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Sample records for eastern north pacific

  1. Status of marine mammals in the eastern North Pacific Ocean

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report covers the status or marine mammals in the eastern north Pacific Ocean. Species covered are: sea otter, northern, Guadalupe fur seals, stellar,...

  2. Eastern tropical North Pacific coral radiocarbon reveals North Pacific Gyre Oscillation (NPGO) variability

    Science.gov (United States)

    Rafter, Patrick A.; Sanchez, Sara C.; Ferguson, Julie; Carriquiry, Jose D.; Druffel, Ellen R. M.; Villaescusa, J. A.; Southon, John R.

    2017-03-01

    Fluctuations in oceanic circulation and upwelling associated with the North Pacific Gyre Oscillation (NPGO) are the largest source of salinity and nutrient concentration variability across the Pacific basin. Recent observations suggest NPGO-like variability is intensifying, but longer, "pre-instrumental" records are required to improve our understanding of NPGO amplitude and phase change. Here, using measurements of coral skeletal chemistry from San Benedicto Island in the Eastern Tropical North Pacific (ETNP), we assess this region's suitability for reconstructing NPGO behavior. We find that coral geochemical proxy measurements of ETNP salinity and dissolved inorganic carbon radiocarbon (Δ14C) content reflect NPGO-driven gyre circulation and regional coastal upwelling. These results provide the basis for reconstructing NPGO-related ocean conditions hundreds of years prior to the modern observational record.

  3. 75 FR 68756 - Eastern North Pacific Gray Whale; Notice of Petition Availability

    Science.gov (United States)

    2010-11-09

    ... National Oceanic and Atmospheric Administration RIN 0648-XA018 Eastern North Pacific Gray Whale; Notice of... Pacific population of gray whales (Eschrichtius robustus) as a depleted stock under the Marine Mammal... assessment report for Eastern North Pacific gray whales is available on the Internet at the following...

  4. North Pacific Eastern Subtropical Mode Water simulation and future projection

    Institute of Scientific and Technical Information of China (English)

    XIA Ruibin; LIU Qinyu; XU Lixiao; LU Yiqun

    2015-01-01

    The present climate simulation and future projection of the Eastern Subtropical Mode Water (ESTMW) in the North Pacific are investigated based on the Geophysical Fluid Dynamics Laboratory Earth System Model (GFDL-ESM2M). Spatial patterns of the mixed layer depth (MLD) in the eastern subtropical North Pacific and the ESTMW are well simulated using this model. Compared with historical simulation, the ESTMW is produced at lighter isopycnal surfaces and its total volume is decreased in the RCP8.5 runs, because the subduction rate of the ESTMW decreases by 0.82×10−6 m/s during February–March. In addition, it is found that the lateral induction decreasing is approximately four times more than the Ekman pumping, and thus it plays a dominant role in the decreased subduction rate associated with global warming. Moreover, the MLD during February–March is banded shoaling in response to global warming, extending northeastward from the east of the Hawaii Islands (20°N, 155°W) to the west coast of North America (30°N, 125°W), with a max-imum shoaling of 50 m, and then leads to the lateral induction reduction. Meanwhile, the increased north-eastward surface warm current to the east of Hawaii helps strengthen of the local upper ocean stratification and induces the banded shoaling MLD under warmer climate. This new finding indicates that the ocean surface currents play an important role in the response of the MLD and the ESTMW to global warming.

  5. Historical Eastern North Pacific Tropical Cyclone Tracks, 1949-2004 - Direct Download

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This Historical Eastern North Pacific Tropical Cyclone Tracks file contains the six-hourly (0000, 0600, 1200, 1800 UTC) center locations and intensities for all...

  6. 75 FR 70903 - Eastern North Pacific Gray Whale; Notice of Extension of Public Comment Period on Marine Mammal...

    Science.gov (United States)

    2010-11-19

    ... on the petition (75 FR 68756). That Federal Register notice began NMFS' 15-day public comment period... National Oceanic and Atmospheric Administration RIN 0648-XA018 Eastern North Pacific Gray Whale; Notice of... petition to designate the Eastern North Pacific population of gray whales (Eschrichtius robustus) as...

  7. Northern fulmars as biological monitors of trends of plastic pollution in the eastern North Pacific.

    Science.gov (United States)

    Avery-Gomm, Stephanie; O'Hara, Patrick D; Kleine, Lydia; Bowes, Victoria; Wilson, Laurie K; Barry, Karen L

    2012-09-01

    Marine plastic debris is a global issue, which highlights the need for internationally standardized methods of monitoring plastic pollution. The stomach contents of beached northern fulmar (Fulmarus glacialis) have proven a cost-effective biomonitor in Europe. However, recent information on northern fulmar plastic ingestion is lacking in the North Pacific. We quantified the stomach contents of 67 fulmars from beaches in the eastern North Pacific in 2009-2010 and found that 92.5% of fulmars had ingested an average of 36.8 pieces, or 0.385 g of plastic. Plastic ingestion in these fulmars is among the highest recorded globally. Compared to earlier studies in the North Pacific, our findings indicate an increase in plastic ingestion over the past 40 years. This study substantiates the use of northern fulmar as biomonitors of plastic pollution in the North Pacific and suggests that the high levels of plastic pollution in this region warrant further monitoring.

  8. Estimating historical eastern North Pacific blue whale catches using spatial calling patterns.

    Directory of Open Access Journals (Sweden)

    Cole C Monnahan

    Full Text Available Blue whales (Balaenoptera musculus were exploited extensively around the world and remain endangered. In the North Pacific their population structure is unclear and current status unknown, with the exception of a well-studied eastern North Pacific (ENP population. Despite existing abundance estimates for the ENP population, it is difficult to estimate pre-exploitation abundance levels and gauge their recovery because historical catches of the ENP population are difficult to separate from catches of other populations in the North Pacific. We collated previously unreported Soviet catches and combined these with known catches to form the most current estimates of North Pacific blue whale catches. We split these conflated catches using recorded acoustic calls from throughout the North Pacific, the knowledge that the ENP population produces a different call than blue whales in the western North Pacific (WNP. The catches were split by estimating spatiotemporal occurrence of blue whales with generalized additive models fitted to acoustic call patterns, which predict the probability a catch belonged to the ENP population based on the proportion of calls of each population recorded by latitude, longitude, and month. When applied to the conflated historical catches, which totaled 9,773, we estimate that ENP blue whale catches totaled 3,411 (95% range 2,593 to 4,114 from 1905-1971, and amounted to 35% (95% range 27% to 42% of all catches in the North Pacific. Thus most catches in the North Pacific were for WNP blue whales, totaling 6,362 (95% range 5,659 to 7,180. The uncertainty in the acoustic data influence the results substantially more than uncertainty in catch locations and dates, but the results are fairly insensitive to the ecological assumptions made in the analysis. The results of this study provide information for future studies investigating the recovery of these populations and the impact of continuing and future sources of anthropogenic

  9. Estimating historical eastern North Pacific blue whale catches using spatial calling patterns.

    Science.gov (United States)

    Monnahan, Cole C; Branch, Trevor A; Stafford, Kathleen M; Ivashchenko, Yulia V; Oleson, Erin M

    2014-01-01

    Blue whales (Balaenoptera musculus) were exploited extensively around the world and remain endangered. In the North Pacific their population structure is unclear and current status unknown, with the exception of a well-studied eastern North Pacific (ENP) population. Despite existing abundance estimates for the ENP population, it is difficult to estimate pre-exploitation abundance levels and gauge their recovery because historical catches of the ENP population are difficult to separate from catches of other populations in the North Pacific. We collated previously unreported Soviet catches and combined these with known catches to form the most current estimates of North Pacific blue whale catches. We split these conflated catches using recorded acoustic calls from throughout the North Pacific, the knowledge that the ENP population produces a different call than blue whales in the western North Pacific (WNP). The catches were split by estimating spatiotemporal occurrence of blue whales with generalized additive models fitted to acoustic call patterns, which predict the probability a catch belonged to the ENP population based on the proportion of calls of each population recorded by latitude, longitude, and month. When applied to the conflated historical catches, which totaled 9,773, we estimate that ENP blue whale catches totaled 3,411 (95% range 2,593 to 4,114) from 1905-1971, and amounted to 35% (95% range 27% to 42%) of all catches in the North Pacific. Thus most catches in the North Pacific were for WNP blue whales, totaling 6,362 (95% range 5,659 to 7,180). The uncertainty in the acoustic data influence the results substantially more than uncertainty in catch locations and dates, but the results are fairly insensitive to the ecological assumptions made in the analysis. The results of this study provide information for future studies investigating the recovery of these populations and the impact of continuing and future sources of anthropogenic mortality.

  10. Invasive range expansion by the Humboldt squid, Dosidicus gigas, in the eastern North Pacific.

    Science.gov (United States)

    Zeidberg, Louis D; Robison, Bruce H

    2007-07-31

    A unique 16-year time series of deep video surveys in Monterey Bay reveals that the Humboldt squid, Dosidicus gigas, has substantially expanded its perennial geographic range in the eastern North Pacific by invading the waters off central California. This sustained range expansion coincides with changes in climate-linked oceanographic conditions and a reduction in competing top predators. It is also coincident with a decline in the abundance of Pacific hake, the most important commercial groundfish species off western North America. Recognizing the interactive effects of multiple changes in the environment is an issue of growing concern in ocean conservation and sustainability research.

  11. The feeding habits of slope dwelling macrourid fishes in the eastern North Pacific

    Science.gov (United States)

    Drazen, Jeffrey C.; Buckley, Troy W.; Hoff, Gerald R.

    2001-03-01

    The diet of slope dwelling macrourid fishes in the eastern North Pacific is poorly known. We collected several hundred stomach samples to investigate the feeding habits of Coryphaenoides acrolepis and Albatrossia pectoralis, the two dominant slope dwelling macrourids off the continental United States. Coryphaenoides acrolepis exhibited a pronounced ontogenetic shift in diet. Specimens 15 cm with scavenged food constituting approximately 20% of the weight of total prey and occurring in approximately 20% of fish 21-29 cm. Albatrossia pectoralis consumed primarily midwater fish and squid, and we believe that it feeds in the water column. There were significant differences between the diets of A. pectoralis and C. acrolepis suggesting some degree of niche separation between macrourid species on the continental slope of the eastern North Pacific. Both species are at the top of the food web on the upper continental slope and, because of their abundance, may exert significant pressures on their prey populations.

  12. AFSC/RACE/GAP/Conrath: Notes on the Reproductive Biology of Female Salmon Sharks in the Eastern North Pacific Ocean

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Little information has previously been published on the reproductive biology of the salmon shark in the Eastern North Pacific ocean. This data set incorporates basic...

  13. AFSC/NMML: Shore-based counts of the Eastern North Pacific gray whale stock from central California, 1967 - 2007

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Marine Fisheries Service (NMFS) has conducted shore-based counts of the Eastern North Pacific stock of gray whales (Eschrichtius robustus) 26 years from...

  14. Oxygen distribution and aerobic respiration in the north and south eastern tropical Pacific oxygen minimum zones

    DEFF Research Database (Denmark)

    Tiano, Laura; Garcia-Robledo, Emilio; Dalsgaard, Tage

    2014-01-01

    Highly sensitive STOX O-2 sensors were used for determination of in situ O-2 distribution in the eastern tropical north and south Pacific oxygen minimum zones (ETN/SP OMZs), as well as for laboratory determination of O-2 uptake rates of water masses at various depths within these OMZs. Oxygen...... was generally below the detection limit (few nmol L-1) in the core of both OMZs, suggesting the presence of vast volumes of functionally anoxic waters in the eastern Pacific Ocean. Oxygen was often not detectable in the deep secondary chlorophyll maximum found at some locations, but other secondary maxima...... efficiently at extremely low oxygen concentrations with apparent half-saturation concentrations (K-m values) ranging from about 10 to about 200 nmol L-1. (C) 2014 The Authors. Published by Elsevier Ltd....

  15. Insight into the Pacific Sea Surface Temperature- North American Hydroclimate Connection from an Eastern Tropical North Pacific Coral Record

    Science.gov (United States)

    Sanchez, S. C.; Charles, C. D.; Carriquiry, J. D.

    2015-12-01

    The last few years of record-breaking climate anomalies across North America--a resilient atmospheric ridge and extreme drought over the West Coast, and severe winters across the Midwest and East Coast regions--have been linked to anomalous Pacific sea surface temperatures (Seager et al. 2014, Wang et al. 2014, Hartmann 2015). The synoptic associations prompt important questions on the relation between these unusual phenomena and extreme expressions of known Pacific decadal modes, such as the North Pacific Gyre Oscillation (NPGO). These questions motivate our pursuit to document multiple realizations of decadal variability in the Pacific-North American region through periods of varied radiative forcing. Here we introduce a 178 year, seasonally resolved Porites coral record from Clarion Island (18N, 115W), the westernmost island of the Revillagigedo Archipelago, a region both highly influenced by NPGO SST and SSS variability and critical for NPGO tropical-extratropical communication via the Seasonal Footprinting Mechanism (Vimont et al. 2003). When coupled with tree ring records from the western United States (Griffin and Anchukaitis 2014, MacDonald and Case 2005) and coral records from the central tropical Pacific (Cobb et al. 2001), the δ18O signal from the Clarion coral offers an extended framework of coherent continental hydroclimate and oceanic variability across the Pacific basin beyond the instrumental record. Over the last 200 years, we find clear commonality in the timing, magnitude and spatial expression of variability (illustrated through the NADA Atlas, Cook et al. 2004) amongst the proxy records. The strong relationship between Northeastern Pacific Clarion and the Central Pacific Palmyra record with the North American hydroclimate records can be viewed within the mechanistic framework of the NPGO; this framework is then explored over the last millennium across intervals of varied radiative forcing.

  16. Examination of Health Effects and Long-Term Impacts of Deployments of Multiple Tag Types on Blue, Humpback, and Gray Whales in the Eastern North Pacific

    Science.gov (United States)

    2015-09-30

    deployments of multiple tag types on blue, humpback, and gray whales in the eastern North Pacific John Calambokidis Cascadia Research Collective 218...large whales including blue, humpback, and gray whales by conducting long term follow up of previously tagged individuals in the eastern North Pacific...humpback, and gray whales in the eastern North Pacific and our extensive monitoring of these populations. Despite extensive use of implant tags for more

  17. Whales, Dolphins, and Porpoises of the Eastern North Pacific and Adjacent Arctic Waters: A Guide to Their Identification.

    Science.gov (United States)

    Leatherwood, Stephen; And Others

    This field guide is designed to permit observers to identify the cetaceans (whales, dolphins, and porpoises) they see in the waters of the eastern North Pacific, including the Gulf of California, Hawaii, and the western Arctic of North America. The animals described are grouped not by scientific relationships but by similarities in appearance in…

  18. Whales, Dolphins, and Porpoises of the Eastern North Pacific and Adjacent Arctic Waters: A Guide to Their Identification.

    Science.gov (United States)

    Leatherwood, Stephen; And Others

    This field guide is designed to permit observers to identify the cetaceans (whales, dolphins, and porpoises) they see in the waters of the eastern North Pacific, including the Gulf of California, Hawaii, and the western Arctic of North America. The animals described are grouped not by scientific relationships but by similarities in appearance in…

  19. Temporal separation of two fin whale call types across the eastern North Pacific.

    Science.gov (United States)

    Sirović, Ana; Williams, Lauren N; Kerosky, Sara M; Wiggins, Sean M; Hildebrand, John A

    2013-01-01

    Fin whales (Balaenoptera physalus) produce a variety of low-frequency, short-duration, frequency-modulated calls. The differences in temporal patterns between two fin whale call types are described from long-term passive acoustic data collected intermittently between 2005 and 2011 at three locations across the eastern North Pacific: the Bering Sea, off Southern California, and in Canal de Ballenas in the northern Gulf of California. Fin whale calls were detected at all sites year-round, during all periods with recordings. At all three locations, 40-Hz calls peaked in June, preceding a peak in 20-Hz calls by 3-5 months. Monitoring both call types may provide a more accurate insight into the seasonal presence of fin whales across the eastern North Pacific than can be obtained from a single call type. The 40-Hz call may be associated with a foraging function, and temporal separation between 40- and 20-Hz calls may indicate the separation between predominately feeding behavior and other social interactions.

  20. Plastic ingestion in marine-associated bird species from the eastern North Pacific.

    Science.gov (United States)

    Avery-Gomm, S; Provencher, J F; Morgan, K H; Bertram, D F

    2013-07-15

    In addition to monitoring trends in plastic pollution, multi-species surveys are needed to fully understand the pervasiveness of plastic ingestion. We examined the stomach contents of 20 bird species collected from the coastal waters of the eastern North Pacific, a region known to have high levels of plastic pollution. We observed no evidence of plastic ingestion in Rhinoceros Auklet, Marbled Murrelet, Ancient Murrelet or Pigeon Guillemot, and low levels in Common Murre (2.7% incidence rate). Small sample sizes limit our ability to draw conclusions about population level trends for the remaining fifteen species, though evidence of plastic ingestion was found in Glaucous-Winged Gull and Sooty Shearwater. Documenting levels of plastic ingestion in a wide array of species is necessary to gain a comprehensive understanding about the impacts of plastic pollution. We propose that those working with bird carcasses follow standard protocols to assess the levels of plastic ingestion whenever possible.

  1. Response of North Pacific eastern subtropical mode water to greenhouse gas versus aerosol forcing

    Science.gov (United States)

    Li, Xiang; Luo, Yiyong

    2016-04-01

    Mode water is a distinct water mass characterized by a near vertical homogeneous layer or low potential vorticity, and is considered essential for understanding ocean climate variability. Based on the output of GFDL CM3, this study investigates the response of eastern subtropical mode water (ESTMW) in the North Pacific to two different single forcings: greenhouse gases (GHGs) and aerosol. Under GHG forcing, ESTMW is produced on lighter isopycnal surfaces and is decreased in volume. Under aerosol forcing, in sharp contrast, it is produced on denser isopycnal surfaces and is increased in volume. The main reason for the opposite response is because surface ocean-to-atmosphere latent heat flux change over the ESTMW formation region shoals the mixed layer and thus weakens the lateral induction under GHG forcing, but deepens the mixed layer and thus strengthens the lateral induction under aerosol forcing. In addition, local wind changes are also favorable to the opposite response of ESTMW production to GHG versus aerosol.

  2. Water column biogeochemistry of oxygen minimum zones in the eastern tropical North Atlantic and eastern tropical South Pacific oceans

    Science.gov (United States)

    Löscher, Carolin R.; Bange, Hermann W.; Schmitz, Ruth A.; Callbeck, Cameron M.; Engel, Anja; Hauss, Helena; Kanzow, Torsten; Kiko, Rainer; Lavik, Gaute; Loginova, Alexandra; Melzner, Frank; Meyer, Judith; Neulinger, Sven C.; Pahlow, Markus; Riebesell, Ulf; Schunck, Harald; Thomsen, Sören; Wagner, Hannes

    2016-06-01

    Recent modeling results suggest that oceanic oxygen levels will decrease significantly over the next decades to centuries in response to climate change and altered ocean circulation. Hence, the future ocean may experience major shifts in nutrient cycling triggered by the expansion and intensification of tropical oxygen minimum zones (OMZs), which are connected to the most productive upwelling systems in the ocean. There are numerous feedbacks among oxygen concentrations, nutrient cycling and biological productivity; however, existing knowledge is insufficient to understand physical, chemical and biological interactions in order to adequately assess past and potential future changes. In the following, we summarize one decade of research performed in the framework of the Collaborative Research Center 754 (SFB754) focusing on climate-biogeochemistry interactions in tropical OMZs. We investigated the influence of low environmental oxygen conditions on biogeochemical cycles, organic matter formation and remineralization, greenhouse gas production and the ecology in OMZ regions of the eastern tropical South Pacific compared to the weaker OMZ of the eastern tropical North Atlantic. Based on our findings, a coupling of primary production and organic matter export via the nitrogen cycle is proposed, which may, however, be impacted by several additional factors, e.g., micronutrients, particles acting as microniches, vertical and horizontal transport of organic material and the role of zooplankton and viruses therein.

  3. Critically endangered western gray whales migrate to the eastern North Pacific.

    Science.gov (United States)

    Mate, Bruce R; Ilyashenko, Valentin Yu; Bradford, Amanda L; Vertyankin, Vladimir V; Tsidulko, Grigory A; Rozhnov, Vyacheslav V; Irvine, Ladd M

    2015-04-01

    Western North Pacific gray whales (WGWs), once considered extinct, are critically endangered with unknown migratory routes and reproductive areas. We attached satellite-monitored tags to seven WGWs on their primary feeding ground off Sakhalin Island, Russia, three of which subsequently migrated to regions occupied by non-endangered eastern gray whales (EGWs). A female with the longest-lasting tag visited all three major EGW reproductive areas off Baja California, Mexico, before returning to Sakhalin Island the following spring. Her 22 511 km round-trip is the longest documented mammal migration and strongly suggests that some presumed WGWs are actually EGWs foraging in areas historically attributed to WGWs. The observed migration routes provide evidence of navigational skills across open water that break the near-shore north-south migratory paradigm of EGWs. Despite evidence of genetic differentiation, these tagging data indicate that the population identity of whales off Sakhalin Island needs further evaluation. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  4. Bite force and feeding kinematics in the eastern North Pacific Kyphosidae.

    Science.gov (United States)

    Moran, Clinton Joseph; Ferry, Lara

    2014-04-01

    Some fishes that feed on attached food items possess an intramandibular joint (IMJ), which is thought to increase maximum gape and facilitate contact between the tooth-bearing surface and the substrate. However, the mechanical consequences of using an IMJ to remove attached food items from the substrate are still poorly understood. We examined the most prominent eastern North Pacific kyphosid, the scraper: Girella nigricans and two other kyphosids, Medialuna californiensis and Hermosilla azurea, which occupy similar habitats. Of the three species, G. nigricans had the highest theoretical bite force per unit length. We examined the feeding mechanics of G. nigricans in two different feeding scenarios: a scraping behavior elicited on a block of brine shrimp gelatin and a picking behavior elicited on Ulva sp. We measured cranial elevation, lower jaw rotation, premaxillary protrusion, premaxillary rotation, gape maximum, and intramandibular rotation. Ulva treatments produced significantly greater cranial rotation, when compared to gelatin treatments. Gelatin treatments were associated with greater lower jaw rotation and larger gape. Premaxillary rotation and premaxillary protrusion did not differ between treatments. Intramandibular rotation occurred only when G. nigricans physically contacted the gelatin, suggesting the IMJ is a passive joint with no associated musculature. We also noted that G. nigricans do not appear to use suction to draw food into the mouth. The lack of suction and the presence of the IMJ suggest that the jaws of G. nigricans are specialized for maximizing jaw force when scraping.

  5. Authigenic gypsum found in gas hydrate-associated sediments from Hydrate Ridge, the eastern North Pacific

    Institute of Scientific and Technical Information of China (English)

    WANG; Jiasheng; Erwin; Suess; Dirk; Rickert

    2004-01-01

    Characteristic gypsum micro-sphere and granular mass were discovered by binocular microscope in the gas hydrate-associated sediments at cores SO143-221 and SO143/TVG40-2A respectively on Hydrate Ridge of Cascadia margin, the eastern North Pacific. XRD patterns and EPA analyses show both micro-sphere and granular mass of the crystals have the typical peaks and the typical main chemical compositions of gypsum, although their weight percents are slightly less than the others in the non-gas hydrate-associated marine regions. SEM pictures show that the gypsum crystals have clear crystal boundaries, planes, edges and cleavages of gypsum in form either of single crystal or of twin crystals. In view of the fact that there are meanwhile gas hydrate-associated authigenic carbonates and SO42(-rich pore water in the same sediment cores, it could be inferred reasonably that the gypsums formed also authigenically in the gas hydrate-associated environment too, most probably at the interface between the downward advecting sulfate-rich seawater and the below gas hydrate, which spilled calcium during its formation on Hydrate Ridge. The two distinct forms of crystal intergrowth, which are the granular mass of series single gypsum crystals at core SO143/TVG40-2A and the microsphere of gypsum crystals accompanied with detrital components at core SO143-221 respectively, indicate that they precipitated most likely in different interstitial water dynamic environments. So, the distinct authigenic gypsums found in gas hydrate-associated sediments on Hydrate Ridge could also be believed as one of the parameters which could be used to indicate the presence of gas hydrate in an unknown marine sediment cores.

  6. The record-breaking 2015 hurricane season in the eastern North Pacific: An analysis of environmental conditions

    Science.gov (United States)

    Collins, Jennifer M.; Klotzbach, Philip J.; Maue, Ryan N.; Roache, David R.; Blake, Eric S.; Paxton, Charles H.; Mehta, Christopher A.

    2016-09-01

    The presence of a near-record El Niño and a positive Pacific Meridional Mode provided an extraordinarily warm background state that fueled the 2015 eastern North Pacific hurricane season to near-record levels. We find that the western portion of the eastern North Pacific, referred to as the Western Development Region (WDR; 10°-20°N, 116°W-180°), set records for named storms, hurricane days, and Accumulated Cyclone Energy in 2015. When analyzing large-scale environmental conditions, we show that record warm sea surface temperatures, high midlevel relative humidity, high low-level relative vorticity, and record low vertical wind shear were among the environmental forcing factors contributing to the observed tropical cyclone activity. We assess how intraseasonal atmospheric variability may have contributed to active and inactive periods observed during the 2015 hurricane season. We document that, historically, active seasons are associated with May-June El Niño conditions, potentially allowing for predictability of future active WDR seasons.

  7. Eastern Pacific Ocean Conference

    Science.gov (United States)

    The promotion of interaction among investigators of all oceanographic disciplines studying the eastern Pacific Ocean was the goal of the 1990 Eastern Pacific Ocean Conference (EPOC), held October 17-19 on the snow-covered slopes of Mt. Hood, Oreg. Thirty oceanographers representing all disciplines attended.Dick Barber, Duke University Marine Lab, Beaufort, N.C., chaired a session on the eastern equatorial Pacific Ocean, emphasizing issues related to biological activity. Steve Ramp of the Naval Postgraduate School in Montery, Calif., chaired a session on recent results from northern and central California experiments. On October 19, following an early morning earthquake, a business meeting and discussions regarding a collaboration in future experiments were held.

  8. Evaluating controls on planktonic foraminiferal geochemistry in the Eastern Tropical North Pacific

    Science.gov (United States)

    Gibson, Kelly Ann; Thunell, Robert C.; Machain-Castillo, Maria Luisa; Fehrenbacher, Jennifer; Spero, Howard J.; Wejnert, Kate; Nava-Fernández, Xinantecatl; Tappa, Eric J.

    2016-10-01

    To explore relationships between water column hydrography and foraminiferal geochemistry in the Eastern Tropical North Pacific, we present δ18O and Mg/Ca records from three species of planktonic foraminifera, Globigerinoides ruber, Globigerina bulloides, and Globorotalia menardii, collected from a sediment trap mooring maintained in the Gulf of Tehuantepec from 2006-2012. Differences in δ18O between mixed-layer species G. ruber and G. bulloides and thermocline-dweller G. menardii track seasonal changes in upwelling. The records suggest an increase in upwelling during the peak positive phase of El Niño, and an overall reduction in stratification over the six-year period. For all three species, Mg/Ca ratios are higher than what has been reported in previous studies, and show poor correlations to calcification temperature. We suggest that low pH (7.6-8.0) and [3 2-CO] values (∼70-120 μmol/kg) in the mixed layer contribute to an overall trend of higher Mg/Ca ratios in this region. Laser Ablation Inductively Coupled Mass Spectrometry analyses of G. bulloides with high Mg/Ca ratios (>9 mmol/mol) reveal the presence of a secondary coating of inorganic calcite that has Mg/Ca and Mn/Ca ratios up to an order of magnitude higher than these elemental ratios in the primary calcite, along with elevated Sr/Ca and Ba/Ca ratios. Some of the samples with abnormally high Mg/Ca are found during periods of high primary productivity, suggesting the alteration may be related to changes in carbonate saturation resulting from remineralization of organic matter in oxygen-poor waters in the water column. Although similar shell layering has been observed on fossil foraminifera, this is the first time such alteration has been studied in shells collected from the water column. Our results suggest a role for seawater carbonate chemistry in influencing foraminiferal calcite trace element:calcium ratios prior to deposition on the seafloor, particularly in high-productivity, low

  9. Impacts of decaying eastern and central Pacific El Niños on tropical cyclone activities over the western North Pacific in summer

    Science.gov (United States)

    Yang, Yuxing; Xie, Ruihuang; Wang, Faming; Huang, Fei

    2016-07-01

    We investigate the influences of the decaying eastern Pacific El Niño (EP-El Niño) and central Pacific El Niño (CP-El Niño) on tropical cyclone (TC) activities in the western North Pacific (WNP) during July, August, and September (JAS). During this period, TC geneses and tracks are reduced in the central and eastern WNP. However, TC tracks reaching the Philippines increase, and more TC geneses appear west of 145°E during EP-El Niño. During CP-El Niño, tracks reaching the South China Sea (SCS) and southeast coast of China increase, and positive anomalies of TC genesis are found in the southern part of the central WNP and southern SCS. It is possible that the different variations of the anomalous anticyclone over east of the Philippines in the WNP induced by El Niños are instrumental to the different TC variations in the two types of decaying El Niños during JAS. Compared with EP-El Niño, strengthening and northward expansion of the anomalous anticyclone during CP-El Niño cause a westward shift of the western Pacific subtropical high in summer, which is responsible for more westward TC tracks over the SCS and southeast coast of China. This northward expansion can cause the center of suppressed TC geneses in the central WNP to migrate further north during CP-El Niño. A decreased magnitude of vertical shear dominates the southern part of the central WNP and southern SCS, which enhances TC formation in these regions during CP-El Niño.

  10. Acoustic detections of singing humpback whales (Megaptera novaeangliae) in the eastern North Pacific during their northbound migration.

    Science.gov (United States)

    Norris, T F; McDonald, M; Barlow, J

    1999-07-01

    Numerous (84) acoustic detections of singing humpback whales were made during a spring (08 March-09 June 1997) research cruise to study sperm whales in the central and eastern North Pacific. Over 15,000 km of track-line was surveyed acoustically using a towed hydrophone array. Additionally, 83 sonobuoys were deployed throughout the study area. Detection rates were greatest in late March, near the Hawaiian Islands, and in early April, northeast of the islands. Only one detection was made after April. Detection rates for sonobuoys were unequal in three equally divided longitudinal regions of the study area. Two high density clusters of detections occurred approximately 1200-2000 km northeast of the Hawaiian Islands and were attributed to a large aggregation of migrating animals. The distribution of these detections corroborates findings of previous studies. It is possible that these animals were maintaining acoustic contact during migration. Two unexpected clusters of singing whales were detected approximately 900 to 1000 km west of central and southern California. The location of these detections may indicate a previously undocumented migration route between an offshore breeding area, such as the Revillagigedo Islands, Mexico, and possible feeding areas in the western North Pacific or Bering Sea.

  11. Projected wave conditions in the Eastern North Pacific under the influence of two CMIP5 climate scenarios

    Science.gov (United States)

    Erikson, Li H.; Hegermiller, Christie; Barnard, Patrick; Ruggiero, Peter; van Ormondt, Martin

    2015-01-01

    Hindcast and 21st century winds, simulated by General Circulation Models (GCMs), were used to drive global- and regional-scale spectral wind-wave generation models in the Pacific Ocean Basin to assess future wave conditions along the margins of the North American west coast and Hawaiian Islands. Three-hourly winds simulated by four separate GCMs were used to generate an ensemble of wave conditions for a recent historical time-period (1976–2005) and projections for the mid and latter parts of the 21st century under two radiative forcing scenarios (RCP 4.5 and RCP 8.5), as defined by the fifth phase of the Coupled Model Inter-comparison Project (CMIP5) experiments. Comparisons of results from historical simulations with wave buoy and ERA-Interim wave reanalysis data indicate acceptable model performance of wave heights, periods, and directions, giving credence to generating projections. Mean and extreme wave heights are projected to decrease along much of the North American west coast. Extreme wave heights are projected to decrease south of ∼50°N and increase to the north, whereas extreme wave periods are projected to mostly increase. Incident wave directions associated with extreme wave heights are projected to rotate clockwise at the eastern end of the Aleutian Islands and counterclockwise offshore of Southern California. Local spatial patterns of the changing wave climate are similar under the RCP 4.5 and RCP 8.5 scenarios, but stronger magnitudes of change are projected under RCP 8.5. Findings of this study are similar to previous work using CMIP3 GCMs that indicates decreasing mean and extreme wave conditions in the Eastern North Pacific, but differ from other studies with respect to magnitude and local patterns of change. This study contributes toward a larger ensemble of global and regional climate projections needed to better assess uncertainty of potential future wave climate change, and provides model boundary conditions for assessing the impacts of

  12. Physical, chemical and biological CTD and bottle data from R/V Thomas G. Thompson cruise TN278 in eastern tropical North Pacific Ocean from March 19 to April 20, 2012 (NODC Accession 0109846)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This report contains data from R/V Thomas G. Thompson cruise TN278 to the eastern tropical north pacific oxygen deficient zone. The objective of the cruise was to...

  13. Shore-based counts of the Eastern North Pacific gray whale stock from central California conducted from 1967-12-18 to 2007-02-22 (NCEI Accession 0138007)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Marine Fisheries Service (NMFS) has conducted shore-based counts of the Eastern North Pacific stock of gray whales (Eschrichtius robustus) 26 years from...

  14. Tropical Cyclone Wind Probability Forecasting for the Eastern North Pacific (EPWINDP).

    Science.gov (United States)

    1982-04-01

    OFFICER DIRECTOR CHAIRMAN ATTN: WEATHER SERVICE OFFICE CENTRAL PACIFIC HURRICANE CEN. DLPI. 0F METEOROLOGY MARINE CORPS AIR STATION NWS, NOAA CALIfOrNIA...INSTITUTO DE GEOFISICA DIRECTOR HONOLULU, HI 96822 U.N.A.M. BIBLIOTECA NATIONAL HURRICANE CENTER TORRE DE CIENCIAS, 3ER PISO NOAA, GABLES ONE TOWER CHAIRMAN

  15. Size-fractionated diversity of eukaryotic microbial communities in the Eastern Tropical North Pacific oxygen minimum zone.

    Science.gov (United States)

    Duret, Manon T; Pachiadaki, Maria G; Stewart, Frank J; Sarode, Neha; Christaki, Urania; Monchy, Sébastien; Srivastava, Ankita; Edgcomb, Virginia P

    2015-05-01

    Oxygen minimum zones (OMZs) caused by water column stratification appear to expand in parts of the world's ocean, with consequences for marine biogeochemical cycles. OMZ formation is often fueled by high surface primary production, and sinking organic particles can be hotspots of interactions and activity within microbial communities. This study investigated the diversity of OMZ protist communities in two biomass size fractions (>30 and 30-1.6 μm filters) from the world's largest permanent OMZ in the Eastern Tropical North Pacific. Diversity was quantified via Illumina MiSeq sequencing of V4 region of 18S SSU rRNA genes in samples spanning oxygen gradients at two stations. Alveolata and Rhizaria dominated the two size fractions at both sites along the oxygen gradient. Community composition at finer taxonomic levels was partially shaped by oxygen concentration, as communities associated with versus anoxic waters shared only ∼32% of operational taxonomic unit (OTU) (97% sequence identity) composition. Overall, only 9.7% of total OTUs were recovered at both stations and under all oxygen conditions sampled, implying structuring of the eukaryotic community in this area. Size-fractionated communities exhibited different taxonomical features (e.g. Syndiniales Group I in the 1.6-30 μm fraction) that could be explained by the microniches created on the surface-originated sinking particles.

  16. Observations of heterogeneous reactions between Asian pollution and mineral dust over the Eastern North Pacific during INTEX-B

    Directory of Open Access Journals (Sweden)

    C. S. McNaughton

    2009-03-01

    Full Text Available In-situ airborne measurements of trace gases, aerosol size distributions, chemistry and optical properties were conducted over Mexico and the Eastern North Pacific during MILAGRO and INTEX-B. Heterogeneous reactions between secondary aerosol precursor gases and mineral dust during long-range transport lead to irreversible sequestration of sulfur and nitrogen compounds in the supermicrometer particulate size range.

    Simultaneous measurements of aerosol size distributions and weak-acid soluble calcium result in an estimate of 11 wt% of CaCO3 for Asian dust. During transport across the North Pacific, 10–30% of the CaCO3 is converted to CaSO4 or Ca(NO32 through reactions with trace gases. The 11-year record from the Mauna Loa Observatory confirm these findings, indicating that, on average, 16% of the CaCO3 has reacted to form CaSO4 and 14% has reacted to form Ca(NO32. Heterogeneous reactions resulting in ~3% increase in dust solubility is shown to have an insignificant effect on their optical properties compared to their variability in-situ. However, competition between supermicrometer dust and submicrometer primary aerosol for condensing secondary aerosol species led to a 25% smaller number median diameter for the accumulation mode aerosol. A 10–25% reduction of accumulation mode number median diameter results in a 30–70% reduction in submicrometer light scattering at relative humidities in the 80–95% range. At 80% RH submicrometer light scattering is only reduced ~3% due to a higher mass fraction of hydrophobic refractory components in the dust-affected accumulation mode aerosol. Thus reducing the geometric mean diameter of the submicrometer aerosol has a much larger effect on aerosol optics than changes to the hygroscopic:hydrophobic mass fractions of the aerosol.

    In the presence of dust, nitric acid concentrations are

  17. Understanding Differences in the Nitrogen Cycle in Low-Oxygen Zones in the Eastern Tropical North Pacific

    Science.gov (United States)

    Wood, C.; Travis, N. M.; Forbes, M. S.; Casciotti, K. L.

    2016-12-01

    Hypoxic and anoxic zones are found in oceans worldwide. These zones can be caused by warm water "caps" that trap colder water underneath the warm water so the cold water cannot replenish its oxygen. Processes such as global warming and eutrophication can also contribute to such oxygen-depleted zones. Thus, it is important to study these zones to investigate and reveal the impact humans have on ecosystems worldwide so we can fix the problems we have caused. The Eastern Tropical North Pacific (ETNP), off the southwestern coast of Mexico, contains a natural-oxygen deficient zone. On a research cruise to the ETNP in April 2016, incubations were conducted to measure the rates of nitrification in the upper water column (upper 100 m) at three stations. Incubations were conducted in light and dark bottles spiked with 15N-containing nitrite. In this study, nitrite concentration in incubation starting points was analyzed. For each point, four depths of increasing depth (they varied depending on the station) were analyzed, and for each depth there were three samples. For each sample five absorbance measurements were averaged to calculate nitrite concentration against known standards. Concentrations of nitrite were found to increase moving into the oxygen deficient zone. The nitrite peaks at the coastal stations were at shallower depths than the peak at the centermost station in the low-oxygen zone. At the centermost station within the oxygen-deficient region, the nitrite concentration at the primary peak was 1.6µM, which was the highest point out of all the stations. This nitrite concentration data will be expanded to all stations where 15N addition incubation experiments were performed. In the future, these time-zero data will be combined with time-24 data to calculate nitrite oxidation rates based on 15N isotope analysis. Measuring nitrite oxidation rates will help us further understand processes structuring nitrite accumulation in the ETNP low-oxygen zone.

  18. Modeling a habitat suitability index for the eastern fall cohort of Ommastrephes bartramii in the central North Pacific Ocean

    Institute of Scientific and Technical Information of China (English)

    CHEN Xinjun; TIAN Siquan; LIU Bilin; CHEN Yong

    2011-01-01

    The eastern fall cohort of the neon flying squid, Ommastrephes bartramii, has been commercially exploited by the Chinese squid jigging fleet in the central North Pacific Ocean since the late 1990s. To understand and identify their optimal habitat, we have developed a habitat suitability index (HSI) model using two potential important environmental variables - sea surface temperature (SST) and sea surface height anomaly (SSHA) - and fishery data from the main fishing ground (165°-180°E) during June and July of 1999-2003. A geometric mean model (GMM), minimum model (MM) and arithmetic weighted model (AWM) with different weights were compared and the best HSI model was selected using Akaike's information criterion (AIC). The performance of the developed HSI model was evaluated using fishery data for 2004. This study suggests that the highest catch per unit effort (CPUE) and fishing effort are closely related to SST and SSHA. The best SST- and SSHA-based suitability index (SI) regression models were SISST-bsed = 0.7SIeffort-SST + 0.3 SICPUE-SST, and SISSHA-based = 0.5SIeffon-SSHA + 0.5SICP,UE-SSHA,respectively, showing that fishing effort is more important than CPUE in the estimation of SI. The bestHSI model was the AWM, defined as HSI=0.3SISST-based+ 0.7SISSHA-based, indicating that SSHA is moreimportant than SST in estimating the HSI of squid. In 2004, monthly HSI values greater than 0.6 coincidedwith the distribution of productive fishing ground and high CPUE in June and July, suggesting that themodels perform well. The proposed model provides an important tool in our efforts to develop forecastingcapacity of squid spatial dynamics.

  19. Planktonic foraminifera as recorders of sea surface hydrography in the Eastern Tropical North Pacific (Gulf of Tehuantepec, MX)

    Science.gov (United States)

    Gibson, K.; Thunell, R.; Machain-Castillo, M. L.; Wejnert, K.; Nava-Fernández, X. A.; Rodriguez-Ramírez, A.; Tappa, E.

    2014-12-01

    The Gulf of Tehuanetpec (GoT) (14°-16°N and 92°-96°W) is located in the Eastern Tropical North Pacific, a region that is sensitive to changes in both Atlantic-Pacific water vapor transport as well as changes in ENSO. Within the ETNP, the GoT is unique in that it experiences significant changes in temperature (ΔT = 8-10°C) and salinity (ΔS = 3) associated with seasonal variations in precipitation and wind-driven upwelling. Establishing robust relationships between δ18O and Mg/Ca of foraminiferal calcite to sea surface temperature (SST) and sea surface salinity (SSS) in this region can then be used to study past changes in Atl-Pac water vapor transport and ENSO and how these relate to regional and global climate change. We present here a six year (2006-2012), weekly to biweekly resolved record of paired δ18O-Mg/Ca analyses of the planktonic foraminfer Globigerina bulloides, collected from a sediment trap mooring in the GoT (15° 38.826N, 95° 16.905 W). The G. bulloides δ18O values ranges from -0.14‰ to - 3.98‰, equivalent to ~16°C temperature, or nearly twice the observed instrumental change in SST. To help constrain the temperature influence on the δ18Ocalcite signal, Mg/Ca values were converted to temperature using previously published equations for G. bulloides. In addition, we calculated new equations using the Mg/Ca and satellite SST data. Depending on the calibration equation used, G. bulloides from the GoT show a ~5-8% change in Mg/Ca with temperature, and show generally good agreement with SST, particularly in winter upwelling months. The agreement between SST and Mg/Ca-based temperatures is less robust during the winter months of 2009, when a moderate El Niño year resulted in warmer and fresher surface conditions in the GoT than pervious and following years, indicating a deeper habitat depth for G. bulloides and perhaps reduced upwelling during El Niño conditions.

  20. Transport of North Pacific 137Cs labeled waters to the south-eastern Atlantic Ocean

    Science.gov (United States)

    Sanchez-Cabeza, J. A.; Levy, I.; Gastaud, J.; Eriksson, M.; Osvath, I.; Aoyama, M.; Povinec, P. P.; Komura, K.

    2011-04-01

    During the reoccupation of the WOCE transect A10 at 30°S by the BEAGLE2003 cruise, the SHOTS project partners collected a large number of samples for the analysis of isotopic tracers. 137Cs was mostly deposited on the oceans surface during the late 1950s and early 1960s, after the atmospheric detonation of large nuclear devices, which mostly occurred in the Northern Hemisphere. The development of advanced radioanalytical and counting techniques allowed to obtain, for the first time in this region, a zonal section of 137Cs water concentrations, where little information existed before, thus constituting an important benchmark for further studies. 137Cs concentrations in the upper waters (0-1000 m) of the south-eastern Atlantic Ocean are similar to those observed in the south-western Indian Ocean, suggesting transport of 137Cs labeled waters by the Agulhas current to the Benguela Current region. In contrast, bomb radiocarbon data do not show this feature, indicating the usefulness of 137Cs as a radiotracer of water mass transport from the Indian to the South Atlantic Ocean.

  1. Fatty acids as biomarkers for food web structure in the eastern North Pacific Ocean

    Science.gov (United States)

    Behrens, J.; Aluwihare, L.; Stephens, B. M.

    2015-12-01

    Resulting from a NSF funded REU program at Scripps Institution of Oceanography in 2015, this research utilized gas chromatography-mass spectrometry (GC-MS) to analyze the fatty acid composition of suspended particulate organic matter (POM) and zooplankton (ZP; primarily copepods). Samples analyzed for this study were collected simultaneously from surface waters approximately 9 miles off the coast of San Diego in June 2015. I was testing the hypothesis that essential fatty acids in ZP should reflect their diet, in particular, distinguishing contributions from a microbial versus traditional food web. Food web structure in this region of the ocean has been shown to be sensitive to climate change on inter-annual and longer timescales. Thus, a proxy that identifies restructuring of food webs would be useful for examining the response of ocean ecosystems to future climate change. Lipids were extracted from ZP and POM using a modified Bligh and Dyer method with sonication. Following saponification free fatty acids and other lipids were further purified using column chromatography. Polar functional groups in lipids were then methylated prior to GC-MS analysis. In addition, 2-dimensional GCxGC with time of flight MS was used to distinguish polyunsaturated fatty acid isomers. My poster will present initial findings of shared fatty acids of zooplankton and POM suspended material from the Northern Pacific collection site. Further research will be focused on analyzing the hydrogen isotope composition of fatty acids in zooplankton and suspended DOM obtained at the collection site to further characterize and increase certainty on the role of microbes and phytoplankton in the region's food-web to distinguish prokaryotic and eukaryotic sources.

  2. Observations of heterogeneous reactions between Asian pollution and mineral dust over the Eastern North Pacific during INTEX-B

    Directory of Open Access Journals (Sweden)

    F. Flocke

    2009-11-01

    Full Text Available In-situ airborne measurements of trace gases, aerosol size distributions, chemistry and optical properties were conducted over Mexico and the Eastern North Pacific during MILAGRO and INTEX-B. Heterogeneous reactions between secondary aerosol precursor gases and mineral dust lead to sequestration of sulfur, nitrogen and chlorine in the supermicrometer particulate size range.

    Simultaneous measurements of aerosol size distributions and weak-acid soluble calcium result in an estimate of 11 wt% of CaCO3 for Asian dust. During transport across the North Pacific, ~5–30% of the CaCO3 is converted to CaSO4 or Ca(NO32 with an additional ~4% consumed through reactions with HCl. The 1996 to 2008 record from the Mauna Loa Observatory confirm these findings, indicating that, on average, 19% of the CaCO3 has reacted to form CaSO4 and 7% has reacted to form Ca(NO32 and ~2% has reacted with HCl. In the nitrogen-oxide rich boundary layer near Mexico City up to 30% of the CaCO3 has reacted to form Ca(NO32 while an additional 8% has reacted with HCl.

    These heterogeneous reactions can result in a ~3% increase in dust solubility which has an insignificant effect on their optical properties compared to their variability in-situ. However, competition between supermicrometer dust and submicrometer primary aerosol for condensing secondary aerosol species led to a 25% smaller number median diameter for the accumulation mode aerosol. A 10–25% reduction of accumulation mode number median diameter results in a 30–70% reduction in submicrometer light scattering at relative humidities in the 80–95% range. At 80% RH submicrometer light scattering is only reduced ~3% due to a higher mass fraction of hydrophobic refractory components in the dust-affected accumulation mode aerosol. Thus reducing the geometric mean diameter of

  3. Nitrogen and oxygen isotopic composition of N sub(2)O from suboxic waters of the eastern tropical North Pacific and the Arabian Sea - measurement by continuous-flow isotope-ratio monitoring

    Digital Repository Service at National Institute of Oceanography (India)

    Yoshinari, T.; Altabet, M.A.; Naqvi, S.W.A.; Codispoti, L.; Jayakumar, D.A.; Kuhland, M.; Devol, A.

    and of the dual stable isotopic composition of N sub(2)O in the eastern tropical North Pacific (ETNP) and the Arabian Sea. The stable isotopic composition of N sub(2)O was determined by a new method that required only 80-100 nmol of N sub(2)O per sample analysis...

  4. Investigations of (Delta)14C, (delta)13C, and (delta)15N in vertebrae of white shark (Carcharodon carcharias) from the eastern North Pacific Ocean

    Energy Technology Data Exchange (ETDEWEB)

    Kerr, L A; Andrews, A H; Cailliet, G M; Brown, T A; Coale, K H

    2006-06-08

    The white shark (Carcharodon carcharias) has a complex life history that is characterized by large scale movements and a highly variable diet. Estimates of age and growth for the white shark from the eastern North Pacific Ocean indicate they have a slow growth rate and a relatively high longevity. Age, growth, and longevity estimates useful for stock assessment and fishery models, however, require some form of validation. By counting vertebral growth band pairs, ages can be estimated, but because not all sharks deposit annual growth bands and many are not easily discernable, it is necessary to validate growth band periodicity with an independent method. Radiocarbon ({sup 14}C) age validation uses the discrete {sup 14}C signal produced from thermonuclear testing in the 1950s and 1960s that is retained in skeletal structures as a time-specific marker. Growth band pairs in vertebrae, estimated as annual and spanning the 1930s to 1990s, were analyzed for {Delta}{sup 14}C and stable carbon and nitrogen isotopes ({delta}{sup 13}C and {delta}{sup 15}N). The aim of this study was to evaluate the utility of {sup 14}C age validation for a wide-ranging species with a complex life history and to use stable isotope measurements in vertebrae as a means of resolving complexity introduced into the {sup 14}C chronology by ontogenetic shifts in diet and habitat. Stable isotopes provided useful trophic position information; however, validation of age estimates was confounded by what may have been some combination of the dietary source of carbon to the vertebrae, large-scale movement patterns, and steep {sup 14}C gradients with depth in the eastern North Pacific Ocean.

  5. Interannual variability of western North Pacific SST anomalies and its impact on North Pacific and North America

    Science.gov (United States)

    Park, Jae-Heung; An, Soon-Il; Kug, Jong-Seong

    2017-02-01

    In this study, the interannual variability of sea surface temperature (SST) and its atmospheric teleconnection over the western North Pacific (WNP) toward the North Pacific/North America during boreal winter are investigated. First, we defined the WNP mode as the first empirical orthogonal function (EOF) mode of SST anomalies over the WNP region (100-165°E, 0-35°N), of which the principle component time-series are significantly correlated with several well-known climate modes such as the warm pool mode which is the second EOF mode of the tropical to North Pacific SST anomalies, North Pacific oscillation (NPO), North Pacific gyre oscillation (NPGO), and central Pacific (CP)-El Niño at 95% confidence level, but not correlated with the eastern Pacific (EP)-El Niño. The warm phase of the WNP mode (sea surface warming) is initiated by anomalous southerly winds through reduction of wind speed with the background of northerly mean winds over the WNP during boreal winter, i.e., reduced evaporative cooling. Meanwhile, the atmospheric response to the SST warming pattern and its diabatic heating further enhance the southerly wind anomaly, referred to the wind-evaporation-SST (WES) feedback. Thus, the WNP mode is developed and maintained through winter until spring, when the northerly mean wind disappears. Furthermore, it is also known that anomalous upper-level divergence associated with WNP mode leads to the NPO-like structure over the North Pacific and the east-west pressure contrast pattern over the North America through Rossby wave propagation, impacting the climate over the North Pacific and North America.

  6. Determining bathymetric distributions of the eelgrass Zostera marina L. in three turbid estuaries of the eastern North Pacific coast

    Science.gov (United States)

    Improved methods for determining bathymetric distributions of dominant intertidal plants throughout their estuarine range are needed. Zostera marina is a seagrass native to estuaries of the northeastern Pacific and many other sectors of the world ocean. The technique described ...

  7. Southern Ocean influence on the eastern tropical North Pacific's intermediate-depth circulation during the Last Glacial Maximum

    OpenAIRE

    Carriquiry, José; Sanchez, Alberto; Leduc, Guillaume

    2015-01-01

    International audience; The oxygen and carbon isotopic compositions of benthic foraminiferal tests were measured on sedimentary sequences retrieved on the Magdalena Margin, off southern Baja California, Mexico. We reconstruct the hydrographic changes along the water column that occurred in the northeastern tropical Pacific since the Last Glacial Maximum (LGM) and compare those changes to the ones that occurred in the northwest Pacific (NWP, i.e., off Japan and Russia), in the northeast Pacifi...

  8. Decadal to centennial fluctuations in the intensity of the eastern tropical North Pacific oxygen minimum zone during the last 1200 years

    Science.gov (United States)

    Tems, Caitlin E.; Berelson, William M.; Thunell, Robert; Tappa, Eric; Xu, Xiaomei; Khider, Deborah; Lund, Steve; González-Yajimovich, Oscar; Hamann, Yvonne

    2016-08-01

    Oxygen minimum zones (OMZs), located below highly productive marine regions, are sites of microbially mediated denitrification and biogeochemical cycling that have global significance. The intensity of OMZs fluctuates naturally; however, the degree of these fluctuations and a comprehensive understanding of the factors that drive these fluctuations on decadal to centennial time scales is lacking. Our high-resolution (near-annual) record of δ15Nsed from laminated sediments at the Pescadero Slope in the Gulf of California (eastern tropical North Pacific) fluctuates between maximum values of 10.5‰ and minimum values of 8.0‰ over the past 1200 years. An analysis of the relationship between δ15NO3- and [O2] in the water column suggests that the observed range of δ15Nsed values is equivalent to an approximately 8 µM fluctuation in O2 content and that these changes can occur in less than 25 years. Our findings show that the OMZ typically intensifies quickly and contracts gradually; the average rate of OMZ intensification (-0.24 µM O2/yr) is twice as fast as the rate of OMZ reoxygenation. Spectral analyses of the δ15Nsed record and Br/Cl counts, with the latter are used as a proxy for organic carbon preservation, suggest that the Pacific Decadal Oscillation and the Suess (deVries) solar cycle (solar irradiance) may influence the intensity of the OMZ and carbon production/export during the late Holocene. Coherence between δ15Nsed and weight percent organic carbon also suggests that similar mechanisms influence both OMZ fluctuations and variation in organic carbon production/export.

  9. Intact polar lipids of Thaumarchaeota and anammox bacteria as indicators of N-cycling in the Eastern Tropical North Pacific oxygen deficient zone

    Directory of Open Access Journals (Sweden)

    M. Sollai

    2015-03-01

    Full Text Available In the last decade our understanding of the marine nitrogen cycle has improved considerably thanks to the discovery of two novel groups of microorganisms: ammonia-oxidizing archaea (AOA and anaerobic ammonia-oxidizing (anammox bacteria. Both groups are important in oxygen deficient zones (ODZs, where they substantially affect the marine N-budget. These two groups of microbes are also well known for producing specific membrane lipids, which can be used as biomarkers to trace their presence in the environment. We investigated the occurrence and distribution of AOA and anammox bacteria in the water column of the Eastern Tropical North Pacific (ETNP ODZ, one of the most prominent ODZs worldwide. Suspended particulate matter (SPM was collected at different depths of the water column in high resolution, at both a coastal and an open ocean setting. The SPM was analyzed for AOA- and anammox bacteria-specific intact polar lipids (IPLs, i.e. hexose-phosphohexose (HPH-crenarchaeol and phosphatidylcholine (PC-monoether ladderane. Comparison with oxygen profiles reveals that both the microbial groups are able to thrive at low (<1 μM concentrations of oxygen. Our results indicate a clear niche segregation of AOA and anammox bacteria in the coastal waters of the ETNP, but a partial overlap of the two niches of these microbial species in the open water setting. The latter distribution suggests the potential for an interaction between the two microbial groups at the open ocean site, either as competition or cooperation.

  10. Eastern Pacific Ocean Purse-seine Fishery

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vessel logbook and landings data sets from U.S.A.-flagged purse-seine vessels fishing in the Eastern Pacific Ocean (EPO). These purse seiners...

  11. Organic composition of single and submicron particles in different regions of western North America and the eastern Pacific during INTEX-B 2006

    Directory of Open Access Journals (Sweden)

    D. A. Day

    2009-08-01

    Full Text Available Single particles were collected from an aircraft platform as part of the Intercontinental Chemical Transport Experiment – Phase B (INTEX-B conducted over the eastern Pacific and western North America. Single particle spectra were obtained using scanning transmission X-ray microscopy-near edge X-ray absorption fine structure spectroscopy (STXM-NEXAFS. Bulk submicron particles were also collected and organic functional group and elemental concentrations were quantified with Fourier transform infrared (FTIR spectroscopy and X-ray fluorescence (XRF. Single particle spectra were classified into metaclasses associated with different sources and atmospheric processing. Particles with spectra indicative of secondary organic aerosol production and combustion sources were found at several locations and a range of altitudes. At lower altitudes, particles with spectra resembling soil dust and biomass burning fingerprints were commonly observed. The types of particle spectra most commonly observed aloft were similar to those observed during a previous study over the northwestern Pacific, indicating that long-range transport may have been an important particle source. Single particle spectra provided evidence that condensation and surface-limited oxidation contributed to particle growth. Organic mass (OM concentrations ranged from 1 to 7 μg m−3 and averaged 2.4–4.1 μg m−3. Alkane functional groups were the largest fraction of OM, averaging 1.9–2.1 μg m−3 or 50–76% of OM, followed by alcohol functional groups (0.35–0.39 μg m−3, 9–14%. Organic and elemental concentrations are compared within and among geographical air mass regions: "Pacific" free troposphere, "Continental" free troposphere, "Seattle" metropolitan region, and the California "Central Valley". OM concentrations were highest and most variable in the Central Valley (3.5±2 μg m−3. Oxygen-to-carbon ratios were

  12. North Pacific Pelagic Seabird Database (NPPSD)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The North Pacific Pelagic Seabird Database (NPPSD) was created in 2005 to consolidate data on the oceanic distribution of marine bird species in the North Pacific....

  13. On North Pacific circulation and associated marine debris concentration.

    Science.gov (United States)

    Howell, Evan A; Bograd, Steven J; Morishige, Carey; Seki, Michael P; Polovina, Jeffrey J

    2012-01-01

    Marine debris in the oceanic realm is an ecological concern, and many forms of marine debris negatively affect marine life. Previous observations and modeling results suggest that marine debris occurs in greater concentrations within specific regions in the North Pacific Ocean, such as the Subtropical Convergence Zone and eastern and western "Garbage Patches". Here we review the major circulation patterns and oceanographic convergence zones in the North Pacific, and discuss logical mechanisms for regional marine debris concentration, transport, and retention. We also present examples of meso- and large-scale spatial variability in the North Pacific, and discuss their relationship to marine debris concentration. These include mesoscale features such as eddy fields in the Subtropical Frontal Zone and the Kuroshio Extension Recirculation Gyre, and interannual to decadal climate events such as El Niño and the Pacific Decadal Oscillation/North Pacific Gyre Oscillation. Published by Elsevier Ltd.

  14. Primary production in the eastern tropical Pacific: A review

    Science.gov (United States)

    Pennington, J. Timothy; Mahoney, Kevin L.; Kuwahara, Victor S.; Kolber, Dorota D.; Calienes, Ruth; Chavez, Francisco P.

    2006-05-01

    The eastern tropical Pacific includes 28 million km 2 of ocean between 23.5°N and S and Central/South America and 140°W, and contains the eastern and equatorial branches of the north and South Pacific subtropical gyres plus two equatorial and two coastal countercurrents. Spatial patterns of primary production are in general determined by supply of macronutrients (nitrate, phosphate) from below the thermocline. Where the thermocline is shallow and intersects the lighted euphotic zone, biological production is enhanced. In the eastern tropical Pacific thermocline depth is controlled by three interrelated processes: a basin-scale east/west thermocline tilt, a basin-scale thermocline shoaling at the gyre margins, and local wind-driven upwelling. These processes regulate supply of nutrient-rich subsurface waters to the euphotic zone, and on their basis we have divided the eastern tropical Pacific into seven main regions. Primary production and its physical and chemical controls are described for each. Enhanced rates of macronutrient supply maintains levels of primary production in the eastern tropical Pacific above those of the oligotrophic subtropical gyres to the north and south. On the other hand lack of the micronutrient iron limits phytoplankton growth (and nitrogen fixation) over large portions of the open-ocean eastern tropical Pacific, depressing rates of primary production and resulting in the so-called high nitrate-low chlorophyll condition. Very high rates of primary production can occur in those coastal areas where both macronutrients and iron are supplied in abundance to surface waters. In these eutrophic coastal areas large phytoplankton cells dominate; conversely, in the open-ocean small cells are dominant. In a ‘shadow zone’ between the subtropical gyres with limited subsurface ventilation, enough production sinks and decays to produce anoxic and denitrified waters which spread beneath very large parts of the eastern tropical Pacific. Seasonal

  15. Conservation of North Pacific shorebirds

    Science.gov (United States)

    Gill, Robert E.; Butler, Robert W.; Tomkovich, Pavel S.; Mundkur, Taej; Handel, Colleen M.

    1994-01-01

    In his introduction to the 1979 Symposium proceedings entitled “Shorebirds in Marine Environments," Frank Pitelka stressed the need for studies and conservation programs that spanned the western hemisphere (Pitelka 1979). In the 15 years since Pitelka's call to arms, the locations of many important migratory and wintering sites for shorebirds have been identified in the Americas (Senner and Howe 1984, Morrison and Ross 1989, Morrison and Butler 1994) and in the East Asian-Australasian flyway (Lane and Parish 1991, Mundkur 1993, Watkins 1993). However, assessments for Central America, the Russian Far East and most of Oceania remain incomplete or lacking.The recognition that shorebird conservation required the protection of habitats throughout the birds' range (e.g., Morrison 1984, Davidson and Evans 1989 in Ens et al. 1990) prompted the establishment of the Western Hemisphere Shorebird Reserve Network (WHSRN) in the Americas in 1985 (Joyce 1986). This program complemented the 1971 Convention on Wetlands of International Importance Especially for Waterbirds (Ramsar Convention, Smart 1987), recognized by more that 50 countries world-wide.Our purpose for writing this paper is to: (1) describe the distribution of North Pacific shorebirds throughout their annual cycle; (2) review the locations of and threats to important sites used by North Pacific shorebirds during the breeding, migration, and wintering periods, and (3) outline a program for international conservation of Pacific shorebirds.

  16. {sup 137}Cs, {sup 239+240}Pu and {sup 240}Pu/{sup 239}Pu atom ratios in the surface waters of the western North Pacific Ocean, eastern Indian Ocean and their adjacent seas

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Masatoshi; Zheng, Jian; Wang, Zhong-Liang [Nakaminato Laboratory for Marine Radioecology, National Institute of Radiological Sciences, Isozaki 3609, Hitachinaka, Ibaraki 311-1202 (Japan)

    2006-07-31

    Surface seawater samples were collected along the track of the R/V Hakuho-Maru cruise (KH-96-5) from Tokyo to the Southern Ocean. The {sup 137}Cs activities were determined for the surface waters in the western North Pacific Ocean, the Sulu and Indonesian Seas, the eastern Indian Ocean, the Bay of Bengal, the Andaman Sea, and the South China Sea. The {sup 137}Cs activities showed a wide variation with values ranging from 1.1 Bq m{sup -3} in the Antarctic Circumpolar Region of the Southern Ocean to 3 Bq m{sup -3} in the western North Pacific Ocean and the South China Sea. The latitudinal distributions of {sup 137}Cs activity were not reflective of that of the integrated deposition density of atmospheric global fallout. The removal rates of {sup 137}Cs from the surface waters were roughly estimated from the two data sets of Miyake et al. [Miyake Y, Saruhashi K, Sugimura Y, Kanazawa T, Hirose K. Contents of {sup 137}Cs, plutonium and americium isotopes in the Southern Ocean waters. Pap Meteorol Geophys 1988;39:95-113] and this study to be 0.016 yr{sup -1} in the Sulu and Indonesian Seas, 0.033 yr{sup -1} in the Bay of Bengal and Andaman Sea, and 0.029 yr{sup -1} in the South China Sea. These values were much lower than that in the coastal surface water of the western Northwest Pacific Ocean. This was likely due to less horizontal and vertical mixing of water masses and less scavenging. {sup 239+240}Pu activities and {sup 240}Pu/{sup 239}Pu atom ratios were also determined for the surface waters in the western North Pacific Ocean, the Sulu and Indonesian Seas and the South China Sea. The {sup 240}Pu/{sup 239}Pu atom ratios ranged from 0.199+/-0.026 to 0.248+/-0.027 on average, and were significantly higher than the global stratospheric fallout ratio of 0.18. The contributions of the North Pacific Proving Grounds close-in fallout Pu were estimated to be 20% for the western North Pacific Ocean, 39% for the Sulu and Indonesian Seas and 42% for the South China Sea by using

  17. {sup 137}Cs, {sup 239+24}Pu and {sup 24}Pu/{sup 239}Pu atom ratios in the surface waters of the western North Pacific Ocean, eastern Indian Ocean and their adjacent seas

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Masatoshi [Nakaminato Laboratory for Marine Radioecology, National Institute of Radiological Sciences, Isozaki 3609, Hitachinaka, Ibaraki 311-1202 (Japan)]. E-mail: m_yamada@nirs.go.jp; Zheng Jian [Nakaminato Laboratory for Marine Radioecology, National Institute of Radiological Sciences, Isozaki 3609, Hitachinaka, Ibaraki 311-1202 (Japan); Wang Zhongliang [Nakaminato Laboratory for Marine Radioecology, National Institute of Radiological Sciences, Isozaki 3609, Hitachinaka, Ibaraki 311-1202 (Japan); State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guanshui Road 46, Guiyang 550002 (China)

    2006-07-31

    Surface seawater samples were collected along the track of the R/V Hakuho-Maru cruise (KH-96-5) from Tokyo to the Southern Ocean. The {sup 137}Cs activities were determined for the surface waters in the western North Pacific Ocean, the Sulu and Indonesian Seas, the eastern Indian Ocean, the Bay of Bengal, the Andaman Sea, and the South China Sea. The {sup 137}Cs activities showed a wide variation with values ranging from 1.1 Bq m{sup -3} in the Antarctic Circumpolar Region of the Southern Ocean to 3 Bq m{sup -3} in the western North Pacific Ocean and the South China Sea. The latitudinal distributions of {sup 137}Cs activity were not reflective of that of the integrated deposition density of atmospheric global fallout. The removal rates of {sup 137}Cs from the surface waters were roughly estimated from the two data sets of Miyake et al. [Miyake Y, Saruhashi K, Sugimura Y, Kanazawa T, Hirose K. Contents of {sup 137}Cs, plutonium and americium isotopes in the Southern Ocean waters. Pap Meteorol Geophys 1988;39:95-113] and this study to be 0.016 yr{sup -1} in the Sulu and Indonesian Seas, 0.033 yr{sup -1} in the Bay of Bengal and Andaman Sea, and 0.029 yr{sup -1} in the South China Sea. These values were much lower than that in the coastal surface water of the western Northwest Pacific Ocean. This was likely due to less horizontal and vertical mixing of water masses and less scavenging. {sup 239+24}Pu activities and {sup 24}Pu/{sup 239}Pu atom ratios were also determined for the surface waters in the western North Pacific Ocean, the Sulu and Indonesian Seas and the South China Sea. The {sup 24}Pu / {sup 239}Pu atom ratios ranged from 0.199 {+-} 0.026 to 0.248 {+-} 0.027 on average, and were significantly higher than the global stratospheric fallout ratio of 0.18. The contributions of the North Pacific Proving Grounds close-in fallout Pu were estimated to be 20% for the western North Pacific Ocean, 39% for the Sulu and Indonesian Seas and 42% for the South China Sea by

  18. Requiem for an eastern Pacific seagrass bed.

    Science.gov (United States)

    Cortés, J

    2001-12-01

    Few papers concerning seagrasses of the eastern Pacific have been published. This paper presents the first ecological data on the seagrass, Ruppia maritima, from a non-lagoonal setting in the eastern Pacific. A 5000 m2 patch formed by R. maritima, at Playa Iguanita, Bahía Culebra, Pacific coast of Costa Rica was studied. Plant density and leaf length of R. maritima were determined along two transects on different dates. Above and below ground biomass were calculated along one transect. Plant density ranged from 1590 to 8630 individuals m(-2) along the two transects, with means of 5990 +/- 1636 and 6100 +/- 1876 plants m(-2) for transect 1 and 2, respectively. Longest leaf length per plant varied between 0.5 and 23.0 cm. Leaf biomass (LB) ranged from 10 to 97 gm(-2), and root-rhizome biomass (RB) from 31 to 411 gm(-2), resulting in RB:LB ratios of 3.07 to 15.27. Total biomass at Bahía Culebra was lower than at tropical lagoons on the Pacific coast of Mexico, but higher than in the Gulf of Mexico. The below ground: above ground biomass ratio was much higher at Bahía Culebra than at other sites on the Pacific coast of Mexico and the Gulf of Mexico. Another seagrass present at Bahía Culebra was Halophila baillonii, with low densities on the deepest section of the patch. At least 44 invertebrate species associated with the seagrass bed have also been identified. The patch at Playa Iguanita and other sites within Bahía Culebra, as well as their associated organisms, disappeared after a severe storm in June 1996. No seagrasses have been found in the area or in any other location on the Pacific coast of Costa Rica since then.

  19. AFSC/NMML: North Pacific Right Whale Photo-ID Catalog

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The eastern population of the North Pacific right whale (Eubalaena japonica) is the most endangered stock of whales in the world, with recent abundance estimates...

  20. Albatross species demonstrate regional differences in North Pacific marine contamination.

    Science.gov (United States)

    Finkelstein, Myra; Keitt, Bradford S; Croll, Donald A; Tershy, Bernie; Jarman, Walter M; Rodriguez-Pastor, Sue; Anderson, David J; Sievert, Paul R; Smith, Donald R

    2006-04-01

    Recent concern about negative effects on human health from elevated organochlorine and mercury concentrations in marine foods has highlighted the need to understand temporal and spatial patterns of marine pollution. Seabirds, long-lived pelagic predators with wide foraging ranges, can be used as indicators of regional contaminant patterns across large temporal and spatial scales. Here we evaluate contaminant levels, carbon and nitrogen stable isotope ratios, and satellite telemetry data from two sympatrically breeding North Pacific albatross species to demonstrate that (1) organochlorine and mercury contaminant levels are significantly higher in the California Current compared to levels in the high-latitude North Pacific and (2) levels of organochlorine contaminants in the North Pacific are increasing over time. Black-footed Albatrosses (Phoebastria nigripes) had 370-460% higher organochlorine (polychlorinated biphenyls [PCBs], dichlorodiphenyltrichloroethanes [DDTs]) and mercury body burdens than a closely related species, the Laysan Albatross (P. immutabilis), primarily due to regional segregation of their North Pacific foraging areas. PCBs (the sum of the individual PCB congeners analyzed) and DDE concentrations in both albatross species were 130-360% higher than concentrations measured a decade ago. Our results demonstrate dramatically high and increasing contaminant concentrations in the eastern North Pacific Ocean, a finding relevant to other marine predators, including humans.

  1. Legacy and contemporary persistent organic pollutants in North Pacific albatross.

    Science.gov (United States)

    Harwani, Suhash; Henry, Robert W; Rhee, Alexandra; Kappes, Michelle A; Croll, Donald A; Petreas, Myrto; Park, June-Soo

    2011-11-01

    Here we report the first measurements of polybrominated diphenyl ethers (PBDE 47, 99, and 153) alongside 11 organochlorine pesticides (OCPs) and 28 polychlorinated biphenyls (PCBs) in the plasma of albatross from breeding colonies distributed across a large spatial east-west gradient in the North Pacific Ocean. North Pacific albatross are wide-ranging, top-level consumers that forage in pelagic regions of the North Pacific Ocean, making them an ideal sentinel species for detection and distribution of marine contaminants. Our work on contaminant burdens in albatross tissue provides information on transport of persistent organic pollutants (POPs) to the remote North Pacific and serves as a proxy for regional environmental quality. We sampled black-footed (Phoebastria nigripes; n = 20) and Laysan albatross (P. immutabilis; n = 19) nesting on Tern Island, Hawaii, USA, and Laysan albatross (n = 16) nesting on Guadalupe Island, Mexico. Our results indicate that North Pacific albatross are highly exposed to both PCBs and OCPs, with levels ranging from 8.8 to 86.9 ng/ml wet weight and 7.4 to 162.3 ng/ml wet weight, respectively. A strong significant gradient exists between Laysan albatross breeding in the Eastern Pacific, having approximately 1.5-fold and 2.5-fold higher levels for PCBs and OCPs, respectively, compared to those from the Central Pacific. Interspecies levels of contaminants within the same breeding site also showed high variation, with Tern black-footed albatross having approximately threefold higher levels of both PCBs and OCPs than Tern Laysan albatross. Surprisingly, while PBDEs are known to travel long distances and bioaccumulate in wildlife of high trophic status, we detected these three PBDE congeners only at trace levels ranging from not detectable (ND) to 0.74 ng/ml wet weight in these albatross. Copyright © 2011 SETAC.

  2. Ecological patterns, distribution and population structure of Prionace glauca (Chondrichthyes: Carcharhinidae) in the tropical-subtropical transition zone of the north-eastern Pacific.

