

    2000-01-01

    Species diversity, phylogenetic affiliations, and environmental occurrence patterns of thiosulfate-oxidizing marine bacteria were investigated by using new isolates from serially diluted continental slope and deep-sea abyssal plain sediments collected off the coast of New England and strains cultured previously from Galapagos hydrothermal vent samples. The most frequently obtained new isolates, mostly from 103- and 104-fold dilutions of the continental slope sediment, oxidized thiosulfate to sulfate and fell into a distinct phylogenetic cluster of marine alpha-Proteobacteria. Phylogenetically and physiologically, these sediment strains resembled the sulfate-producing thiosulfate oxidizers from the Galapagos hydrothermal vents while showing habitat-related differences in growth temperature, rate and extent of thiosulfate utilization, and carbon substrate patterns. The abyssal deep-sea sediments yielded predominantly base-producing thiosulfate-oxidizing isolates related to Antarctic marine Psychroflexus species and other cold-water marine strains of the Cytophaga-Flavobacterium-Bacteroides phylum, in addition to gamma-proteobacterial isolates of the genera Pseudoalteromonas and Halomonas-Deleya. Bacterial thiosulfate oxidation is found in a wide phylogenetic spectrum of Flavobacteria and Proteobacteria. PMID:10919760

  17. Petrological evidence for secular cooling in mantle plumes.

    PubMed

    Herzberg, Claude; Gazel, Esteban

    2009-04-01

    Geological mapping and geochronological studies have shown much lower eruption rates for ocean island basalts (OIBs) in comparison with those of lavas from large igneous provinces (LIPs) such as oceanic plateaux and continental flood provinces. However, a quantitative petrological comparison has never been made between mantle source temperature and the extent of melting for OIB and LIP sources. Here we show that the MgO and FeO contents of Galapagos-related lavas and their primary magmas have decreased since the Cretaceous period. From petrological modelling, we infer that these changes reflect a cooling of the Galapagos mantle plume from a potential temperature of 1,560-1,620 degrees C in the Cretaceous to 1,500 degrees C at present. Iceland also exhibits secular cooling, in agreement with previous studies. Our work provides quantitative petrological evidence that, in general, mantle plumes for LIPs with Palaeocene-Permian ages were hotter and melted more extensively than plumes of more modern ocean islands. We interpret this to reflect episodic flow from lower-mantle domains that are lithologically and geochemically heterogeneous. PMID:19340079

  18. New Radiometric Age Constraints for the Matuyama-Bruhnes Reversal and Santa Rosa Excursion

    NASA Astrophysics Data System (ADS)

    Balbas, A.; Koppers, A. A. P.; Kent, D. V.; Coe, R. S.; Konrad, K.; Clark, P. U.

    2015-12-01

    The coupling of the timing of the virtual geomagnetic pole (VGP) position and the absolute paleointensities for geomagnetic events is vital for understanding the Earth's geodynamo. Here we present new high-precision 40Ar/39Ar age determinations using an ARGUS-VI multi-collector mass spectrometer for lava flows on Floreana Island, Galapagos, and Tahiti Nui, Society Islands. New Galapagos ages (n=6) place the GA-79 lava flow on Floreana Island, which records an excursional VGP from an equatorial region (Cox and Dalrymple, 1966), within the Santa Rosa excursion. This flow contains extremely low paleointesity values of 1.1 x 1022 Am2 (n=11; Wang and Kent, 2013). We also present 52 new ages on 18 lava flows from the Punaruu valley, Tahiti, which record the Matuyama-Bruhnes reversal. The new ages confirm that the lavas record this reversal, but the ages differ from the original stratigraphy presented in Mochizuki et al. (2011). Our new ages using the Kuiper et al. (2008) fish canyon sanidine ages for Punaruu valley lava flows are concordant with previous astronomically tuned ages (Channell et al. 2002, 2009) and represent the highest precision radiometric ages for the most recent reversal. Here we show that paleointensity lows associated with excursional events can be comparable to or less than those associated with reversals. In addition, such field strength reductions can occur in time intervals as short as 3 thousand years.

  19. Industry and Academic Consortium for Computer Based Subsurface Geology Laboratory

    NASA Astrophysics Data System (ADS)

    Brown, A. L.; Nunn, J. A.; Sears, S. O.

    2008-12-01

    Twenty two licenses for Petrel Software acquired through a grant from Schlumberger are being used to redesign the laboratory portion of Subsurface Geology at Louisiana State University. The course redesign is a cooperati