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Sample records for saltwater crocodiles crocodylus

  1. Cryopreservation of saltwater crocodile (Crocodylus porosus) spermatozoa.

    PubMed

    Johnston, S D; Qualischefski, E; Cooper, J; McLeod, R; Lever, J; Nixon, B; Anderson, A L; Hobbs, R; Gosálvez, J; López-Fernández, C; Keeley, T

    2017-03-30

    The aim of the present study was to develop a protocol for the successful cryopreservation of Saltwater crocodile spermatozoa. Sperm cells were frozen above liquid nitrogen vapour in phosphate-buffered saline (PBS) containing either 0.3M trehalose, 0.3M raffinose or 0.3M sucrose and compared with glycerol (0.3-2.7M). Although the highest levels of mean post-thaw motility were observed following cryopreservation in 0.3M trehalose (7.6%) and 0.3M sucrose (7.3%), plasma membrane integrity (PI) was best following cryopreservation in 2.7M glycerol (52.5%). A pilot study then assessed the cytotoxicity of glycerol and sucrose prior to cryopreservation and revealed no loss of survival when spermatozoa were diluted in 0.68M glycerol or 0.2-0.3M sucrose once cryoprotectants were washed out with PBS or Biggers, Whitten and Whittingham medium containing sperm capacitation agents (BWWCAP). A final study refined the combined use of permeating (0.68 or 1.35M glycerol) and non-permeating (0.2 or 0.3M sucrose) cryoprotectants. Spermatozoa were cryopreserved in liquid nitrogen vapour at rates of approximately -21°Cmin-1 (fast freeze) or -6.0°Cmin-1 (slow freeze). Post-thaw survival was highest with a combination of 0.2M sucrose and 0.68M glycerol and when these cryoprotectants were washed out with BWWCAP, regardless of whether spermatozoa were frozen using a fast (motility 14.2±4.7%; PI 20.7±2.0%) or slow (motility 12.0±2.7%; PI 22±4%) cryopreservation rate.

  2. Spatial resolving power and spectral sensitivity of the saltwater crocodile, Crocodylus porosus, and the freshwater crocodile, Crocodylus johnstoni.

    PubMed

    Nagloo, Nicolas; Collin, Shaun P; Hemmi, Jan M; Hart, Nathan S

    2016-05-01

    Crocodilians are apex amphibious predators that occupy a range of tropical habitats. In this study, we examined whether their semi-aquatic lifestyle and ambush hunting mode are reflected in specific adaptations in the peripheral visual system. Design-based stereology and microspectrophotometry were used to assess spatial resolving power and spectral sensitivity of saltwater (Crocodylus porosus) and freshwater crocodiles (Crocodylus johnstoni). Both species possess a foveal streak that spans the naso-temporal axis and mediates high spatial acuity across the central visual field. The saltwater crocodile and freshwater crocodile have a peak spatial resolving power of 8.8 and 8.0 cycles deg(-1), respectively. Measurement of the outer segment dimensions and spectral absorbance revealed five distinct photoreceptor types consisting of three single cones, one twin cone and a rod. The three single cones (saltwater/freshwater crocodile) are violet (424/426 nm λmax), green (502/510 nm λmax) and red (546/554 nm λmax) sensitive, indicating the potential for trichromatic colour vision. The visual pigments of both members of the twin cones have the same λmax as the red-sensitive single cone and the rod has a λmax at 503/510 nm (saltwater/freshwater). The λmax values of all types of visual pigment occur at longer wavelengths in the freshwater crocodile compared with the saltwater crocodile. Given that there is a greater abundance of long wavelength light in freshwater compared with a saltwater environment, the photoreceptors would be more effective at detecting light in their respective habitats. This suggests that the visual systems of both species are adapted to the photic conditions of their respective ecological niche.

