Wind surge and saltwater intrusion in Atchafalaya Bay during onshore winds prior to cold front passage

Cold front passages are largely responsible for accretion along the Chenier Plain, west of the Atchafalaya River as well as many processes impacting the overall health and functioning of the coastal bays and wetlands. The associated water setup and set down during a frontal passage, when wind quickly switches from generally south to north, has significant implications for Louisiana’s bays, coastlines, larval transport, fishery, and oyster resources. The Atchafalaya River discharges up to 30% of the freshwater from the Mississippi River which results in an almost entirely fresh Atchafalaya Bay in spring. A one-month deployment of two tripods equipped with multiple sensors was made in the central Atchafalaya Bay near the Wax Lake Delta for the study of the impact of cold front passages on saltwater flux into the bay between March 20 and April 19, 2006. It was found that two episodes of saltwater intrusion occurred during the 1-month deployment. These events had rapid and transient increases of salinity of approximately 2 PSU. These saltwater intrusion events occurred after a high water slack and lasted for 0.5 to 2 h, respectively. High tide appears to be a necessary condition for the saltwater intrusion. This “high tide”, however, can be a combination of the astronomical tides and wind-induced surge. Strong southerly wind prior to a cold front passage can be an important additional forcing to initiate and/or strengthen saltwater intrusion. It is estimated that roughly 50% of the observed setup is due to local wind stress, 25% due to wave setup, and 25% due to low atmospheric pressure during a cold front passage. The Coriolis-induced setup is found to be negligible in the current study.     

RAPTOR MIGRATION ACROSS THE STRAITS OF GIBRALTAR

The visible migration of birds of prey at Gibraltar is analysed from records kept throughout the spring passages of 1967–70 and the autumn passages of 1967–69. In early spring most visible passage is noted in the afternoons, whereas radar observations by Houghton (1970) indicate passage in the mornings. Later in the year an additional burst of visible passage sometimes occurs in the early morning, but it is concluded that most morning movements take place above visible range. Visible migration is recorded on most days of westerly wind during the migration seasons at Gibraltar. Passage is rarely seen when the winds are easterly. It is argued that under the latter conditions a strong upcurrent of air (standing wave) is formed over Gibraltar, and that this carries nearly all migrants above visible range.
Observations of visible passage elsewhere in the Straits suggest that, in spring, raptors of all species cross on a broad front from Tangier to Ceuta, except Honey Buzzards, which probably cross chiefly near Ceuta. In autumn, all species from northern Europe cross chiefly between Tarifa and to the east of Gibraltar, while birds from western Iberia probably cross mainly near Tarifa.
The periods of passage of the common migrant species are summarised.
On the basis of visual observations and published radar results, it is argued that raptors can compensate for lateral drift by the wind and so fly on chosen courses; but that in very strong cross-winds, e.g. the easterly Levanters, they may have to let themselves be drifted off-course.     

Changes in growth characteristics of mouse ascites tumor AISM during the process of passage in vivo

The growth characteristic of mouse ascites tumour AISM was observed on two distant passages (35th and 117th) in vivo. The following growth differences were established; the duration of life time of tumour bearing mice is less at the 35th passage (8 days) in comparison to the 117th passage (12 days); the common tumour cell mass at the terminal stage of life of tumour is more than 10 times less at 35th passage (10(8) cells) than at 117th passage (1.2.10(9) cells). The growth rate at 35th passage increases to the 4th day and at 117th passage to the 6th day. It is suggested that the tumour growth rate and the final size of tumor cell mass depend on the cell ploidity and chalone growth control.     

Replicative senescence, telomere shortening and cell proliferation rate in Gaddi goat's skin fibroblast cell line

We assessed aging in continuous donor skin fibroblast cell line GGM5 up to the 25th passage by in vitro replicative senescence, telomere dynamics and chromosomal abnormalities. Cell proliferation rate increased from 0.84+/-0.26 (primary cells) to 1.20+/-0.17 (13-15 passage group) per day and reduced to 0.65+/-0.14 in 22-25 passages. Cell proliferation rate was reduced by 45.7% after 87.62 CPDs. Cell viability reduced from 100% to 97.4% up to the 25th passages. Frequency of beta gal(+) cells increased in successive passages and days in culture. The correlation coefficient between frequency of beta gal(+) cells and growth rate was -0.50 to -0.61. Loss of mean TRF length was 13.8 nucleotides (passage 15) to 95.4 nucleotides per cell division in later passages. All cells showed Robertsonian translocation in 22-25 passaged cells. The SCNT pre-implantation embryos production was highest (22.5%) in donor cells used from 10-15 passages as compared to early (相似文献   

