The variability and heat budget of the upper ocean under the Chile-Peru stratus

Author Posting. © Sears Foundation for Marine Research, 2007. This article is posted here by permission of Sears Foundation for Marine Research for personal use, not for redistribution. The definitive version was published in Journal of Marine Research 65 (2007): 607-637, doi:10.1357/002224007783649510.The persistent stratus clouds found west of Chile and Peru are important for the coupling of the ocean and atmosphere in the eastern Pacific and thus in the climate of the region. The relatively cool sea-surface temperatures found west of Peru and northern Chile are believed to play a role in maintaining the stratus clouds over the region. In October 2000 a buoy was deployed at 20S, 85W, a site near the center of the stratus region, in order to examine the variability of sea-surface temperature and the temporal evolution of the vertical structure of the upper ocean. The buoy was wellinstrumented and obtained accurate time series of the surface forcing as well as time series in the upper ocean of temperature, salinity, and velocity. The variability and the extent to which local forcing explains the temporal evolution of upper ocean structure and heat content was examined. The sources of heating (primarily surface fluxes with weaker contributions from Ekman convergence and transport) are found to be balanced by cooling from the gyre-scale circulation, an eddy flux divergence and vertical diffusion. The deduced eddy flux divergence term is bounded away from zero and represents an order one source of cooling (and freshening). We postulate that the eddy flux divergence represents the effect of the cold coherent eddies formed near the coast, which propagate westward and slowly decay. Direct advection of coastal upwelled water by Ekman transport is negligible. Thus the upwelled water does influence the offshore structure, but through the fluctuating mesoscale flow not the mean transport.Support for the buoy deployments and the analysis from NOAA is greatly appreciated (Grants NA17RJ1223 and NA17RJ1224)

An 18S ribosomal DNA barcode for the study of Isomermis lairdi, a parasite of the blackfly Simulium damnosum s.l.

The mermithid parasite, Isomermis lairdi Mondet, Poinar & Bernadou (Nematoda: Mermithidae), is known to have a major impact on populations of Simulium damnosum s.l. Theobald (Diptera: Simuliidae) and on their efficiency as vectors of Onchocerca volvulus (Leuckart) (Nematoda: Filarioidea). However, the value of I. lairdi and other mermithid parasites as potential means of integrated vector control has not been fully realized. This is partly because traditional taxonomic approaches have been insufficient for describing and analysing important aspects of their biology and host range. In total, rDNA barcode sequences have been obtained from over 70 I. lairdi mermithids found parasitizing S. damnosum s.l. larvae in three different rivers. No two sequences were found to vary by more than 0.5%, and cytospecies identification of mermithid hosts revealed that I. lairdi with identical rDNA barcodes can parasitize multiple cytoforms of the S. damnosum complex, including S. squamosum (Enderlein). Phylogenetic analysis using a partial sequence from the 18S ribosomal DNA barcode, grouped I. lairdi in a monophyletic group with Gastromermis viridis Welch (Nematoda: Mermithidae) and Isomermis wisconsinensis Welch (Nematoda: Mermithidae)

The Genus Palaeagapetus Ulmer (Trichoptera, Hydroptilidae, Ptilocolepinae) in North America

The genus Palaeagapetus Ulmer (Trichoptera, Hydroptilidae, Ptilocolepinae) is revised in North America. Descriptions of the western species, P. nearcticus Banks 1938, are provided with the first descriptions of the female, pupa, larva, egg and case and with notes on food, habitat and annual life cycle. The male and female of the eastern species, P. celsus Ross 1936, are described or redescribed with some ecological notes. Distributions of the two species are summarized

Eddies and an extreme water mass anomaly observed in the eastern south Pacific at the Stratus mooring

In the tropical eastern South Pacific the Stratus Ocean Reference Station (ORS) (∼20°S, 85.5°W) is located in the transition zone between the oxygen minimum zone (OMZ) and the well-oxygenated subtropical gyre. In February/March 2012, extremely anomalous water mass properties were observed in the thermocline at the Stratus ORS. The available eddy oxygen anomaly was −10.5 × 1016 µmol. This anomalous water was contained in an anticyclonic mode-water eddy crossing the mooring site. This eddy was absorbed at that time by an anticyclonic feature located south of the Stratus mooring. This was the largest water property anomaly observed at the mooring during the 13.5 month deployment period. The sea surface height anomaly (SSHA) of the strong mode-water eddy in February/March 2012 was weak, and while the lowest and highest SSHA were related to weak eddies, SSHA is found not to be sufficient to specify the eddy strength for subsurface-intensified eddies. Still, the anticyclonic eddy, and its related water mass characteristics, could be tracked backward in time in SSHA satellite data to a formation region in April 2011 off the Chilean coast. The resulting mean westward propagation velocity was 5.5 cm s−1. This extremely long-lived eddy carried the water characteristics from the near-coastal Chilean water to the open ocean. The water mass stayed isolated during the 11 month travel time due to high rotational speed of about 20 cm s−1 leading to almost zero oxygen in the subsurface layer of the anticyclonic mode-water eddy with indications of high primary production just below the mixed layer