  3. Unexpected lower testosterone in faster growing farmed saltwater crocodile (Crocodylus porosus) hatchlings.

    PubMed

    Finger, John W; Thomson, Peter C; Isberg, Sally R

    2016-01-15

    Agricultural production of the saltwater crocodile (Crocodylus porosus) is an emergent industry in northern Australia with many of the factors affecting production remaining unknown. In this study, we sought to expand upon our previous findings of reference corticosterone and immune function by reporting baseline sex hormone levels [testosterone (TEST) and estradiol (ESTR)] and their association with growth. This was achieved by sampling 253 hatchling crocodiles repeatedly at 3, 6, and 9months of age. Sampling age had a significant effect on both TEST (p<0.001) and ESTR (p<0.001) suggesting climatic/abiotic factors have an influence even in prepubescent crocodiles. Stress, as measured by plasma corticosterone, had no detectable effect on plasma ESTR or TEST levels. Unexpectedly however, TEST was higher in slower-growing crocodiles, which is contrary to what has been reported for the American alligator. ESTR was not associated with growth.

  4. QTL mapping for two commercial traits in farmed saltwater crocodiles (Crocodylus porosus).

    PubMed

    Miles, L G; Isberg, S R; Thomson, P C; Glenn, T C; Lance, S L; Dalzell, P; Moran, C

    2010-04-01

    The recent generation of a genetic linkage map for the saltwater crocodile (Crocodylus porosus) has now made it possible to carry out the systematic searches necessary for the identification of quantitative trait loci (QTL) affecting traits of economic, as well as evolutionary, importance in crocodilians. In this study, we conducted genome-wide scans for two commercially important traits, inventory head length (which is highly correlated with growth rate) and number of scale rows (SR, a skin quality trait), for the existence of QTL in a commercial population of saltwater crocodiles at Darwin Crocodile Farm, Northern Territory, Australia. To account for the uncommonly large difference in sex-specific recombination rates apparent in the saltwater crocodile, a duel mapping strategy was employed. This strategy employed a sib-pair analysis to take advantage of our full-sib pedigree structure, together with a half-sib analysis to account for, and take advantage of, the large difference in sex-specific recombination frequencies. Using these approaches, two putative QTL regions were identified for SR on linkage group 1 (LG1) at 36 cM, and on LG12 at 0 cM. The QTL identified in this investigation represent the first for a crocodilian and indeed for any non-avian member of the Class Reptilia. Mapping of QTL is an important first step towards the identification of genes and causal mutations for commercially important traits and the development of selection tools for implementation in crocodile breeding programmes for the industry.

  5. Molecular identification of three novel herpesviruses found in Australian farmed saltwater crocodiles (Crocodylus porosus) and Australian captive freshwater crocodiles (Crocodylus johnstoni).

    PubMed

    Hyndman, Timothy H; Shilton, Catherine M; Wellehan, James F X; Davis, Steven; Isberg, Sally R; Phalen, David; Melville, Lorna

    2015-12-31

    As part of a larger investigation into three emerging disease syndromes highlighted by conjunctivitis and pharyngitis, systemic lymphoid proliferation and encephalitis, and lymphonodular skin infiltrates in farmed saltwater crocodiles (Crocodylus porosus) and one emerging syndrome of systemic lymphoid proliferation in captive freshwater crocodiles (Crocodylus johnstoni), cytopathic effects (CPE), including syncytial cell formation, were observed in primary crocodile cell lines exposed to clarified tissue homogenates from affected crocodiles. Ten cell cultures with CPE were then screened for herpesviruses using two broadly-reactive herpesvirus PCRs. Amplicons were obtained from 9 of 10 cell cultures and were sequenced. Three novel herpesviruses were discovered and the phylogenetic analysis of these viruses showed there was a 63% Bayesian posterior probability value supporting these viruses clustering with the subfamily Alphaherpesvirinae, and 100% posterior probability of clustering with a clade containing the Alphaherpesvirinae and other unassigned reptile herpesviruses. It is proposed that they are named Crocodyline herpesvirus (CrHV) 1, 2 and 3. CrHV1 and 2 were only isolated from saltwater crocodiles and CrHV3 was only isolated from freshwater crocodiles. A duplex PCR was designed that was able to detect these herpesviruses in formalin-fixed paraffin-embedded tissues, a sample type that neither of the broadly-reactive PCRs was able to detect these herpesviruses in. This work describes the isolation, molecular detection and phylogeny of these novel herpesviruses but the association that they have with the emerging disease syndromes requires further investigation.