Response of carnivores to existing highway culverts and underpasses: implications for road planning and mitigation

Roads with high traffic volumes are a source of animal mortality, can disrupt normal animal movements and dispersal, and may represent a potentially serious threat to wildlife population stability and viability. Retrofitting existing structures built for other purposes (e.g., drainage culverts or small below-grade access roads) to facilitate wildlife crossing by animals and to reduce mortality may be expensive if modifications to the existing structures themselves were involved. However, the environmental context surrounding these structures may influence the willingness of animals to cross, and management of some of these attributes may enhance the attractiveness of these structures. Culverts and underpasses are two common structures along roads in Portugal. We quantified the response of small and medium-sized carnivores to the presence of both types of existing passages by determining: (1) frequency of use; (2) whether use differed by type of passage, and if so; (3) by examining if associated environmental attributes might explain the differences observed. We surveyed 57 different passages along 252 km of highway with a total sampling effort of 2,330 passage trap-days. The mean passage rate for carnivores combined was 0.7 complete passages per crossing structure per day. Crossings by weasel, polecat, otter, and wildcat were infrequent or absent. Red fox, badger, genet and Egyptian mongoose used the crossing structures regularly and without obvious preference; stone marten preferred underpasses. Regression analyses showed the frequency of use by carnivores varied with structural, landscape, road-related features, and human disturbance with 17 of 26 (65%) attributes being significant. Larger passages with vegetation close to the passage entrances, favorable habitat in the surrounding area, and low disturbance by humans were important key features to regular use by the guild of species studied. Mitigation planning in areas with ecological significance for carnivores will be beneficial. Structural attributes and human disturbances are more difficult or expensive to change, even though related significantly to crossing use. Management of vegetation at passage entrances and restricting human use near passages in carnivore suitable areas may substantially improve crossing attractiveness for the guild of carnivore species.     

A search for associations between weather and the onset of human parturition

Weather data were examined for association with hospital records indicating the time at which pregnant women at term first experienced labor contractions (onsets). There is a considerable advantage, compared with mortality and morbidity, to using this response to infer weather influences. Three tests were used. First, the time series of daily onsets was analyzed to determine if characteristics known to exist in time series of weather data — variability and persistence — were evident in daily onsets. Second, the frequency distributions of nine weather variables were stratified, mostly by terciles, and onset means calculated for each of these divisions. Response means much different from average were then used to specify the nature of weather at such times. Third, the weather data were organized as weather types — pre- and post-cold frontal and general cold frontal — and onsets at these times were compared with those at non-frontal times. The time series characteristics were not found, but the other analysis revealed subsets of days on which onsets were above average, and in some cases the results were statistically significant. One such subset consists of winter days with low pressure, temperature markedly lower than the day before, and high wind speeds. On such days onsets were 34% above average. They were also above average during the 48 hours before and after cold front passage, and especially so in the 12 hours prior to the front. These findings constitute a weak, but statistically significant indication that human parturition is influenced by weather. Follow-up studies are urged.     

Factors affecting culvert use by vertebrates along two stretches of road in southern Portugal

A major target for environmental managers when trying to minimise the road-barrier effect on wildlife is to improve permeability to animal movements. Previous studies have demonstrated that drainage culverts are used by vertebrates, although knowledge of the main influencing factors remains limited. The use of 34 culverts from two roads in southern Portugal, differing in traffic volume, vehicle speeds and configuration, was evaluated by the analysis of terrestrial vertebrate footprint data (408 passage-operative days). Culvert crossings were related to various explanatory variables by means of canonical ordination techniques. We recorded 901 complete crossings, corresponding to an average of 2.2 crossings/culvert/operative day. Thirteen taxa were detected, all in more than one passage. Animal species included reptiles, small mammals, lagomorphs, carnivores and domestic dogs and cats. Our results suggest that fencing might have a funnelling effect, directing larger animals toward culverts. Also, vegetation covering culvert entrances seems to have a positive effect, particularly on genets; longer passages with entrances far from the pavement were, apparently, avoided by smaller animals; a lower number of crossings was detected on passages with detritus pits; the closest passages to urban areas are more often used by domestic species; forest-living species favour passages with low, open land cover nearby; and smaller species, like lagomorphs and small mammals, appear to use more culverts near the pavement, which probably reflects the importance of road verges as refuges for these species. Although not used by all species present in the study area, constructing numerous passages of different sizes without detritus pits and which are distributed along roads might be an important step in mitigating road fragmentation effects on animal populations.     