Stratus Ocean Reference Station (20˚S, 85˚W), mooring recovery and deployment cruise, R/V Ron Brown cruise 04-11, December 5 - December 24, 2004

The Ocean Reference Station at 20° S, 85° W under the stratus clouds west of northern Chile and Peru is being maintained to provide ongoing, climate-quality records of surface meteorology, of air-sea fluxes of heat, freshwater, and momentum, and of upper ocean temperature, salinity, and velocity variability. The Stratus Ocean Reference Station (ORS Stratus) is supported by the National Oceanic and Atmospheric Administration’s (NOAA) Climate Observation Program. It is recovered and redeployed annually, with cruises that have come between October and December. During the December 2004 cruise of NOAA's R/V Ronald H. Brown to the ORS Stratus site, the primary activities where the recovery of the WHOI surface mooring that had been deployed in November 2003, the deployment of a new WHOI surface mooring at that site, the in-situ calibration of the buoy meteorological sensors by comparison with instrumentation put on board by staff of the NOAA Environmental Technology Laboratory (ETL), and observations of the stratus clouds and lower atmosphere by NOAA ETL and Jason Tomlinson from Texas A&M. The ORS Stratus buoys are equipped with two Improved Meteorological systems, which provide surface wind speed and direction, air temperature, relative humidity, barometric pressure, incoming shortwave radiation, incoming longwave radiation, precipitation rate, and sea surface temperature. The IMET data are made available in near real time using satellite telemetry. The mooring line carries instruments to measure ocean salinity, temperature, and currents. The ETL instrumentation used during the 2004 cruise included cloud radar, radiosonde balloons, and sensors for mean and turbulent surface meteorology. The atmospheric observations also benefited from the C-Band radar mounted on the R/V Ronald H. Brown. In addition to this work, buoy work was done in support of the Chilean Navy Hydrographic and Oceanographic Service (SHOA). A tsunami warning mooring was reinstalled at 75°W, 20°S for SHOA, after the previous buoy installed last year failed. SHOA personnel were onboard to direct the deployment and to gain experience. Four students from the University of Concepcion collected hydrographic data and water samples. One other Chilean student from the University of Chile was involved in the atmospheric sampling program, with a particular focus on the near coast jet. Finally, the cruise hosted a teacher participating in NOAA's Teacher at Sea Program, Mary Esther Cook, who used her experience to develop lessons for her class back in Arkansas.Funding was provided by the National Oceanic and Atmospheric Administration under Contract Number NA17RJ1225

Morphometric comparison of Simulium perflavum larvae (Diptera: Simuliidae) in relation to season and gender in Central Amazônia, Brazil

Number of larval instars, age structure and environmental effects on these parameters represent basic information in the study of insect population biology. When species have economic importance, this information is essential in order to choose the best period to apply different control methods and to determine the stages of the life cycle of the insect that are most susceptible to each treatment. The family Simuliidae has many species of medical/veterinary importance in the world, and some studies in the temperate region have suggested that the number of larval instars and the larval size can vary according to the season, gender and some environmental factors, such as temperature and diet. This study, with the zoophilic species Simulium perflavum Roubaud, is the first in the Neotropics observing some of these factors and will serve as a template for other species of medical importance in the region. S. perflavum larvae were collected in five streams in Central Amazônia (Manaus and Presidente Figueiredo counties, State of Amazonas), in Sept./Oct. 1996 (dry season) and Feb./Mar. 1997 (rainy season). These larvae were measured (lateral length of head capsule and width of cephalic apodema) to determine the number of larval instars (n=3985), to compare the larval size between seasons and genders (last and penultimate larval instars, n=200). Seven larval instars were determined for this species using frequency distributions, t-tests and Crosby´s growth rule. Significant differences were not detected (t-test, p>0.05) in larval size between seasons and genders. Our results differ from some found in temperate regions suggesting that in the Neotropical region the larval size in different seasons and different genders remains constant, although some environmental parameters, such as diet, change depending on the season

Accuracy of the IMET sensor package in the subtropics

Author Posting. © American Meteorological Society, 2009. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Atmospheric and Oceanic Technology 26 (2009): 1867-1890, doi:10.1175/2009JTECHO667.1.The accuracies of the meteorological sensors (air temperature, relative humidity, barometric pressure, near-surface temperature, longwave and shortwave radiation, and wind speed and direction) that compose the Improved Meteorological (IMET) system used on buoys at long-term ocean time series sites known as ocean reference stations (ORS) are analyzed to determine their absolute error characteristics. The predicted errors are compared to in situ measurement discrepancies and other observations (direct flux shipboard sensors) to confirm the predictions. The meteorological errors are then propagated through bulk flux formulas and the Coupled Ocean–Atmosphere Response Experiment (COARE) algorithm to give predicted errors for the heat flux components, the freshwater flux, and the momentum flux. Absolute errors are presented for three frequency bands [instantaneous (1-min sampling), diurnal, and annual]. The absolute uncertainty in the annually averaged net heat flux is found to be 8 W m−2 for conditions similar to the current ORS deployments in the subtropics.Support for the buoy deployments and the analysis from the NOAA Climate Observation Program is greatly appreciated (Grants NA17RJ1223 and NA17RJ1224)