    Science.gov (United States)

    Vögler, Rodolfo; Beier, Emilio; Ortega-García, Sofía; Santana-Hernández, Heriberto; Valdez-Flores, J Javier

    2012-02-01

    Regional ecological patterns, distribution and population structure of Prionace glauca were analyzed based on samples collected on-board two long-line fleets operating in oceanic waters (1994-96/2000-02) and in coastal oceanic waters (2003-2009) of the eastern tropical Pacific off México. Generalized additive models were applied to catch per unit of effort data to evaluate the effect of spatial, temporal and environmental factors on the horizontal distribution of the life stages (juvenile, adult) and the sexes at the estimated depth of catch. The presence of breeding areas was explored. The population structure was characterized by the presence of juveniles' aggregations and pregnant females towards coastal waters and the presence of adult males' aggregations towards oceanic waters. The species exhibited horizontal segregation by sex-size and vertical segregation by sex. Distribution of the sex-size groups at oceanic waters was seasonally affected by the latitude; however, at coastal oceanic waters mainly females were influenced by the longitude. Latitudinal changes on the horizontal distribution were coupled to the seasonal forward and backward of water masses through the study area. Adult males showed positive relationship with high temperatures and high-salinities waters (17.0°-20.0 °C; 34.2-34.4) although they were also detected in low-salinities waters. The distribution of juvenile males mainly occurred beyond low temperatures and low-salinities waters (14.0°-15.0 °C; 33.6-34.1), suggesting a wide tolerance of adult males to explore subartic and subtropical waters. At oceanic areas, adult females were aggregated towards latitudes glauca. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Expedition surveys of the sea water and atmospheric air radioactive contamination in the Russian Far Eastern coastal areas and in the North Western Pacific in connection with accident at the "Fukushima-1" NPP

    Science.gov (United States)

    Nikitin, Aleksandr; Shershakov, Vjacheslav

    2013-04-01

    In accordance with decision of the Russian Federation Federal Service on Hydrometeorology and Environmental Monitoring (Roshydromet) on assessment of the sea water and atmospheric air radioactive contamination in the Sea of Japan and in Kurile-Kamchatka region of the Pacific ocean, in connection with accident at the "Fukushima-1" NPP, two expedition surveys were conducted in the Sea of Japan and in the North-Western Pacific (in the area adjacent to Kurile Islands and in the Kuroshio current selected area (coordinates 36°00'-39°33' n., 146°33'-150°00' e.): first survey April - May 2011, second survey August-September 2012. Both surveys were conducted under the Russian Geographical Society patronage. The results of measurements of Cs-137, Cs-134, Sr-90, Pu-239,240 and H-3 concentrations in the sea water samples and I-131, Cs-137 and Cs-134 concentrations in atmospheric aerosol samples are presented and discussed. The data received allowed to conclude that the levels of contamination by products of accidental releases and discharges at "Fukushima-1" NPP observed in investigated water areas near the Russian Federation coast of the Sea of Japan and of the Kurile- Kamchatka region of the Pacific ocean have no hazard. However, these expedition surveys revealed large-scale contamination by Cs-137 and Cs-134 of water areas of the North-Western Pacific in the investigated region of the Kuroshio current. The Cs-137 concentration in sea water at a distance about 400 km from accidental NPP in April-May, 2011 reached 30 Bq/m3, which approximately 20 times exceed preaccidental level, and it was found that water mass till more than 100 m below the surface was contaminated. For correct estimation of current and potential consequences of the "Fukushima-1" accident for the Far-Eastern water areas a special study is reasonable to perform of transport with marine currents of products of accidental releases and discharges at "Fukushima-1" NPP.

  4. Eastern Pacific tropical cyclones intensified by El Niño delivery of subsurface ocean heat.

    Science.gov (United States)

    Jin, F-F; Boucharel, J; Lin, I-I

    2014-12-04

    The El Niño Southern Oscillation (ENSO) creates strong variations in sea surface temperature in the eastern equatorial Pacific, leading to major climatic and societal impacts. In particular, ENSO influences the yearly variations of tropical cyclone (TC) activities in both the Pacific and Atlantic basins through atmospheric dynamical factors such as vertical wind shear and stability. Until recently, however, the direct ocean thermal control of ENSO on TCs has not been taken into consideration because of an apparent mismatch in both timing and location: ENSO peaks in winter and its surface warming occurs mostly along the Equator, a region without TC activity. Here we show that El Niño--the warm phase of an ENSO cycle--effectively discharges heat into the eastern North Pacific basin two to three seasons after its wintertime peak, leading to intensified TCs. This basin is characterized by abundant TC activity and is the second most active TC region in the world. As a result of the time involved in ocean transport, El Niño's equatorial subsurface 'heat reservoir', built up in boreal winter, appears in the eastern North Pacific several months later during peak TC season (boreal summer and autumn). By means of this delayed ocean transport mechanism, ENSO provides an additional heat supply favourable for the formation of strong hurricanes. This thermal control on intense TC variability has significant implications for seasonal predictions and long-term projections of TC activity over the eastern North Pacific.

  5. The circulation of the eastern tropical Pacific: A review

    Science.gov (United States)

    Kessler, William S.

    2006-05-01

    During the 1950s and 1960s, an extensive field study and interpretive effort was made by researchers, primarily at the Scripps Institution of Oceanography, to sample and understand the physical oceanography of the eastern tropical Pacific. That work was inspired by the valuable fisheries of the region, the recent discovery of the equatorial undercurrent, and the growing realization of the importance of the El Niño phenomenon. Here we review what was learned in that effort, and integrate those findings with work published since then as well as additional diagnoses based on modern data sets. Unlike the central Pacific, where the winds are nearly zonal and the ocean properties and circulation are nearly independent of longitude, the eastern tropical Pacific is distinguished by wind forcing that is strongly influenced by the topography of the American continent. Its circulation is characterized by short zonal scales, permanent eddies and significant off-equatorial upwelling. Notably, the Costa Rica Dome and a thermocline bowl to its northwest are due to winds blowing through gaps in the Central American cordillera, which imprint their signatures on the ocean through linear Sverdrup dynamics. Strong annual modulation of the gap winds and the meridional oscillation of the Intertropical Convergence Zone generates a Rossby wave, superimposed on the direct forcing, that results in a southwestward-propagating annual thermocline signal accounting for major features of observed thermocline depth variations, including that of the Costa Rica Dome, the Tehuantepec bowl, and the ridge-trough system of the North Equatorial Countercurrent (NECC). Interannual variability of sea surface temperature (SST) and altimetric sea surface height signals suggests that the strengthening of the NECC observed in the central Pacific during El Niño events continues all the way to the coast, warming SST (by zonal advection) in a wider meridional band than the equatorially trapped thermocline

  6. Observations of carbon dioxide in the surface waters of the Eastern North Pacific Ocean and the Bering Sea from 21 July 1968 to 03 September 1968 (NODC Accession 7100114)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Measurements of the equilibrium concentration of carbon dioxide in the air and surface waters of the North Pacific Ocean and the Bering Sea are presented....

  7. Geological history of the Western north pacific.

    Science.gov (United States)

    Fischer, A G; Heezen, B C; Boyce, R E; Bury, D; Douglas, R G; Garrison, R E; Kling, S A; Krasheninnikov, V; Lisitzin, A P; Pimm, A C

    1970-06-05

    A considerable portion of the abyssal floor of the western North Pacific was already receiving pelagic sediment in late Jurassic time. Carbonate sediments were later replaced by abyssal clays as the basin deepened and bottom waters became more aggressive. The resulting facies boundary, which can be recognized on seismic profiles, is broadly transgressive; it ranges in age from mid-Cretaceous in the western Pacific to Oligocene in the central Pacific. Cherts are encountered at and below the major facies boundary and appear to have been formed by postdepositional processes.

  8. Silicon stable isotope distribution traces Southern Ocean export of Si to the eastern South Pacific thermocline

    Science.gov (United States)

    de Souza, G. F.; Reynolds, B. C.; Johnson, G. C.; Bullister, J. L.; Bourdon, B.

    2012-11-01

    The cycling and transport of dissolved silicon (Si) in the ocean may be traced by its stable isotope composition, δ30Si. We present a dataset of δ30Si values along 103° W in the eastern South Pacific Ocean, ranging from the Antarctic Zone of the Southern Ocean (62° S) to the equatorial Pacific (12° S). At high southern latitudes, the uptake and associated isotope fractionation of Si by diatoms results in highly elevated δ30Si values (up to +3.2‰) in the summer mixed layer. High δ30Si values (+2‰) are also preserved in the high-latitude fossil winter mixed layer, documenting the efficient export of diatom opal beyond the maximum depth of winter convection. This elevated winter mixed layer δ30Si signature is introduced into the ocean interior by the subduction of Subantarctic Mode Water (SAMW) and Antarctic Intermediate Water (AAIW), whose northward spreading results in a strong isopycnal control on lower-thermocline and intermediate δ30Si values in the well-ventilated eastern South Pacific. Values of δ30Si are strongly conserved along SAMW and AAIW density levels as far north as 26° S, documenting the importance of the export of preformed Si from the surface Southern Ocean to lower latitudes. In contrast, in the equatorial Pacific, depressed δ30Si values in the mesopelagic ocean are observed, most likely documenting the combined influence of a North Pacific Si source as well as the accumulation of remineralized Si within the eastern equatorial Pacific shadow zone. At depth, δ30Si values in the South Pacific remain indistinguishable from deep Southern Ocean values of +1.25‰, even within Si-rich and oxygen-poor deep waters returning from the North Pacific. This homogeneity implies that the dissolution of opal plays a negligible role in altering the δ30Si value of deep waters as they traverse the deep Pacific Ocean.

  9. Eastern Equatorial Pacific Sea Level Pressure (1949-present)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is one of the CPC?s Monthly Atmospheric and SST Indices. It contains standardized sea level pressure anomalies over the equatorial eastern Pacific region...

  10. Extreme winds in the Western North Pacific

    DEFF Research Database (Denmark)

    Ott, Søren

    2006-01-01

    A statistical model for extreme winds in the western North Pacific is developed, the region on the Planet where tropical cyclones are most common. The model is based on best track data derived mostly from satellite images of tropical cyclones. The methodsused to estimate surface wind speeds from...

  11. Hydrography of the eastern tropical Pacific: A review

    Science.gov (United States)

    Fiedler, Paul C.; Talley, Lynne D.

    2006-05-01

    Eastern tropical Pacific Ocean waters lie at the eastern end of a basin-wide equatorial current system, between two large subtropical gyres and at the terminus of two eastern boundary currents. Descriptions and interpretations of surface, pycnocline, intermediate and deep waters in the region are reviewed. Spatial and temporal patterns are discussed using (1) maps of surface temperature, salinity, and nutrients (phosphate, silicate, nitrate and nitrite), and thermocline and mixed layer parameters, and (2) meridional and zonal sections of temperature, salinity, potential density, oxygen, and nutrients. These patterns were derived from World Ocean Database observations by an ocean interpolation algorithm: loess-weighted observations were projected onto quadratic functions of spatial coordinates while simultaneously fitting annual and semiannual harmonics and the Southern Oscillation Index to account for interannual variability. Contrasts between the equatorial cold tongue and the eastern Pacific warm pool are evident in all the hydrographic parameters. Annual cycles and ENSO (El Niño-Southern Oscillation) variability are of similar amplitude in the eastern tropical Pacific, however, there are important regional differences in relative variability at these time scales. Unique characteristics of the eastern tropical Pacific are discussed: the strong and shallow pycnocline, the pronounced oxygen minimum layer, and the Costa Rica Dome. This paper is part of a comprehensive review of the oceanography of the eastern tropical Pacific.

  12. Expedition surveys of the sea water and atmospheric air radioactive contamination in the Russian Far Eastern coastal areas and in the North- Western Pacific in connection with accident at the 'Fukushima-1' NPP

    Energy Technology Data Exchange (ETDEWEB)

    Nikitin, Aleksandr; Shershakov, Viacheslav; Artemev, Georgii [Research and Production Association ' Typhoon' (RPA ' Typhoon' ), Obninsk, Kaluga Region (Russian Federation); Ramzaev, Valery [Ramzaev Saint-Petersburg Research Institute of Radiation Hygiene, Saint-Petersburg (Russian Federation); Osokin, Vladimir [V.G.Khlopin Radium institute, Saint-Petersburg (Russian Federation); Sevastianov, Aleksandr [Far Eastern Regional Hydrometeorological Research Institute, Vladivostok (Russian Federation)

    2014-07-01

    In accordance with decision of the Russian Federation Federal Service on Hydro-meteorology and Environmental Monitoring (Roshydromet) on assessment of the sea water and atmospheric air radioactive contamination in the Russian coastal areas of the Far East in connection with accident at the 'Fukushima-1' NPP in Japan, two radioecological expedition surveys were conducted onboard of research vessels of the Far Eastern Regional Hydro-meteorological Research Institute (FERHRI) of Roshydromet in the Sea of Japan and in the North-Western Pacific (in the area adjacent to Kurile Islands and in the Kuroshio current selected area (coordinates 36 deg. 00'- 39 deg. 33' n., 146 deg. 33'- 150 deg. 00' e.): first survey in April-May 2011, onboard R/V 'Pavel Gordienko', second survey in August-September 2012, onboard R/V 'Akademik Shokalsky'. Both surveys were conducted under the Russian Geographical Society patronage. The leading Russian institutions dealing with ensuring of population radiation safety and protection of environment from radioactive contamination were enlisted to investigations. The following main observations were performed during the surveys: constant measurement of gamma-radiation dose rate above the sea surface; twenty-four hour sampling of atmospheric aerosols, sea water sampling from the surface and deep water horizons with preliminary concentrating of radionuclides for onboard gamma-spectrometry and for subsequent transportation to the shore laboratories for further analysis. During the expeditions, a real-time data were received onboard of research vessels which characterize impact of input of radioactive products of the 'Fukushima-1' NPP accident on radioactive contamination of environment existed on that period (these are onboard estimates of {sup 137}Cs and {sup 134}Cs concentrations in the sea water samples and {sup 131}I, {sup 137}Cs, {sup 134}Cs content in atmospheric aerosol samples, data

  13. Authigenic Uranium in Eastern Equatorial Pacific Sediments

    Science.gov (United States)

    Marcantonio, F.; Lyle, M. W.; Loveley, M. R.; Ibrahim, R.

    2014-12-01

    Authigenic U concentrations have been used as an indicator of redox state in marine sediments. Soluble U(VI) in porewaters is reduced to insoluble U(IV) under suboxic conditions setting up a diffusion gradient through which U in bottom waters is supplied to reducing sediments. Researchers have used sedimentary redox enrichment of U as a tool to identify past redox changes, which may be caused by changes in organic carbon rain rates and/or bottom water oxygen levels. Differentiating between these two explanations is important, as the former is tied to the use of authigenic U as a paleoproductivity proxy. We examined sediments from 4 sediment cores retrieved from two different localities in the Panama Basin in the eastern equatorial Pacific. Two cores were retrieved from the northern Panama basin at the Cocos Ridge, (4JC at 5° 44.7'N 85° 45.5' W, 1730 m depth; 8JC at 6° 14.0'N 86° 2.6' W, 1993 m depth), and two were retrieved from the south at the Carnegie Ridge, (11JC at 0° 41.6'S 85° 20.0' W, 2452 m depth; 17JC at 0° 10.8'S 85° 52.0' W, 2846 m depth). Using 230Th systematics and seismic profiling at each of the sites, we've identified significant sediment winnowing (4JC and 11JC) and focusing (8JC and 17JC). At all sites, we believe that changes in age-model-derived sand (i.e., >63µm) mass accumulation rates (MAR) best represent changes in rain rates. Glacial rain rates are higher than those in the Holocene by a factor of 2-3 at both sites. Peak Mn levels (>1%), the brown-to-green color transition (which likely represents the oxic/post-oxic boundary), and peak U concentrations all appear in the same order with increasing depth down core. At the Carnegie sites, where MARs are greater than those at the Cocos sites, increases in authigenic U (up to 4 ppm) occur during the mid- to late Holocene at depths of 10-15 cm. At the Cocos sites, increases in authigenic U (up to 12 ppm) occur lower in the sediment column (25-30 cm) during the late glacial. The decrease

  14. Low oxygen eddies in the eastern tropical North Atlantic

    DEFF Research Database (Denmark)

    Grundle, D. S.; Löscher, C. R.; Krahmann, G.

    2017-01-01

    Nitrous oxide (N2O) is a climate relevant trace gas, and its production in the ocean generally increases under suboxic conditions. The Atlantic Ocean is well ventilated, and unlike the major oxygen minimum zones (OMZ) of the Pacific and Indian Oceans, dissolved oxygen and N2O concentrations...... in the Atlantic OMZ are relatively high and low, respectively. This study, however, demonstrates that recently discovered low oxygen eddies in the eastern tropical North Atlantic (ETNA) can produce N2O concentrations much higher (up to 115 nmol L-1) than those previously reported for the Atlantic Ocean, and which...... are within the range of the highest concentrations found in the open-ocean OMZs of the Pacific and Indian Oceans. N2O isotope and isotopomer signatures, as well as molecular genetic results, also point towards a major shift in the N2O cycling pathway in the core of the low oxygen eddy discussed here, and we...

  15. North Pacific atmospheric rivers and their influence on western North America at the Last Glacial Maximum

    Science.gov (United States)

    Lora, Juan M.; Mitchell, Jonathan L.; Risi, Camille; Tripati, Aradhna E.

    2017-01-01

    Southwestern North America was wetter than present during the Last Glacial Maximum. The causes of increased water availability have been recently debated, and quantitative precipitation reconstructions have been underutilized in model-data comparisons. We investigate the climatological response of North Pacific atmospheric rivers to the glacial climate using model simulations and paleoclimate reconstructions. Atmospheric moisture transport due to these features shifted toward the southeast relative to modern. Enhanced southwesterly moisture delivery between Hawaii and California increased precipitation in the southwest while decreasing it in the Pacific Northwest, in agreement with reconstructions. Coupled climate models that are best able to reproduce reconstructed precipitation changes simulate decreases in sea level pressure across the eastern North Pacific and show the strongest southeastward shifts of moisture transport relative to a modern climate. Precipitation increases of ˜1 mm d-1, due largely to atmospheric rivers, are of the right magnitude to account for reconstructed pluvial conditions in parts of southwestern North America during the Last Glacial Maximum.

  16. Phanerozoic tectonic evolution of the Circum-North Pacific

    Science.gov (United States)

    Nokleberg, Warren J.; Parfenov, Leonid M.; Monger, James W.H.; Norton, Ian O.; Khanchuk, Alexander I.; Stone, David B.; Scotese, Christopher R.; Scholl, David W.; Fujita, Kazuya

    2000-01-01

    The Phanerozoic tectonic evolution of the Circum-North Pacific is recorded mainly in the orogenic collages of the Circum-North Pacific mountain belts that separate the North Pacific from the eastern part of the North Asian Craton and the western part of the North American Craton. These collages consist of tectonostratigraphic terranes that are composed of fragments of igneous arcs, accretionary-wedge and subduction-zone complexes, passive continental margins, and cratons; they are overlapped by continental-margin-arc and sedimentary-basin assemblages. The geologic history of the terranes and overlap assemblages is highly complex because of postaccretionary dismemberment and translation during strike-slip faulting that occurred subparallel to continental margins.We analyze the complex tectonics of this region by the following steps. (1) We assign tectonic environments for the orogenic collages from regional compilation and synthesis of stratigraphic and faunal data. The types of tectonic environments include cratonal, passive continental margin, metamorphosed continental margin, continental-margin arc, island arc, oceanic crust, seamount, ophiolite, accretionary wedge, subduction zone, turbidite basin, and metamorphic. (2) We make correlations between terranes. (3) We group coeval terranes into a single tectonic origin, for example, a single island arc or subduction zone. (4) We group igneous-arc and subduction- zone terranes, which are interpreted as being tectonically linked, into coeval, curvilinear arc/subduction-zone complexes. (5) We interpret the original positions of terranes, using geologic, faunal, and paleomagnetic data. (6) We construct the paths of tectonic migration. Six processes overlapping in time were responsible for most of the complexities of the collage of terranes and overlap assemblages around the Circum-North Pacific, as follows. (1) During the Late Proterozoic, Late Devonian, and Early Carboniferous, major periods of rifting occurred along

  17. Problems and prospects in North Eastern Coalfields

    Energy Technology Data Exchange (ETDEWEB)

    Gulati, A.K.; Jha, M.N.

    1989-02-01

    North eastern region, very well known as land of seven sisters, comprises of the States of Assam, Meghalaya, Tripura, Manipur, Nagaland, Mizoram and Arunachal Pradesh. Some of the minerals like oil and coal are concealed in this region in dense forests and difficult terrain. North Eastern Coalfields being directly administered by Coal India Ltd. is responsible for exploitation of coal in this region. At present all the working mines are situated in the State of Assam only. One Simsong UG project will be started this year in the State of Meghalaya and coal deposits of Nagaland and Arunachal Pradesh are likely to be worked in Eighth Five Year Plan. In the remaining three States, i.e. Mizoram, Manipur and Tripura no occurrence of coal deposit has been found so far. 6 tabs.

  18. Identification of CO2 disposal locations in an ocean general circulation model of the North Pacific

    Institute of Scientific and Technical Information of China (English)

    XU Yongfu; AOKI Shigeaki; HARADA Koh

    2009-01-01

    A basin-wide ocean general circulation model of the North Pacific is used to identify which location is more effi-cient for ocean CO2 sequestration in the North Pacific. Four injection depths at each one of fifteen locations are chosen. In terms of effectiveness index (EI) and escape factor (EF), it is clear that the effectiveness increases with increasing latitude at the end of the 50 a injection period. Site-by-site differences in the EI can be over 9% for the 1 000 m injection depth in the western North Pacific at the end of 50 a of continuous injection. The difference is much larger for the 500 m injection. The difference decreases with increasing injection depth. However, the site-by-site difference is small for the injection in the eastern North Pacific. The sequestration is more efficient for the injection in the east than in the west. For the 500 m injection depth, the difference in ef-fectiveness between the west and the east is over 10% at the end of 50 a injection period. The largest concentra-tion of sequestered CO2 increases with increasing injection depth. For the injection in both the western and cen-tral North Pacific, the largest exchange flux always appears to be at about 42°N, 150°E, whereas for the injec-tion in the eastern area the large flux appears to be in the equatorial region (120°W).

  19. Climate Prediction Center (CPC) East Pacific/ North Pacific Teleconnection Pattern Index

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Monthly tabulated index of the East Pacific/ North Pacific teleconnection pattern. The data spans the period 1950 to present. The index is derived from a rotated...

  20. Silicon stable isotope distribution traces Southern Ocean export of Si to the eastern South Pacific thermocline

    Directory of Open Access Journals (Sweden)

    G. F. de Souza

    2012-06-01

    Full Text Available The cycling and transport of dissolved silicon (Si in the ocean may be traced by its stable isotope composition, δ30Si. We present a dataset of δ30Si values along 103° W in the eastern South Pacific Ocean, ranging from the Antarctic Zone of the Southern Ocean (62° S to the equatorial Pacific (12° S. At high southern latitudes, the uptake and associated isotope fractionation of Si by diatoms results in highly elevated δ30Si values (up to +3.2 ‰ in the summer mixed layer. The efficient export of diatom opal to depths inaccessible to annual winter convection is reflected by high δ30Si values (+2 ‰ preserved in high-latitude winter mixed layers. These elevated δ30Si values are introduced into the ocean interior by the subduction of Subantarctic Mode Water (SAMW and Antarctic Intermediate Water (AAIW, whose northward spreading results in a strong isopycnal control on lower-thermocline and intermediate δ30Si values in the well-ventilated eastern South Pacific. Values of δ30Si are strongly conserved along SAMW and AAIW density levels as far north as 26° S, documenting the importance of the export of preformed Si from the surface Southern Ocean to lower latitudes. In contrast, in the equatorial Pacific, depressed δ30Si values in the mesopelagic ocean are observed, most likely documenting the combined influence of a North Pacific Si source as well as the accumulation of remineralized Si within the eastern equatorial Pacific shadow zone. At depth, δ30Si values in the South Pacific remain indistinguishable from deep Southern Ocean values of +1.25 ‰, even within Si-rich and oxygen-poor deep waters returning from the North Pacific. This homogeneity implies that the dissolution of opal plays a negligible role in altering the δ30Si value of deep waters as they traverse the deep Pacific Ocean.

  1. Geographic variation in Pacific herring growth in response to regime shifts in the North Pacific Ocean

    Science.gov (United States)

    Ito, Shin-ichi; Rose, Kenneth A.; Megrey, Bernard A.; Schweigert, Jake; Hay, Douglas; Werner, Francisco E.; Aita, Maki Noguchi

    2015-11-01

    locations and increased growth at the Sakhalin, WBS and Togiak locations after 1977. The SO location belonged to the same cluster as the location in with the eastern North Pacific. The calibrated half-saturation coefficients affected the degree to which growth was sensitive to interannual variation in water temperature versus zooplankton. For example, the half-saturation values for the SO location resulted in very efficient feeding that shifted the sensitivity of herring growth from food to temperature. The model results demonstrate how geographic specificity of bioenergetics parameters, coupled with location-specific variation in temperature and food, can combine to determine local and regional responses of fish growth to climate forcing.

  2. Addressing wind integration issues in north eastern North America

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-03-27

    Wind energy has been growing rapidly in the north eastern region of North America in response to an increasing focus on security of supply issues and greater public concern over climate change. The purpose of this report was to address the issues associated with wind integration in the north east by evaluating issues that inhibit the transmission of wind; identifying actions that will improve the integration of wind; and profiling processes that could facilitate the uptake of wind. Specifically, the report sought to identify wind integration issues that may arise in the north east region in the next 5 to 10 year period. The report provided an overview of the north east and its wind resource, including an overview of the north east electricity market; wind energy overview; and intermittent wind farms. The global experience of wind integration to date was also presented. This included long-term wind vision; wind resource data set; multi-integration studies; upgrading and expanding transmissions systems; balancing area size; forecasting; geographical diversity; increasing system flexibility; and whole sale markets. A north east wind integration seminar was also highlighted. It was concluded that large scale wind could produce sufficient revenues to pay for the addition of substantial transmission with added benefits to the loads. 37 refs., 17 figs., 2 appendices.

  3. Decadal variability in the Eastern North Atlantic

    Science.gov (United States)

    Köllner, Manuela; Klein, Birgit; Kieke, Dagmar; Klein, Holger; Rhein, Monika; Roessler, Achim; Denker, Claudia

    2016-04-01

    The strong warming and salinification of the Eastern North Atlantic starting in the mid 1990s has been attributed to a westward contraction of the subpolar gyre and stronger inflow of waters from the subtropical gyre. Temporal changes in the shape and strength of the two gyres have been related to the major mode of atmospheric variability in the Atlantic sector, the NAO. Hydrographic conditions along the Northwest European shelf are thus the result of different processes such as variations in transports, varying relative contributions of water masses from the two gyres and property trends in the source water masses. We examine the decadal variability in the eastern North Atlantic based on Argo data from 2000-2015 and have constructed time series for four water masses (Subpolar Mode Water (SPMW), Intermediate Water (IW), upper Labrador Sea Water (uLSW) and deep Labrador Sea Water (dLSW)) at selected locations along the Northwest European shelf. Data from the Rockall Trough and the Iceland Basin are chosen to represent advective pathways in the subpolar gyre at two major branches of the North Atlantic Current towards the Nordic Seas and the Arctic Ocean. Temporal variability of subtropical waters transported northward along the eastern boundary is studied at Goban Spur around 48°N. The Argo data are extended in time with long-term hydrographic observations such as the Extended Ellet Line data and other climatological sources in the region. For the study of transport fluctuations time series from the RACE (Regional circulation and Global change) program (2012-2015) and predecessor programs have been used. These programs have monitored the subpolar gyre in the western basin and provide time series of transports and hydrographic anomalies from moored instruments at the western flank of the Mid Atlantic Ridge (MAR). First results show that the temperatures and salinities remained at high levels for the upper waters (SPMW and IW) until 2010 and have been decreasing since

  4. Temperature and zooplankton size structure: climate control and basin-scale comparison in the North Pacific.

    Science.gov (United States)

    Chiba, Sanae; Batten, Sonia D; Yoshiki, Tomoko; Sasaki, Yuka; Sasaoka, Kosei; Sugisaki, Hiroya; Ichikawa, Tadafumi

    2015-02-01

    The global distribution of zooplankton community structure is known to follow latitudinal temperature gradients: larger species in cooler, higher latitudinal regions. However, interspecific relationships between temperature and size in zooplankton communities have not been fully examined in terms of temporal variation. To re-examine the relationship on a temporal scale and the effects of climate control thereon, we investigated the variation in copepod size structure in the eastern and western subarctic North Pacific in 2000-2011. This report presents the first basin-scale comparison of zooplankton community changes in the North Pacific based on a fully standardized data set obtained from the Continuous Plankton Recorder (CPR) survey. We found an increase in copepod community size (CCS) after 2006-2007 in the both regions because of the increased dominance of large cold-water species. Sea surface temperature varied in an east-west dipole manner, showing the typical Pacific Decadal Oscillation pattern: cooling in the east and warming in the west after 2006-2007. The observed positive correlation between CCS and sea surface temperature in the western North Pacific was inconsistent with the conventional interspecific temperature-size relationship. We explained this discrepancy by the geographical shift of the upper boundary of the thermal niche, the 9°C isotherm, of large cold-water species. In the eastern North Pacific, the boundary stretched northeast, to cover a large part of the sampling area after 2006-2007. In contrast, in the western North Pacific, the isotherm location hardly changed and the sampling area remained within its thermal niche throughout the study period, despite the warming that occurred. Our study suggests that while a climate-induced basin-scale cool-warm cycle can alter copepod community size and might subsequently impact the functions of the marine ecosystem in the North Pacific, the interspecific temperature-size relationship is not

  5. Long-term variability of surface nutrient concentrations in the North Pacific

    Science.gov (United States)

    Yasunaka, S.; Ono, T.; Nojiri, Y.; Whitney, F. A.; Wada, C.; Murata, A.; Nakaoka, S.; Hosoda, S.

    2016-04-01

    We present the spatial distributions and temporal changes of the long-term variability of surface nutrient concentrations in the North Pacific by using nutrient samples collected by volunteer ships and research vessels from 1961 to 2012. Nutrient samples are optimally interpolated onto 1° × 1° monthly grid boxes. When the Pacific Decadal Oscillation is in its positive phase, nutrient concentrations in the western North Pacific are significantly higher than the climatological means, and those in the eastern North Pacific are significantly lower. When the North Pacific Gyre Oscillation is in its positive phase, nutrient concentrations in the subarctic are significantly higher than the climatological means. The trends of phosphate and silicate averaged over the North Pacific are -0.012 ± 0.005 µmol l-1 decade-1 and -0.38 ± 0.13 µmol l-1 decade-1, whereas the nitrate trend is not significant (0.01 ± 0.13 µmol l-1 decade-1).

  6. A dissolved cobalt plume in the oxygen minimum zone of the eastern tropical South Pacific

    Science.gov (United States)

    Hawco, Nicholas J.; Ohnemus, Daniel C.; Resing, Joseph A.; Twining, Benjamin S.; Saito, Mak A.

    2016-10-01

    Cobalt is a nutrient to phytoplankton, but knowledge about its biogeochemical cycling is limited, especially in the Pacific Ocean. Here, we report sections of dissolved cobalt and labile dissolved cobalt from the US GEOTRACES GP16 transect in the South Pacific. The cobalt distribution is closely tied to the extent and intensity of the oxygen minimum zone in the eastern South Pacific with highest concentrations measured at the oxycline near the Peru margin. Below 200 m, remineralization and circulation produce an inverse relationship between cobalt and dissolved oxygen that extends throughout the basin. Within the oxygen minimum zone, elevated concentrations of labile cobalt are generated by input from coastal sources and reduced scavenging at low O2. As these high cobalt waters are upwelled and advected offshore, phytoplankton export returns cobalt to low-oxygen water masses underneath. West of the Peru upwelling region, dissolved cobalt is less than 10 pM in the euphotic zone and strongly bound by organic ligands. Because the cobalt nutricline within the South Pacific gyre is deeper than in oligotrophic regions in the North and South Atlantic, cobalt involved in sustaining phytoplankton productivity in the gyre is heavily recycled and ultimately arrives from lateral transport of upwelled waters from the eastern margin. In contrast to large coastal inputs, atmospheric deposition and hydrothermal vents along the East Pacific Rise appear to be minor sources of cobalt. Overall, these results demonstrate that oxygen biogeochemistry exerts a strong influence on cobalt cycling.

  7. 77 FR 53179 - North Pacific Fishery Management Council; Public Meeting

    Science.gov (United States)

    2012-08-31

    ... total catch accounting, recruitment and retrospective analyses, a review of the economic stock... National Oceanic and Atmospheric Administration RIN 0648-XC195 North Pacific Fishery Management Council... Administration (NOAA), Commerce. ACTION: Notice of a public meeting. SUMMARY: The North Pacific Fishery...

  8. 78 FR 78824 - North Pacific Fishery Management Council; Public Meeting

    Science.gov (United States)

    2013-12-27

    ... National Oceanic and Atmospheric Administration RIN 0648-XD055 North Pacific Fishery Management Council... Administration (NOAA), Commerce. ACTION: The North Pacific Fishery Management Council (NPFMC) will hold a Crab Modeling Workshop. SUMMARY: The workshop will be held January 14-17 at the Hilton Hotel, 500 West Third...

  9. 75 FR 54092 - North Pacific Fishery Management Council; Public Meeting

    Science.gov (United States)

    2010-09-03

    ...-XY69 North Pacific Fishery Management Council; Public Meeting AGENCY: National Marine Fisheries Service... meeting. SUMMARY: The North Pacific Fishery Management Council's (Council) Scallop Plan Team will meet September 28th, 2010 at the Anchorage Hilton Hotel. DATES: The meeting will be held on September 28, 2010...

  10. Dynamic Mechanism of Interannual Sea Surface Height Variability in the North Pacific Subtropical Gyre

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yong-Chui; ZHANG Li-Feng; L(U) Qing-Ping

    2011-01-01

    In this study, the dynamic mechanisms of interannual sea surface height (SSH) variability are investigated based on the first-mode baroclinic Rossby wave model, with a focus on the effects of different levels of wind stress curl (WSC)、 Maximum covariance analysis (MCA) of WSC and SSH anomalies displays a mode with significant WSC anomalies located primarily in the mid-latitude eastern North Pacific and central tropical Pacific with corresponding SSH anomalies located to the west. This leading mode can be attributed to Ekman pumping induced by local wind stress and the westward-propagating Rossby wave driven by largescale wind stress. It is further found that in the middle latitudes, the SSH anomalies are largely determined by WSC variations associated with the North Pacific Gyre Oscillation (NPGO)、 rather than the Pacific Decadal Oscillation (PDO). The sensitivity of the predictive skill of the linear first-mode baroclinic model to different wind products is also examined.

  11. Towards understanding North Pacific climate variabilty with instrumental and ice core records

    Science.gov (United States)

    Kelsey, Eric P.

    Reconstructing climate variability prior to the instrumental era is critical to advance our understanding of the Earth's climate system. Although many paleoclimate records from the North Atlantic basin have been studied, relatively few paleoclimate records have been recovered in the North Pacific leaving a gap in our knowledge concerning North Pacific climate variability. The Eclipse and Mount Logan Prospector-Russell ice cores are favorably located in the St. Elias Mountains, Yukon, Canada to document North Pacific climate variability over the late Holocene. Detailed analysis reveals a consistent relationship of surface air temperature (SAT) anomalies associated with extreme Arctic Oscillation (AO) and Pacific-North America (PNA) index values, and a consistent relationship of North Pacific sea level pressure (SLP) anomalies associated with extreme Mt. Logan annual [Na+] and Eclipse cold season accumulation values. Spatial SAT anomaly patterns are most consistent for AO and PNA index values ≥1.5 and ≤-1.5 during the period 1872-2010. The highest and lowest ˜10% of Eclipse warm and cold season stable isotopes are associated with distinct atmospheric circulation patterns. The most-fractionated isotope values occur with a weaker Aleutian Low, and the least-fractionated isotope values occur with an amplification of the Aleutian Low and northwestern North American ridge. The assumption of stationarity between ice core records and sea-level pressure was tested for the Eclipse cold season accumulation and Mt. Logan annual sodium concentration records for 1872-2001. A stationary relationship was found for ≥95% of years when Mt. Logan sodium concentrations were ≤1.32 microg/L, with positive SLP anomalies in the eastern North Pacific. This high frequency supports the use of low sodium values at Mt. Logan for a reconstruction of SLP prior to 1872. Negative SLP anomalies in the North Pacific occurred for extreme high sodium concentration years and positive SLP

  12. Parabolic dunes in north-eastern Brazil

    CERN Document Server

    Duran, O; Bezerra, L J C; Herrmann, H J; Maia, L P

    2007-01-01

    In this work we present measurements of vegetation cover over parabolic dunes with different degree of activation along the north-eastern Brazilian coast. We are able to extend the local values of the vegetation cover density to the whole dune by correlating measurements with the gray-scale levels of a high resolution satellite image of the dune field. The empirical vegetation distribution is finally used to validate the results of a recent continuous model of dune motion coupling sand erosion and vegetation growth.

  13. Impacts of an Improved Low-Level Cloud Scheme on the Eastern Pacific ITCZ-Cold Tongue Complex

    Institute of Scientific and Technical Information of China (English)

    DM Fushan; YU Rucong; ZHANG Xuehong; YU Yongqiang; LI Jianglong

    2005-01-01

    A statistically-based low-level cloud parameterization scheme is introduced, modified, and applied in the Flexible coupled General Circulation Model (FGCM-0). It is found that the low-level cloud scheme makes improved simulations of low-level cloud fractions and net surface shortwave radiation fluxes in the subtropical eastern oceans off western coasts in the model. Accompanying the improvement in the net surface shortwave radiation fluxes, the simulated distribution of SSTs is more reasonably asymmetrical about the equator in the tropical eastern Pacific, which suppresses, to some extent, the development of the double ITCZ in the model. Warm SST biases in the ITCZ north of the equator are more realistically reduced, too. But the equatorial cold tongue is strengthened and extends further westward, which reduces the precipitation rate in the western equatorial Pacific but increases it in the ITCZ north of the equator in the far eastern Pacific. It is demonstrated that the low-level cloud-radiation feedback would enhance the cooperative feedback between the equatorial cold tongue and the ITCZ. Based on surface layer heat budget analyses, it is demonstrated that the reduction of SSTs is attributed to both the thermodynamic cooling process modified by the increase of cloud fractions and the oceanic dynamical cooling processes associated with the strengthened surface wind in the eastern equatorial Pacific, but it is mainly attributed to oceanic dynamical cooling processes associated with the strengthening of surface wind in the central and western equatorial Pacific.

  14. Past and Future Directions of North Pacific Tephrochronology

    Science.gov (United States)

    Sarna-Wojcicki, A. M.

    2004-12-01

    The north Pacific Ocean is rimmed by a complex of subduction zones that dip away from the ocean basin toward the fringing island arcs and continents. Inboard of these subduction zones is a belt of persistent volcanic activity--the Pacific "Ring of Fire"--formed by partial melting of subducted oceanic crust and overlying continental crust. Magma bodies of intermediate to silicic composition at many sites along this active volcanic belt have given rise to explosive volcanic eruptions and wide dispersal of tephra throughout the north Pacific Ocean and adjacent land areas. Moreover, along some parts of the north Pacific rim, as well as farther inboard of the subduction zones, are several persistent loci of crustal extension, translation, and hot spot activity that have also been sites of magma generation and large-volume explosive volcanism. Tephra erupted from these combined sources has been carried mostly in the direction of the prevailing winds, generally from west to east, though distributions have been complex, depending on heights of erupting columns and the prevailing weather and climate (including the seasons of eruption, positions of high- and low-pressure areas, and configurations of the jet stream). Tephra deposits formed as a consequence of this volcanic activity provide an important scientific resource for chronostratigraphy and correlation, and contribute significantly to solution of regional and topical studies in earth science. Tephra studies in Japan, the western conterminous United States, and southwestern Canada have advanced to the point that regional spatial-temporal late Noegene tephrochronological reference frameworks exist for these areas. In northwestern Canada, Alaska, Kamchatka, and eastern Siberia, the development of these stratigraphic frameworks lags, owing to lower population density, more difficult access, and shorter field seasons. Tephrochronologic studies of ocean sediment cores have been more sporadic than systematic, and lag behind

  15. Radiostrontium monitoring of bivalves from the Pacific coast of eastern Japan.

    Science.gov (United States)

    Karube, Zin'ichi; Inuzuka, Yoko; Tanaka, Atsushi; Kurishima, Katsuaki; Kihou, Nobuharu; Shibata, Yasuyuki

    2016-09-01

    In early April 2011, radiostrontium was accidentally released from the Fukushima Daiichi Nuclear Power Plant to the Pacific coast of eastern Japan. We developed a simple procedure to analyze radiostrontium levels in marine mussels (Septifer virgatus) and seawater using crown ether (Sr Resin; Eichrom). Then, we used our method to describe the spatial and temporal distribution of radiostrontium in mussels and seawater on the Pacific coast of eastern Japan from 2011 to 2013 and for 2015. Activity of (90)Sr in mussels and seawater decreased with distance from the Fukushima Daiichi Nuclear Power Plant and between 2011 and 2013 tended to be higher in areas south of the Fukushima Daiichi Nuclear Power Plant than to the north of it. Activity in mussels and seawater also tended to decrease from 2011 to 2013 and by 2015 had reached levels experienced prior to the Fukushima accident. Our results suggest that radiostrontium discharged from the Fukushima Daiichi Nuclear Power Plant was dispersed by coastal currents in a southerly direction along the Pacific coast of eastern Japan from 2011 to 2013, following which its activity decreased to background levels by 2015.

  16. Diversity of Pseudo-nitzschia from the western North Pacific

    DEFF Research Database (Denmark)

    Stonik, Inna V; Orlova, Tatiana Yu; Lundholm, Nina

    2011-01-01

    Asurvey focusing on species belonging to the diatom genus Pseudo-nitzschia was conducted in the western North Pacific (the northwestern Sea of Japan and the Sea of Okhotsk). Light and electron microscopic examination of 314 phytoplankton field samples collected from 1995 to 2006 revealed...... are provided for all 11 Pseudo-nitzschia taxa. The study presents a taxonomical baseline investigation of Pseudo-nitzschia from the western North Pacific and provides distributional data from an area otherwise not thoroughly examined earlier. Morphological deviation from the current description of P. cf...... to the northern hemisphere where it occurs in the North Atlantic Ocean exclusively. The current study, however, documents that P. seriata is found in the North Pacific and hence is widespread in the northern hemisphere. One species, P. cf. caciantha, is a new record for the western North Pacific, whereas two...

  17. Two-types of Early Cretaceous adakitic porphyries from the Luxi terrane, eastern North China Block: Melting of subducted Paleo-Pacific slab and delaminated newly underplated lower crust

    Science.gov (United States)

    Wang, Hao; Xu, Zhaowen; Lu, Xiancai; Fu, Bin; Lu, Jianjun; Yang, Xiaonan; Zhao, Zengxia

    2016-01-01

    The origin and tectonic setting of Early Cretaceous adakitic rocks from the Luxi terrane in the eastern North China Block (NCB) remain debated. To resolve this issue, we determined whole-rock geochemistry, zircon U-Pb ages, and in situ Hf-O isotopes of the Mengyin and Liujing adakitic porphyries from the Luxi terrane. Zircon U-Pb dating results reveal that both the Mengyin and Liujing plutons were emplaced during the Early Cretaceous, with weighted mean 206Pb/238U ages of 130 ± 1 Ma (2σ) and 131 ± 2 Ma (2σ), respectively. In addition, abundant Neoarchean-Paleoproterozoic inherited zircon cores are identified in the Mengyin adakitic porphyry with 207Pb/206Pb ages ranging from 2.53 to 2.42 Ga. Rocks of both plutons are silicic (SiO2 = 65.4-70.2 wt.%), metaluminous, and alkaline in composition, comprising mainly quartz syenite porphyries. Samples from both plutons are enriched in large ion lithophile elements (LILEs) (e.g., Rb, Sr, and Ba), and light rare earth elements (LREEs), depleted in high field strength elements (HFSEs) (e.g., Nb, Ta, and Ti), and heavy rare earth elements (HREEs), and have either positive or no Eu anomalies. In addition, both adakitic porphyries have high Mg# values (51-64), high Sr and La contents, low Y and Yb contents, and high Sr/Y (Mengyin = 149-264; Liujing = 58-110) and (La/Yb)N (Mengyin = 32.4-45.3; Liujing = 43.8-53.1) ratios, similar to adakitic rocks worldwide. The Mengyin adakitic porphyry has higher whole-rock εNd(t) values (-5.8 to - 4.1), more radiogenic Pb [(206Pb/204Pb)i = 18.35-18.39, (207Pb/204Pb)i = 15.55-15.56, (208Pb/204Pb)i = 38.20-38.23], higher zircon rim εHf(t) values (+ 3.3 to + 8.8) and δ18O values (+ 6.5‰ to + 7.9‰), and lower (87Sr/86Sr)i ratios (0.7049-0.7050) than the Liujing adakitic porphyry [εNd(t) = - 12.4 to - 12.2, (206Pb/204Pb)i = 17.63-17.72, (207Pb/204Pb)i = 15.56-15.58, (208Pb/204Pb)i = 37.76-37.94, εHf(t) = - 14.8 to - 11.2, δ18O = + 5.9‰ to + 7.1‰, (87Sr/86Sr)i = 0.7090-0.7091]. The

  18. Marine proxy evidence linking decadal North Pacific and Atlantic climate

    Energy Technology Data Exchange (ETDEWEB)

    Hetzinger, S. [University of Toronto Mississauga, CPS-Department, Mississauga, ON (Canada); Leibniz Institute of Marine Sciences, IFM-GEOMAR, Kiel (Germany); Halfar, J. [University of Toronto Mississauga, CPS-Department, Mississauga, ON (Canada); Mecking, J.V.; Keenlyside, N.S. [Leibniz Institute of Marine Sciences, IFM-GEOMAR, Kiel (Germany); University of Bergen, Geophysical Institute and Bjerknes Centre for Climate Research, Bergen (Norway); Kronz, A. [University of Goettingen, Geowissenschaftliches Zentrum, Goettingen (Germany); Steneck, R.S. [University of Maine, Darling Marine Center, Walpole, ME (United States); Adey, W.H. [Smithsonian Institution, Department of Botany, Washington, DC (United States); Lebednik, P.A. [ARCADIS U.S. Inc., Walnut Creek, CA (United States)

    2012-09-15

    Decadal- to multidecadal variability in the extra-tropical North Pacific is evident in 20th century instrumental records and has significant impacts on Northern Hemisphere climate and marine ecosystems. Several studies have discussed a potential linkage between North Pacific and Atlantic climate on various time scales. On decadal time scales no relationship could be confirmed, potentially due to sparse instrumental observations before 1950. Proxy data are limited and no multi-centennial high-resolution marine geochemical proxy records are available from the subarctic North Pacific. Here we present an annually-resolved record (1818-1967) of Mg/Ca variations from a North Pacific/Bering Sea coralline alga that extends our knowledge in this region beyond available data. It shows for the first time a statistically significant link between decadal fluctuations in sea-level pressure in the North Pacific and North Atlantic. The record is a lagged proxy for decadal-scale variations of the Aleutian Low. It is significantly related to regional sea surface temperature and the North Atlantic Oscillation (NAO) index in late boreal winter on these time scales. Our data show that on decadal time scales a weaker Aleutian Low precedes a negative NAO by several years. This atmospheric link can explain the coherence of decadal North Pacific and Atlantic Multidecadal Variability, as suggested by earlier studies using climate models and limited instrumental data. (orig.)

  19. Analysis of longitudinal variations in North Pacific alkalinity to improve predictive algorithms

    Science.gov (United States)

    Fry, Claudia H.; Tyrrell, Toby; Achterberg, Eric P.

    2016-10-01

    The causes of natural variation in alkalinity in the North Pacific surface ocean need to be investigated to understand the carbon cycle and to improve predictive algorithms. We used GLODAPv2 to test hypotheses on the causes of three longitudinal phenomena in Alk*, a tracer of calcium carbonate cycling. These phenomena are (a) an increase from east to west between 45°N and 55°N, (b) an increase from west to east between 25°N and 40°N, and (c) a minor increase from west to east in the equatorial upwelling region. Between 45°N and 55°N, Alk* is higher on the western than on the eastern side, and this is associated with denser isopycnals with higher Alk* lying at shallower depths. Between 25°N and 40°N, upwelling along the North American continental shelf causes higher Alk* in the east. Along the equator, a strong east-west trend was not observed, even though the upwelling on the eastern side of the basin is more intense, because the water brought to the surface is not high in Alk*. We created two algorithms to predict alkalinity, one for the entire Pacific Ocean north of 30°S and one for the eastern margin. The Pacific Ocean algorithm is more accurate than the commonly used algorithm published by Lee et al. (2006), of similar accuracy to the best previously published algorithm by Sasse et al. (2013), and is less biased with longitude than other algorithms in the subpolar North Pacific. Our eastern margin algorithm is more accurate than previously published algorithms.

  20. Eastern Pacific cooling and Atlantic overturning circulation during the last deglaciation.

    Science.gov (United States)

    Kienast, Markus; Kienast, Stephanie S; Calvert, Stephen E; Eglinton, Timothy I; Mollenhauer, Gesine; François, Roger; Mix, Alan C

    2006-10-19

    Surface ocean conditions in the equatorial Pacific Ocean could hold the clue to whether millennial-scale global climate change during glacial times was initiated through tropical ocean-atmosphere feedbacks or by changes in the Atlantic thermohaline circulation. North Atlantic cold periods during Heinrich events and millennial-scale cold events (stadials) have been linked with climatic changes in the tropical Atlantic Ocean and South America, as well as the Indian and East Asian monsoon systems, but not with tropical Pacific sea surface temperatures. Here we present a high-resolution record of sea surface temperatures in the eastern tropical Pacific derived from alkenone unsaturation measurements. Our data show a temperature drop of approximately 1 degrees C, synchronous (within dating uncertainties) with the shutdown of the Atlantic meridional overturning circulation during Heinrich event 1, and a smaller temperature drop of approximately 0.5 degrees C synchronous with the smaller reduction in the overturning circulation during the Younger Dryas event. Both cold events coincide with maxima in surface ocean productivity as inferred from 230Th-normalized carbon burial fluxes, suggesting increased upwelling at the time. From the concurrence of equatorial Pacific cooling with the two North Atlantic cold periods during deglaciation, we conclude that these millennial-scale climate changes were probably driven by a reorganization of the oceans' thermohaline circulation, although possibly amplified by tropical ocean-atmosphere interaction as suggested before.

  1. Climate Prediction Center (CPC) Daily Pacific North American Index

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Pacific-North American pattern (PNA) is one of the leading teleconnection patterns in the Northern Hemisphere circulation. It is calculated as a Rotated...

  2. Possible Ballast Water Transfer of Lionfish to the Eastern Pacific Ocean.

    Science.gov (United States)

    MacIsaac, Hugh J; De Roy, Emma M; Leung, Brian; Grgicak-Mannion, Alice; Ruiz, Gregory M

    2016-01-01

    The Indo-Pacific Red Lionfish was first reported off the Florida coast in 1985, following which it has spread across much of the SE USA, Gulf of Mexico, and Caribbean Sea. Lionfish negatively impact fish and invertebrate assemblages and abundances, thus further spread is cause for concern. To date, the fish has not been reported on the Pacific coast of North or Central America. Here we examine the possibility of ballast water transfer of lionfish from colonized areas in the Atlantic Ocean to USA ports on the Pacific coast. Over an eight-year period, we documented 27 commercial vessel-trips in which ballast water was loaded in colonized sites and later discharged untreated into Pacific coast ports in the USA. California had the highest number of discharges including San Francisco Bay and Los Angeles-Long Beach. A species distribution model suggests that the probability of lionfish establishment is low for the western USA, Colombia and Panama, low to medium for Costa Rica, Nicaragua, El Salvador and Guatemala, medium to high for mainland Ecuador, and very high for western Mexico, Peru and the Galapagos Islands. Given the species' intolerance of freshwater conditions, we propose that ballast water exchange be conducted in Gatún Lake, Panama for western-bound vessels carrying 'risky' ballast water to prevent invasion of the eastern Pacific Ocean.

  3. Contributions of Asian pollution and SST forcings on precipitation change in the North Pacific

    Science.gov (United States)

    Yeh, Sang-Wook; So, Jihyeon; Lee, Jong-Won; Kim, Minjoong J.; Jeong, Jaein I.; Park, Rokjin J.

    2017-08-01

    East Asia has a significant concentration of pollutant aerosols, mostly due to rapid industrialization. Previous research indicates that the aerosol effect from Asian pollution outflow could account for the trend of increasing deep convective clouds, as well as an intensification of the storm track, over the North Pacific Ocean in winter since the mid-1990s. However, it is not clear whether such change is solely due to Asian pollutant forcings or not. To understand the relative roles of Asian pollutant aerosols and sea surface temperature (SST) forcings on the precipitation change in the North Pacific, we examine the interannual variation of particulate matter 2.5 (PM2.5) simulated in the global chemical transport model (GEOS-Chem) and the idealized experiments using the Community Atmosphere Model version 5 (CAM5) for 1986-2010. The composite analysis indicates that the changes in precipitation amount and storm track intensity in the southwestern North Pacific might be associated with the increase in PM2.5 concentration in East China. However, El Niño-like warming during the years of high PM2.5 concentration may also influence the precipitation amount, as well as the storm track intensity in the central and eastern North Pacific. Model experiments also indicate that the El Niño-like warming and the Asian pollutant aerosols have different effects on precipitation amounts in the North Pacific. Therefore, the precipitation changes, as well as the intensification of the storm track, in the North Pacific might be attributed to both Asian pollutant aerosols and SST forcing in the tropics.

  4. Statistical Characteristics of Mesoscale Eddies in the North Pacific Derived from Satellite Altimetry

    Directory of Open Access Journals (Sweden)

    Yu-Hsin Cheng

    2014-06-01

    Full Text Available The sea level anomaly data derived from satellite altimetry are analyzed to investigate statistical characteristics of mesoscale eddies in the North Pacific. Eddies are detected by a free-threshold eddy identification algorithm. The results show that the distributions of size, amplitude, propagation speed, and eddy kinetic energy of eddy follow the Rayleigh distribution. The most active regions of eddies are the Kuroshio Extension region, the Subtropical Counter Current zone, and the Northeastern Tropical Pacific region. By contrast, eddies are seldom observed around the center of the eastern part of the North Pacific Subarctic Gyre. The propagation speed and kinetic energy of cyclonic and anticyclonic eddies are almost the same, but anticyclonic eddies possess greater lifespans, sizes, and amplitudes than those of cyclonic eddies. Most eddies in the North Pacific propagate westward except in the Oyashio region. Around the northeastern tropical Pacific and the California currents, cyclonic and anticyclonic eddies propagate westward with slightly equatorward (197° average azimuth relative to east and poleward (165° deflection, respectively. This implies that the background current may play an important role in formation of the eddy pathway patterns.

  5. North Pacific Decadal Variability: Insights from a Biennial ENSO Environment

    Science.gov (United States)

    Achuthavarier, Deepthi; Schubert, Siegfried D.; Vikhliaev, Yury V.

    2016-01-01

    This study examines the mechanisms of the Pacific decadal oscillation (PDO) in the NASA GEOS-5 general circulation model (GCM). Similar to several other state-of-the-art GCMs, the El Niño-Southern Oscillation (ENSO) simulated by the GEOS-5 has a strong biennial periodicity. Since this is a model bias that precludes a strong role of ENSO, it provides a unique environment to assess the other leading mechanisms of North Pacific decadal variability. Despite the biennial ENSO periodicity, the model simulates a realistic PDO pattern in the North Pacific that is resolved as the first empirical orthogonal function (EOF) of winter mean sea surface temperature (SST). The spectrum of the PDO indicates no preferred periodicity. The SST anomalies associated with the PDO, particularly its basin wide structure, are primarily forced by the Aleutian low through Ekman transport. The slow geostrophic transport in association with the meridional adjustment of the subtropical gyre is limited to a narrow region in the Kuroshio-Oyashio extension, north of 40degN. The atmosphere's response to the PDO, while weak, projects onto the North Pacific Oscillation (NPO), a meridional dipole in sea level pressure. Both the lack of preferred periodicity and the weak atmospheric response indicate an air-sea coupled oscillation is an unlikely mechanism in this model. In agreement with recent studies, the NPO is correlated with the North Pacific Gyre Oscillation, which is another leading EOF of North Pacific SST variability. The results emphasize the role of atmospheric variability in the North Pacific SST modes, thereby bringing into question the potential for their predictability.

  6. Population structure and phylogeography reveal pathways of colonization by a migratory marine reptile (Chelonia mydas) in the central and eastern Pacific.

    Science.gov (United States)

    Dutton, Peter H; Jensen, Michael P; Frey, Amy; LaCasella, Erin; Balazs, George H; Zárate, Patricia; Chassin-Noria, Omar; Sarti-Martinez, Adriana Laura; Velez, Elizabeth

    2014-11-01

    Climate, behavior, ecology, and oceanography shape patterns of biodiversity in marine faunas in the absence of obvious geographic barriers. Marine turtles are an example of highly migratory creatures with deep evolutionary lineages and complex life histories that span both terrestrial and marine environments. Previous studies have focused on the deep isolation of evolutionary lineages (>3 mya) through vicariance; however, little attention has been given to the pathways of colonization of the eastern Pacific and the processes that have shaped diversity within the most recent evolutionary time. We sequenced 770 bp of the mtDNA control region to examine the stock structure and phylogeography of 545 green turtles from eight different rookeries in the central and eastern Pacific. We found significant differentiation between the geographically separated nesting populations and identified five distinct stocks (F ST = 0.08-0.44, P Chelonia mydas form a monophyletic group containing 3 subclades, with Hawaii more closely related to the eastern Pacific than western Pacific populations. The split between sampled central/eastern and western Pacific haplotypes was estimated at around 0.34 mya, suggesting that the Pacific region west of Hawaii has been a more formidable barrier to gene flow in C. mydas than the East Pacific Barrier. Our results suggest that the eastern Pacific was colonized from the western Pacific via the Central North Pacific and that the Revillagigedos Islands provided a stepping-stone for radiation of green turtles from the Hawaiian Archipelago to the eastern Pacific. Our results fit with a broader paradigm that has been described for marine biodiversity, where oceanic islands, such as Hawaii and Revillagigedo, rather than being peripheral evolutionary "graveyards", serve as sources and recipients of diversity and provide a mechanism for further radiation.

  7. Phospholipid synthesis rates in the eastern subtropical South Pacific Ocean

    Directory of Open Access Journals (Sweden)

    B. A. S. Van Mooy

    2008-02-01

    Full Text Available Membrane lipid molecules are a major component of planktonic organisms and this is particularly true of the microbial picoplankton that dominate the open ocean; with their high surface-area to volume ratios, the synthesis of membrane lipids places a major demand on their overall cell metabolism. Specifically, the synthesis of cell membrane phospholipids creates a demand for the nutrient phosphorus, and we sought to refine our understanding of the role of phospholipids in the upper ocean phosphorus cycle. We measured the rates of phospholipid synthesis in a transect of the eastern subtropical South Pacific from Easter Island to Concepcion, Chile as part of the BIOSOPE program. Our approach combined standard phosphorus radiotracer incubations and lipid extraction methods. We found that phospholipid synthesis rates varied from less than 1 to greater than 200 pmol P L−1 h−1, and that phospholipid synthesis contributed between less than 5% to greater than 22% of the total PO43− incorporation rate. Changes in the percentage that phospholipid synthesis contributed to total PO43− uptake were strongly correlated with the ratio of primary production to bacterial production, which supported our hypothesis that heterotrophic bacteria were the primary agents of phospholipid synthesis. The spatial variation in phospholipid synthesis rates underscored the importance of heterotrophic bacteria in the phosphorus cycle of the eastern subtropical South Pacific, particularly the hyperoligotrophic South Pacific subtropical gyre.

  8. Concentration in the North Eastern Nigeria's Yam Market: A Gini ...

    African Journals Online (AJOL)

    Concentration in the North Eastern Nigeria's Yam Market: A Gini Coefficient Analysis. ... yam differentiation were yam varieties and size or length and market information were ... Key word: Lorenz Curve, Gini Coefficient Analysis, Yam, Nigeria.

  9. Extreme winds in the Western North Pacific

    Energy Technology Data Exchange (ETDEWEB)

    Ott, S.

    2006-11-15

    A statistical model for extreme winds in the western North Pacific is developed, the region on the Planet where tropical cyclones are most common. The model is based on best track data derived mostly from satellite images of tropical cyclones. The methods used to estimate surface wind speeds from satellite images is discussed with emphasis on the empirical basis, which, unfortunately, is not very strong. This is stressed by the fact that Japanese and US agencies arrive at markedly different estimates. On the other hand, best track data records cover a long period of time and if not perfect they are at least coherent over time in their imperfections. Applying the the Holland model to the best track data, wind profiles can be assigned along the tracks. From this annual wind speed maxima at any particular point in the region can be derived. The annual maxima, in turn, are fitted to a Gumbel distribution using a generalization Abild's method that allows for data wind collected from multiple positions. The choice of this method is justified by a Monte Carlo simulation comparing it to two other methods. The principle output is a map showing fifty year winds in the region. The method is tested against observed winds from Philippine synoptic stations and fair agreement is found for observed and predicted 48 year maxima. However, the almost biasfree performance of the model could be fortuitous, since precise definitions of 'windspeed' in terms averaging time, height above ground and assumed surface roughness are not available, neither for best tracks nor for the synoptic data. The work has been carried out under Danish Research Agency grant 2104-04-0005 'Offshore wind power' and it also covers the findings and analysis carried out in connection with task 1.6 of the project 'Feasibility Assessment and Capacity Building for Wind Energy Development in Cambodia, The Philippines and Vietnam' during 2005-06 under contract 125-2004 with EU

  10. Interaction between the Pacific and Atlantic storm tracks and its implication on the North Atlantic Oscillation.

    Science.gov (United States)

    Drouard, M.; Rivière, G.; Arbogast, P.

    2012-04-01

    In this study, the connection between the Pacific and Atlantic storm tracks is investigated to better understand the influence of the Pacific flow on the North Atlantic Oscillation (NAO). The type of wave breaking in the North Atlantic area and the phase of the NAO have been shown to depend on the properties of the Pacific atmospheric flow (Franzke et al. 2004; Rivière and Orlanski 2007), but the key ingredients in the Pacific flow that influence the NAO are not well identified. The purpose of this study is to analyse the influence of the Pacific flow on the NAO by performing numerical experiments with the Marshall and Molteni (1993) three-level quasi-geostrophic model and by comparing our results with ECMWF data reanalysis. The NAO, defined by the first EOF of the geopotential height in the North Atlantic area, is well reproduced by long term simulations of the model forced by ERA40 data. Similar properties appear in the observed NAO and simulated NAO, in particular, the nature of the waves breaking (more anticyclonic during positive phase events and more cyclonic during negative phase events), their spatial scale (large-scale waves dominate during positive phase events and small-scale waves dominate during negative phase events) and the presence of a large-scale ridge in the eastern Pacific that reaches its maximum four days before the maximum of the positive phase events. In order to investigate the influence of this ridge onto the NAO, diagnostic tools (such as the refractive index) are first used. Then, different strategies of sensitivity numerical experiments (such as initial-value problems) are considered to confirm the role played by the Pacific ridge.

  11. Constraining Cretaceous subduction polarity in eastern Pacific from seismic tomography and geodynamic modeling

    Science.gov (United States)

    Liu, Lijun

    2014-11-01

    Interpretation of recent mantle seismic images below the America ignited a debate on the Cretaceous subduction polarity in the eastern Pacific Ocean. The traditional view is that the massive vertical slab wall under eastern North America resulted from an eastward Farallon subduction. An alternative interpretation attributes this prominent seismic structure to a westward subduction of the North American Plate against a stationary intraoceanic trench. Here I design quantitative subduction models to test these two scenarios, using their implied plate kinematics as velocity boundary conditions. Modeling results suggest that the westward subduction scenario could not produce enough slab volume as seismic images reveal, as is due to the overall slow subduction rate (~2.5 cm/yr). The results favor the continuous eastward Farallon subduction scenario, which, with an average convergence rate of >10 cm/yr prior to the Eocene, can properly generate both the volume and the geometry of the imaged lower mantle slab pile. The eastward subduction model is also consistent with most Cretaceous geological records along the west coast of North America.

  12. Contrasting Effects of Central Pacific and Eastern Pacific El Nino on Stratospheric Water Vapor

    Science.gov (United States)

    Garfinkel, Chaim I.; Hurwitz, Margaret M.; Oman, Luke D.; Waugh, Darryn W.

    2013-01-01

    Targeted experiments with a comprehensive chemistry-climate model are used to demonstrate that seasonality and the location of the peak warming of sea surface temperatures dictate the response of stratospheric water vapor to El Nino. In spring, El Nino events in which sea surface temperature anomalies peak in the eastern Pacific lead to a warming at the tropopause above the warm pool region, and subsequently to more stratospheric water vapor (consistent with previous work). However, in fall and in early winter, and also during El Nino events in which the sea surface temperature anomaly is found mainly in the central Pacific, the response is qualitatively different: temperature changes in the warm pool region are nonuniform and less water vapor enters the stratosphere. The difference in water vapor in the lower stratosphere between the two variants of El Nino approaches 0.3 ppmv, while the difference between the winter and spring responses exceeds 0.5 ppmv.

  13. Tropical Pacific impacts on cooling North American winters

    Science.gov (United States)

    Sigmond, Michael; Fyfe, John C.

    2016-10-01

    The North American continent generally experienced a cooling trend in winter over the early 2000s. This cooling trend represented a significant deviation from expected anthropogenic warming and so requires explanation. Previous studies indicate that climate variations in the tropical Pacific contributed to many mid-latitude climate variations over the early twenty-first century. Here we show using large ensembles of fully coupled, partially coupled and uncoupled model simulations that in northwest North America the winter cooling was primarily a remote response to climate fluctuations in the tropical Pacific. By contrast, in central North America the winter cooling appears to have resulted from a relatively rare fluctuation in mid-latitude circulation that was unrelated to the tropical Pacific. Our results highlight how decadal climate signals--both remote and local in origin--can together offset anthropogenic warming to produce continental-scale cooling.

  14. A Study of Transport and Impact Strength of Fukushima Nuclear Pollutants in the North Pacific Surface

    Institute of Scientific and Technical Information of China (English)

    FU Hongli; LI Wei; ZHANG Xuefeng; HAN Guijun; WANG Xidong; WU Xinrong; ZHANG Lianxin

    2014-01-01

    Based on the statistics of surface drifter data of 1979-2011 and the simulation of nuclear pollutant particulate move-ments simulated using high quality ocean reanalysis surface current dataset, the transport pathways and impact strength of Fuku-shima nuclear pollutants in the North Pacific have been estimated. The particulates are used to increase the sampling size and en-hance the representativeness of statistical results. The trajectories of the drifters and particulates are first examined to identify typical drifting pathways. The results show that there are three types of transport paths for nuclear pollutants at the surface: 1) most pollutant particles move eastward and are carried by the Kuroshio and Kuroshio-extension currents and reach the east side of the North Pacific after about 3.2-3.9 years;2) some particles travel with the subtropical circulation branch and reach the east coast of China after about 1.6 years according to one drifter trajectory and about 3.6 years according to particulate trajectories;3) a little of them travel with local, small scale circulations and reach the east coast of China after about 1.3-1.8 years. Based on the par-ticulates, the impact strength of nuclear pollutants at these time scales can be estimated according to the temporal variations of relative concentration combined with the radioactive decay rate. For example, Cesium-137, carried by the strong North Pacific current, mainly accumulates in the eastern North Pacific and its impact strength is 4%of the initial level at the originating Fuku-shima area after 4 years. Due to local eddies, Cesium-137 in the western North Pacific is 1%of the initial pollutant level after 1.5 years and continuously increases to 3%after 4 years. The vertical movement of radioactive pollutants is not taken into account in the present study, and the estimation accuracy would be improved by considering three-dimensional flows.

  15. Conservation of native Pacific trout diversity in western North America

    Science.gov (United States)

    Penaluna, Brooke E.; Abadía-Cardoso, Alicia; Dunham, Jason; García de León, Francisco J; Gresswell, Robert E.; Luna, Arturo Ruiz; Taylor, Eric B.; Shepard, Bradley B.; Al-Chokhachy, Robert K.; Muhlfeld, Clint C.; Bestgen, Kevin R.; Rogers, Kevin H.; Escalante, Marco A; Keeley, Ernest R; Temple, Gabriel; Williams, Jack E.; Matthews, Kathleen; Pierce, Ron; Mayden, Richard L.; Kovach, Ryan; Garza, John Carlos; Fausch, Kurt D.

    2016-01-01

    Pacific trout Oncorhynchus spp. in western North America are strongly valued in ecological, socioeconomic, and cultural views, and have been the subject of substantial research and conservation efforts. Despite this, the understanding of their evolutionary histories, overall diversity, and challenges to their conservation is incomplete. We review the state of knowledge on these important issues, focusing on Pacific trout in the genus Oncorhynchus. Although most research on salmonid fishes emphasizes Pacific salmon, we focus on Pacific trout because they share a common evolutionary history, and many taxa in western North America have not been formally described, particularly in the southern extent of their ranges. Research in recent decades has led to the revision of many hypotheses concerning the origin and diversification of Pacific trout throughout their range. Although there has been significant success at addressing past threats to Pacific trout, contemporary and future threats represented by nonnative species, land and water use activities, and climate change pose challenges and uncertainties. Ultimately, conservation of Pacific trout depends on how well these issues are understood and addressed, and on solutions that allow these species to coexist with a growing scope of human influences.

  16. A Review of the Systematics of Angel Sharks Emphasizing the Species of the Eastern Pacific Region with a Modified Set of Morphometrics for Order Squatiniformes

    OpenAIRE

    Alioto, Dominic

    2012-01-01

    Members of the monofamilial chondrichthyan order Squatiniformes, commonly known as angel sharks, sand devils, ange de mer, and angelotes, are primarily benthic dwelling sharks found mainly in temperate and sub-tropical parts of the Atlantic and Pacific Oceans. Squatiniformes are very easily recognized from other shark-like fishes, but the individual species within the order are much more difficult to distinguish from each other. In the eastern North Pacific (ENP) region, three species descrip...

  17. Eastern North America as an independent center of plant domestication.

    Science.gov (United States)

    Smith, Bruce D

    2006-08-15

    The status of eastern North America as an independent center of plant domestication has recently been called into question by a number of genetic and archaeological studies, which suggest that the region may not have witnessed the independent domestication of local crop plants, but rather may have been on the receiving end of domesticated crop plants introduced from Mexico. Here, I provide a synthesis of the currently available archaeological and genetic evidence from both eastern North America and Mexico regarding the spatial and temporal context of initial domestication of the four plant species identified as potential eastern North American domesticates: marshelder (Iva annua), chenopod (Chenopodium berlandieri), squash (Cucurbita pepo), and sunflower (Helianthus annuus). Genetic and archaeological evidence provides strong support for the independent domestication of all four of these plant species in the eastern United States and reconfirms the region as one of the world's independent centers of domestication.

  18. Natal foraging philopatry in eastern Pacific hawksbill turtles.

    Science.gov (United States)

    Gaos, Alexander R; Lewison, Rebecca L; Jensen, Michael P; Liles, Michael J; Henriquez, Ana; Chavarria, Sofia; Pacheco, Carlos Mario; Valle, Melissa; Melero, David; Gadea, Velkiss; Altamirano, Eduardo; Torres, Perla; Vallejo, Felipe; Miranda, Cristina; LeMarie, Carolina; Lucero, Jesus; Oceguera, Karen; Chácon, Didiher; Fonseca, Luis; Abrego, Marino; Seminoff, Jeffrey A; Flores, Eric E; Llamas, Israel; Donadi, Rodrigo; Peña, Bernardo; Muñoz, Juan Pablo; Ruales, Daniela Alarcòn; Chaves, Jaime A; Otterstrom, Sarah; Zavala, Alan; Hart, Catherine E; Brittain, Rachel; Alfaro-Shigueto, Joanna; Mangel, Jeffrey; Yañez, Ingrid L; Dutton, Peter H

    2017-08-01

    The complex processes involved with animal migration have long been a subject of biological interest, and broad-scale movement patterns of many marine turtle populations still remain unresolved. While it is widely accepted that once marine turtles reach sexual maturity they home to natal areas for nesting or reproduction, the role of philopatry to natal areas during other life stages has received less scrutiny, despite widespread evidence across the taxa. Here we report on genetic research that indicates that juvenile hawksbill turtles (Eretmochelys imbricata) in the eastern Pacific Ocean use foraging grounds in the region of their natal beaches, a pattern we term natal foraging philopatry. Our findings confirm that traditional views of natal homing solely for reproduction are incomplete and that many marine turtle species exhibit philopatry to natal areas to forage. Our results have important implications for life-history research and conservation of marine turtles and may extend to other wide-ranging marine vertebrates that demonstrate natal philopatry.

  19. Training on Eastern Pacific tropical cyclones for Latin American students

    Science.gov (United States)

    Farfán, L. M.; Raga, G. B.

    2009-05-01

    Tropical cyclones are one of the most impressive atmospheric phenomena and their development in the Atlantic and Eastern Pacific basins has potential to affect several Latin-American and Caribbean countries, where human resources are limited. As part of an international research project, we are offering short courses based on the current understanding of tropical cyclones in the Eastern Pacific basin. Our main goal is to train students from higher-education institutions from various countries in Latin America. Key aspects are tropical cyclone formation and evolution, with particular emphasis on their development off the west coast of Mexico. Our approach includes lectures on tropical cyclone climatology and formation, dynamic and thermodynamic models, air-sea interaction and oceanic response, ocean waves and coastal impacts as well as variability and climate-related predictions. In particular, we use a best-track dataset issued by the United States National Hurricane Center and satellite observations to analyze convective patterns for the period 1970-2006. Case studies that resulted in landfall over northwestern Mexico are analyzed in more detail; this includes systems that developed during the 2006, 2007 and 2008 seasons. Additionally, we have organized a human-dimensions symposium to discuss socio-economic issues that are associated with the landfall of tropical cyclones. This includes coastal zone impact and flooding, the link between cyclones and water resources, the flow of weather and climate information from scientists to policy- makers, the role of emergency managers and decision makers, impact over health issues and the viewpoint of the insurance industry.