Reading a Suspenseful Literary Text Activates Brain Areas Related to Social Cognition and Predictive Inference

Stories can elicit powerful emotions. A key emotional response to narrative plots (e.g., novels, movies, etc.) is suspense. Suspense appears to build on basic aspects of human cognition such as processes of expectation, anticipation, and prediction. However, the neural processes underlying emotional experiences of suspense have not been previously investigated. We acquired functional magnetic resonance imaging (fMRI) data while participants read a suspenseful literary text (E.T.A. Hoffmann''s “The Sandman”) subdivided into short text passages. Individual ratings of experienced suspense obtained after each text passage were found to be related to activation in the medial frontal cortex, bilateral frontal regions (along the inferior frontal sulcus), lateral premotor cortex, as well as posterior temporal and temporo-parietal areas. The results indicate that the emotional experience of suspense depends on brain areas associated with social cognition and predictive inference.     

Plasmodium berghei: Development of resistance to clindamycin and minocycline in mice

Strains of Plasmodium berghei resistant to clindamycin or minocycline were selected by a procedure in which groups of infected mice were treated with increasing doses of drug during each of a series of subpassages. Groups of five mice, each infected by intravenous inoculation with 10 million parasitized erythrocytes, were treated orally with different doses of drug for four consecutive days beginning on the day of infection. Subpassages were routinely made by Day 7, using donor mice from the group that had been treated with the highest dose of drug that allowed for some development of parasitemia during the preceding passage. Drug doses were increased in each passage as dictated by the development of parasitemia during the previous treated passage.The rate of development of resistance to clindamycin or minocycline was much slower than to conventional antimalarials such as chloroquine, quinine, or pyrimethamine. P. berghei developed total resistance to the latter compounds in nine to 12 treated passages in mice over a period of 60 to 85 days. In contrast, development of total resistance to clindamycin required 42 treated passages over a period of 300 days. Total resistance to minocycline was not attained during 86 successive minocycline-treated passages in mice over a period of 600 days, but a sixfold increase in resistance to minocycline was observed.The clindamycin-resistant strain was normally sensitive to minocycline, chloroquine, quinine, and pyrimethamine. The strain partially resistant to minocycline was normally sensitive to clindamycin, chloroquine, quinine, and pyrimethamine. Resistance to clindamycin was stable during 51 drug-free passages in mice over a period of 1 year. Resistance to minocycline was unstable. During 16 drug-free passages in mice the strain reverted towards normal sensitivity to minocycline. Strains resistant to clindamycin or minocycline showed no difference in rate of development in mice as compared to the parent strain. Likewise, only minor morphological modifications were seen in Giemsa-stained blood smears between the two resistant strains and the parent strain.These results suggest that other species of malaria may develop resistance to clindamycin or minocycline. Should resistance to one of these compounds appear, however, it should not invalidate the use of the other in the treatment of malaria.     

Electron microscopy of Mycobacterium leprae passed in laboratory animals

The ultrastructure of M. leprae was studied in the process of its intraplantar passage from man to mice (passages 1-8). Changes in the morphology of M. leprae, observed in the course of 3 passages, were established. From the phase of dormant forms (passage 1) the bacteria became adapted to the new host by passage 3, which was confirmed by the absence of differences in the ultrastructure of cells by passages 3-8. The possibilities of the phenotypic variability of M. leprae in the process of in vivo passage should be taken into consideration when they are used for the production of specific biopreparations, experimental modeling and the screening of antileprous preparations.     

Enhanced crude oil biodegradability of <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> ZJU after preservation in crude oil-containing medium

This study investigated the enhanced crude oil biodegradability of Pseudomonas aeruginosa ZJU, a strain isolated from the Shengli oil field (Shandong Province, China), after preservation in a crude oil-containing medium. This strain previously could not emulsify crude oil during preservation, but after switching to a subculture in a glycerol medium for passages, it expressed increased biodegradation of crude oil within the first six passages and this biodegradation sharply decreased after the seventh passage. It is noticed that about 70% of crude oil was degraded by Pseudomonas aeruginosa ZJU in the third passage while this biodegradability was less than 19% in the seventh passage. Similar to the trend on biodegradation of crude oil, rhamnolipid production increased during the first six passages and later sharply decreased. Thus, it seems that biodegradability was proportionally related to the rhamnolipid productivity in each passage in glycerol medium. Interestingly, both rhamnolipid production and crude oil biodegradation were maintained if this strain was continuously preserved in crude oil and could be retrieved if this strain was then re-preserved in crude oil-containing medium for seven days after the significant decline in these two characteristics previously observed in the seventh passage.     

