A Multi-Year Longitudinal Study of Water Quality Parameters in Four Salmon-Bearing and Recreational Streams on Mount Hood,Oregon

Four streams–Clear Fork, Lost Creek, Camp Creek and Still Creek–in northwestern Oregon’s Sandy River Basin were monitored for temperature, dissolved oxygen levels, and fecal bacterial concentrations in a multi-year analysis examining stream health for recreational users and anchor habitat for Pacific Salmon. Temperatures were recorded using micro –T temperature loggers at 15 locations, during 22 July - 5 September 2006, 2 July - 4 September 2007, 20 June - 7 September 2008, 23 June - 9 September 2009, and 2 July –9 September 2010. The Seven-Day Average Maximum water temperature (7-DAM) of 13°C was used as a reference value for the biological limit governing suitable salmonid spawning and egg incubation conditions. The maximum 7-DAM temperatures occurred on different dates and all streams neared or exceeded the 13°C standard at least once each summer. Dissolved oxygen levels were measured at weekly or longer intervals in 2006, 2007, 2008, and 2009. Dissolved oxygen levels fell below the 9.0 ppm standard for Clear Fork on almost half the sampling dates in 2006, 2007, and 2009. Concentrations of the bacterial genus Enterococcus were measured as an indicator of fecal contamination. Samples were collected at 15 sites along the four streams. Weekly samples were collected during a 9 week period from July - September 2007, an 11 week period from June - September 2008, and an 11 week period from June - September 2009. Enterococcus counts exceeded the federal recommended national criterion value of 61 colony forming units (CFU) per 100 mL every year in Camp Creek and occasionally elsewhere, with exceedances trending towards late summer.     

EFFECTS OF SMALL‐SCALE TURBULENCE ON NET GROWTH RATE AND SIZE OF TEN SPECIES OF MARINE DINOFLAGELLATES1

Field observations and results from previous laboratory studies on the effects of turbulence on dinoflagellates have led to a paradigm in phytoplankton ecology that dinoflagellate growth is negatively affected by turbulence. To test the paradigm, 10 species of autotrophic dinoflagellates were exposed to quantified three‐dimensional turbulence generated by vertically oscillating cylindrical rods in 20‐L rectangular culture tanks. Turbulence was quantified in the tanks (as the turbulent energy dissipation rate, ε ) using an acoustic Doppler velocimeter. Dinoflagellates were exposed to two turbulence treatments: high turbulence ( ε ～ 10 ^{? 4} m²·s ^{? 3}), low turbulence ( ε ～ 10 ^{? 8} m²·s ^{? 3}), and an unstirred control. In accord with the paradigm, Ceratium fusus (Ehrenberg) Dujardin had lower net growth rates in high turbulence, whereas Pyrocystis noctiluca Murray ex Haeckel and Ceratium tripos (O. F. Müller) Nitzsch did not increase their numbers in high turbulence. However, Alexandrium tamarense (Lebour) Balech, Pyrocystis fusiformis Wyville‐Thomson ex Murray, Alexandrium catenella (Whedon and Kofoid) Balech, and a Gyrodinium sp. Kofoid and Swezy were apparently unaffected by turbulence and had the same net growth rates across all turbulence treatments. Contradicting the paradigm, Lingulodinium polyedrum (Stein) Dodge (= Gonyaulax polyedra), Gymnodinium catenatum Graham, and Alexandrium fundyense Balech had increased net growth rates in high turbulence treatments. Cross‐sectional area (CSA) varied little across turbulence treatments for 8 of 10 dinoflagellate species tested, CSA in C. fusus increased when net growth rate decreased in high turbulence, and, conversely, CSA decreased in L. polyedrum when net growth rate increased in high turbulence.     

Identification of newly settled Caribbean coral recruits by ITS-targeted single-step nested multiplex PCR

Coral Reefs - As coral cover has declined throughout the Caribbean, interest in determining the potential for reef recovery via natural recruitment processes has increased. Studies investigating...     