  20. Mechanisms for the cooling of the central eastern Pacific

    Science.gov (United States)

    Liu, Chunlei; Allan, Richard

    2017-04-01

    The sea surface temperature variation over the Central Eastern Pacific (CEP) controls the global mean surface temperature variation (Kosaka and Xie, 2013). The regional cooling over CEP is directly linked to the surface warming slowdown in last twenty years. It is important to understand the mechanisms of the CEP cooling in the warming climate in order to have a robust prediction of the future climate change. Previous studies showed the CEP cooling is related to the pronounced strengthening in Pacific trade winds over the past two decades, which is sufficient to account for the cooling of the CEP and a substantial slowdown in surface warming through increased subsurface ocean heat uptake in the Pacific shallow overturning cells and equatorial upwelling in the CEP (England et al., 2014). By analysing the cloud data, Zhou et al. (2016) showed the increase of the lower cloud cover (LCC) over the CEP area contributed to the cooling, resulting in positive local feedback and negative global feedback. Using the data from observations, ERA-Interim reanalysis and atmospheric climate simulations, our study shows that the increasing Latent Heat (LH) also plays an important role in the CEP cooling (Liu et al., 2015). After the sensitivity test using the bulk formula, it showed that both wind and total column water vapour content contribute to the cooling trends of the SST in CEP. The observed trends of the wind and LH in CEP also confirmed this. England et al. (2014) Recent intensification of wind-driven circulation in the Pacific and the ongoing warming hiatus, Nat. Clim. Change, 4, 222-227, doi:10.1038/nclimate2106. Kosaka, Y., and S. P. Xie (2013), Recent global-warming hiatus tied to equatorial Pacific surface cooling, Nature, 501, 403-407, doi:10.1038/nature12534. Liu et al. (2015) Combining satellite observations and reanalysis energy transports to estimate global net surface energy fluxes 1985-2012. J. Geophys. Res. , Atmospheres. ISSN 2169-8996 doi: 10.1002/2015JD

  1. Genetic variation in blue whales in the eastern pacific: implication for taxonomy and use of common wintering grounds.

    Science.gov (United States)

    Leduc, R G; Archer, F I; Lang, A R; Martien, K K; Hancock-Hanser, B; Torres-Florez, J P; Hucke-Gaete, R; Rosenbaum, H C; van Waerebeek, K; Brownell, R L; Taylor, B L

    2017-02-01

    Many aspects of blue whale biology are poorly understood. Some of the gaps in our knowledge, such as those regarding their basic taxonomy and seasonal movements, directly affect our ability to monitor and manage blue whale populations. As a step towards filling in some of these gaps, microsatellite and mtDNA sequence analyses were conducted on blue whale samples from the Southern Hemisphere, the eastern tropical Pacific (ETP) and the northeast Pacific. The results indicate that the ETP is differentially used by blue whales from the northern and southern eastern Pacific, with the former showing stronger affinity to the region off Central America known as the Costa Rican Dome, and the latter favouring the waters of Peru and Ecuador. Although the pattern of genetic variation throughout the Southern Hemisphere is compatible with the recently proposed subspecies status of Chilean blue whales, some discrepancies remain between catch lengths and lengths from aerial photography, and not all blue whales in Chilean waters can be assumed to be of this type. Also, the range of the proposed Chilean subspecies, which extends to the Galapagos region of the ETP, at least seasonally, perhaps should include the Costa Rican Dome and the eastern North Pacific as well. © 2016 John Wiley & Sons Ltd.

  2. Synchronous seasonal change in fin whale song in the North Pacific.

    Directory of Open Access Journals (Sweden)

    Erin M Oleson

    Full Text Available Fin whale (Balaenoptera physalus song consists of down-swept pulses arranged into stereotypic sequences that can be characterized according to the interval between successive pulses. As in blue (B. musculus and humpback whales (Megaptera novaeangliae, these song sequences may be geographically distinct and may correlate with population boundaries in some regions. We measured inter-pulse intervals of fin whale songs within year-round acoustic datasets collected between 2000 and 2006 in three regions of the eastern North Pacific: Southern California, the Bering Sea, and Hawaii. A distinctive song type that was recorded in all three regions is characterized by singlet and doublet inter-pulse intervals that increase seasonally, then annually reset to the same shorter intervals at the beginning of each season. This song type was recorded in the Bering Sea and off Southern California from September through May and off Hawaii from December through April, with the song interval generally synchronized across all monitoring locations. The broad geographic and seasonal occurrence of this particular fin whale song type may represent a single population broadly distributed throughout the eastern Pacific with no clear seasonal migratory pattern. Previous studies attempting to infer population structure of fin whales in the North Pacific using synchronous individual song samples have been unsuccessful, likely because they did not account for the seasonal lengthening in song intervals observed here.

  3. Synchronous Seasonal Change in Fin Whale Song in the North Pacific

    Science.gov (United States)

    Oleson, Erin M.; Širović, Ana; Bayless, Alexandra R.; Hildebrand, John A.

    2014-01-01

    Fin whale (Balaenoptera physalus) song consists of down-swept pulses arranged into stereotypic sequences that can be characterized according to the interval between successive pulses. As in blue (B. musculus) and humpback whales (Megaptera novaeangliae), these song sequences may be geographically distinct and may correlate with population boundaries in some regions. We measured inter-pulse intervals of fin whale songs within year-round acoustic datasets collected between 2000 and 2006 in three regions of the eastern North Pacific: Southern California, the Bering Sea, and Hawaii. A distinctive song type that was recorded in all three regions is characterized by singlet and doublet inter-pulse intervals that increase seasonally, then annually reset to the same shorter intervals at the beginning of each season. This song type was recorded in the Bering Sea and off Southern California from September through May and off Hawaii from December through April, with the song interval generally synchronized across all monitoring locations. The broad geographic and seasonal occurrence of this particular fin whale song type may represent a single population broadly distributed throughout the eastern Pacific with no clear seasonal migratory pattern. Previous studies attempting to infer population structure of fin whales in the North Pacific using synchronous individual song samples have been unsuccessful, likely because they did not account for the seasonal lengthening in song intervals observed here. PMID:25521493

  4. Clipperton Atoll (eastern Pacific): oceanography, geomorphology, reef-building coral ecology and biogeography

    Science.gov (United States)

    Glynn, P. W.; Veron, J. E. N.; Wellington, G. M.

    1996-06-01

    Coral reef geomorphology and community composition were investigated in the tropical northeastern Pacific during April 1994. Three areas were surveyed in the Revillagigedo Islands (Mexico), and an intensive study was conducted on Clipperton Atoll (1,300 km SW of Acapulco), including macro-scale surface circulation, sea surface temperature (SST) climatology, geomorphology, coral community structure, zonation, and biogeography. Satellite-tracked drifter buoys from 1979 1993 demonstrated complex patterns of surface circulation with dominantly easterly flow (North Equatorial Counter Current, NECC), but also westerly currents (South Equatorial Current, SEC) that could transport propagules to Clipperton from both central and eastern Pacific regions. The northernmost latitude reached by the NECC is not influenced by El Niño-Southern Oscillation (ENSO) events, but easterly flow velocity evidently is accelerated at such times. Maximum NECC flow rates indicate that the eastern Pacific barrier can be bridged in 60 to 120 days. SST anomalies at Clipperton occur during ENSO events and were greater at Clipperton in 1987 than during 1982 1983. Shallow (15 18 m)and deep (50 58 m) terraces are present around most of Clipperton, probably representing Modern and late Pleistocene sea level stands. Although Clipperton is a well developed atoll with high coral cover, the reef-building fauna is depauperate, consisting of only 7 species of scleractinian corals belonging to the genera Pocillopora, Porites, Pavona and Leptoseris, and 1 species of hydrocoral in the genus Millepora. The identities of the one Pocilpopora species and one of the two Porites species are still unknown. Two of the remaining scleractinians ( Pavona minuta, Leptoseris scabra) and the hydrocoral ( Millepora exaesa), all formerly known from central and western Pacific localities, represent new eastern Pacific records. Scleractinian corals predominate (10 100% cover) over insular shelf depths of 8 to 60m, and crustose

  5. Circulation characteristics of persistent cold spells in central-eastern North America

    Science.gov (United States)

    Li, Zhenhua; Manson, Alan H.; Li, Yanping; Meek, Chris

    2017-02-01

    The circulation patterns of persistent cold weather spells with durations longer than 10 days in central-eastern North America (United States and Canada; 32°-52°N, 95°-65°W) are investigated by using NCEP reanalysis data from 1948 to 2014. The criteria for the persistent cold spells are: (1) three-day averaged temperature anomalies for the regional average over the central-eastern United States and Canada must be below the 10th percentile, and (2) such extreme cold spells must last at least 10 days. The circulation patterns associated with these cold spells are examined to find the common signals of these events. The circulation anomaly patterns of these cold spells are categorized based on the El Niño-Southern Oscillation, Arctic Oscillation (AO), and other climate indices. The atmospheric circulation patterns that favor the cold spells are identified through composites of geopotential height maps for the cold spells. Negative AO phases favor persistent cold spells. Phases of sea surface temperature (SST) modes that are associated with warm SSTs in the eastern extratropical Pacific also favor persistent cold events in the study region. Stratospheric polar vortex breakdown alone is not a good predictor for the regional extreme cold spells in central-eastern North America. The meridional dispersions of quasi-stationary Rossby waves in the Pacific-North America sector in terms of cut-off zonal wavenumber modulated by background flow are analyzed to provide insight into the difference in evolution of the cold spells under different mean AO phases. The waveguide for AO > 1 is in a narrow latitudinal band centered on 40°N, whereas the waveguide for AO <-1 is in a broader latitudinal band from 40° to 65°N. The circulation patterns and lower boundary conditions favorable for persistent cold spells identified by this study can be a stepping-stone for improving winter subseasonal forecasting in North America.

  6. Western North Pacific Typhoons with Concentric Eyewalls

    Science.gov (United States)

    2009-04-19

    Pacific CE typhoons between 1997 and 2006. Section 2 describes the data, the analysis method, and the clima - tology. The results regarding the...Willoughby, H. E., 1990: Temporal changes of the primary circu- lation of tropical cyclones. J. Atmos. Sci., 47, 242–264. 3770 M O N T H L Y W E A T H E R R E V I E W VOLUME 137

  7. 77 FR 59901 - North Pacific Fishery Management Council; Public Meeting

    Science.gov (United States)

    2012-10-01

    ... potential management measures, using the status quo management measures of one fish less than 45 inches or... National Oceanic and Atmospheric Administration RIN 0648-XC259 North Pacific Fishery Management Council... Management Council (Council) Charter Management Implementation Committee will convene via a conference...

  8. 78 FR 70018 - North Pacific Fishery Management Council; Public Meeting

    Science.gov (United States)

    2013-11-22

    ... fish with a maximum size limit; and (4) Status quo management of one fish less than 45 inches or greater than 68 inches. For Regulatory Area 3A: (1) Status quo management of a bag limit of two fish, with... National Oceanic and Atmospheric Administration RIN 0648-XC990 North Pacific Fishery Management...

  9. 75 FR 35443 - North Pacific Fishery Management Council; Public Meeting

    Science.gov (United States)

    2010-06-22

    ... National Oceanic and Atmospheric Administration RIN 0648-XX01 North Pacific Fishery Management Council... Management Council's Scientific and Statistical Committee (SSC), and Groundfish Plan Team members will hold a... determining annual catch limits (ACLs) for Tier 6 groundfish stocks. See SUPPLEMENTARY INFORMATION. DATES:...

  10. 75 FR 20985 - North Pacific Fishery Management Council; Public Meeting

    Science.gov (United States)

    2010-04-22

    ..., Girdwood, AK, Room Columbia A - May 10-13 and Portage Board Room - May 14. Council address: North Pacific... presentations on patterns of larval snow crab and a snow crab spatial model, review draft stock assessments and... revised Annual Catch Limits and Snow crab rebuilding plan analysis and provide recommendations;...

  11. North Pacific Process Study (JGOFS) (NODC Accession 0001873)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This NPPS Data Set is comprised of JGOFS data set obtained during the JGOFS NPPS as well as the JGOFS related data sets in the North Pacific. All of these data were...

  12. 78 FR 16660 - North Pacific Fishery Management Council; Public Meeting

    Science.gov (United States)

    2013-03-18

    ...; Public Meeting AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric... Hilton Hotel, Dillingham/Katmai Room, 500 West 3rd Avenue, Anchorage, AK. Council address: North Pacific... CONTACT: Diana Evans, Council staff, telephone: (907) 271-2809. ] SUPPLEMENTARY INFORMATION: The...

  13. Conservation of native Pacific trout diversity in Western North America

    Science.gov (United States)

    Brooke E. Penaluna; Alicia Abadía-Cardoso; Jason B. Dunham; Francisco J. García-Dé León; Robert E. Gresswell; Arturo Ruiz Luna; Eric B. Taylor; Bradley B. Shepard; Robert Al-Chokhachy; Clint C. Muhlfeld; Kevin R. Bestgen; Kevin Rogers; Marco A. Escalante; Ernest R. Keeley; Gabriel M. Temple; Jack E. Williams; Kathleen R. Matthews; Ron Pierce; Richard L. Mayden; Ryan P. Kovach; John Carlos Garza; Kurt D. Fausch

    2016-01-01

    Pacific trout Oncorhynchus spp. in western North America are strongly valued in ecological, socioeconomic, and cultural views, and have been the subject of substantial research and conservation efforts. Despite this, the understanding of their evolutionary histories, overall diversity, and challenges to their conservation is incomplete. We review...

  14. REE and (э)Nd of clay fractions in sediments from the eastern Pacific Ocean: Evidence for clay sources

    Institute of Scientific and Technical Information of China (English)

    LIU Jihua; SHI Xuefa; CHEN Lirong; HUANG Yongyang; WANG Yinxi; CUI Yingchun; BU Wenrui

    2005-01-01

    Clay fractions in the non-calcareous surface sediments from the eastern Pacific were analyzed for clay minerals, REE and 143Nd/144Nd. Montmorillonite/illite ratio (M/I ratio), total REE contents ((REE), LREE/HREE ratio and cerium anomaly (бCe) may effectively indicate the genesis of clay minerals. Clay fractions with M/I ratio >1, бCe (0.85, (REE (400 μg/g, LREE/HREE ratio (4, and REE patterns similar to those of pelagic sediments are terrigenous and autogenetic mixed clay fractions and contain more autogenetic montmorillonite. Clay fractions with M/I ratio <1, бCe=0.86 to 1.5, ΣREE=200 to 350 μg/g, LREE/HREE ratio (6 and REE distribution patterns similar to that of China loess are identified as terrigenous clay fraction. The 143Nd/144Nd ratios or (э)Nd values of clay fractions inherit the features of terrigenous sources of clay minerals. Clay fractions are divided into 4 types according to (э)Nd values. Terrigenous clay minerals of type I with the (э)Nd values of -8 to -6 originate mainly from North American fluvial deposits. Those of type II with the (э)Nd values of -9 to -7 are mainly from the East Asia and North American fluvial deposits. Those of type III with (э)Nd values of -6 to -3 could come from the central and eastern Pacific volcanic islands. Those of type IV with (э)Nd values of -13 to -12 may be from East Asia eolian. The terrigenous and autogenetic mixed clay fractions show patchy distributions, indicating that there are volcanic or hot-spot activities in the eastern Pacific plate, while the terrigenous clay fractions cover a large part of the study area, proving that the terrigenous clay minerals are dominant in the eastern Pacific.

  15. Shifting Pacific storm tracks as stressors to ecosystems of western North America.

    Science.gov (United States)

    Dannenberg, Matthew P; Wise, Erika K

    2017-05-02

    Much of the precipitation delivered to western North America arrives during the cool season via midlatitude Pacific storm tracks, which may experience future shifts in response to climate change. Here, we assess the sensitivity of the hydroclimate and ecosystems of western North America to the latitudinal position of cool-season Pacific storm tracks. We calculated correlations between storm track variability and three hydroclimatic variables: gridded cool-season standardized precipitation-evapotranspiration index, April snow water equivalent, and water year streamflow from a network of USGS stream gauges. To assess how historical storm track variability affected ecosystem processes, we derived forest growth estimates from a large network of tree-ring widths and land surface phenology and wildfire estimates from remote sensing. From 1980 to 2014, cool-season storm tracks entered western North America between approximately 41°N and 53°N. Cool-season moisture supply and snowpack responded strongly to storm track position, with positive correlations to storm track latitude in eastern Alaska and northwestern Canada but negative correlations in the northwestern U.S. Ecosystems of the western United States were greener and more productive following winters with south-shifted storm tracks, while Canadian ecosystems were greener in years when the cool-season storm track was shifted to the north. On average, larger areas of the northwestern United States were burned by moderate to high severity wildfires when storm tracks were displaced north, and the average burn area per fire also tended to be higher in years with north-shifted storm tracks. These results suggest that projected shifts of Pacific storm tracks over the 21st century would likely alter hydroclimatic and ecological regimes in western North America, particularly in the northwestern United States, where moisture supply and ecosystem processes are highly sensitive to the position of cool-season storm tracks.

  16. 78 FR 4835 - Endangered and Threatened Species; Recovery Plan for the North Pacific Right Whale

    Science.gov (United States)

    2013-01-23

    ... Plan for the North Pacific Right Whale AGENCY: National Marine Fisheries Service, National Oceanic and... Plan (Plan) for the North Pacific right whale (Eubalaena japonica). NMFS is soliciting review and... West Highway, Silver Spring, MD 20910, Attn: North Pacific Right Whale Recovery Plan. Instructions:...

  17. ON THE RELATIONSHIPS BETWEEN THE SUMMER RAINFALL IN CHINA AND THE ATMOSPHERIC HEAT SOURCES OVER THE EASTERN TIBETAN PLATEAU AND THE WESTERN PACIFIC WARM POOL

    Institute of Scientific and Technical Information of China (English)

    简茂球; 罗会邦; 乔云亭

    2004-01-01

    The relationships between the summer rainfall in China and the atmospheric heat sources over the eastern Tibetan Plateau and the western Pacific warm pool were analyzed comparatively, using the NCEP/NCAR reanalysis daily data. The strong (weak) heat source in summer over the eastern Tibetan Plateau will lead to abundant (scarce) summer rainfall in the Yangtze River basin, and scarce/abundant summer rainfall in the eastern part of Southern China. While the strong (weak) heat source in summer over the western Pacific warm pool will lead to another pattern of abundant (scarce) summer rainfall in the middle-lower reaches of the Yangtze River and scarce (abundant) summer rainfall in Southern China and in the region of northern Jiangsu to southern Shandong. Comparatively, the heat source over the eastern Tibetan Plateau affects a larger area of summer rainfall than the heat source over the western Pacific. In both cases of the heat source anomalies over the eastern Tibetan Plateau and over the western Pacific, there exist EAP-like teleconnection patterns in East Asia. The summer rainfall in China is influenced directly by the abnormal vertical motion, which is related closely to the abnormal heat sources in the atmosphere. The ridge line of the western Pacific High locates far south (north) in summer in the case of strong (weak) heat sources over the two areas mentioned above.

  18. Increase in water column denitrification during the deglaciation controlled by oxygen demand in the eastern equatorial Pacific

    Directory of Open Access Journals (Sweden)

    P. Martinez

    2009-05-01

    Full Text Available Here we present organic export production and isotopic nitrogen results over the last 30 000 years from one core localized off Costa Rica (ODP Site 1242 on the leading edge of the oxygen minimum zone of the Eastern Tropical North Pacific. Marine export production reveals glacial-interglacial variations with low organic matter (total organic carbon and total nitrogen contents during warm intervals, twice more during cold episodes and double peaked maximum during the deglaciation, between ~15.5–18.5 and 11–13 ka BP. When this new export production record is compared with four nearby cores localized within the Eastern Pacific along the Equatorial divergence, a good agreement between all the cores is observed, with the major feature being a maximum of export during the early deglaciation. As for export production, water-column denitrification represented by sedimentary δ15N records along the Eastern tropical North and South Pacific between 15° N and 36° S is coherent as well over the last deglaciation period. The whole isotopic nitrogen profiles indicate that denitrification increased abruptly at 19 ka BP to a maximum during the early deglaciation, confirming a typical Antarctic timing. It is proposed that the increase in export production and then in subsurface oxygen demand lead to an intensification of water-column denitrification within the oxygen minimum zones in the easternmost Pacific at the time of the last deglaciation. The triggering mechanism would have been primarily linked to an increase in preformed nutrients contents feeding the Equatorial Undercurrent driven by the resumption of overturning in the Southern Ocean and the return of nutrients from the deep ocean to the sea-surface. An increase in equatorial wind-driven upwelling of sub-surface nutrient-rich waters could have played the role of an amplifier.

  19. Speciation of Fe in the Eastern North Atlantic Ocean

    NARCIS (Netherlands)

    Thuroczy, C-E; Gerringa, L. J. A.; Klunder, M. B.; Middag, R.; Laan, P.; Timmermans, K. R.; de Baar, H. J. W.

    2010-01-01

    In the Eastern North Atlantic Ocean iron (Fe) speciation was investigated in three size fractions the dissolvable from unfiltered samples the dissolved fraction (0 2 mu m) fraction were unsaturated with Fe with respect to the dissolved fraction thus these waters had a scavenging potential Crown

  20. Scale interaction between typhoons and the North Pacific subtropical high and associated remote effects during the Baiu/Meiyu season

    Science.gov (United States)

    Hirata, Hidetaka; Kawamura, Ryuichi

    2014-05-01

    The interaction between typhoons and the North Pacific subtropical high and the associated remote impact on East Asian and North Pacific anomalous weather during the Baiu/Meiyu season have been investigated using the Japanese long-term Reanalysis project data aided by the Japan Meteorological Agency Climate Data Assimilation System. The typhoons that appeared in July have been categorized into two primary tracks, the Hainan Island course (HC) and the Okinawa Island course (OC). A typhoon gives rise to negative absolute vorticity advection along its eastern periphery, which locally reinforces the western ridge of the North Pacific subtropical high, whereas the resultant anomalous high stimulates the westward (northward) migration of the HC (OC) typhoon through its combination with the background flow. A combined effect of the typhoon and its induced anomalous anticyclonic circulation increases the transportation of moisture into the Baiu/Meiyu frontal zone in the vicinity of Japan. Over the East China Sea and the Sea of Japan, northward or northeastward moisture flux is pronounced along the western periphery of the typhoon-induced anticyclonic circulation anomaly in the HC category, triggering heavy rainfall on central Japan's Sea of Japan coast. Similar remote effects also operate in the OC category, which is responsible for the occurrence of extremely heavy rainfall along the Pacific coast of western Japan. When an OC typhoon approaches the Asian jet, it is capable of giving rise to anticyclonic vorticity within the jet, leading to the downstream development of stationary Rossby wave packets via the North Pacific waveguide.

  1. Modulation of western North Pacific tropical cyclone activity by the Atlantic Meridional Mode

    Science.gov (United States)

    Zhang, Wei; Vecchi, Gabriel A.; Villarini, Gabriele; Murakami, Hiroyuki; Rosati, Anthony; Yang, Xiaosong; Jia, Liwei; Zeng, Fanrong

    2017-01-01

    This study examines the year-to-year modulation of the western North Pacific (WNP) tropical cyclones (TC) activity by the Atlantic Meridional Mode (AMM) using both observations and the Geophysical Fluid Dynamics Laboratory Forecast-oriented Low Ocean Resolution Version of CM2.5 (FLOR) global coupled model. 1. The positive (negative) AMM phase suppresses (enhances) WNP TC activity in observations. The anomalous occurrence of WNP TCs results mainly from changes in TC genesis in the southeastern part of the WNP. 2. The observed responses of WNP TC activity to the AMM are connected to the anomalous zonal vertical wind shear (ZVWS) caused by AMM-induced changes to the Walker circulation. During the positive AMM phase, the warming in the North Atlantic induces strong descending flow in the tropical eastern and central Pacific, which intensifies the Walker cell in the WNP. The intensified Walker cell is responsible for the suppressed (enhanced) TC genesis in the eastern (western) part of the WNP by strengthening (weakening) ZVWS. 3. The observed WNPTC-AMM linkage is examined by the long-term control and idealized perturbations experiment with FLOR-FA. A suite of sensitivity experiments strongly corroborate the observed WNPTC-AMM linkage and underlying physical mechanisms.

  2. Fluctuation in Ommastrephe bartrami yield in the North Pacific

    Institute of Scientific and Technical Information of China (English)

    ZHENG Rui; CHEN Ge

    2008-01-01

    The fluctuation in Ommastrephe bartrami yield from 1995 to 2001 in the North Pacific was shown obvious, on which this study was conducted using data of sea surface temperature (SST), chlorophyll-a (chl-a) and statistical production. The study shows that, cool water and low food abundance caused by abnormal Kuroshio resulted in the reduction in abundance of O. bartrami, which was worsened by excessive catch and the unawareness to local fishery resources protection.

  3. North Pacific Acoustic Laboratory and Deep Water Acoustics

    Science.gov (United States)

    2016-10-27

    Acoustic Lab and Deep Water Acoustics” Encl: (1) Final Technical Report for Subject Grant (2) SF298 for Enclosure Enclosure (1) is the Final...North Pacific Acoustic Laboratory and Deep Water Acoustics Final Report PI James A. Mercer Applied Physics Laboratory...During FY16 the primary effort has been working on manuscripts as summarized below: 1) A test of deep water Rytov theory at 284 Hz and 107 km in

  4. Vertical distribution of (236)U in the North Pacific Ocean.

    Science.gov (United States)

    Eigl, R; Steier, P; Sakata, K; Sakaguchi, A

    2017-04-01

    The first extensive study on (236)U in the North Pacific Ocean has been conducted. The vertical distribution of (236)U/(238)U isotopic ratios and the (236)U concentrations were analysed on seven depth profiles, and large variations with depth were found. The range of (236)U/(238)U isotopic ratios was from (0.09 ± 0.03) × 10(-10) to (14.1 ± 2.2) × 10(-10), which corresponds to (236)U concentrations of (0.69 ± 0.24) × 10(5) atoms/kg and (119 ± 21) × 10(5) atoms/kg, respectively. The variations in (236)U concentrations could mainly be attributed to the different water masses in the North Pacific Ocean and their formation processes. Uranium-236 inventories on the water column of each sampling station were calculated and varied between (3.89 ± 0.08) × 10(12) atoms/m(2) and (7.03 ± 0.50) × 10(12) atoms/m(2), which is lower than in former studies on comparable latitudes in the North Atlantic Ocean and the Sea of Japan. The low inventories of (236)U found for the North Pacific Ocean in this study can be explained by the lack of additional input sources of artificial radionuclides, apart from global and regional/local fallout. This study expands the use of (236)U as oceanographic circulation tracer to yet another ocean basin and shows that this isotope can be used for tracing circulation patterns of water masses in the Pacific Ocean. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Rising climate variability and synchrony in North Pacific ecosystems

    Science.gov (United States)

    Black, Bryan

    2017-04-01

    Rising climate variability and synchrony in North Pacific ecosystems Evidence is growing that climate variability of the northeast Pacific Ocean has increased over the last century, culminating in such events as the record-breaking El Niño years 1983, 1998, and 2016 and the unusually persistent 2014/15 North Pacific Ocean heat wave known as "The Blob." Of particular concern is that rising variability could increase synchrony within and among North Pacific ecosystems, which could reduce the diversity of biological responses to climate (i.e. the "portfolio effect"), diminish resilience, and leave populations more prone to extirpation. To test this phenomenon, we use a network of multidecadal fish otolith growth-increment chronologies that were strongly correlated to records of winter (Jan-Mar) sea level. These biological and physical datasets spanned the California Current through the Gulf of Alaska. Synchrony was quantified as directional changes in running (31-year window) mean pairwise correlation within sea level and then within otolith time series. Synchrony in winter sea level at the nine stations with the longest records has increased by more than 40% over the 1950-2015 interval. Likewise, synchrony among the eight longest otolith chronologies has increased more than 100% over a comparable time period. These directional changes in synchrony are highly unlikely due to chance alone, as confirmed by comparing trends in observed data to those in simulated data (n = 10,000 iterations) with time series of identical number, length, and autocorrelation. Ultimately, this trend in rising synchrony may be linked to increased impacts of the El Niño Southern Oscillation (ENSO) on mid-latitude ecosystems of North America, and may therefore reflect a much broader, global-scale signature.

  6. Indicators of Marine Pollution in the North Pacific Ocean.

    Science.gov (United States)

    Brown, Tanya M; Takada, Hideshige

    2017-08-01

    The complex nature of ocean pollution underscores the utility in identifying and characterizing a limited number of "indicators" that enables scientists and managers to track trends over space and time. This paper introduces a special issue on indicators of marine pollution in the North Pacific Ocean and builds on a scientific session that was held at the North Pacific Marine Science Organization. The special issue highlights studies using a variety of indicators to provide insight into the identification of legacy and emerging contaminants, the ranking of priority pollutants from various sources, and the effects of contaminants on ecosystem health in the North Pacific Ocean. Examples include the use of mussels to illustrate spatial and temporal trends of a number of contaminants following the 2011 tsunami in Japan, the use of molecular marker (linear alkylbenzenes, hopanes, and polycyclic aromatic hydrocarbons) profiles to identify pollution sources, and the use of plastic resin pellets to illustrate spatial trends of petroleum pollution around the world. Stable isotopes were used to strengthen the utility of the Glaucous-winged gull (Larus glaucescens) as an indicator of marine pollution. Examples also demonstrate the development and application of biomarker approaches, including gene transcripts, oxidative stress, estradiol, hatchability, and respiration and swimming behavior abnormalities, as a function of exposure to polychlorinated biphenyls, sulfur-diesel, Pinghu crude oil, galaxolide and antifouling biocides. We provide a brief review of indicators of marine pollution, identify research gaps, and summarize key findings from the articles published within the issue. This special issue represents the first compilation of research pertaining to marine pollution indicators in the North Pacific Ocean and provides guidance to inform mitigation and monitoring efforts of contaminants in the region.

  7. Heat and salt transport throughout the North Pacific Ocean

    Science.gov (United States)

    Yang, Lina; Yuan, Dongliang

    2016-11-01

    Absolute geostrophic currents in the North Pacific Ocean are calculated using the P-vector method and gridded Argo profiling data from January 2004 to December 2012. Three-dimensional structures and seasonal variability of meridional heat transport (MHT) and meridional salt transport (MST) are analyzed. The results show that geostrophic and Ekman components are generally opposite in sign, with the southward geostrophic component dominating in the subtropics and the northward Ekman component dominating in the tropics. In combination with the net surface heat flux and the MST through the Bering Strait, the MHT and MST of the western boundary currents (WBCs) are estimated for the first time. The results suggest that the WBCs are of great importance in maintaining the heat and salt balance of the North Pacific. The total interior MHT and MST in the tropics show nearly the same seasonal variability as that of the Ekman components, consistent with the variability of zonal wind stress. The geostrophic MHT in the tropics is mainly concentrated in the upper layers, while MST with large amplitude and annual variation can extend much deeper. This suggests that shallow processes dominate MHT in the North Pacific, while MST can be affected by deep ocean circulation. In the extratropical ocean, both MHT and MST are weak. However, there is relatively large and irregular seasonal variability of geostrophic MST, suggesting the importance of the geostrophic circulation in the MST of that area.

  8. Coralline alga reveals first marine record of subarctic North Pacific climate change

    Science.gov (United States)

    Halfar, J.; Steneck, R.; Schone, B.; Moore, G.W.K.; Joachimski, M.; Kronz, A.; Fietzke, J.; Estes, James

    2007-01-01

    While recent changes in subarctic North Pacific climate had dramatic effects on ecosystems and fishery yields, past climate dynamics and teleconnection patterns are poorly understood due to the absence of century-long high-resolution marine records. We present the first 117-year long annually resolved marine climate history from the western Bering Sea/Aleutian Island region using information contained in the calcitic skeleton of the long-lived crustose coralline red alga Clathromorphum nereostratum, a previously unused climate archive. The skeletal ??18O-time series indicates significant warming and/or freshening of surface waters after the middle of the 20th century. Furthermore, the time series is spatiotemporally correlated with Pacific Decadal Oscillation (PDO) and tropical El Nio??-Southern Oscillation (ENSO) indices. Even though the western Bering Sea/Aleutian Island region is believed to be outside the area of significant marine response to ENSO, we propose that an ENSO signal is transmitted via the Alaskan Stream from the Eastern North Pacific, a region of known ENSO teleconnections. Copyright 2007 by the American Geophysical Union.

  9. The ecology of xenophyophores (Protista) on eastern Pacific seamounts

    Science.gov (United States)

    Levin, Lisa A.; Thomas, Cynthia L.

    1988-12-01

    Large, agglutinating protozoans of the class Xenophyophorea are the dominant epifaunal organisms on soft and hard substrates of many bathyal seamounts in the eastern Pacific Ocean off Mexico. Observations made with the submersible Alvin and remotely towed camera sleds on 17 seamounts at 31°, 20°, 13° and 10°N revealed more than ten distinct xenophyophore test morphologies. Most of these appear to represent previously undescribed species. Reticulate forms are numerically dominant at 20°, 13° and 10°N. Xenophyophore abundances increase with decreasing latitude, being rare at 30°N, present at densities of 0.1-1.0 m -2 at 20° and 13°N and often exceeding 1.0 m -2 at 10°N, occasionally reaching 10-18 m -2. Highest concentrations are observed on caldera floors near the base of steep caldera walls, at depths between 1700 and 2500 m. Most individuals select sand-size pelagic foraminiferan tests (63-500 μm) and exclude pebble, silt and clay-size particles for test construction. Xenophyophore on seamounts modify the structure of metazoan communities and may play a role in maintenance of infaunal diversity. Twenty-seven xenophyophore tests were found to provide habitat for 16 major macrofaunal taxa (152 individuals) and three meiofaunal taxa (333 individuals). The presence of xenophyophores also enhances the abundance of isopods, tanaids, ophiuroids, nematodes and harpacticoid copepods dwelling in sediments surrounding the tests. Mobile megafauna are attracted to sediment beneath and adjacent to xenophyophores. We suggest that xenophyophores, which are abundant on many topographic features in deep water (e.g. guyots, trenches, canyons and continental slopes), are a functionally important component of deep-sea benthic communities and require further autecological and synecological investigation.

  10. Summertime Subtropical Countercurrent on isopycnals in the western North Pacific

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Circulations on isopycnals (σrθ) in the western North Pacific were investigated by using P-vector method;the data were taken from the U.S. Navy's climatological temperature and salinity dataset (public domain) with 1/2°×1/2° resolution. Results not only show the main circulation systems on isopycnals in the western North Pacific such as the North Equatorial Current (NEC), Kuroshio and Kuroshio Countercurrent, but also reveal the Subtropical Countercurrent (STCC) clearly. In this note we pay attention to discussing the distribution of STCC in summer (in June).The STCC flows eastward along a winding road; on shallow isopycnals, the STCC originates from the area east of Bashi Strait at about 122.5°E; with the isopycnals increasing, the origin and flow core of STCC move to north and east, but the main part of STCC is still between 18° and 23.5°N, i.e.near the Tropic of Cancer. There exists STCC on all isopycnals between the sea surface and 25.8 σθThe current vectors of STCC on isopycnais are shown for the first time, and the distribution of the potential vorticity indicates that STCC is just overlying the southern boundary of the Subtropical Mode Water (STMW).``

  11. Holocene Pacific North American plate interaction in southern Alaska: Implications for the Yakataga seismic gap

    Science.gov (United States)

    Lahr, John C.; Plafker, George

    1980-10-01

    The St. Elias, Alaska, earthquake (magnitude 7.1 Ms) on February 28, 1979, occurred along the complex Pacific North American plate boundary between Yakutat Bay and Prince William Sound, rupturing only a fraction of the seismic gap identified in that region. To aid in evaluating the potential for, and likely site of, a future earthquake occurring in the remainder of the gap, we have formulated a kinematic model of neotectonic deformation in southern Alaska from available geologic and seismic data. In this model the part of the North American plate bordering on the Gulf of Alaska is divided into three subblocks, which are partially coupled to the Pacific plate. On the basis of the model, the gap-filling rupture or ruptures would most likely be along the north-dipping thrust faults of the Pamplona zone between Icy Bay and the eastern end of the Aleutian Trench. If the accumulated strain of 3.8 m postulated for this region were released suddenly in one event involving the remainder of the gap, the result would be an earthquake as large as magnitude 8.

  12. Holocene Pacific - North American plate interaction in southern Alaska: implications for the Yakataga seismic gap.

    Science.gov (United States)

    Lahr, J.C.; Plafker, G.

    1980-01-01

    The St. Elias, Alaska, earthquake (magnitude 7.1 MS) on February 28, 1979, occurred along the complex Pacific-North American plate boundary between Yakutat Bay and Prince William Sound, rupturing only a fraction of the seismic gap identified in that region. To aid in evaluating the potential for, and likely site of, a future earthquake occurring in the remainder of the gap, we have formulated a kinematic model of neotectonic deformation in southern Alaska from available geologic and seismic data. In this model the part of the North American plate bordering on the Gulf of Alaska is divided into three subblocks, which are partially coupled to the Pacific plate. On the basis of the model, the gap-filling rupture or ruptures would most likely be along the north-dipping thrust faults of the Pamplona zone between Icy Bay and the eastern end of the Aleutian Trench. If the accumulated strain of 3.8 m postulated for this region were released suddenly in one event involving the remainder of the gap, the result would be an earthquake as large as magnitude 8. -Authors

  13. Genetic isolation between the Western and Eastern Pacific populations of pronghorn spiny lobster Panulirus penicillatus.

    Science.gov (United States)

    Chow, Seinen; Jeffs, Andrew; Miyake, Yoichi; Konishi, Kooichi; Okazaki, Makoto; Suzuki, Nobuaki; Abdullah, Muhamad F; Imai, Hideyuki; Wakabayasi, Toshie; Sakai, Mitsuo

    2011-01-01

    The pronghorn spiny lobster, Panulirus penicillatus, is a circumtropical species which has the widest global distribution among all the species of spiny lobster, ranging throughout the entire Indo-Pacific region. Partial nucleotide sequences of mitochondrial DNA COI (1,142-1,207 bp) and 16S rDNA (535-546 bp) regions were determined for adult and phyllosoma larval samples collected from the Eastern Pacific (EP)(Galápagos Islands and its adjacent water), Central Pacific (CP)(Hawaii and Tuamotu) and the Western Pacific (WP)(Japan, Indonesia, Fiji, New Caledonia and Australia). Phylogenetic analyses revealed two distinct large clades corresponding to the geographic origin of samples (EP and CP+WP). No haplotype was shared between the two regional samples, and average nucleotide sequence divergence (Kimura's two parameter distance) between EP and CP+WP samples was 3.8±0.5% for COI and 1.0±0.4% for 16S rDNA, both of which were much larger than those within samples. The present results indicate that the Pacific population of the pronghorn spiny lobster is subdivided into two distinct populations (Eastern Pacific and Central to Western Pacific), with no gene flow between them. Although the pronghorn spiny lobster have long-lived teleplanic larvae, the vast expanse of Pacific Ocean with no islands and no shallow substrate which is known as the East Pacific Barrier appears to have isolated these two populations for a long time (c.a. 1MY).

  14. Baleen Whale Acoustic Activity in the North Pacific: Historical Analysis and Current Occurrence

    Science.gov (United States)

    2007-12-01

    whales, including the blue (Balaenoptera musculus), fin (B. physalus), sei (B. borealis), humpback ( Megaptera novaeangliae ), and North Pacific right...Research Collective Olympia, WA Julie Rivers Naval Facilities Engineering Command, Pacific Pearl Harbor, HI Jenny Marshall Naval Facilities

  15. AFSC/RACE/GAP/Conrath: Delayed discard mortality of the North Pacific giant octopus

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The majority of octopus bycatch occurs in Pacific cod pot fisheries and recent data collected by North Pacific Groundfish Observers indicate that immediate mortality...

  16. A regional scale modeling analysis of aerosol and trace gas distributions over the eastern Pacific during the INTEX-B field campaign

    Directory of Open Access Journals (Sweden)

    B. Adhikary

    2010-03-01

    Full Text Available The Sulfur Transport and dEposition Model (STEM is applied to the analysis of observations obtained during the Intercontinental Chemical Transport Experiment-Phase B (INTEX-B, conducted over the eastern Pacific Ocean during spring 2006. Predicted trace gas and aerosol distributions over the Pacific are presented and discussed in terms of transport and source region contributions. Trace species distributions show a strong west (high to east (low gradient, with the bulk of the pollutant transport over the central Pacific occurring between ~20° N and 50° N in the 2–6 km altitude range. These distributions are evaluated in the eastern Pacific by comparison with the NASA DC-8 and NSF/NCAR C-130 airborne measurements along with observations from the Mt. Bachelor (MBO surface site. Thirty different meteorological, trace gas and aerosol parameters are compared. In general the meteorological fields are better predicted than gas phase species, which in turn are better predicted than aerosol quantities. PAN is found to be significantly overpredicted over the eastern Pacific, which is attributed to uncertainties in the chemical reaction mechanisms used in current atmospheric chemistry models in general and to the specifically high PAN production in the SAPRC-99 mechanism used in the regional model. A systematic underprediction of the elevated sulfate layer in the eastern Pacific observed by the C-130 is another issue that is identified and discussed. Results from source region tagged CO simulations are used to estimate how the different source regions around the Pacific contribute to the trace gas species distributions. During this period the largest contributions were from China and from fires in South/Southeast and North Asia. For the C-130 flights, which operated off the coast of the Northwest US, the regional CO contributions range as follows: China (35%, South/Southeast Asia fires (35%, North America anthropogenic (20%, and North Asia fires (10

  17. Attributing the causes of North Pacific oxygen change

    Science.gov (United States)

    Deutsch, C.; Emerson, S.; Thompson, L.

    2004-12-01

    We investigate the variability of dissolved oxygen in the upper water column of the North Pacific using a hind cast model simulation. The model applies the biogeochemical framework of the Ocean Carbon Model Intercomparison Project (OCMIP) to an isopycnal General Circulation Model (GCM) whose circulation is forced at the surface by historical atmospheric conditions from 1948-2000. Simulated O2 changes from the 1980's to the 1990's include O2 decreases in the subpolar region, especially in the lower ventilated thermocline, and O2 increases over much of the subtropics. Both of these features are similar in pattern and magnitude to those observed along repeat transects through the subtropical and subpolar gyres [Emerson et al. 2004]. We perform a set of additional simulations designed to separate the contributions of changes in biology, ventilation, and circulation to O2 variability. We find that the direct effect of circulation variability, including a southward expansion of the subtropical gyre, is the dominant cause of O2 changes over much of the North Pacific. Variations in thermocline ventilation lead to significant O2 decreases in the Subarctic Northwest Pacific, and the impact of changes in biological export production are confined to the upper thermocline. Simulated O2 changes involve both long-term trends, such as the decreased Subarctic O2 due to reduced ventilation, as well as transient responses to short-term perturbations, many of which occurred in the 1970's.

  18. Variability in the correlation between Asian dust storms and chlorophyll a concentration from the North to Equatorial Pacific.

    Science.gov (United States)

    Tan, Sai-Chun; Yao, Xiaohong; Gao, Hui-Wang; Shi, Guang-Yu; Yue, Xu

    2013-01-01

    A long-term record of Asian dust storms showed seven high-occurrence-frequency centers in China. The intrusion of Asian dust into the downwind seas, including the China seas, the Sea of Japan, the subarctic North Pacific, the North Pacific subtropical gyre, and the western and eastern Equatorial Pacific, has been shown to add nutrients to ocean ecosystems and enhance their biological activities. To explore the relationship between the transported dust from various sources to the six seas and oceanic biological activities with different nutrient conditions, the correlation between monthly chlorophyll a concentration in each sea and monthly dust storm occurrence frequencies reaching the sea during 1997-2007 was examined in this study. No correlations were observed between dust and chlorophyll a concentration in the atmospheric deposition is commonly believed to exert less impact on coastal seas. Significant correlations existed between dust sources and many sea areas, suggesting a link between dust and chlorophyll a concentration in those seas. However, the correlation coefficients were highly variable. In general, the correlation coefficients (0.54-0.63) for the Sea of Japan were highest, except for that between the subarctic Pacific and the Taklimakan Desert, where it was as high as 0.7. For the >50 m China seas and the North Pacific subtropical gyre, the correlation coefficients were in the range 0.32-0.57. The correlation coefficients for the western and eastern Equatorial Pacific were relatively low (dust sources, the transport pathways, the dust deposition, the nutrient conditions of oceans, and the probability of dust storms reaching the seas.

  19. Multiple distant origins for green sea turtles aggregating off Gorgona Island in the Colombian eastern Pacific.

    Directory of Open Access Journals (Sweden)

    Diego F Amorocho

    Full Text Available 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.

  20. Antarctic-type blue whale calls recorded at low latitudes in the Indian and eastern Pacific Oceans

    Science.gov (United States)

    Stafford, Kathleen M.; Bohnenstiehl, DelWayne R.; Tolstoy, Maya; Chapp, Emily; Mellinger, David K.; Moore, Sue E.

    2004-10-01

    Blue whales, Balaenoptera musculus, were once abundant around the Antarctic during the austral summer, but intensive whaling during the first half of the 20th century reduced their numbers by over 99%. Although interannual variability of blue whale occurrence on the Antarctic feeding grounds was documented by whalers, little was known about where the whales spent the winter months. Antarctic blue whales produce calls that are distinct from those produced by blue whales elsewhere in the world. To investigate potential winter migratory destinations of Antarctic blue whales, we examined acoustic data for these signals from two low-latitude locales: the eastern tropical Pacific Ocean and the Indian Ocean. Antarctic-type blue whale calls were detected on hydrophones in both regions during the austral autumn and winter (May-September), with peak detections in July. Calls occurred over relatively brief periods in both oceans, suggesting that there may be only a few animals migrating so far north and/or producing calls. Antarctic blue whales appear to use both the Indian and eastern Pacific Oceans concurrently, indicating that there is not a single migratory destination. Acoustic data from the South Atlantic and from mid-latitudes in the Indian or Pacific Oceans are needed for a more global understanding of migratory patterns and destinations of Antarctic blue whales.

  1. Feeding grounds of the eastern South Pacific humpback whale population include the South Orkney Islands

    Directory of Open Access Journals (Sweden)

    Luciano Dalla Rosa

    2012-03-01

    Full Text Available This paper reports on two photo-identified humpback whales (Megaptera novaeangliae that were sighted in different years in the proximity of the South Orkney Islands, at the boundary between the Scotia and Weddell seas (60°54.5'S—46°40.4'W and 60°42.6'S—45°33'W. One of the whales had been previously sighted off Ecuador, a breeding ground for the eastern South Pacific population. The other whale was subsequently resighted in Bransfield Strait, off the western Antarctic Peninsula, a well-documented feeding ground for the same population. These matches give support to a hypothesis that the area south of the South Orkney Islands is occupied by whales from the eastern South Pacific breeding stock. Consequently, we propose 40°W as a new longitudinal boundary between the feeding grounds associated with the eastern South Pacific and western South Atlantic breeding stocks.

  2. Iron fertilisation by Asian dust influences North Pacific sardine regime shifts

    Science.gov (United States)

    Qiu, Yongsong

    2015-05-01

    Forcing factors and mechanisms underlying multidecadal variability in the production of the world's major fish stocks are one of the great mysteries of the oceans. The Japanese and California sardine are species that exhibit the regime shifts. It is shown in the present work that during two periods of frequent Asian dust events over the last 100 years, sardines on opposite sides of the Pacific Ocean only flourished under a dust-active regime. The earlier such regime that peaked in the 1930s was strong, and it brought synchronous changes in the two species that were linked to the frequency of Asian dust events. However, there is an apparent mismatch in the rise and fall of abundance between the two species in the current dust-active regime. The massive increase in Japanese sardine stock in the 1970s was related to high levels of ocean precipitation and strong winter mixing, whereas the stock collapse since 1988 has been attributed to diminished winter mixing. High levels of ocean precipitation in the western North Pacific effectively cause wet deposition of Asian dust and enhance Japanese sardine stock, whereas it reduces dust flux that can be transported to the eastern North Pacific, delaying the increase of California sardine stock. Analysis further indicates that productivity of Japanese sardine stock is jointly controlled by wet deposition of Asian dust and winter mixing, which supplies macronutrients from depth. California sardine productivity is inversely related to precipitation in the western North Pacific and is positively affected by precipitation off western North America. This indicates that Asian dust influx dominates productivity of the species because of iron-limited ocean productivity in the California sardine ranges. The analysis suggests that dust regime shifts influence shifts in sardine productivity regimes and that iron input from Asian dust during trans-Pacific transport is directly responsible. It appears that in addition to enhancing

  3. EFFECTS OF PACIFIC SSTA ON SUMMER PRECIPITATION OVER EASTERN CHINA, PART Ⅱ: NUMERICAL SIMULATIONS

    Institute of Scientific and Technical Information of China (English)

    YU Zheng-shou; SUN Zhao-bo; NI Dong-hong; ZENG Gang

    2007-01-01

    Based on an observational analysis, seven numerical experiments are designed to study the impacts of Pacific SSTA on summer precipitation over eastem China and relevant physical mechanism by NCAR CCM3. The numerical simulation results show that preceding winter SSTA in the Kuroshio region leads to summer precipitation anomaly over the Yangtze River valleys by modifying atmospheric general circulation over eastern Asia and middle-high latitude. West Pacific subtropical high is notably affected by preceding spring SSTA over the middle and east of Equator Pacific; SSTA of the central region of middle latitude in the corresponding period causes the summer rainfall anomaly over eastern China so as to trigger the atmospheric Eurasia-Pacific teleconnection pattern.

  4. Indo-Pacific sea surface temperature influences on failed consecutive rainy seasons over eastern Africa

    Science.gov (United States)

    Hoell, Andrew; Funk, Christopher C.

    2014-01-01

    Rainfall over eastern Africa (10°S–10°N; 35°E–50°E) is bimodal, with seasonal maxima during the "long rains" of March–April–May (MAM) and the "short rains" of October–November–December (OND). Below average precipitation during consecutive long and short rains seasons over eastern Africa can have devastating long-term impacts on water availability and agriculture. Here, we examine the forcing of drought during consecutive long and short rains seasons over eastern Africa by Indo-Pacific sea surface temperatures (SSTs). The forcing of eastern Africa precipitation and circulation by SSTs is tested using ten ensemble simulations of a global weather forecast model forced by 1950–2010 observed global SSTs. Since the 1980s, Indo-Pacific SSTs have forced more frequent droughts spanning consecutive long and short rains seasons over eastern Africa. The increased frequency of dry conditions is linked to warming SSTs over the Indo-west Pacific and to a lesser degree to Pacific Decadal Variability. During MAM, long-term warming of tropical west Pacific SSTs from 1950–2010 has forced statistically significant precipitation reductions over eastern Africa. The warming west Pacific SSTs have forced changes in the regional lower tropospheric circulation by weakening the Somali Jet, which has reduced moisture and rainfall over the Horn of Africa. During OND, reductions in precipitation over recent decades are oftentimes overshadowed by strong year-to-year precipitation variability forced by the Indian Ocean Dipole and the El Niño–Southern Oscillation.

  5. Indo-Pacific sea surface temperature influences on failed consecutive rainy seasons over eastern Africa

    Science.gov (United States)

    Hoell, Andrew; Funk, Chris

    2014-09-01

    Rainfall over eastern Africa (10°S-10°N; 35°E-50°E) is bimodal, with seasonal maxima during the "long rains" of March-April-May (MAM) and the "short rains" of October-November-December (OND). Below average precipitation during consecutive long and short rains seasons over eastern Africa can have devastating long-term impacts on water availability and agriculture. Here, we examine the forcing of drought during consecutive long and short rains seasons over eastern Africa by Indo-Pacific sea surface temperatures (SSTs). The forcing of eastern Africa precipitation and circulation by SSTs is tested using ten ensemble simulations of a global weather forecast model forced by 1950-2010 observed global SSTs. Since the 1980s, Indo-Pacific SSTs have forced more frequent droughts spanning consecutive long and short rains seasons over eastern Africa. The increased frequency of dry conditions is linked to warming SSTs over the Indo-west Pacific and to a lesser degree to Pacific Decadal Variability. During MAM, long-term warming of tropical west Pacific SSTs from 1950-2010 has forced statistically significant precipitation reductions over eastern Africa. The warming west Pacific SSTs have forced changes in the regional lower tropospheric circulation by weakening the Somali Jet, which has reduced moisture and rainfall over the Horn of Africa. During OND, reductions in precipitation over recent decades are oftentimes overshadowed by strong year-to-year precipitation variability forced by the Indian Ocean Dipole and the El Niño-Southern Oscillation.

  6. Taxonomy Icon Data: North Pacific right whale [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available North Pacific right whale Eubalaena japonica Chordata/Vertebrata/Mammalia/Theria/Eu...theria/Cetacea Eubalaena_japonica_L.png Eubalaena_japonica_NL.png Eubalaena_japonica_S.png Eubalaena_japonic...a_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Eubalaena+japonica&t=L http://biosciencedbc.jp/tax...onomy_icon/icon.cgi?i=Eubalaena+japonica&t=NL http://biosciencedbc.jp/taxonomy_ic...on/icon.cgi?i=Eubalaena+japonica&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Eubalaena+japonica&t=NS ...

  7. Western North Pacific tropical cyclone wind structure and structure changes

    OpenAIRE

    Fisher, Michael Robert.

    1996-01-01

    Subjective and objective analyses of near-surface winds are utilized to estimate tropical cyclone (TC) size over a region of the western North Pacific. An empirical outer wind profile assuming partial conservation of angular momentum is utilized to determine the radial extent of cyclonic winds, which may be defined as the TC size in four categories. The first method uses the radii of either 3O-kt or 35-kt wind in the Joint Typhoon Warning Center (JTWC) warnings during 1989-1994 to estimate th...

  8. Iron-rich basal sediments from the eastern equatorial pacific: Leg 16, deep sea drilling project

    Science.gov (United States)

    Cronan, D.S.; Van Andel, T. H.; Ross, Heath G.; Dinkelman, M.G.; Bennett, R.H.; Bukry, D.; Charleston, S.; Kaneps, A.; Rodolfo, K.S.; Yeats, R.S.

    1972-01-01

    Iron-rich sediments chemically similar to those forming at present on the crest of the East Pacific Rise have been found just above basement at widely separated drill sites in the eastern equatorial Pacific, including three sites of Leg 16 of the Deep Sea Drilling Project. These sediments were probably formed when the basement was at the crest of this rise and have moved to their present location as a result of sea-floor spreading.

  9. Elevated Glyoxal Concentrations over the Eastern Equatorial Pacific: A Direct Biogenic Source?

    Science.gov (United States)

    Zhang, R.; Wang, Y.; Lerot, C.

    2014-12-01

    Elevated atmospheric glyoxal (CHOCHO) was observed over the eastern equatorial Pacific by satellite and ship measurements. We investigated the source contributions through inverse modeling using GOME-2 observations (2007-2012) and the GEOS-Chem model. The observed high glyoxal to HCHO column ratio over the region indicates the potential presence of a direct source of glyoxal rather than secondary production. A bimodal seasonal cycle of glyoxal concentrations was found, providing further evidence for a biogenic origin of glyoxal emission. The estimate of the primary glyoxal emission over the eastern equatorial Pacific is 20-40Tg/yr, which is comparable to the previous estimate of the global continential glyoxal emission.

  10. Iron-binding Ligands in the Eastern Tropical South Pacific: Results from U.S. GEOTRACES Cruise GP16

    Science.gov (United States)

    Buck, K. N.; Fitzsimmons, J. N.; Sherrell, R. M.; Sohst, B. M.; Sedwick, P.; John, S.

    2016-02-01

    High-resolution depth profiles, consisting of 25-49 samples each, were collected as part of the U.S. GEOTRACES Eastern Pacific Zonal Transect (GEOTRACES cruise GP16). The organic complexation of dissolved iron in these samples, including the concentrations and conditional stability constants of iron-binding ligands, was measured by competitive ligand exchange-adsorptive cathodic stripping voltammetry using the added competitive ligand salicylaldoxime. In addition to the conventional depth profile samples for dissolved (<0.2 µm) iron-binding ligands, samples were collected for size-fractionated ligand analyses using cross flow filtration. These samples were obtained from in and around the mid-depth near-field to distal hydrothermal plume emanating from the East Pacific Rise, and allowed for iron-binding ligand analyses in the dissolved (<0.45 µm), colloidal (10 kDa to 0.45 µm) and soluble (<10 kDa) size fractions. Results from this work will be presented in the context of the few previous studies of iron-binding ligands in the South Pacific, and compared with results from the North U.S. GEOTRACES North Atlantic Transect (GEOTRACES cruise GA03).

  11. Dynamic mechanism of interannual zonal displacements of the eastern edge of the western Pacific warm pool

    Institute of Scientific and Technical Information of China (English)

    齐庆华; 张启龙; 侯一筠

    2010-01-01

    The eastern edge of the western Pacific warm pool (WPWP) in the upper layer (shallower than 50m) exhibits significant zonal displacements on interannual scale. Employing an intermediate ocean model, the dynamic mechanism for the interannual zonal displacement of the WPWP eastern edge in the upper layer is investigated by diagnosing the dynamic impacts of zonal current anomalies induced by wind, waves (Kelvin and Rossby waves), and their boundary reflections. The interannual zonal displacements of the WPWP e...

  12. North Pacific deglacial hypoxic events linked to abrupt ocean warming.

    Science.gov (United States)

    Praetorius, S K; Mix, A C; Walczak, M H; Wolhowe, M D; Addison, J A; Prahl, F G

    2015-11-19

    Marine sediments from the North Pacific document two episodes of expansion and strengthening of the subsurface oxygen minimum zone (OMZ) accompanied by seafloor hypoxia during the last deglacial transition. The mechanisms driving this hypoxia remain under debate. We present a new high-resolution alkenone palaeotemperature reconstruction from the Gulf of Alaska that reveals two abrupt warming events of 4-5 degrees Celsius at the onset of the Bølling and Holocene intervals that coincide with sudden shifts to hypoxia at intermediate depths. The presence of diatomaceous laminations and hypoxia-tolerant benthic foraminiferal species, peaks in redox-sensitive trace metals, and enhanced (15)N/(14)N ratio of organic matter, collectively suggest association with high export production. A decrease in (18)O/(16)O values of benthic foraminifera accompanying the most severe deoxygenation event indicates subsurface warming of up to about 2 degrees Celsius. We infer that abrupt warming triggered expansion of the North Pacific OMZ through reduced oxygen solubility and increased marine productivity via physiological effects; following initiation of hypoxia, remobilization of iron from hypoxic sediments could have provided a positive feedback on ocean deoxygenation through increased nutrient utilization and carbon export. Such a biogeochemical amplification process implies high sensitivity of OMZ expansion to warming.

  13. Wave speed structure of the eastern North American margin

    Science.gov (United States)

    Savage, B.; Covellone, B. M.; Shen, Y.

    2017-02-01

    The eastern North American margin (ENAM) is the result of nearly a billion years of continental collision and rifting. To the west of this margin lies thick continental lithosphere of the North American craton, and to the east is oceanic lithosphere in the Atlantic. The substantial changes in lithosphere thickness at this boundary are thought to drive asthenosphere upwelling along the edge of the continent. Through iterative, full-waveform, ambient noise tomography, we observe a heterogeneous low wave speed margin along the continent in the upper mantle. Multiple low wave speed features imaged within the margin are consistent with asthenospeheric upwelling due to edge-driven convection. Also within the margin are high wave speed anomalies that maybe the remnants of eclogitic delamination of the Appalachian crustal root, which contribute to convection at the margin. Edge driven, small-scale convection keeps the margin weak and thus controls the large scale plate tectonic patterns and the crustal deformation. The imaged mantle wave speed anomalies, interpreted as edge-driven convection, correlate with and may increase the likelihood of damaging earthquakes in the eastern portion of North America.

  14. Mesoscale cyclogenesis over the western north Pacific Ocean during TPARC

    Directory of Open Access Journals (Sweden)

    Christopher A. Davis

    2013-01-01

    Full Text Available Three cases of mesoscale marine cyclogenesis over the subtropics of the Western Pacific Ocean are investigated. Each case occurred during the THORPEX Pacific Asia Regional Campaign and Tropical Cyclone Structure (TCS-08 field phases in 2008. Each cyclone developed from remnants of disturbances that earlier showed potential for tropical cyclogenesis within the tropics. Two of the cyclones produced gale-force surface winds, and one, designated as a tropical cyclone, resulted in a significant coastal storm over eastern Japan. Development was initiated by a burst of organized mesoscale convection that consolidated and intensified the surface cyclonic circulation over a period of 12–24 h. Upper-tropospheric potential vorticity anomalies modulated the vertical wind shear that, in turn, influenced the periods of cyclone intensification and weakening. Weak baroclinicity associated with vertical shear was also deemed important in organizing mesoscale ascent and the convection outbreaks. The remnant tropical disturbances contributed exceptional water vapour content to higher latitudes that led to strong diabatic heating, and the tropical remnants contributed vorticity that was the seed of the development in the subtropics. Predictability of these events more than three days in advance appears to be minimal.

  15. North and equatorial Pacific Ocean circulation in the CORE-II hindcast simulations

    Science.gov (United States)

    Tseng, Yu-heng; Lin, Hongyang; Chen, Han-ching; Thompson, Keith; Bentsen, Mats; Böning, Claus W.; Bozec, Alexandra; Cassou, Christophe; Chassignet, Eric; Chow, Chun Hoe; Danabasoglu, Gokhan; Danilov, Sergey; Farneti, Riccardo; Fogli, Pier Giuseppe; Fujii, Yosuke; Griffies, Stephen M.; Ilicak, Mehmet; Jung, Thomas; Masina, Simona; Navarra, Antonio; Patara, Lavinia; Samuels, Bonita L.; Scheinert, Markus; Sidorenko, Dmitry; Sui, Chung-Hsiung; Tsujino, Hiroyuki; Valcke, Sophie; Voldoire, Aurore; Wang, Qiang; Yeager, Steve G.

    2016-08-01

    We evaluate the mean circulation patterns, water mass distributions, and tropical dynamics of the North and Equatorial Pacific Ocean based on a suite of global ocean-sea ice simulations driven by the CORE-II atmospheric forcing from 1963-2007. The first three moments (mean, standard deviation and skewness) of sea surface height and surface temperature variability are assessed against observations. Large discrepancies are found in the variance and skewness of sea surface height and in the skewness of sea surface temperature. Comparing with the observation, most models underestimate the Kuroshio transport in the Asian Marginal seas due to the missing influence of the unresolved western boundary current and meso-scale eddies. In terms of the Mixed Layer Depths (MLDs) in the North Pacific, the two observed maxima associated with Subtropical Mode Water and Central Mode Water formation coalesce into a large pool of deep MLDs in all participating models, but another local maximum associated with the formation of Eastern Subtropical Mode Water can be found in all models with different magnitudes. The main model bias of deep MLDs results from excessive Subtropical Mode Water formation due to inaccurate representation of the Kuroshio separation and of the associated excessively warm and salty Kuroshio water. Further water mass analysis shows that the North Pacific Intermediate Water can penetrate southward in most models, but its distribution greatly varies among models depending not only on grid resolution and vertical coordinate but also on the model dynamics. All simulations show overall similar large scale tropical current system, but with differences in the structures of the Equatorial Undercurrent. We also confirm the key role of the meridional gradient of the wind stress curl in driving the equatorial transport, leading to a generally weak North Equatorial Counter Current in all models due to inaccurate CORE-II equatorial wind fields. Most models show a larger

  16. Cenozoic evolution of the eastern Danish North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Huuse, M.; Lykke-Andersen, H.; Michelsen, O.

    2003-12-01

    This paper provides a review of recent high-resolution and conventional seismic investigations in the eastern Danish North Sea and destribes their implications for the development of the eastern North Sea Basin. The results tomprise detailed timestructure maps of four major unconformities in the eastern Danish North Sea: the Top Chalk surface (mid-Paleogene), near top Oligocene, the mid-Miocene unconformity, and base Quatemary. The maps show that the eastem Danish North Sea has been affected by fauldng and salt diapirism throughout the Cenozoic. Carbonate mounds, erosional valleys and pockmark- or karstlike struttures were identitied at the top of the Upper Cretaceous-Danian Chalk Group. Strike-parallel erosional features and depositional geometries observed at near top Oligocene and at the mid-Miocene unconformity indicate that these major sequence boundarics tan be attributed to large-scale lateral changes in sediment supply directions. Increases in sediment flux to the southeastern North Sea at the Eocene/Oligocene transition and in the post-Middle Miocene appear to correlate with similar events world wide and with long term {delta} {sup 18} O increases, indicating forting by global factors, i.e. eustasy and climate. Stratal geometries observed on the seismic data indicate that the socalled `Neogene uplift' of the Bastern Danish North Sea may have been hundreds of metres less than previously suggested. lt is argued that late Cenozoic uplift of the basin margin and of mountain peaks in southern Norway may have been caused entirely by isostatic uplift of the trust in response to accelerated late Cenozoic denudation and dissection of topography created in the Paleogene. The late Cenozoic periods of accelerated denudation and incision rates were most likely driven by climatic deterioration and long term eustatic lowering rather than active late Cenozoic tectonics, the cause of which is conjectural. A series of shallow thrust struttures and an associated system

  17. Mortalities of eastern and pacific oyster larvae caused by the pathogens Vibrio coralliilyticus and Vibrio tubiashii

    Science.gov (United States)

    Vibrio tubiashii is reported to be a bacterial pathogen of larval Eastern oysters (Crassostrea virginica) and Pacific oysters (Crassostrea gigas) and has been associated with major hatchery crashes, causing shortages in seed oysters for commercial shellfish producers. Another bacterium, Vibrio cora...

  18. Particulate silica and Si recycling in the surface waters of the Eastern Equatorial Pacific

    DEFF Research Database (Denmark)

    Adjou, Mohamed; Tréguer, Paul; Dumousseaud, Cynthia

    2011-01-01

    The distributions of biogenic and lithogenic silica concentrations and net silica production rates in the upper 120 m of the Eastern Equatorial Pacific (EEP) were examined in December 2004, on two transects situated at 110°W (4°N to 3°S) and along the equator (110°W to 140°W). Lithogenic silica (...

  19. Revision of Hydroides Gunnerus, 1768 (Polychaeta: Serpulidae) from the Eastern Pacific region and Hawaii

    NARCIS (Netherlands)

    Bastida-Zavala, J. Rolando; Hove, ten Harry A.

    2003-01-01

    A taxonomic revision of the Hydroides species (Polychaeta: Serpulidae) from the Eastern Pacific Ocean is presented. Twentyone taxa are described, of which two are widespread (H. diramphus Mörch, 1863 and H. elegans (Haswell, 1883)) and four are Amphiamerican (H. alatalateralis (Jones, 1962), H.

  20. Eastern equatorial Pacific Ocean T-S variations with El Nino

    Science.gov (United States)

    Wang, O.; Fukumori, I.; Lee, T.; Johnson, G. C.

    2004-01-01

    Temperature-Salinity (T-S) relationship variability in the pycnocline of the eastern equatorial Pacific Ocean (NINO3 region, 5 degrees S ??degrees N, 150 degrees W ?? degrees W) over the last two decades is investigated using observational data and model simulation.

  1. El Niño and coral larval dispersal across the eastern Pacific marine barrier

    Science.gov (United States)

    Wood, S.; Baums, I. B.; Paris, C. B.; Ridgwell, A.; Kessler, W. S.; Hendy, E. J.

    2016-08-01

    More than 5,000 km separates the frequently disturbed coral reefs of the Eastern Tropical Pacific (ETP) from western sources of population replenishment. It has been hypothesized that El Niño events facilitate eastward dispersal across this East Pacific Barrier (EPB). Here we present a biophysical coral larval dispersal model driven by 14.5 years of high-resolution surface ocean current data including the extreme 1997-1998 El Niño. We find no eastward cross-EPB connections over this period, which implies that ETP coral populations decimated by the 1998 bleaching event can only have recovered from eastern Pacific sources, in congruence with genetic data. Instead, rare connections between eastern and central Pacific reefs are simulated in a westward direction. Significant complexity and variability in the surface flows transporting larvae mean that generalized upper-ocean circulation patterns are poor descriptors of inter-regional connectivity, complicating the assessment of how climate change will impact coral gene flow Pacific wide.

  2. 50 CFR 226.215 - Critical habitat for the North Pacific Right Whale (Eubalaena japonica).

    Science.gov (United States)

    2010-10-01

    ... Right Whale (Eubalaena japonica). 226.215 Section 226.215 Wildlife and Fisheries NATIONAL MARINE... DESIGNATED CRITICAL HABITAT § 226.215 Critical habitat for the North Pacific Right Whale (Eubalaena japonica). (a) Primary Constituent Elements. The primary constituent elements of the North Pacific right...

  3. Genetic isolation between the Western and Eastern Pacific populations of pronghorn spiny lobster Panulirus penicillatus.

    Directory of Open Access Journals (Sweden)

    Seinen Chow

    Full Text Available The pronghorn spiny lobster, Panulirus penicillatus, is a circumtropical species which has the widest global distribution among all the species of spiny lobster, ranging throughout the entire Indo-Pacific region. Partial nucleotide sequences of mitochondrial DNA COI (1,142-1,207 bp and 16S rDNA (535-546 bp regions were determined for adult and phyllosoma larval samples collected from the Eastern Pacific (EP(Galápagos Islands and its adjacent water, Central Pacific (CP(Hawaii and Tuamotu and the Western Pacific (WP(Japan, Indonesia, Fiji, New Caledonia and Australia. Phylogenetic analyses revealed two distinct large clades corresponding to the geographic origin of samples (EP and CP+WP. No haplotype was shared between the two regional samples, and average nucleotide sequence divergence (Kimura's two parameter distance between EP and CP+WP samples was 3.8±0.5% for COI and 1.0±0.4% for 16S rDNA, both of which were much larger than those within samples. The present results indicate that the Pacific population of the pronghorn spiny lobster is subdivided into two distinct populations (Eastern Pacific and Central to Western Pacific, with no gene flow between them. Although the pronghorn spiny lobster have long-lived teleplanic larvae, the vast expanse of Pacific Ocean with no islands and no shallow substrate which is known as the East Pacific Barrier appears to have isolated these two populations for a long time (c.a. 1MY.

  4. Trail Trees: Living Artifacts (Vivifacts of Eastern North America

    Directory of Open Access Journals (Sweden)

    Nicholas C. Kawa

    2015-09-01

    Full Text Available Living trees historically modified by human populations, oftentimes referred to as “culturally modified trees” (CMTs, are found throughout the North American landscape. In eastern North America specifically, indigenous populations bent thousands of trees to mark trails, and some of these still exist in the region today. In this article, we present a synthesis of current knowledge on trail trees, including their speculated functions, formation, and selection. We also examine the theoretical implications of these living artifacts (or vivifacts and how they may open new avenues for investigation by archaeologists, environmental historians, and ethnobiologists. To conclude, we make a call for expanded public recognition and documentation of trail trees, discussing the need for their incorporation into forest and park management plans.

  5. Cross equator transport of 137Cs from North Pacific Ocean to South Pacific Ocean ( BEAGLE2003 cruises)

    Science.gov (United States)

    Aoyama, M.; Fukasawa, M.; Hirose, K.; Hamajima, Y.; Kawano, T.; Povinec, P. P.; Sanchez-Cabeza, J. A.

    2011-04-01

    The anthropogenic radionuclides such as 137Cs, 90Sr, 99Tc, 129I and some transuranics are important tracers of transport and biogeochemical processes in the ocean. 137Cs, with a half-life of 30 years, a major fission product present in a dissolved form in seawater, is a good tracer of oceanic circulation at a time scale of several decades. At WOCE P6 line along 30°S during the BEAGLE cruise in 2003, surface seawater (around 80 L) was collected a few meters below the ocean surface by a pumping system. Water column samples (from 5 to 20 L) were collected using a Rosette multisampling system and Niskin bottles. 137Cs was separated from seawater samples using ammonium phosphomolybdate (AMP) and analysed for 137Cs in low-level HPGe gamma-ray spectrometers. Results allowed to draw a detailed picture of the distribution of 137Cs in the South Pacific Ocean along P6 line. A 137Cs depth section was depicted from about 160 samples. 137Cs concentrations in the subsurface layers ranged from 0.07 ± 0.04 Bq m -3 to 1.85 ± 0.145 Bq m -3, high in the Tasman Sea and very low in the eastern region where upwelling occurs. Water column inventories of 137Cs from surface to 1000 dbar depth ranged from 270 ± 104 to 1048 ± 127 Bq m -2. It was concluded that the source of higher 137Cs concentration and inventories in the Tasman Sea was 137Cs deposited in the mid latitude of the North Pacific Ocean and transported across the equator during four decades.

  6. Mortalities of Eastern and Pacific oyster Larvae caused by the pathogens Vibrio coralliilyticus and Vibrio tubiashii.

    Science.gov (United States)

    Richards, Gary P; Watson, Michael A; Needleman, David S; Church, Karlee M; Häse, Claudia C

    2015-01-01

    Vibrio tubiashii is reported to be a bacterial pathogen of larval Eastern oysters (Crassostrea virginica) and Pacific oysters (Crassostrea gigas) and has been associated with major hatchery crashes, causing shortages in seed oysters for commercial shellfish producers. Another bacterium, Vibrio coralliilyticus, a well-known coral pathogen, has recently been shown to elicit mortality in fish and shellfish. Several strains of V. coralliilyticus, such as ATCC 19105 and Pacific isolates RE22 and RE98, were misidentified as V. tubiashii until recently. We compared the mortalities caused by two V. tubiashii and four V. coralliilyticus strains in Eastern and Pacific oyster larvae. The 50% lethal dose (LD50) of V. coralliilyticus in Eastern oysters (defined here as the dose required to kill 50% of the population in 6 days) ranged from 1.1 × 10(4) to 3.0 × 10(4) CFU/ml seawater; strains RE98 and RE22 were the most virulent. This study shows that V. coralliilyticus causes mortality in Eastern oyster larvae. Results for Pacific oysters were similar, with LD50s between 1.2 × 10(4) and 4.0 × 10(4) CFU/ml. Vibrio tubiashii ATCC 19106 and ATCC 19109 were highly infectious toward Eastern oyster larvae but were essentially nonpathogenic toward healthy Pacific oyster larvae at dosages of ≥1.1 × 10(4) CFU/ml. These data, coupled with the fact that several isolates originally thought to be V. tubiashii are actually V. coralliilyticus, suggest that V. coralliilyticus has been a more significant pathogen for larval bivalve shellfish than V. tubiashii, particularly on the U.S. West Coast, contributing to substantial hatchery-associated morbidity and mortality in recent years.