Short-Term Reproducibility of Twenty-Four-Hour Intraocular Pressure Curves in Untreated Patients with Primary Open-Angle Glaucoma and Ocular Hypertension

Purpose

To assess the short-term day-to-day reproducibility of 24-hour intraocular pressure (IOP) curves in various respects in untreated primary open-angle glaucoma (POAG) and ocular hypertension (OHT) patients.

Methods

47 subjects with POAG and 34 subjects with OHT underwent IOP measurements every 2 hours in both eyes for consecutive 48 hours by a non-contact tonometer (NCT). IOP values at each time point were recorded. Mean IOP, peak IOP, time difference of peak IOP between two days and IOP fluctuation were also calculated. Intraclass correlation coefficients (ICCs) and Bland-Altman plots were used to evaluate reproducibility.

Results

ICCs of the entire IOP values for a complete 24-hour curve were 0.577 and 0.561 in POAG and OHT patients, respectively. ICCs of IOP values at different time points ranged from 0.384 (10am) to 0.686 (4am) in POAG patients and from 0.347 (6am) to 0.760 (4am) in OHT patients. ICCs of mean IOP, peak IOP and IOP fluctuation were respectively 0.832, 0.704, 0.367 in POAG patients and 0.867, 0.816 0.633 in OHT patients. Only 37.23% and 35.29% of the peak IOP time points appeared within the time difference of 2 hours in POAG and OHT patients, respectively, while 53.19% and 48.53% appeared within 4 hours in POAG and OHT patients, respectively.

Conclusion

A 24-hour IOP curve in a single day is not highly reproducible in short-term and has limited use for evaluating individual IOP condition. Mean IOP and peak IOP for a 24-hour IOP curve are useful parameters in clinical follow-up, while IOP value at a certain time point, IOP fluctuation and peak IOP time point should be interpreted with caution.     

应用不同代次兔肾细胞培养风疹病毒松叶株的研究

目的为提高兔肾细胞产量用于增加风疹病毒生产。方法 SPF级家兔肾细胞经传代培养10代,对不同代次兔肾细胞进行遗传稳定性、外源因子及兔脑原虫检测后接种风疹病毒松叶株(Matsuba strain)的试验。结果兔肾细胞产量得到提高,由1对兔肾平均生产1瓶细胞增加为8瓶,细胞核型检查传至第10代的细胞染色体数目与初代细胞一致,细胞培养物均一性提高。第0～第3代细胞病毒培养物滴度间无显著性差异,χ2检验返回相关性的P值均大于0.95。结论第1～第3代细胞培养风疹病毒与第0代相比,可获得相同滴度的病毒培养物,p3代兔肾细胞应用于疫苗生产可显著提高细胞及病毒产量。     

Behavioral Lateralization and Optimal Route Choice in Flying Budgerigars

Birds flying through a cluttered environment require the ability to choose routes that will take them through the environment safely and quickly. We have investigated some of the strategies by which they achieve this. We trained budgerigars to fly through a tunnel in which they encountered a barrier that offered two passages, positioned side by side, at the halfway point. When one of the passages was substantially wider than the other, the birds tended to fly through the wider passage to continue their transit to the end of the tunnel, regardless of whether this passage was on the right or the left. Evidently, the birds were selecting the safest and quickest route. However, when the two passages were of equal or nearly equal width, some individuals consistently preferred the left-hand passage, while others consistently preferred the passage on the right. Thus, the birds displayed idiosyncratic biases when choosing between alternative routes. Surprisingly - and unlike most of the instances in which behavioral lateralization has previously been discovered - the bias was found to vary from individual to individual, in its direction as well as its magnitude. This is very different from handedness in humans, where the majority of humans are right-handed, giving rise to a so-called ‘population’ bias. Our experimental results and mathematical model of this behavior suggest that individually varying lateralization, working in concert with a tendency to choose the wider aperture, can expedite the passage of a flock of birds through a cluttered environment.     