  6. Pathology of runting in farmed saltwater crocodiles (Crocodylus porosus) in Australia.

    PubMed

    Shilton, C; Brown, G P; Chambers, L; Benedict, S; Davis, S; Aumann, S; Isberg, S R

    2014-09-01

    Extremely poor growth of some individuals within a birth cohort (runting) is a significant problem in crocodile farming. We conducted a pathological investigation to determine if infectious disease is associated with runting in farmed saltwater crocodiles (Crocodylus porosus) and to look for evidence of other etiologies. In each of 2005 and 2007, 10 normal and 10 runt crocodiles, with an average age of 5.5 months and reared under identical conditions, were sampled. Laboratory testing included postmortem; histological examination of a wide variety of tissues (with quantitation of features that were noted subjectively to be different between groups); hematology; serum biochemistry (total protein, albumin, globulins, total calcium, phosphorus, and iron); bacterial culture of liver and spleen (2005 only); viral culture of liver, thymus, tonsil, and spleen using primary crocodile cell lines (2007 only); and serum corticosterone (2007 only). The only evidence of infectious disease was mild cutaneous poxvirus infection in 45% of normal and 40% of runt crocodiles and rare intestinal coccidia in 5% of normal and 15% of runt crocodiles. Bacterial and viral culture did not reveal significant differences between the 2 groups. However, runt crocodiles exhibited significant (P < .05) increases in adrenocortical cell cytoplasmic vacuolation and serum corticosterone, decreased production of bone (osteoporosis), and reduced lymphoid populations in the spleen, tonsil, and thymus. Runts also exhibited moderate anemia, hypoalbuminemia, and mild hypophosphatemia. Taken together, these findings suggest an association between runting and a chronic stress response (hyperactivity of the hypothalamic-pituitary-adrenal axis).

  7. The complete mitochondrial genome of salt-water crocodile (Crocodylus porosus) and phylogeny of crocodilians.

    PubMed

    Li, Yan; Wu, Xiaobing; Ji, Xuefeng; Yan, Peng; Amato, George

    2007-02-01

    The nucleotide sequence of the complete mitochondrial DNA (mtDNA) molecule of the salt-water crocodile (Crocodylus porosus) was determined in this article. The molecule is 16,917 base pairs (bp) in length, and codes for 22 tRNAs, 13 protein-coding genes, 2 rRNAs, as well as a control region (D-loop), as is characteristic for mitochondrial genomes of other metazoans. The gene order conforms to that of other crocodilians sequenced, but the arrangement of some tRNA genes differs from other vertebrates. It shows that the gene order of crocodilians is remarkably conserved. In this study, the relationships among crocodilians were examined in the phylogenetic analysis based on the control conserved regions of 17 crocodilians. The results suggest that the gharial (Gavialis gangeticus) joins the false gharial (Tomistoma schlegelii) on a common branch, and then constitutes a sister group to traditional Crocodylidae. Thus, the result supports that G. gangeticus belongs to Crocodylidae. The analyses also suggest that the African slender-snouted crocodile (Crocodylus cataphractus) can be treated as an isolated genus, and constitutes a sister group to Crocodylus.

  8. Genetics and infection dynamics of Paratrichosoma sp in farmed saltwater crocodiles (Crocodylus porosus).

    PubMed

    Lott, M J; Hose, G C; Isberg, S R; Power, M L

    2015-02-01

    Paratrichosoma-associated helminthiasis has been identified in saltwater crocodiles under intensive farming conditions. The development of sustainable integrated management practices is dependent on a detailed understanding of Paratrichosoma population genetics and infection dynamics. This study investigated the genetic relationships of Paratrichosoma sp in a population of commercially farmed saltwater crocodiles, Crocodylus porosus, in northern Australia. 18S ribosomal RNA gene sequence data were obtained from Paratrichosoma sp eggs present in the epidermis of infected animals. A high level of genetic diversity was distributed within the Paratrichosoma sp population (241 variable positions in the 1094 bp alignment), indicating an accelerated rate of nucleotide base-pair substitutions in this genus of nematodes. Several possible environmental correlates of the incidence and intensity of helminthiasis, including season, rainfall, and mean monthly temperature, were investigated by visual inspection of crocodile skins. Stepwise logistic regression revealed a significant negative linear relationship (P = 0.011, R (2) = 32.69 %) between mean monthly rainfall and the incidence of monthly Paratrichosoma-associated helminthiasis. Variation in the severity of Paratrichosoma-associated helminthiasis could not be explained by any of the independent environmental variables included within an ordinal regression analysis. The large genetic diversity in these nematodes indicates a high probability of anthelmintic resistant alleles occurring in the population. We discuss how the spread of these alleles may be mitigated by adopting targeted treatment protocols.