  7. Vertical structure variability and equatorial waves during central Pacific and eastern Pacific El Ninos in a coupled general circulation model

    Energy Technology Data Exchange (ETDEWEB)

    Dewitte, B.; Thual, S. [LEGOS/IRD, Toulouse (France); Choi, J.; An, S.I. [Yonsei University, Seoul (Korea, Republic of)

    2012-06-15

    Recent studies report that two types of El Nino events have been observed. One is the cold tongue El Nino or Eastern Pacific El Nino (EP El Nino), which is characterized by relatively large sea surface temperature (SST) anomalies in the eastern Pacific, and the other is the warm pool El Nino (a.k.a. 'Central Pacific El Nino' (CP El Nino) or 'El Nino Modoki'), in which SST anomalies are confined to the central Pacific. Here the vertical structure variability of the periods during EP and CP is investigated based on the GFDL{sub C}M2.1 model in order to explain the difference in equatorial wave dynamics and associated negative feedback mechanisms. It is shown that the mean stratification in the vicinity of the thermocline of the central Pacific is reduced during CP El Nino, which favours the contribution of the gravest baroclinic mode relatively to the higher-order slower baroclinic mode. Energetic Kelvin and first-meridional Rossby wave are evidenced during the CP El Nino with distinctive amplitude and propagating characteristics according to their vertical structure (mostly first and second baroclinic modes). In particular, the first baroclinic mode during CP El Nino is associated to the ocean basin mode and participates to the recharge process during the whole El Nino cycle, whereas the second baroclinic mode is mostly driving the discharge process through the delayed oscillator mechanism. This may explain that the phase transition from warm to neutral/cold conditions during the CP El Nino is delayed and/or disrupted compared to the EP El Nino. Our results have implications for the interpretation of the variability during periods of high CP El Nino occurrence like the last decade. (orig.)

  8. Drought reconstruction in eastern Hulun Buir steppe, China and its linkages to the sea surface temperatures in the Pacific Ocean

    Science.gov (United States)

    Liu, Na; Liu, Yu; Bao, Guang; Bao, Ming; Wang, Yanchao; Zhang, Lizhi; Ge, Yuxiang; Bao, Wurigen; Tian, Heng

    2016-01-01

    A tree-ring width chronology covering the period 1780-2013 AD was developed from Pinus sylvestris var. mongolica for the eastern Hulun Buir steppe, a region located on the edge of the eastern Mongolian Plateau, China. Climate-growth response analysis revealed drought stress to be the primary limiting factor for tree growth. Therefore, the mean February-July standardized precipitation evapotranspiration index (SPEI) was reconstructed over the period 1819-2013, where the reconstruction could account for 32.8% of the variance in the instrumental record over the calibration period 1953-2011. Comparison with other tree-ring-based moisture sequences from nearby areas confirmed a high degree of confidence in our reconstruction. Severe drought intervals since the late 1970s in our study area consisted with the weakening East Asian summer monsoon, which modulating regional moisture conditions in semi-arid zone over northern China. Drought variations in the study area significantly correlated with sea surface temperatures (SSTs) in North Pacific Ocean, suggesting a possible connection of regional hydroclimatic variations to the Pacific Decadal Oscillation (PDO). The potential influence associated with El Niño-Southern Oscillation (ENSO) was primarily analyzed.

  9. Epipelagic copepod distributions in the eastern equatorial Pacific during the weak La Niña event of 2001

    Directory of Open Access Journals (Sweden)

    Pritha Tutasi

    2011-07-01

    Full Text Available We determined the distribution and abundance of pelagic copepods in the eastern equatorial Pacific between the coast of Ecuador and the Galapagos Islands under oceanographic conditions associated with the weak La Niña event of 2001. In September-October 2001, negative anomalies of sea surface temperature from this event still remained in the eastern equatorial Pacific, mainly between Ecuador and the Galapagos Islands. The event allowed the incursion of the Humboldt Current farther north and of the Equatorial Undercurrent into the study area, favouring a strong Equatorial Front and upwelling processes. There was evidence of mesoscale eddies in the study area and of the presence of the South Equatorial Current going westward at about 1°N. We identified 107 copepod species and analyzed the distribution of the 10 most abundant ones: Oncaea venusta, Subeucalanus pileatus, S. crassus, S. subtenuis, Paraeucalanus attenuatus, Pleuromamma borealis, Scolecithrix danae, Clausocalanus farrani, Temora discaudata and Calanus chilensis. Copepod distribution and abundance exhibited marked latitudinal differences related to the oceanographic conditions; abundance was highest to the southeast of the Galapagos Islands. Oncaea venusta, Pleuromamma borealis, Calanus chilensis, and Subeucalanus subtenuis were the species that best defined the Equatorial Front and the upwelling process.

  10. Occult Dirofilariosis in Dogs of North Eastern Region in India

    Directory of Open Access Journals (Sweden)

    Sonjoy Kumar-Borthakur

    2015-10-01

    Full Text Available Background: The North Eastern Region in India is endemic for canine heartworm disease but in clinics accurate diagnosis is some times difficult. The aim of the present study was to determine the prevalence of occult infections for heartworm disease in canine in two geographical regions of North Eastern India.Methods: A total of 782 numbers of three categories of dogs namely, working dogs of military and paramilitary forces, pet dogs and stray dogs were screened for the presence of heartworm infection from August 2011 to July, 2012 in Guwahati (Assam and Aizawl (Mizoram. Conventional, immunological and molecular techniques were followed for this epidemiological study. The criteria to determine the occult heartworm cases were based on the dif­ferences between heartworm positive cases in PCR test and antigen ELISA test.Results: The findings revealed an overall 22.69 percent occult case. The working dogs had highest prevalence (60% followed by pet (29.16% and stray dogs (17.75%.Conclusion: The highest percentage of occult heartworm infection was present in working dogs maintained under military or paramilitary forces. 

  11. REVIEW: MONASTIC AND LAY TRADITIONS IN NORTH-EASTERN TIBET

    Directory of Open Access Journals (Sweden)

    Benno Weiner

    2015-03-01

    Full Text Available Review of: Yangdon Dhondup, Ulrich Pagel, and Geoffrey Samuel (eds. 2013. Monastic and Lay Traditions of North-Eastern Tibet. Leiden and Boston: Brill. Monastic and Lay Traditions in North-Eastern Tibet, edited by Yangdon Dhondup, Ulrich Pagel, and Geoffrey Samuel, is the product of a 2011 workshop convened at St. Michael's College, Llandaff, Cardiff. Although the conference's focus was the tantric practitioner community of the Reb kong region (Ch. Tongren, the resultant volume expands the scope of inquiry to include surrounding areas as well as monastic communities. The editors have organized the volume's nine chapters into three sections, the first on the Dge lugs pa monastic establishment, the second on Rnying ma pa and Bon tantric communities, and finally 'Ritual and Performance in Contemporary Reb kong'. While the chapters are all informative and scholarly, providing new, important empirical detail on an underresearched subject, several tend toward the descriptive. The most successful contributions, however, present their findings within larger analytical and contextual frameworks, giving their chapters explanatory weight beyond the more narrow confines of their studies.

  12. The plastic-associated microorganisms of the North Pacific Gyre.

    Science.gov (United States)

    Carson, Henry S; Nerheim, Magnus S; Carroll, Katherine A; Eriksen, Marcus

    2013-10-15

    Microorganisms likely mediate processes affecting the fate and impacts of marine plastic pollution, including degradation, chemical adsorption, and colonization or ingestion by macroorganisms. We investigated the relationship between plastic-associated microorganism communities and factors such as location, temperature, salinity, plankton abundance, plastic concentration, item size, surface roughness, and polymer type. Small plastic items from the surface of the North Pacific Gyre in 2011 were examined using scanning electron microscopy. Bacillus bacteria (mean 1664 ± 247 individuals mm(-2)) and pennate diatoms (1097 ± 154 mm(-2)) were most abundant, with coccoid bacteria, centric diatoms, dinoflagellates, coccolithophores, and radiolarians present. Bacterial abundance was patchy, but increased on foamed polystyrene. Diatom abundance increased on items with rough surfaces and at sites with high plastic concentrations. Morphotype richness increased slightly on larger fragments, and a biogeographic transition occurred between pennate diatom groups. Better characterizing this community will aid in understanding how it interacts with plastic pollution.

  13. Chemical oceanography. Increasing anthropogenic nitrogen in the North Pacific Ocean.

    Science.gov (United States)

    Kim, Il-Nam; Lee, Kitack; Gruber, Nicolas; Karl, David M; Bullister, John L; Yang, Simon; Kim, Tae-Wook

    2014-11-28

    The recent increase in anthropogenic emissions of reactive nitrogen from northeastern Asia and the subsequent enhanced deposition over the extensive regions of the North Pacific Ocean (NPO) have led to a detectable increase in the nitrate (N) concentration of the upper ocean. The rate of increase of excess N relative to phosphate (P) was found to be highest (~0.24 micromoles per kilogram per year) in the vicinity of the Asian source continent, with rates decreasing eastward across the NPO, consistent with the magnitude and distribution of atmospheric nitrogen deposition. This anthropogenically driven increase in the N content of the upper NPO may enhance primary production in this N-limited region, potentially leading to a long-term change of the NPO from being N-limited to P-limited. Copyright © 2014, American Association for the Advancement of Science.

  14. Variability of the North Pacific Current and its bifurcation

    Science.gov (United States)

    Cummins, Patrick F.; Freeland, Howard J.

    2007-10-01

    The North Pacific Current (NPC) bifurcates approaching the west coast of North America into a subpolar branch that forms the Alaska Current, and a subtropical branch that includes the California Current. The variability of this current system is discussed using numerical results from a wind-driven, reduced-gravity model. Indices of the strength of the subpolar and subtropical components of the NPC are examined based on output from multi-decadal simulations with the numerical model. This shows periods of both correlated and anti-correlated variability of the subpolar and subtropical gyres. A decomposition of the gyre transport time series indicates that the dominant mode of variability is a “breathing” mode in which the subpolar and subtropical gyres co-vary in response to fluctuations in the strength of the NPC. This finding is consistent with an analysis of dynamic height data of limited duration from the array of Argo drifting floats. The variability of the NPC is also examined using sea surface height (SSH) data from satellite altimetry over the period 1993-2005. The leading mode of SSH over the northeast Pacific dominates the variability of the NPC and is shown to be associated with in-phase variations in the transport of the subtropical and subpolar gyres. A strong correlation is found between time-dependent fluctuations in SSH across the NPC and variations in the strength of the transport of the NPC in the model. This agreement provides evidence for variability of the NPC occuring in direct response to large-scale atmospheric forcing.

  15. Interannual Variation of Multiple Tropical Cyclone Events in the Western North Pacific

    Institute of Scientific and Technical Information of China (English)

    GAO Jianyun; Tim LI

    2012-01-01

    The interannual variability of occurrence of multiple tropical cyclone (MTC) events during June-October in the western North Pacific (WNP) was examined for the period 1979-2006.The number of the MTC events ranged from 2 to 9 per year,exhibiting a remarkable year-to-year variation.Seven active and seven inactive MTC years were identified.Compared to the inactive years,tropical cyclone genesis locations extended farther to the east and in the meridional direction during the active MTC years.A composite analysis shows that inactive MTC years were often associated with the El Ni(n)o decaying phase,as warm SST anomalies in the equatorial eastern-central Pacific in the preceding winter transitioned into cold sea surface temperature (SST) anomalies in the concurrent summer.Associated with the SST evolution were suppressed low-level cyclonic vorticity and weakened convection in the WNP monsoon region.In addition to the mean flow difference,significant differences between active and inactive MTC years were also found in the strength of the atmospheric intraseasonal oscillation (ISO).Compared with inactive MTC years,ISO activity was much stronger along the equator and in the WNP region during active MTC years.Both westward- and northward-propagating ISO spectrums strengthened during active MTC years compared to inactive years.The combined mean state and ISO activity changes may set up a favorable environment for the generation of MTC events.

  16. Connection between the Eastern Subtropical Mode Water in the South Pacific Ocean and the ENSO cycle

    Science.gov (United States)

    Li, Z.

    2012-12-01

    Water subducted in the subtropics is intimately linked to the circulation in the Tropics through the interior mass communication and/or the western boundary, and could potentially affect climate variability on interannual and decadal time scales (Gu and Philander, 1997). The interior mass communication rate between the subtropical and equatorial ocean can be quantified in different ways. For example, Huang and Wang (2001) proposed a method of using the Sverdrup function to quantify the communication rate. Their method is used here to compute the meridional transport function below the Ekman layer in order to investigate the direct communication from the eastern STMW to the equatorial Pacific, and study the connection between the eastern STMW and the ENSO cycle. The western subtropical mode water, however, is less likely to directly participate in the subtropical-tropical exchange because they are mainly formed and confined to the recirculation region of the western subtropical gyre (Ladd and Thompson, 2000). The variability of the Subtropical Mode Water (STMW) formation in the South Pacific Ocean from 1980 to 2004 is investigated in this study, using a high-resolution numerical model and a 3D Lagrangian trajectory model. Variations of subduction rate in the mode waters are closely linked to the El Niño-Southern Oscillation (ENSO) cycle. The eastern STMW could potentially affect the ENSO cycle through the interior communication window that was identified from the virtual streamfunction. Its location and width closely related to the ENSO cycle. The deep westward penetration of the western edge of the window at the equatorial Pacific is evident during the 1998 La Niña event.; Zonal location of the interior communication window for eastern STMW, when the subducted water parcels reach the equatorial Pacific at 10oS. Solid gray (black) line represents the western (eastern) edge of the window.

  17. Evaluation of the eastern equatorial Pacific SST seasonal cycle in CMIP5 models

    Directory of Open Access Journals (Sweden)

    Z. Song

    2014-04-01

    Full Text Available The annual cycle of sea surface temperature (SST in the eastern equatorial Pacific (EEP with the largest amplitude in the tropical oceans is poorly represented in the coupled general circulation models (CGCMs of the Coupled Model Intercomparison Project phase 3 (CMIP3. In this study, 18 models from CMIP5 projects are evaluated in simulating the annual cycle in the EEP. Fourteen models are able to simulate the annual cycle, and four still show erroneous information in the simulation, which suggests that the performances of CGCMs have been improved. The results of multi-model ensemble (MME mean show that CMIP5 CGCMs can capture the annual cycle signal in the EEP with correlation coefficients up to 0.9. For amplitude simulations, EEP region 1 (EP1 near the eastern coast shows weaker results than observations due to the large warm SST bias from the southeastern tropical Pacific in the boreal autumn. In EEP region 2 (EP2 near the central equatorial Pacific, the simulated amplitudes are nearly the same as the observations because of the presence of a quasi-constant cold bias associated with poor cold tongue climatology simulation in the CGCMs. To improve CGCMs in the simulation of a realistic SST seasonal cycle, local and remote climatology SST biases that exist in both CMIP3 and CMIP5 CGCMs must be resolved at least for the simulation in the central equatorial Pacific and the southeastern tropical Pacific.

  18. Modes of hurricane activity variability in the eastern Pacific: Implications for the 2016 season

    Science.gov (United States)

    Boucharel, Julien; Jin, Fei-Fei; England, Matthew H.; Lin, I. I.

    2016-11-01

    A gridded product of accumulated cyclone energy (ACE) in the eastern Pacific is constructed to assess the dominant mode of tropical cyclone (TC) activity variability. Results of an empirical orthogonal function decomposition and regression analysis of environmental variables indicate that the two dominant modes of ACE variability (40% of the total variance) are related to different flavors of the El Niño-Southern Oscillation (ENSO). The first mode, more active during the later part of the hurricane season (September-November), is linked to the eastern Pacific El Niño through the delayed oceanic control associated with the recharge-discharge mechanism. The second mode, dominant in the early months of the hurricane season, is related to the central Pacific El Niño mode and the associated changes in atmospheric variability. A multilinear regression forecast model of the dominant principal components of ACE variability is then constructed. The wintertime subsurface state of the eastern equatorial Pacific (characterizing ENSO heat discharge), the east-west tilt of the thermocline (describing ENSO phase transition), the anomalous ocean surface conditions in the TC region in spring (portraying atmospheric changes induced by persistence of local surface anomalies), and the intraseasonal atmospheric variability in the western Pacific are found to be good predictors of TC activity. Results complement NOAA's official forecast by providing additional spatial and temporal information. They indicate a more active 2016 season ( 2 times the ACE mean) with a spatial expansion into the central Pacific associated with the heat discharge from the 2015/2016 El Niño.

  19. Evolution of the mantle beneath the eastern North China Craton during the Cenozoic: Linking geochemical and geophysical observations

    Science.gov (United States)

    Li, Hong-Yan; Xu, Yi-Gang; Ryan, Jeffrey G.; Whattam, Scott A.

    2017-01-01

    Recent discoveries related to the geochemistry of Cenozoic basalts and the geophysics of the deep mantle beneath eastern Eurasia make it possible to place constraints on the relationship between the seismic tomography of subcontinental mantle domains and their geochemical heterogeneities. Basalts with ocean island basalt-like trace elements erupted during (56-23 Ma) and after (≤23 Ma) rifting of the eastern North China Craton (NCC) show evidence for the mixing of an isotopically depleted source and an EMI (Enriched mantle type I) pyroxenitic mantle. NCC rifting-stage basalts exhibit anomalously low MgO and Fe2O3T and high SiO2 and Al2O3, as well as low Dy/Yb and Y/Yb and high ɛHf at a given ɛNd, as compared to the postrifting basalts. Temporal compositional variations and their association with basin subsidence indicate that heterogeneity in the eastern NCC asthenospheric mantle is the primary driver for intraplate magmatism in this region. The specific magmatic sources shifted in terms of depth, related to lithospheric thinning and thickening in the eastern NCC. The NCC EMI mantle domain most likely developed due to ancient events, is persistent through time, and is not related to dehydration of the stagnant Pacific slab in the mantle transition zone. Based on the chemical signatures of postrifting basalts, contributions from the Pacific slab are likely to be carbonatite rich. Mantle metasomatism by carbonatite melts from the Pacific slab and the interaction of these melts at shallower depths with EMI pyroxenitic mantle domains to trigger melting are contributors to the observed low P wave velocity zone beneath eastern Eurasia.

  20. Liquefaction hazard potential in north eastern united arab emirates

    Science.gov (United States)

    Al-Homoud, A.

    2003-04-01

    The United Arab Emirates is adjacent to the Iranian plateau characterized by very high density of active and recent faults. The Iranian plateau is one of the seismically active areas of the world and frequently suffers destructive and catastrophic earthquakes that cause heavy loss of human life and widespread damage. Therefore seismic risk in the North Eastern UAE (Sharjah and Dubai) is due to the neighboring very active Iranian seismotectonic province. As almost all foundation soils in the UAE are cohesionless material, which is clearly identified as recent fill deposits in major industrial and residential areas, and given the rapid on-shore infrastructure developments in the North Eastern UAE, and due to the lack of geo-hazards maps, it is considered vital to develop liquefaction hazard maps for these areas. The earthquake risk was brought to the attention of the public and the government upon the recent March 11, 2002 earthquake of magnitude 5.1 on Richter Scale that struck the northern emirates and caused slight damages. Initial seismic hazard assessment studies showed that Design Horizontal Peak Ground Accelerations (PGA) in Sharjah and Dubai with 90% probabilities of non-exceedence in 50 years is around 200 cm/sec^2. This study is concerned with the development of liquefaction hazard maps in North Eastern Emirates UAE Cities of Sharjah and Dubai. Liquefaction hazard potential for various soil deposits in these cities is evaluated for different Peak Ground Acceleation Values. Data from thorough geotechnical studies were evaluated. This include boreholes drilling (with SPT tests) and shear strength for representative sand samples taken from several boreholes and at different depths. Liquefaction hazard potential is evaluated at representative sites in the city of Dubai and Sharjah using the state of the art liquefaction potential evaluation methods (e.g. Seed's cyclic stress ratio approach). Results indicate clearly that the coastal areas have a high potential

  1. Gymnothorax phalarus, a new eastern Pacific moray eel (Pisces: Muraenidae

    Directory of Open Access Journals (Sweden)

    William A. Bussing

    1998-06-01

    Full Text Available Gymnothorax phalarus is described from 23 individuals taken in trawl and dredge collections made on the Pacific coast of Costa Rica. The new species is nearly always syntopic with a similar species, Gymnothorax equatorialis. The new moray is distinguished by its white-spotted pattern, uniserial, slightly serrated teeth in adults, four infraorbital pores and mean vertebral formula of 6-58-140. Of the total of 21 valid species of morays recorded from the Pacific coast of Costa Rica, only the new species and G. equatorialis form part of the trawl fishery as the remainder are almost entirely restricted to nearshore rocky habitats. The known range of G. phalarus is from Baja California to Peru.Gymnothorax phalarus se describe con base en 23 individuos de colecciones hechas por redes de arrastre y dragas en la costa Pacífica de Costa Rica. La especie nueva es casi siempre sintópica con la especie similar, Gymnothorax equatorialis. La nueva morena se distingue por su patrón de puntos blancos, dientes ligeramente aserrados y uniseriales en adultos, cuatro poros infraorbitales y MVF (Fórmula de Vértebras de 6-58-140. México a Perú.

  2. Trans-Pacific and trans-Arctic pathways of the intertidal macroalga Fucus distichus L. reveal multiple glacial refugia and colonizations from the North Pacific to the North Atlantic

    NARCIS (Netherlands)

    Coyer, James A.; Hoarau, Galice; Van Schaik, Jaap; Luijckx, Pepijn; Olsen, Jeanine L.

    2011-01-01

    Aim We examined the phylogeography of the cold-temperate macroalgal species Fucus distichus L., a key foundation species in rocky intertidal shores and the only Fucus species to occur naturally in both the North Pacific and the North Atlantic. Location North Pacific and North Atlantic oceans (42 deg

  3. Influence of the Western Pacific teleconnection pattern on Western North Pacific tropical cyclone activity

    Science.gov (United States)

    Choi, Ki-Seon; Moon, Il-Ju

    2012-09-01

    This study analyzes the characteristics of Western North Pacific (WNP) tropical cyclone (TC) activity and large-scale environments according to the Western Pacific (WP) teleconnection pattern in summer. In the positive WP phase, an anomalous cyclone and an anomalous anticyclone develop in the low and middle latitudes of the East Asia area, respectively. As a result, southeasterlies are reinforced in the northeast area of East Asia (including Korea and Japan), which facilitates the movement of TC to this area, whereas northwesterlies are reinforced in the southwest area of East Asia (including southern China and the Indochina Peninsula) which blocks the movement of TC to that area. Due to the spatial distribution of this reinforced pressure system, TCs that develop during the positive WP phase move and turn more to the northeast of the WNP than TCs which develop during the negative WP phase. The characteristics of this TC activity during the positive WP phase are associated with the upper tropospheric jet being located farther to the northeast. TCs during the negative WP phase mainly move to the west from the Philippines toward southern China and the Indochina Peninsula. Due to the terrain effect caused by the passage of TCs in mainland China, the intensity of TCs during the negative WP phase is weaker than those during the positive WP phase.

  4. Evaluating regional differences in macroinvertebrate communities from forested depressional wetlands across eastern and central North America

    Science.gov (United States)

    Darold P. Batzer; Susan E. Dietz-Brantley; Barbara E. Taylor; Adrienne E. DeBiase

    2005-01-01

    Forested depressional wetlands are an important seasonal wetland type across eastern and central North America. Macroinvertebrates are crucial ecosystem components of most forested depressional wetlands, but community compositions can vary widely across the region. We evaluated variation in macroinvertebrate faunas across eastern and central North America using 5...

  5. Fluorescence signatures of an iron-enriched phytoplankton community in the eastern equatorial Pacific Ocean

    Science.gov (United States)

    Hoge, Frank E.; Wayne Wright, C.; Swift, Robert N.; Yungel, James K.; Berry, Richard E.; Mitchell, Richard

    Laser-induced fluorescence profiles of chlorophyll and phycoerythrin pigments and chromophoric dissolved organic matter (CDOM) fluorescence acquired over an iron-enriched phytoplankton patch are compared to profiles made over adjacent, naturally occurring phytoplankton patches. A total of four airborne missions were flown during an 8 day period following the release of the iron-rich fertilizer. Analyses of the airborne laser-induced fluorescence profiles from the upper-ocean layer reveal: (1) Ship-dispersed iron enhances localized phytoplankton production in high-nutrient/low-chlorophyll regions such as found in the eastern equatorial Pacific Ocean. (2) The chlorophyll concentration within the iron-enriched phytoplankton patch exceeded levels of chlorophyll found in naturally occurring phytoplankton patches located outside the enriched region. (3) An increase in phycoerythrin fluorescence was observed within the enriched region in correspondence with the elevated chlorophyll fluorescence. However, the phycoerythrin/chlorophyll fluorescence ratio was lower within the enriched patch than in naturally occurring phytoplankton patches outside of the enriched region. (4) No above-background chromorophoric dissolved organic matter (CDOM) fluorescence was observed in the enriched patch. Elevated CDOM fluorescence was associated with some of the naturally occurring phytoplankton patches outside the enriched region, while other such phytoplankton patches showed no measurable increase in CDOM over background levels. (5) The surface layer manifestation of the patch was observed to be transported to the north and west in close agreement with the drogue positions. No elevated surface layer chlorophyll fluorescence was seen in the vicinity of the ship as it sampled the submerged fraction at the time of the 30 October and 1 November overflights. The phycoerythrin pigment fluorescence emission was insensitive to ambient cloud-induced downwelling irradiance variability, while at the

  6. Paleoceanography and the diachrony of radiolarian events in the eastern equatorial Pacific

    Science.gov (United States)

    Moore, T. C.; Skackleton, N. J.; Pisias, N. G.

    1993-10-01

    The development of an orbitally tuned time scale for the ODP leg 138 sites provides biostratigraphers a very high resolution chronostratigraphic framework. With this framework we are better able to define which of the first and last appearances of species appear to be synchronous. In addition, the geographic distribution of sites provides the means with which the detailed spatial patterns of invasion of new species and the extinction of older species can be mapped. These maps not only provide information on the process of evolution, migration, and extinction, they can also be related to water mass distributions and near-surface circulation of the ocean. Of 39 radiolarian events studied at 11 sites in the eastern equatorial Pacific, 28 were found to have a minimum range in their estimated age that exceeded 0.15 m.y. The temporal pattern of first and last appearances of these diachronous events have coherent spatial patterns that indicate shifts in the areas of high oceanographic gradients over the past 10 Ma. These changes in the locations of high gradient regions suggest that the South Equatorial Current (SEC) was north of its present position prior to approximately 7 Ma. There was a southward shift in the northern boundary of this current between approximately 6 and 7 Ma, and the development of a relatively strong gradient between the northeastern and northwestern sites. Between approximately 3.7 and 3.4 Ma, there was a very slight northward shift in the northern boundary of the SEC and the steep gradients between the northeastern and northwestern sites may have disappeared. This change is thought to be associated with the closing of the Isthmus of Panama. The temporal-spatial patterns of diachronous events younger than 3.4 Ma are consistent with patterns of circulation in the modern ocean.

  7. Tropical Cyclone Exposure for U.S. waters within the Eastern Pacific Ocean basin, 1900-2013

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data represent modeled, historical exposure of U.S. offshore and coastal waters to tropical cyclone activity within the Eastern Pacific Ocean basin. BOEM Outer...

  8. CTD and Water Chemistry data of the Eastern Pacific Redox Experiment of May - June 2000 (NODC Accession 0000833)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Eastern Pacific Redox Experiment (EPREX) took place 24 May to 28 June 2000 on the R/V Roger Revelle. The first station was at the Hawaii Ocean Time Series...

  9. Variability of subduction rates of the subtropical North Pacific mode waters

    Institute of Scientific and Technical Information of China (English)

    HU Haibo; LIU Qinyu; ZHANG Yuan; LIUT Wei

    2011-01-01

    The climatology subduction rate for the entire Pacific is known,but the mechanism of interannual to decadal variation remains unclear.In this study,we calculated the annual subduction rates of three types of North Pacific subtropical mode waters using a general circulation model (LICOM 1.0)for the period of 1958-2001.The model experiments focused on interarnual variations of ocean dynamical processes under daily wind forcings and seasonal heat fluxes.The mode water formation region was defined by a potential vorticity minimum at outcrop locations.The model results show that two subduction rate maxima (>100 m/a) were located in the Subtropical Mode Water (STMW) and the Central Mode Water (CMW) formation regions.These regions are consistent with a climatologically calculated value.The subduction rate in the Eastern Subtropical Mode Water (ESTMW) formation region was smaller at about 75 m/a.The subduction rate shows clear interannual and decadal variations associated with oceanic dynamic variabilities.The average subduction rate of the STMW was much smaller during the period of 1981-1990 compared with other periods,while that of the CMW had a negative anomaly before 1975 and a positive anomaly after 1978.The variability agreed with Ekman and geostrophic advections and mixed layer depths.The interannual variability of the subduction rate for the ESTMW was smallest during 1970-1990,as a result of a weak wind stress curl.This paper explores how interannual signals from the atmosphere are stored in different parts of the ocean,and thus may contribute to a better understanding of feedback mechanisms for the Pacific Decadal Oscillation (PDO) event.

  10. Catalog of strong motion stations in Eastern North America

    Science.gov (United States)

    Busby, R. W.

    1990-04-01

    The catalog contains information on all strong motion stations operating in Eastern North America known to the National Center for Earthquake Engineering Research (NCEER). The location, coordinates, installation dates, type of instrument, operator, structure type and size, and site geology are listed for each station. The format of the catalog is patterned after the United States Geological Survey (USGS) Open-File Report 81-664, 'Western Hemisphere Strong-Motion Accelerograph Station List-1980' but the entries have been updated as of January 1990. There are 237 stations listed in the catalog which include 414 recording instruments. One third of these stations are intended to record free-field ground motion while the rest are associated with large engineered structures. The relationship of station location to seismicity is shown in a series of figures and a method is described to predict peak acceleration levels from an earthquake where the magnitude and distance to station are known.

  11. Late Quaternary Alluvial Fans of Southern Baja California, Mexico: Relation to Eastern Pacific Tropical Cyclones

    Science.gov (United States)

    Antinao, J.; McDonald, E.

    2009-12-01

    In the arid, non-glaciated regions of the Southwestern USA and Northwestern Mexico, aggradation in alluvial fan systems has been traditionally linked to cold and humid periods (e.g., Last Glacial Maximum) or to the transition to warm periods (e.g., the Pleistocene-Holocene transition, PHT). However, major intervals of sediment transport and aggradation have also occurred during climatically warm periods in these regions. These periods have also been identified as portraying enhanced humidity or “monsoonal’ conditions. Investigations on the weather systems able to perform geomorphic work during predominantly warm periods, i.e. the North American Monsoon (NAM) and Eastern Pacific (EP) Tropical Cyclones (TCs), have concentrated mainly in the USA. To understand the relative contribution of these systems to sediment transport over millennial timescales, we have mapped and characterized preliminarily the alluvial fans in four different areas of the Southern Baja California peninsula, Mexico. This region is dominated by EPTC precipitation, which in turn is driving the sediment transport along alluvial channels. Detailed geomorphologic mapping shows that a distinct Late Quaternary chronostratigraphy of alluvial fan units can be developed using geochronological and pedological tools. Specifically, a soil chronosequence can be compared to sequences in the SW USA, allowing a correlation to Late Pleistocene - Holocene events in the region. At least five alluvial units can be identified. Older units have well defined gravel pediments, Av and B horizons and pervasive pedogenic carbonate morphology, with alluvial terraces that rise tens of meters above the present channel. Intermediate age units have developed B horizons and carbonate morphology at different stages. The younger units have thin soil horizons, no carbonate morphology in the soil profile, and some of them are subject to episodic flooding during TC activity. The chronosequence developed is the first step towards

  12. Evidence of Enhanced Respired Carbon in Eastern Equatorial Pacific Deep-Waters over the last 30,000 years

    Science.gov (United States)

    Umling, N. E.; Thunell, R.

    2016-12-01

    Rapid decreases in glacial deep water reservoir ages have been observed in the Eastern Equatorial Pacific (EEP; this study), North Pacific (Rae et al., 2014), Southwest Pacific (Sikes et al., 2016), and North Atlantic (Skinner et al., 2013). It has been hypothesized that release of a deep ocean 14C-depleted, respired-carbon reservoir to the surface ocean and atmosphere is the most likely mechanism for the observed increases in atmospheric CO2 concentrations recorded in ice cores during the last glacial-interglacial transition (Broecker and Barker, 2007). This study examines whether oxygenation, organic carbon flux, and carbonate chemistry in the EEP deep-waters reflect an increase in respired carbon associated with recorded 14C-depletions using isotopic and trace element records from three Panama Basin cores (2,650-3,200 m water-depth). An increase in glacial deep-water respired carbon storage would result in a shift of DIC speciation towards lower carbonate ion concentrations along with deoxygenation of bottom waters. Specifically, we use the boron to calcium (B/Ca) and uranium to calcium (U/Ca) ratios of the benthic foraminifera Cibicidoides wuellerstorfi to reconstruct deep-water carbonate ion concentration (Yu and Elderfield, 2007; Raizsch et al., 2011). Additionally, bottom water oxygenation is estimated from the difference in δ13C of benthic foraminifera living in pore waters at the anoxic boundary and of those living in bottom water (Δ δ13C; Hoogakker et al., 2015, 2016), while carbon flux was assessed from the U/Ca and Cd/Ca of foraminiferal authigenic coatings.

  13. Preandean geological configuration of the eastern North Patagonian Massif, Argentina

    Directory of Open Access Journals (Sweden)

    Daniel A. Gregori

    2013-11-01

    Full Text Available The Preandean geological configuration of the eastern North Patagonian Massif is established through the use of geological and geophysical analysis. The positive gravity anomalies located near the Atlantic coast are due to 535 and 540 Ma old rocks belonging to the Pampean Orogeny (Precambrian–middle Cambrian, which are widely recognized in central and northern Argentina. The Famatinian Cycle (Ordovician–Devonian is represented by a Silurian–Devonian marine basin equivalent to those of eastern-central Argentina and South Africa, and which was deformed at the end of the Devonian by an ∼E–W to WNW–ESE compressional event, part of the Famatinian Orogeny. Containing strong gravity gradients, the NW–SE belt is coincident with fault zones which were originated during the Gondwanide Orogeny. This event also produced NW–SE overthrusting of the Silurian–Devonian sequences and strike-slip faults that displaced blocks in the same direction. This deformation event belongs to the Gondwanide Orogeny that includes movements related to a counterclockwise rotation of blocks in northern Patagonia. The strong negative anomalies located in the western part of the area stem from the presence of rocks of the Jurassic Cañadón Asfalto basin interbedded in the Marifil Complex. These volcaniclastic sequences show mild deformation of accommodation zones in a pre-Jurassic paleorelief.

  14. The flow field of the upper hypoxic Eastern Tropical North Atlantic oxygen minimum zone

    Directory of Open Access Journals (Sweden)

    L. Stramma

    2015-09-01

    Full Text Available A subsurface low oxygen zone is located in the eastern tropical North Atlantic Ocean (ETNA in the upper ocean with the core of the hypoxic (O2 ≤ 60 μmol kg−1 oxygen minimum zone (OMZ at 400 to 500 m depth. The poorly known subsurface circulation in the OMZ region is derived from observations and data assimilation results. Measurements in the eastern tropical North Atlantic in November/December 2008, in November/December 2009 and October/November 2010 of velocity, oxygen and of a tracer (CF3SF5 that was released in April 2008 at ∼ 8° N, 23° W (at ∼ 330 m depth show circulation in the upper part of the OMZ with spreading to the east in the North Equatorial Countercurrent (NECC region and northwestward around the Guinea Dome. Three floats equipped with oxygen sensors deployed at ∼ 8° N, 23° W with parking depths at 330, 350 and 400 m depths were used to estimate velocity along the float trajectory at the surface and at the park depth. South of 9° N, the zonal surface velocity estimate from float data alternate seasonally. At the 350 m park depth north of 9° N a cyclonic northwestward flow across the OMZ was observed. The northward shift into the upper OMZ and the cyclonic flow around the Guinea Dome seem to be connected to a strong Atlantic Meridional Mode (AMM event in 2009. A near-surface cyclonic circulation cell east of the Cape Verde Islands expands into the OMZ layer. The circulation of the upper OMZ mirrors the near surface circulation. Oxygen measurements from the cruises used here, as well as other recent cruises up to the year 2014 confirm the continuous deoxygenation trend in the upper OMZ since the 1960's near the Guinea Dome. The three floats deployed with the tracer show spreading paths consistent with the overall observed tracer spreading. Mesoscale eddies may modify the oxygen distribution in the OMZs. Oxygen sensors on the floats remained well calibrated for more than 20 months and so the oxygen profiles can be

  15. Arcane epipelagic fishes of the subtropical North Pacific and factors associated with their distribution

    Science.gov (United States)

    McKinnell, Skip; Seki, Michael P.

    2017-01-01

    In 1992, a moratorium was declared by the United Nations General Assembly to end the practice of large-scale pelagic driftnet fishing. During two years leading up to the moratorium, three scientific research and fishery observer programs involving Canada, Japan, Korea, China-Taipei and the United States had collected significant amounts of information about the distribution and abundance of the epipelagic fauna in the subtropical North Pacific Ocean. The pan-regional distributions of the fishes in 1990 and 1991, most of which were taken as bycatch in 9910 fishing operations (357,150 km of driftnet) are described. More species were observed per fishing operation in 1991 than in 1990. Principal coordinate analysis of the incidence of the commonly caught fish species was used to show that, except for an anomaly in the region of the Shatsky Rise (165°E), the composition of the catch changed from the coast of Japan across more than 6000 km to the eastern boundary of the fishery (145°W). The analysis suggested that the fish species composition changed rather little with increasing latitude within the southern part of the domain (25-35°N), before changing more rapidly north of the Kuroshio Extension region to a more subarctic, transition zone fauna.

  16. A Probabilistic Model of Illegal Drug Trafficking Operations in the Eastern Pacific and Caribbean Sea

    Science.gov (United States)

    2013-09-01

    Illicit drug - trafficking is a major concern of the United States and is a primary pillar of President Barack Obama’s Strategy to Combat Transnational...Organized Crime. In the eastern Pacific and Caribbean Sea, drug - trafficking organizations operate a variety of vessels to transit drugs from South...interdicts illegal drug - trafficking in this region. In this thesis, we develop a probability model based on intelligence inputs to generate a spatial

  17. Status of the eastern Pacific agujon needlefish Tylosurus pacificusz (Steindachner, 1876) (Beloniformes: Belonidae)

    OpenAIRE

    Collette, Bruce B.; Branford, Heidi M.

    2016-01-01

    Tylosurus pacificus (Steindachner, 1876) is confirmed to have full species rank based on: 1) sympatry with T. acus melanotus at Isla Gorgona and in Panamá; 2) level of morphological differentiation in numbers of vertebrae, dorsal and anal fin rays; and 3) level of mtDNAdifferentiation. The eastern Pacific agujon needlefish is found from the Gulf of California, Mexico, to Peru, including the Galápagos Islands. Se confirma que Tylosurus pacificus (Steindachner, 1876) tiene el rango de especi...

  18. First record in the Tropical Eastern Pacific of the exotic species Ficopomatus uschakovi (Polychaeta, Serpulidae

    Directory of Open Access Journals (Sweden)

    Rolando Bastida Zavala

    2012-11-01

    Full Text Available The exotic Indo-West-Pacific species, Ficopomatus uschakovi (Polychaeta, Serpulidae is recorded for the first time in the Tropical Eastern Pacific from two sites in La Encrucijada Biosphere Reserve, Chiapas, a coastal lagoon in the Pacific south of Mexico. The means of dispersal of this serpulid species still remains unclear, as the nearest port (Puerto Chiapas is 70 km to the south, and there are no port installations or shrimp cultures in the lagoon. The record of this serpulid species, apparently widely distributed in this coastal lagoon, has implications regarding possible effects on the brackish-water ecosystem, since the invasion event very well may have occurred several years ago. It is recommended that an exhaustive study be carried out in the coastal lagoons of Chiapas to evaluate the real distribution and the effects of this invasive species on the ecosystem. A complete description, including photographs and drawings, is provided.

  19. First record in the Tropical Eastern Pacific of the exotic species Ficopomatus uschakovi (Polychaeta, Serpulidae).

    Science.gov (United States)

    Bastida-Zavala, Rolando; García-Madrigal, Socorro

    2012-01-01

    The exotic Indo-West-Pacific species, Ficopomatus uschakovi (Polychaeta, Serpulidae) is recorded for the first time in the Tropical Eastern Pacific from two sites in La Encrucijada Biosphere Reserve, Chiapas, a coastal lagoon in the Pacific south of Mexico. The means of dispersal of this serpulid species still remains unclear, as the nearest port (Puerto Chiapas) is 70 km to the south, and there are no port installations or shrimp cultures in the lagoon. The record of this serpulid species, apparently widely distributed in this coastal lagoon, has implications regarding possible effects on the brackish-water ecosystem, since the invasion event very well may have occurred several years ago. It is recommended that an exhaustive study be carried out in the coastal lagoons of Chiapas to evaluate the real distribution and the effects of this invasive species on the ecosystem. A complete description, including photographs and drawings, is provided.

  20. First record in the Tropical Eastern Pacific of the exotic species Ficopomatus uschakovi (Polychaeta, Serpulidae)

    Science.gov (United States)

    Bastida-Zavala, Rolando; García-Madrigal, Socorro

    2012-01-01

    Abstract The exotic Indo-West-Pacific species, Ficopomatus uschakovi (Polychaeta, Serpulidae) is recorded for the first time in the Tropical Eastern Pacific from two sites in La Encrucijada Biosphere Reserve, Chiapas, a coastal lagoon in the Pacific south of Mexico. The means of dispersal of this serpulid species still remains unclear, as the nearest port (Puerto Chiapas) is 70 km to the south, and there are no port installations or shrimp cultures in the lagoon. The record of this serpulid species, apparently widely distributed in this coastal lagoon, has implications regarding possible effects on the brackish-water ecosystem, since the invasion event very well may have occurred several years ago. It is recommended that an exhaustive study be carried out in the coastal lagoons of Chiapas to evaluate the real distribution and the effects of this invasive species on the ecosystem. A complete description, including photographs and drawings, is provided. PMID:23226707

  1. An intimate coupling of ocean-atmospheric interaction over the extratropical North Atlantic and Pacific

    Science.gov (United States)

    Li, Chun; Wu, Lixin; Wang, Qi; Qu, Liwei; Zhang, Liping

    2009-05-01

    The inter-basin teleconnection between the North Atlantic and the North Pacific ocean-atmosphere interaction is studied using a coupled ocean-atmosphere general circulation model. In the model, an idealized oceanic temperature anomaly is initiated over the Kuroshio and the Gulf Stream extension region to track the coupled evolution of ocean and atmosphere interaction, respectively. The experiments explicitly demonstrate that both the North Pacific and the North Atlantic ocean-atmosphere interactions are intimately coupled through an inter-basin atmospheric teleconnection. This fast inter-basin communication can transmit oceanic variability between the North Atlantic and the North Pacific through local ocean-to-atmosphere feedbacks. The leading mode of the extratropical atmospheric internal variability plays a dominant role in shaping the hemispheric-scale response forced by oceanic variability over the North Atlantic and Pacific. Modeling results also suggest that a century (two centuries) long observations are necessary for the detection of Pacific response to Atlantic forcings (Atlantic response to Pacific forcing).

  2. The 18.6-year period moon-tidal cycle in Pacific Decadal Oscillation reconstructed from tree-rings in western North America

    Science.gov (United States)

    Yasuda, Ichiro

    2009-03-01

    Time-series of Pacific Decadal Oscillation (PDO) reconstructed from tree-rings in Western North America is found to have a statistically significant periodicity of 18.6-year period lunar nodal tidal cycle; negative (positive) PDO tends to occur in the period of strong (weak) diurnal tide. In the 3rd and 5th (10th, 11th and 13rd) year after the maximum diurnal tide, mean-PDO takes significant negative (positive) value, suggesting that the Aleutian Low is weak (strong), western-central North Pacific in 30-50°N is warm (cool) and equator-eastern rim of the Pacific is cool (warm). This contributes to climate predictability with a time-table from the astronomical tidal cycle.

  3. Eelgrass (Zostera marina) Microsatellite DNA Data; Pacific Coast of North America, 2000-2009

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set contains genetic information collected from eelgrass (Zostera marina) populations along the Pacific coast of North America from Alaska to Baha...

  4. Climate Prediction Center (CPC) Monthly Pacific North American Teleconnection Pattern Index

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Monthly tabulated index of the Pacific/ North American teleconnection pattern. The data spans the period 1950 to present. The index is derived from a rotated...

  5. AFSC/NMML: North Pacific Right Whale Vessel Surveys in the Southeastern Bering Sea, 2007 - 2011

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The North Pacific right whale (NPRW) was heavily hunted between the 17th and the 20th centuries. Protection was supposedly afforded by international treaties in the...

  6. Understanding TEX86H Temperature Estimates in the Eastern Equatorial Pacific over the Last Deglacial

    Science.gov (United States)

    Randle, N. J.; Schmidt, M. W.; Bianchi, T. S.; Hertzberg, J. E.; Shields, M. R.

    2014-12-01

    An index based on the relative abundance of glycerol dialkyl glycerol tetraethers (TEX86) has been gaining support for use as a sea surface temperature proxy. It has had limited application in the Eastern Equatorial Pacific (EEP) and, prior to this study, has not been applied to a high-resolution record within this region. Here, we utilize the TEX86H temperature index to calculate a North-South temperature gradient in the EEP over the last ~25 kyr using two sediment cores, MV1014-02-17JC (located within the equatorial upwelling zone on the Carnegie Ridge) and MV1014-01-08JC (located North of the seasonal upwelling region on the Cocos Ridge). During the Late Holocene, the Cocos Ridge exhibited warmer TEX86H temperatures as compared to the Carnegie Ridge. The TEX86H calculated temperatures are within analytical error of both modern annual sea surface temperatures at each site and Mg/Ca-based SST estimates derived from Globigerinoides ruber. From 5.6 kyr to 8.5 kyr there is an abrupt ~3°C decrease in the TEX86H temperatures at the Cocos Ridge, marking a breakdown in the N-S temperature gradient. Then, similar TEX86H temperatures are calculated through the Early Holocene and into the deglacial as both sites cool into the Last Glacial Maximum (LGM). Interestingly, the temperature gradient switches during the LGM, with the Carnegie Ridge yielding temperatures 1-2°C warmer than the Cocos Ridge. This gradient reversal, in contrast, is not seen in the limited Mg/Ca temperatures measured during the LGM in the same core intervals. Instead, the calculated TEX86H temperatures from both sites are cooler than calculated Mg/Ca-SSTs from the near-surface dwelling planktonic foraminifera G. ruber. Additional foraminiferal Mg/Ca and stable isotope analyses will also be presented in an effort to better constrain deglacial changes in upper water column hydrography at both sites.

  7. 78 FR 34347 - Endangered and Threatened Species; Recovery Plan for the North Pacific Right Whale

    Science.gov (United States)

    2013-06-07

    ... Plan for the North Pacific Right Whale AGENCY: National Marine Fisheries Service, National Oceanic and... Pacific right whale (Eubalaena japonica). ADDRESSES: Electronic copies of the Final Recovery Plan are... the development of recovery plans for each ] listed species unless such a plan would not promote...

  8. Changes in storm track and precipitation variability in East Asia and western North Pacific related to the MJO during boreal winter under global warming

    Science.gov (United States)

    Takahashi, C.; Shirooka, R.

    2013-12-01

    The present study examines the change in precipitation intensity and storm track activity (STA) influenced by Madden-Julian oscillation (MJO) in response to global warming in East Asia and western North Pacific during the boreal winter using CMIP5 models. The synoptic eddy activity and precipitation intensity are enhanced (suppressed) with the MJO in the tropical Indian Ocean (western Pacific). Several models have relatively good representation of MJO precipitation characteristics with high skill score (BEST models). In the present climate simulation (the latter half of 20th century), the BEST models ensemble produce weaker amplitude of upper-atmospheric circulations in the western North Pacific associated with the MJO in the Indian Ocean. This result arises from the weakened Rossby wave response excited by the MJO convective heating due to the reduced amplitude of MJO precipitation in the western Pacific. In the future climate (the late 21st century) projection, BEST models exhibit increased amplitude of MJO rainfall in the tropical Indian Ocean and western Pacific. The STA in the western North Pacific related to the MJO in the Indian Ocean intensify in the future warming climate. The intensification of STA corresponds to the increased lower-atmospheric meridional eddy heat flux. The analysis shows their intensifications correspond to the strengthened intraseasonal baroclinicity in the western North Pacific influenced by the MJO. BEST models project increase of precipitation over eastern China and Japan in East Asia. The diagnosis of the moisture budget indicate that this precipitation change is attributed to the increases of moisture flux due to mean moisture advection by strengthened anomalous intraseasonal southerly flow. On the other hand, the mean moisture convergence by anomalous intraseasonal flows and sea surface evaporation contribute to the increased precipitation over the subtropical western Pacific. These results suggests that correct projection in the

  9. Contrasting the eastern Pacific El Niño and the central Pacific El Niño: process-based feedback attribution

    Science.gov (United States)

    Hu, Xiaoming; Yang, Song; Cai, Ming

    2016-10-01

    This paper examines the roles of radiative and non-radiative air-sea coupled thermodynamic processes in modifying sea surface temperature (SST) anomalies driven by (air-sea coupled) oceanic dynamic processes, focusing on their contributions to the key differences between the eastern Pacific (EP) El Niño and the central Pacific (CP) El Niño. The attribution is achieved by decomposing SST anomalies into partial temperature anomalies due to individual processes using a coupled atmosphere-surface climate feedback-response analysis method. Oceanic processes induce warming from the central to the eastern equatorial Pacific and cooling over the western basin with a maximum warming center in the central Pacific for both types of El Niño. The processes that act to oppose the oceanic process-induced SST anomalies are surface latent heat flux, sensible heat flux, cloud, and atmospheric dynamic feedbacks, referred to as negative-feedback processes. The cooling due to each of the four negative-feedback processes is the strongest in the region where the initial warming due to oceanic processes is the largest. Water-vapor feedback is the sole process that acts to enhance the initial warming induced by oceanic processes. The increase in atmospheric water vapor over the eastern Pacific is much stronger for the EP El Niño than for the CP El Niño. It is the strong water-vapor feedback over the eastern Pacific and the strong negative feedbacks over the central equatorial Pacific that help to relocate the maximum warming center from the central Pacific to the eastern basin for the EP El Niño.

  10. Bifurcation of Pacific North Equatorial Current at the surface

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The grid altimetry data between 1993 and 2006 near the Philippines were analyzed by the method of Empirical Orthogonal Function (EOF) to study the variation of bifurcation of the North Equatorial Current at the surface of the Pacific. The relatively short-term signals with periods of about 6 months, 4 months, 3 months and 2 months are found besides seasonal and interannual variations mentioned in previous studies. Local wind stress curl plays an important role in controlling variation of bifurcation latitude except in the interannual timescale. The bifurcation latitude is about 13.3°N in annual mean state and it lies at the northernmost position (14.0°N) in January, at the southernmost position (12.5°N) in July. The amplitude of variation of bifurcation latitude in a year is 1.5°, which can mainly be explained as the contributions of the signals with periods of about 1 year (1.2°) and 0.5 year (0.3°).

  11. Metal concentrations in pelagic seabirds from the North Pacific Ocean.

    Science.gov (United States)

    Honda, K; Marcovecchio, J E; Kan, S; Tatsukawa, R; Ogi, H

    1990-01-01

    Concentrations of four essential elements (Fe, Mn, Zn, and Cu) and two toxic metals (Cd and Hg) were measured in selected tissues of 19 pelagic seabird species collected in the North Pacific and neighboring waters. Essential metal concentrations were generally highest in the liver and less variable than toxic metals among species and also within each species. Fe concentrations in the muscle were higher in Alcidae than in the other families, whereas the opposite trend was found for Fe and Mn in the liver. Zn concentrations varied among species, depending on the Cd concentrations. On the other hand, toxic metal concentrations were highest in the liver or kidney and varied widely among species, greatly depending on differences in the diet among species. Extraordinarily high Hg concentrations were found in Black-footed Albatrosses,Diomedea nigripes, exceeding 300 μg/g wet weight in some, and seemed to be due to constraints on the elimination of Hg. Also, some geographical differences in Cd and Hg concentrations of the seabirds were observed. The concentrations of Cd and Hg reported here, however, seem to be natural rather than due to environmental pollution.

  12. North Pacific Acoustic Laboratory: Deep Water Acoustic Propagation in the Philippine Sea

    Science.gov (United States)

    2013-09-30

    relatively benign northeast and north central Pacific Ocean. During 2009–2011 the methods developed to study long-range, deep water broadband...These papers include results from the 2004–2005 NPAL experiment in the central North Pacific, in addition to results from the NPAL Philippine Sea...PERFORMANCE BY MAN” Award Universidad Autonoma de Baja California, Facultad de Ciencias Marinas (Ensenada, Mexico) XXI Student Congress (May 14–16, 2013) W. H

  13. Seasonal Variability of Extratropical North Pacific Wind Stress, Ekman Pumping and Sverdrup Transport

    Science.gov (United States)

    2001-12-01

    The annual cycle of the North Pacific wind stress , Ekman pumping and Sverdrup transport is investigated by means of empirical orthogonal function... stress components. These wind stress components are averaged to 624 monthly mean fields from which monthly mean Ekman pumping and Sverdrup transport...Research (NCAR) Reanalysis daily averaged surface wind components covering the extratropical North Pacific are used to calculate daily averaged wind

  14. 78 FR 23634 - Union Pacific Railroad Company-Trackage Rights Exemption-Elgin, Joliet and Eastern Railway Company

    Science.gov (United States)

    2013-04-19

    ... Surface Transportation Board Union Pacific Railroad Company--Trackage Rights Exemption--Elgin, Joliet and Eastern Railway Company Pursuant to a written trackage rights agreement dated December 18, 2012, Elgin, Joliet and Eastern Railway Company (EJ&E) \\1\\ has agreed to grant overhead trackage rights to Union...

  15. Alpine ice core records from Pacific North America

    Science.gov (United States)

    Steig, E. J.; Clark, D. H.; Pettit, E.

    2006-12-01

    Climate in the northeast Pacific shows significant multi-decadal and longer timescale variability, yet the instrumental record in western North America is relatively short. Paleoclimate proxy data, therefore, are essential to understanding climate variability in this region. A number of promising proxy-based reconstructions have been published recently, but additional constraints are needed. Ice core records are particularly useful for these reconstructions because they provide both high-resolution proxy data (such as δ18O and ion concentrations, which reflect large scale circulation changes) and direct measures of snow accumulation. Furthermore, at high altitude sites where ablation rates are small, snow accumulation is a highly reliable measure of total precipitation. At Mt. Logan, St. Elias Range, Yukon Territory, annual accumulation is significantly correlated with large scale climate indices such as the Aleutian Low pressure index. Perhaps more importantly, annual layer thickness in the Mt. Logan core is demonstrably reliable as an indicator of wintertime accumulation extremes not just at the site, but over a fairly large geographic area. Similar records have also been obtained at Mt. Churchill-Bona (AK) and Eclipse Dome (YT), also in the Wrangell/St. Elias range. A sufficiently complete spatial network of cores could in principle be used to develop a robust estimate of past winter precipitation variability across western Canada and Alaska. Mt. Waddington, British Columbia Coast Range, is one of the most promising sites for an ice core at temperate latitudes in North America. Mt. Waddington's location is highly complementary to the Wrangell/St. Elias sites: precipitation, temperature and geopotential height anomalies all tend to be opposite in sign in the two geographic regions. An accumulation record from Waddington, therefore, has considerable potential for refining reconstructions of precipitation and large scale circulation across the region. In July 2006

  16. Distribution of dissolved zinc in the western and central subarctic North Pacific

    Science.gov (United States)

    Kim, T.; Obata, H.; Gamo, T.

    2016-02-01

    Zinc (Zn) is an essential micronutrient for bacteria and phytoplankton in the ocean as it plays an important role in numerous enzyme systems involved in various metabolic processes. However, large-scale distributions of total dissolved Zn in the subarctic North Pacific have not been investigated yet. In this study, we investigated the distributions of total dissolved Zn to understand biogeochemical cycling of Zn in the western and central subarctic North Pacific as a Japanese GEOTRACES project. Seawater samples were collected during the R/V Hakuho-maru KH-12-4 GEOTRACES GP 02 cruise (from August to October 2012), by using acid-cleaned Teflon-coated X-type Niskin samplers. Total dissolved Zn in seawater was determined using cathodic stripping voltammetry (CSV) after UV-digestion. In this study, total dissolved Zn concentrations in the western and central subarctic North Pacific commonly showed Zn increase from surface to approximately 400-500 m, just above the oxygen minimum layer. However, in the western subarctic North Pacific, relatively higher Zn concentrations have also been observed at intermediate depths (800-1200 m), in comparison with those observed in deep waters. The relationship between Zn and Si in the western subarctic North Pacific showed that Zn is slightly enriched at intermediate depths. These results may indicate that there are additional sources of Zn to intermediate water of the western subarctic North Pacific.

  17. Possible Ballast Water Transfer of Lionfish to the Eastern Pacific Ocean

    OpenAIRE

    MacIsaac, Hugh J.; De Roy, Emma M.; Leung, Brian; Grgicak-Mannion, Alice; Ruiz, Gregory M.

    2016-01-01

    The Indo-Pacific Red Lionfish was first reported off the Florida coast in 1985, following which it has spread across much of the SE USA, Gulf of Mexico, and Caribbean Sea. Lionfish negatively impact fish and invertebrate assemblages and abundances, thus further spread is cause for concern. To date, the fish has not been reported on the Pacific coast of North or Central America. Here we examine the possibility of ballast water transfer of lionfish from colonized areas in the Atlantic Ocean to ...

  18. Convection and Easterly Waves Observed in the Eastern Pacific ITCZ During EPIC2001

    Science.gov (United States)

    Petersen, Walter A.; Cifelli, Robert; Boccippio, Dennis J.; Rutledge, Steven A.; Arnold, James E. (Technical Monitor)

    2002-01-01

    During the last three weeks of September 2001, the East Pacific Investigation of Climate Processes in the Coupled Ocean-Atmosphere System (EPIC2001) intensive field campaign focused on studies of deep convection in the ITCZ-cold tongue complex over the Mexican warm-pool region (10 deg. N 95 deg. W) of the eastern Pacific Ocean. Major observational platforms deployed during this phase of EPIC2001 included two ships, the NOAA R/V Ronald H. Brown and the NSF R/V Horizon, and two research aircraft including a NOAA P-3 and the NCAR C-130. This study utilizes new C-band Doppler radar and sounding observations collected aboard the R/V Ronald Brown to describe the 4-D structure of ITCZ convection as a function of the environmental forcing and phase of 3-5 day easterly wave passages. Three distinct easterly wave passages occurred during EPIC2001. Each wave originated in the eastern Atlantic Ocean and after moving over Central America and into the eastern Pacific, were easily identified in time-height profiles of wind and thermodynamic data collected at the position of the R/V Brown. In all cases, the wave trough axes (as defined by changes in the meridional and zonal wind direction and changes in pressure altitude) exhibited relatively weak shear at low to mid-levels and tilted westward with height. The humidity profile in each wave did not exhibit as great a tilt in the vertical as the trough axes. Consistent with previous studies of westward tilting waves over the western Pacific Ocean, peaks in radar diagnosed rainfall tended to lead the passage of the surface wave trough by 0-2 days.

  19. Convection and Easterly Waves Observed in the Eastern Pacific ITCZ During EPIC2001

    Science.gov (United States)

    Petersen, Walter A.; Cifelli, Robert; Boccippio, Dennis J.; Rutledge, Steven A.; Arnold, James E. (Technical Monitor)

    2002-01-01

    During the last three weeks of September 2001, the East Pacific Investigation of Climate Processes in the Coupled Ocean-Atmosphere System (EPIC2001) intensive field campaign focused on studies of deep convection in the ITCZ-cold tongue complex over the Mexican warm-pool region (10 deg. N 95 deg. W) of the eastern Pacific Ocean. Major observational platforms deployed during this phase of EPIC2001 included two ships, the NOAA R/V Ronald H. Brown and the NSF R/V Horizon, and two research aircraft including a NOAA P-3 and the NCAR C-130. This study utilizes new C-band Doppler radar and sounding observations collected aboard the R/V Ronald Brown to describe the 4-D structure of ITCZ convection as a function of the environmental forcing and phase of 3-5 day easterly wave passages. Three distinct easterly wave passages occurred during EPIC2001. Each wave originated in the eastern Atlantic Ocean and after moving over Central America and into the eastern Pacific, were easily identified in time-height profiles of wind and thermodynamic data collected at the position of the R/V Brown. In all cases, the wave trough axes (as defined by changes in the meridional and zonal wind direction and changes in pressure altitude) exhibited relatively weak shear at low to mid-levels and tilted westward with height. The humidity profile in each wave did not exhibit as great a tilt in the vertical as the trough axes. Consistent with previous studies of westward tilting waves over the western Pacific Ocean, peaks in radar diagnosed rainfall tended to lead the passage of the surface wave trough by 0-2 days.

  20. Electrophoretic enzyme analysis of North American and eastern Asian populations of Agastache sect. Agastache (Labiatae)

    Science.gov (United States)

    Vogelmann, James E.; Gastony, Gerald J.

    1987-01-01

    Genetic relationships among the seven species of Agastache sect. Agastache common in North America and the one found in eastern Asia were assessed using starch-gel electrophoresis of twelve enzymatic proteins. Nei's (1976) genetic distance and identity values, calculated among the 32 populations used in this study, partitioned the Agastache section into four discrete groups: (1) A. nepetoides (eastern North America), (2) A. scrophulariifolia and A. foeniculum (eastern and central North America), (3) the four species of the western U.S. (A. urticifolia, A. occidentalis, A. parvifolia, and A. cusickii), and (4) A. rugosa (eastern Asia). The Asian Agastache, separated from its American congeners for over 12 million years, differed from American populations at only two (the IDH-1 and LAP-1 alleles) of the fifteen loci surveyed; these alleles were not found in any of the North American plants. Nei's genetic distances between the Asian and North American populations ranged from 0.2877 to 0.6734.

  1. 76 FR 71321 - North Pacific Fishery Management Council; Public Meetings

    Science.gov (United States)

    2011-11-17

    ... Operations and Procedures (SOPPs) review/approval and update on workshop with International Pacific Halibut... Service Report; Protected Species Report (including Steller Sea Lion (SSL) Center of Independent...

  2. 76 FR 2084 - North Pacific Fishery Management Council; Public Meetings

    Science.gov (United States)

    2011-01-12

    ... discussion paper and TRAWLEX report). Alaska Department of Fish & Game Report. International Pacific Halibut... Species Report (including update on Steller Sea Lion (SSL); Endangered Species Act (ESA) listed...

  3. North Pacific-wide spreading of isotopically heavy nitrogen from intensified denitrification during the Bølling/Allerød and post-younger dryas periods: evidence from the Western Pacific

    Directory of Open Access Journals (Sweden)

    S. J. Kao

    2008-03-01

    Full Text Available Sedimentary δ15N record for the past 30 ka buried in the Okinawa Trough in the western North Pacific mimicking the pattern from the Eastern Tropical North Pacific (ETNP, but the values (4.4–5.8‰ and the amplitude of the variation were much smaller than those (9–17‰ of the previous site. All but three values in the record were lower than the mean δ15N (5.6‰ of nitrate in the upper 800 m of the Kuroshio water suggesting additional inputs of isotopically light nitrogen from N2-fixation. The peak values of δ15N occurred during the Bølling/Allerød period and the warming period right after the Younger Dryas, synchronous to those found in the Eastern North Pacific. It is highly probable the high δ15N values are originated from the influence of the intensified denitrification in the ETNP during the warming periods. These new data represent the sedimentary record most distant from the intensive denitrifying zone in the ETNP and may serve as critical constraints to better quantify the nitrogen budget in the last climate cycle.

  4. Ecological context for the North Pacific Landscape Conservation Cooperative

    Science.gov (United States)

    Woodward, Andrea; Taylor, Audrey; Weekes, Anne

    2012-01-01

    The North Pacific Landscape Conservation Cooperative (NPLCC) encompasses the temperate coastal rainforest and extends from the coastal mountains to the near-shore from the Kenai Peninsula, Alaska to Bodega Bay, California. The area spans multiple agency, state, and international boundaries over more than 22 degrees of latitude, including a wide range of type and intensity of human land-use activities. Development of NPLCC goals and administrative structures will be facilitated by a shared ecological context for discussing this expansive, diverse, and complex landscape. In support of activities to organize the NPLCC, we provided conceptual models to describe the ecological structure of the NPLCC. Recognizing that the boundaries of LCCs were primarily based on Level 2 of the hierarchical ecoregional classification of Omernik (Comission for Environmental Cooperation 1997), we used nested Level 3 ecoregions to define subregions within the NPLCC. Rather than develop conceptual models for all nine constituent subregions, we opted to consider five groups: Puget-Georgia Basin Lowland and Willamette Valley, Alaska-British Columbia Coast, Alaska-British Columbia Mountains, Klamath-Olympic-Cascade Mountains, and Washington-Oregon-Northern California Coast. At the conclusion of the project, we felt that the close relationship between mountain and coastal areas support combining them to create three major subregions: Alaska-British Columbia coast and mountains, Washington-Oregon-Northern California coast and mountains, and the lowlands of the Georgia Basin and Willamette Valley. The following figures present the Omernik Level 3 ecoregions comprising the NPLCC; how the ecoregions were grouped to create conceptual models; and conceptual models for each group. The five models each consist of a table listing resources, stressors, potential climate change impacts; a landcover map; and a cartoon to summarize the table and evoke the landscape. A final figure summarizes resources

  5. Reconstructing Winter North Pacific Sea-Level Pressure Anomalies Over the Past Three Centuries Using a New Calibration Method with the Eclipse and Mt. Logan Ice Cores

    Science.gov (United States)

    Kelsey, E. P.; Wake, C. P.; Osterberg, E. C.

    2012-12-01

    A deeper understanding of the behavior of North Pacific extratropical cyclones and anticyclones prior to the instrumental era is needed to advance our understanding of North Pacific climate variability. To help achieve this objective, we develop and use a new nonlinear ice core calibration procedure with the Eclipse (3017 m a.s.l.) and Mt. Logan (5400 m a.s.l.) ice core records from Yukon, Canada to isolate the ranges of ice core values that are consistently associated with North Pacific wintertime sea-level pressure (SLP) anomalies. Over the calibration period (1872-2001), each ice core record is ranked and divided into 10 groups of 13 years. Then for each group, the frequency of positive and negative SLP anomalies at each grid point is contoured and the composite mean SLP anomaly values are shaded. These plots elucidate areas where statistically significant SLP anomalies occur frequently in association with groups of ice core values. This new calibration procedure shows that the lowest and the two highest groups of Mt. Logan annual [Na+] are sensitive to SLP anomalies in the central and eastern Pacific and the second lowest [Na+] group is sensitive to western Pacific SLP anomalies. The highest and lowest Eclipse cold-season accumulation groups are most sensitive to SLP anomalies more distant in the western and central Pacific. This result is surprising in light of stable isotope studies suggesting a more distant moisture source for Mt. Logan. A reconstruction using these calibrated records indicates the Aleutian Low was predominantly weaker than average between 1699-1871. Our results highlight that having these geographically close ice core records is important to developing a deeper understanding of North Pacific climate variability.

  6. Bird collision impacts at wind turbines in eastern North America

    Energy Technology Data Exchange (ETDEWEB)

    Kerlinger, Paul; Curry, Richard; Guarnaccia, John [Curry and Kerlinger, LLC (United States)

    2011-07-01

    This paper discusses the incidence of bird collisions at wind turbines in Eastern North America. Modern wind turbines are high, with long, tubular towers. Bird fatality is analyzed and references to the relevant studies that have been done are given. 26 sites were investigated for turbine mortality in 2011 and these are shown on a map. 64 turbines were examined in Maple Ridge and it was seen that 4 birds were killed per turbine per year. The results demonstrated that no eagles were killed, there were no endangered species involved and there was no real deviation from site to site. More than 80,000 individual turbines were researched and more than $30 million spent on the study. Around 120,000 birds are killed per year, or an average of over 6 birds per turbine per year, in the United States. It is clear from the extensive research conducted that there are a lot of data on birds and turbines; the data show that songbirds are the most often affected.

  7. BrO measurements over the Eastern North-Atlantic

    Directory of Open Access Journals (Sweden)

    U. Platt

    2009-12-01

    Full Text Available The aim of the work presented here was to detect BrO in the marine boundary layer over the Eastern North-Atlantic by Multi AXis-Differential Optical Absorption Spectroscopy (MAX-DOAS of scattered sunlight. With this technique, information about the concentration and the vertical profile of trace gases in the atmosphere can be gained. BrO can be formed in the marine atmosphere by degradation of biogenic organohalogens or by oxidation of bromide in sea salt aerosol. BrO influences the chemistry in marine air in many ways, e.g. since it catalytically destroys ozone, changes the NO2/NO-ratio as well as the OH/HO2-ratio and oxidises DMS. However, the abundance and the significance of BrO in the marine atmosphere is not yet fully understood.

    We report on data collected during a ship cruise, which took place along the West African Coast in February 2007, within the framework of the Surface Ocean PRocesses in the ANthropocene project (SOPRAN. Tropospheric BrO could be detected during this cruise at peak mixing ratios of (10.2±3.7 ppt at an assumed layer height of 1 km on 18 February 2007. Furthermore, it was found that the mean BrO concentrations increased when cruising close to the African Coast suggesting that at least part of the BrO might have originated from there.

  8. Mercury sources, distribution, and bioavailability in the North Pacific Ocean: Insights from data and models

    Science.gov (United States)

    Sunderland, E.M.; Krabbenhoft, D.P.; Moreau, J.W.; Strode, S.A.; Landing, W.M.

    2009-01-01

    Fish harvested from the Pacific Ocean are a major contributor to human methylmercury (MeHg) exposure. Limited oceanic mercury (Hg) data, particularly MeHg, has confounded our understanding of linkages between sources, methylation sites, and concentrations in marine food webs. Here we present methylated (MeHg and dimethylmercury (Me2Hg)) and total Hg concentrations from 16 hydrographie stations in the eastern North Pacific Ocean. We use these data in combination with information from previous cruises and coupled atmospheric-oceanic modeling results to better understand controls on Hg concentrations, distribution, and bioavailability. Total Hg concentrations (average 1.14 ?? 0.38 pM) are elevated relative to previous cruises. Modeling results agree with observed increases and suggest that at present atmospheric Hg deposition rates, basin-wide Hg concentrations will double relative to circa 1995 by 2050. Methylated Hg accounts for up to 29% of the total Hg in subsurface waters (average 260 ??114 fM). We observed lower ambient methylated Hg concentrations in the euphotic zone and older, deeper water masses, which likely result from decay of MeHg and Me2Hg when net production is not occurring. We found a significant, positive linear relationship between methylated Hg concentrations and rates of organic carbon remineralization (r2 = 0.66, p < 0.001). These results provide evidence for the importance of particulate organic carbon (POC) transport and remineralization on the production and distribution of methylated Hg species in marine waters. Specifically, settling POC provides a source of inorganic Hg(II) to microbially active subsurface waters and can also provide a substrate for microbial activity facilitating water column methylation. Copyright 2009 by the American Geophysical Union.

  9. Fire in Eastern North American Oak Ecosystems: Filling the Gaps

    Science.gov (United States)

    Julian (Morgan) Varner; Mary Arthur; Stacy Clark; Daniel C. Dey; Justin Hart; Callie Schweitzer

    2016-01-01

    This special issue of Fire Ecology is focused on the fire ecology of eastern USA oak (Quercus L.) forests, woodlands, and savannas. The papers were presented as part of the Fifth Fire in Eastern Oak Forests Conference in Tuscaloosa, Alabama, USA, in 2015. The topic of fire in eastern oak ecosystems is one that has received insufficient interest from the...

  10. Main factors determining bioerosion patterns on rocky cliffs in a drowned valley estuary in the Colombian Pacific (Eastern Tropical Pacific)

    Science.gov (United States)

    Cobo-Viveros, Alba Marina; Cantera-Kintz, Jaime Ricardo

    2015-10-01

    Bioerosion is an important process that destroys coastal rocks in the tropics. However, the rates at which this process occurs, the organisms involved, and the dynamics of rocky cliffs in tropical latitudes have been less studied than in temperate and subtropical latitudes. To contribute to the knowledge of the bioerosion process in rocky cliffs on the Pacific coast of Colombia (Eastern Tropical Pacific) we compared: 1) boring volume, 2) grain size distribution of the rocks, and 3) rock porosity, across three tidal zones of two cliffs with different wave exposure; these factors were related to the bioeroding community found. We observed that cliffs that were not exposed to wave action (IC, internal cliffs) exhibited high percentages of clays in their grain size composition, and a greater porosity (47.62%) and perforation (15.86%) than exposed cliffs (EC, external cliffs). However, IC also exhibited less diversity and abundance of bioeroding species (22 species and 314 individuals, respectively) compared to the values found in EC (41.11%, 14.34%, 32 and 491, respectively). The most abundant bioeroders were Petrolisthes zacae in IC and Pachygrapsus transversus in EC. Our findings show that the tidal zone is the common factor controlling bioerosion on both cliffs; in addition to the abundance of bioeroders on IC and the number of bioeroding species on EC. The integration of geology, sedimentology, and biology allows us to obtain a more comprehensive view of the patterns and trends in the process of bioerosion.

  11. Diversity of culturable filamentous Ascomycetes in the eastern South Pacific Ocean off Chile.

    Science.gov (United States)

    Vera, Jeanett; Gutiérrez, Marcelo H; Palfner, Götz; Pantoja, Silvio

    2017-08-01

    Our study reports the diversity of culturable mycoplankton in the eastern South Pacific Ocean off Chile to contribute with novel knowledge on taxonomy of filamentous fungi isolated from distinct physicochemical and biological marine environments. We characterized spatial distribution of isolates, evaluated their viability and assessed the influence of organic substrate availability on fungal development. Thirty-nine Operational Taxonomic Units were identified from 99 fungal strains isolated from coastal and oceanic waters by using Automatic Barcode Gap Discovery. All Operational Taxonomic Units belonged to phylum Ascomycota and orders Eurotiales, Dothideales, Sordariales and Hypocreales, mainly Penicillium sp. (82%); 11 sequences did not match existing species in GenBank, suggesting occurrence of novel fungal taxa. Our results suggest that fungal communities in the South Pacific Ocean off Chile appear to thrive in a wide range of environmental conditions in the ocean and that substrate availability may be a factor influencing fungal viability in the ocean.