Sea Surface Salinity and Temperature Budgets in the North Atlantic Subtropical Gyre during SPURS Experiment: August 2012-August 2013

Variability at large to meso-scale in sea surface salinity (SSS) and sea surface temperature (SST) is investigated in the subtropical North Atlantic Ocean during the Subtropical Atlantic Surface Salinity Experiment Strasse/SPURS in August 2012 - August 2013. The products of the Soil Moisture and Ocean Salinity (SMOS) mission corrected from large scale systematic errors are tested and used to retrieve meso-scale salinity features, while OSTIA products, resolving meso-scale temperature features are used for SST. The comparison of corrected SMOS SSS data with drifter's in situ measurements from SPURS experiment shows a reasonable agreement, especially during winter time with RMS differences on the order of 0.15 pss (for 10 days, 75 km resolution SMOS product). The analysis of SSS (SST) variability reveals that the meso-scale eddies contribute to a substantial freshening (cooling) in the central high salinity region of the subtropical gyre, albeit smaller than Ekman and atmospheric freshwater (heat) seasonal flux, which are the leading terms in SSS (SST) budget. An error is estimated along with SSS and SST budgets; as well as sensitivity to the different products in use and residuals are discussed. The residuals in the SSS budget are large and can arise from errors in the advection fields and freshwater flux, from neglected small scale or unresolved local processes (salt fingering, vertical mixing and small scale subduction, etc.). However, their magnitude is similar to what is often parameterized as eddy horizontal diffusion to close large scale budgets

A surface mooring for air–sea interaction research in the Gulf Stream. Part II : analysis of the observations and their accuracies

Author Posting. © American Meteorological Society, 2013. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Atmospheric and Oceanic Technology 39 (2013): 450–469, doi:10.1175/JTECH-D-12-00078.1.A surface mooring was deployed in the Gulf Stream for 15 months to investigate the role of air–sea interaction in mode water formation and other processes. The accuracies of the near-surface meteorological and oceanographic measurements are investigated. In addition, the impacts of these measurement errors on the estimation and study of the air–sea fluxes in the Gulf Stream are discussed. Pre- and postdeployment calibrations together with in situ comparison between shipboard and moored sensors supported the identification of biases due to sensor drifts, sensor electronics, and calibration errors. A postdeployment field study was used to further investigate the performance of the wind sensors. The use of redundant sensor sets not only supported the filling of data gaps but also allowed an examination of the contribution of random errors. Air–sea fluxes were also analyzed and computed from both Coupled Ocean–Atmosphere Response Experiment (COARE) bulk parameterization and using direct covariance measurements. The basic conclusion is that the surface buoy deployed in the Gulf Stream to support air–sea interaction research was successful, providing an improved 15-month record of surface meteorology, upper-ocean variability, and air–sea fluxes with known accuracies. At the same time, the coincident deployment of mean meteorological and turbulent flux sensors proved to be a successful strategy to certify the validity of the bulk formula fluxes over the midrange of wind speeds and to support further work to address the present shortcomings of the bulk formula methods at the low and high wind speeds.The National Science Foundation (Grant OCE04-24536) funded this work, as part of the CLIVAR Mode Water Dynamics Experiment (CLIMODE). The Vetlesen Foundation is also acknowledged for the early support of S. Bigorre.2013-09-0

Nematode endoparasites do not codiversify with their stick insect hosts.

Host-parasite coevolution stems from reciprocal selection on host resistance and parasite infectivity, and can generate some of the strongest selective pressures known in nature. It is widely seen as a major driver of diversification, the most extreme case being parallel speciation in hosts and their associated parasites. Here, we report on endoparasitic nematodes, most likely members of the mermithid family, infecting different Timema stick insect species throughout California. The nematodes develop in the hemolymph of their insect host and kill it upon emergence, completely impeding host reproduction. Given the direct exposure of the endoparasites to the host's immune system in the hemolymph, and the consequences of infection on host fitness, we predicted that divergence among hosts may drive parallel divergence in the endoparasites. Our phylogenetic analyses suggested the presence of two differentiated endoparasite lineages. However, independently of whether the two lineages were considered separately or jointly, we found a complete lack of codivergence between the endoparasitic nematodes and their hosts in spite of extensive genetic variation among hosts and among parasites. Instead, there was strong isolation by distance among the endoparasitic nematodes, indicating that geography plays a more important role than host-related adaptations in driving parasite diversification in this system. The accumulating evidence for lack of codiversification between parasites and their hosts at macroevolutionary scales contrasts with the overwhelming evidence for coevolution within populations, and calls for studies linking micro- versus macroevolutionary dynamics in host-parasite interactions