  9. Characterization of serum complement activity of saltwater (Crocodylus porosus) and freshwater (Crocodylus johnstoni) crocodiles.

    PubMed

    Merchant, Mark; Britton, Adam

    2006-04-01

    We employed a spectroscopic assay, based on the hemolysis of sheep red blood cells (SRBCs), to assess the innate immune function of saltwater and freshwater crocodiles in vitro. Incubation of serum from freshwater and saltwater crocodiles with SRBCs resulted in concentration-dependent increases in SRBC hemolysis. The hemolytic activity occurred rapidly, with detectable activity within 2 min and maximum activity at 20 min. These activities, in both crocodilian species, were heat sensitive, unaffected by 20 mM methylamine, and completely inhibited by low concentrations of EDTA, suggesting that the alternative serum complement cascade is responsible for the observed effects. The hemolytic activities of the sera were inhibited by other chelators of divalent metal ions, such as phosphate and citrate. The inhibition of SRBC hemolysis by EDTA could be completely restored by the addition of 10 mM Ca2+ or Mg2+, but not Ba2+, Cu2+ or Fe2+, indicating specificity for these metal ions. The serum complement activities of both crocodilians were temperature-dependent, with peak activities occurring at 25-30 degrees C and reduced activities below 25 degrees C and above 35 degrees C.

  10. Standardized reference ideogram for physical mapping in the saltwater crocodile (Crocodylus porosus).

    PubMed

    Dalzell, P; Miles, L G; Isberg, S R; Glenn, T C; King, C; Murtagh, V; Moran, C

    2009-01-01

    Basic cytogenetic data, such as diploid number and general chromosome morphology, are available for many reptilian species. Here we present a detailed cytogenetic examination of the saltwater crocodile (Crocodylus porosus) karyotype, including the creation of the first fully annotated G-band standard ideogram for any crocodilian species. The C. porosus karyotype contains macrochromosomes and has a diploid number of 34. This study presents a detailed description of each chromosome, permitting unambiguous chromosome identification. The fully annotated standardized C. porosus ideogram provides the backbone to a standard nomenclature system which can be used to accurately identify specific band locations. Seven microsatellite containing fosmid clones were fluorescently labeled and used as fluorescent in situ hybridization (FISH) probes for physical localization. Chromosome locations for each of these FISH probes were successfully assigned, demonstrating the utility of the fully annotated ideogram for genome mapping.

  11. Control of the development of the pulmonary surfactant system in the saltwater crocodile, Crocodylus porosus.

    PubMed

    Sullivan, Lucy C; Orgeig, Sandra; Daniels, Christopher B

    2002-11-01

    Pulmonary surfactant is a mixture of lipids and proteins that controls the surface tension of the fluid lining the inner lung. Its composition is conserved among the vertebrates. Here we hypothesize that the in ovo administration of glucocorticoids and thyroid hormones during late incubation will accelerate surfactant development in the saltwater crocodile, Crocodylus porosus. We also hypothesize that the increased maturation of the type II cells in response to hormone pretreatment will result in enhanced responsiveness of the cells to surfactant secretagogues. We sampled embryos at days 60, 68, and 75 of incubation and after hatching. We administered dexamethasone (Dex), 3,5,3'-triiodothyronine (T(3)), or a combination of both hormones (Dex + T(3)), 48 and 24 h before each prehatching time point. Lavage analysis indicated that the maturation of the phospholipids (PL) in the lungs of embryonic crocodiles occurs rapidly. Only T(3) and Dex + T(3) increased total PL in lavage at embryonic day 60, but Dex, T(3), and Dex + T(3) increased PL at day 75. The saturation of the PLs was increased by T(3) and Dex + T(3) at day 68. Swimming exercise did not increase the amount or alter the saturation of the surfactant PLs. Pretreatment of embryos with Dex, T(3), or Dex + T(3) changed the secretion profiles of the isolated type II cells. Dex + T(3) increased the response of the cells to agonists at days 60 and 68. Therefore, glucocorticoids and thyroid hormones regulate surfactant maturation in the crocodile.