  12. Model Simulation of the Eastern Tropical South Pacific Oxygen Minimum Zone during the Holocene

    Science.gov (United States)

    Schneider, Birgit; Segschneider, Joachim; Xu, Xu; Park, Wonsun; Latif, Mojib

    2016-04-01

    The intensification/expansion of the tropical oxygen minimum zones (OMZs), as observed during the last decades, is usually assigned to anthropogenic climate change. However, natural variability may also affect OMZ variations. To assess the amplitude of natural (millennial-scale) variability in the oxygen minimum zone in the Eastern Tropical South Pacific (ETSP), a global coupled climate-ocean biogeochemical model has been applied to the mid-Holocene (approx. 6 kyrs BP). We find that during the mid-Holocene, the ETSP OMZ may have been better ventilated than today, which is entirely due to ocean circulation effects in the model. The enhanced ventilation is overriding the effect of increased biological production which in large parts of the equatorial Pacific, is driving oxygen towards lower values. The model result is in qualitative agreement with proxy data.

  13. The first report of a microdiverse anammox bacteria community in waters of Colombian Pacific, a transition area between prominent oxygen minimum zones of the eastern tropical Pacific.

    Science.gov (United States)

    Castro-González, M; Molina, V; Rodríguez-Rubio, E; Ulloa, O

    2014-12-01

    Anaerobic ammonium oxidizers contribute to the removal of fixed nitrogen in oxygen-deficient marine ecosystems such as oxygen minimum zones (OMZ). Here we surveyed for the first time the occurrence and diversity of anammox bacteria in the Colombian Pacific, a transition area between the prominent South and North Pacific OMZs. Anammox bacteria were detected in the coastal and oceanic areas of the Colombian Pacific in low oxygen (Pacific, Arabian Sea and Black Sea. Anammox bacteria-like sequences from the Colombian Pacific were grouped together with sequences retrieved from the distinct OMZ's marine subclusters (Peru, Northern Chile and Arabian Sea) within Candidatus ‘Scalindua spp’. Moreover, some anammox bacteria OTUs shared a low similarity with environmental phylotypes (86–94%). Our results indicated that a microdiverse anammox community inhabits the Colombian Pacific, generating new questions about the ecological and biogeochemical differences influencing its community structure.

  14. Circulation, eddies, oxygen and nutrient changes in the eastern tropical South Pacific Ocean

    Directory of Open Access Journals (Sweden)

    R. Czeschel

    2014-09-01

    Full Text Available A large, subsurface oxygen deficiency zone is located in the eastern tropical South Pacific Ocean (ETSP. The large-scale circulation in the eastern equatorial Pacific and off Peru in November/December 2012 shows the influence of the equatorial current system, the eastern boundary currents, and the northern reaches of the subtropical gyre. In November 2012 the Equatorial Undercurrent is centered at 250 m depth, deeper than in earlier observations. In December 2012 the equatorial water is transported southeastward near the shelf in the Peru-Chile Undercurrent with a mean transport of 1.6 Sv. In the oxygen minimum zone (OMZ the flow is overlaid with strong eddy activity on the poleward side of the OMZ. Floats with parking depth at 400 m show fast westward flow in the mid-depth equatorial channel and sluggish flow in the OMZ. Floats with oxygen sensors clearly show the passage of eddies with oxygen anomalies. The long-term float observations in the upper ocean lead to a net community production estimate at about 18° S of up to 16.7 mmol C m−3 yr1 extrapolated to an annual rate and 7.7 mmol C m−3 yr−1 for the time period below the mixed layer. Oxygen differences between repeated ship sections are influenced by the Interdecadal Pacific Oscillation, by the phase of El Niño, by seasonal changes, and by eddies and hence have to be interpreted with care. At and south of the equator the decrease in oxygen in the upper ocean since 1976 is related to an increase in nitrate, phosphate, and in part in silicate.

  15. Oceanographic influences on seabirds and cetaceans of the eastern tropical Pacific: A review

    Science.gov (United States)

    Ballance, Lisa T.; Pitman, Robert L.; Fiedler, Paul C.

    2006-05-01

    This paper is part of a comprehensive review of the oceanography of the eastern tropical Pacific, the oceanic region centered on the eastern Pacific warm pool, but also including the equatorial cold tongue and equatorial current system, and summarizes what is known about oceanographic influences on seabirds and cetaceans there. The eastern tropical Pacific supports on the order of 50 species of seabirds and 30 species of cetaceans as regular residents; these include four endemic species, the world’s largest populations for several others, three endemic sub-species, and a multi-species community that is relatively unique to this ecosystem. Three of the meso-scale physical features of the region are particularly significant to seabirds and cetaceans: the Costa Rica Dome for blue whales and short-beaked common dolphins, the Equatorial Front for planktivorous seabirds, and the countercurrent thermocline ridge for flocking seabirds that associate with mixed-species schools of spotted and spinner dolphins and yellowfin tuna. A few qualitative studies of meso- to macro-scale distribution patterns have indicated that some seabirds and cetaceans have species-specific preferences for surface currents. More common are associations with distinct water masses; these relationships have been quantified for a number of species using several different analytical methods. The mechanisms underlying tropical species-habitat relationships are not well understood, in contrast to a number of higher-latitude systems. This may be due to the fact that physical variables have been used as proxies for prey abundance and distribution in species-habitat research in the eastern tropical Pacific. Though seasonal and interannual patterns tend to be complex, species-habitat relationships appear to remain relatively stable over time, and distribution patterns co-vary with patterns of preferred habitat for a number of species. The interactions between seasonal and interannual variation in

  16. Feeding grounds of the eastern South Pacific humpback whale population include the South Orkney Islands

    OpenAIRE

    Dalla Rosa, Luciano; Félix, Fernando; Stevick, Peter T.; Secchi,Eduardo R; Allen, Judith M; Chater, Kim; Martin, Anthony R.; Basso, Manuela

    2012-01-01

    This paper reports on two photo-identified humpback whales (Megaptera novaeangliae) that were sighted in different years in the proximity of the South Orkney Islands, at the boundary between the Scotia and Weddell seas (60o54.5’S – 46o40.4’W and 60o42.6’S – 45o33’W). One of the whales had been previously sighted off Ecuador, a breeding ground for the eastern South Pacific population. The other whale was subsequently resighted in Bransfield Strait, off the western Antarctic Peninsula, a well-d...

  17. On the Cause of Eastern Equatorial Pacific Ocean T-S Variations Associated with El Nino

    Science.gov (United States)

    Wang, Ou; Fukumori, Ichiro; Lee, Tong; Cheng, Benny

    2004-01-01

    The nature of observed variations in temperature-salinity (T-S) relationship between El Nino and non-El Nino years in the pycnocline of the eastern equatorial Pacific Ocean (NINO3 region, 5(deg)S-5(deg)N, 150(deg)W-90(deg)W) is investigated using an ocean general circulation model. The origin of the subject water mass is identified using the adjoint of a simulated passive tracer. The higher salinity during El Nino is attributed to larger convergence of saltier water from the Southern Hemisphere and smaller convergence of fresher water from the Northern Hemisphere.

  18. Elaphomyces appalachiensis and E. verruculosus sp. nov. (Ascomycota Eurotiales, Elaphomycetaceae) from eastern North America

    Science.gov (United States)

    Michael A. Castellano; Gonzalo Guevara Guerrero; Jesus Garcia Jimenez; James M. Trappe

    2012-01-01

    We describe Elaphomyces verruculosus as new species from eastern North America, ranging from Quebec, Canada south along the eastern USA and along the Gulf Coast to northeastern México. E. verruculosus is similar in overall morphology to E. granulatus of Europe. In addition we re-describe E....

  19. Enhanced warming of the subtropical mode water in the North Pacific and North Atlantic

    Science.gov (United States)

    Sugimoto, Shusaku; Hanawa, Kimio; Watanabe, Tomowo; Suga, Toshio; Xie, Shang-Ping

    2017-09-01

    Over the past six decades, the subtropical surface ocean has warmed at rates close to those of global mean surface ocean temperature except in western boundary current regions where the surface warming is locally enhanced by a factor of two. Changes in the subsurface ocean, however, remain unclear because of lack of data. Compiling historical temperature measurements--some available for the first time--here we show that the subtropical mode water has warmed over the past six decades in both the North Pacific and North Atlantic. The rate of the warming is twice as large in the mode waters than at the surface. Subtropical mode waters are important water masses of vertically uniform temperature that are a few hundred metres thick and distributed widely in the main thermocline of the subtropical oceans. The enhanced warming of subtropical mode waters can be traced back to the surface warming in the formation regions along the western boundary current extensions. Furthermore, we detect increased temperature stratification and decreased dissolved oxygen in the subtropical mode waters. The latter change has clear implications for predicting biogeochemical responses to climate warming.

  20. Drought variability in the eastern Australia and New Zealand summer drought atlas (ANZDA, CE 1500-2012) modulated by the Interdecadal Pacific Oscillation

    Science.gov (United States)

    Palmer, Jonathan G.; Cook, Edward R.; Turney, Chris S. M.; Allen, Kathy; Fenwick, Pavla; Cook, Benjamin I.; O'Donnell, Alison; Lough, Janice; Grierson, Pauline; Baker, Patrick

    2015-12-01

    Agricultural production across eastern Australia and New Zealand is highly vulnerable to drought, but there is a dearth of observational drought information prior to CE 1850. Using a comprehensive network of 176 drought-sensitive tree-ring chronologies and one coral series, we report the first Southern Hemisphere gridded drought atlas extending back to CE 1500. The austral summer (December-February) Palmer drought sensitivity index reconstruction accurately reproduces historically documented drought events associated with the first European settlement of Australia in CE 1788, and the leading principal component explains over 50% of the underlying variance. This leading mode of variability is strongly related to the Interdecadal Pacific Oscillation tripole index (IPO), with a strong and robust antiphase correlation between (1) eastern Australia and the New Zealand North Island and (2) the South Island. Reported positive, negative, and neutral phases of the IPO are consistently reconstructed by the drought atlas although the relationship since CE 1976 appears to have weakened.

  1. Climate impacts on the structures of the North Pacific air-sea CO2 flux variability

    Directory of Open Access Journals (Sweden)

    Y. Nojiri

    2011-05-01

    Full Text Available Some dominant spatial and temporal structures of the North Pacific air-sea CO2 fluxes in response to the Pacific Decadal Oscillation (PDO are identified in four data products from four independent sources: an assimilated CO2 flux product, two forward model solutions, and a gridded pCO2 dataset constructed with a neural network approach. The interannual variability of CO2 flux is found to be an order of magnitude weaker compared to the seasonal cycle of CO2 flux in the North Pacific. A statistical approach is employed to quantify the signal-to-noise ratio in the reconstructed dataset to delineate the representativity errors. The dominant variability with a signal-to-noise ratio above one is identified and its correlations with PDO are examined. A tentative four-box structure in the North Pacific air-sea CO2 flux variability linked to PDO emerges in which two positively correlated boxes are oriented in the northwest and southeast directions and contrarily, the negatively correlated boxes are oriented in the northeast and southwest directions. This pattern is verified with the CO2 and pCO2 from four products and its relations to the interannual El Niño-Southern Oscillation (ENSO and lower-frequency PDO are separately identified. A combined EOF analysis between air-sea CO2 flux and key variables representing ocean-atmosphere interactions is carried out to elicit robust oscillations in the North Pacific CO2 flux in response to the PDO. The proposed spatial and temporal structures of the North Pacific CO2 fluxes are insightful since they separate the secular trends of the surface ocean carbon from the interannual variability. The regional characterization of the North Pacific in terms of PDO and CO2 flux variability is also instructive for determining the homogeneous oceanic domains for the Regional Carbon Cycle and Assessment Processes (RECCAP.

  2. Relationship between the Asian-Pacific oscillation and the tropical cyclone frequency in the western North Pacific

    Institute of Scientific and Technical Information of China (English)

    ZHOU BoTao; CUI Xuan; ZHAO Ping

    2008-01-01

    The relationship between the Asian-Pacific oscillation (APO) and the tropical cyclone frequency over the western North Pacific (WNP) in summer is preliminarily investigated through an analysis of observed data. The result has shown clearly that APO is significantly and positively correlated to the tropical cyclone frequency in the WNP. If APO is above (below) the normal in summer, more (less) tropical cyclones will tend to appear in the WNP. The present study also addresses the large-scale atmospheric general circulation changes underlying the linkage between APO and the WNP tropical cyclone frequency. It follows that a positive phase of summer APO is concurrent with weakened as well as northward and eastward located western Pacific subtropical high (WPSH), low-level convergence and high-level divergence, and reduced vertical zonal wind shear in the WNP, providing favorable environment for the tropical cyclone genesis, and thus more tropical cyclones will come into being, and vice versa.

  3. Relationship between the Asian-Pacific oscillation and the tropical cyclone frequency in the western North Pacific

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The relationship between the Asian-Pacific oscillation (APO) and the tropical cyclone frequency over the western North Pacific (WNP) in summer is preliminarily investigated through an analysis of ob- served data. The result has shown clearly that APO is significantly and positively correlated to the tropical cyclone frequency in the WNP. If APO is above (below) the normal in summer, more (less) tropical cyclones will tend to appear in the WNP. The present study also addresses the large-scale at- mospheric general circulation changes underlying the linkage between APO and the WNP tropical cy- clone frequency. It follows that a positive phase of summer APO is concurrent with weakened as well as northward and eastward located western Pacific subtropical high (WPSH), low-level convergence and high-level divergence, and reduced vertical zonal wind shear in the WNP, providing favorable envi- ronment for the tropical cyclone genesis, and thus more tropical cyclones will come into being, and vice versa.

  4. Climate change in the North Pacific region over the past three centuries

    Science.gov (United States)

    Moore, G. W. K.; Holdsworth, Gerald; Alverson, Keith

    2002-11-01

    The relatively short length of most instrumental climate records restricts the study of climate variability, and it is therefore essential to extend the record into the past with the help of proxy data. Only since the late 1940s have atmospheric data been available that are sufficient in quality and spatial resolution to identify the dominant patterns of climate variability, such as the Pacific North America pattern and the Pacific Decadal Oscillation. Here we present a 301-year snow accumulation record from an ice core at a height of 5,340 m above sea level-from Mount Logan, in northwestern North America. This record shows features that are closely linked with the Pacific North America pattern for the period of instrumental data availability. Our record extends back in time to cover the period from the closing stages of the Little Ice Age to the warmest decade in the past millennium. We find a positive, accelerating trend in snow accumulation after the middle of the nineteenth century. This trend is paralleled by a warming over northwestern North America which has been associated with secular changes in both the Pacific North America pattern and the Pacific Decadal Oscillation.

  5. Modern temperate coral growth analysis in North-west Pacific

    Science.gov (United States)

    Sowa, K.; Watanabe, T.; Sakamoto, T.

    2011-12-01

    Massive coral skeletal growth parameters (skeletal density, extension and calcification rate) are one of the indexes of coral health and ecological response to the ambient environmental changes such as ocean acidification (OA) and global warming. To predict and evaluate the influence of the environment changes to the coral skeletal growth, the coral skeletal growth model (CGM) is one of the useful tools. The CGM is one of the equations consisted of the coral skeletal parameters as response variables and physical or chemical environmental factor such as sea surface temperature (SST), pH, insolation and so on as explanatory variables. The constructing of CGM is equal to the forming the equation and deciding its coefficients. However, there are no universal coral growth models. The aim of our study is to construct the GCM. It is important to analyze coral growth parameters in the past natural condition by using core of massive coral skeleton for our study. In the natural condition, high-latitude area is the best place to evaluate the influence of OA to coral skeletal growth because OA influence ocean organisms from high-latitude area where predicted to affected due to low SST and low carbonate saturation levels induced by dissolved atmospheric CO2 to the sea compared to tropical-subtropical area.This study shows recent temperate coral growth parameters collected from Kagoshima (c.a. 60years), Kochi (c.a. 25 years) and Wakayama (c.a. 30 years) in North-west Pacific, Japan and discusses the universal coral growth model. We quantified the coral growth parameters with uncertainty for the first time. The chronology was developed by δ 18O variant of coral skeletons making sure the forming time of high-low skeletal density area. To evaluate influence of annual SST, precipitation and insolation to coral calcification rate in the natural condition, we performed the regression tree and multiple regression models analysis. As the results, there were non-significances between

  6. Assembly of the eastern North American herpetofauna: new evidence from lizards and frogs

    Science.gov (United States)

    Robert Macey, J; Schulte, James A; Strasburg, Jared L; Brisson, Jennifer A; Larson, Allan; Ananjeva, Natalia B; Wang, Yuezhao; Parham, James F; Papenfuss, Theodore J

    2006-01-01

    Darwin first recognized the importance of episodic intercontinental dispersal in the establishment of worldwide biotic diversity. Faunal exchange across the Bering Land Bridge is a major example of such dispersal. Here, we demonstrate with mitochondrial DNA evidence that three independent dispersal events from Asia to North America are the source for almost all lizard taxa found in continental eastern North America. Two other dispersal events across Beringia account for observed diversity among North American ranid frogs, one of the most species-rich groups of frogs in eastern North America. The contribution of faunal elements from Asia via dispersal across Beringia is a dominant theme in the historical assembly of the eastern North American herpetofauna. PMID:17148411

  7. Shallow Cumulus Variability at the ARM Eastern North Atlantic Site

    Science.gov (United States)

    Lamer, K.; Kollias, P.; Ghate, V. P.; Luke, E. P.

    2016-12-01

    Cumulus clouds play a critical role in modulating the radiative and hydrological budget of the lower troposphere. These clouds, which are ubiquitous in regions of large-scale subsidence over the oceans, tend to be misrepresented in global climate models. Island-based, long-term, high-resolution ground-based observations can provide valuable insights on the factors controlling their macroscopic and microphysical properties and subsequenlty assist in model evaluation and guidance. Previous studies, limited to fair-weather cumuli over land, revealed that their fractional coverage is only weakly correlated with several parameters; the best ones being complex dynamical characteristics of the subcloud layer (vertical velocity skewness and eddy coherence). Other studies noted a relationship between cumuli depth and their propensity to precipitate. The current study will expand on such analysis by performing detail characterization of the full spectrum of shallow cumulus fields from non-precipitating to precipitating in the context of the large-scale forcing (i.e. thermodynamic structure and subsidence rates). Two years of ground-based remote sensing observations collected at the Atmospheric Radiation Measurement (ARM) Eastern North Atlantic (ENA) site are used to document macroscopic (cloud depth, cord length, cover), microphysical (liquid water path, cloud base rain rate) and dynamical (cloud base mass flux, eddy dissipation rate) cumuli properties. The observed variability in shallow cumulus is examined in relation to the variability of the large-scale environment as captured by the humidity profile, the magnitude of the low-level horizontal winds and near-surface aerosol conditions.

  8. Heavy metals exposures among Mexican farmworkers in eastern North Carolina

    Energy Technology Data Exchange (ETDEWEB)

    Quandt, Sara A., E-mail: squandt@wfubmc.edu [Department of Epidemiology and Prevention, Division of Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, NC 27157 (United States); Jones, Bradley T. [Department of Chemistry, Wake Forest University, Winston-Salem, NC (United States); Talton, Jennifer W. [Department of Biostatistical Sciences, Division of Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, NC (United States); Whalley, Lara E. [Department of Family and Community Medicine, Wake Forest University School of Medicine, Winston-Salem, NC (United States); Galvan, Leonardo [North Carolina Farmworkers Project, Benson, NC (United States); Vallejos, Quirina M.; Grzywacz, Joseph G. [Department of Family and Community Medicine, Wake Forest University School of Medicine, Winston-Salem, NC (United States); Chen, Haiying [Department of Biostatistical Sciences, Division of Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, NC (United States); Pharr, Kathryn E. [Department of Chemistry, Wake Forest University, Winston-Salem, NC (United States); Isom, Scott [Department of Biostatistical Sciences, Division of Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, NC (United States); Arcury, Thomas A. [Department of Family and Community Medicine, Wake Forest University School of Medicine, Winston-Salem, NC (United States)

    2010-01-15

    Background: Immigrant farmworkers are a population at risk for numerous environmental and occupational exposures. The metals arsenic, lead, mercury, and cadmium are known neurotoxins to which workers can be exposed both in the US and in their country of origin. Because farmworkers are exposed to neurotoxic pesticides, they may be at risk for adverse health effects from the combined exposure. Objectives: To examine the relationship between exposure to metals, as measured in urine, with personal and work-related characteristics of Mexican migrant and seasonal farmworkers in the US. Methods: We analyzed data on metals found in urine of 258 farmworkers recruited from 44 camps in eastern North Carolina in 2007. Geometric means and 95% confidence intervals (CI) were used to compare data with data from the National Health and Nutrition Examination Survey (NHANES). We used multivariate regression models fitted for each metal to estimate the association of creatinine-corrected urinary metals and worker characteristics related to environmental and occupational exposures. Results: Geometric mean urinary metals concentrations ({mu}g/g creatinine) exceeded NHANES reference values for arsenic (13.23 [CI 11.11, 15.35] vs. 8.55 [CI 7.23, 9.86]) and lead (1.26 [CI 1.08, 1.43] vs. 0.63 [CI 0.60, 0.66]). Age, being from the central region of Mexico, and pack years of cigarette smoking were significant predictors of metals exposure; being a current smoker and years worked in US agriculture were not. Conclusions: This first study to examine indicators of worker body burdens of metals shows that workers have body burdens related to exposures other than work in the US. Further research should address their risk for adverse health outcomes due to combined exposures to neurotoxins in pesticides.

  9. 75 FR 20566 - North Pacific Fishery Management Council; Public Meeting

    Science.gov (United States)

    2010-04-20

    ... to people with disabilities. Requests for sign language interpretation or other auxiliary aids should... models to be considered for inclusion in the GOA and BSAI Pacific cod assessments. DATES:...

  10. 77 FR 67633 - North Pacific Fishery Management Council; Public Meetings

    Science.gov (United States)

    2012-11-13

    ... (including Aleutian Island Risk Assessment) United State Fish & Wildlife (USFWL) Report International Pacific... restrictions; discussion paper on retention of 4A halibut in sablefish pots. 5. Steller Sea Lion...

  11. Paleoclimate. Synchronization of North Pacific and Greenland climates preceded abrupt deglacial warming.

    Science.gov (United States)

    Praetorius, Summer K; Mix, Alan C

    2014-07-25

    Some proposed mechanisms for transmission of major climate change events between the North Pacific and North Atlantic predict opposing patterns of variations; others suggest synchronization. Resolving this conflict has implications for regulation of poleward heat transport and global climate change. New multidecadal-resolution foraminiferal oxygen isotope records from the Gulf of Alaska (GOA) reveal sudden shifts between intervals of synchroneity and asynchroneity with the North Greenland Ice Core Project (NGRIP) δ(18)O record over the past 18,000 years. Synchronization of these regions occurred 15,500 to 11,000 years ago, just prior to and throughout the most abrupt climate transitions of the last 20,000 years, suggesting that dynamic coupling of North Pacific and North Atlantic climates may lead to critical transitions in Earth's climate system.

  12. Fragile Reefs of the Eastern Pacific: Does low Cementation Provide a Model for Reefs in a High CO2 World?

    Science.gov (United States)

    Manzello, D.; Kleypas, J.; Eakin, M.; Budd, D.

    2007-05-01

    Around the world, reefs will experience high pCO2, low pH, low carbonate concentrations, and low aragonite saturation state as atmospheric CO2 rises. Ocean carbon chemistry measurements show that eastern Pacific waters already exist at high pCO2 and low carbonate concentrations due to natural upwelling in the region. Because of the upwelling, this region may serve as a model for coral reef development under enhanced atmospheric CO2 and oceanic pCO2; that is, low coral growth, low secondary cementation, and high physical, chemical, and biological erosion. Reefs in the eastern Pacific Ocean are characterized by low biological diversity and relatively small size. Both past coring and recent analysis reveal that, while many reefs in the eastern Pacific are several thousand years old, they are fragile and lack significant cementation, even in the innermost, oldest structures. They are also extremely porous with high water throughflow. Without secondary cementation, branching coral frameworks are held together only by organically produced calcium carbonate (e.g. coralline algae), sponges, and other reef infauna, and contain a high proportion of loose sediments. The result is reef frameworks that are more susceptible to destruction from mechanical or biological erosion. The poorly cemented nature of eastern Pacific reefs is thus hypothesized to have been a factor in the severe bioerosion that occurred on these reefs after past bleaching events (1982-3, 1997-8). We will present data that indicate low rates of cementation and high rates of erosion on eastern Pacific coral reefs and will compare current carbonate chemistry in the eastern Pacific to model predictions of what reefs around the globe may experience in coming decades.

  13. Phylogeography of the salmonid fish, Dolly Varden Salvelinus malma: multiple glacial refugia in the North Pacific Rim.

    Science.gov (United States)

    Yamamoto, Shoichiro; Maekawa, Koji; Morita, Kentaro; Crane, Penelope A; Oleinik, Alla G

    2014-10-01

    The geographic distribution pattern of mitochondrial DNA (control region) sequence polymorphisms from 73 populations of a salmonid fish, Dolly Varden Salvelinus malma, over most of its range in the North Pacific rim, was examined to assess how its spatial population genetic structure has been molded. The observed 68 haplotypes were grouped into three main lineages, which correspond to western, central, and eastern regions in the North Pacific. The two outlier-haplotype groups gave close agreement with DNA types from two congeneric species, white-spotted charr S. leucomaenis and Arctic charr S. alpinus, respectively. These results suggest that the present-day genetic structure of S. malma reflects historical patterns of isolation and re-colonization, and also historical hybridization with co-distributed species. We also placed the haplotypes of S. malma within our study areas into a pre-existing evolutionary relationship of S. alpinus and S. malma throughout the Northern Hemisphere. Phylogenetic analysis revealed that the Western Lineage S. malma was basal to all other lineages of S. malma and S. alpinus. Our data serve as a biogeographic hypothesis for salmonid fishes that the Sea of Japan and/or Sea of Okhotsk regions represents a place of origin for S. malma and S. alpinus groups currently distributed in circumpolar regions.

  14. The Diet Composition of Beaked Whales and Melon-Headed Whales from the North Pacific

    Science.gov (United States)

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. The Diet Composition of Beaked Whales and Melon-Headed... Whales from the North Pacific Kristi West College of Natural and Computational Science Hawaii Pacific University 45-045 Kamehameha Hwy...contents of stranded animals are rarely available. Very little information on food habits of most species of beaked whales or of melon-headed whales

  15. Siderophore-based microbial adaptations to iron scarcity across the eastern Pacific Ocean

    Science.gov (United States)

    Boiteau, Rene M.; Mende, Daniel R.; Hawco, Nicholas J.; McIlvin, Matthew R.; Fitzsimmons, Jessica N.; Saito, Mak A.; Sedwick, Peter N.; DeLong, Edward F.; Repeta, Daniel J.

    2016-12-01

    Nearly all iron dissolved in the ocean is complexed by strong organic ligands of unknown composition. The effect of ligand composition on microbial iron acquisition is poorly understood, but amendment experiments using model ligands show they can facilitate or impede iron uptake depending on their identity. Here we show that siderophores, organic compounds synthesized by microbes to facilitate iron uptake, are a dynamic component of the marine ligand pool in the eastern tropical Pacific Ocean. Siderophore concentrations in iron-deficient waters averaged 9 pM, up to fivefold higher than in iron-rich coastal and nutrient-depleted oligotrophic waters, and were dominated by amphibactins, amphiphilic siderophores with cell membrane affinity. Phylogenetic analysis of amphibactin biosynthetic genes suggests that the ability to produce amphibactins has transferred horizontally across multiple Gammaproteobacteria, potentially driven by pressures to compete for iron. In coastal and oligotrophic regions of the eastern Pacific Ocean, amphibactins were replaced with lower concentrations (1–2 pM) of hydrophilic ferrioxamine siderophores. Our results suggest that organic ligand composition changes across the surface ocean in response to environmental pressures. Hydrophilic siderophores are predominantly found across regions of the ocean where iron is not expected to be the limiting nutrient for the microbial community at large. However, in regions with intense competition for iron, some microbes optimize iron acquisition by producing siderophores that minimize diffusive losses to the environment. These siderophores affect iron bioavailability and thus may be an important component of the marine iron cycle.

  16. Homoplasious colony morphology and mito-nuclear phylogenetic discordance among Eastern Pacific octocorals.

    Science.gov (United States)

    Ament-Velásquez, Sandra L; Breedy, Odalisca; Cortés, Jorge; Guzman, Hector M; Wörheide, Gert; Vargas, Sergio

    2016-05-01

    Octocorals are a diverse and ecologically important group of cnidarians. However, the phylogenetic relationships of many octocoral groups are not well understood and are based mostly on mitochondrial sequence data. In addition, the discovery and description of new gorgonian species displaying unusual or intermediate morphologies and uncertain phylogenetic affinities further complicates the study of octocoral systematics and raises questions about the role played by processes such as plasticity, crypsis, and convergence in the evolution of this group of organisms. Here, we use nuclear (i.e. 28S rDNA) and mitochondrial (mtMutS) markers and a sample of Eastern Pacific gorgonians thought to be remarkable from a morphological point of view to shed light on the morphological diversification among these organisms. Our study reveals the loss of the anastomosed colony morphology in two unrelated lineages of the seafan genus Pacifigorgia and offers strong evidence for the independent evolution of a whip-like morphology in two lineages of Eastern Pacific Leptogorgia. Additionally, our data revealed one instance of mito-nuclear discordance in the genera Leptogorgia and Eugorgia, which may be the results of incomplete lineage sorting or ancient hybridization-introgression events. Our study stresses the importance of comprehensive taxonomic sampling and the use of independent sources of evidence to address the phylogenetic relationships and clarifying the evolution of octocorals.

  17. Characterization of mesoscale convective systems over the eastern Pacific during boreal summer

    Science.gov (United States)

    Berthet, Sarah; Rouquié, Bastien; Roca, Rémy

    2015-04-01

    The eastern Pacific Ocean is one of the most active tropical disturbances formation regions on earth. This preliminary study is part of a broader project that aims to investigate how mesoscale convective systems (MCS) may be related to these synoptic disturbances with emphasis on local initiation of tropical depressions. As a first step, the main characteristics of the MCS over the eastern Pacific are documented with the help of the recently developed TOOCAN tracking algorithm (Fiolleau and Roca, 2013) applied to the infrared satellite imagery data from GOES-W and -E for the period JJAS 2012-2014. More specifically, the spatial distribution of the MCS population, the statistics of their spatial extensions and durations, as well as their trajectories and propagation speeds are summarized. In addition the environment of the MCS will be investigated using various Global Precipitation Mission datasets and the Megha-Tropiques/SAPHIR humidity microwave sounder derived products. Reference: Fiolleau T. and R. Roca, (2013), An Algorithm For The Detection And Tracking Of Tropical Mesoscale Convective Systems Using Infrared Images From Geostationary Satellite, Transactions on Geoscience and Remote Sensing, doi: 10.1109/TGRS.2012.2227762.

  18. Constraining recent lead pollution sources in the North Pacific using ice core stable lead isotopes

    Science.gov (United States)

    Gross, B. H.; Kreutz, K. J.; Osterberg, E. C.; McConnell, J. R.; Handley, M.; Wake, C. P.; Yalcin, K.

    2012-08-01

    Trends and sources of lead (Pb) aerosol pollution in the North Pacific rim of North America from 1850 to 2001 are investigated using a high-resolution (subannual to annual) ice core record recovered from Eclipse Icefield (3017 masl; St. Elias Mountains, Canada). Beginning in the early 1940s, increasing Pb concentration at Eclipse Icefield occurs coevally with anthropogenic Pb deposition in central Greenland, suggesting that North American Pb pollution may have been in part or wholly responsible in both regions. Isotopic ratios (208Pb/207Pb and 206Pb/207Pb) from 1970 to 2001 confirm that a portion of the Pb deposited at Eclipse Icefield is anthropogenic, and that it represents a variable mixture of East Asian (Chinese and Japanese) emissions transported eastward across the Pacific Ocean and a North American component resulting from transient meridional atmospheric flow. Based on comparison with source material Pb isotope ratios, Chinese and North American coal combustion have likely been the primary sources of Eclipse Icefield Pb over the 1970-2001 time period. The Eclipse Icefield Pb isotope composition also implies that the North Pacific mid-troposphere is not directly impacted by transpolar atmospheric flow from Europe. Annually averaged Pb concentrations in the Eclipse Icefield ice core record show no long-term trend during 1970-2001; however, increasing208Pb/207Pb and decreasing 206Pb/207Pb ratios reflect the progressive East Asian industrialization and increase in Asian pollutant outflow. The post-1970 decrease in North American Pb emissions is likely necessary to explain the Eclipse Icefield Pb concentration time series. When compared with low (lichen) and high (Mt. Logan ice core) elevation Pb data, the Eclipse ice core record suggests a gradual increase in pollutant deposition and stronger trans-Pacific Asian contribution with rising elevation in the mountains of the North Pacific rim.

  19. Relationship between real meridional volume transport and Sverdrup transport in the North Subtropical Pacific

    Institute of Scientific and Technical Information of China (English)

    JIANG Hua; WANG Hui; ZHU Jiang; TAN Benkui

    2006-01-01

    The oceanic meridional volume transport (MVT) in the North Subtropical Pacific is calculated directly from an observed velocity field (real MVT) and indirectly from wind stress based on Sverdrup balance, respectively. It is confirmed that the Sverdrup MVT is a good approximation to the real MVT for the North Subtropical Pacific except in the western boundary region, where the difference is expected because of frictional and nonlinear effects.The time evolution of the MVT derived from a revised Sverdrup balance, in which a time delay due to the propagation of the first baroclinic Rossby wave is considered, is well correlated with that of the real MVT on decadal time scale, especially near the western boundary region. It is suggested that the Sverdrup balance can be used to study not only the mean climatology of the oceanic circulation, but also the time-dependent oceanic circulation of the North Subtropical Pacific when the Rossby wave propagation is taken into account.

  20. Description of two new associated infaunal decapod crustaceans (Axianassidae and Alpheidae from the tropical eastern Pacific

    Directory of Open Access Journals (Sweden)

    Arthur Anker

    2015-08-01

    Full Text Available Two new species of infaunal decapod crustaceans are described based on material collected in Bahía Málaga, Pacific coast of Colombia, in 2009. The mud-shrimp Axianassa darrylfelderi sp. nov. (Axianassidae appears to be most closely related to A. australis Rodrigues & Shimizu, 1992, A. canalis Kensley & Heard, 1990, and A. jamaicensis Kensley & Heard, 1990. The new species may be distinguished from each of them by a combination of morphological features, mainly on the uropodal exopod, antennal acicle, third maxilliped and first pleonite. The shrimp Leptalpheus canterakintzi sp. nov. (Alpheidae, associated with burrows of A. darrylfelderi sp. nov., undoubtedly represents the eastern Pacific sister species of the western Atlantic L. axianassae Dworschak & Coelho, 1999, which lives exclusively in burrows of A. australis. The two species are reliably distinguishable only by the proportions of the merus and propodus of the third pereiopod. Leptalpheus azuero Anker, 2011, previously known only from the Pacific coast of Panama, is reported for the first time from Bahía Málaga, Colombia.

  1. Aeolian contamination of Se and Ag in the North Pacific from Asian fossil fuel combustion.

    Science.gov (United States)

    Ranville, Mara A; Cutter, Gregory A; Buck, Clifton S; Landing, William M; Cutter, Lynda S; Resing, Joseph A; Flegal, A Russell

    2010-03-01

    Energy production from fossil fuels, and in particular the burning of coal in China, creates atmospheric contamination that is transported across the remote North Pacific with prevailing westerly winds. In recent years this pollution from within Asia has increased dramatically, as a consequence of vigorous economic growth and corresponding energy consumption. During the fourth Intergovernmental Oceanographic Commission baseline contaminant survey in the western Pacific Ocean from May to June, 2002, surface waters and aerosol samples were measured to investigate whether atmospheric deposition of trace elements to the surface North Pacific was altering trace element biogeochemical cycling. Results show a presumably anthropogenic enrichment of Ag and of Se, which is a known tracer of coal combustion, in the North Pacific atmosphere and surface waters. Additionally, a strong correlation was seen between dissolved Ag and Se concentrations in surface waters. This suggests that Ag should now also be considered a geochemical tracer for coal combustion, and provides further evidence that Ag exhibits a disturbed biogeochemical cycle as the result of atmospheric deposition to the North Pacific.

  2. Large bio-geographical shifts in the north-eastern Atlantic Ocean

    DEFF Research Database (Denmark)

    Hátún, Hjálmar; Payne, Mark; Beaugrand, G.

    2009-01-01

    and persistent bottom-up bio-physical link is demonstrated using a numerical ocean general circulation model and data on four trophically connected levels in the food chain – phytoplankton, zooplankton, blue whiting, and pilot whales. The plankton data give a unique basin-scale depiction of these changes...... water masses in the north-eastern North Atlantic Ocean, associated with changes in the strength and extent of the subpolar gyre. These exchanges lead to variations in the influence exerted by the subarctic or Lusitanian biomes on the intermediate faunistic zone in the north-eastern Atlantic. This strong...

  3. North Pacific Mesoscale Coupled Air-Ocean Simulations Compared with Observations

    Energy Technology Data Exchange (ETDEWEB)

    Cerovecki, Ivana [Univ. of California, San Diego, CA (United States). Scripps Inst. of Oceanography; McClean, Julie [Univ. of California, San Diego, CA (United States). Scripps Inst. of Oceanography; Koracin, Darko [Desert Research Inst. (DRI), Reno, NV (United States). Division of Atmospheric Sciences

    2014-11-14

    The overall objective of this study was to improve the representation of regional ocean circulation in the North Pacific by using high resolution atmospheric forcing that accurately represents mesoscale processes in ocean-atmosphere regional (North Pacific) model configuration. The goal was to assess the importance of accurate representation of mesoscale processes in the atmosphere and the ocean on large scale circulation. This is an important question, as mesoscale processes in the atmosphere which are resolved by the high resolution mesoscale atmospheric models such as Weather Research and Forecasting (WRF), are absent in commonly used atmospheric forcing such as CORE forcing, employed in e.g. the Community Climate System Model (CCSM).

  4. Developments in Ground-Motion Modeling in Eastern North America

    Science.gov (United States)

    Atkinson, G. M.; Boore, D. M.

    2012-12-01

    Recent well-recorded earthquakes in Eastern North America (ENA) have led us to re-evaluate concepts that have been "standard fare" in the development of ground-motion prediction equations (GMPEs) for ENA for decades, including all published GMPEs that are used in current practice (e.g. Atkinson and Boore, 2011, 2006, 1995; Pezeshk et al., 2011; Campbell, 2003; Toro et al., 1997, etc.). Assumptions common to all ENA GMPEs that may not be true include the following. (1) Typical ENA stress drops, in the context of a Brune model representation of the source spectrum, are in the range of 150-300 bars, with the exception of occasional high-stress events like the 1988 Saguenay earthquake. (2) Attenuation of ground motions can be modeled with a frequency-independent geometric spreading function, either bilinear or trilinear in shape (e.g. Street and Turcotte, 1975; Herrmann and Kijko, 1983; Atkinson and Mereu, 1992; Atkinson, 2004; Boatwright and Seekins, 2011), and an associated frequency-dependent anelastic attenuation term related to the regional Quality factor. The use of a bilinear or trilinear form models the transition from geometric spreading of body waves at close distances to slower surface-wave-type spreading at regional distances. We use ground-motion recordings from recent ENA events to re-examine these basic tenets of GMPE development, in light of constraints on the problem provided at low frequencies by seismic moment, and at high frequencies by stresses inferred from Empirical Greens Function (EGF) analysis. We find strong evidence, in both ground-motion data and from the constraints, that geometric attenuation may be frequency dependent. Moreover, EGF stress drops may be very high (>500 bars) - but they do not lead to particularly large high-frequency ground motions, at least at distances for which we have observations. More complex models of ENA source and attenuation processes appear to be required in order to reconcile our growing ground-motion database

  5. A description of the tides in the Eastern North Atlantic

    Science.gov (United States)

    Fanjul, Enrique Alvarez; Gómez, Begoña Pérez; Sánchez-Arévalo, Ignacio Rodríguez

    A description of the Eastern North Atlantic tidal dynamics (in a region spanning from 20°N to 48°N in latitude and from 34°W to 0° in longitude) is obtained by means of new in situ measurements and numerical modelling based on TOPEX/POSEIDON-derived data sets. The main source of measurements is the tide gauge network REDMAR (RED de MAReógrafos de Puertos del Estado), operative since July 1992 and managed by Clima Marítimo (Puertos del Estado). Results derived from the harmonic analysis of the first years of measurements are presented and compared with model results. In order to obtain a global picture of the tides in the region, a large compilation of harmonic constants obtained from other institutes is included. The availability of new TOPEX/POSEIDON-derived harmonic constants data sets provides a chance to include the benefits derived from satellite altimetry in high resolution regional applications of numerical models. Richard Ray's tidal model (Ray et al., 1994), based on a response type tidal analysis of TOPEX/POSEIDON data, was employed within a model of the studied area. The numerical model employed is HAMSOM, a 3-D finite difference code developed both by the Institut für Meereskunde (Hamburg University) and Clima Marítimo. Results from simulations of seven major harmonics are presented, providing a comprehensive view of tidal dynamics, including current information. The results of tidal simulations show good agreement between semidiurnal harmonic components and the values measured by both coastal and pelagic tidal gauges and by current meters. The modelled diurnal constituents show larger relative differences with measurements than semidiurnal harmonics, especially concerning the phase lags. The non-linear transfer of energy from semidiurnal to higher order harmonics, such as M 4 and M 6, was mapped. Those transfers were found to be important only in two areas: the French continental shelf in the Bay of Biscay and the widest part of the African

  6. Surface constraints on the temporal and spatial evolution of the Farallon-Pacific-North America plate boundary

    Science.gov (United States)

    McQuarrie, N.; Oskin, M.

    2009-05-01

    Extension and volcanism are two surface derived data sets used to infer mantle processes back in time. We integrate two new large GIS-based datasets to create palinspastic restorations of extension and volcanism allowing us to readdress the relationship between plate-boundary deformation, intra-plate extension and magmatism in western North America. Using ArcGIS and custom software, we retrodeformed the NAVDat (North American Volcanic Database, navdat.geongrid.org) using the western North America reconstruction of McQuarrie and Wernicke (2005). We compare this data to strain rates calculated over a 50 km-grid forward- deformed from 36 Ma to present. With the deformed grid and palinspastically restored volcanic dataset we quantitatively compare rates of magmatism and deformation and evaluate the age, location, and migration of Cenozoic volcanic arcs. A first order conclusion from this study is that magmatism, throughout the Basin and Range, is primarily driven by plate boundary effects. The plate boundary effects include subduction and rollback of the Farallon plate, creation and expansion of slab windows as the Pacific plate intercepts the North American plate and re-establishment of the ancestral Cascade arc along the eastern margin of the Sierra Nevada at ˜ 15 Ma. Notable exceptions include the Yellowstone hotspot system along the northern boarder of our study area and late-stage (<8 Ma) passive, extension related asthenospheric upwelling that accompanied a thinning lithosphere along the eastern and western margins of the Basin and Range. The palinspastic reconstructions presented here highlight that the classic, high-angle, Basin and Range faulting that comprises most of the physiographic Basin and Range province commenced during a remarkably amagmatic period. These observations largely contradicts the active rifting model where magmatism triggers Basin and Range extension

  7. Sediment budget for Rediu reservoir catchment, North-Eastern Romania

    Science.gov (United States)

    Todosi, Cristian; Niculita, Mihai

    2016-04-01

    Sediment budgets are a useful tool for geomorphologic analysis, catchment management and environmental assessment, despite the uncertainties related to their assessment. We present the sediment budget construction and validation for a small catchment of 9.5319 kmp (953.19 ha) situated in the North-Eastern part of Romania. The Rediu reservoir was built between 1986 and 1988, on Rediu valley, a left tributary of Bahlui river, north-west from Iasi city. The catchment of the reservoir has 6.5 km in length and 2.5 km in maximum width, the altitudes decreasing from 170 m in the northern part, to 52 m in the southern part. The valley is symmetric, the altitude of the hillslopes going between 200 m to 75 m in one km length, in the transversal section with the maximum width. The floodplain is narrow having between 20 m to 210 m (in the area of confluence with Breazu tributary). The mean slope of the catchment is 6.4 degree, the maximum slope being 24.6 degrees. The length of channels which show banks of up to 2 m is 19.98 km. The land is used predominantly as crops (58.1 %), 16.7 % being covered by pastures (from which over half are eroded), 11.5 % percent of the catchment being covered by planted forests, 9.2 % by rural constructions and roads, 2.9 % by hayfields, 1.5 % by lakes and 0.1 % by orchards. Beside the Rediu reservoir, there are three ponds (15 771, 1761 and 751 sqm) in the catchment. We considered the trap efficiency for the reservoir and the ponds to be 95%. Aerial images from 1963, 1978 , 1984, 2005, 2008, 2010, 2012 and 2014 were used to assess the state of geomorphological processes before and after the reservoir construction. After 1970 a gully system situated in Breazu tributary sub-catchment and several active landslides along the main valley left side were forested. Beside these processes, soil erosion and human impact by constructions are the main processes generating sediment in the study area. The sediment yields were quantified by estimating the

  8. Comparative phylogeography of the wild-rice genus Zizania (Poaceae) in eastern Asia and North America.

    Science.gov (United States)

    Xu, Xin-Wei; Wu, Jin-Wei; Qi, Mei-Xia; Lu, Qi-Xiang; Lee, Peter F; Lutz, Sue; Ge, Song; Wen, Jun

    2015-02-01

    Comparative phylogeography of intercontinental disjunct taxa allowed us not only to elucidate their diversification and evolution following geographic isolation, but also to understand the effect of climatic and geological histories on the evolutionary processes of closely related species. A phylogeographic analysis was conducted on the eastern Asian-North American disjunct genus Zizania to compare intracontinental phylogeographic patterns between different continents. Surveys were conducted of 514 individuals using three chloroplast DNA fragments and three nuclear microsatellite loci. These individuals included 246 from 45 populations of Zizania latifolia in eastern Asia, and the following from North America: 154 individuals from 26 populations of Z. aquatica, 84 individuals from 14 populations of Z. palustris, and 30 individuals from one population of Z. texana. The genetic diversity of North American Zizania was significantly higher than that of eastern Asian Zizania. High levels of genetic differentiation among populations and no signal of population expansion were detected in three widespread species. No phylogeographic structure was observed in Z. latifolia, and discordant patterns of cpDNA and microsatellite markers were observed in North American Zizania. Reduced variation in Zizania latifolia likely reflects its perennial life history, the North American origin of Zizania, and the relative homogeneity of aquatic environments. High levels of genetic differentiation suggest limited dispersal among populations in all Zizania species. The more complex patterns of diversification and evolution in North American Zizania may be driven by the greater impact of glaciation in North America relative to eastern Asia. © 2015 Botanical Society of America, Inc.

  9. Population genetics of an ecosystem-defining reef coral Pocillopora damicornis in the Tropical Eastern Pacific.

    Directory of Open Access Journals (Sweden)

    David J Combosch

    Full Text Available BACKGROUND: Coral reefs in the Tropical Eastern Pacific (TEP are amongst the most peripheral and geographically isolated in the world. This isolation has shaped the biology of TEP organisms and lead to the formation of numerous endemic species. For example, the coral Pocillopora damicornis is a minor reef-builder elsewhere in the Indo-West Pacific, but is the dominant reef-building coral in the TEP, where it forms large, mono-specific stands, covering many hectares of reef. Moreover, TEP P. damicornis reproduces by broadcast spawning, while it broods mostly parthenogenetic larvae throughout the rest of the Indo-West Pacific. Population genetic surveys for P. damicornis from across its Indo-Pacific range indicate that gene flow (i.e. larval dispersal is generally limited over hundreds of kilometers or less. Little is known about the population genetic structure and the dispersal potential of P. damicornis in the TEP. METHODOLOGY: Using multilocus microsatellite data, we analyzed the population structure of TEP P. damicornis among and within nine reefs and test for significant genetic structure across three geographically and ecologically distinct regions in Panama. PRINCIPAL FINDINGS/CONCLUSIONS: We detected significant levels of population genetic structure (global R(ST = 0.162, indicating restricted gene flow (i.e. larvae dispersal, both among the three regions (R(RT = 0.081 as well as within regions (R(SR = 0.089. Limited gene flow across a distinct environmental cline, like the regional upwelling gradient in Panama, indicates a significant potential for differential adaptation and population differentiation. Individual reefs were characterized by unexpectedly high genet diversity (avg. 94%, relatively high inbreeding coefficients (global F(IS = 0.183, and localized spatial genetic structure among individuals (i.e. unique genets over 10 m intervals. These findings suggest that gene flow is limited in TEP P. damicornis

  10. 75 FR 27989 - North Pacific Fishery Management Council; Public Meetings

    Science.gov (United States)

    2010-05-19

    ... and fishery overlap; review Pacific cod assessment model run proposals (SSC only); review Council... - initial/final action. 10. Staff Tasking: Review Committees and tasking. 11. Other Business The SSC agenda... Sustainable Fisheries, National Marine Fisheries Service. BILLING CODE 3510-22-S...

  11. The relative importance of tropical variability forced from the North Pacific through ocean pathways

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, Amy; Shin, Sang-Ik [NOAA/Earth System Research Laboratory, Physical Sciences Division, Boulder, CO (United States); CIRES Climate Diagnostics Center, Boulder, CO (United States); Alexander, Michael A. [NOAA/Earth System Research Laboratory, Physical Sciences Division, Boulder, CO (United States); McCreary, Julian P. [University of Hawaii, International Pacific Research Center, Honolulu, HI (United States)

    2008-08-15

    To what extent is tropical variability forced from the North Pacific through ocean pathways relative to locally generated variability and variability forced through the atmosphere? To address this question, in this study we use an anomaly-coupled model, consisting of a global, atmospheric general circulation model and a 41/2-layer, reduced-gravity, Pacific-Ocean model. Three solutions are obtained; with coupling over the entire basin (CNT), with coupling confined to the tropics and wind stress and heat fluxes in the North and South Pacific specified by climatology (TP), and with coupling confined to the Tropics and wind stress and heat fluxes in the North Pacific specified by output from CNT (NPF). It is found that there are two distinct signals forced in the North Pacific that can impact the tropics through ocean pathways. These two signals are forced by wind stress and surface heat flux anomalies in the subtropical North Pacific. The first signal is relatively fast, impacts tropical variability less than a year after forcing, is triggered from November to March, and propagates as a first-mode baroclinic Rossby wave. The second signal is only triggered during springtime when buoyancy forcing can effectively generate higher-order baroclinic modes through subduction anomalies into the permanent thermocline, and it reaches the equator 4-5 years after forcing. The slow signal is found to initiate tropical variability more efficiently than the fast signal with one standard deviation in subtropical zonal wind stress forcing tropical SST anomalies centered on the equator at 135 W of approximately 0.5 C. Allowing extratropically forced tropical variability is found to shift primarily 2-year ENSO variability in a tropics-alone simulation to a more realistic range of 2-6 years. (orig.)

  12. The relative importance of tropical variability forced from the North Pacific through ocean pathways

    Science.gov (United States)

    Solomon, Amy; Shin, Sang-Ik; Alexander, Michael A.; McCreary, Julian P.

    2008-08-01

    To what extent is tropical variability forced from the North Pacific through ocean pathways relative to locally generated variability and variability forced through the atmosphere? To address this question, in this study we use an anomaly-coupled model, consisting of a global, atmospheric general circulation model and a 4½-layer, reduced-gravity, Pacific-Ocean model. Three solutions are obtained; with coupling over the entire basin (CNT), with coupling confined to the tropics and wind stress and heat fluxes in the North and South Pacific specified by climatology (TP), and with coupling confined to the Tropics and wind stress and heat fluxes in the North Pacific specified by output from CNT (NPF). It is found that there are two distinct signals forced in the North Pacific that can impact the tropics through ocean pathways. These two signals are forced by wind stress and surface heat flux anomalies in the subtropical North Pacific. The first signal is relatively fast, impacts tropical variability less than a year after forcing, is triggered from November to March, and propagates as a first-mode baroclinic Rossby wave. The second signal is only triggered during springtime when buoyancy forcing can effectively generate higher-order baroclinic modes through subduction anomalies into the permanent thermocline, and it reaches the equator 4-5 years after forcing. The slow signal is found to initiate tropical variability more efficiently than the fast signal with one standard deviation in subtropical zonal wind stress forcing tropical SST anomalies centered on the equator at 135°W of approximately 0.5°C. Allowing extratropically forced tropical variability is found to shift primarily 2-year ENSO variability in a tropics-alone simulation to a more realistic range of 2-6 years.

  13. Climatological analysis of passage-type tropical cyclones from the Western North Pacific into the South China Sea

    Directory of Open Access Journals (Sweden)

    Jau-Ming Chen

    2017-01-01

    Full Text Available Tropical cyclone (TC climatological characteristics with passage from the Western North Pacific (WNP into the South China Sea (SCS during the June - November season are analyzed in this study. These TCs tend to form in the WNP west of 150°E, and on average westward by 7 - 12° in longitude than TCs that do not track into the SCS. Their formation locations migrate with the monsoon trough, moving northward from June to August, and southward from September to November. The probability of a WNP TC moving into the SCS varies seasonally, with only 12 - 18% of the WNP TCs doing so during August-September due to more northern TC formation. However, this probability rises to 25 - 26% in June - July and 25 - 32% in October - November with more southern TC formation. The passage-type TCs generally form in the eastern part of an elongated lower-level cyclonic anomaly of the 10-day low-pass filtered environmental circulation in the 10 - 20°N zone, which is paired with an anticyclonic anomaly to the north. Between this circulation pair, anomalous easterly flows steer these TCs westward, giving them a westward track into the SCS. The formation of these passage-type TCs is associated with a southward displacement of the monsoon trough and a westward intensification of the Pacific subtropical high in August and September. During June - July (October - November, the associated features appear as a southeastward (meridional expansion of the monsoon trough and a northward displacement of the Pacific subtropical high.

  14. Estimate of radiocaesium derived FNPP1 accident in the North Pacific Ocean

    Science.gov (United States)

    Inomata, Yayoi; Aoyama, Michio; Tsubono, Takaki; Tsumune, Daisuke; Yamada, Masatoshi

    2017-04-01

    134Cs and 137Cs (radiocaesium) were released to the North Pacific Ocean by direct discharge and atmospheric deposition released from the TEPCO Fukushima Dai-ichi Nuclear Power Plant (FNPP1) accident in 2011. After the FNPP1 accident, measurements of 134Cs and 137Cs were conducted by many researches. However, those results are only snapshots in order to interpret the distribution and transport of the released radiocaesium on a basin scale. It is recognized that estimation of the total amount of released 134Cs and 137Cs is necessary to assess the radioecological impacts of their release on the environment. It was reported that the inventory of 134Cs or 137Cs on the North Pacific Ocean after the FNPP1 accident was 15.2-18.3 PBq based on the observations (Aoyama et al., 2016a), 15.3±1.6 PBq by OI analysis (Inomata et al., 2016), 16.1±1.64 PBq by global ocean model (Tsubono et al., 2016). These suggest that more than 75 % of the atmospheric-released radiocaesium (15.2-20.4 PBq; Aoyama et al., 2016a) were deposited on the North Pacific Ocean. The radiocaesium from the atmospheric fallout and direct discharge were expected to mixing as well as diluting near the coastal region and transported eastward across the North Pacific Ocean in the surface layer. Furthermore, radicaesium were rapidly mixed and penetrated into the subsurface water in the North Pacific Ocean in winter. It was revealed that these radiocaesium existed in the Subtropical Mode Water (STMW, Aoyama et al., 2016b; Kaeriyama et al., 2016) and Central Mode Water (CMW, Aoyama et al., 2016b), suggesting that mode water formation and subduction are efficient pathway for the transport of FNPP1 derived radiocaesium into the ocean interior within 1-year timescale. Kaeriyama et al. (2016) estimated the total amount of FNPP1 derived radiocaesium in the STMW was 4.2 ± 1.1 PBq in October-November 2012. However, there is no estimation of the amount of radiocaesium in the CMW. Therefore, it is impossible to discuss

  15. A geochemical comparison of alkalic lavas in the Trans-Mexican Volcanic Belt, peninsular Baja California and intraplate volcanoes in the eastern Pacific

    Science.gov (United States)

    Tian, L.; Castillo, P. R.

    2011-12-01

    The Trans-Mexican Volcanic Belt (TMVB) is a continental volcanic arc built along the southern edge of the North American plate. The volcanic rocks along TMVB are compositionally diverse and the origin of its alkalic lavas with ocean island basalt (OIB)-like composition is highly controversial. Alkalic lavas from four regions in the western, central, and eastern TMVB [e.g., Verma and Hasenaka, Geochem. J., 58, 2004; Petrone et al., Geol. S. Am. S., 402, 2006; Orozco-Esquivel et al., Geol. Soc. Amer. Bull., 93, 2007] are compared with similar OIB-like alkalic lavas from peninsular Baja California [e.g., Storey et al., Terra Nova, 1, 1989; Castillo, Geol. Soc. Amer. Bull., 120, 2008] and intraplate volcanoes in the eastern Pacific [Tian et al., Geochem. Geophys. Geosyst., 12, 2011] in order to ascertain their geochemical similarities and differences and to constrain the compositions of their respective magma sources. A few of the alkalic lavas from TMVB have very similar trace element and isotopic compositions as the OIB-like alkalic lavas from peninsular Baja California and intraplate volcanoes in the eastern Pacific. Majority of the TMVB alkalic lavas, however, are compositionally more heterogeneous, similar to the less-alkalic Nb-enriched basalts in peninsular Baja California representing OIB-like alkalic lavas that had been contaminated by other mantle components and/or crustal materials. Thus, data seem to indicate that all the OIB-like alkalic lavas can be traced to a similar source, the compositionally heterogeneous Pacific asthenosphere.

  16. Impacts of Potential Aircraft Observations on Forecasts of Tropical Cyclones Over the Western North Pacific

    Science.gov (United States)

    2014-12-01

    OBSERVATIONS ON FORECASTS OF TROPICAL CYCLONES OVER THE WESTERN NORTH PACIFIC by Mark C. Mitchell December 2014 Thesis Co-Advisors: Patrick A. Harr...COVERED Master’s Thesis 4. TITLE AND SUBTITLE IMPACTS OF POTENTIAL AIRCRAFT OBSERVATIONS ON FORECASTS OF TROPICAL CYCLONES OVER THE WESTERN NORTH...of the storm inner core. 14. SUBJECT TERMS Global Hawk, Tropical Cyclone Reconnaissance, Observations, Data Assimilation, Numerical Weather

  17. Spatial and temporal variability in nutrients and carbon uptake during 2004 and 2005 in the eastern equatorial Pacific Ocean

    DEFF Research Database (Denmark)

    Palacz, A. P.; Chai, F.

    2012-01-01

    The eastern equatorial Pacific plays a great role in the global carbon budget due to its enhanced biological productivity linked to the equatorial upwelling. However, as confirmed by the Equatorial Biocomplexity cruises in 2004 and 2005, nutrient upwelling supply varies strongly, partly due to th...

  18. Phylogeny and Biogeography of Thuja L. (Cupressaceae), an Eastern Asian and North American Disjunct Genus

    Institute of Scientific and Technical Information of China (English)

    Jian-Hua LI; Qiao-Ping XIANG

    2005-01-01

    In order to develop better insights into biogeographic patterns of eastern Asian and North American disjunct plant genera, sequences of nuclear ribosomal DNA internal transcribed spacer (nr DNA ITS) region were used to estimate interspecific relationships of Thuja L. (Cupressaceae) and infer its biogeography based on the phylogeny. According to the phylogenetic analysis, two clades were recognized. The first clade included Thuja plicata D. Don (western North America) and T. koraiensis Nakai (northeastern Asia), and the second one contained T. occidentalis (Gord.) Carr. (Japan). The ancestral area of Thuja was inferred to be eastern Asia, and two dispersal events were responsible for the modern distribution of Thuja in North America. Both the North Atlantic land bridge and Bering land bridge were possible routes for the migration of ancestral populations to North America.

  19. Neogene dinocyst zonation for the eastern North Sea Basin, Denmark

    DEFF Research Database (Denmark)

    Dybkjær, Karen; Piasecki, Stefan

    2010-01-01

    - and sequence stratigraphy. The dinocyst zonation and the foraminifer zonation of the Danish Miocene (based upon analysis of the same boreholes) were independently calibrated with the established nannoplankton zonation. This correlation revealed a mismatch generally corresponding to one nannoplankton zone...... for the Achomosphaera andalousiensis Zone. Neogene biostratigraphy in the North Sea Basin has been problematic due to the periodically limited connection between the North Sea Basin and the North Atlantic Ocean, especially with respect to stratigraphy based on foraminifers and calcareous nannoplankton. Many...

  20. Regionality and seasonality of submesoscale and mesoscale turbulence in the North Pacific Ocean

    Science.gov (United States)

    Sasaki, Hideharu; Klein, Patrice; Sasai, Yoshikazu; Qiu, Bo

    2017-09-01

    The kinetic energy (KE) seasonality has been revealed by satellite altimeters in many oceanic regions. Question about the mechanisms that trigger this seasonality is still challenging. We address this question through the comparison of two numerical simulations. The first one, with a 1/10° horizontal grid spacing, 54 vertical levels, represents dynamics of physical scales larger than 50 km. The second one, with a 1/30° grid spacing, 100 vertical levels, takes into account the dynamics of physical scales down to 16 km. Comparison clearly emphasizes in the whole North Pacific Ocean, not only a significant KE increase by a factor up to three, but also the emergence of seasonal variability when the scale range 16-50 km (called submesoscales in this study) is taken into account. But the mechanisms explaining these KE changes display strong regional contrasts. In high KE regions, such the Kuroshio Extension and the western and eastern subtropics, frontal mixed-layer instabilities appear to be the main mechanism for the emergence of submesoscales in winter. Subsequent inverse kinetic energy cascade leads to the KE seasonality of larger scales. In other regions, in particular in subarctic regions, results suggest that the KE seasonality is principally produced by larger-scale instabilities with typical scales of 100 km and not so much by smaller-scale mixed-layer instabilities. Using arguments from geostrophic turbulence, the submesoscale impact in these regions is assumed to strengthen mesoscale eddies that become more coherent and not quickly dissipated, leading to a KE increase.

  1. Quality Control Methodology Of A Surface Wind Observational Database In North Eastern North America

    Science.gov (United States)

    Lucio-Eceiza, Etor E.; Fidel González-Rouco, J.; Navarro, Jorge; Conte, Jorge; Beltrami, Hugo

    2016-04-01

    This work summarizes the design and application of a Quality Control (QC) procedure for an observational surface wind database located in North Eastern North America. The database consists of 526 sites (486 land stations and 40 buoys) with varying resolutions of hourly, 3 hourly and 6 hourly data, compiled from three different source institutions with uneven measurement units and changing measuring procedures, instrumentation and heights. The records span from 1953 to 2010. The QC process is composed of different phases focused either on problems related with the providing source institutions or measurement errors. The first phases deal with problems often related with data recording and management: (1) compilation stage dealing with the detection of typographical errors, decoding problems, site displacements and unification of institutional practices; (2) detection of erroneous data sequence duplications within a station or among different ones; (3) detection of errors related with physically unrealistic data measurements. The last phases are focused on instrumental errors: (4) problems related with low variability, placing particular emphasis on the detection of unrealistic low wind speed records with the help of regional references; (5) high variability related erroneous records; (6) standardization of wind speed record biases due to changing measurement heights, detection of wind speed biases on week to monthly timescales, and homogenization of wind direction records. As a result, around 1.7% of wind speed records and 0.4% of wind direction records have been deleted, making a combined total of 1.9% of removed records. Additionally, around 15.9% wind speed records and 2.4% of wind direction data have been also corrected.

  2. The first reported ceratopsid dinosaur from eastern North America (Owl Creek Formation, Upper Cretaceous, Mississippi, USA

    Directory of Open Access Journals (Sweden)

    Andrew A. Farke

    2017-05-01

    Full Text Available Ceratopsids (“horned dinosaurs” are known from western North America and Asia, a distribution reflecting an inferred subaerial link between the two landmasses during the Late Cretaceous. However, this clade was previously unknown from eastern North America, presumably due to limited outcrop of the appropriate age and depositional environment as well as the separation of eastern and western North America by the Western Interior Seaway during much of the Late Cretaceous. A dentary tooth from the Owl Creek Formation (late Maastrichtian of Union County, Mississippi, represents the first reported occurrence of Ceratopsidae from eastern North America. This tooth shows a combination of features typical of Ceratopsidae, including a double root and a prominent, blade-like carina. Based on the age of the fossil, we hypothesize that it is consistent with a dispersal of ceratopsids into eastern North America during the very latest Cretaceous, presumably after the two halves of North America were reunited following the retreat of the Western Interior Seaway.

  3. Interdecadal component variation characteristics in heavy winter snow intensity in North-Eastern China and its response to sea surface temperatures

    Science.gov (United States)

    Zhao, Chun-Yu; Fang, Yi-He; Luo, Yong; Wang, Ji

    2016-11-01

    Based on daily precipitation data from 208 weather stations, monthly NCEP/NCAR reanalysis data, and sea surface temperature data reconstructed by NOAA between 1961 and 2012, the heavy winter snow intensity in North-Eastern China was defined; its spatiotemporal variation characteristics were analyzed; the physical mechanisms of the relations between key sea surface temperature (SST) regions and heavy winter snow intensity were studied. Results showed that, in terms of temporal variation characteristics: heavy winter snow intensity in North-Eastern China has been rising, with obvious interdecadal variations during the study interval. In terms of spatial variation characteristics: the first empirical orthogonal function (EOF) mode of the interdecadal component in heavy winter snow intensity showed consistent anomaly characteristics throughout the region; the second mode exhibited opposite variation characteristics between the south and north; and the third mode exhibited opposite variation characteristics between the northwest and southeast. In terms of physical mechanisms underlying the effects of SST on heavy winter snow intensity, the key SST region of the first EOF mode was the Oyashio, the interdecadal component of the autumn Oyashio SST was abnormally high, which corresponded to a higher winter 500 hPa height field in the northern section of the North Pacific. This condition led to a blocking situation and was associated with a weaker East Asian winter monsoon (EAMW), which resulted in a stronger interdecadal component of heavy winter snow intensity and vice versa. The second mode was closely related to the Pacific Decadal Oscillation (PDO): the interdecadal component of the autumn PDO was abnormal, which induced the teleconnection pattern of the winter Pacific-North America (PNA) pattern. The PNA pattern may have been related to the second EOF mode through its association with the Mongolian high.

  4. North Pacific Meridional Mode over the Common Era

    Science.gov (United States)

    Sanchez, S. C.; Charles, C. D.; Amaya, D. J.; Miller, A. J.

    2016-12-01

    The Pacific Meridional Mode (PMM) has been increasingly recognized as an influential mode of variability for channeling extratropical anomalies to the equatorial ocean-atmosphere system. The PMM has been identified as an important precursor for ENSO, a source of much decadal power in the tropical Pacific, and is potentially intensifying. It is still unknown why the Pacific Meridional Mode might be intensifying; most arguments center around the changing mean state associated with anthropogenic global warming. There are a number of processes by which the background state could influence the PMM: altering the location of trade winds, the characteristics of stochastic forcing, the sensitivity of latent heat flux to surface wind anomalies, the wind response to SST anomalies, or changing the Intertropical Convergence Zone (ITCZ) structure. Recent work has found that the PMM is particularly sensitive to ITCZ shifts in intensity and location (using a simple linear coupled model, [Martinez-Villalobos and Vimont 2016]). Over the last millennium the ITCZ has experienced epochs of notable latitudinal shifts to balance the cross equatorial energy transport. Here we investigate how the strength of the PMM may have varied with these shifts in the ITCZ over the Common Era using the CESM-Last Millennium Ensemble (LME). We assess the strength of the PMM pathway by the degree of air-sea coupling and the amplitude of tropical decadal variability. We expect the ITCZ location and the degree of air-sea coupling (WES feedback) to play a critical role in determining the effectiveness and intensity of the PMM pathway. We verify our inferences in the LME with coral paleoproxy records from the central tropical Pacific. Chiefly we target records from the Line Islands (spanning 1°N to 6°N) to infer variations in the location of the ITCZ and the amplitude of decadal variability. This work enables us to discuss the idea of an intensifying PMM in a more historical context.

  5. Atmospheric response to the North Pacific enabled by daily sea surface temperature variability

    Science.gov (United States)

    Zhou, Guidi; Latif, Mojib; Greatbatch, Richard J.; Park, Wonsun

    2015-09-01

    Ocean-atmosphere interactions play a key role in climate variability on a wide range of timescales from seasonal to decadal and longer. The extratropical oceans are thought to exert noticeable feedbacks on the atmosphere especially on decadal and longer timescales, yet the large-scale atmospheric response to anomalous extratropical sea surface temperature (SST) is still under debate. Here we show, by means of dedicated high-resolution atmospheric model experiments, that sufficient daily variability in the extratropical background SST needs to be resolved to force a statistically significant large-scale atmospheric response to decadal North Pacific SST anomalies associated with the Pacific Decadal Oscillation, which is consistent with observations. The large-scale response is mediated by atmospheric eddies. This implies that daily extratropical SST fluctuations must be simulated by the ocean components and resolved by the atmospheric components of global climate models to enable realistic simulation of decadal North Pacific sector climate variability.

  6. Relationships between the North Pacific Oscillation and the typhoon/hurricane frequencies

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Relationships between the North Pacific Oscillation (NPO) and the typhoon as well as hurricane frequencies are documented. The correlation between NPO index in June-July-August-September and the annual typhoon number in the western North Pacific is 0.37 for the period of 1949―1998. The NPO is correlated with the annual hurricane number in the tropical Atlantic at - 0.28 for the same period. The variability of NPO is found to be concurrent with the changes of the magnitude of vertical zonal wind shear, sea-level pressure patterns, as well as the sea surface temperature, which are physically associated with the typhoons and hurricanes genesis. The NPO associated atmospheric circulation variability is analyzed to explain how NPO is linked with variability of the tropical atmospheric circulation in the western Pacific and the tropical Atlantic, via the atmospheric teleconnection.

  7. Ice core record of rising lead pollution in the North Pacific atmosphere

    Science.gov (United States)

    Osterberg, E.; Mayewski, P.; Kreutz, K.; Fisher, D.; Handley, M.; Sneed, S.; Zdanowicz, C.; Zheng, J.; Demuth, M.; Waskiewicz, M.; Bourgeois, J.

    2008-03-01

    A high-resolution, 8000 year-long ice core record from the Mt. Logan summit plateau (5300 m asl) reveals the initiation of trans-Pacific lead (Pb) pollution by ca. 1730, and a >10-fold increase in Pb concentration (1981-1998 mean = 68.9 ng/l) above natural background (5.6 ng/l) attributed to rising anthropogenic Pb emissions from Asia. The largest rise in North Pacific Pb pollution from 1970-1998 (end of record) is contemporaneous with a decrease in Eurasian and North American Pb pollution as documented in ice core records from Greenland, Devon Island, and the European Alps. The distinct Pb pollution history in the North Pacific is interpreted to result from the later industrialization and less stringent abatement measures in Asia compared to North America and Eurasia. The Mt. Logan record shows evidence for both a rising Pb emissions signal from Asia and a trans-Pacific transport efficiency signal related to the strength of the Aleutian Low.

  8. Climate Change Impacts to North Pacific Pelagic Habitat Are Projected to Lower Carrying Capacity

    Science.gov (United States)

    Woodworth-Jefcoats, P. A.; Polovina, J. J.; Drazen, J.

    2016-02-01

    We use output from a suite of CMIP5 earth system models to explore the impacts of climate change on marine fisheries over the 21st century. Ocean temperatures from both the historical and RCP 8.5 projections are integrated over the upper 200 m of the water column to characterize thermal habitat in the epipelagic realm. We find that across all models the projected temperature increases lead to a redistribution of thermal habitat: temperatures that currently represent the majority of North Pacific pelagic habitat are replaced by temperatures several degrees warmer. Additionally, all models project the emergence of new thermal habitat that exceeds present-day maximum temperatures. Spatially, present-day thermal habitat retreats northward and contracts eastward as warmer habitat in the southern and western North Pacific expands. In addition to these changes in thermal habitat, zooplankton densities are projected to decline across much of the North Pacific. Taken together, warming temperatures and declining zooplankton densities create the potential for mismatches in metabolic demand and supply through the 21st century. We find that carrying capacity for tropical tunas and other commercially valuable pelagic fish may be especially vulnerable to the impacts of climate change. The waters projected to see the greatest redistribution of thermal habitat and greatest declines in zooplankton densities are primarily those targeted by the Hawaii-based and international longline fleets. Fishery managers around the North Pacific will need to incorporate these impacts of climate change into future management strategies.

  9. Atlas of Nonindigenous Marine and Estuarine Species in the North Pacific

    Science.gov (United States)

    The product consists of a report synthesizing available information on nonindigenous species in the North Pacific. We note that while this product focuses on invasive species, the tools and approaches developed for this research are the precursors on how we will address identifyi...

  10. Carbon cycling in the Arctic Archipelago: the export of Pacific carbon to the North Atlantic

    Directory of Open Access Journals (Sweden)

    E. H. Shadwick

    2009-01-01

    Full Text Available The Arctic Ocean is expected to be disproportionately sensitive to climatic changes, and is thought to be an area where such changes might be detected. The Arctic hydrological cycle is influenced by: runoff and precipitation, sea ice formation/melting, and the inflow of saline waters from Bering and Fram Straits and the Barents Sea Shelf. Pacific water is recognizable as intermediate salinity water, with high concentrations of dissolved inorganic carbon (DIC, flowing from the Arctic Ocean to the North Atlantic via the Canadian Arctic Archipelago. We present DIC data from an east-west section through the Archipelago, as part of the Canadian International Polar Year initiatives. The fractions of Pacific and Arctic Ocean waters leaving the Archipelago and entering Baffin Bay, and subsequently the North Atlantic, are computed. The eastward transport of carbon from the Pacific, via the Arctic, to the North Atlantic is estimated.

    Altered mixing ratios of Pacific and freshwater in the Arctic Ocean have been recorded in recent decades. Any climatically driven alterations in the composition of waters leaving the Arctic Archipelago may have implications for anthropogenic CO2 uptake, and hence ocean acidification, in the subpolar and temperate North Atlantic.

  11. Carbon Cycling in the Arctic Archipelago: The Export of Pacific Carbon to the North Atlantic

    Science.gov (United States)

    Shadwick, E. H.; Papakyriakou, T.; Prowe, A. E. F.; Leong, D.; Moore, S.; Thomas, H.