Routes of Acquisition of the Gut Microbiota of the Honey Bee Apis mellifera

Studies of newly emerged Apis mellifera worker bees have demonstrated that their guts are colonized by a consistent core microbiota within several days of eclosure. We conducted experiments aimed at illuminating the transmission routes and spatiotemporal colonization dynamics of this microbiota. Experimental groups of newly emerged workers were maintained in cup cages and exposed to different potential transmission sources. Colonization patterns were evaluated using quantitative real-time PCR (qPCR) to assess community sizes and using deep sequencing of 16S rRNA gene amplicons to assess community composition. In addition, we monitored the establishment of the ileum and rectum communities within workers sampled over time from natural hive conditions. The study verified that workers initially lack gut bacteria and gain large characteristic communities in the ileum and rectum within 4 to 6 days within hives. Typical communities, resembling those of workers within hives, were established in the presence of nurse workers or nurse worker fecal material, and atypical communities of noncore or highly skewed compositions were established when workers were exposed only to oral trophallaxis or hive components (comb, honey, bee bread). The core species of Gram-negative bacteria, Snodgrassella alvi, Gilliamella apicola, and Frischella perrara, were dependent on the presence of nurses or hindgut material, whereas some Gram-positive species were more often transferred through exposure to hive components. These results indicate aspects of the colony life cycle and behavior that are key to the propagation of the characteristic honey bee gut microbiota.     

Reduced Risk of Plasmodium vivax Malaria in Papua New Guinean Children with Southeast Asian Ovalocytosis in Two Cohorts and a Case-Control Study

Background

The erythrocyte polymorphism, Southeast Asian ovalocytosis (SAO) (which results from a 27-base pair deletion in the erythrocyte band 3 gene, SLC4A1Δ27) protects against cerebral malaria caused by Plasmodium falciparum; however, it is unknown whether this polymorphism also protects against P. vivax infection and disease.

Methods and Findings

The association between SAO and P. vivax infection was examined through genotyping of 1,975 children enrolled in three independent epidemiological studies conducted in the Madang area of Papua New Guinea. SAO was associated with a statistically significant 46% reduction in the incidence of clinical P. vivax episodes (adjusted incidence rate ratio [IRR] = 0.54, 95% CI 0.40–0.72, p<0.0001) in a cohort of infants aged 3–21 months and a significant 52% reduction in P. vivax (blood-stage) reinfection diagnosed by PCR (95% CI 22–71, p = 0.003) and 55% by light microscopy (95% CI 13–77, p = 0.014), respectively, in a cohort of children aged 5–14 years. SAO was also associated with a reduction in risk of P. vivax parasitaemia in children 3–21 months (1,111/µl versus 636/µl, p = 0.011) and prevalence of P. vivax infections in children 15–21 months (odds ratio [OR] = 0.39, 95% CI 0.23–0.67, p = 0.001). In a case-control study of children aged 0.5–10 years, no child with SAO was found among 27 cases with severe P. vivax or mixed P. falciparum/P. vivax malaria (OR = 0, 95% CI 0–1.56, p = 0.11). SAO was associated with protection against severe P. falciparum malaria (OR = 0.38, 95% CI 0.15–0.87, p = 0.014) but no effect was seen on either the risk of acquiring blood-stage infections or uncomplicated episodes with P. falciparum. Although Duffy antigen receptor expression and function were not affected on SAO erythrocytes compared to non-SAO children, high level (>90% binding inhibition) P. vivax Duffy binding protein–specific binding inhibitory antibodies were observed significantly more often in sera from SAO than non-SAO children (SAO, 22.2%; non-SAO, 6.7%; p = 0.008).

Conclusions

In three independent studies, we observed strong associations between SAO and protection against P. vivax malaria by a mechanism that is independent of the Duffy antigen. P. vivax malaria may have contributed to shaping the unique host genetic adaptations to malaria in Asian and Oceanic populations. Please see later in the article for the Editors'' Summary.     

Heavy Metal Contamination in the Brownfield Soils of Cleveland

The results esults of a survey of heavy metal contamination at Cleveland area brownfields and public spaces are presented. Soils were analyzed using a 24?h, 1N HCl extraction procedure. The study was conducted to seek brownfield soils that manifest properties of “old” sequestered contamination and to develop a better understanding of the nature and extent of heavy metal burdens at brownfield sites in the Greater Cleveland area. The results indicated that Cleveland brownfields commonly yield soil burdens well above remediation triggers for residential soils and often yield values above industrial remediation triggers. It was also discovered that public areas in the vicinity of brownfields commonly have heavy metal contamination significantly above background levels and occasionally above residential remediation triggers. These results indicate that brownfields redevelopment initiatives should proceed with caution. The appropriate remediation goals or restrictions must be imposed to control urban exposure to heavy metal contamination.     