  12. Characterization of outer ring iodothyronine deiodinases in tissues of the saltwater crocodile (Crocodylus porosus).

    PubMed

    Shepherdley, Caroline A; Richardson, Samantha J; Evans, Barbara K; Kühn, Eduard R; Darras, Veerle M

    2002-02-15

    The distribution and characterization of outer ring deiodination (ORD) using reverse triiodothyronine (rT3) and thyroxine (T4) as substrates is reported in microsomes of liver, kidney, lung, heart, gut, and brain tissues from juvenile saltwater crocodiles (Crocodylus porosus). In lung and heart only small amounts of rT3 ORD and T4 ORD were detected, while in brain only a small amount of T4 ORD was detected. More detailed characterization studies could be performed on liver, kidney, and gut microsomes. Reverse T3 outer ring deiodination (rT3 ORD) was the predominant activity in liver and kidney microsomes. The properties of crocodile liver and kidney rT3 ORD, such as preference for rT3 as substrate, a dithiothreitol (DTT) requirement of 10 mM, inhibition by propylthiouracil (PTU), and Michaelis-Menten (Km) constant in the micromolar range, correspond to the properties previously reported for a type I deiodinase. The temperature optimum for rT3 ORD was between 30 and 35 degrees. There was also rT3 ORD activity in gut microsomes, along with what appeared to be a type II-like, low-Km deiodinase with a substrate preference for T4. There was also a small amount of T4 ORD activity in liver and kidney microsomes. Liver T4 ORD, like a type II deiodinase, had a preference for T4 as substrate at low substrate concentrations and a DTT requirement of 15 mM and was insensitive to PTU. However, at high substrate concentrations the predominant activity was of the type I deiodinase nature. T4 ORD in liver had an optimal incubation temperature of 30 to 35 degrees. Gut microsomal T4 ORD was also type II-like at low substrate concentrations and type I-like at high substrate concentrations. Gut T4 ORD had an optimal incubation temperature of 25 to 30 degrees and a DTT requirement of 20 mM DTT. Kidney microsomal T4 ORD had the same optimal temperature and DTT requirement as that in gut microsomes; however, there was no competition by low substrate concentrations. These results suggest

  13. Continuous infraclavicular block for forearm amputation after being bitten by a saltwater crocodile (Crocodylus porosus): a case report.

    PubMed

    Chiu, Chin-Hsi; Kuo, Yi-Wei; Hsu, Ho-Te; Chu, Koung-Shing; Shieh, Chia-Fang

    2009-08-01

    Two important issues after a complete right forearm amputation are replantation and ongoing pain management. There are no reports of successful forearm replantation as a consequence of a crocodile bite. Here, we discuss our pain management in a case of complete forearm amputation after a bite from a saltwater crocodile (Crocodylus porosus), which necessitated six further operations to achieve successful replantation. Continuous infraclavicular brachial plexus block was effective for acute pain control in this case. We strongly recommend performing the block with an indwelling catheter under ultrasound guidance for higher accuracy and safety.

  14. Dead or Alive? Factors Affecting the Survival of Victims during Attacks by Saltwater Crocodiles (Crocodylus porosus) in Australia.

    PubMed

    Fukuda, Yusuke; Manolis, Charlie; Saalfeld, Keith; Zuur, Alain

    2015-01-01

    Conflicts between humans and crocodilians are a widespread conservation challenge and the number of crocodile attacks is increasing worldwide. We identified the factors that most effectively decide whether a victim is injured or killed in a crocodile attack by fitting generalized linear models to a 42-year dataset of 87 attacks (27 fatal and 60 non-fatal) by saltwater crocodiles (Crocodylus porosus) in Australia. The models showed that the most influential factors were the difference in body mass between crocodile and victim, and the position of victim in relation to the water at the time of an attack. In-water position (for diving, swimming, and wading) had a higher risk than on-water (boating) or on-land (fishing, and hunting near the water's edge) positions. In the in-water position a 75 kg person would have a relatively high probability of survival (0.81) if attacked by a 300 cm crocodile, but the probability becomes much lower (0.17) with a 400 cm crocodile. If attacked by a crocodile larger than 450 cm, the survival probability would be extremely low (<0.05) regardless of the victim's size. These results indicate that the main cause of death during a crocodile attack is drowning and larger crocodiles can drag a victim more easily into deeper water. A higher risk associated with a larger crocodile in relation to victim's size is highlighted by children's vulnerability to fatal attacks. Since the first recently recorded fatal attack involving a child in 2006, six out of nine fatal attacks (66.7%) involved children, and the average body size of crocodiles responsible for these fatal attacks was considerably smaller (384 cm, 223 kg) than that of crocodiles that killed adults (450 cm, 324 kg) during the same period (2006-2014). These results suggest that culling programs targeting larger crocodiles may not be an effective management option to improve safety for children.