Automated microscopy as a quantitative method to measure differences in adipogenic differentiation in preparations of human mesenchymal stromal cells

Background aimsMultipotent stromal cells, also called mesenchymal stromal cells (MSCs), are potentially valuable as a cellular therapy because of their differentiation and immunosuppressive properties. As the result of extensive heterogeneity of MSCs, quantitative approaches to measure differentiation capacity between donors and passages on a per-cell basis are needed.MethodsHuman bone marrow-derived MSCs were expanded to passages P3, P5 and P7 from eight different donors and were analyzed for colony-forming unit capacity (CFU), cell size, surface marker expression and forward/side-scatter analysis by flow cytometry. Adipogenic differentiation potential was quantified with the use of automated microscopy. Percentage of adipogenesis was determined by quantifying nuclei and Nile red–positive adipocytes after automated image acquisition.ResultsMSCs varied in expansion capacity and increased in average cell diameter with passage. CFU capacity decreased with passage and varied among cell lines within the same passage. The number of adipogenic precursors varied between cell lines, ranging from 0.5% to 13.6% differentiation at P3. Adipogenic capacity decreased significantly with increasing passage. MSC cell surface marker analysis revealed no changes caused by passaging or donor differences.ConclusionsWe measured adipogenic differentiation on a per-cell basis with high precision and accuracy with the use of automated fluorescence microscopy. We correlated these findings with other quantitative bioassays to better understand the role of donor variability and passaging on CFU, cell size and adipogenic differentiation capacity in vitro. These quantitative approaches provide valuable tools to measure MSC quality and measure functional biological differences between donors and cell passages that are not revealed by conventional MSC cell surface marker analysis.     

Estimating the density and biomass of moray eels (Muraenidae) using a modified visual census method for hole-dwelling reef fauna

Synopsis We developed a modified visual census technique suitable for fairly sedentary, hole-dwelling species and used it to determine the diversity, density, biomass, and habitat use of morays at four sites including fringing, patch, and bank reefs in Barbados, West Indies. The method involved a careful search during two passages over transects by day and by night, noting size and position of morays seen, and using the number of new observations on the second passage to estimate the proportion of morays not seen. First passage counts were generally higher than numbers of morays recorded in previous visual censuses. These estimates were raised when we used the time period (day or night) with the highest average density visible for each species, added different individuals from the two passages, and corrected for individuals not seen. We saw more goldentail morays (Gymnothorax miliaris) during the day but more spotted (G. moringa), viper (Enchelycore nigricans), and chestnut (E. carychroa) morays at night. Counts of chain morays (Echidna catenata) did not differ significantly between night and day. Relative abundance and size of moray species varied among sites and to a lesser extent among habitat types within sites, but spotted morays were generally the most important in numbers and biomass. Mean estimated moray density and biomass were much higher than in most previous visual censuses, but similar to rotenone samples on other reefs and comparable to those of other families of predatory fishes. Our findings confirm that morays are abundant and potentially important predators that should be the focus of more attention in ecological studies of coral reefs.     

Increase in Gs and cyclic AMP generation in HIT cells. Evidence that the 45-kDa alpha-subunit of Gs has greater functional activity than the 52-kDa alpha-subunit

Cyclic AMP accumulation in response to forskolin, cholera toxin, or isoproterenol is dramatically increased in HIT T-15 cells, a clonal cell line of Syrian hamster pancreatic islet beta cells, as a function of passage number. Forskolin and cholera toxin elevate cyclic AMP levels 5- to 10-fold higher in later passages (87-100) than in earlier passages (70-80). A similar phenomenon is observed with isoproterenol (10 microM) which increases cyclic AMP levels 56-fold in older HIT cells (passage 94), whereas only marginally stimulating cyclic AMP production in younger cells (passage 70-82). To determine whether a change in the stimulatory or inhibitory guanine nucleotide regulatory proteins, Gs or Gi, was responsible for these observations, ADP-ribosylation of HIT cell membranes with cholera toxin and pertussis toxin was examined. All passages contained two cholera toxin substrates at 52 and 45 kDa. The amount of 52 kDa did not appear to change with passage number, but the amount of 45 kDa increased in the later passages (89 and 94). The ratio of 45 to 52 kDa cholera toxin substrate, as determined by densitometric analysis, increased from 0.1 in passages 70, 75, and 82 to 0.45 at passage 89. No passage related changes in a 40-kDa pertussis toxin substrate were observed. An increase in the amount of the 45-kDa alpha-subunit of Gs was confirmed on immunoblots using antisera specific for the alpha-subunits of Gs. The amount of functional Gs present in various HIT cell passages was examined by determining the extent to which extracts from HIT cell membranes reconstituted guanine nucleotide-sensitive adenylyl cyclase in S49 cyc- membranes. Extracts derived from passage 94 reconstituted three to four times more adenylyl cyclase activity in cyc- membranes than extracts from passages 70, 75, and 82. These data indicate that an increase in functional Gs in later passages may be the underlying cause for the increased responsiveness to isoproterenol and forskolin in later passages. These data also suggest that functional differences exist between the Gs alpha-subunits, with the smaller 45-kDa subunit being more efficacious in coupling to cyclic AMP synthesis than the larger 52-kDa subunit. This is a departure from the commonly held view that the two subunits have similar efficacies in stimulating adenylyl cyclase.     