    2009-04-01

    The Arctic Ocean is expected to be disproportionately sensitive to climatic changes, and thought to be an area where such changes might be detected. The Arctic hydrological cycle is influenced by: runoff and precipitation, sea ice formation/melting, and the inflow of saline waters from Bering and Fram Straits and the Barents Sea Shelf. Pacific water is recognizable as low salinity water, with high concentrations of dissolved inorganic carbon (DIC), flowing from the Arctic Ocean to the North Atlantic via the Canadian Arctic Archipelago. We present DIC data from an east-west section through the Archipelago, as part of the Canadian International Polar Year initiatives. The fractions of Pacific and Arctic Ocean waters leaving the Archipelago and entering Baffin Bay, and subsequently the North Atlantic, are computed. The eastward transport of carbon from the Pacific, via the Arctic, to the North Atlantic is estimated. Altered mixing ratios of Pacific and freshwater in the Arctic Ocean have been recorded in recent decades. Any climatically driven alterations in the composition of waters leaving the Arctic Archipelago may have implications for anthropogenic CO2 uptake, and hence ocean acidification, in the subpolar and temperate North Atlantic.

  12. New genera and species of antipatharian corals (Cnidaria: Anthozoa) from the North Pacific

    NARCIS (Netherlands)

    Opresko, D.M.

    2005-01-01

    New taxa of deep water antipatharian corals of the North Pacific are described. Represented in the family Schizopathidae are: Bathypathes seculata spec. nov.; Umbellapathes gen. nov.; U. helioanthes spec. nov.; U. bipinnata spec. nov.; Dendrobathypathes boutillieri spec. nov.; D. fragilis spec. nov.

  13. Changes in tussock architecture of invasive Spartina densiflora (Poaceae) along the Pacific Coast of North America

    Science.gov (United States)

    It is important to link functional trait-based responses of invaders to environmental changes to improve our understanding of mechanisms that promote invasiveness. The invasion of alien Spartina densiflora Brongn. along the Pacific coast of North America provides a natural model system for studying ...

  14. A database of paleoceanographic sediment cores from the North Pacific, 1951–2016

    Directory of Open Access Journals (Sweden)

    M. Borreggine

    2017-09-01

    Full Text Available We assessed sediment coring, data acquisition, and publications from the North Pacific (north of 30° N from 1951 to 2016. There are 2134 sediment cores collected by American, French, Japanese, Russian, and international research vessels across the North Pacific (including the Pacific subarctic gyre, Alaskan gyre, Japan margin, and California margin; 1391 cores, the Sea of Okhotsk (271 cores, the Bering Sea (123 cores, and the Sea of Japan (349 cores reported here. All existing metadata associated with these sediment cores are documented here, including coring date, location, core number, cruise number, water depth, vessel metadata, and coring technology. North Pacific sediment core age models are built with isotope stratigraphy, radiocarbon dating, magnetostratigraphy, biostratigraphy, tephrochronology, % opal, color, and lithological proxies. Here, we evaluate the iterative generation of each published age model and provide comprehensive documentation of the dating techniques used, along with sedimentation rates and age ranges. We categorized cores according to the availability of a variety of proxy evidence, including biological (e.g., benthic and planktonic foraminifera assemblages, geochemical (e.g., major trace element concentrations, isotopic (e.g., bulk sediment nitrogen, oxygen, and carbon isotopes, and stratigraphic (e.g., preserved laminations proxies. This database is a unique resource to the paleoceanographic and paleoclimate communities and provides cohesive accessibility to sedimentary sequences, age model development, and proxies. The data set is publicly available through PANGAEA at https://doi.org/10.1594/PANGAEA.875998.

  15. Dust transport from non-East Asian sources to the North Pacific

    Science.gov (United States)

    Hsu, S.; Huh, C.; Lin, C.; Chen, W.; Mahowald, N. M.; Liu, S. C.; Chou, C. C.; Liang, M.; Tsai, C.; Lin, F.; Chen, J.; Huang, Y.

    2012-12-01

    It is generally thought that East Asia dominates the supply of eolian dust to the North Pacific. Here we show the first data-based evidence of dust primarily from non-East Asian sources even during March 2010 when a super dust storm from East Asia struck the western Pacific. Chemical characteristics of aerosol samples collected at a high-mountain site in Taiwan show variable inputs from eolian dust and biomass burning. From backward trajectory analyses, satellite observation and model simulation, dust origins can be traced to the Middle East and North Africa, suggesting an integrated source from the global dust belt. Our global model results demonstrate that dust deposition in the North Pacific is primarily contributed by non-East Asian sources with an eastward decrease along the Westerlies. Time-series of aerosol composition at Mt. Lulin: (A) 210Pb and biomass burning potassium (KBB), (B) 7Be and aluminum. Also shown (in A) are daily mean O3 and CO , hourly relative humidity (gray curve/area) and (in B) daily rainfall (yellow bars) measured at Taiwan EPA's Lulin Atmospheric Background Station (LABS), ~25 m southeast of our aerosol sampling site. Results from the MATCH model showing (A) total annual dust deposition fluxes, and (B) fraction of the total deposition attributable to East Asian sources over the North Pacific.

  16.  Climate change may trigger broad shifts in North America's Pacific Coastal rainforests

    Science.gov (United States)

    Dominick A. DellaSala; Patric Brandt; Marni   Koopman; Jessica Leonard; Claude Meisch; Patrick Herzog; Paul Alaback; Michael I. Goldstein; Sarah Jovan; Andy MacKinnon; Henrik von Wehrden

    2015-01-01

    Climate change poses significant threats to Pacific coastal rainforests of North America. Land managers currently lack a coordinated climate change adaptation approach with which to prepare the region's globally outstanding biodiversity for accelerating change. We provided analyses intended to inform coordinated adaptation for eight focal rainforest tree species...

  17. Geochemistry of eastern North American CAMP diabase dykes

    Science.gov (United States)

    Callegaro, S.; Marzoli, A.; Bertrand, H.; Reisberg, L. C.; Chiaradia, M.; Bellieni, G.

    2011-12-01

    The Piedmont area of the Appalachians and the coastal plains of eastern North America (ENA) were intruded between 202 and 195 Ma[1,2] by swarms of diabase (dolerite) dykes and a few sills of the Central Atlantic magmatic province (CAMP). Different trends are observed for the dykes, from NW (more frequent in the South), to N-S and NE, thus a radial pattern and a coeval emplacement driven by the bulging effect of a mantle plume were initially inferred[3]. Conversely, based on field data, an age progression can be defined from NW- to N- and NE-oriented dykes, supporting a diachronous northward rift-to-drift transition during Pangaea break-up. New geochemical data on 74 ENA dykes suggest a dominant lithospheric mantle source for these magmatic suite. A deep enriched mantle source is further discarded by the crystallization temperatures (ca.1350°C) calculated[4] for high-Fo (up to Fo89) olivines, which do not reflect very hot (i.e. mantle-plume) potential mantle temperatures. Incompatible trace element contents are fairly homogeneous and generally low, e.g. (La/Yb)Ch (0.54-2.39), typical of melts derived from a quite depleted shallow (spinel) mantle-source. However, isotopic compositions of ENA dykes display a considerable spread in initial isotopic signatures, do not show correlation with incompatible trace elements, and are independent of the orientation and age of the dykes, i.e. 87Sr/86Sr200Ma (0.7043-0.7088), ɛNd200Ma (-6.67-+2.42) and 206Pb/204Pb200Ma (17.46-18.61). Pb isotopic compositions plot above the NHRL, at positive Δ7/4 (10-17) and Δ8/4 (19-73), calling for an enriched ancient component in the mantle source. Unradiogenic 187Os/188Os200Ma ratios (0.127-0.144) argue for negligible amounts of crustal contamination and, coupled with the large range of Sr-Nd-Pb isotopic compositions, suggest generation from a strongly heterogeneous mantle source, probably metasomatized lithosphere. Lithospheric mantle underlying the Appalachian orogen may have undergone

  18. Characteristics of the Nonoccurrence of Tropical Cyclones in the Western North Pacific in August 2014

    Directory of Open Access Journals (Sweden)

    Jae-Won Choi

    2016-10-01

    Full Text Available This study identified the causes of the nonoccurrence of tropical cyclones (TCs in August 2014 by examining large-scale environments. First, over the previous 30 years, the TC genesis frequency in August showed an overall statistically significant decline. In the tropical and subtropical western Pacific, the outgoing longwave radiation anomaly index also exhibited an overall increase until recently. Regarding precipitable water and precipitation, an analysis was performed on the difference between the mean values for August 2014 and the mean values for August over the previous 30 years. As a result, while convective activities were suppressed in the tropical and subtropical western Pacific, convective activities were strong in the mid-latitudes of East Asia. This indicates that while the western North Pacific summer monsoon was weakened in August 2014, the East Asian summer monsoon was strengthened. The weakening of the western North Pacific summer monsoon may have made it difficult for TCs to occur. An analysis of 850 hPa and 500 hPa stream flows showed the strengthening of anomalous huge anticyclonic circulations in the tropical and subtropical western Pacific, whereas anomalously cyclonic circulations were reinforced in the mid-latitudes of East Asia. This was associated with the result that the western North Pacific subtropical high (WNPSH showed further westward and southward expansion in August 2014 compared to the climatological mean WNPSH. Therefore, TCs were unlikely to occur in the tropical and subtropical western Pacific, but anomalous cold northerlies and anomalous warm southerlies converged in the Japanese Islands after originating in China’s central region and passing the East China Sea. Therefore, a favorable environment for the occurrence of precipitation had been formed.

  19. NUMERICAL MODELING STUDY OF EFFECTS OF EASTERN PACIFIC WARM POOL ON ENSO

    Institute of Scientific and Technical Information of China (English)

    YUE Cai-jun; LU Wei-song; Xiaofan LI

    2010-01-01

    In this study,sensitivity experiments were conducted with the Zebiak-Cane ocean-atmosphere coupled model forced by the wind stress anomaly from the U.S.National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data to study the impacts of eastern Pacific warm pool on the formation and development of ENSO events.The effects of climatological mean sea surface temperature of the warm pool on forecast skill during the ENSO events of 1982-1999 are more considerable that those of climatological mean meridional winds and ocean currents.The forecast skill for the 1997/1998 E1 Ni(n)o event is characterized by sensitivity to climatological mean sea surface temperature and anomalies of northerly winds and currents.The forecast skill is found insensitive to climatological mean northerly meridional winds and currents.

  20. Non-destructive γ spectrum analysis of polymetallic nodules from the eastern Pacific

    Institute of Scientific and Technical Information of China (English)

    刘广山; 黄奕普; 蔡毅华; 陈敏

    2002-01-01

    -- Non-destructive γ spectrum analyses of 20 polymetallic nodules from the eastern Pacific were carried out. Numerous nuclides, such as 238 U, 230 Th, 226 Ra, 210 Pb, 228 Ra, 228 Th, 235 U, 227 Ac ( or 231pa) and 40K were detected. The count rates of the nuclides in the top or bottom side of nodules facing detector were measured and the ratio R of the count rates of nuclides in the top and the bottom sides was obtained. From counts and ratios, some useful information relating to the growth and movement of the nodules, the source of nuclide and relationship between those and environment can be gotten. A new method for clear distinction between the top and bottom sides of the nodule based on the R value of 226Ra or 210pb was developed. In addition, one can infer the turnover of nodules according to the R value of 230Th.

  1. Environmental drivers of mesozooplankton biomass variability in the North Pacific Subtropical Gyre

    Science.gov (United States)

    Valencia, Bellineth; Landry, Michael R.; Décima, Moira; Hannides, Cecelia C. S.

    2016-12-01

    The environmental drivers of zooplankton variability are poorly explored for the central subtropical Pacific, where a direct bottom-up food-web connection is suggested by increasing trends in primary production and mesozooplankton biomass at station ALOHA (A Long-term Oligotrophic Habitat Assessment) over the past 20 years (1994-2013). Here we use generalized additive models (GAMs) to investigate how these trends relate to the major modes of North Pacific climate variability. A GAM based on monthly mean data explains 43% of the temporal variability in mesozooplankton biomass with significant influences from primary productivity (PP), sea surface temperature (SST), North Pacific Gyre Oscillation (NPGO), and El Niño. This result mainly reflects the seasonal plankton cycle at station ALOHA, in which increasing light and SST lead to enhanced nitrogen fixation, productivity, and zooplankton biomass during summertime. Based on annual mean data, GAMs for two variables suggest that PP and 3-4 year lagged NPGO individually account for 40% of zooplankton variability. The full annual mean GAM explains 70% of variability of zooplankton biomass with significant influences from PP, 4 year lagged NPGO, and 4 year lagged Pacific Decadal Oscillation (PDO). The NPGO affects wind stress, sea surface height, and subtropical gyre circulation and has been linked to mideuphotic zone anomalies in salinity and PP at station ALOHA. Our study broadens the known impact of this climate mode on plankton dynamics in the North Pacific. While lagged transport effects are also evident for subtropical waters, our study highlights a strong coupling between zooplankton fluctuations and PP, which differs from the transport-dominated climate influences that have been found for North Pacific boundary currents.

  2. Eccentricity pacing of eastern equatorial Pacific carbonate dissolution cycles during the Miocene Climatic Optimum

    Science.gov (United States)

    Kochhann, Karlos G. D.; Holbourn, Ann; Kuhnt, Wolfgang; Channell, James E. T.; Lyle, Mitch; Shackford, Julia K.; Wilkens, Roy H.; Andersen, Nils

    2016-09-01

    The Miocene Climatic Optimum (MCO; ~16.9 to 14.7 Ma) provides an outstanding opportunity to investigate climate-carbon cycle dynamics during a geologically recent interval of global warmth. We present benthic stable oxygen (δ18O) and carbon (δ13C) isotope records (5-12 kyr time resolution) spanning the late early to middle Miocene interval (18 to 13 Ma) at Integrated Ocean Drilling Program (IODP) Site U1335 (eastern equatorial Pacific Ocean). The U1335 stable isotope series track the onset and development of the MCO as well as the transitional climatic phase culminating with global cooling and expansion of the East Antarctic Ice Sheet at ~13.8 Ma. We integrate these new data with published stable isotope, geomagnetic polarity, and X-ray fluorescence (XRF) scanner-derived carbonate records from IODP Sites U1335, U1336, U1337, and U1338 on a consistent, astronomically tuned timescale. Benthic isotope and XRF scanner-derived CaCO3 records depict prominent 100 kyr variability with 400 kyr cyclicity additionally imprinted on δ13C and CaCO3 records, pointing to a tight coupling between the marine carbon cycle and climate variations. Our intersite comparison further indicates that the lysocline behaved in highly dynamic manner throughout the MCO, with >75% carbonate loss occurring at paleodepths ranging from ~3.4 to ~4 km in the eastern equatorial Pacific Ocean. Carbonate dissolution maxima coincide with warm phases (δ18O minima) and δ13C decreases, implying that climate-carbon cycle feedbacks fundamentally differed from the late Pleistocene glacial-interglacial pattern, where dissolution maxima correspond to δ13C maxima and δ18O minima. Carbonate dissolution cycles during the MCO were, thus, more similar to Paleogene hyperthermal patterns.

  3. Simulating Tropical Instability Waves in the Equatorial Eastern Pacific with a Coupled General Circulation Model

    Institute of Scientific and Technical Information of China (English)

    CHEN Xianyan; Masahide KIMOTO

    2009-01-01

    Satellite observations of SSTs have revealed the existence of unstable waves in the equatorial eastern Pacific and Atlantic oceans. These waves have a 20-40-day periodicity with westward phase speeds of 0.4-0.6 m s-1 and wavelengths of 1000-2000 km during boreal summer and fall.They are generally called tropical instability waves (TIWs).This study investigates TIWs simulated by a high-resolution coupled atmosphere-ocean general circulation model (AOGCM).The horizontal resolution of the model is 120 km in the atmosphere,and 30 km longitude by 20 km latitude in the ocean.Model simulations show good agreement with the observed main features associated with TIWs.The results of energetics analysis reveal that barotropic energy conversion is responsible for providing the main energy source for TIWs by extracting energy from the meridional shear of the climatological-mean equatorial currents in the mixed layer.This deeper and northward-extended wave activity appears to gain its energy through baroclinic conversion via buoyancy work,which further contributes to the asymmetric distribution of TIWs.It is estimated that the strong cooling effect induced by equatorial upwelling is partially (~30%-40%)offset by the equatorward heat flux due to TIWs in the eastern tropical Pacific during the seasons when TIWs are active.The atmospheric mixed layer just above the sea surface responds to the waves with enhanced or reduced vertical mixing.Furthermore,the changes in turbulent mixing feed back to sea surface evaporation,favoring the westward propagation of TIWs.The atmosphere to the south of the Equator also responds to TIWs in a similar way,although TIWs are much weaker south of the Equator.

  4. Blue whale population structure along the eastern South Pacific Ocean: evidence of more than one population.

    Science.gov (United States)

    Torres-Florez, J P; Hucke-Gaete, R; LeDuc, R; Lang, A; Taylor, B; Pimper, L E; Bedriñana-Romano, L; Rosenbaum, H C; Figueroa, C C

    2014-12-01

    Blue whales (Balaenoptera musculus) were among the most intensively exploited species of whales in the world. As a consequence of this intense exploitation, blue whale sightings off the coast of Chile were uncommon by the end of the 20th century. In 2004, a feeding and nursing ground was reported in southern Chile (SCh). With the aim to investigate the genetic identity and relationship of these Chilean blue whales to those in other Southern Hemisphere areas, 60 biopsy samples were collected from blue whales in SCh between 2003 and 2009. These samples were genotyped at seven microsatellite loci and the mitochondrial control region was sequenced, allowing us to identify 52 individuals. To investigate the genetic identity of this suspected remnant population, we compared these 52 individuals to blue whales from Antarctica (ANT, n = 96), Northern Chile (NCh, n = 19) and the eastern tropical Pacific (ETP, n = 31). No significant differentiation in haplotype frequencies (mtDNA) or among genotypes (nDNA) was found between SCh, NCh and ETP, while significant differences were found between those three areas and Antarctica for both the mitochondrial and microsatellite analyses. Our results suggest at least two breeding population units or subspecies exist, which is also supported by other lines of evidence such as morphometrics and acoustics. The lack of differences detected between SCh/NCh/ETP areas supports the hypothesis that eastern South Pacific blue whales are using the ETP area as a possible breeding area. Considering the small population sizes previously reported for the SCh area, additional conservation measures and monitoring of this population should be developed and prioritized.

  5. Boron isotopes reveal multiple metasomatic events in the mantle beneath the eastern North China Craton

    Science.gov (United States)

    Li, Hong-Yan; Zhou, Zhou; Ryan, Jeffrey G.; Wei, Gang-Jian; Xu, Yi-Gang

    2016-12-01

    Linkages inferred between the geochemical heterogeneity of the mantle beneath eastern Eurasia and the stagnant Pacific slab documented geophysically in its mantle transition zone are as yet not clearly characterized. In this paper we report new elemental and isotopic data for boron (B) on a suite of well-characterized Cenozoic basalts (alkali basalts, basanites and nephelinites), with ocean island basalt (OIB)-like trace element signatures from western Shandong of the eastern North China Craton (NCC). Correlations between major elements (e.g., FeOT versus SiO2), trace elements (e.g., CeN/PbN versus BaN/ThN) and radiogenic isotopes (e.g., 206Pb/204Pb versus 87Sr/86Sr) suggest these basalts are derived via the mixing of melts from two mantle components: a fluid mobile element (FME; such as Ba, K, Pb and Sr) enriched component, which is most evident in the alkali basalts, and a FME depleted mantle component that is more evident in the basanites and nephelinites. The alkali basalts in this study have lower B concentrations (1.4-2.2 μg/g) but higher δ11B (-4.9 to -1.4) values than the basanites and nephelinites (B = 2.1-5.0 μg/g; δ11B = -6.9 to -3.9), and all the samples have nearly constant B/Nb ratios between 0.03 and 0.07, similar to the observed range in B/Nb for intraplate lavas. Our high-SiO2 samples have higher δ11B than that of our low SiO2 samples, indicating that the B isotopic differences among our samples do not result from the addition of a continental crustal component in the mantle source, or direct crustal assimilation during the eruption process. The positive B versus Nb correlation suggests the B isotopic compositions of the western Shandong basalts primarily reflect the pre-eruptive compositions of their mantle sources. Correlations among B, Nd and Sr isotope signatures of the western Shandong basalts differ from those among basalts from plume settings (e.g., Azores and Hawaii), and are inconsistent with models suggesting single-step metasomatic

  6. A revised estimate of Pacific-North America motion and implications for Western North America plate boundary zone tectonics

    Science.gov (United States)

    Demets, Charles; Gordon, Richard G.; Stein, Seth; Argus, Donald F.

    1987-01-01

    Marine magnetic profiles from the Gulf of Californa are studied in order to revise the estimate of Pacific-North America motion. It is found that since 3 Ma spreading has averaged 48 mm/yr, consistent with a new global plate motion model derived without any data. The present data suggest that strike-slip motion on faults west of the San Andreas is less than previously thought, reducing the San Andreas discrepancy with geodetic, seismological, and other geologic observations.

  7. Changes in size and trends of North American sea duck populations associated with North Pacific oceanic regime shifts

    Science.gov (United States)

    Flint, Paul L.

    2013-01-01

    Broad-scale multi-species declines in populations of North American sea ducks for unknown reasons is cause for management concern. Oceanic regime shifts have been associated with rapid changes in ecosystem structure of the North Pacific and Bering Sea. However, relatively little is known about potential effects of these changes in oceanic conditions on marine bird populations at broad scales. I examined changes in North American breeding populations of sea ducks from 1957 to 2011 in relation to potential oceanic regime shifts in the North Pacific in 1977, 1989, and 1998. There was strong support for population-level effects of regime shifts in 1977 and 1989, but little support for an effect of the 1998 shift. The continental-level effects of these regime shifts differed across species groups and time. Based on patterns of sea duck population dynamics associated with regime shifts, it is unclear if the mechanism of change relates to survival or reproduction. Results of this analysis support the hypothesis that population size and trends of North American sea ducks are strongly influenced by oceanic conditions. The perceived population declines appear to have halted >20 years ago, and populations have been relatively stable or increasing since that time. Given these results, we should reasonably expect dramatic changes in sea duck population status and trends with future oceanic regime shifts.

  8. The invasive snowflake coral (Carijoa riisei in the Tropical Eastern Pacific, Colombia

    Directory of Open Access Journals (Sweden)

    Juan Armando Sánchez

    2014-02-01

    Full Text Available Carijoa riisei (Octocorallia: Cnidaria, a western Atlantic species, has been reported in the Pacific as an invasive species for nearly forty years. C. riisei has been recently observed overgrowing native octocorals at several rocky-coral littorals in the Colombian Tropical Eastern Pacific-(TEP. C. riisei has inhabited these reefs for at least 15 years but the aggressive overgrowth on other octocorals have been noted until recently. Here, we surveyed for the first time the distribution and inter-specific aggression by C. riisei in both coastal and oceanic areas colonized in the Colombian TEP (Malpelo, Gorgona and Cabo Corrientes, including preliminary multiyear surveys during 2007-2013. We observed community-wide octocoral mortalities (including local extinction of some Muricea spp. and a steady occurrence of competing and overgrowing Pacifigorgia seafans and Leptogorgia seawhips. In Gorgona Island, at two different sites, over 87% (n=77 tagged colonies of octocorals (Pacifigorgia spp. and Leptogorgia alba died as a result of C. riisei interaction and/or overgrowth between 2011 and 2013. C. riisei overgrows octocorals with an estimate at linear growth rate of about 1cm m-1. The aggressive overgrowth of this species in TEP deserves more attention and regular monitoring programs. Rev. Biol. Trop. 62 (Suppl. 1: 199-207. Epub 2014 February 01.

  9. Hawksbill turtle terra incognita: conservation genetics of eastern Pacific rookeries.

    Science.gov (United States)

    Gaos, Alexander R; Lewison, Rebecca L; Liles, Michael J; Gadea, Velkiss; Altamirano, Eduardo; Henríquez, Ana V; Torres, Perla; Urteaga, José; Vallejo, Felipe; Baquero, Andres; LeMarie, Carolina; Muñoz, Juan Pablo; Chaves, Jaime A; Hart, Catherine E; Peña de Niz, Alejandro; Chácon, Didiher; Fonseca, Luis; Otterstrom, Sarah; Yañez, Ingrid L; LaCasella, Erin L; Frey, Amy; Jensen, Michael P; Dutton, Peter H

    2016-02-01

    Prior to 2008 and the discovery of several important hawksbill turtle (Eretmochelys imbricata) nesting colonies in the EP (Eastern Pacific), the species was considered virtually absent from the region. Research since that time has yielded new insights into EP hawksbills, salient among them being the use of mangrove estuaries for nesting. These recent revelations have raised interest in the genetic characterization of hawksbills in the EP, studies of which have remained lacking to date. Between 2008 and 2014, we collected tissue samples from 269 nesting hawksbills at nine rookeries across the EP and used mitochondrial DNA sequences (766 bp) to generate the first genetic characterization of rookeries in the region. Our results inform genetic diversity, population differentiation, and phylogeography of the species. Hawksbills in the EP demonstrate low genetic diversity: We identified a total of only seven haplotypes across the region, including five new and two previously identified nesting haplotypes (pooled frequencies of 58.4% and 41.6%, respectively), the former only evident in Central American rookeries. Despite low genetic diversity, we found strong stock structure between the four principal rookeries, suggesting the existence of multiple populations and warranting their recognition as distinct management units. Furthermore, haplotypes EiIP106 and EiIP108 are unique to hawksbills that nest in mangrove estuaries, a behavior found only in hawksbills along Pacific Central America. The detected genetic differentiation supports the existence of a novel mangrove estuary "reproductive ecotype" that may warrant additional conservation attention. From a phylogeographic perspective, our research indicates hawksbills colonized the EP via the Indo-Pacific, and do not represent relict populations isolated from the Atlantic by the rising of the Panama Isthmus. Low overall genetic diversity in the EP is likely the combined result of few rookeries, extremely small

  10. Prevalence of dengue and chikungunya virus infections in north-eastern Tanzania

    DEFF Research Database (Denmark)

    Kajeguka, Debora C; Kaaya, Robert D; Mwakalinga, Steven;

    2016-01-01

    and chikungunya virus among participants presenting with malaria-like symptoms (fever, headache, rash, vomit, and joint pain) in three communities with distinct ecologies of north-eastern Tanzania. METHODS: Cross sectional studies were conducted among 1100 participants (aged 2-70 years) presenting with malaria....... Further analyses revealed that headache and joint pain were significantly associated with chikungunya IgM seropositivity. CONCLUSION: In north-eastern Tanzania, mainly chikungunya virus appears to be actively circulating in the population. Continuous surveillance is needed to determine the contribution...

  11. [Detection of antibodies of Borrelia burgdorferi among inhabitants of north-eastern Poland].

    Science.gov (United States)

    Pancewicz, S A; Januszkiewicz, A; Hermanowska-Szpakowicz, T

    1996-01-01

    The aim of this work was to estimate the detection of antibodies against Borrelia burgdorferi among inhabitants in North Eastern Poland 1765 persons from Białystok, Lomza and Suwałki voivodships were examined. Among them 1101 persons were from high-risk of exposition to ticks group (forest workers, people living close to forests). 418 (23.68%) persons from group of 1765 had antibodies against B.b. There was no difference of incidence of antibodies against B.b. in high-risk group and the others. The results show that North Eastern Poland is the endemic region of occurrence of B.b.

  12. The Structure of Genetic Diversity in Eelgrass (Zostera marina L.) along the North Pacific and Bering Sea Coasts of Alaska

    Science.gov (United States)

    Talbot, Sandra; Sage, Kevin; Rearick, Jolene; Fowler, Megan C.; Muñiz-Salazar, Raquel; Baibak, Bethany; Wyllie-Echeverria, Sandy; Cabello-Pasini, Alehandro; Ward, David H.

    2016-01-01

    Eelgrass (Zostera marina) populations occupying coastal waters of Alaska are separated by a peninsula and island archipelago into two Large Marine Ecosystems (LMEs). From populations in both LMEs, we characterize genetic diversity, population structure, and polarity in gene flow using nuclear microsatellite fragment and chloroplast and nuclear sequence data. An inverse relationship between genetic diversity and latitude was observed (heterozygosity: R2 = 0.738, P < 0.001; allelic richness: R2 = 0.327, P = 0.047), as was significant genetic partitioning across most sampling sites (θ = 0.302, P < 0.0001). Variance in allele frequency was significantly partitioned by region only in cases when a population geographically in the Gulf of Alaska LME (Kinzarof Lagoon) was instead included with populations in the Eastern Bering Sea LME (θp = 0.128–0.172; P < 0.003), suggesting gene flow between the two LMEs in this region. Gene flow among locales was rarely symmetrical, with notable exceptions generally following net coastal ocean current direction. Genetic data failed to support recent proposals that multiple Zostera species (i.e. Z. japonica and Z. angustifolia) are codistributed with Z. marina in Alaska. Comparative analyses also failed to support the hypothesis that eelgrass populations in the North Atlantic derived from eelgrass retained in northeastern Pacific Last Glacial Maximum refugia. These data suggest northeastern Pacific populations are derived from populations expanding northward from temperate populations following climate amelioration at the terminus of the last Pleistocene glaciation.

  13. Influences of the El Nino Southern Oscillation and the Pacific Decadal Oscillation on the Timing of the North American Spring

    Science.gov (United States)

    McCabe, Gregory J.; Ault, Toby R.; Cook, Benjamin I.; Betancourt, Julio L.; Schwartz, Mark D.

    2012-01-01

    Detrended, modelled first leaf dates for 856 sites across North America for the period 1900-2008 are used to examine how the El Nino Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) separately and together might influence the timing of spring. Although spring (mean March through April) ENSO and PDO signals are apparent in first leaf dates, the signals are not statistically significant (at a 95% confidence level (p Nino and positive PDO conditions. An analysis of the spatial distributions of first leaf dates for separate and combined ENSO/PDO conditions features a northwest-southeast dipole that is significantly (at p <0.05) different than the distributions for neutral conditions. The nature of the teleconnection between Pacific SST's and first leaf dates is evident in comparable composites for detrended sea level pressure (SLP) in the spring months. During positive ENSO/PDO, there is an anomalous flow of warm air from the southwestern US into the northwestern US and an anomalous northeasterly flow of cold air from polar regions into the eastern and southeastern US. These flow patterns are reversed during negative ENSO/PDO. Although the magnitudes of first leaf date departures are not necessarily significantly related to ENSO and PDO, the spatial patterns of departures are significantly related to ENSO and PDO. These significant relations and the long-lived persistence of SSTs provide a potential tool for forecasting the tendencies for first leaf dates to be early or late.

  14. THE TROPICAL CONNECTION BETWEEN THE ATLANTIC SECTOR ICE CORES AND THE NORTH PACIFIC MT LOGAN ICE CORE

    Science.gov (United States)

    Fisher, D. A.

    2009-12-01

    The stable isotope record from the Mt Logan, Yukon, Canada ice core spans the late Glacial to present and shows very large and sudden variations in O18 during the Holocene . It is hypothesized that they are driven by changes in the water sources ,which in turn, are determined by the state of ENSO. There seems to be no correlations between the Logan ice core isotope record and those from the North Atlantic (Greenland and Eastern Canadian Arctic). Using the stacked and co-dated Greenland and Eastern Canadian Arctic ice core records from the Holocene, it is possible to reproduce the Logan isotope record by subtracting the stacked Atlantic record from itself with an 1100 year lag. The correlations obtainable are -0.43 for 50 year average series. This correlation is significant at the 99.8 % level . The 1100 lag has also been found in previous studies comparing the Greenland to Antarctic ice cores (Stocker and Johnsen,2003). It is argued that such a lagged difference series is a proxy for the difference between the ocean water surface and deep temperatures in the tropical Pacific . ENSO’s amplitude is driven by this temperature difference, (Sun 2000). When the deep water is too warm, then the difference is too small to produce ENSO oscillations and strong tropical easterly winds persist (ie strong and constant La Nina). The ice core records from Mt Logan , Greenland and Eastern Arctic Canada all point to a similar history of ENSO oscillation strength. Prior to ~ 4200 BP the strong and constant La Nina tended to drive the tropical Pacific winds and moisture across to produce strong and reliable monsoons. Since 4200 BP the “modern” and variable pattern has been in place. There was a smaller scale shift about 1840 AD . For about a couple of centuries prior to 1840 AD , La Nina was in charge and after there were the oscillations that are thought of as normal. If the 1100 year lag between surface and bottom temperatures is true and if the bottom temperatures are echoes

  15. Comparative Resilience in Five North Pacific Regional Salmon Fisheries

    Directory of Open Access Journals (Sweden)

    Xanthippe Augerot

    2010-06-01

    Full Text Available Over the past century, regional fisheries for Pacific salmon (Oncorhynchus spp. have been managed primarily for their provisioning function, not for ecological support and cultural significance. We examine the resilience of the regional salmon fisheries of Japan, the Russian Far East, Alaska, British Columbia, and Washington-Oregon-California (WOC in terms of their provisioning function. Using the three dimensions of the adaptive cycle - capital, connectedness, and resilience - we infer the resilience of the five fisheries based on a qualitative assessment of capital accumulation and connectedness at the regional scale. In our assessment, we evaluate natural capital and connectedness and constructed capital and connectedness. The Russian Far East fishery is the most resilient, followed by Alaska, British Columbia, Japan, and WOC. Adaptive capacity in the fisheries is contingent upon high levels of natural capital and connectedness and moderate levels of constructed capital and connectedness. Cross-scale interactions and global market demand are significant factors in reduced resilience. Greater attention to ecological functioning and cultural signification has the potential to increase resilience in Pacific salmon ecosystems.

  16. Biogeochemical characteristics of a long-lived anticyclonic eddy in the eastern South Pacific Ocean

    Directory of Open Access Journals (Sweden)

    M. Cornejo

    2015-09-01

    Full Text Available Eastern boundary upwelling systems are characterized by high productivity that often leads to subsurface hypoxia on the shelf. Mesoscale eddies are important, frequent, and persistent features of circulation in these regions, transporting physical, chemical and biological properties from shelves to the open ocean. In austral fall of 2011, during the Tara Oceans expedition, a subsurface layer (200–400 m in which the concentration of oxygen was very low (−1 of O2 was observed in the eastern South Pacific, ~ 900 km offshore (30° S, 81° W. Satellite altimetry combined with CTD observations associated the local oxygen anomaly with an intrathermocline, anticyclonic, mesoscale eddy with a diameter of about 150 km. The eddy contained Equatorial Subsurface Water (ESSW that at this latitude is normally restricted near the coast. Undersaturation (44 % of nitrous oxide (N2O and nitrite accumulation (> 0.5 μM gave evidence for denitrification in this water mass. Based on satellite altimetry, we tracked the eddy back to its region of formation on the coast of central Chile (36.1° S, 74.6° W. We estimate that the eddy formed in April 2010. Field studies conducted on the Chilean shelf in June 2010 provided approximate information on initial O2 and N2O concentrations of "source water" in the region at the time of eddy formation. Concentrations of both O2 and N2O in the oxygen minimum zone (OMZ of the offshore eddy were lower than its surroundings or "source water" on the shelf, suggesting that these chemical species were consumed as the eddy moved offshore. Estimates of apparent oxygen utilization rates at the OMZ of the eddy ranged from 0.29 to 44 nmol L−1 d−1 and the rate of N2O consumption was 3.92 nmol L−1 d−1. Our results show that mesoscale eddies in the ESP not only transport physical properties of the ESSW from the coast to the ocean interior, but also export and transform biogeochemical properties, creating suboxic environments in the

  17. The Colombia Current: An Eastern Tropical Pacific Coastal Current, Early Oceanographic Characteristics

    Science.gov (United States)

    Rodriguez-Rubio, E.

    2007-05-01

    Newly gathered hydrographic data from the Colombia Pacific Ocean is combined with remote sensing data to reassess the properties of the costal current named Colombian Current by Wooster (1959). The Colombian Pacific Ocean is located between 84°-76°W and 1°30'-5°N (oceanic zone), 1°30'- 7°N (coastal zone): This area is well-known also like Panama Bight. New hydrographic data were occupied along the Colombian Pacific coast during March of 2006, making 41 stations with measurements of CTD until a maximum depth of 1200 m, depending on the depth of the marine bottom. On the other hand, sea surface temperatures (SST) were obtained from the MODIS-AQUA satellite and sea surface wind speed and wind direction stem from QuickScat, both averaged for March 2006. Hydrographic grid layers necessary to obtain dynamic topography variable were made with objective mapping calculating is not total dynamic height, but the dynamic height between consecutive levels or "thickness". The purpose of this methodology is that in very coastal campaigns it can have a substantial number of stations that do not arrive at the reference level. Finally geostrophic velocity was computed for the Colombian Current area at several layers. The coast was characterized by low salinities due to river runoff in the North zone. The sea surface temperature during the month of March of 2006 was especially low in the oceanic zone, reaching temperatures between 19°C and 24°C.The dynamic topography indicated the presence of a surface coastal current flowing towards the north and a crosscurrent to 400 m of depth never before described. The wind corresponded to the pattern of the wind jet of Panama. During March the ITCZ moves south, drawing the Panama jet across the Isthmus and over the Pacific. Upwelling curl associated with the left (southeast) flank of this jet generates a cyclonic eddy in the Panama Bight and SST cooling in its center. In the Panama Bight, the curl dipole produces a cyclonic circulation

  18. 77 FR 14350 - North Pacific Fishery Management Council; Public Meeting

    Science.gov (United States)

    2012-03-09

    ...; Public Meeting AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric... Hilton Hotel, 500 West 3rd Avenue, King Salmon/Illiamna Room, Anchorage, AK. Council address: North... INFORMATION CONTACT: Jane DiCosimo, Council staff; telephone: (907) 271-2809. SUPPLEMENTARY INFORMATION:...

  19. Regime Shifts in the North Pacific Simulated by a COADS-driven Isopycnal Model

    Institute of Scientific and Technical Information of China (English)

    王东晓; 王佳; 吴立新; 刘征宇

    2003-01-01

    The Miami Isopycnal Coordinate Ocean Model (MICOM) is adopted to simulate the interdecadalvariability in the Pacific Ocean with most emphasis on regime shifts in the North Pacific. The compu-tational domain covers 60°N to 40°S with an enclosed boundary condition for momentum flux, whereasthere are thermohaline fluxes across the southern end as a restoring term. In addition, sea surface salinityof the model relaxes to the climatological season cycle, which results in climatological fresh water fluxes.Surface forcing functions from January 1945 through December 1993 are derived from the ComprehensiveOcean and Atmospheric Data Set (COADS). Such a numerical experiment reproduces the observed evo-lution of the interdecadal variability in the heat content over the upper 400-m layer by a two-year lag.Subduction that occurs at the ventilated thermocline in the central North Pacific is also been simulatedand the subducted signals propagate from 35°N to 25°N, taking about 8 to 10 years, in agreement with theeXpendable Bathy Thermograph observation over recent decades. Interdecadal signals take a southwest-ward and downward path rather than westward propagation, meaning they are less associated with thebaroclinic planetary waves. During travel, the signals appear to conserve potential vorticity. Therefore,the ventilated thermocline and related subduction are probably the fundamental physics for interdecadalvariability in the mid-latitude subtropics of the North Pacific.

  20. Interdecadal shift in the western North Pacific Summer SST anomaly in the late 1980s

    Institute of Scientific and Technical Information of China (English)

    WU BingYi; ZHANG RenHe

    2007-01-01

    An interdecadal shift in summer (June-August) sea surface temperature (SST) variations during the period of 1968―2002 was identified in the late 1980s, which is characterized by a phase alternating from negative to positive phases of the leading mode of the empirical orthogonal function (EOF) analysis of the summer monthly mean SST in the Pacific domain 100°―180°E and 0°―40°N, accounting for 30.5% of the total variance. During the period of 1968―1987, the leading mode with a mean negative phase state (mean standard deviation = -0.586) controlled SST variability in the western North Pacific. Correspondingly, negative SST anomalies occupied the western North Pacific south of Japan and Chinese marginal seas. During the period of 1988―2002, the leading mode shifted to its strong positive polarity (mean standard deviation = 0.781), thus positive SST anomalies appeared in the western North Pacific. Accompanied by the interdecadal shift in summer mean SST, summer mean rainfall increased in southern and southeastern China during the late period, particularly in southeastern China where increase in summer mean rainfall exceeded 40 mm, at the 0.05 significance level.

  1. North Pacific decadal variability in the CMIP5 last millennium simulations

    Science.gov (United States)

    Fleming, Laura E.; Anchukaitis, Kevin J.

    2016-12-01

    The Pacific ocean-atmosphere system exerts an important influence on the climate of Asia and North America, but the limited length of the observational record prevents a complete understanding of its bidecadal and multidecadal time scales. Paleoclimate reconstructions provide one source of information on longer time scales, although they differ in their estimation of the behavior of the Pacific decadal oscillation (PDO) prior to the instrumental period. Forced general circulation model simulations offer complementary long-term perspectives on both the history and dynamics of this important mode of variability. Here, we analyze the PDO in the ensemble of CMIP5/PMIP3 last millennium (past1000 + historical) simulations. We evaluate the modeled spatial, temporal, and spectral characteristics of this mode, as well as teleconnections between North Pacific variability and global climate. All models produce a mode of North Pacific variability over the last millennium with spatial patterns and spectral power density similar to observations. CCSM, FGOALS, and IPSL best reproduce observed spatial patterns, spectral characteristics, and teleconnections to terrestrial regions used in paleoclimate proxy reconstructions. In these simulations, the PDO shows no consistent response to solar or volcanic forcing.

  2. Nitrous oxide emissions from irrigated cotton in north eastern Australia

    Science.gov (United States)

    Grace, P.; Rowlings, D.; Weier, K.; Rochester, I.; Kiese, R.; Butterbach-Bahl, K.

    2009-04-01

    Cotton is one of many agricultural industries in Australia heavily reliant on nitrogenous fertilizers and water storages to maintain high levels of production. Cotton-based farming systems are therefore labelled as potentially high-risk agricultural systems with respect to gaseous losses of nitrogen to the atmosphere. The on-farm study was undertaken at Dalby in the Darling Downs region of Queensland in north eastern Australia. The field was furrow irrigated and had been under continuous cotton (with winter bare fallow) for 10 years. The block was conventionally tilled, with a spraying regime typical for cotton production in this area. The black clay (with a surface clay content of 68%) and soil organic carbon content (0-10 cm) of 1.0% and a pH of 8.5, is typical of the region. During the the 2006/07 season, soil water (0-50 cm with Enviroscan), mineral nitrogen (0-10 cm) and crop production data was also collected to develop accurate models for predicting greenhouse gas emissions as a function of key chemical, physical and biological processes and specific management events. The 2006/07 experiment also attempted to directly measure the specific losses of N2O and N2 from a single application of N fertiliser using 15N isotopically labelled urea. The automated greenhouse gas measuring system (developed by Butterbach-Bahl et al.) consists of six chambers connected to sequential sampling unit, a gas chromatograph (equipped with both electron capture and flame ionization detectors for nitrous oxide and methane analysis respectively), and a Licor for carbon dioxide. To meet the demand for high mobility, the sample acquisition and analysis system is trailer mounted. During a normal sampling period, the chambers were closed for 90 minutes (unless temperatures within the chambers exceeded 55oC). The sampling program ensured that that a single gas sample was drawn back from each chamber every 20 minutes. To facilitate 15N gas sampling, Swagelok T-pieces were inserted into

  3. Observation-based estimate of the Fukushima radionuclide in the North Pacific

    Science.gov (United States)

    Yoshida, Sachiko; Jayne, Steven; Macdonald, Alison; Buesseler, Ken; Rypina, Irina

    2014-05-01

    Contaminated waters from Fukushima nuclear power plant (FNPP) were discharged directly into the North Pacific Ocean in March 2011. Coastal current system in this region and time scale of the water exchange with the open ocean is not well understood, however both observational evidence and numerical model simulation results indicate relatively rapid advection of contaminants eastward into the highly energetic mixed water region in the confluence of the Kuroshio and Oyashio. Surface drifters deployed near the FNPP in early summer 2011 show trajectories crossing the North Pacific generally following the large scale ocean circulation after one year. Previously obtained cesium (Cs) samples from multiple cruises near FNPP and off shore region between 2011 and 2013 are collected and evaluated to diagnose the propagating Cs signal crossing North Pacific Ocean. In this presentation, we use radionuclides of Fukushima origin as a tracer to understand the North Pacific circulation and mixing process after two years of release. Large numbers of the observation are repeatedly took place near shore where Cs shows still relatively higher about 10-30 Bq/m3 in 2013. Temperature-salinity (T-S) properties for the available hydrographic data indicate that the majority of the samples were obtained in the region where the water is highly influenced by the warm-salty Kuroshio origin water. Depth profiles of 35N section in March-May 2013 cruise of the U.S. Climate Variability and Predictability and Carbon (CLIVAR) repeat Hydrography sections are examined to track the radionuclide penetration into the subsurface ocean and the subduction pathways along isopycnal surfaces. Available large drifter datasets that accumulated over decades of field work can guide us in estimating the spread of these radionuclides. By applying an innovative statistical analysis to the drifter data, we investigate the spreading of radionuclides in the Pacific Ocean over 5-year time scales.

  4. 76 FR 77021 - In the Matter of Carolina Power & Light Company, North Carolina Eastern Municipal Power Agency...

    Science.gov (United States)

    2011-12-09

    ... COMMISSION In the Matter of Carolina Power & Light Company, North Carolina Eastern Municipal Power Agency... Carolina Power & Light Company (CP&L, the licensee) and North Carolina Eastern Municipal Power Agency are... single unit Westinghouse three-loop pressurized water reactor located in Wake and Chatham Counties,...

  5. 76 FR 77024 - In the Matter of Carolina Power & Light Company North Carolina Eastern, Municipal Power Agency...

    Science.gov (United States)

    2011-12-09

    ... Carolina Power & Light Company North Carolina Eastern, Municipal Power Agency, Brunswick Steam Electric Plant, Units 1 and 2; Order Approving Indirect Transfer of Control of Licenses I Carolina Power & Light Company (CP&L, the licensee) and North Carolina Eastern Municipal Power Agency are the owners of...

  6. Modeling the inorganic bromine partitioning in the tropical tropopause layer over the eastern and western Pacific Ocean

    Directory of Open Access Journals (Sweden)

    M. A. Navarro

    2017-08-01

    Full Text Available The stratospheric inorganic bromine (Bry burden arising from the degradation of brominated very short-lived organic substances (VSLorg and its partitioning between reactive and reservoir species is needed for a comprehensive assessment of the ozone depletion potential of brominated trace gases. Here we present modeled inorganic bromine abundances over the Pacific tropical tropopause based on aircraft observations of VSLorg from two campaigns of the Airborne Tropical TRopopause EXperiment (ATTREX 2013, carried out over the eastern Pacific, and ATTREX 2014, carried out over the western Pacific and chemistry-climate simulations (along ATTREX flight tracks using the specific meteorology prevailing. Using the Community Atmosphere Model with Chemistry (CAM-Chem we model that BrO and Br are the daytime dominant species. Integrated across all ATTREX flights, BrO represents ∼ 43 and 48 % of daytime Bry abundance at 17 km over the western and eastern Pacific, respectively. The results also show zones where Br / BrO > 1 depending on the solar zenith angle (SZA, ozone concentration, and temperature. On the other hand, BrCl and BrONO2 were found to be the dominant nighttime species with ∼  61 and 56 % of abundance at 17 km over the western and eastern Pacific, respectively. The western-to-eastern differences in the partitioning of inorganic bromine are explained by different abundances of ozone (O3, nitrogen dioxide (NO2, total inorganic chlorine (Cly, and the efficiency of heterogeneous reactions of bromine reservoirs (mostly BrONO2 and HBr occurring on ice crystals.

  7. Modeling the inorganic bromine partitioning in the tropical tropopause layer over the eastern and western Pacific Ocean

    Science.gov (United States)

    Navarro, Maria A.; Saiz-Lopez, Alfonso; Cuevas, Carlos A.; Fernandez, Rafael P.; Atlas, Elliot; Rodriguez-Lloveras, Xavier; Kinnison, Douglas; Lamarque, Jean-Francois; Tilmes, Simone; Thornberry, Troy; Rollins, Andrew; Elkins, James W.; Hintsa, Eric J.; Moore, Fred L.

    2017-08-01

    The stratospheric inorganic bromine (Bry) burden arising from the degradation of brominated very short-lived organic substances (VSLorg) and its partitioning between reactive and reservoir species is needed for a comprehensive assessment of the ozone depletion potential of brominated trace gases. Here we present modeled inorganic bromine abundances over the Pacific tropical tropopause based on aircraft observations of VSLorg from two campaigns of the Airborne Tropical TRopopause EXperiment (ATTREX 2013, carried out over the eastern Pacific, and ATTREX 2014, carried out over the western Pacific) and chemistry-climate simulations (along ATTREX flight tracks) using the specific meteorology prevailing. Using the Community Atmosphere Model with Chemistry (CAM-Chem) we model that BrO and Br are the daytime dominant species. Integrated across all ATTREX flights, BrO represents ˜ 43 and 48 % of daytime Bry abundance at 17 km over the western and eastern Pacific, respectively. The results also show zones where Br / BrO > 1 depending on the solar zenith angle (SZA), ozone concentration, and temperature. On the other hand, BrCl and BrONO2 were found to be the dominant nighttime species with ˜ 61 and 56 % of abundance at 17 km over the western and eastern Pacific, respectively. The western-to-eastern differences in the partitioning of inorganic bromine are explained by different abundances of ozone (O3), nitrogen dioxide (NO2), total inorganic chlorine (Cly), and the efficiency of heterogeneous reactions of bromine reservoirs (mostly BrONO2 and HBr) occurring on ice crystals.

  8. Sinking velocity of particulate radiocesium in the northwestern North Pacific

    Science.gov (United States)

    Honda, Makio C.; Kawakami, Hajime

    2014-06-01

    Sinking particles (SP) were collected by time series sediment traps at two depths in the northwestern Pacific before and after the Fukushima Daiichi Nuclear Power Plant accident, and accident-derived particulate radiocesium was measured. Radiocesium (137Cs) was first detected at 500 m (4810 m) about 2 weeks (1 month) after the accident. 137Cs of SP collected over 1 year revealed that the time lag between two depths was larger than that for the first 137Cs detection (about 2 weeks). We estimated the transient sinking velocity (SV) from the cumulative temporal 137Cs flux and the time lags at the two depths. Although the SV of SP collected in very early period was large, the estimated SV of most particulate 137Cs (about 80%) was about 50 m d-1. Based on comparison of 137Cs concentration in total SP with that in SP without organic materials, we suspect that most of the 137Cs was likely incorporated into aluminosilicates.

  9. Big insights from tiny peridotites: Evidence for persistence of Precambrian lithosphere beneath the eastern North China Craton

    Science.gov (United States)

    Liu, Jingao; Rudnick, Roberta L.; Walker, Richard J.; Xu, Wen-liang; Gao, Shan; Wu, Fu-yuan

    2015-05-01

    Previous studies have shown that the eastern North China Craton (NCC) lost its ancient lithospheric mantle root during the Phanerozoic. The temporal sequence, spatial extent, and cause of the lithospheric thinning, however, continue to be debated. Here we report olivine compositions, whole-rock Re-Os isotopic systematics, and platinum-group element abundances of small ( 92) lithospheric mantle is largely absent. Osmium isotopic data suggest the Wudi peridotites experienced melt depletion primarily during the Paleoproterozoic (~ 1.8 Ga), although an Archean Os model age for one xenolith indicates incorporation of a minor component of Archean lithospheric mantle. These data suggest that a previously unrecognized Paleoproterozoic orogenic event removed and replaced the original Archean lithospheric mantle beneath the sedimentary basin at the southern edge of the Bohai Sea. By contrast, the Fuxin peridotites, entrained in Cretaceous basalts that crop out along the northern edge of the eastern NCC, document the coexistence of both ancient (≥ 2.3 Ga) and modern lithospheric mantle components. Here, the original Late Archean-Early Paleoproterozoic lithospheric mantle was, at least partially, removed and replaced prior to 100 Ma. Combined with literature data, our results show that removal of the original Archean lithosphere occurred within Proterozoic collisional orogens, and that replacement of Precambrian lithosphere during the Mesozoic may have been spatially associated with the collisional boundaries and the strike-slip Tan-Lu fault, as well as the onset of Paleo-Pacific plate subduction.

  10. Genetic species identification and population structure of Halophila (Hydrocharitaceae) from the Western Pacific to the Eastern Indian Ocean.

    Science.gov (United States)

    Nguyen, Vy X; Detcharoen, Matsapume; Tuntiprapas, Piyalap; Soe-Htun, U; Sidik, Japar B; Harah, Muta Z; Prathep, Anchana; Papenbrock, Jutta

    2014-04-30

    The Indo-Pacific region has the largest number of seagrass species worldwide and this region is considered as the origin of the Hydrocharitaceae. Halophila ovalis and its closely-related species belonging to the Hydrocharitaceae are well-known as a complex taxonomic challenge mainly due to their high morphological plasticity. The relationship of genetic differentiation and geographic barriers of H. ovalis radiation was not much studied in this region. Are there misidentifications between H. ovalis and its closely related species? Does any taxonomic uncertainty among different populations of H. ovalis persist? Is there any genetic differentiation among populations in the Western Pacific and the Eastern Indian Ocean, which are separated by the Thai-Malay peninsula? Genetic markers can be used to characterize and identify individuals or species and will be used to answer these questions. Phylogenetic analyses of the nuclear ribosomal internal transcribed spacer region based on materials collected from 17 populations in the Western Pacific and the Eastern Indian Ocean showed that some specimens identified as H. ovalis belonged to the H. major clade, also supported by morphological data. Evolutionary divergence between the two clades is between 0.033 and 0.038, much higher than the evolutionary divergence among H. ovalis populations. Eight haplotypes were found; none of the haplotypes from the Western Pacific is found in India and vice versa. Analysis of genetic diversity based on microsatellite analysis revealed that the genetic diversity in the Western Pacific is higher than in the Eastern Indian Ocean. The unrooted neighbor-joining tree among 14 populations from the Western Pacific and the Eastern Indian Ocean showed six groups. The Mantel test results revealed a significant correlation between genetic and geographic distances among populations. Results from band-based and allele frequency-based approaches from Amplified Fragment Length Polymorphism showed that all

  11. Prolonged El Niño conditions in 2014-2015 and the rapid intensification of Hurricane Patricia in the eastern Pacific

    Science.gov (United States)

    Foltz, Gregory R.; Balaguru, Karthik

    2016-10-01

    Hurricane Patricia was the most intense tropical cyclone on record in the eastern North Pacific or Atlantic, reaching a peak intensity of 95 m s-1 only 30 h after attaining hurricane status (33 m s-1). Here it is shown that exceptionally warm sea surface temperatures (SSTs), a deeper than normal thermocline, and strong near-surface salinity stratification all aided Patricia's rapid intensification, combining to increase its Potential Intensity by 1-14 m s-1. Anomalous surface warming and thermocline deepening along Patricia's track were driven by prolonged El Niño conditions during 2014-2015 and punctuated by the buildup to the extreme El Niño of 2015-2016. In the region where Patricia intensified, SST was 1.5° C higher and sea surface height was 10 cm higher compared to conditions during the last extreme El Niño in 1997, emphasizing the extraordinary nature of the 2015 anomalies.

  12. Homotopy perturbation method of equatorial eastern Pacific for the El Ni(n)o-Southern Oscillation mechanism

    Institute of Scientific and Technical Information of China (English)

    Mo Jia-Qi; Lin Wan-Tao

    2005-01-01

    The EI Ni(n)o/La Ni(n)a and the Southern Oscillation (ENSO) is an interannual phenomenon involved in the tropical Pacific ocean-atmosphere interactions. In this paper, the aim is to create an asymptotic solving method of nonlinear equation for the ENSO models. And based on a class of oscillator of the ENSO models, employing the method of homotopic mapping, the approximation solution of corresponding problem is studied. It is proven from the results that the homotopic method can be used for analysing the sea surface temperature anomaly in the equatorial eastern Pacific and the thermocline depth anomaly of the atmosphere-ocean oscillation for ENSO model.

  13. Expanding diversity in the mantis shrimps: two new genera from the eastern and western Pacific (Crustacea: Stomatopoda: Squillidae

    Directory of Open Access Journals (Sweden)

    Cara Van Der Wal

    Full Text Available Abstract Squillidae is the largest family in the Stomatopoda, with 47 genera to date. Phylogenetic analyses have shown Squilla Fabricius, 1787 and Oratosquilla Manning, 1968 to be para- or polyphyletic. Two poorly documented species within these genera, Squilla parva Bigelow, 1891 (eastern Pacific and Oratosquilla kempi (Schmitt, 1931 (western Pacific are not closely related to the respective type species of the genera in which they are currently placed. We herein redescribe S. parva and O. kempi based on type and other material, and propose two new genera for their reception, increasing the number of squillid genera to 49.

  14. Regional warming chnages fish species richness in the eastern North Atlantic Ocean

    NARCIS (Netherlands)

    Hofstede, ter R.; Hiddink, J.G.; Rijnsdorp, A.D.

    2010-01-01

    Regional warming causes changes in local communities due to species extinctions and latitudinal range shifts. We show that the species richness of fish in 3 regional seas in the eastern North Atlantic Ocean has changed over time (1997 to 2008), and we relate this to higher water temperatures and the

  15. Mithun : The pride animal of north-eastern hilly region of India

    Directory of Open Access Journals (Sweden)

    M. G. Shisode

    Full Text Available Mithun, the pride animal called as ‘Cattle of Hilly Region’ of north-eastern hilly region of India and tropical rain forest of China. The animal plays an important role in the day to day socio-economic life of the local tribal population. Mithun (Bos frontalis is a rear species of livestock and is found in the north-eastern region of our country like Arunachal Pradesh (75 per cent of the total population, Nagaland (60 per cent, Manipur (0.8 per cent andMizoram (0.1 per cent having total population 0.25 million according to census 2003 and also very meager in Myanmar, Bhutan, and Bangladesh. The animal has got good potential for production of quality meat, milk and leather. Mithun is the ‘Cattle of Hilly Region’ and is one of the domesticated animals from the North-eastern hilly region and mainly found in tropical rain forest of North-eastern hilly region. Very meager population is found inMyanmar, Bhutan and China. There are four defined mithun strains depending up on the geographical areas namely Arunachal, Nagaland, Manipur and Mizoram strains, respectively. [Vet World 2009; 2(12.000: 480-481

  16. The anamorphic state of Leveillula taurica recorded on Cleome spinosa in north-eastern Brazil

    Directory of Open Access Journals (Sweden)

    Carlos AC

    2012-05-01

    Full Text Available The anamorphic state of Leveillula taurica was found causing a powdery mildew disease on Cleome spinosa in north-eastern Brazil. Its chasmothecial state was not observed on the collected samples. The fungus is illustrated and described. This report represents the first record of this fungus on Cleome spinosa in Brazil.

  17. Pollinators of the invasive plant, yellow starthistle (Centaurea solstitialis), in north-eastern Oregon, USA

    Science.gov (United States)

    James McIver; Robbin Thorp; Karen Erickson

    2009-01-01

    The potential pollinators of yellow starthistle (Centaurea solstitialis) were surveyed at six sites in north-eastern Oregon, USA, between May and September from 2000 to 2002. The objective of the study was to determine the species composition and relative abundance of the insects that visited yellow starthistle throughout the flowering season and...

  18. The south-eastern North Sea : losses of vertebrate fauna during the past 2000 years

    NARCIS (Netherlands)

    Wolff, WJ

    2000-01-01

    At least 31 species of marine mammals, marine and coastal birds, and marine and anadromous fish have disappeared temporarily or permanently from the coasts of The Netherlands and in most cases also from the south-eastern North Sea (south of 54 degrees N) during the past 2000 years-In 18-22 cases, th

  19. Data on the macromycetes flora of the North-Eastern Ploand

    Directory of Open Access Journals (Sweden)

    Longin Olesiński

    2014-08-01

    Full Text Available The list of 352 macromycetes (Asco- and Basidiomycetes collected in the North-Eastern Poland is given. It is the first part of mycofloristic investigation in this region conducted in the years 1964-1997 by latter author, and 1981-1982, by former autor.;

  20. A hidden early source of information on north-eastern Brazilian zoology

    NARCIS (Netherlands)

    Boeseman, M.

    1994-01-01

    Attention is drawn to some hitherto overlooked paragraphs on the north-eastern Brazilian fauna hid- den in a historiographic account of Count Johan Maurits' govenorship (1637-1644), published by Caspar van Baerle (Barlaeus) in 1647, a year before the publication of Marcgrave & Piso's famous Historia

  1. Maloprim malaria prophylaxis in children living in a holoendemic village in north-eastern Tanzania

    DEFF Research Database (Denmark)

    Lemnge, M M; Msangeni, H A; Rønn, A M;

    1997-01-01

    A randomized, double-'blind', placebo-controlled trial of weekly Maloprim (dapsone-pyrimethamine, D-P) for malaria prophylaxis was conducted at Magoda village in north-eastern Tanzania. The effect of D-P on the incidence of clinical malaria, Plasmodium falciparum prevalence and density, splenomeg...

  2. Field Guide for the Biological Control of Weeds in Eastern North America

    Science.gov (United States)

    This field guide provides information about invasive weeds in Eastern North America and their associated biological control agents. Information about plant identification and ecology is provided through photographs and descriptions for each weed species. The guide also includes photographs of the bi...

  3. North pacific right whale surveys conducted in the Bering Sea and North Pacific Ocean by Alaska Fisheries Science Center, National Marine Mammal Laboratory from 2007-08-01 to 2011-09-10 (NCEI Accession 0133935)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The North Pacific right whale (NPRW) was heavily hunted between the 17th and the 20th centuries. Protection was supposedly afforded by international treaties in the...

  4. Centennial changes in North Pacific anoxia linked to tropical trade winds

    Science.gov (United States)

    Deutsch, Curtis; Berelson, William; Thunell, Robert; Weber, Thomas; Tems, Caitlin; McManus, James; Crusius, John; Ito, Taka; Baumgartner, Timothy; Ferreira, Vicente; Mey, Jacob; van Geen, Alexander

    2014-01-01

    Climate warming is expected to reduce oxygen (O2) supply to the ocean and expand its oxygen minimum zones (OMZs). We reconstructed variations in the extent of North Pacific anoxia since 1850 using a geochemical proxy for denitrification (δ15N) from multiple sediment cores. Increasing δ15N since ~1990 records an expansion of anoxia, consistent with observed O2 trends. However, this was preceded by a longer declining δ15N trend that implies that the anoxic zone was shrinking for most of the 20th century. Both periods can be explained by changes in winds over the tropical Pacific that drive upwelling, biological productivity, and O2 demand within the OMZ. If equatorial Pacific winds resume their predicted weakening trend, the ocean’s largest anoxic zone will contract despite a global O2 decline.

  5. Oceanography. Centennial changes in North Pacific anoxia linked to tropical trade winds.

    Science.gov (United States)

    Deutsch, Curtis; Berelson, William; Thunell, Robert; Weber, Thomas; Tems, Caitlin; McManus, James; Crusius, John; Ito, Taka; Baumgartner, Timothy; Ferreira, Vicente; Mey, Jacob; van Geen, Alexander

    2014-08-08

    Climate warming is expected to reduce oxygen (O2) supply to the ocean and expand its oxygen minimum zones (OMZs). We reconstructed variations in the extent of North Pacific anoxia since 1850 using a geochemical proxy for denitrification (δ(15)N) from multiple sediment cores. Increasing δ(15)N since ~1990 records an expansion of anoxia, consistent with observed O2 trends. However, this was preceded by a longer declining δ(15)N trend that implies that the anoxic zone was shrinking for most of the 20th century. Both periods can be explained by changes in winds over the tropical Pacific that drive upwelling, biological productivity, and O2 demand within the OMZ. If equatorial Pacific winds resume their predicted weakening trend, the ocean's largest anoxic zone will contract despite a global O2 decline. Copyright © 2014, American Association for the Advancement of Science.

  6. Distant Influence of Kuroshio Eddies on North Pacific Weather Patterns?

    Science.gov (United States)

    Ma, Xiaohui; Chang, Ping; Saravanan, R.; Montuoro, Raffaele; Hsieh, Jen-Shan; Wu, Dexing; Lin, Xiaopei; Wu, Lixin; Jing, Zhao

    2015-12-01

    High-resolution satellite measurements of surface winds and sea-surface temperature (SST) reveal strong coupling between meso-scale ocean eddies and near-surface atmospheric flow over eddy-rich oceanic regions, such as the Kuroshio and Gulf Stream, highlighting the importance of meso-scale oceanic features in forcing the atmospheric planetary boundary layer (PBL). Here, we present high-resolution regional climate modeling results, supported by observational analyses, demonstrating that meso-scale SST variability, largely confined in the Kuroshio-Oyashio confluence region (KOCR), can further exert a significant distant influence on winter rainfall variability along the U.S. Northern Pacific coast. The presence of meso-scale SST anomalies enhances the diabatic conversion of latent heat energy to transient eddy energy, intensifying winter cyclogenesis via moist baroclinic instability, which in turn leads to an equivalent barotropic downstream anticyclone anomaly with reduced rainfall. The finding points to the potential of improving forecasts of extratropical winter cyclones and storm systems and projections of their response to future climate change, which are known to have major social and economic impacts, by improving the representation of ocean eddy-atmosphere interaction in forecast and climate models.

  7. Dissolved iron distribution in the tropical and sub tropical South Eastern Pacific

    Directory of Open Access Journals (Sweden)

    S. Blain

    2008-02-01

    Full Text Available Dissolved iron (DFe distributions (<0.2 μm were determined in the upper water column (0–400 m of the south eastern tropical and subtropical Pacific, in October–November 2004. Data were collected along a transect extending from the Marquesas Islands to the Chilean coast with most of the stations located in the south Pacific gyre. The concentrations of DFe presented large variability with highest values observed at both extremities of the transect. In the Chilean upwelling, DFe concentrations ranged between 1.2–3.9 nM. These high values result from inputs from the continental margin and are likely maintained by anoxic conditions in the water corresponding to the Oxygen Minimum Zone (OMZ. In subsurface waters near the Marquesas, that were also associated with the extension of the OMZ, DFe concentrations varied between 0.15–0.41 nM. Vertical transport of this water by mesoscale activity eastward of the archipelago may explain the dissymmetric east-west distribution of chlorophyll-a evidenced by satellite images. Using the new tracer Fe*=DFe−rFe:P (PO43− we show that DFe was in deficit compared to PO43− resulting from the remineralisation of organic matter. This suggests that the Marquesas islands and the surrounding plateau are not a significant source of DFe. In the gyre, DFe concentrations in the upper 350 m water column were around 0.1 nM and the ferricline was located well below the nitracline. These low concentrations reflect the low input of DFe from the atmosphere, from the ventilation of the upper thermocline with water containing low DFe, and from the low biological activity within this ultra oligotrophic gyre.

  8. Quaternary paleoceanographic reconstruction of Eastern Equatorial Pacific:planktic foraminiferal evidence

    Science.gov (United States)

    Mallick, Kirtiranjan; Sinha, Devesh K.; Singh, Ashutosh K.

    2016-04-01

    The Eastern Equatorial Pacific (EEP) is quite unique in its oceanographic set up and exhibits considerable variations on shorter to longer time scales. The region encounters intense upwelling caused by the Peru Current. The EEP show a strong ocean-atmosphere coupling, which is manifested in form of events like (El Nino Southern Oscillations (ENSO) that affects the global climate. The present work is based on planktic foraminiferal census data from the ODP Hole 846B, situated at 3°S latitude near the Galapagos spreading centre in the EEP, for paleoceanographic reconstructions for the Quaternary Period. Four species which show significant fluctuations in the relative abundance are Globigerinoides ruber (mixed layer and oligotrophic species), Neogloboquadrina dutertrei (fertility indicator and thermocline dweller),Globigerina bulloides (upwelling indicator) and Globorotalia inflata (temperate species). Results of the analyses of the census count of the planktic foraminifera indicate the overall dominance of the shallow water thermocline species N. dutertrei, suggesting the prevalence of the robust EEP Cold tongue during the Quaternary. The increase in the relative abundance of Gs.ruber marks seven planktic foraminiferal events (2.52Ma to 0.5Ma) of reduced strength of the cold tongue along the EEP. These intervals are concomitant with spreading and encroachment of warm water from the Western Pacific suggesting El Nino like conditions due to reduced strength of trade winds. Seven planktic foraminiferal events (2.42Ma to 0.20Ma) show prominent increase in the relative abundance of Gg.bulloides indicating advection of nutrient rich waters due to enhanced coastal upwelling. Invasion of the temperate species Globorotalia inflata is indicated by its abundance reaching up to 20 percent of the total assemblage at 3°S occur during ~ 2.07 Ma, 1.32 Ma and 1.05 Ma. The unusual occurrence of the cold water temperate species indicates the expansion of southern polar front which

  9. Late Holocene Sea Surface Temperature Trends in the Eastern Tropical Pacific

    Science.gov (United States)

    Rustic, G. T.; Koutavas, A.; Marchitto, T. M., Jr.

    2015-12-01

    The Eastern Tropical Pacific (ETP) is a highly dynamic ocean region capable of exerting influencing on global climate as illustrated by the El Niño-Southern Oscillation (ENSO). The sea surface temperature (SST) history of this region in past millennia is poorly constrained due to the lack of in situ records with appropriate resolution. Here we present a ~2700 year sub-centennially resolved SST reconstruction from Mg/Ca ratios of the planktonic foraminifer Globigerinoides ruber from Galápagos sediments. The ETP SST record exhibits a long-term cooling trend of over 0.2°C/ky that is similar to Northern Hemisphere multi-proxy temperature trends suggesting a common origin, likely due to insolation forcing. The ETP remains in-phase with Northern Hemisphere climate records through the warm Roman Climate Optimum (~0-400CE), cooler Dark Ages Cold Period (~450-850CE), and through the peak warming of the Medieval Climate Anomaly (900-1150 CE) when SST is within error of modern. Following peak MCA, the ETP cooled rapidly and then rebounded at ~1500 CE during the coldest portion of the Little Ice Age. Overall the data suggest an out-of-phase relationship during much of the last millennium, which we attribute to dynamical adjustments consistent with the "dynamical ocean thermostat" mechanism. Further evidence for these dynamical adjustments comes from reconstructions of the east-west zonal SST gradient using existing Mg/Ca SST reconstructions from the western Pacific warm pool. The last millennium has been the most dynamic period over the past 2700 years, with significant (~1 °C) SST variability in the ETP and modulation of the zonal gradient. A combination of dynamical and thermodynamic mechanisms are invoked to explain the region's complex SST history.

  10. Thermal adaptation of cytoplasmic malate dehydrogenases of eastern Pacific barracuda (Sphyraena spp): the role of differential isoenzyme expression

    Science.gov (United States)

    Lin; Somero

    1995-01-01

    Kinetic properties, electrophoretic patterns and thermal stabilities of cytoplasmic malate dehydrogenases (cMDHs) were compared in Eastern Pacific barracuda (Sphyraena spp) from different latitudes. All tissues of the tropical species S. ensis contained only a single, thermostable form of cMDH. Subtropical (S. lucasana) as well as north (S. argentea) and south (S. idiastes) temperate barracuda contained both thermostable and thermolabile cMDHs, the pattern characteristic of most teleosts. Kinetic studies using unfractioned cMDHs showed that the apparent Michaelis­Menten constant (Km) of cofactor (NADH) increased with temperature, but at the physiological temperatures of the four species, Km of NADH was conserved within a narrow range (20­23 µmol l-1). Thermostable and thermolabile cMDHs were chromatographically separated and compared. Thermolabile cMDHs had higher Km values for NADH at all measurement temperatures than did thermostable cMDHs. Thermolabile cMDHs isolated from congeneric barracuda exhibited similar kinetic properties (Km versus temperature, optimal pH, optimal substrate and cofactor concentrations). Thermostable cMDHs, likewise, were similar among the barracuda. Conservation of Km in the differently thermally adapted barracudas is, therefore, apparently due to adjustments in the ratio of expression of the thermostable and thermolabile isoforms, rather than to temperature-adaptive differences among orthologous homologues, as is commonly found for enzymes encoded by a single gene locus. The effects of temperature on the Km of NADH for isolated thermostable and thermolabile cMDHs of a eurythermal goby, Gillichthys mirabilis, however, were consistent with adaptive change in orthologous homologues of cMDH. The selective basis for the absence of thermolabile cMDH in warm-adapted ectotherms, mammals and birds is discussed.

  11. Limited-are a modelling of stratocumulus over South-Eastern Pacific

    Directory of Open Access Journals (Sweden)

    M. Andrejczuk

    2012-04-01

    Full Text Available This paper presents application of the Weather Research and Forecasting (WRF model to limited-area modeling of atmospheric processes over the subtropical south-eastern Pacific, with the emphasis on the stratocumulus-topped boundary layer. The simulations cover a domain from the VAMOS (Variability of the American Monsoon Systems Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx field project conducted in the subtropical south-eastern Pacific in October and November 2008. We focus on a day where the UK's BAe-146 research aircraft encountered Pockets of Open Cells (POCs at the very western edge of its flight track, rather than on the entire campaign as investigated in previous limited-area modeling studies. Model results are compared to aircraft observations with the main conclusion that the simulated stratocumulus-topped boundary layer is significantly too shallow. This appears to be a combination of an already too shallow boundary layer in the dataset used to provide initial and lateral boundary conditions, and the inability of the WRF model to increase the boundary-layer height. Several sensitivity simulations, applying different subgrid-scale parameterizations available in the model, a larger computational domain and longer simulations, as well as a different dataset providing initial and lateral boundary conditions were all tried to improve the simulation. These changes appeared to have a rather small effect on the results. The model does simulate the formation of mesoscale cloud-free regions that one might consider similar to Pockets of Open Cells observed in nature. However, formation of these regions does not seem to be related to drizzle-induced transition from open- to closed-cell circulations as simulated by LES models. Instead, the cloud-free regions appear to result from mesoscale variations of the lower-tropspheric vertical velocity. Areas of negative vertical velocity with minima (a few cm s−1 near the

  12. Anisotropy from SKS splitting across the Pacific-North America plate boundary offshore southern California

    Science.gov (United States)

    Ramsay, Joseph; Kohler, Monica D.; Davis, Paul M.; Wang, Xinguo; Holt, William; Weeraratne, Dayanthie S.