  15. Dead or Alive? Factors Affecting the Survival of Victims during Attacks by Saltwater Crocodiles (Crocodylus porosus) in Australia

    PubMed Central

    Fukuda, Yusuke

    2015-01-01

    Conflicts between humans and crocodilians are a widespread conservation challenge and the number of crocodile attacks is increasing worldwide. We identified the factors that most effectively decide whether a victim is injured or killed in a crocodile attack by fitting generalized linear models to a 42-year dataset of 87 attacks (27 fatal and 60 non-fatal) by saltwater crocodiles (Crocodylus porosus) in Australia. The models showed that the most influential factors were the difference in body mass between crocodile and victim, and the position of victim in relation to the water at the time of an attack. In-water position (for diving, swimming, and wading) had a higher risk than on-water (boating) or on-land (fishing, and hunting near the water's edge) positions. In the in-water position a 75 kg person would have a relatively high probability of survival (0.81) if attacked by a 300 cm crocodile, but the probability becomes much lower (0.17) with a 400 cm crocodile. If attacked by a crocodile larger than 450 cm, the survival probability would be extremely low (<0.05) regardless of the victim’s size. These results indicate that the main cause of death during a crocodile attack is drowning and larger crocodiles can drag a victim more easily into deeper water. A higher risk associated with a larger crocodile in relation to victim’s size is highlighted by children’s vulnerability to fatal attacks. Since the first recently recorded fatal attack involving a child in 2006, six out of nine fatal attacks (66.7%) involved children, and the average body size of crocodiles responsible for these fatal attacks was considerably smaller (384 cm, 223 kg) than that of crocodiles that killed adults (450 cm, 324 kg) during the same period (2006–2014). These results suggest that culling programs targeting larger crocodiles may not be an effective management option to improve safety for children. PMID:25961294

  16. Relationships between blood pressure and heart rate in the saltwater crocodile Crocodylus porosus.

    PubMed

    Altimiras, J; Franklin, C E; Axelsson, M

    1998-08-01

    The cardiac limb of the baroreflex loop was studied in the saltwater crocodile Crocodylus porosus. The classical pharmacological methodology using phenylephrine and sodium nitroprusside was used to trigger blood pressure changes, and the resulting alterations in heart rate were analysed quantitatively using a logistic function. Interindividual differences in resting heart rates and blood pressures were observed, but all seven animals displayed clear baroreflex responses. Atropine and sotalol greatly attenuated the response. A maximal baroreflex gain of 7.2 beats min-1 kPa-1 was found at a mean aortic pressure of 6.1 kPa, indicating the active role of the baroreflex in a wide pressure range encompassing hypotensive and hypertensive states. At the lowest mean aortic pressures (5.0 kPa), the synergistic role of the pulmonary-to-systemic shunt in buffering the blood pressure drop also contributes to blood pressure regulation. Pulse pressure showed a better correlation with heart rate and also a higher gain than mean aortic, systolic or diastolic pressures, and this is taken as an indicator of the existence of a differential control element working simultaneously with a linear proportional element.