Monitoring the recovery of Juncus roemerianus marsh burns with the normalized difference vegetation index and Landsat Thematic Mapper data

Nine atmospherically corrected Landsat Thematic Mapper images were usedto generate mean normalized difference vegetation indices (NDVI) at 11burn sites throughout a coastal Juncus roemerianus marsh in St. MarksNational Wildlife Refuge, Florida. Time-since-burn, the time lapse from thedate of burn to the date of image collection, was related to variation inmean NDVI over time. Regression analysis showed that NDVI increasedfor about 300 to 400 days immediately after the burn, overshooting thetypical mean NDVI of a nonburned marsh. For about another 500 to 600days NDVI decreased until reaching a nearly constant NDVI of about0.40. During the phase of increasing NDVI the ability to predicttime-since-burn was within about ±60 days. Within the decreasingphase this dropped to about ±88 days.Examination of each burn site revealed some nonburn related influences onNDVI (e.g., seasonality). Normalization of burn NDVI by site-specificnonburn control NDVI eliminated most influences. However, differentialresponses at the site-specific level remained related to either storm impactsor secondary burning. At these sites, collateral data helped clarify theabnormal changes in NDVI. Accounting for these abnormalities,site-specific burn recovery trends could be broadly standardized into fourgeneral phases: Phase 1 – preburn, Phase 2 – initial recovery (increasingNDVI), Phase 3 – late recovery (decreasing NDVI), and Phase 4 – finalcoalescence (unchanging NDVI). Phase 2 tended to last about 300 to 500days, Phase 3 an additional 500 to 600 days, and finally reaching Phase 4,900 to 1,000 days after burn.     

SIMILARITIES IN THE ASEXUAL REPRODUCTION OF THE OCEANIC DINOFLAGELLATES, PYROCYSTIS FUSIFORMIS, PYROCYSTIS LUNULA, AND PYROCYSTIS NOCTILUCA1

Three cultured species of Pyrocystis (Dinoccoccales) reproduced asexually by forming 2 (or 1) aplanospores or zoospores inside the parent cell wall. In all 3 species these small reproductive cells, although they may not resemble the parent cells, swell up rapidly (～ 10 min) to the approximate size and shape of the parent cell. These swollen cells become new vegetative cells. The above asexual process is the only way by which cells numbers increase in our cultures. Pyrocystis lunula was propagated at the lunula stage of the life cycle. The nonmotile crescent-shaped cells produced reproductive cells that were Gymnodinium-shaped and had, in some cases, a trailing flagellum. With P. fusiformis and P. noctiluca, the reproductive cells were not flagellated. With P. fusiformis, these bodies had a pronounced equatorial constriction like a girdle, while in P. noctiluca the “girdle” was an inconspicuous feature if present. With P. noctiluca and P. fusiformis on a 12:12 ld cycle, reproductive cells were formed early in the dark period and they swelled up at the beginning of the light period. Reproduction of P. lunula was not well phased in our experiments, with reproductive cells developing at the end of the light period and the end of the dark period.     

Organisms associated with stimulated epipelagic bioluminescence in the Sargasso Sea and the Gulf Stream

On three cruises, vertical profiles of stimulated bioluminescencewere measured during the late evening in the upper 200 m ofthe Sargasso Sea using a submarine photometer. On one cruise,organisms were collected in a 25 µm porosity net afterpassing through the photometer where the intensity and lightcontent of their bioluminescence were recorded. Correlationsof bioluminescence and organisms suggested that the majorityof the stimulated bioluminescence produced in the Sargasso Seawas from zooplankton: crustaceans (ostracods, copepods, copepodlarvae, euphausid larvae), larvaceans and colonial radiolarians.In addition, the photosynthetic dinoflagellate Pyrocystis noctilucaappeared to produce 5–30% of the measured bioluminescenceat some stations. Other dinoflagellates, although numerous,were dim and thus produced less than a few percent of the stimulatedbioluminescent light. The subsurface peaks in the Gulf Streamand northern Sargasso Sea were due primarily to ostracods andlarvaceans. In the Anegada Passage in October, and in the northernSargasso Sea and the Gulf Stream in August, there were pronouncedsubsurface peaks in bioluminescence associated with the thermocline.In Anegada Passage and the Sargasso Sea just north of PuertoRico in October, and in the Gulf Stream in August, the subsurfacebioluminescence peak was in or slightly above the chlorophyllmaximum. However, at the Sargasso Sea stations in August, itwas 10–40 m above the depth of the chlorophyll maximum.