    2016-10-01

    SKS arrivals from ocean bottom seismometer (OBS) data from an offshore southern California deployment are analysed for shear wave splitting. The project involved 34 OBSs deployed for 12 months in a region extending up to 500 km west of the coastline into the oceanic Pacific plate. The measurement process consisted of removing the effects of anisotropy using a range of values for splitting fast directions and delay times to minimize energy along the transverse seismometer axis. Computed splitting parameters are unexpectedly similar to onland parameters, exhibiting WSW-ENE fast polarization directions and delays between 0.8 and 1.8 s, even for oceanic plate sites. This is the first SKS splitting study to extend across the entire boundary between the North America and Pacific plates, into the oceanic part of the Pacific plate. The splitting results show that the fast direction of anisotropy on the Pacific plate does not align with absolute plate motion (APM), and they extend the trend of anisotropy in southern California an additional 500 km west, well onto the oceanic Pacific plate. We model the finite strain and anisotropy within the asthenosphere associated with density-buoyancy driven mantle flow and the effects of APM. In the absence of plate motion effects, such buoyancy driven mantle flow would be NE-directed beneath the Pacific plate observations. The best-fit patterns of mantle flow are inferred from the tomography-based models that show primary influences from foundering higher-density zones associated with the history of subduction beneath North America. The new offshore SKS measurements, when combined with measurements onshore within the plate boundary zone, indicate that dramatic lateral variations in density-driven upper-mantle flow are required from offshore California into the plate boundary zone in California and western Basin and Range.

  13. Temperature profile data from BATHYTHERMOGRAPH (XBT) from LEXA MAERSK and other platforms in the eastern Pacific Ocean and southern Atlantic Ocean: 19880526 to 19890911 (NODC Accession 9000078)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The water depth and temperature data was collected from ships such as Lexa Maersk and 14 other ships. The data was collected from Eastern Pacific Ocean and Southern...

  14. AFSC/RACE/FBEP/Hurst: Distributional patterns of 0-group Pacific cod (Gadus macrocephalus) in the eastern Bering Sea under variable recruitment and thermal conditions

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset is from a study that analyzed the late summer distribution of juvenile Pacific cod in the eastern Bering Sea for 6 cohorts (2004-2009), based on catches...

  15. Special issue on the advances in understanding of the North Pacific subtropical front ecosystem

    Science.gov (United States)

    McKinnell, Skip; Seki, Michael P.; Ichii, Taro

    2017-01-01

    Subtropical, oligotrophic oceanic gyres are the largest marine ecosystems in the world. They provide important habitat for many higher trophic level species of fish, squid, seabirds, and marine mammals, with some taxa undergoing extensive seasonal migrations between the subtropical frontal region and summer feeding grounds in the subarctic. Knowledge of the structure, variability, and trends of these regions has developed slowly because of their immense size, remote location, and cost of sampling. The first consolidation of the general understanding of the physical nature of the subtropical North Pacific Ocean (and subarctic transition) was published 25 years ago (Roden, 1991) with important information on its relationship to biota added by the now defunct International North Pacific Fisheries Commission (INPFC, 1992; Ito et al., 1993). At that time, a research imperative had arisen from a need by governments to understand the effects of large-scale pelagic driftnet fishing on marine ecosystems (Wetherall, 1991).

  16. Interannual variability and future projection of summertime ocean wave heights in the western North Pacific

    Directory of Open Access Journals (Sweden)

    W. Sasaki

    2006-10-01

    Full Text Available A 70-yr (from 1985–1995 to 2055–2065 change of decadal mean summertime extreme significant wave heights (SWH in the western North Pacific under CO2-induced global warming condition is projected. For this purpose, possible atmospheric fields under future global warming are derived from 10-yr time-slice experiments using a T106 AGCM. The future changes of SWH are assessed by an empirical approach, where possible changes of SWH are estimated using a linear regression model which shows an empirical relationship between SWH anomalies and an eastward shift of the monsoon trough. It is projected that SWH increases by up to ~0.4 m over a wide area of the western North Pacific.

  17. Data-driven prediction strategies for low-frequency patterns of North Pacific climate variability

    CERN Document Server

    Comeau, Darin; Giannakis, Dimitrios; Majda, Andrew J

    2015-01-01

    The North Pacific exhibits patterns of low-frequency variability on the intra-annual to decadal time scales, which manifest themselves in both model data and the observational record, and prediction of such low-frequency modes of variability is of great interest to the community. While parametric models, such as stationary and non-stationary autoregressive models, possibly including external factors, may perform well in a data-fitting setting, they may perform poorly in a prediction setting. Ensemble analog forecasting, which relies on the historical record to provide estimates of the future based on past trajectories of those states similar to the initial state of interest, provides a promising, nonparametric approach to forecasting that makes no assumptions on the underlying dynamics or its statistics. We apply such forecasting to low-frequency modes of variability for the North Pacific sea surface temperature and sea ice concentration fields extracted through Nonlinear Laplacian Spectral Analysis. We find ...

  18. Tropic dynamics of albatrosses associated with squid and large-mesh driftnet fisheries in the North Pacific Ocean

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Diets of Laysan (LAA) and Black-footed albatrosses (BFA) killed in squid and large-mesh driftnets in the transitional zone of the North Pacific Ocean were...

  19. Western North Pacific Tropical Cyclone Formation and Structure Change in TCS08

    Science.gov (United States)

    2013-09-30

    field program . Davos Atmosphere and Cryosphere Assembly DACA -13. July 2013. Harr, P. A., H. M. Archambault, and C.-C. Wu, 2013: Air-ocean...TITLE AND SUBTITLE Western North Pacific Tropical Cyclone Formation and Structure Change in TCS08 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ...Tropical Cyclone Structure-2008 (TCS-08) program and the Impact of Typhoons on the Ocean (ITOP) program resulted in direct observations of the

  20. Relationships Between Global Warming and Tropical Cyclone Activity in the Western North Pacific

    Science.gov (United States)

    2007-09-01

    In this work, we investigate the relationships between global warming and tropical cyclone activity in the Western North Pacific (WNP). Our...hypothesis is that global warming impacts on TC activity occur through changes in the large scale environmental factors (LSEFs) known to be important in...averages. Using a least squares fit, we identify global warming signals in both the SST and vertical wind shear data across the WNP. These signals vary

  1. Convection and Easterly Wave Structure Observed in the Eastern Pacific Warm-Pool during EPIC-2001

    Science.gov (United States)

    Peterson, Walter A.; Cifelli, R.; Boccippio, D.; Rutledge, S. A.; Fairall, C. W.; Arnold, James E. (Technical Monitor)

    2002-01-01

    During September-October 2001, the East Pacific Investigation of Climate Processes in the Coupled Ocean-Atmosphere System (EPIC-2001) ITCZ field campaign focused on studies of deep convection in the warm-pool region of the East Pacific. In addition to the TAO mooring array, observational platforms deployed during the field phase included the NOAA ship RN Ronald H. Brown, the NSF ship RN Horizon, and the NOAA P-3 and NCAR C-130 aircraft. This study combines C-band Doppler radar, rawinsonde, and surface heat flux data collected aboard the RN Brown to describe ITCZ convective structure and rainfall statistics in the eastern Pacific as a function of 3-5 day easterly wave phase. Three distinct easterly wave passages occurred during EPIC-2001. Wind and thermodynamic data reveal that the wave trough axes exhibited positively correlated U and V winds and a slight westward phase tilt with height. A relatively strong (weak) northeasterly deep tropospheric shear followed the trough (ridge) axis. Temperature and humidity perturbations exhibited mid-to upper level cooling (warming) and drying (moistening) in the northerly (trough and southerly) phase. At low levels warming (cooling) occurred in the northerly (southerly) phase with little change in the relative humidity, though mixed layer mixing ratios were larger during the northerly phase. When composited, radar, sounding, lightning and surface heat flux observations suggest the following systematic behavior as a function of wave phase: approximately zero to one quarter wavelength ahead of (behind) the wave trough in northerly (southerly) flow, larger (smaller) CAPE, lower (higher) CIN, weaker (stronger) tropospheric shear, higher (lower) conditional mean rain rates, higher (lower) lightning flash densities, and more (less) robust convective vertical structure occurred. Latent and sensible heat fluxes reached a minimum in the northerly phase and then increased through the trough, reaching a peak during the ridge phase

  2. Strong Input and Removal of Rare Earth Elements (REEs) Affect Dissolved Nd Isotope Composition of Seawater in the Panama Basin and the Eastern Equatorial Pacific

    Science.gov (United States)

    Frank, M.; Bosse, L. M.; Grasse, P.; Pahnke, K.; Hathorne, E. C.

    2014-12-01

    The distributions of dissolved REEs and Nd isotopes are controlled by inputs from land and water mass mixing. We present new data from the Panama Basin in the Eastern Equatorial Pacific (EEP) extending previous studies in the frame of the German SFB 754 project. The samples were taken following GEOTRACES protocols along a section from close to the Panamanian coast into the deep Panama Basin during FS Meteor cruise M90 in October/November 2012. Elevated Nd concentrations near 13 pmol/kg are found at the surface, which rapidly decrease to a subsurface minimum of 8 pmol/kg near 100m depth and then increase with water depth reaching maximum values of 18 pmol/kg at 3000 m water depth. However, these deep water concentrations are more than a factor of 2 lower than observed for North Pacific Deep Water (NPDW), which is the prevailing Pacific deep water mass at the sampling locations. All the REEs are depleted compared to NPDW suggesting that efficient uptake and scavenging dominate compared to release from remineralized particles. The surface waters show the most radiogenic Nd isotope values (ɛNd = +4.3) so far obtained globally. In combination with the Nd concentration maxima at the surface this suggests riverine dissolved and fine grained particulate inputs from southern Panama and Colombia where highly radiogenic volcanic rocks are exposed. Elevated ɛNd values above -1 in the entire water column are more radiogenic than in NPDW in the Central Pacific and in waters further south in the EEP, which confirms that release of REEs from the sinking volcanogenic material affects the entire water column. These data clearly document that significant inputs from land combined with efficient scavenging and removal in surface and deep waters control the distribution of REEs and Nd isotopes in the Panama Basin and the adjacent EEP (Grasse et al., 2012), which also has important implications for the distribution of other trace metals.

  3. Physical and underway data collected aboard the ATLANTIS during cruise AT15-63 in the North Pacific Ocean and South Pacific Ocean from 2010-03-15 to 2010-04-14 (NODC Accession 0103918)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC accession 0103918 includes physical and underway data collected aboard the ATLANTIS during cruise AT15-63 in the North Pacific Ocean and South Pacific Ocean...

  4. Physical and underway data collected aboard the ATLANTIS during cruise AT15-42 in the North Pacific Ocean and South Pacific Ocean from 2009-01-09 to 2009-02-02 (NODC Accession 0103871)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC accession 0103871 includes physical and underway data collected aboard the ATLANTIS during cruise AT15-42 in the North Pacific Ocean and South Pacific Ocean...

  5. Chemical, optical and other data collected aboard the MELVILLE during cruise MV1105 in the North Pacific Ocean and South Pacific Ocean from 2011-04-29 to 2011-05-28 (NODC Accession 0116958)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0116958 includes chemical, optical and other data collected aboard the MELVILLE during cruise MV1105 in the North Pacific Ocean and South Pacific...

  6. Physical and underway data collected aboard the MELVILLE during cruise MV1007 in the North Pacific Ocean and South Pacific Ocean from 2010-05-17 to 2010-06-16 (NODC Accession 0089615)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC accession 0089615 includes physical and underway data collected aboard the MELVILLE during cruise MV1007 in the North Pacific Ocean and South Pacific Ocean from...

  7. Physical and underway data collected aboard the KNORR during cruise KN195-03 in the North Pacific Ocean and South Pacific Ocean from 2009-01-12 to 2009-02-23 (NODC Accession 0104265)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC accession 0104265 includes physical and underway data collected aboard the KNORR during cruise KN195-03 in the North Pacific Ocean and South Pacific Ocean from...

  8. Physical and underway data collected aboard the ROGER REVELLE during cruise AMAT02RR in the North Pacific Ocean and South Pacific Ocean from 2005-09-03 to 2006-03-03 (NCEI Accession 0155592)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0155592 includes physical and underway data collected aboard the ROGER REVELLE during cruise AMAT02RR in the North Pacific Ocean and South Pacific...

  9. Physical and underway data collected aboard the ROGER REVELLE during cruise AMAT03RR in the North Pacific Ocean and South Pacific Ocean from 2006-03-07 to 2006-04-13 (NCEI Accession 0155593)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0155593 includes physical and underway data collected aboard the ROGER REVELLE during cruise AMAT03RR in the North Pacific Ocean and South Pacific...

  10. Lowermost mantle anisotropy near the eastern edge of the Pacific LLSVP: constraints from SKS-SKKS splitting intensity measurements

    Science.gov (United States)

    Deng, Jie; Long, Maureen D.; Creasy, Neala; Wagner, Lara; Beck, Susan; Zandt, George; Tavera, Hernando; Minaya, Estela

    2017-08-01

    Seismic anisotropy has been documented in many portions of the lowermost mantle, with particularly strong anisotropy thought to be present along the edges of large low shear velocity provinces (LLSVPs). The region surrounding the Pacific LLSVP, however, has not yet been studied extensively in terms of its anisotropic structure. In this study, we use seismic data from southern Peru, northern Bolivia and Easter Island to probe lowermost mantle anisotropy beneath the eastern Pacific Ocean, mostly relying on data from the Peru Lithosphere and Slab Experiment and Central Andean Uplift and Geodynamics of High Topography experiments. Differential shear wave splitting measurements from phases that have similar ray paths in the upper mantle but different ray paths in the lowermost mantle, such as SKS and SKKS, are used to constrain anisotropy in D″. We measured splitting for 215 same station-event SKS-SKKS pairs that sample the eastern Pacific LLSVP at the base of the mantle. We used measurements of splitting intensity(SI), a measure of the amount of energy on the transverse component, to objectively and quantitatively analyse any discrepancies between SKS and SKKS phases. While the overall splitting signal is dominated by the upper-mantle anisotropy, a minority of SKS-SKKS pairs (˜10 per cent) exhibit strongly discrepant splitting between the phases (i.e. the waveforms require a difference in SI of at least 0.4), indicating a likely contribution from lowermost mantle anisotropy. In order to enhance lower mantle signals, we also stacked waveforms within individual subregions and applied a waveform differencing technique to isolate the signal from the lowermost mantle. Our stacking procedure yields evidence for substantial splitting due to lowermost mantle anisotropy only for a specific region that likely straddles the edge of Pacific LLSVP. Our observations are consistent with the localization of deformation and anisotropy near the eastern boundary of the Pacific LLSVP

  11. High-resolution reconstructions of Pacific-North America plate motion: 20 Ma to present

    Science.gov (United States)

    DeMets, C.; Merkouriev, S.

    2016-11-01

    We present new rotations that describe the relative positions and velocities of the Pacific and North America plates at 22 times during the past 19.7 Myr, offering ≈1-Myr temporal resolution for studies of the geotectonic evolution of western North America and other plate boundary locations. Derived from ≈18 000 magnetic reversal, fracture zone and transform fault identifications from the Pacific-Antarctic-Nubia-North America plate circuit and the velocities of 935 GPS sites on the Pacific and North America plates, the new rotations and GPS-derived angular velocity indicate that the rate of motion between the two plates increased by ≈70 per cent from 19.7 to 9±1 Ma, but changed by less than 2 per cent since 8 Ma and even less since 4.2 Ma. The rotations further suggest that the relative plate direction has rotated clockwise for most of the past 20 Myr, with a possible hiatus from 9 to 5 Ma. This conflicts with previously reported evidence for a significant clockwise change in the plate direction at ≈8-6 Ma. Our new rotations indicate that Pacific plate motion became obliquely convergent with respect to the San Andreas Fault of central California at 5.2-4.2 Ma, in agreement with geological evidence for a Pliocene onset of folding and faulting in central California. Our reconstruction of the northern Gulf of California at 6.3 Ma differs by only 15-30 km from structurally derived reconstructions after including 3-4 km Myr-1 of geodetically measured slip between the Baja California Peninsula and Pacific plate. This implies an approximate 15-30 km upper bound for plate non-rigidity integrated around the global circuit at 6.3 Ma. A much larger 200±54 km discrepancy between our reconstruction of the northern Gulf of California at 12 Ma and that estimated from structural and marine geophysical observations suggests that faults in northwestern Mexico or possibly west of the Baja California Peninsula accommodated large amounts of obliquely divergent dextral shear

  12. Aerosols impact on the multi-decadal SST variability simulation over the North Pacific

    Science.gov (United States)

    Boo, Kyung-On; Booth, Ben; Byun, Young-Hwa; Cho, ChunHo; Lee, Johan; Park, Soo-Hyun; Shim, Sung-Bo; Park, Sung-Bin

    2013-04-01

    Aerosol emission by the anthropogenic source has increased in the 20th century and the effects on climate have received much attention for understanding of historical climate change and variability. Aerosols contribute to change solar radiation at the surface directly and indirectly enhance radiative effect through cloud properties changes, altering surface climate and large-scale atmospheric circulation as well. Recently Oldenborgh et al. [2012] , Chikamoto et al. [2012] and Wang et al.[2012] showed the Pacific decadal scale variability is able to be affected by the aerosols. Since climate response in global warming is modulated by decadal variability and the Asian monsoon circulation changes are known to be affected by anthropogenic aerosols [Lau et al., 2006; Ramana et al., 2010], aerosol impact over the Pacific needs to be studied. Both effects by natural and anthropogenic emissions are important. To simulate the North Atlantic climate variability, aerosol forcing is important [Mann and Emanuel, 2006; Oldenborgh et al., 2012]. In particular, it is known to be better represented when indirect effect by anthropogenic emitted aerosols is considered [Booth et al, 2011]. Therefore, considering previous studies, this study investigates aerosol effect with indirect effect by anthropogenic aerosol emission over the Pacific. In this study, comparison between historical run and fixed aerosol experiments using HadGEM2-AO shows that multidecadal variability in historical run is closer to the observed ERSST variability over the North Pacific. In detrended SST anomalies, warming and cooling in the period of 1925-1960 and 1965-1990 are reproduced in aerosol forced historical simulation. The climate variability is partly related by the shortwave changes in response to aerosols emission. There is cooling effect, directly. Here, we are interested in indirect cloud property changes and the Pacific SST variability is investigated using previous results [Williams et al., 2001

  13. Stranding survey as a framework to investigate rare cetacean records of the north and north-eastern Brazilian coasts

    Directory of Open Access Journals (Sweden)

    Alexandra Fernandes Costa

    2017-08-01

    Full Text Available Marine mammal stranding events are used as an important tool for understanding cetacean biology worldwide. Nonetheless, there are vast gaps of knowledge to be filled in for a wide range of species. Reputable information is required regarding species from large baleen whales to sperm and beaked whales, as well as pelagic dolphins. This paper describes new cetacean records from north and north-eastern Brazil, which are both the least surveyed areas regarding aquatic mammals. Regular beach surveys were conducted to recover cetacean carcasses along the coast of Pará beginning November 2005. At the coasts of the Maranhão and Piauí states, the surveys were conducted between 2003 and 2013. From 2003 to 2014, 34 strandings of cetaceans were registered. The study provides four additional species records’ in the area based on strandings (Balaenoptera borealis, Balaenoptera physalus, Peponocephala electra, and Pseudorca crassidens. A mass stranding of Guiana dolphins (Sotalia guianensis, N = 12, the most common species for the region, was reported for the first time. The records presented herein are of special concern, since they expand the knowledge on cetaceans from the Brazilian coast. In addition, this study conducted an analysis to verify the similarity between cetacean compositions described for north and north-eastern Brazil and the southern Caribbean region. The results showed a high similarity between these regions, proving the connection with the Caribbean cetacean fauna.

  14. APL-UW Deep Water Propagation: Philippine Sea Signal Physics and North Pacific Ambient Noise and NPANL Support

    Science.gov (United States)

    2014-09-30

    APL-UW Deep Water Propagation: Philippine Sea Signal Physics and North Pacific Ambient Noise and NPANL Support Rex K. Andrew Principal...signals evolve during propagation through a dynamically-varying deep ocean, and how the oceanic ambient noise field varies throughout deep ocean...specifically the Philippine Sea. The second objective is to continue an 18-year long experiment utilizing the North Pacific Ambient Noise Laboratory to

  15. Mt. Logan Ice Core Record of North Pacific Holocene Climate Variability

    Science.gov (United States)

    Osterberg, E. C.; Mayewski, P. A.; Fisher, D. A.; Kreutz, K. J.; Handley, M. J.; Sneed, S. B.

    2006-12-01

    A >12,000 year-long, continuous, high-resolution (sub-annual to multi-decadal) ice core record from the summit plateau (5300 m asl) of Mt. Logan, Yukon, Canada, reveals large, abrupt fluctuations in North Pacific climate throughout the Holocene with a 1-2 ky periodicity. Co-registered major ion, trace element and stable isotope time series reveal a strong inverse relationship between precipitation δ18O and atmospheric seasalt and dust concentrations over multi-decadal to millennial periods (rMt. Logan represent changes in moisture source region between dominantly cold North Pacific waters (more zonal circulation; enriched stable isotope values) and warmer subtropical waters (more meridional circulation; depleted stable isotope values). Consequently, Holocene millennial-scale stable isotope fluctuations in the Mt. Logan core have a larger amplitude (6-9‰ for δ18O) than those found in Greenland and Canadian Arctic ice core records (e.g. 2-3‰ for GISP2 δ18O). Over the instrumental period (1948-1998), higher Mt. Logan dust concentrations are strongly associated with enhanced springtime cyclonic activity over East Asian desert source regions (rMt. Logan seasalt aerosol concentrations are related to the wintertime strength of the Aleutian Low pressure center (r<-0.45, p<0.001). We use these calibrated proxy relationships to propose a conceptual model of North Pacific atmospheric circulation during the Holocene.

  16. The Moisture Structure of ISO in Western North Pacific Revealed by AIRS

    Institute of Scientific and Technical Information of China (English)

    TAO Li; FU Xiouhua; WANG Bin

    2009-01-01

    Using the humidity profiles from the Atmospheric Infrared Sounder (AIRS) dataset, rainfall from the Tropical Rainfall Measuring Mission (TRMM) Global Precipitation Index (GPI), and surface winds from QuickSCAT (QSCAT) as well as SST from the Advanced Microwave Scanning Radiometer for NASA's Earth Observing System (AMSR_E), we analyzed the structure of summer intraseasonal oscillation (ISO) over the western North Pacific region in 2003-2004. We find that the signal of 20-90-day oscillations in the western North Pacific originates from the equatorial Indian Ocean, and propagates eastward to Philippine Sea and then moves northwestward to South China. The AIRS humidity data reveal that the boundary-layer moisture leads the mid-troposphere moisture during the ISO propagation. The positive SST anomaly may play an important role to moistening the boundary-layer, which preconditions the ISO propagation. Therefore, the intraseasonal SST anomaly could positively feed back to the atmosphere through moistening the boundary-layer, destabilizing the troposphere, and contributing to the northwestward propagation of the ISO in western North Pacific. On the other hand, the salient feature that the boundary-layer moisture anomaly leads mid-troposphere moisture does not exist in ECMWF/TOGA analysis.

  17. Hydroclimate variability of the South American Monsoon System during the last 1600 yr inferred from speleothem isotope records of the north-eastern Andes foothills in Peru

    Directory of Open Access Journals (Sweden)

    J. Apaéstegui

    2014-02-01

    Full Text Available In this paper we explore a speleothem δ18O record from Palestina Cave, North Eastern Peru, at a site on the eastern side of the Andes cordillera, upper Amazon Basin, interpreted as a proxy for South America Summer Monsoon (SASM intensity. This record allows reconstructing SASM activity with 5 yr time resolution over the last 1600 yr, spanning two major periods of climate variability: the Medieval Climate Anomaly (MCA; 900–1200 AD and Little Ice Age (LIA 1400–1850 AD recognized as periods of decrease and increase SASM activity respectively. Time series and wavelet analyses reveal decadal to multidecadal frequencies. Our results suggest that Atlantic Multidecadal Oscillation mode (AMO plays an important role for SASM modulation on multidecadal scale (~65 yr, especially over dry periods such as observed during MCA. Frequencies of 8 and 25 yr simultaneously with multidecadal signal (65 yr are found over the LIA. and suggest that those modes could be related to North Atlantic Oscillation (NAO and Interdecadal Pacific Oscillation mode (IPO. Comparison with other South American Paleoprecipitation records shows that the Atlantic and Pacific decadal to multidecadal variability and their teleconnections play an important role in the intensity and the regional patterns of rainfall distribution during the last 1600 yr.

  18. Roles of Multi-Scale Disturbances over the Tropical North Pacific in the Turnabout of 1997-98 El Ni(n)o

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zuqiang; ZHANG Renhe; Song YANG

    2007-01-01

    The space-time features of major vorticity disturbances over the western North Pacific during the 1997-98 El Ni(n)o ranked as one of the strongest events on record was investigated in this study. We distinguished the different roles that these disturbances had on different timescales in causing the reversal or turnabout of the El Ni(n)o event. Remarkable differences in the various disturbances of synoptic, intraseasonal, and interannual timescales were found in the time evolution, propagation, and in their contributions to the changes in nearequatorial zonal flow, which was crucial to the demise of the warm sea surface temperature anomalies in the central-eastern Pacific. It is hypothesized that the westward-traveling synoptic and intraseasonal oscillations in the western North Pacific might be considered as a self-provided negative feedback from the El Ni(n)o and played an additional role in its reversal in comparison with other interannual internal and external forcings.In this case, the off-equatorial synoptic and intraseaonal fluctuations served as a stochastic forcing for the tropical ocean and gave rise to the aperiodicity or irregularity of the El Ni(n)o-Southern Oscillation.

  19. Microbes adapt to iron scarcity through siderophore production across the eastern tropical Pacific

    Science.gov (United States)

    Repeta, D.; Boiteau, R.; Mende, D. R.; DeLong, E.

    2016-02-01

    Iron regulates microbial growth and carbon fixation rates in vast regions of the ocean characterized by high nutrient and low chlorophyll (HNLC) concentrations. As competition for bioavailable iron in HNLC regions intensifies, microbial communities face tremendous selective pressure to develop efficient uptake and utilization strategies that access the strong organic ligands controlling iron bioavailability in these areas. Using liquid chromatography mass spectrometry, we found 27 unique iron complexes in surface waters sampled across the GEOTRACES eastern tropical Pacific zonal cruise track, with a clear trend in the abundance of different ligands across nutrient regimes. We identified siderophores, compounds produced by microbes under iron stress to facilitate iron uptake, as important components of iron ligands. Siderophore composition varied dramatically across the region, reflecting adaptive microbial strategies for acquiring iron. Concentrations of amphibactins, amphiphilic siderophores with cell membrane affinity, were low in coastal waters, but reached 9pM in HNLC waters, while ferrioxamine concentrations were higher in coastal and oligotrophic regions (1-2pM). These spatial changes in siderophore distributions represents adaptations used by marine microbes to acquire iron under different ecological conditions. To infer the potential ocean-wide contribution of amphibactins to microbial iron acquisition, we investigated the distribution of amphibactin synthesis genes in the recently published TARA Oceans metagenomic catalogue. We found amphibactin synthesis genes were present in other major iron-starved regions, suggesting that adaptations involving siderophore utilization likely impact global marine ecosystem composition and productivity.

  20. Nitrous oxide production in the eastern tropical South Pacific oxygen minimum zone

    Science.gov (United States)

    Ji, Qixing; Altabet, Mark; Arevalo-Martinez, Damian; Bange, Hermann; Ma, Xiao; Marandino, Christa; Sun, Mingshuang; Grundle, Damian

    2017-04-01

    Nitrous oxide (N2O) is an important climate active trace gas that contributes to both atmospheric warming and ozone destruction, and the ocean is an important source of N2O to the atmosphere. Dissolved oxygen concentrations play an important role in regulating N2O production in the ocean, such that under low oxygen conditions major shifts in the predominant production pathways (i.e. nitrification vs. denitrification) can occur and the magnitude of production may increase substantially. To this end, major oceanic oxygen minimum zones (OMZs) are responsible for a disproportionately high amount of marine N2O production. During the October 2015 ASTRA-OMZ cruise to the eastern tropical South Pacific (ETSP), one of the three major oceanic OMZs, we measured a suite of N2O parameters which included N2O concentrations, N2O production, and natural abundance N2O isotope (i.e. del 15N and del 18O) and isotopomer (i.e. 15N site-preference) signatures. Based on the results from these measurements, our presentation will demonstrate how N2O production and the different production pathways change along the oxygen concentration gradients from the oxygenated surface waters through the oxygen minimum layer. Our data could better constrain the importance of the ETSP-OMZ as source of marine N2O. Results from this work will provide insights into how N2O cycling responds to ocean deoxygenation as a result of climate change.

  1. A revision of the genus Muricea Lamouroux, 1821 (Anthozoa, Octocorallia) in the eastern Pacific. Part II.

    Science.gov (United States)

    Breedy, Odalisca; Guzman, Hector M

    2016-01-01

    The species of the genus Muricea were mainly described from 1846 to 1870. After that very few contributions were published. Although the highest richness of Muricea species is in the eastern Pacific shallow waters, a comprehensive systematic study of the genus does not exist. Recently we started a taxonomic review of the genus in order to validate the status of four species previously included in the genus Eumuricea. Herein we present the second part of the Muricea revision dealing with the species-group characterised by shelf-like calyces instead of tubular-like calyces (the Muricea squarrosa-group). Original type material was morphologically analysed and illustrated using optical and scanning electron microscopy. Comparative character tables are provided for the genus. The taxonomic status of the species was analysed and established by designating lectotypes, alternatively by recognising a holotype by monotypy. We conclude that the genus Muricea comprises 20 valid species, including the previous four in the Muricea squarrosa-group. We propose 10 lectotypes, a new combination and three more species groups for the genus based on morphology: the Muricea fruticosa-group, Muricea plantaginea-group and Muricea austera-group.

  2. Gradients in Strong and Weak Organic Copper-Binding Ligands in the Eastern Tropical South Pacific

    Science.gov (United States)

    Ruacho, A.; Bundy, R.; Barbeau, K.; Parker, C.; Roshan, S.; Wu, J.

    2014-12-01

    Dissolved organic copper-binding ligands were examined on the U.S. GEOTRACES zonal transect in the Eastern Tropical South Pacific from Peru to Tahiti. All samples were measured using competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-ACSV), and a subset were analyzed using multiple competition strengths of the added ligand salicylaldoxime (1, 2.5, 5, 10, and 25 μM). Titration data was processed using newly available multiple analytical window data processing techniques, which unify the multiple window dataset as a whole. Multiple competition strengths of the added ligand enabled the detection of an additional weaker class of copper-binding ligand, compared to the two stronger ligand classes which have been measured previously in the open ocean. The strongest ligand class (L1) ranged in concentration from 1-10 nmol L-1 and had a conditional stability constant (logK) ranging from approximately 15.0-16.0. The weaker ligand classes (L2, and L3) were present in much higher concentrations even in surface waters, with concentrations ranging from 5-50 nmol L-1 and conditional stability constants ranging from 8.6-12.5. The elevated ligand concentrations, both in surface and deep waters, lead to extremely low concentrations of Cu2+ throughout the transect, possibly influencing important biogeochemical processes such as inducible iron acquisition by diatoms, and ammonium oxidation in the oxygen minimum zone.

  3. Copper Speciation Results From The U.S. GEOTRACES Eastern Tropical South Pacific Cruise

    Science.gov (United States)

    Ruacho, A.; Bundy, R.; Barbeau, K.; Parker, C.; Bruland, K. W.; Roshan, S.; Wu, J.

    2016-02-01

    Dissolved organic copper-binding ligands were examined on the U.S. GEOTRACES zonal transect in the Eastern Tropical South Pacific from Peru to Tahiti. All samples were measured using competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-ACSV), the bulk in duplicate titrations at a single analytical window (5 µM) using the added ligand salicylaldoxime (SA). A subset of samples were also analyzed using multiple competition strengths (1, 2.5, 5, 10, and 25 µM added SA), along with equilibration tests at each analytical window. Titration data was processed using newly available software for single and multiple analytical window data. Equilibration tests conducted at the various analytical windows showed no significant differences in ligand concentration and binding strength between overnight vs. 15-30 minute equilibration times. Samples analyzed at a single window reveal excess strong ligands in the coastal region over the oxygen minimum zone with a conditional stability constant (logK) around 14. Multiple competition strengths of the added ligand enabled the detection of up to three classes of copper-binding ligands, with conditional stability constants ranging from 8.6-16.0, and high concentrations of weaker ligands throughout the water column. The presence of strong copper-binding ligands across the transect led to low free copper concentrations, which can be limiting to some phytoplankton. Analysis is ongoing and this presentation will summarize the status of this unique data set.

  4. Halogens, OVOC and H2O Distributions over the Eastern Pacific Ocean during TORERO

    Science.gov (United States)

    Dix, B. K.; Apel, E. C.; Baidar, S.; Zondlo, M. A.; Volkamer, R.

    2013-12-01

    As part of the Tropical Ocean tRoposphere Exchange of Reactive halogen species and Oxygenated VOC (TORERO) field project 17 research flights were conducted with the NSF/NCAR GV aircraft over the Eastern Tropical Pacific Ocean (42S to 14N Lat.; 70W to 105W Long). Equipped with a combination of chemical in-situ sensors and remote sensing instruments, a broad spectrum of reactive halogen species, oxygenated hydrocarbons, and aerosols were measured over different ocean environments. Using optical remote sensing (airborne Multi Axis DOAS), we measured iodine monoxide (IO), bromine monoxide (BrO), glyoxal (CHOCHO) and water vapor among others. A newly developed parameterization method allowed us to directly convert the measured slant column densities into mixing ratios along the whole flight track. Atmospheric reactive halogen species and organic carbon are important, because they modify HOx radical abundances, influence the reactive chemistry and lifetime of climate active gases (e.g., ozone, methane, dimethyl sulfide), modify aerosol-cloud interactions and halogen radicals can also oxidize atmospheric mercury. Here we summarize and evaluate the spatial distribution of IO, BrO and glyoxal over the TORERO study area. For select case studies we present comparisons to halogen precursors and OVOCs measured in-situ by on-line mass spectrometry (trace organic gas analyzer). The correlation of remotely observed water vapor to in-situ measurements further allows us to conclude on the homogeneity of spatial scales covered by both remote and in-situ sensors.

  5. Lack of divergence in seed ecology of two Amphicarpaea (Fabaceae) species disjunct between eastern Asia and eastern North America.

    Science.gov (United States)

    Zhang, Keliang; Baskin, Jerry M; Baskin, Carol C; Yang, Xuejun; Huang, Zhenying

    2015-06-01

    Many congeneric species are disjunct between eastern Asia and eastern North America. No previous study has compared the seed biology of closely related disjunct taxa of legumes or of a diaspore-heteromorphic species. Our objective was to compare seed dormancy in two such sister species in the genus Amphicarpaea (Fabaceae). We investigated the ecology and ecophysiology of aerial and subterranean seeds of the amphicarpic species Amphicarpaea edgeworthii from China and compared the results to those published for its sister species A. bracteata from eastern North America. The seed coat of aerial seeds of A. edgeworthii is well developed, whereas the seed coat of subterranean seeds is not. Aerial seeds have combinational dormancy (physical dormancy [PY] + physiological dormancy [PD]) broken by scarification followed by cold stratification or by after-ripening and scarification; whereas subterranean seeds have PD broken by cold stratification. Aerial seeds formed a persistent soil seed bank, and subterranean seeds a transient soil seed bank. Aerial seeds of A. bracteata also have PY+PD and subterranean seeds PD. Subterranean seeds of both species are desiccation intolerant. Dormancy in neither aerial nor subterranean seeds of both species has diverged over geological time. Compared to subterranean seeds, aerial seeds of both species dispersed over longer distances. Seed dispersal ability and degree of dormancy of neither species fits the high-risk/low-risk (H-H/L-L) strategy found in many diaspore-dimorphic species. Rather, both species have an H-L/L-H strategy for these two life history traits. © 2015 Botanical Society of America, Inc.

  6. A research on consumer satisfaction and shopping patterns of households in the North Eastern Savo region

    OpenAIRE

    Taavitsainen, Ossi

    2015-01-01

    This Bachelor’s thesis deals with shopping patterns of consumers and their satisfaction with local supply of goods in the North Eastern Savo region in Finland. The thesis was conducted as a follow-up research to the original research made by a student of the University of Eastern Finland in 2009-2010. The theoretical part of the thesis consists of two main topics: purchase behavior of consumers and development of online shopping. The empirical part is based on a survey, conducted among consum...

  7. Mapping cumulative human impacts in the eastern North Sea

    DEFF Research Database (Denmark)

    Stock, A.; Andersen, Jesper; Heinänen, S.

    of the MSFD; and 3) to deepen the understanding of how errors in expert judgment affect the resulting cumulative human impact maps by means of Monte Carlo simulations. We combined existing data sets on the spatial distribution of 33 anthropogenic stressors (linked to the MSFD pressures) and 28 key habitats....... In contrast, the predicted impacts for much of the Norwegian EEZ and areas far offshore were lower. The Monte Carlo simulations confirmed earlier findings that mapping cumulative impacts is generally "robust", but also showed that specific combinations of errors can seriously change local and regional...... on marine ecosystems have only recently been developed. The aims of our study were: 1) to develop a map of cumulative human impacts for the Danish, Swedish, Norwegian and German parts of the Greater North Sea; 2) to adjust the existing methods for mapping cumulative human impacts to fit the requirements...

  8. Peat Formation on Minjerribah (North Stradbroke Island), subtropical eastern Australia

    Science.gov (United States)

    Moss, Patrick; Tibby, John; Barr, Cameron; Weerensena, Chagi; Gontz, Allen; Petherick, Lynda

    2016-04-01

    Minjerribah (North Stradbroke Island) is the second largest sand island in the world and contains extensive peat dominated wetlands, comprising ~20% of the total area of the island. These wetland systems include large areas of estuarine swamps [mainly mangrove forest (~16% of the island's wetland area)], freshwater swamps [both herb (~58% of the island's wetland area) and tree dominated (~20% of the island's wetland area)] and numerous lake systems [both perched and window lakes (~2% of the island's wetland area)]. This presentation will examine peat formation processes at four wetland sites: a late Holocene prograding beach system (Flinders Beach); a 150,000 year lacustrine system (Welsby Lagoon 1), as well as a late Holocene lacustrine/palustrine system (Welsby Lagoon 2); and a late Quaternary lacustrine/palustrine system (Tortoise Lagoon), as well as discussing broader environmental characteristics of Minjerribah's nationally and internationally important wetland systems.

  9. Denali Ice Core Record of North Pacific Hydroclimate, Temperature and Atmospheric Circulation over the Past Millennium

    Science.gov (United States)

    Osterberg, E. C.; Wake, C. P.; Kreutz, K. J.; Winski, D.; Ferris, D. G.; Introne, D.; Campbell, S.; Birkel, S. D.

    2015-12-01

    While tree ring and lake sediment core studies have revealed a great deal about North Pacific (e.g. Alaska) surface temperature variability over the past millennium, we do not have an equivalent understanding of North Pacific hydroclimate variability or temperatures at high elevations. A millennial-length precipitation proxy record is needed to place late 20th century Alaskan precipitation increases into longer context, and to evaluate hydroclimate changes during the Little Ice Age and Medieval Climate Anomaly. High-elevation summer temperature records would be valuable for understanding the sensitivity of Alaskan glaciers to past warm and cool periods. Here we present an overview of the new Denali Ice Core record collected from the summit plateau (4000 m a.s.l.) of Mt. Hunter (63° N, 151° W) in Denali National Park, Alaska. Two parallel ice cores were collected to bedrock (208 m in length) in May-June 2013, sampled using the Dartmouth continuous melter system, and analyzed for major ions, trace elements, particle concentration and size distribution, and stable isotope ratios at Dartmouth and the Universities of Maine and New Hampshire. The cores are dated using robust annual oscillations in dust elements, methanesulfonate, ammonium, and stable isotopes, and validated using major volcanic eruptions recorded as sulfate, chloride and heavy metal spikes, and the 1963 nuclear weapons testing 137Cs spike. Preliminary analyses indicate a significant increase in both summer temperature and annual accumulation over the 20th century, and significant relationships with major ocean-atmospheric modes including the Pacific Decadal Oscillation. We compare the new Denali record to the Eclipse Icefield and Mt. Logan ice core records and develop composite records of North Pacific hydroclimate and atmospheric circulation variability over the past millennium.

  10. On the unstable ENSO-Western North Pacific Monsoon relation during the 20th Century

    Science.gov (United States)

    Vega Martín, Inmaculada; Gallego Puyol, David; Ribera Rodriguez, Pedro; Gómez Delgado, Francisco de Paula; Peña-Ortiz, Cristina

    2017-04-01

    The concept of the Western North Pacific Summer Monsoon (WNPSM) appeared for the first time in 1987. Unlike the Indian Summer Monsoon and the East Asian summer monsoon, the WNPSM is an oceanic monsoon driven essentially by the meridional gradient of sea surface temperature. Its circulation is characterized by a northwest-southeast oriented monsoon trough with intense precipitation and low-level southwesterlies and upper-tropospheric easterlies in the region [100°-130° E, 5°-15°N]. Although this monsoon is mainly oceanic, it modulates the precipitation of densely populated areas such as the Philippines. To date, the WNPSM has been quantified by the so-called Western North Pacific Monsoon Index (WNPMI), an index based on wind anomalies over large domains of the Western Pacific. The requirement of continuous observed wind over remote oceanic areas to compute the WNPMI has limited its availability to the 1949-2014 period. In this work we have extended the index by almost 100 years by using historical observations of wind direction taken aboard ships. Our Western North Pacific Directional Index (WNPDI), is defined as the sum of the persistence of the low-level westerly winds in [5°-15°N, 100°-130°E] and easterly winds in [20°-30°N, 110°-140°E]. The new WNPDI index is highly correlated to the existent WNPMI for the concurrent period (1948-2014). (r=+0.88, pCompetitividad through the project INCITE (CGL2013-44530-P, BES-2014-069733).

  11. North Pacific Decadal Variability in the GEOS-5 Atmosphere-Ocean Model

    Science.gov (United States)

    Achuthavarier, Deepthi; Schubert, Siegfried D.; Vikhliaev, Yury V.

    2013-01-01

    This study examines the mechanisms of the Pacific decadal oscillation (PDO) in the GEOS-5 general circulation model. The model simulates a realistic PDO pattern that is resolved as the first empirical orthogonal function (EOF) of winter sea surface temperature (SST). The simulated PDO is primarily forced by Aleutian low through Ekman transport and surface fluxes, and shows a red spectrum without any preferred periodicity. This differs from the observations, which indicate a greater role of El Nino-Southern Oscillation (ENSO) forcing, and likely reflects the too short time scale of the simulated ENSO. The geostrophic transport in response to the Aleutian low is limited to the Kuroshio-Oyashio Extension, and is unlikely the main controlling factor in this model, although it reinforces the Ekman-induced SST anomalies. The delay between the Aleutian low and the PDO is relatively short (1 year) suggesting that the fast Ekman response (rather than Rossby wave propagation) sets the SST pattern immediately following an Aleutian low fluctuation. The atmospheric feedback (response to the SST) is only about 25 of the forcing and never evolves into an Aleutian low completely, instead projecting onto the North Pacific Oscillation (NPO), a meridional dipole in sea level pressure (SLP). The lack of preferred periodicity and weak atmospheric response bothindicate a coupled oscillation is an unlikely mechanism for the PDO in this model. In agreement with recent studies, the NPO is correlated with the North Pacific Gyre Oscillation (NPGO), which is another leading EOF of the North Pacific SST. A possible connection between the PDO and the NPGO is discussed.

  12. An Analysis of North Pacific Subsurface Temperatures Using State-Space Techniques

    CERN Document Server

    Bessey, Cindy

    2012-01-01

    North Pacific subsurface temperature data from the Simple Ocean Data Assimilation model at 10m, 50m, 75m, 100m and 150m depths, are analyzed using a combination of state-space decomposition and subspace identification techniques to examine the spatial structure of thermal variability within the upper water column. We identify four common trends from our analysis that display the major broad-scale patterns in the North Pacific over a 47 year period (1958-2004): (1) a basin-wide near-surface warming trend that identifies the mid 1980's as a change point from a cooling to a warming trend; (2) a contrasting cooling in the central basin and warming along the coast of North America that began in the early 1970's; (3) a cooling along the transition zone and the west coast of North America that becomes dominant around 1998; (4) and contrasting differences in the subarctic and subtropical gyres displaying differences in processes at each depth. We also provide a detailed analysis of the temperature variability at four...

  13. Anthropogenic {sup 129}I in the North Pacific, Bering and Chukchi Seas, and Arctic Ocean in 2012–2013

    Energy Technology Data Exchange (ETDEWEB)

    Nagai, H., E-mail: hnagai@chs.nihon-u.ac.jp [Department of Chemistry, College of Humanities and Sciences, Nihon University, Tokyo 156-8550 (Japan); Hasegawa, A. [Graduate School of Integrated Basic Sciences, Nihon University, Tokyo 156-8550 (Japan); Yamagata, T. [Department of Chemistry, College of Humanities and Sciences, Nihon University, Tokyo 156-8550 (Japan); Kumamoto, Y.; Nishino, S. [Japan Agency for Marine-Earth Science and Technology, Kanagawa 237-0061 (Japan); Matsuzaki, H. [Department of Nuclear Engineering and Management, The University of Tokyo, Tokyo 113-0032 (Japan)

    2015-10-15

    Most of anthropogenic {sup 129}I in marine environment are due to discharge from the nuclear fuel reprocessing facilities at Sellafield (U.K.) and La Hague (France) for past few decades. The discharge raised {sup 129}I concentration in seawaters in the North Atlantic and Arctic Oceans to more than 10{sup 9} atoms L{sup −1}, which is two orders of magnitude higher than that in other region. Recently, in March 2011, a large quantity of {sup 129}I was released into the western North Pacific due to the Fukushima Daiichi Nuclear Power Plant (F1NPP) accident. To evaluate the influence of these events, we have measured {sup 129}I concentration in seawaters in the northern North Pacific Ocean, Bering and Chukchi Seas, and Arctic Ocean in 2012–2013. The {sup 129}I concentrations were 1.0–1.8 × 10{sup 7} atoms L{sup −1} in the surface waters in the vicinity of 47°N 150°E–130°W North Pacific Ocean, Bering Sea, and Chukchi Sea (<74°N), which are equal to or lower than the {sup 129}I concentration level in surface water in the North Pacific Ocean before the F1NPP accident. The vertical profiles in the North Pacific were almost same as that observed in the western North Pacific before the F1NPP accident. The {sup 129}I distribution in seawater in the North Pacific to the Chukchi Sea revealed no significant increase of {sup 129}I concentration caused by the F1NPP accident. The {sup 129}I concentrations were 13–14 × 10{sup 7} atoms L{sup −1} in surface waters and 80 × 10{sup 7} atoms L{sup −1} at depths of 300 and 800 m in the Arctic Ocean.

  14. Seasonal variation of the surface North Equatorial Countercurrent (NECC) in the western Pacific Ocean

    Science.gov (United States)

    Zhao, Jun; Li, Yuanlong; Wang, Fan

    2016-11-01

    The North Equatorial Countercurrent (NECC) is an important zonal flow in the upper circulation of the tropical Pacific Ocean, which plays a vital role in the heat budget of the western Pacific warm pool. Using satellite-derived data of ocean surface currents and sea surface heights (SSHs) from 1992 to 2011, the seasonal variation of the surface NECC in the western tropical Pacific Ocean was investigated. It was found that the intensity (INT) and axis position (Y CM ) of the surface NECC exhibit strikingly different seasonal fluctuations in the upstream (128°-136°E) and downstream (145°-160°E) regions. Of the two regions, the seasonal cycle of the upstream NECC shows the greater interannual variability. Its INT and YCM are greatly influenced by variations of the Mindanao Eddy, Mindanao Dome (MD), and equatorial Rossby waves to its south. Both INT and Y CM also show semiannual signals induced by the combined effects of equatorial Rossby waves from the Central Pacific and local wind forcing in the western Pacific Ocean. In the downstream region, the variability of the NECC is affected by SSH anomalies in the MD and the central equatorial Pacific Ocean. Those in the MD region are especially important in modulating the YCM of the downstream NECC. In addition to the SSH-related geostrophic flow, zonal Ekman flow driven by meridional wind stress also plays a role, having considerable impact on INT variability of the surface NECC. The contrasting features of the variability of the NECC in the upstream and downstream regions reflect the high complexity of regional ocean dynamics.

  15. Investigating the 'Iron Hypothesis' in the North Pacific: Trans-Pacific Dust and Methanesulfonate (MSA) in the Denali Ice Core, Alaska

    Science.gov (United States)

    Saylor, P. L.; Osterberg, E. C.; Winski, D.; Ferris, D. G.; Koffman, B. G.; Kreutz, K. J.; Wake, C. P.; Campbell, S. W.

    2015-12-01

    Oceanic deposition of Asian-sourced, Iron-rich dust particulate has been linked to enhanced phytoplankton productivity in regions of the Pacific Ocean. High Nutrient Low Chlorophyll (HNLC) ocean regions, such as the North Pacific, are hypothesized to play a significant role in changing atmospheric CO­2 concentrations on glacial-interglacial timescales. Phytoplankton blooms generate methanesulfonate (MSA), an atmospheric oxidation product of dimethylsulfide (DMS) that is readily aerosolized and deposited in nearby glacial ice. In the summer of 2013, an NSF-funded team from Dartmouth College and the Universities of Maine and New Hampshire collected two 1000 year-long parallel ice cores to bedrock from the summit plateau of Mount Hunter in Denali National Park, Alaska (62.940° N, 151.088° W, 3912 m elevation). The Mt. Hunter ice core site is well situated to record changes in trans-Pacific dust flux and MSA emissions in the North Pacific. Here we investigate the history of dust flux to Denali over the last millennium using major and trace element chemistry and microparticle concentration and size distribution data from the Mt. Hunter cores. We evaluate potential controlling mechanisms on Denali dust flux including conditions at Asian dust sources (storminess, wind speed, precipitation), the strength of the Aleutian Low, and large-scale climate modes such as the El Niño-Southern Oscillation and the Pacific Decadal Oscillation. We also evaluate the Mt. Hunter record for relationships between dust flux and MSA concentrations to investigate whether dust fertilization enhanced North Pacific phytoplankton production over the past 1000 years. Future work will create a composite North Pacific dust record using new and existing Mt. Logan ice core records to evaluate these relationships over the entire Holocene.

  16. Phylogenetics and biogeography of eastern Asian-North American disjunct genus Pachysandra (Buxaceae) inferred from nucleotide sequences

    Institute of Scientific and Technical Information of China (English)

    Zhi-hua JIAO; Jian-hua LI

    2009-01-01

    Pachysandra is an eastern Asian-North American disjunct genus with three species, two in eastern Asia (Pachysandra axillaris and Pachysandra terminalis) and one in eastern North America (Pachysandra procumbens). Although morphological and cytological studies suggest a close affinity of Pprocumbens with P axillaris, molecular data from nuclear and chloroplast DNA regions have provided conflicting signals. In this study, we tested previous phylogenetic hypotheses using sequences of nuclear ribosomal DNA internal transcribed spacers and chloroplast ndhF gene from multiple individuals of each of the three species. We also estimated the time of divergence between eastern Asia and eastern North America. Our results support the morphological and cytological conclusion that P procumbens is more closely related to P axillaris than to P terminalis. The estimated time of divergence of P axillaris and P procumbens was 14.64-5.5 mya, consistent with estimates from many other eastern Asian-North American disjunct genera. The migration of Pachysandra populations from eastern Asia to North America might have occurred by way of the North Atlantic land bridge.

  17. Transition Fault and the Yakutat-Pacific-North American Triple Junction

    Science.gov (United States)

    Gulick, S. P.; Christeson, G. L.; Norton, I. O.; Pavlis, T. L.; Reece, R.; van Avendonk, H.; Worthington, L. L.

    2011-12-01

    In the Gulf of Alaska the Pacific Plate, Yakutat Terrane, and North American Plate interact in a complexly deformed zone on the continental slope near Kayak Island. This zone can be viewed as a fault-trench-trench (FTT) triple junction that can only be stable if the two trench segments are aligned. In this case the trench segments are: the deformation front along which the Pacific Plate subducts beneath North America (the Aleutian Trench) and the deformation front along which the Yakutat Terrane subducts at a more westerly direction (when compared to the Pacific subduction) beneath North America (the Pamplona Zone). These two deformation fronts are, to a first order, locally aligned. The complex member of the system is the Transition Fault which is a long-lived strike-slip fault separating the 15-30 km thick Yakutat oceanic plateau crust from the 5-7 km thick Pacific Plate crust, which is itself deforming along the north-south trending Gulf of Alaska Shear Zone (GASZ). A series of seismic reflection profiles crossing the Transition Fault allow us to examine the evolution of deformation as a function of proximity to the triple junction. East of the triple junction and the GASZ, the Transition Fault is a single near vertical strike-slip zone. Moving west to the area where the GASZ interacts with the Transition Fault, three seismic profiles show that the Fault bifurcates into a southern transpressional strand with a few 100 meters of seafloor relief and a northern strike-slip dominated strand. West of the GASZ and within the region proximal to the triple junction, two seismic lines show that the Transition Fault is expressed as a southern transpressional structure with significant amounts shortening (seafloor expression increased to ~1.8 km) and a northern dominantly strike-slip fault with minor transpression. Mapping the top of basement shows that the southern arm lies within and deforms the Pacific oceanic crust with the top of ocean crust reflection to the north

  18. Evidence for a Southern Pattern of Deglacial Surface Warming in the Eastern Equatorial Pacific

    Science.gov (United States)

    Spero, H. J.; Schmidt, M. W.; Lea, D. W.; Lavagnino, L.

    2009-12-01

    The timing of both Southern and Northern hemisphere warming patterns has been used to explain tropical Pacific warming at the end of the last glacial period. Despite the importance of resolving this deglacial tropical-polar connection, the controversy is still ongoing (Koutavas & Sachs, 2008; Lea et al., 2000, 2006). For instance, the initiation of eastern equatorial Pacific (EEP) surface warming, derived from Mg/Ca analyses of the surface-dwelling foraminifera Globigerinoides ruber, shows a clear correlation with the Southern hemisphere. In contrast, alkenone-derived temperatures from the EEP indicate tropical warming occurred at least 3 kyr later than that implied from Mg/Ca data, thereby suggesting a Northern hemisphere link to initial SST rise. Here, we use a multispecies, multiproxy approach that is based on fundamental foraminifera biology to resolve this controversy. Laboratory experiments demonstrate the final shell size of symbiont-bearing foraminifera varies primarily as a function of the light level (=symbiont photosynthetic rate) that an individual grew under. Because light decreases exponentially in the water column, and the EEP is highly stratified with a shallow mixed layer and cold thermocline, we hypothesize that symbiotic foraminifera with a broad habitat range such as Globigerinoides sacculifer, should produce smaller shells in the more dimly lit cold thermocline than individuals growing in the more illuminated mixed layer. Moreover, these larger shells should contain a temperature signal that is similar to G. ruber, which is constrained to the shallow mixed layer. Mg/Ca and δ18O analyses conducted on 350-400 μm and >650 μm sized G. sacculifer from EEP core TR163-19 (2N, 91W, 2348) demonstrate large specimens yield Mg/Ca and δ18O that are similar to data published previously for mixed layer dwelling G. ruber. In contrast, small G. sacculifer record significantly higher δ18O and lower Mg/Ca temperatures that are consistent with a shallow

  19. Simulation of the intraseasonal variability over the Eastern Pacific ITCZ in climate models

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Xianan [Univ. of California, Los Angeles, CA (United States); Waliser, Duane E. [California Inst. of Technology (CalTech), La Canada Flintridge, CA (United States). Jet Propulsion Lab.; Kim, Daehyun [Columbia Univ., New York, NY (United States); Zhao, Ming [Princeton Univ., NJ (United States); Sperber, Kenneth R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Stern, William F. [Princeton Univ., NJ (United States); Schubert, Siegfried D. [NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States); Zhang, Guang J. [Scripps Institute of Oceanography. La Jolla, California (United States); Wang, Wanqiu [National Oceanic and Atmospheric Administration (NOAA), National Centers for Environmental Protection. Camp Springs, MD (United States); Khairoutdinov, Marat [Institute for Terrestrial and Planetary Atmospheres. Stony Brook Univ., NY (United States); Neale, Richard B. [National Center for Atmospheric Research. Boulder, CO (United States); Lee, Myong-In [Ulsan National Institute for Science and Technology. Seoul (Korea)

    2012-08-01

    During boreal summer, convective activity over the eastern Pacific (EPAC) inter-tropical convergence zone (ITCZ) exhibits vigorous intraseasonal variability (ISV). Previous observational studies identified two dominant ISV modes over the EPAC, i.e., a 40-day mode and a quasi-biweekly mode (QBM). The 40-day ISV mode is generally considered a local expression of the Madden-Julian Oscillation. However, in addition to the eastward propagation, northward propagation of the 40-day mode is also evident. The QBM mode bears a smaller spatial scale than the 40-day mode, and is largely characterized by northward propagation. While the ISV over the EPAC exerts significant influences on regional climate/weather systems, investigation of contemporary model capabilities in representing these ISV modes over the EPAC is limited. In this study, the model fidelity in representing these two dominant ISV modes over the EPAC is assessed by analyzing six atmospheric and three coupled general circulation models (GCMs), including one super-parameterized GCM (SPCAM) and one recently developed high-resolution GCM (GFDL HIRAM) with horizontal resolution of about 50 km. While it remains challenging for GCMs to faithfully represent these two ISV modes including their amplitude, evolution patterns, and periodicities, encouraging simulations are also noted. In general, SPCAM and HIRAM exhibit relatively superior skill in representing the two ISV modes over the EPAC. While the advantage of SPCAM is achieved through explicit representation of the cumulus process by the embedded 2-D cloud resolving models, the improved representation in HIRAM could be ascribed to the employment of a strongly entraining plume cumulus scheme, which inhibits the deep convection, and thus effectively enhances the stratiform rainfall. The sensitivity tests based on HIRAM also suggest that fine horizontal resolution could also be conducive to realistically capture the ISV over the EPAC, particularly for the QBM mode

  20. Exploring Paleoclimatic and -Oceanographic Consequences for Arctic Beringia by the Eocene Formation and Progressive E-W Lengthening of the Aleutian Ridge (arc) Across the North Pacific Basin

    Science.gov (United States)

    Scholl, D. W.

    2013-12-01

    INTRODUCTION: During the past ~50 Myr, magmatic growth of the offshore Aleutian Ridge (AR) or arc and its progressive tectonic lengthening to the west cordoned off the NW corner of the Pacific Basin to formed the deep water (3000-4000 m), marginal sea of the Bering Sea Basin (BSB). Cordoning continuously altered the paths, depths, and locations of water-exchange passes controlling the circulation of waters between the north Pacific and the Bering Sea (BS), and, via the fixed Bering Strait, that entering the Pacific sector of the Arctic Basin. PRESENT PATTERN OF PACIFIC-BERING-ARCTIC WATER EXCHANGE: Cool, low salinity water of the Alaska Stream flowing west along the Pacific side of the AR crosses northward into the BS via tectonically controlled, inter-island passes. The largest volume (~9 SV) enters near the western end of the AR via Near Pass. Flow turns back to the east and CCW northward over the BSB. Surface water exits southward around the western end of the AR through the far western, deep-water (~4000 m) pass of Kamchatka Strait. Because water salinity is low, vertical thermohaline circulation (THC) does not occur over the BSB. However, the deposition of the larger Meiji Drift body, which is charged with Bering-sourced, detritus, on the Pacific side of Kamchatka Strait implies THC may have occurred in the past. Deep-water circulation is presently linked to the inflow of Pacific abyssal water via Kamchatka Strait. A small volume (~0.8 SV) of cool, low salinity water entering the BS mainly through eastern, shallow-silled passes continues northward across the broad Beringian shelf to enter the Arctic Ocean via the Bering Strait. EVOLUTION OF ALEUTIAN RIDGE: At it's inception, the arc massif of the AR likely extended only about 1200 km west of Alaska. Because convergence is increasingly oblique to the west, plate-boundary-driven, right-lateral strike-slip faulting extensionally fragmented the AR and progressively rotated and transported blocks and slivers

  1. Cenozoic structures and the tectonic evolution of the eastern North Sea

    DEFF Research Database (Denmark)

    Clausen, O.R.; Nielsen, S.B.; Egholm, D.L.

    2011-01-01

    Abundant seismic sections and well data from the Cenozoic succession in the eastern North Sea area generally reveal normal faulting, salt tectonics and localized tectonic inversion. However, inferences on the Cenozoic dynamic evolution of the region require thorough analysis of interactions between....... These structures have in the last decades been an integrated part of the discussions about subsidence and uplift of not only the interior of the basin but also of the basin margin. Abundant 2D and 3D seismic data and new depositional models enable detailed analysis and reinterpretation of where and when basement...... or cover tectonism took place. Our objectives are thus 1) to analyze the interaction between basement and cover structures, and if possible 2) to relate the structures to the regional tectonic evolution. The Zechstein evaporites pinch out onto the Ringkøbing-Fyn High, which in the eastern North Sea...

  2. Cenozoic structures and the tectonic evolution of the eastern North Sea

    DEFF Research Database (Denmark)

    Clausen, O.R.; Nielsen, S.B.; Egholm, D.L.

    2011-01-01

    Abundant seismic sections and well data from the Cenozoic succession in the eastern North Sea area generally reveal normal faulting, salt tectonics and localized tectonic inversion. However, inferences on the Cenozoic dynamic evolution of the region require thorough analysis of interactions between...... or cover tectonism took place. Our objectives are thus 1) to analyze the interaction between basement and cover structures, and if possible 2) to relate the structures to the regional tectonic evolution. The Zechstein evaporites pinch out onto the Ringkøbing-Fyn High, which in the eastern North Sea...... influencede.g. Miocene deposition and controlled the generation of second order faults. The latter detached along the top Chalk Group due to the topography generated during faulting, i.e. they are second order detachment surfaces. We conclude that the regional tectonic significance of the Cenozoic structures...

  3. Late Ordovician-Early Silurian chitinozoans from north-eastern and western Illinois, USA

    Science.gov (United States)

    Butcher, A.; Mikulic, Donald G.; Kluessendorf, Joanne

    2010-01-01

    Samples of uppermost Ordovician and Silurian strata from two cores from north-eastern and western Illinois were processed for chitinozoans. Due to apparent sea-floor oxidation or palaeoenvironmental constraints, very few samples yielded specimens, but those that did allow tentative correlation with established biostratigraphical zonations for the Chitinozoa. Samples from the Wilhelmi Formation of core DH76-21 in north-eastern Illinois yielded Spinachitina fragilis, a typically earliest Silurian taxon. A sample from the Maquoketa Group strata of core Principia #4, western Illinois, yielded a monospecific assemblage of Conochitina elegans, which is suggestive of a late Ordovician age. Higher in this core, a sample from the upper strata of the Bowling Green Dolomite yielded an assemblage indicating a late Rhuddanian to Aeronian age, including Angochitina hansonica, previously only described from strata in Nevada, and one new species, Fungochitina illinoisensis. ?? 2009 Elsevier B.V. All rights reserved.

  4. Role of Western Hemisphere Warm Pool in Rapid Climate Changes over the Western North Pacific

    Science.gov (United States)

    Kug, Jong-Seong; Park, Jae-Heung; An, Soon-Il

    2017-04-01

    Oceanic states over the western North Pacific (WNP), which is surrounded by heavily populated countries, are closely tied to the lives of the people in East Asia in regards to both climate and socioeconomics. As global warming continues, remarkable increases in sea surface temperature (SST) and sea surface height (SSH) have been observed in the WNP in recent decades. Here, we show that the SST increase in the western hemisphere warm pool (WHWP), which is the second largest warm pool on the globe, has contributed considerably to the rapid surface warming and sea level rise in the WNP via its remote teleconnection along the Pacific Intertropical Convergence Zone (ITCZ). State-of-the-art climate models strongly support the role of the WHWP not only on interannual time sales but also in long-term climate projections. We expect that understanding the processes initiated by the WHWP-SST could permit better forecasts of western North Pacific climate and the further development of the socioeconomics of East Asia.

  5. An Observing System Simulation Experiment for the Western North Pacific Region

    Directory of Open Access Journals (Sweden)

    Shuhei Masuda

    2014-01-01

    Full Text Available This study investigated the effectiveness of concentrated observations for ocean state estimation in a region remote from the observation site. I executed a twin observing system simulation experiment (OSSE for the North Pacific region, using an ocean data synthesis system, to examine how the potential effectiveness is for a well-defined criterion, the representativeness of the subsurface salinity minimum corresponding to North Pacific Intermediate Water (NPIW. The results of the OSSE show that data synthesis confined to the region corresponding to the recent origin of the NPIW (35°N–53°N, 130°E–170°E can affect the modeled extent of the NPIW in the central Pacific at 35°N, 180°. The interannual variability of the NPIW is not well reproduced in terms of the standard deviation value (std, only by the data input in the origin region. The root mean square difference between the “true” and the synthesized field is twice larger than the std although there the representativeness of the scale of salinity minimum is improved by about one-third of the difference between the “true” and “first-guess” fields in a snapshot. These results imply that combinations of concentrated and other in situ observations should be required for the dynamic state estimation of the NPIW.

  6. Responses of the East Asian jet stream to the North Pacific subtropical front in spring

    Science.gov (United States)

    Zhang, Leying; Xu, Haiming; Shi, Ning; Deng, Jiechun

    2017-02-01

    This study concerns atmospheric responses to the North Pacific subtropical front (NPSTF) in boreal spring over the period 1982-2014. Statistical results show that a strong NPSTF in spring can significantly enhance the East Asian jet stream (EAJS). Both transient eddy activity and the atmospheric heat source play important roles in this process. The enhanced atmospheric temperature gradient due to a strong NPSTF increases atmospheric baroclinicity, resulting in an intensification of transient eddy and convection activities. On the one hand, the enhanced transient eddy activities can excite an anomalous cyclonic circulation with a quasi-baraotropical structure in the troposphere to the north of the NPSTF. Accordingly, the related westerly wind anomalies around 30°N can intensify the component of the EAJS over the Northeast Pacific. On the other hand, an enhanced atmospheric heat source over the NPSTF, which is related to increased rainfall, acts to excite an anomalous cyclonic circulation system in the troposphere to the northwest of the NPSTF, which can explain the enhanced component of the EAJS over the Northwest Pacific. The two mechanisms may combine to enhance the EAJS.

  7. North Pacific Modulation of the Global Carbon Cycle Through MIS-2: Insights from IODP Expedition 341

    Science.gov (United States)

    Walczak, M. H.; Mix, A.; Fallon, S.; Fifield, L. K.; Hobern, T.

    2016-12-01

    IODP Expedition 341 Site U1419, at 680 m water depth on the upper continental slope of the Gulf of Alaska, experienced 90 m of sediment accumulation over the past 50,000 years. Paired benthic-planktic radiocarbon dates from U1419, as well as site survey piston core EW0408-85JC, potentially record millennial-scale variability in North Pacific Ocean ventilation from recent stadial MIS-2 through the Holocene. The modern site is bathed in North Pacific Intermediate Water (NPIW), with a modern (pre-bomb) surface ocean reservoir age of 880 ± 80 years and bottom waters aged an additional 510 ± 130 years. Over the past 11,000 years B-P differences vary smoothly, averaging 745 ± 120 years (n = 21). Throughout the MIS-2 portion of the record average B-P differences are a similar 765 ± 260 (n=63), but display significantly different structure with three abrupt increases to >1000 years centered at 25,500, 17,500 and 12,500 cal ybp. All three of these events correspond with periods of increasing atmospheric CO2, with the latter two and largest (B-P differences approaching 1,500 years) events corresponding to the episodes of rapid atmospheric CO2 rise during Termination 1. This may reflect the transient presence of an older intermediate water mass extending to the high-latitude Northeast Pacific associated with reorganization of circulation in the Southern Ocean.

  8. Historic and Contemporary Status of Sea Otters in the North Pacific

    Science.gov (United States)

    Bodkin, James L.; Larson, Shawn E.; Bodkin, James L; Vanblaricom, Glenn R.

    2015-01-01

    Similar to other species that in recent centuries experienced unregulated human exploitation, sea otters were extirpated throughout large portions of their historic range in the North Pacific. For most of the twentieth century, with cessation of the fur trade and because of concerted efforts at conservation, sea otters recovered much of their historic range and abundance. Late in the twentieth century, increased predation by killer whales in southwest Alaska drove sea otter populations to a few percentage points of their prior abundance, and one of the nation’s largest oil spills in south-central Alaska caused the death of several thousand animals and required more than two decades for recovery. In California, entanglement in fishing gear and environmental degradation, among other factors, have contributed to slow growth in sea otter abundance. We discuss the role of density dependence and spatial structuring of populations in reduced rates of sea otter recovery recently detected in the Northeast Pacific, and consider the potential effects of multiple low-level and cumulative threats on sea otter populations. The resilience demonstrated by sea otters over the past century will be tested in upcoming decades as human activities continue to degrade nearshore coastal areas of the North Pacific.

  9. Effects of the Yakutat terrane collision with North America on the neighboring Pacific plate

    Science.gov (United States)

    Reece, R.; Gulick, S. P.; Christeson, G. L.; Barth, G. A.; van Avendonk, H.

    2011-12-01

    High-resolution bathymetry data show a 30 km N-S trending ridge within the deep-sea Surveyor Fan between the mouths of the Yakutat Sea Valley and Bering Trough in the Gulf of Alaska. The ridge originates in the north, perpendicular to and at the base of the continental slope, coincident with the Transition Fault, the strike-slip boundary between the Yakutat terrane (YAK) and the Pacific plate (PAC). The ridge exhibits greatest relief adjacent to the Transition Fault, and becomes less distinct farther from the shelf edge. Seismic reflection data reveal a sharp basement high beneath the ridge (1.1 sec of relief above "normal" basement in two-way travel time) as well as multiple similarly oriented strike-slip fault segments. The ridge, basement high, and faults are aligned and co-located with an intraplate earthquake swarm on the PAC, which includes four events > 6.5 Mw that occurred from 1987-1992. The swarm is defined by right-lateral strike-slip events, and is collectively called the Gulf of Alaska Shear Zone (GASZ). Based on the extent of historic seismicity, the GASZ extends at least 230 km into the PAC, seemingly ending at the Kodiak-Bowie Seamount Chain. Farther southwest, between the Kodiak-Bowie and Patton-Murray Seamount Chains, there is a large regional bathymetric low with an axis centered along the Aja Fracture Zone, perpendicular to the GASZ and Aleutian Trench. Basement and overlying sediment in the low are irregularly, but pervasively faulted. The GASZ and faulted bathymetric low could represent PAC deformation due to PAC-YAK coupling whereby YAK resistance to subduction is expressed as deformation in the thinner (weaker) PAC crust. The YAK is an allochthonous, basaltic terrane coupled to the PAC that began subducting at a low angle beneath North America (NA) ~25-40 Ma. Due to its 15-25 km thickness, the YAK is resistant to subduction compared to the normal oceanic crust of the PAC. As a result the plates developed differential motion along the

  10. Aerobic Anoxygenic Phototrophic Bacteria in the Mid-Atlantic Bight and the North Pacific Gyre. Revised

    Science.gov (United States)

    Cottrell, Matthew T.; Mannino, Antonio; Kirchman, David L.

    2005-01-01

    The abundance of aerobic anoxygenic phototrophic (AM) bacteria, cyanobacteria and heterotrophs was examined in the Mid-Atlantic Bight and the central North Pacific gyre using infrared fluorescence microscopy coupled with image analysis and flow cytometry. AAP bacteria comprised 5% to 16% of total prokaryotes in the Atlantic but only 5% or less in the Pacific. In the Atlantic, AAP bacterial abundance was as much as 2-fold higher than Prochlorococcus and 10-folder higher than Synechococcus. In contrast, Prochlorococcus outnumbered AAP bacteria 5- to 50-fold in the Pacific. In both oceans, subsurface abundance maxima occurred within the photic zone, and AAP bacteria were least abundant below the 1% light depth. Concentrations of bacteriochlorophyll a (BChl a) were low (approx.1%) compared to chlorophyll a. Although the BChl a content of AAP bacteria per cell was typically 20- to 250-fold lower than the divinyl-chlorophyll a content of Prochlorococcus, in shelf break water the pigment content of AAP bacteria approached that of Prochlorococcus. The abundance of AAP bacteria rivaled some groups of strictly heterotrophic bacteria and was often higher than the abundance of known AAP genera (Erythrobacter and Roseobacter spp.). The distribution of AAP bacteria in the water column, which was similar in the Atlantic and the Pacific, was consistent with phototrophy.

  11. Quality Control and First Insights on the Variability of Surface Wind Observations for North Eastern North America

    Science.gov (United States)

    Lucio-Eceiza, E.; González-Rouco, F. J.; Navarro Montesinos, J.; Hidalgo; Jiménez, P.; García-Bustamante, E.; Conte, J.; Casabella, N.; Beltrami, H.

    2013-12-01

    Over the last decades, a policy change in energy sources has been fostered in Atlantic Canada. The purpose of this has been to reduce the dependency on energy produced abroad and to propose feasible alternatives with the aim of reducing greenhouse emissions. The region offers a high potential for the development of wind energy facilities and studies within the framework of wind resource assessment are encouraged. Studies of this nature rely on the quality of observational data. Henceforth, it is essential to develop procedures that ensure the reliability of observations before they are subjected to any subsequent analysis. This work summarizes the Quality Control process applied to an observational database of surface wind module and direction in North Eastern North America. The data set consists of 525 stations compiled from three different sources: 344 land sites from Environment Canada (EC; 1940-2009) located in the provinces of Atlantic Canada and Quebec; 40 buoys distributed over the East Coast and the Canadian Great Lakes provided by Fisheries and Oceans Canada (FOC; 1988-2008); and 141 land sites over both Eastern Canada and North Eastern USA provided by the National Center of Atmospheric Research (NCAR; 1975-2010). The process comprises different phases that: 1) unify measurement units and recording times; 2) find accidentally duplicated periods of data within a time series or between different stations; 3) check for physical consistency in the ranges of values; 4) detect time intervals of anomalous low and high variability; and 5) look for long term biases in mean and variance. The temporal extension and resolution of the quality controlled database allows to explore the wind variability at different temporal scales, from daily to multidecadal. This contribution will present a first assessment of the wind field climatology in the region, including a description of long term trends, analogous of wind circulation regimes and their relationship to large scale

  12. Cultural Resources, Studies, Eastern North Carolina Above Cape Lookout, Literature Review and Preliminary Research Design.