Genetic characterization of Sabin types 1 and 3 poliovaccine virus following serial passage in the human intestinal tract.

Poliovirus isolates types 1 and 3 were obtained from five and seven successive passages respectively, in infants who had been fed monovalent OPV in two separate clinical trials conducted in 1960. The purpose of these trials was to answer the question how much the vaccine virus would revert to its original neurovirulent phenotype following multiplication in the intestinal tract. Human passages were performed either by contact exposure or by feeding the excreted virus while the infants were maintained in isolation. Several virus isolates were obtained at each passage level. Infants participating in both studies showed no symptoms of disease. Antigenic studies (McBride, van Wezel) and protein analysis (PAGE) of the isolates, reported earlier from this laboratory, had shown that the isolates remained vaccine-like, although isolates from the later passages revealed some differences. Monkey neurovirulence test results showed that for both types 1 and 3 viruses the loss of attenuation of the vaccine strain upon passage was gradual, although the loss was faster for type 3. Examination of the oligonucleotide maps demonstrated that the oligonucleotide configuration of the isolates remained the same as for the vaccine strain but there was an increase of individual spot differences with increasing passage. The nucleotide sequence analysis of selected regions of the virus genomes revealed that there was no change from a G to A in nucleotide 480 of type 1 isolates; however, nucleotide 476 changed from a U to an A in type 1 passages 3, 4 and 5. Conversely, for type 3 the change of nucleotide 472 from a U to a C changed at the early first passage (4 days following administration of OPV), and remained a C in the six following passages; type 3 nucleotide 2034 did not change in the first passage from a U to a C, but it became a C in all further passages tested. The nucleotide changes mentioned for both virus types remained stable in successive passages. However, there was another nucleotide change for type 3 from a U to a C at position 1973 only for passages 5 and 6 which reverted to a U for passages 7L and 7LL. Study of selected human passage virus strains could further contribute to the identification of the critical nucleotides that are responsible for the attenuation of these two polio types of vaccine viruses.     

The effect of commercial and recreational traffic on the resuspension of sediment in Navigation Pool 9 of the Upper Mississippi River

This study was conducted to determine some effects of commercial and recreational traffic on the resuspension of sediment in Navigation Pool No. 9 of the Upper Mississippi River. Fifty commercial vessel passages were examined at five different main channel locations and at side channels that were adjacent to each of the main channel locations. Sixteen recreational vessel passages were examined at one main channel location and its adjacent side channel and at a channel located in the backwaters. The backwater channel was not directly influenced by navigation in the main channel. Changes in total non-filterable residue (TNFR) and average particle size of suspended silts were used to assess some effects of navigation. Seventy-eight percent of the commercial vessel passages resulted in significant increases of TNFR and/or average particle size in the water column. In the main channel, TNFR increased from 3.4% to 15% above ambient levels; in the side channels, increases ranged from 2.5% to 21.7%. The average diameter of the resuspended silts increased by 0.21 to 2.34 m. In the main channel, 50% of the recreational vessel passages caused increased TNFR and all passages increased average particle size. In the backwater channel, all of the recreational passages caused increases in TNFR and average particle size. Total resuspended sediment transported downstream ranged from an estimated 0.82 to 1015.7 mTons/passage in the main channel for commercial vessels, 0.39 to 0.64 mTons/passage in the main channel for recreational vessels, 0.22 to 28.12 mTons/passage in side channels due to commercial vessels in the main channel, and 0.54 to 2.08 mTons/ passage in the backwater channel for recreational vessels. Bed-sediment composition, location of the vessels in the channel, channel geometry, the number of successive passages, and vessel speed were identified as factors that affected the magnitude of the resuspension.