    Science.gov (United States)

    1986-05-01

    inhabitants and activities of New Bern in the years im- mediately following the War of 1812. Most enlightening ; usually reliable. Mobley 1981 is an...Virginia upon the development of the [- Albemarle would be highly enlightening . 2-67 1 CHAPTER 3 ARCHITECTURAL RESOURCES OF THE EASTERN NORTH CAROLINA...trends. Georgian, Federal, Greek Revival, Gothic Revival, and Italianate styles, though sometimes retarditaire in nature, predominated. Builders and

  13. Seasonal Variation in the Measurement of Urinary Pesticide Metabolites among Latino Farmworkers in Eastern North Carolina

    OpenAIRE

    2009-01-01

    This analysis describes the detection of urinary pesticide metabolites for Latino farmworkers across the agricultural season. Two hundred and eighty four farmworkers were recruited from 44 camps in eastern North Carolina in 2007. Data were collected at one month intervals for a total of 939 data points. The OP insecticide metabolites 3,5,6-trichloropyridinol (46.2%), malathion dicarboxylic acid (27.7%), and para-nitrophenol (97.4%); the pyrethroid metabolite 3-phenoxybenzoic acid (56.4%); and...

  14. Linx individual B132 from north-eastern Switzerland sighted in Trentino (northern Italy

    Directory of Open Access Journals (Sweden)

    Brugnoli A

    2008-10-01

    Full Text Available A subadult lynx was caught in February 2008 in the Swiss National Park, fitted with a Gps-Gsm radio-collar and later genetically identified as B132 - i.e., a male born in 2006 in North-Eastern Switzerland -. B132 is at present located in the western Trentino region, more than 200 km away from his mother's home range. This is the furthest dispersal ever documented outside of Scandinavia for a Eurasian lynx.

  15. Marine biodiversity of an Eastern Tropical Pacific oceanic island, Isla del Coco, Costa Rica

    Directory of Open Access Journals (Sweden)

    Jorge Cortés

    2012-11-01

    Full Text Available Isla del Coco (also known as Cocos Island is an oceanic island in the Eastern Tropical Pacific; it is part of the largest national park of Costa Rica and a UNESCO World Heritage Site. The island has been visited since the 16th Century due to its abundance of freshwater and wood. Marine biodiversity studies of the island started in the late 19th Century, with an intense period of research in the 1930’s, and again from the mid 1990’s to the present. The information is scattered and, in some cases, in old publications that are difficult to access. Here I have compiled published records of the marine organisms of the island. At least 1688 species are recorded, with the gastropods (383 species, bony fishes (354 spp. and crustaceans (at least 263 spp. being the most species-rich groups; 45 species are endemic to Isla del Coco National Park (2.7% of the total. The number of species per kilometer of coastline and by square kilometer of seabed shallower than 200m deep are the highest recorded in the Eastern Tropical Pacific. Although the marine biodiversity of Isla del Coco is relatively well known, there are regions that need more exploration, for example, the south side, the pelagic environments, and deeper waters. Also, several groups of organisms, such as the flatworms, nematodes, nemerteans, and gelatinous zooplankton, have been observed around the Island but have been poorly studied or not at all.La Isla del Coco es una isla oceánica en el Pacífico Tropical Oriental; es parte del Parque Nacional más grande de Costa Rica y es un sitio de Patrimonio Mundial. La isla ha sido visitada desde el Siglo XVI por su abundancia de agua dulce y árboles. Estudios de biodiversidad marina de la isla empezaron a finales del Siglo XIX, con un intenso período de investigación en la década de 1930, y de nuevo desde mediados de la década de 1990 al presente. La información sobre organismos marinos se encuentra dispersa y en algunos casos en publicaciones

  16. Geocemical provinces of magmatism in the south-eastern part of the Pacific Ocean

    Science.gov (United States)

    Sushchevskaya, Nadezhda; Belyatsky, Boris; Teterin, Dmitry

    2010-05-01

    Comparison of geochemical signatures of island magmatism in the south-eastern part of the Pacific Ocean and tholeiites of the Bransfield and Powell rift zones revealed the similar character of the enrichment which reflects the melting of a close mantle source. But alkaline magmatism of the islands in the west of Antarctic and Marie Byrd Land differs from the enriched basalts of the northern province (Bransfield, Powell, BTJ) by showing more radiogenic Sr values and non-radiogenic Nd. The tectonic development of the South Ocean is characterized by its formation under stationary conditions of Antarctic continent. As a result of this, for the volcanic islands distributed at the western part of the Antarctic we observe no long mountain ridges typical for their development under conditions of the moving plate. Intraplate magmatism evolution was coincided with the extinction of the old subduction zones, formation of the new rift zones and separation of South America from Antarctic [Udintsev, Schenke, 2007; Teterin, 2008]. Such complicated geodynamics caused the possibility of formation of rupture cracks reaching the underlying metasomatizated mantle and decompression melting with further island formation. In Oligocene due to migration of asthenospheric flow from the west to east in the result of destruction of previously united continental blocks there was formed the Scotia Sea, South Sandwich island arc as well as Drake Passage. This caused the mechanical weakening of South Atlantic lithosphere and the starting at the end of Oligocene - beginning Miocene of the new plate border formation - American-Antarctic ridge, which propagated in the eastern direction till the Bouvet triple junction [Dubinin et al., 1999]. The close geochemical signatures of mantle source for islands basalts including the Bouvet Island and the enriched tholeiites of the western extremity of the SW Indian Ridge proves the development of a specific geochemical province enveloping the southeastern

  17. Integration of art and culture to develop the hotel business in North-eastern Thailand

    Directory of Open Access Journals (Sweden)

    Supaporn Sereerat

    2015-08-01

    Full Text Available This qualitative investigation had three research aims: 1 To study the history and background of the hotel industry in Isan; 2 To study the current situation and problems with using art in order to develop the tourism industry in Thailand; 3 To study the integration of art and culture to develop the hotel business in North-eastern Thailand. Nine hotels were selected from four provinces in North-eastern Thailand as the research population and the research sample was composed of 86 individuals. Tools used for data collection were survey, observation, interview, focus group discussion and workshop. Results show that hoteliers in North-eastern Thailand developed their businesses as a reaction to the economic crisis and failing trade. To attract more tourists to the region, hotel managers integrated traditional Thai art to their businesses, especially local Isan art. This investigation of nine hotels in Isan identified nine areas in which art has been integrated into hotel businesses. These are paintings, sculptures, architecture, literature, music and dance , the four Buddhist necessities of life (food, accommodation, clothing and medicine, beliefs, customs and ceremonies. By integrating elements of each of these categories into their hotels, business owners and managers have been able to generate extra trade

  18. Phylogeography of Labrus bergylta (Pisces: Labridae in the north-eastern Atlantic

    Directory of Open Access Journals (Sweden)

    Frederico Almada

    2015-12-01

    Full Text Available The ballan wrasse, Labrus bergylta (Labridae, is a protogynous hermaphrodite fish common in the north-eastern Atlantic from Norway to Morocco. It is a commercially important resource for local fisheries and is currently being used as cleaner fish to control sea lice in salmon farms in northern Europe. We analysed the phylogeographic patterns of this species using mitochondrial (control region and nuclear (I intron of the S7 gene markers in populations throughout its distributional range. The results revealed a marked genetic structure of L. bergylta along the sampled area, with a major separation found between the Archipelago of the Azores and all remaining locations and also a clear separation between the north-eastern Atlantic and Scandinavian locations. Similarly to other temperate species the genetic diversity decreased from north-eastern Atlantic to Scandinavian populations. Haplotype networks confirm the distinctiveness of the population from the Azores and show that Scandinavian populations also present some distinct haplotypes. The phylogeographic pattern and diversity indices found for the ballan wrasse are discussed and compared with others found for different labrid species. The recognition of different populations of L. bergylta may be an in important result for fisheries management and also for future regulation of capture and translocation of specimens to be used as cleaners in aquaculture facilities.

  19. Early diagenetic quartz formation at a deep iron oxidation front in the Eastern Equatorial Pacific

    Science.gov (United States)

    Meister, Patrick; Chapligin, Bernhard; Picard, Aude; Meyer, Hanno; Fischer, Cornelius; Rettenwander, Daniel; Amthauer, Georg; Vogt, Christoph; Aiello, Ivano

    2015-04-01

    The mechanisms of early diagenetic quartz formation under low-temperature conditions are still poorly understood. We studied lithified cherts consisting of microcrystalline quartz recovered from ODP Site 1226 in the Eastern Equatorial Pacific. The cherts occur near the base of a 420-m-thick Miocene-Holocene sequence within unlithified nannofossil and diatom ooze. Palaeo-temperatures reconstructed from δ18O values in the cherts are near to present porewater temperatures and a sharp depletion in dissolved silica occurs around 385 mbsf indicating that silica precipitation is still ongoing. Also a deep iron oxidation front occurs at the same depth, which is caused by upward diffusing nitrate from an oxic seawater aquifer in the underlying basaltic crust. Sequential iron extraction and analysis of the X-ray absorption near-edge structure (XANES) revealed that iron in the cherts predominantly occurs as illite and amorphous iron oxide, whereas iron in the nannofossil and diatom ooze occurs mainly as smectites. Mössbauer spectroscopy confirmed that the illite iron in the cherts is largely oxidized. A possible mechanisms that may be operative is quartz precipitation initiated by adsorption of silica to freshly precipitated iron oxides. The decrease in porewater silica concentration below opal-A and opal-CT saturation then allows for the precipitation of the thermodynamically more stable phase: quartz. We suggest that the formation of early-diagenetic chert at iron oxidation fronts is an important process in suboxic zones of silica-rich sediments. The largest iron oxidation front ever occurred during the great oxidation event ca. 2.5 Ga ago, when large amounts of iron and chert beds were deposited.

  20. Revisiting nitrification in the Eastern Tropical South Pacific: A focus on controls

    Science.gov (United States)

    Peng, Xuefeng; Fuchsman, Clara A.; Jayakumar, Amal; Warner, Mark J.; Devol, Allan H.; Ward, Bess B.

    2016-03-01

    Nitrification, the oxidation of ammonium (NH4+) to nitrite (NO2-) and to nitrate (NO3-), is a component of the nitrogen (N) cycle internal to the fixed N pool. In oxygen minimum zones (OMZs), which are hotspots for oceanic fixed N loss, nitrification plays a key role because it directly supplies substrates for denitrification and anaerobic ammonia oxidation (anammox), and may compete for substrates with these same processes. However, the control of oxygen and substrate concentrations on nitrification are not well understood. We performed onboard incubations with 15N-labeled substrates to measure rates of NH4+ and NO2- oxidation in the eastern tropical South Pacific (ETSP). The spatial and depth distributions of NH4+ and NO2- oxidation rates were primarily controlled by NH4+ and NO2- availability, oxygen concentration, and light. In the euphotic zone, nitrification was partially photoinhibited. In the anoxic layer, NH4+ oxidation was negligible or below detection, but high rates of NO2- oxidation were observed. NH4+ oxidation displayed extremely high affinity for both NH4+ and oxygen. The positive linear correlations between NH4+ oxidation rates and in situ NH4+ concentrations and ammonia monooxygenase subunit A (amoA) gene abundances in the upper oxycline indicate that the natural assemblage of ammonia oxidizers responds to in situNH4+ concentrations or supply by adjusting their population size, which determines the NH4+ oxidation potential. The depth distribution of archaeal and bacterial amoA gene abundances and N2O concentration, along with independently reported simultaneous direct N2O production rate measurements, suggests that AOA were predominantly responsible for NH4+ oxidation, which was a major source of N2O production at oxygen concentrations > 5 µM.

  1. Contribution of picoplankton to the total particulate organic carbon (POC concentration in the eastern South Pacific

    Directory of Open Access Journals (Sweden)

    C. Grob

    2007-05-01

    Full Text Available Prochlorococcus, Synechococcus, picophytoeukaryotes and bacterioplankton abundances and contributions to the total particulate organic carbon concentration (POC, derived from the total particle beam attenuation coefficient (cp, were determined across the eastern South Pacific between the Marquesas Islands and the coast of Chile. All flow cytometrically derived abundances decreased towards the hyper-oligotrophic centre of the gyre and were highest at the coast, except for Prochlorococcus, which is not detected under eutrophic conditions. Temperature and nutrient availability appeared important in modulating picophytoplankton abundance, according to the prevailing trophic conditions. Although the non-vegetal particles tended to dominate the cp signal everywhere along the transect (50 to 83%, this dominance seemed to weaken from oligo- to eutrophic conditions, the contributions by vegetal and non-vegetal particles being about equal under mature upwelling conditions. Spatial variability in the vegetal compartment was more important than the non-vegetal one in shaping the water column particulate attenuation coefficient. Spatial variability in picophytoplankton biomass could be traced by changes in both Tchla and cp. Finally, picophytoeukaryotes contributed with ~38% on average to the total integrated phytoplankton carbon biomass or vegetal attenuation signal along the transect, as determined by direct size measurements on cells sorted by flow cytometry and optical theory. The role of picophytoeukaryotes in carbon and energy flow would therefore be very important, even under hyper-oligotrophic conditions.

  2. Atmosphere-ocean linkages in the eastern equatorial Pacific over the early Pleistocene

    Science.gov (United States)

    Povea, Patricia; Cacho, Isabel; Moreno, Ana; Pena, Leopoldo D.; Menéndez, Melisa; Calvo, Eva; Canals, Miquel; Robinson, Rebecca S.; Méndez, Fernando J.; Flores, Jose-Abel

    2016-05-01

    Here we present a new set of high-resolution early Pleistocene records from the eastern equatorial Pacific (EEP). Sediment composition from Ocean Drilling Program Sites 1240 and 1238 is used to reconstruct past changes in the atmosphere-ocean system. Particularly remarkable is the presence of laminated diatom oozes (LDOs) during glacial periods between 1.85 and 2.25 Ma coinciding with high fluxes of opal and total organic carbon. Relatively low lithic particles (coarse and poorly sorted) and iron fluxes during these glacial periods indicate that the increased diatom productivity did not result from dust-stimulated fertilization events. We argue that glacial fertilization occurred through the advection of nutrient-rich waters from the Southern Ocean. In contrast, glacial periods after 1.85 Ma are characterized by enhanced dust transport of finer lithic particles acting as a new source of nutrients in the EEP. The benthic ecosystem shows dissimilar responses to the high productivity recorded during glacial periods before and after 1.85 Ma, which suggests that the transport processes delivering organic matter to the deep sea also changed. Different depositional processes are interpreted to be the result of two distinct glacial positions of the Intertropical Convergence Zone (ITCZ). Before 1.85 Ma, the ITCZ was above the equator, with weak local winds and enhanced wet deposition of dust. After 1.85 Ma, the glacial ITCZ was displaced northward, thus bringing stronger winds and stimulating upwelling in the EEP. The glacial period at 1.65 Ma with the most intense LDOs supports a rapid southward migration of the ITCZ comparable to those glacial periods before 1.85 Ma.

  3. Chemical composition of marine stratocumulus clouds over the eastern Pacific Ocean

    Science.gov (United States)

    Straub, Derek J.; Lee, Taehyoung; Collett, Jeffrey L.

    2007-02-01

    Samples of marine cloud water collected over the eastern Pacific Ocean have been analyzed for pH, major ions (Cl-, NO3-, SO42-, Na+, NH4+, K+, Ca2+, and Mg2+), hydrogen peroxide, formaldehyde, S(IV), Fe, Mn, and total organic carbon. The samples were obtained during the Dynamics and Chemistry of Marine Stratocumulus, Phase II (DYCOMS-II) field project in July 2001. These measurements represent a unique in situ description of cloud water composition for stratocumulus clouds residing in the remote marine boundary layer, a regime for which there are few published cloud water composition data. A wide range of concentrations was observed for each species of interest, including sodium (36-2784 μN), sulfate (15-905 μN), nitrate (3-205 μN), hydrogen peroxide (37.8-283.2 μM), formaldehyde (2.2-8.7 μM) and Fe (water concentrations with cloud liquid water content (LWC) and volume mean drop diameter show that dilution played a role in cloud drop solute concentration variations during individual flights and that solute concentrations are related to cloud drop size and ultimately to below-cloud aerosol number concentration. Air equivalent concentrations (the amount of a solute in cloud water per unit volume of air) were derived in order to eliminate concentration dependence on LWC and to allow comparison with previous aerosol, trace gas, and cloud water studies. The analysis indicates that background marine conditions were not always encountered during the DYCOMS-II mission as a result of anthropogenic or biogenic sources impacting the study region.

  4. Multiple metabolisms constrain the anaerobic nitrite budget in the Eastern Tropical South Pacific

    Science.gov (United States)

    Babbin, Andrew R.; Peters, Brian D.; Mordy, Calvin W.; Widner, Brittany; Casciotti, Karen L.; Ward, Bess B.

    2017-02-01

    The Eastern Tropical South Pacific is one of the three major oxygen deficient zones (ODZs) in the global ocean and is responsible for approximately one third of marine water column nitrogen loss. It is the best studied of the ODZs and, like the others, features a broad nitrite maximum across the low oxygen layer. How the microbial processes that produce and consume nitrite in anoxic waters interact to sustain this feature is unknown. Here we used 15N-tracer experiments to disentangle five of the biologically mediated processes that control the nitrite pool, including a high-resolution profile of nitrogen loss rates. Nitrate reduction to nitrite likely depended on organic matter fluxes, but the organic matter did not drive detectable rates of denitrification to N2. However, multiple lines of evidence show that denitrification is important in shaping the biogeochemistry of this ODZ. Significant rates of anaerobic nitrite oxidation at the ODZ boundaries were also measured. Iodate was a potential oxidant that could support part of this nitrite consumption pathway. We additionally observed N2 production from labeled cyanate and postulate that anammox bacteria have the ability to harness cyanate as another form of reduced nitrogen rather than relying solely on ammonification of complex organic matter. The balance of the five anaerobic rates measured—anammox, denitrification, nitrate reduction, nitrite oxidation, and dissimilatory nitrite reduction to ammonium—is sufficient to reproduce broadly the observed nitrite and nitrate profiles in a simple one-dimensional model but requires an additional source of reduced nitrogen to the deeper ODZ to avoid ammonium overconsumption.

  5. N2 fixation in eddies of the eastern tropical South Pacific Ocean

    Science.gov (United States)

    Loscher, Carolin R.; Bourbonnais, Annie; Dekaezemacker, Julien; Charoenpong, Chawalit N.; Altabet, Mark A.; Bange, Hermann W.; Czeschel, Rena; Hoffmann, Chris; Schmitz, Ruth

    2016-05-01

    Mesoscale eddies play a major role in controlling ocean biogeochemistry. By impacting nutrient availability and water column ventilation, they are of critical importance for oceanic primary production. In the eastern tropical South Pacific Ocean off Peru, where a large and persistent oxygen-deficient zone is present, mesoscale processes have been reported to occur frequently. However, investigations into their biological activity are mostly based on model simulations, and direct measurements of carbon and dinitrogen (N2) fixation are scarce.We examined an open-ocean cyclonic eddy and two anticyclonic mode water eddies: a coastal one and an open-ocean one in the waters off Peru along a section at 16° S in austral summer 2012. Molecular data and bioassay incubations point towards a difference between the active diazotrophic communities present in the cyclonic eddy and the anticyclonic mode water eddies.In the cyclonic eddy, highest rates of N2 fixation were measured in surface waters but no N2 fixation signal was detected at intermediate water depths. In contrast, both anticyclonic mode water eddies showed pronounced maxima in N2 fixation below the euphotic zone as evidenced by rate measurements and geochemical data. N2 fixation and carbon (C) fixation were higher in the young coastal mode water eddy compared to the older offshore mode water eddy. A co-occurrence between N2 fixation and biogenic N2, an indicator for N loss, indicated a link between N loss and N2 fixation in the mode water eddies, which was not observed for the cyclonic eddy. The comparison of two consecutive surveys of the coastal mode water eddy in November 2012 and December 2012 also revealed a reduction in N2 and C fixation at intermediate depths along with a reduction in chlorophyll by half, mirroring an aging effect in this eddy. Our data indicate an important role for anticyclonic mode water eddies in stimulating N2 fixation and thus supplying N offshore.

  6. Late quaternary sea bottom conditions in the southern Panama basin, Eastern Equatorial Pacific

    Science.gov (United States)

    Patarroyo, German D.; Martínez, José I.

    2015-11-01

    A paleoceanographic reconstruction of the southern Panama Basin for the last 23.000 years, based on the benthic foraminiferal analysis from the deep sea core ME0005A-24JC (0.01°N, 86.28°W, water depth 2941) is presented. Cluster and SHEBI (SHE Analysis for Biozone Identification) analyses performed on the benthic foraminiferal assemblages, evidence a faunal turnover in the early Holocene at 14 ky BP. Between 23 and 14 ky BP, Fursenkoina rotundata, Hoeglundina elegans, Globobulimina affinis, Globobulimina pacifica, Cibicidoides wuellerstorfi and Uvigerina hispidocostata were common. Conversely, from 14 ky to the present, the assemblage is represented by Chilostomella oolina, Laticarinina pauperata, and Uvigerina proboscidea. This faunal turnover suggests significant fluctuations in oxygen content at the sea floor and the organic matter (OM) influx, which could reflect: (1) fluctuations in the surface productivity related to the equatorial divergence and, (2) OM advection caused by the dynamic of the deep sea currents. Paleoproductivity estimates and benthic foraminiferal rates depict a general trend towards lower values since the Last Glacial Maximum (LGM) with a conspicuous change at 14 ky BP. Therefore, the paleoceanographic reconstructions of the ME0005A-24JC core suggest a transition from La Niña-like conditions during the LGM to El Niño-like conditions in the recent, as previously proposed for the Eastern Equatorial Pacific. Estimates of the paleo-intensity of deep sea currents based on the relative percentage abundance of the epifaunal foraminifera Cibicidoides wuellerstorfi suggest stronger deep sea currents on the Carnegie Ridge before 14 ky BP.

  7. The continental margin is a key source of iron to the HNLC North Pacific Ocean

    Energy Technology Data Exchange (ETDEWEB)

    Lam, P.J.; Bishop, J.K.B

    2008-01-15

    Here we show that labile particulate iron and manganese concentrations in the upper 500m of the Western Subarctic Pacific, an iron-limited High Nutrient Low Chlorophyll (HNLC) region, have prominent subsurface maxima between 100-200 m, reaching 3 nM and 600 pM, respectively. The subsurface concentration maxima in particulate Fe are characterized by a more reduced oxidation state, suggesting a source from primary volcagenic minerals such as from the Kuril/Kamchatka margin. The systematics of these profiles suggest a consistently strong lateral advection of labile Mn and Fe from redox-mobilized labile sources at the continental shelf supplemented by a more variable source of Fe from the upper continental slope. This subsurface supply of iron from the continental margin is shallow enough to be accessible to the surface through winter upwelling and vertical mixing, and is likely a key source of bioavailable Fe to the HNLC North Pacific.

  8. Clustering analysis of western North Pacific Tropical Cyclone tracks using the Self Organizing Map

    Science.gov (United States)

    Kim, H.; Seo, K.

    2013-12-01

    A cluster analysis using Self Organizing Map (SOM) is used to characterize tropical cyclone (TC) tracks over the western North Pacific. A False Discovery Rate (FDR) method is used to objectively determine an optimum cluster number. For 620 TC tracks over the WNP from June-October during 1979-2010, the five clusters for TC tracks are selected. These can further be categorized into three major patterns: straight-moving track, recurving track, and quasi-random pattern. Each pattern is characterized by land falling regions: near South and East China, East Asia, and off-shore of Japan. In addition, each pattern shows distinctive properties in its traveling distance, lifetime, intensity (mean minimum sea level pressure), and genesis location. It is revealed that these three patterns are associated with the large-scale dynamics such as variability of the western Pacific subtropical high and the Madden-Julian Oscillation. The impacts of El Nino and NAO will be discussed.

  9. Decadal variability in the occurrence of wintertime haze in central eastern China tied to the Pacific Decadal Oscillation

    Science.gov (United States)

    Zhao, Sen; Li, Jianping; Sun, Cheng

    2016-06-01

    Haze is a serious issue in China with increasing concerns, and understanding the factors driving decadal-scale variations in haze occurrence is relevant for government policymaking. Using a comprehensive observational haze dataset, we demonstrate notable decadal fluctuations in the number of haze days (HD) during winter in central eastern China, showing a decline since the mid-1980s. The leading mode of the wintertime HD features an increasing trend for 1959-2012 in eastern China, highly correlated with China’s gross domestic product (GDP) that represents increasing trend of pollutant emissions, and to a lesser extent meteorological factors. The second mode shows decadal variations in central eastern China associated with Pacific Decadal Oscillation (PDO). Observations and numerical simulations suggest that Mongolia High and corresponding descending motion tend to be enhanced (weakened) in central eastern China during the positive (negative) phase of PDO. With PDO shifting towards a negative phase, the weakened Mongolia High and ascending anomalies make the air unstable and conduce to the spread of pollutants, leading to the decline in the wintertime HD over central eastern China since the mid-1980s. Based on above physical mechanisms, a linear model based on PDO and GDP metrics provided a good fit to the observed HD.

  10. Decadal variability in the occurrence of wintertime haze in central eastern China tied to the Pacific Decadal Oscillation.

    Science.gov (United States)

    Zhao, Sen; Li, Jianping; Sun, Cheng

    2016-06-10

    Haze is a serious issue in China with increasing concerns, and understanding the factors driving decadal-scale variations in haze occurrence is relevant for government policymaking. Using a comprehensive observational haze dataset, we demonstrate notable decadal fluctuations in the number of haze days (HD) during winter in central eastern China, showing a decline since the mid-1980s. The leading mode of the wintertime HD features an increasing trend for 1959-2012 in eastern China, highly correlated with China's gross domestic product (GDP) that represents increasing trend of pollutant emissions, and to a lesser extent meteorological factors. The second mode shows decadal variations in central eastern China associated with Pacific Decadal Oscillation (PDO). Observations and numerical simulations suggest that Mongolia High and corresponding descending motion tend to be enhanced (weakened) in central eastern China during the positive (negative) phase of PDO. With PDO shifting towards a negative phase, the weakened Mongolia High and ascending anomalies make the air unstable and conduce to the spread of pollutants, leading to the decline in the wintertime HD over central eastern China since the mid-1980s. Based on above physical mechanisms, a linear model based on PDO and GDP metrics provided a good fit to the observed HD.

  11. ENSO signals on sea-surface salinity in the eastern tropical pacific ocean

    Directory of Open Access Journals (Sweden)

    1998-01-01

    types collected in the tropical Pacific are analyzed to assess the regional impacts of past (1972-1996 El Niño Southern Oscillation (ENSO events. Focus is made on the regional changes in sea-surface temperature and salinity. Commercial vessels were recently equipped with automated thermosalinographs which allows to monitor the location of salinity front along the Panama-Tahiti line, separating the Panama Gulf from the South Pacific water masses. The latitudinal change of the salinity front is well correlated with the latitudinal change of the ITCZ. Salinity distribution gives additional information on El-Niño development. How future real time SSS data might provide interesting information on the development of ENSO phenomenon in the eastern tropical Pacific area will be discussed.

  12. Latest Quaternary palaeoceanographic change in the eastern North Atlantic based upon a dinoflagellate cyst event ecostratigraphy

    Directory of Open Access Journals (Sweden)

    Rex Harland

    2016-05-01

    Full Text Available The analyses of dinoflagellate cyst records, from the latest Quaternary sediments recovered from DSDP Core 610A taken on the Feni Ridge in the southern Rockall Trough, and part of core MD01-2461 on the continental margin of the Porcupine Seabight in the eastern North Atlantic Ocean, has provided evidence for significant oceanographic change encompassing the Last Glacial Maximum (LGM and part of the Holocene. This together with other published records has led to a regional evaluation of oceanographic change in the eastern North Atlantic over the past 68 ka, based upon a distinctive dinoflagellate event ecostratigraphy. These changes reflect changes in the surface waters of the North Atlantic Current (NAC, and perhaps the deeper thermohaline Atlantic Meridional Overturning Circulation (AMOC, driving fundamental regime changes within the phytoplanktonic communities. Three distinctive dinoflagellate cyst associations based upon both factor and cluster analyses have been recognised. Associations characterised by Bitectatodinium tepikiense (between 61.1 ± 6.2 to 13.4 ± 1.1 ka BP, Nematosphaeropsis labyrinthus (between 10.5 ± 0.3 and 11.45 ± 0.8 ka. BP, and the cyst of Protoceratium reticulatum (between 8.5 ± 0.9 and 5.2 ± 1.3 ka. BP indicate major change within the eastern North Atlantic oceanography. The transitions between these changes occur over a relatively short time span (c.1.5 ka, given our sampling resolution, and have the potential to be incorporated into an event stratigraphy through the latest Quaternary as recommended by the INTIMATE (INTegrating Ice core, MArine and TErrestrial records group. The inclusion of a dinoflagellate cyst event stratigraphy would highlight changes within the phytoplankton of the North Atlantic Ocean as a fully glacial world changed to our present interglacial.

  13. Latest Quaternary palaeoceanographic change in the eastern North Atlantic based upon a dinoflagellate cyst event ecostratigraphy.

    Science.gov (United States)

    Harland, Rex; Polovodova Asteman, Irina; Morley, Audrey; Morris, Angela; Harris, Anthony; Howe, John A

    2016-05-01

    The analyses of dinoflagellate cyst records, from the latest Quaternary sediments recovered from DSDP Core 610A taken on the Feni Ridge in the southern Rockall Trough, and part of core MD01-2461 on the continental margin of the Porcupine Seabight in the eastern North Atlantic Ocean, has provided evidence for significant oceanographic change encompassing the Last Glacial Maximum (LGM) and part of the Holocene. This together with other published records has led to a regional evaluation of oceanographic change in the eastern North Atlantic over the past 68 ka, based upon a distinctive dinoflagellate event ecostratigraphy. These changes reflect changes in the surface waters of the North Atlantic Current (NAC), and perhaps the deeper thermohaline Atlantic Meridional Overturning Circulation (AMOC), driving fundamental regime changes within the phytoplanktonic communities. Three distinctive dinoflagellate cyst associations based upon both factor and cluster analyses have been recognised. Associations characterised by Bitectatodinium tepikiense (between 61.1 ± 6.2 to 13.4 ± 1.1 ka BP), Nematosphaeropsis labyrinthus (between 10.5 ± 0.3 and 11.45 ± 0.8 ka. BP), and the cyst of Protoceratium reticulatum (between 8.5 ± 0.9 and 5.2 ± 1.3 ka. BP) indicate major change within the eastern North Atlantic oceanography. The transitions between these changes occur over a relatively short time span (c.1.5 ka), given our sampling resolution, and have the potential to be incorporated into an event stratigraphy through the latest Quaternary as recommended by the INTIMATE (INTegrating Ice core, MArine and TErrestrial records) group. The inclusion of a dinoflagellate cyst event stratigraphy would highlight changes within the phytoplankton of the North Atlantic Ocean as a fully glacial world changed to our present interglacial.

  14. INTERDECADAL VARIATIONS OF INTERACTION BETWEEN NORTH PACIFIC SSTA AND EAST ASIAN SUMMER MONSOON

    Institute of Scientific and Technical Information of China (English)

    李峰; 何金海

    2001-01-01

    Identification of key SST zones is essential in predicting the weather / climate systems in East Asia. With the SST data by the U.K. Meteorological Office and 40-year geopotential height and wind fields by NCAR / NCEP, the relationship between the East Asian summer monsoon and north Pacific SSTA is studied, which reveals their interactions are of interdecadal variation. Before mid-1970's, the north Pacific SSTA acts upon the summer monsoon in East Asia through a great circle wavetrain and results in more rainfall in the summer of the northern part of China. After 1976, the SSTA weakens the wavetrain and no longer influences the precipitation in North China due to loosened links with the East Asian summer monsoon. It can be drawn that the key SST zones having potential effects on the weather / climate systems in East Asia do not stay in one particular area of the ocean but rather shift elsewhere as governed by the interdecadal variations of the air-sea interactions. It is hoped that the study would help shed light on the prediction of drought / flood spans in China.

  15. A model of loggerhead sea turtle (Caretta caretta) habitat and movement in the oceanic North Pacific.

    Science.gov (United States)

    Abecassis, Melanie; Senina, Inna; Lehodey, Patrick; Gaspar, Philippe; Parker, Denise; Balazs, George; Polovina, Jeffrey

    2013-01-01

    Habitat preferences for juvenile loggerhead turtles in the North Pacific were investigated with data from two several-year long tagging programs, using 224 satellite transmitters deployed on wild and captive-reared turtles. Animals ranged between 23 and 81 cm in straight carapace length. Tracks were used to investigate changes in temperature preferences and speed of the animals with size. Average sea surface temperatures along the tracks ranged from 18 to 23 °C. Bigger turtles generally experienced larger temperature ranges and were encountered in warmer surface waters. Seasonal differences between small and big turtles suggest that the larger ones dive deeper than the mixed layer and subsequently target warmer surface waters to rewarm. Average swimming speeds were under 1 km/h and increased with size for turtles bigger than 30 cm. However, when expressed in body lengths per second (bl s(-1)), smaller turtles showed much higher swimming speeds (>1 bl s (-1) ) than bigger ones (0.5 bl s(-1)). Temperature and speed values at size estimated from the tracks were used to parameterize a habitat-based Eulerian model to predict areas of highest probability of presence in the North Pacific. The model-generated habitat index generally matched the tracks closely, capturing the north-south movements of tracked animals, but the model failed to replicate observed east-west movements, suggesting temperature and foraging preferences are not the only factors driving large-scale loggerhead movements. Model outputs could inform potential bycatch reduction strategies.

  16. A Model of Loggerhead Sea Turtle (Caretta caretta) Habitat and Movement in the Oceanic North Pacific

    Science.gov (United States)

    Abecassis, Melanie; Senina, Inna; Lehodey, Patrick; Gaspar, Philippe; Parker, Denise; Balazs, George; Polovina, Jeffrey

    2013-01-01

    Habitat preferences for juvenile loggerhead turtles in the North Pacific were investigated with data from two several-year long tagging programs, using 224 satellite transmitters deployed on wild and captive-reared turtles. Animals ranged between 23 and 81 cm in straight carapace length. Tracks were used to investigate changes in temperature preferences and speed of the animals with size. Average sea surface temperatures along the tracks ranged from 18 to 23 °C. Bigger turtles generally experienced larger temperature ranges and were encountered in warmer surface waters. Seasonal differences between small and big turtles suggest that the larger ones dive deeper than the mixed layer and subsequently target warmer surface waters to rewarm. Average swimming speeds were under 1 km/h and increased with size for turtles bigger than 30 cm. However, when expressed in body lengths per second (bl s−1), smaller turtles showed much higher swimming speeds (>1 bl s−1) than bigger ones (0.5 bl s−1). Temperature and speed values at size estimated from the tracks were used to parameterize a habitat-based Eulerian model to predict areas of highest probability of presence in the North Pacific. The model-generated habitat index generally matched the tracks closely, capturing the north-south movements of tracked animals, but the model failed to replicate observed east-west movements, suggesting temperature and foraging preferences are not the only factors driving large-scale loggerhead movements. Model outputs could inform potential bycatch reduction strategies. PMID:24039901

  17. A modified method to estimate eddy diffusivity in the North Pacific using altimeter eddy statistics

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhiwei; LI Yaru; TIAN Jiwei

    2013-01-01

    The method proposed by Stammer (1998) is modified using eddy statistics from altimeter observation to obtain more realistic eddy diffusivity (K) for the North Pacific.Compared with original estimates,the modified K has remarkably reduced values in the Kuroshio Extension (KE) and North Equatorial Counter Current (NECC) regions,but slightly enhanced values in the Subtropical Counter Current (STCC) region.In strong eastward flow areas like the KE and NECC,owing to a large difference between mean flow velocity and propagation velocity of mesoscale eddies,tracers inside the mesoscale eddies are transported outside rapidly by advection,and mixing length L is hence strongly suppressed.The low eddy probability (P) is also responsible for the reduced K in the NECC area.In the STCC region,however,L is mildly suppressed and P is very high,so K there is enhanced.The zonally-averaged K has two peaks with comparable magnitudes,in the latitude bands of the STCC and KE.In the core of KE,because of the reduced values of P and L,the zonally-averaged K is a minimum.Zonally-integrated eddy heat transport in the KE band,calculated based on the modified K,is much closer to the results of previous independent research,indicating the robustness of our modified K.The map of modified K provides useful information for modeling studies in the North Pacific.

  18. A model of loggerhead sea turtle (Caretta caretta habitat and movement in the oceanic North Pacific.

    Directory of Open Access Journals (Sweden)

    Melanie Abecassis

    Full Text Available Habitat preferences for juvenile loggerhead turtles in the North Pacific were investigated with data from two several-year long tagging programs, using 224 satellite transmitters deployed on wild and captive-reared turtles. Animals ranged between 23 and 81 cm in straight carapace length. Tracks were used to investigate changes in temperature preferences and speed of the animals with size. Average sea surface temperatures along the tracks ranged from 18 to 23 °C. Bigger turtles generally experienced larger temperature ranges and were encountered in warmer surface waters. Seasonal differences between small and big turtles suggest that the larger ones dive deeper than the mixed layer and subsequently target warmer surface waters to rewarm. Average swimming speeds were under 1 km/h and increased with size for turtles bigger than 30 cm. However, when expressed in body lengths per second (bl s(-1, smaller turtles showed much higher swimming speeds (>1 bl s (-1 than bigger ones (0.5 bl s(-1. Temperature and speed values at size estimated from the tracks were used to parameterize a habitat-based Eulerian model to predict areas of highest probability of presence in the North Pacific. The model-generated habitat index generally matched the tracks closely, capturing the north-south movements of tracked animals, but the model failed to replicate observed east-west movements, suggesting temperature and foraging preferences are not the only factors driving large-scale loggerhead movements. Model outputs could inform potential bycatch reduction strategies.

  19. Occurrence of perfluoroalkyl compounds in surface waters from the North Pacific to the Arctic Ocean.

    Science.gov (United States)

    Cai, Minghong; Zhao, Zhen; Yin, Zhigao; Ahrens, Lutz; Huang, Peng; Cai, Minggang; Yang, Haizhen; He, Jianfeng; Sturm, Renate; Ebinghaus, Ralf; Xie, Zhiyong

    2012-01-17

    Perfluoroalkyl compounds (PFCs) were determined in 22 surface water samples (39-76°N) and three sea ice core and snow samples (77-87°N) collected from North Pacific to the Arctic Ocean during the fourth Chinese Arctic Expedition in 2010. Geographically, the average concentration of ∑PFC in surface water samples were 560 ± 170 pg L(-1) for the Northwest Pacific Ocean, 500 ± 170 pg L(-1) for the Arctic Ocean, and 340 ± 130 pg L(-1) for the Bering Sea, respectively. The perfluoroalkyl carboxylates (PFCAs) were the dominant PFC class in the water samples, however, the spatial pattern of PFCs varied. The C(5), C(7) and C(8) PFCAs (i.e., perfluoropentanoate (PFPA), perfluoroheptanoate (PFHpA), and perfluorooctanoate (PFOA)) were the dominant PFCs in the Northwest Pacific Ocean while in the Bering Sea the PFPA dominated. The changing in the pattern and concentrations in Pacific Ocean indicate that the PFCs in surface water were influenced by sources from the East-Asian (such as Japan and China) and North American coast, and dilution effect during their transport to the Arctic. The presence of PFCs in the snow and ice core samples indicates an atmospheric deposition of PFCs in the Arctic. The elevated PFC concentration in the Arctic Ocean shows that the ice melting had an impact on the PFC levels and distribution. In addition, the C(4) and C(5) PFCAs (i.e., perfluorobutanoate (PFBA), PFPA) became the dominant PFCs in the Arctic Ocean indicating that PFBA is a marker for sea ice melting as the source of exposure.

  20. Mercury in tunas and blue marlin in the North Pacific Ocean.

    Science.gov (United States)

    Drevnick, Paul E; Brooks, Barbara A

    2017-03-06

    Models and data from the North Pacific Ocean indicate that mercury concentrations in water and biota are increasing in response to (global or hemispheric) anthropogenic mercury releases. In the present study, we provide an updated record of mercury in yellowfin tuna (Thunnus albacares) caught near Hawaii that confirms an earlier conclusion that mercury concentrations in these fish are increasing at a rate similar to that observed in waters shallower than 1000 m. We also compiled and reanalyzed data from bigeye tuna (Thunnus obesus) and blue marlin (Makaira nigricans) caught near Hawaii in the 1970s and 2000s. Increases in mercury concentrations in bigeye tuna are consistent with the trend found in yellowfin tuna, in both timing and magnitude. The data available for blue marlin do not allow for a fair comparison among years, because mercury concentrations differ between sexes for this species, and sex was identified (or reported) in only 3 of 7 studies. Also, mercury concentrations in blue marlin may be insensitive to modest changes in mercury exposure, because this species appears to have the ability to detoxify mercury. The North Pacific Ocean is a region of both relatively high rates of atmospheric mercury deposition and capture fisheries production. Other data sets that allow temporal comparisons in mercury concentrations, such as pacific cod (Gadus macrocephalus) in Alaskan waters and albacore tuna (Thunnus alalunga) off the US Pacific coast, should be explored further, to aid in understanding human health and ecological risks and to develop additional baseline knowledge for assessing changes in a region expected to respond strongly to reductions in anthropogenic mercury emissions. Environ Toxicol Chem 2016;9999:1-10. © 2017 SETAC.

  1. Landslide hazard prediction in the North-Eastern Apennines (Italy)

    Science.gov (United States)

    Disperati, L.; Guastaldi, E.; Rindinella, A.

    2003-04-01

    In order to assess the landslide hazard nearby the Pergola city (in the Northern-Eastern Apennines, Italy) a ground survey at a scale of 1:10,000 was performed for an extent of about 370 km^2 (Carmignani, 2001), and a GIS of landslides was built. Following statistical analysis allows to assess the correlation among landslide occurrences and causal factors related to the detachment zone (lithology, engineering geology, elevation, slope, aspect, bedding as related with slope face -RBS- and land use). Consequently, considering the morphological, lithological and anthropic characters of current slides, it was agreed to locate possible future landslides in those area actually stable but characterised by similar conditions. Because of that, a geostatistical analysis was performed. Comparing for every landslide the occurence of either single or combined causal factor, the analysis was carried out in grid format. The spatial analysis of the GIS data layers allowed building the unique condition regions (Chung et al., 1995) and creating statistical data on causal factors in relation of landslides. Afterwards, for every region the susceptibility to development of new occurrences (favourability mapping) was calculated by utilising the certainty factor (CF; Chung &Fabbri, 1993). For landslides where crown was identified, the main scarp was considered as occurrence; a buffer around the highest point of landslide was built for all the others (Disperati et al., 2002). Such procedure was applied both for slides (175 occurrences) and flows (464 occurrences). Furthermore, by the application of the procedure to causal factors and their combination, additional information regarding susceptibility to development of new occurrences was calculated. The selection of the most suitable factors combination can be done through the results accuracy assessment in relation of time and/or space (Chung, 1999), by utilising two different hazard information layers, respectively computed from a

  2. A 290-a record of atmospheric circulation over the North Pacific from a Mt. Logan ice core, Yukon Territory

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Calibrations between sodium (Na+) concentrations from a Mt. Logan ice core and sea level pressure (SLP) series show that Na+ concentrations are closely correlated with the autumn-time (SeptemberOctober-November) Aleutian low (AleuLow). A deepening of the AleuLow strengthens the transport of sea-salt aerosols from the North Pacific to the Mt. Logan region. The Mt. Logan Na+ record is used to develop a 292 a (1688~1979) reconstruction of the AleuLow revealing a dramatic intensification of atmospheric circulation over the North Pacific region since the 20th century. Mean SLP of the AleuLow was about 1 hPa lower during the 20th century than during prior periods. The strongest deepening of the AleuLow appeared in the 1950s. Significant correlations are also found between the Mt. Logan AleuLow proxy series and the Pacific decadal oscillation (PDO) and Pacific circulation (PC) index during the 20th century. Evolutionary spectral analysis of the proxy record shows significant periodicities from 15 to 30 a consistent with PDO fluctuations and the bidecadal oscillation of North Pacific atmosphere-ocean circulation. A period of 11 a in the AleuLow record may be associated with the Schwabe 11-a cycle of sunspot activity. Additional longer ice core records from this region will aid in the efforts to further understand the climatic change over the North Pacific region.

  3. NON-ZONAL BAROCLINIC INSTABILITY IN THE NORTH PACIFIC SUBTROPICAL COUNTERCURRENT

    Institute of Scientific and Technical Information of China (English)

    LU Yan; LUO De-hai

    2004-01-01

    Observations indicated that in the region of the Subtropical Countercurrent(STCC)over the Pacific(140°E-170°W,19°N-28°N),the eddy kinetic energy over the western side is much higher than that over the eastern side.The cause of such a behavior was theoretically investigated in this paper.The calculation of geostrophic current in this region indicates that there are relatively strong meridional geostrophic currents in this region even though the zonal current is dominant in most seasons.Using a 2.5-layer reduced-gravity model,baroclinic instability of non-zonal current was discussed.It is found that at the western side of STCC the vertical shear of the meridional geostrophic current will be in favor of the baroclinic instability,but at its eastern side it will suppress baroclinic instability,thus causing the growth of eddies over the western side much faster than that over the eastern side.

  4. A new centennial index to study the Western North Pacific Monsoon decadal variability

    Science.gov (United States)

    Vega, Inmaculada; Gómez-Delgado, F. de Paula; Gallego, David; Ribera, Pedro; Peña-Ortiz, Cristina; García-Herrera, Ricardo

    2016-04-01

    The concept of the Western North Pacific Summer Monsoon (WNPSM) appeared for the first time in 1987. It is, unlike the Indian Summer Monsoon (ISM) and the East Asian summer monsoon (EASM), an oceanic monsoon mostly driven by the meridional gradient of sea surface temperature. Its circulation is characterized by a northwest-southeast oriented monsoon trough with intense precipitation and low-level southwesterlies and upper-tropospheric easterlies in the region [100°-130° E, 5°-15°N]. Up to now, the primary index to characterize the WNPSM has been the Western North Pacific Monsoon Index (WNPMI) which covers the 1949-2013 period. The original WNPMI was defined as the difference of 850-hPa westerlies between two regions: D1 [5°-15°N, 100°-130°E] and D2 [20°-30°N, 110°-140°E]. Both domains are included in the main historical ship routes circumnavigating Asia for hundreds of years. Many of the logbooks of these ships have been preserved in historical archives and they usually contain daily observations of wind force and direction. Therefore, it has been possible to compute a new index of instrumental character, which reconstructs the WNPSM back to the middle of the 19th Century, by using solely historical wind direction records preserved in logbooks. We define the monthly Western North Pacific Directional Index (WNPDI) as the sum of the persistence of the low-level westerly winds in D1 and easterly winds in D2. The advantages of this new index are its nature (instrumental) and its length (1849-2013), which is 100 years longer than the WNPMI (which was based on reanalysis data). Our WNPDI shows a high correlation (r=+0.87, pCompetitividad through the project INCITE (CGL2013-44530-P, BES-2014-069733).

  5. Structure and dynamics of decadal anomalies in the wintertime midlatitude North Pacific ocean-atmosphere system

    Science.gov (United States)

    Fang, Jiabei; Yang, Xiu-Qun

    2016-09-01

    The structure and dynamics of decadal anomalies in the wintertime midlatitude North Pacific ocean-atmosphere system are examined in this study, using the NCEP/NCAR atmospheric reanalysis, HadISST SST and Simple Ocean Data Assimilation data for 1960-2010. The midlatitude decadal anomalies associated with the Pacific Decadal Oscillation are identified, being characterized by an equivalent barotropic atmospheric low (high) pressure over a cold (warm) oceanic surface. Such a unique configuration of decadal anomalies can be maintained by an unstable ocean-atmosphere interaction mechanism in the midlatitudes, which is hypothesized as follows. Associated with a warm PDO phase, an initial midlatitude surface westerly anomaly accompanied with intensified Aleutian low tends to force a negative SST anomaly by increasing upward surface heat fluxes and driving southward Ekman current anomaly. The SST cooling tends to increase the meridional SST gradient, thus enhancing the subtropical oceanic front. As an adjustment of the atmospheric boundary layer to the enhanced oceanic front, the low-level atmospheric meridional temperature gradient and thus the low-level atmospheric baroclinicity tend to be strengthened, inducing more active transient eddy activities that increase transient eddy vorticity forcing. The vorticity forcing that dominates the total atmospheric forcing tends to produce an equivalent barotropic atmospheric low pressure north of the initial westerly anomaly, intensifying the initial anomalies of the midlatitude surface westerly and Aleutian low. Therefore, it is suggested that the midlatitude ocean-atmosphere interaction can provide a positive feedback mechanism for the development of initial anomaly, in which the oceanic front and the atmospheric transient eddy are the indispensable ingredients. Such a positive ocean-atmosphere feedback mechanism is fundamentally responsible for the observed decadal anomalies in the midlatitude North Pacific ocean

  6. Transformation from Paleo-Asian Ocean closure to Paleo-Pacific subduction: New constraints from granitoids in the eastern Jilin-Heilongjiang Belt, NE China

    Science.gov (United States)

    Ma, Xing-Hua; Zhu, Wen-Ping; Zhou, Zhen-Hua; Qiao, Shi-Lei

    2017-08-01

    The eastern Jilin-Heilongjiang Belt (EJHB) of NE China is a unique orogen that underwent two stages of evolution within the tectonic regimes of the Paleo-Asian and Paleo-Pacific oceans. 158 available zircon U-Pb ages, including 26 ages obtained during the present study and 132 ages from the literature, were compiled and analyzed for the Mesozoic and Cenozoic granitoids from the EJHB and the adjacent Russian Sikhote-Alin Orogenic Belt (SAOB), to examine the temporal-spatial distribution of the granitoids and to constrain the tectonic evolution of the East Asian continental margin. Five stages of granitic magmatism can be identified: Early Triassic (251-240 Ma), Late Triassic (228-215 Ma), latest Triassic to Middle Jurassic (213-158 Ma), Early Cretaceous (131-105 Ma), and Late Cretaceous to Paleocene (95-56 Ma). The Early Triassic granitoids are restricted to the Yanbian region along the Changchun-Yanji Suture, and show geochemical characteristics of magmas from a thickened lower crust source, probably due to the final collision of the combined NE China blocks with the North China Craton. The Late Triassic granitoids, with features of A-type granites, represent post-collisional magmatic activities that were related to post-orogenic extension, marking the end of the tectonic evolution of the Paleo-Asian Ocean. The latest Triassic to Paleocene granitoids with calc-alkaline characteristics were NE-trending emplaced along the EJHB and SAOB and young towards the coastal region, and represent continental marginal arc magmas that were associated with the northwestwards subduction of the Paleo-Pacific Plate. Two periods of magmatic quiescence (158-131 and 105-95 Ma) correspond to changes in the subduction direction of the Paleo-Pacific Plate from oblique relative to the continental margin to subparallel. Taking all this into account, we conclude that: (1) the final closure of the Paleo-Asian Ocean occurred along the Changchun-Yanji Suture during the Early Triassic; (2) the

  7. Interdecadal variability of the tropospheric biennial oscillation in the western North Pacific

    Institute of Scientific and Technical Information of China (English)

    Zheng Bin; Lin Ai-Lan; Gu De-Jun; Li Chun-Hui

    2008-01-01

    The observed tropospheric biennial oscillation (TBO) in the western North Pacific (WNP) monsoon region has an interdecadal variability with a period of 40-50 yr.That suggests a weaker effect of the TBO on the East Asia followed by a stronger one.A simple analytic model was designed to investigate the mechanism of the interdecadal variability of the TBO.The results indicated that a local TBO air-sea system not only supports the TBO variability in the WNP monsoon region but also produces an interdecadal variability of the TBO.

  8. Seasonal variation of atmospheric Pb-210 and Al in the western North Pacific region

    Science.gov (United States)

    Tsunogai, Shizuo; Kurata, Takayoshi; Suzuki, Toshitaka; Yokota, Kiichiro

    1988-11-01

    The atmospheric concentrations of Pb-210 over a period of two years were determined from aerosol samples collected at six stations in the western North Pacific. The results are compared with those for Al, showing that, although Pb-210 concentrations vary widely from week to week, the degree of variation is about half of that for Al. For Pb-210, the year-to-year variation is not pronounced and the seasonal variation is well represented by a sine curve. The results suggest that Pb-210 has a longer residence time than Al, because Pb-210 is transported through higher altitudes and is deposited more evenly onto the earth's surface and the ocean.

  9. Food-web inferences of stable isotope spatial patterns in copepods and yellowfin tuna in the pelagic eastern Pacific Ocean

    Science.gov (United States)

    Olson, Robert J.; Popp, Brian N.; Graham, Brittany S.; López-Ibarra, Gladis A.; Galván-Magaña, Felipe; Lennert-Cody, Cleridy E.; Bocanegra-Castillo, Noemi; Wallsgrove, Natalie J.; Gier, Elizabeth; Alatorre-Ramírez, Vanessa; Ballance, Lisa T.; Fry, Brian

    2010-07-01

    Evaluating the impacts of climate and fishing on oceanic ecosystems requires an improved understanding of the trophodynamics of pelagic food webs. Our approach was to examine broad-scale spatial relationships among the stable N isotope values of copepods and yellowfin tuna ( Thunnus albacares), and to quantify yellowfin tuna trophic status in the food web based on stable-isotope and stomach-contents analyses. Using a generalized additive model fitted to abundance-weighted-average δ 15N values of several omnivorous copepod species, we examined isotopic spatial relationships among yellowfin tuna and copepods. We found a broad-scale, uniform gradient in δ 15N values of copepods increasing from south to north in a region encompassing the eastern Pacific warm pool and parts of several current systems. Over the same region, a similar trend was observed for the δ 15N values in the white muscle of yellowfin tuna caught by the purse-seine fishery, implying limited movement behavior. Assuming the omnivorous copepods represent a proxy for the δ 15N values at the base of the food web, the isotopic difference between these two taxa, “ ΔYFT-COP,” was interpreted as a trophic-position offset. Yellowfin tuna trophic-position estimates based on their bulk δ 15N values were not significantly different than independent estimates based on stomach contents, but are sensitive to errors in the trophic enrichment factor and the trophic position of copepods. An apparent inshore-offshore, east to west gradient in yellowfin tuna trophic position was corroborated using compound-specific isotope analysis of amino acids conducted on a subset of samples. The gradient was not explained by the distribution of yellowfin tuna of different sizes, by seasonal variability at the base of the food web, or by known ambit distances (i.e. movements). Yellowfin tuna stomach contents did not show a regular inshore-offshore gradient in trophic position during 2003-2005, but the trophic

  10. Temporal size changes of Miocene planktonic foraminifera Paragloborotalia siakensis in the eastern Equatorial Pacific associated with Mi-events

    Science.gov (United States)

    Okada, H.; Hayashi, H.

    2013-12-01

    Temporal changes in test size of planktonic foraminifera have been variously studied as a key for knowing evolution related to paleoceanographic changes. With respect to recent studies, rapid size reducing ('dwarfing') in several species have been observed around the last occurrence horizon. Generically, size changes of calcareous nannofossils have been used for global correlation. However, there are few previous studies of such temporal size changes for Miocene planktonic foraminifera. Paragloborotalia siakensis (LeRoy, 1939) is one of important index species in the middle Miocene. The upper boundary of planktonic foraminieral Zone N.14 is defined by the top occurrence of this species. It is a well known fact that P. siakensis is a dominant species in the tropical high-productivity area such as the eastern equatorial Pacific. The aims of this study are to reveal size changes of P. siakensis collected from IODP Site U1338 in the eastern equatorial Pacific and to correlate the size changes with paleoceanographic events. We measured maximum length of P. siakensis (50-200 individuals for each horizon) at approximately every 0.1 million years from 16.0 to 10.5 Ma. At the same time, we also conducted morphometric analyses of selected five horizons (14.96 Ma, 14.03 Ma, 13.00 Ma, 12.29 Ma and 11.11 Ma) by means of image analysis software (ImageJ). According to the morphometric analyses, the population from Site U1338 should be compared with the holotype of P. siakensis. The maximum length of P. siakensis shows significant reducing ('dwarfing') at cooling intervals inferred by previous studies based on alkenone and isotope data. It is possible to say that dwarfing of P. siakensis at Site U1338 might be induced by shallowing of the thermocline in the eastern equatorial Pacific.

  11. Role of the oceanic bridge in linking the 18.6 year modulation of tidal mixing and long-term SST change in the North Pacific

    Science.gov (United States)

    Osafune, S.; Masuda, S.; Sugiura, N.

    2014-10-01

    The impact of the 18.6 year modulation of tidal mixing on sea surface temperature (SST) in the North Pacific is investigated in a comparative study using an ocean data synthesis system. We show that remote impact through a slow ocean response can make a significant contribution to the observed bidecadal variation in wintertime SST near the center of action of the Pacific Decadal Oscillation in the eastern Pacific. A comparative data synthesis experiment showed that the modified SST variation is amplified by bidecadal variation in the westerly wind. This relationship between SST and wind variations is consistent with an observed air-sea coupled mode in the extratropics, which suggests that a midlatitude air-sea interaction plays an important role in enhancing the climate signal of the 18.6 year modulation. This result supports the hypothesis that the 18.6 year tidal cycle influences long-term variability in climate; thus, knowledge of this cycle could contribute toward improving decadal predictions of climate.

  12. Three-Dimensional Structure and Low-Level Features of the North Pacific Storm Track from 1999 to 2005

    Institute of Scientific and Technical Information of China (English)

    FU Gang; BI Wei; GUO Jingtian

    2009-01-01

    A storm track is a region in which synoptic eddy activities are statistically most prevalent and intense. At daily weather charts, it roughly corresponds to the mean trajectories of cyclones and anticyclones. In this paper, the recent QuikSCAT (Quick Scatterometer) satellite sea winds data with a 0.5°×0.5° horizontal resolution, and the NCEP (National Centers for Environmental Prediction) 10-m height Gaussian grid wind data and pressure-level reanalysis data, are employed to document the spatial structure of the North Pacific storm track in winter (January) and summer (July) from 1999 to 2005. The results show that in winter the North Pacific storm track is stronger, and is located in lower latitudes with a distinct zonal distribution. In summer, it is weaker, and is located in higher latitudes. Based on the horizontal distributions of geopotential height variance at various levels, three-dimensional schematic diagrams of the North Pacific storm track in winter and summer are extracted and presented. Analyses of the QuikSCAT wind data indicate that this dataset can depict the low-level storm track features in detail. The double storm tracks over the Southern Oceans found by Nakamura and Shimpo are confirmed. More significantly, two new pairs of low-level storm tracks over the North Pacific and the North Atlantic are identified by using this high-resolution dataset. The pair over the North Pacific is focused in this paper, and is named as the "subtropical storm track" and the "subpolar storm track", respectively. Moreover, statistical analyses of cyclone and anticyclone trajectories in the winters of 1999 to 2005 reveal as well the existence of the low-level double storm tracks over the North Pacific.

  13. Health risk assessment from mercury levels in bycatch fish species from the coasts of Guerrero, Mexico (Eastern Pacific).

    Science.gov (United States)

    Spanopoulos-Zarco, P; Ruelas-Inzunza, J; Meza-Montenegro, M; Osuna-Sánchez, K; Amezcua-Martínez, F

    2014-09-01

    With the aim of determining Hg distribution in muscle and liver of bycatch fish from Guerrero state in the Eastern Pacific Ocean and assess the potential risk to consumer, Hg was quantified in 14 species of bycatch fish. For the majority of fish the order of Hg levels was liver > muscle. The highest concentration corresponded to the liver of Isopisthus remifer (2.05 µg g(-1)) and the lowest (0.02 µg g(-1)) was detected in muscle of Prionotus sp. The highest hazard quotient (0.75) was found in the Mexican milkfish Micropogonias ectenes; considering all the individuals, mean hazard quotient was 0.336.

  14. Conditions of the occurrence of Anemone sylvestris in a kettle hole in north-eastern Poland

    Directory of Open Access Journals (Sweden)

    Anna J. Kwiatkowska-Falińska

    2011-04-01

    Full Text Available The research, in 2004, was focused on the whole population of Anemone sylvestris (Snowdrop Windflower present in the area of a kettle hole (0.8 km2 in north-eastern Poland (52°50’00’’N; 23°11’20’’E. The location of 56 clumps of generative specimens was surveyed. They numbered from several to approx. 1500 specimens. The number of generative specimens in this population exceeded 10 000. On account of this, it is a unique stand of A. sylvestris in Poland. The relationship between the occurrence of the Snowdrop Windflower and the presence of kame hills and ridges has been proven. Low slopes of kame with an inclination of 10-20o, and a north-eastern or eastern exposition has been found as the local ecological optimum for this species. Research carried out in 1970-2001 on 5 permanent plots (25 m2 each has shown that: 1 Anemone sylvestris is an essential element of xerothermic grasslands of the order Festucetalia valesiacae; 2 the species suddenly withdraws from the parts of land on which woody species have already reached the shrub layer; 3 the greatest danger for the population of A. sylvestris in this area is the process of secondary succession initiated by the discontinuation of grazing on the kame hills.

  15. Biogeochemical characteristics of a long-lived anticyclonic eddy in the eastern South Pacific Ocean

    Science.gov (United States)

    Cornejo D'Ottone, Marcela; Bravo, Luis; Ramos, Marcel; Pizarro, Oscar; Karstensen, Johannes; Gallegos, Mauricio; Correa-Ramirez, Marco; Silva, Nelson; Farias, Laura; Karp-Boss, Lee

    2016-05-01

    Mesoscale eddies are important, frequent, and persistent features of the circulation in the eastern South Pacific (ESP) Ocean, transporting physical, chemical and biological properties from the productive shelves to the open ocean. Some of these eddies exhibit subsurface hypoxic or suboxic conditions and may serve as important hotspots for nitrogen loss, but little is known about oxygen consumption rates and nitrogen transformation processes associated with these eddies. In the austral fall of 2011, during the Tara Oceans expedition, an intrathermocline, anticyclonic, mesoscale eddy with a suboxic (Water (ESSW) that at this latitude is normally restricted to an area near the coast. Measurements of nitrogen species within the eddy revealed undersaturation (below 44 %) of nitrous oxide (N2O) and nitrite accumulation (> 0.5 µM), suggesting that active denitrification occurred in this water mass. Using satellite altimetry, we were able to track the eddy back to its region of formation on the coast of central Chile (36.1° S, 74.6° W). Field studies conducted in Chilean shelf waters close to the time of eddy formation provided estimates of initial O2 and N2O concentrations of the ESSW source water in the eddy. By the time of its offshore sighting, concentrations of both O2 and N2O in the subsurface oxygen minimum zone (OMZ) of the eddy were lower than concentrations in surrounding water and "source water" on the shelf, indicating that these chemical species were consumed as the eddy moved offshore. Estimates of apparent oxygen utilization rates at the OMZ of the eddy ranged from 0.29 to 44 nmol L-1 d-1 and the rate of N2O consumption was 3.92 nmol L-1 d-1. These results show that mesoscale eddies affect open-ocean biogeochemistry in the ESP not only by transporting physical and chemical properties from the coast to the ocean interior but also during advection, local biological consumption of oxygen within an eddy further generates conditions favorable to

  16. Rain ratio variation in the Tropical Ocean: Tests with surface sediments in the eastern equatorial Pacific

    Science.gov (United States)

    Mekik, Figen; Loubere, Paul; Richaud, Mathieu

    2007-03-01

    The organic carbon to calcite flux ratio (rain ratio) has a profound effect on the preservation of carbonates in the deep sea and may influence atmospheric pCO 2 over millennia. Unfortunately, the degree to which the rain ratio varies in the more productive regions of the oceans is not well determined with sediment trap data. The rain ratio in the upper ocean appears dominantly linked to diatom productivity, which is not necessarily directly linked to total production and may be regionally variable. However, ballasting and protection of organic carbon by calcareous particles in the deeps may limit ratio variability at the seafloor. Sediment trap data do not exist for the regional determination of rain ratios in key highly productive areas like the eastern equatorial Pacific (EEP). To overcome this, we turn to surface sediment composition and accumulation rates as a representation of modern ratio variation. We present 230Thorium ( 230Th)-normalized carbonate, opal, organic carbon and detrital matter accumulation rates from core top samples in the EEP. We demonstrate a novel approach for estimating modern rain ratios from sedimentary proxies by (1) calculating vertical calcite flux from 230Th-normalized carbonate accumulation rates (CARs) with correction for preservation and (2) calculating organic carbon fluxes with multiple algorithms that depend in varying degrees on ballasting. We find that organic carbon flux estimates from algorithms with and without a ballasting function produce results different from one another. Sediment accumulation rates for opal reflect the likely pattern of diatom production. By contrast, the organic carbon accumulation rate does not correlate well with surface ocean productivity or any of our algorithm-based organic carbon flux estimates. Instead, it correlates with the detrital component of the sediments suggesting an allochthonous input to sedimentary organic carbon accumulation in the EEP, which reduces its value as a productivity

  17. Petrology and geochemistry of the San Félix-San Ambrosio islands, Eastern Pacific

    Science.gov (United States)

    Cooper Percker, Oliver; Lara, Luis E.

    2015-04-01

    The San Félix-San Ambrosio (SF-SA) islands, Eastern Pacific, are fragments of two volcanic sequences 20 km apart. Both represent the top of an eroded large shield-volcano which rises over the Nazca Plate. Here, new geochemical and 40Ar/39Ar geochronological data are presented in order to understand magmatic evolution and source features. Two units are recognized on the SF island: (1) the Cerro Amarillo unit (CAU) (190±30 ka) formed by a hyaloclastic-tuff cone and basanitic lavas (Ba/Yb=519; Ba/Zr=2.19; La/Yb=49.88; Nb/Ta=17.96; Nb/Y=3.78; Nb/Zr=0.25) with absent or scarce modal content of plagioclase (20%). The hyaloclastic-tuff cone of the CAU contains aphanitic-trachytic lithic fragments of Na-augite and kaersutite, which correspond to the final product of fractional crystallization of olivine+clinopyroxene+Fe-Ti oxides+apatite±plagioclase from alkaline primitive liquids similar to SF-SA lavas. The geochemical data suggest that the islands represent different evolutive stages of a same volcanic intraplate complex. The alkaline to transitional SA lavas (Ba/Yb=249; Ba/Zr=1.60; La/Yb=24.62; Nb/Ta=16.55; Nb/Y=2.22; Nb/Zr=0.19) would represent the shield stage (ca 2.9 Ma), while the basanitic SF lavas the post-erosional stage (ca 0.2 Ma). Considering the Sr-Nd-Pb isotopic data of the SF-SA lavas, previous works have ruled out a genetic relationship between SF-SA islands and the nearby Nazca Ridge. An heterogeneous mantle plume with mantelic metasomatized recycled lithologies is hypothesized as a possible magmatic source capable of explaining the petrologic differences between the SF-SA islands and between the CAU and PU, in SF island. This research is supported by FONDECYT Project 1141303.

  18. Ocean Colour Radiometry across the Southern Atlantic and South-Eastern Pacific

    Science.gov (United States)

    Rudorff, N. D.; Kampel, M.; Frouin, R. J.

    2011-12-01

    An oceanographic cruise across the Southern Atlantic and South-eastern Pacific was undertaken from February 20th to March 14th, 2011, on board the R/V Melville (MV1102). The research vessel crossed highly dynamic regions with important roles on regional and global biogeochemical cycles, such as: the Benguela Upwelling System, the Subtropical Convergence Zone, the Patagonian Shelf, the Magellan Strait, and the Chilean Eastern Boundary Upwelling Zone. The Southern Ocean has been focus of many ocean colour studies due to the high spatio-temporal variability of bio-optical constituents and its biogeochemical importance. Nevertheless, the high latitudes and rough seas of the Southern Ocean are a great challenge for the estimation of these properties from in situ and satellite sensors. The present work shows the first results of the MV1102 cruise with the aim to access the magnitude and possible sources of errors for the estimation of in situ above water remote sensing reflectance (Rrs). Simultaneous measurements were taken at 18 stations with two hyperspectral radiometers: the Fieldspec HandHeld ASD Inc. (350-1100nm) for above water measurements, and the HyperOCR II Satlantic Inc. (380-800 nm) for in-water profiles. Above water measurements were performed with a sensor viewing geometry of 45o zenith and 137o azimuth solar angles, and the downwelling solar irradiance (ED) was estimated using a white Spectralon plaque. The Rrs was estimated with an average of 10 casts per station, and different sky reflectance factors were used to adjust to environmental conditions. Two methods were used to retrieve the Rrs: M01, without the residual sky correction (RSC); and M02, with the RSC, subtracting the Rrs at 870 nm, as a white spectral offset. The M02 was applied for all stations except in the Magellan Strait (coastal waters). For the profiler, the above water Rrs was estimated using two methods: MP01, with the ED measured from the profiler; and MP02, with ED measured from the

  19. New records of sabellids and serpulids (Polychaeta: Sabellidae, Serpulidae) from the Tropical Eastern Pacific

    DEFF Research Database (Denmark)

    Rolando Bastida-Zavala, J.; Rodriguez Buelna, Alondra Sofia; Angel De Leon-Gonzalez, Jesus

    2016-01-01

    in the large expanse of the central and southern Mexican Pacific. Thus, sabellids and serpulids were collected from several shallow water habitats along the coast of Mexican Pacific, such as coastal lagoons, coral reefs, rocky shores and from man-made structures as marinas, piers and ships of several harbors...

  20. Contrasting seasonal drivers of virus abundance and production in the North Pacific Ocean.

    Science.gov (United States)

    Gainer, P Jackson; Pound, Helena L; Larkin, Alyse A; LeCleir, Gary R; DeBruyn, Jennifer M; Zinser, Erik R; Johnson, Zackary I; Wilhelm, Steven W

    2017-01-01

    The North Pacific Ocean (between approximately 0°N and 50°N) contains the largest continuous ecosystem on Earth. This region plays a vital role in the cycling of globally important nutrients as well as carbon. Although the microbial communities in this region have been assessed, the dynamics of viruses (abundances and production rates) remains understudied. To address this gap, scientific cruises during the winter and summer seasons (2013) covered the North Pacific basin to determine factors that may drive virus abundances and production rates. Along with information on virus particle abundance and production, we collected a spectrum of oceanographic metrics as well as information on microbial diversity. The data suggest that both biotic and abiotic factors affect the distribution of virus particles. Factors influencing virus dynamics did not vary greatly between seasons, although the abundance of viruses was almost an order of magnitude greater in the summer. When considered in the context of microbial community structure, our observations suggest that members of the bacterial phyla Proteobacteria, Planctomycetes, and Bacteroidetes were correlated to both virus abundances and virus production rates: these phyla have been shown to be enriched in particle associated communities. The findings suggest that environmental factors influence virus community functions (e.g., virion particle degradation) and that particle-associated communities may be important drivers of virus activity.

  1. Export of Pacific carbon through the Arctic Archipelago to the North Atlantic

    Science.gov (United States)

    Shadwick, E. H.; Thomas, H.; Gratton, Y.; Leong, D.; Moore, S. A.; Papakyriakou, T.; Prowe, A. E. F.

    2011-05-01

    During an east-to-west transect through the Canadian Arctic Archipelago, dissolved inorganic carbon (DIC) and total alkalinity (TA) were measured. The watermass composition throughout the Archipelago is determined using TA and the seawater oxygen isotope fractionation ( δ18O) data, and the carbon characteristics of these waters are examined. The influence of the Mackenzie River is primarily limited to the upper water column in the western Archipelago while the fraction of sea-ice melt water in the surface waters increases eastward with maximum values at the outflows of Jones and Lancaster Sounds. The depth of Pacific-origin upper halocline waters increases eastward through the Archipelago. In the western Archipelago, non-conservative variations in deep water DIC are used to compute a subsurface carbon surplus, which appears to be fueled by organic matter produced in the surface layer and by benthic respiration. The eastward transport of carbon from the Pacific, via the Arctic Archipelago, to the North Atlantic is estimated, and the impact of increased export of sea-ice melt water to the North Atlantic is discussed.

  2. North Pacific Mesoscale Coupled Air-Ocean Simulations Compared with Observations

    Energy Technology Data Exchange (ETDEWEB)

    Koracin, Darko; Cerovecki, Ivana; Vellore, Ramesh; Mejia, John; Hatchett, Benjamin; McCord, Travis; McLean, Julie; Dorman, Clive

    2013-04-11

    Executive summary The main objective of the study was to investigate atmospheric and ocean interaction processes in the western Pacific and, in particular, effects of significant ocean heat loss in the Kuroshio and Kuroshio Extension regions on the lower and upper atmosphere. It is yet to be determined how significant are these processes are on climate scales. The understanding of these processes led us also to development of the methodology of coupling the Weather and Research Forecasting model with the Parallel Ocean Program model for western Pacific regional weather and climate simulations. We tested NCAR-developed research software Coupler 7 for coupling of the WRF and POP models and assessed its usability for regional-scale applications. We completed test simulations using the Coupler 7 framework, but implemented a standard WRF model code with options for both one- and two-way mode coupling. This type of coupling will allow us to seamlessly incorporate new WRF updates and versions in the future. We also performed a long-term WRF simulation (15 years) covering the entire North Pacific as well as high-resolution simulations of a case study which included extreme ocean heat losses in the Kuroshio and Kuroshio Extension regions. Since the extreme ocean heat loss occurs during winter cold air outbreaks (CAO), we simulated and analyzed a case study of a severe CAO event in January 2000 in detail. We found that the ocean heat loss induced by CAOs is amplified by additional advection from mesocyclones forming on the southern part of the Japan Sea. Large scale synoptic patterns with anomalously strong anticyclone over Siberia and Mongolia, deep Aleutian Low, and the Pacific subtropical ridge are a crucial setup for the CAO. It was found that the onset of the CAO