  17. Thyroid hormone deiodinases during embryonic development of the saltwater crocodile (Crocodylus porosus).

    PubMed

    Shepherdley, Caroline A; Richardson, Samantha J; Evans, Barbara K; Kühn, Eduard R; Darras, Veerle M

    2002-04-01

    All tissues of the embryonic saltwater crocodile (Crocodylus porosus) gradually increased in weight during development except for lung tissue, which had a peak weight of 1.09 g at day 67, thereafter decreasing in weight. The brain was a relatively large organ. Deiodinase activities in liver, kidney, lung, heart, gut, and brain from day 29 to day 77 of development of the saltwater crocodile were investigated. High-K(m) reverse triiodothyronine (rT(3)) outer ring deiodination (ORD) activity was present in all tissues except the brain. Activity ranged from 559 +/- 51.3 pmol rT(3) deiodinated/mg protein/min in the liver at day 77 to below 10 pmol rT(3) deiodinated/mg protein/min in gut, lung, and heart tissue. rT(3) ORD increased during development in the liver and kidney but decreased in the gut and lung. Activity in the heart was very low (less than 2 pmol rT(3) deiodinated/mg protein/min) and did not change during development. Low-K(m) thyroxine (T(4)) ORD in liver and kidney tissue had peaks of activity around day 49 of incubation (0.52 and 0.09 fmol T(4) deiodinated/mg protein/min, respectively). After day 49, T(4) ORD activity in these tissues decreased. T(4) ORD activity in gut, lung, and heart was very low (less than 0.04 fmol T(4) deiodinated/mg protein/min), with activity in lung increasing slightly during the rest of development. T(4) ORD activity in the brain increased toward day 77 (0.14 +/- 0.03 fmol T(4) deiodinated/mg protein/min), illustrating its importance in local triiodothyronine (T(3)) production during brain development. T(3) inner ring deiodination activity was present only in the embryonic liver and peaked at day 49 (10.1 fmol T(3) deiodinated/mg protein/min), after which activity decreased.

  18. Diagnostic investigation of new disease syndromes in farmed Australian saltwater crocodiles (Crocodylus porosus) reveals associations with herpesviral infection.

    PubMed

    Shilton, Catherine M; Jerrett, Ian V; Davis, Steven; Walsh, Susan; Benedict, Suresh; Isberg, Sally R; Webb, Grahame J W; Manolis, Charlie; Hyndman, Timothy H; Phalen, David; Brown, Gregory P; Melville, Lorna

    2016-05-01

    Since 2006, 3 new disease syndromes have emerged in farmed saltwater crocodiles (Crocodylus porosus) in the Northern Territory of Australia. We describe the syndromes through a retrospective study of laboratory findings from 187 diagnostic cases submitted to Berrimah Veterinary Laboratories between 2005 and 2014. The first syndrome was characterized by conjunctivitis and/or pharyngitis (CP), primarily in hatchlings. Herpesviruses were isolated in primary crocodile cell culture, or were detected by PCR directly from conjunctiva or pharyngeal tissue, in 21 of 39 cases of CP (54%), compared with 9 of 64 crocodiles without the syndrome (14%, p < 0.0001). Chlamydiaceae were detected by PCR in conjunctiva or pharyngeal tissue of 55% of 29 CP cases tested, and of these, 81% also contained herpesvirus. The second syndrome occurred in juveniles and growers exhibiting poor growth, and was characterized histologically by systemic lymphoid proliferation and nonsuppurative encephalitis (SLPE). Herpesviruses were isolated or detected by PCR from at least 1 internal organ in 31 of 33 SLPE cases (94%) compared with 5 of 95 crocodiles without the syndrome (5%, p < 0.0001). The third syndrome, characterized by multifocal lymphohistiocytic infiltration of the dermis (LNS), occurred in 6 harvest-sized crocodiles. Herpesviruses were isolated from at least 1 skin lesion in 4 of these 6 cases. Although our study revealed strong associations between herpesvirus and the CP and SLPE syndromes, the precise nature of the role of herpesvirus, along with the pathogenesis and epidemiology of the syndromes, requires further investigation.

  19. The assessment of sperm DNA fragmentation in the saltwater crocodile (Crocodylus porosus).

    PubMed

    Johnston, S D; López-Fernández, C; Arroyo, F; Fernández, J L; Gosálvez, J

    2015-10-14

    Herein we report a method of assessing DNA fragmentation in the saltwater crocodile using the sperm chromatin dispersion test (SCDt) after including frozen-thawed spermatozoa in a microgel (Halomax; Halotech DNA, Madrid, Spain). Following controlled protein depletion, which included a reducing agent, sperm nuclei with fragmented DNA showed a homogeneous and larger halo of chromatin dispersion with a corresponding reduced nucleoid core compared with sperm with non-fragmented DNA. The presence of DNA damage was confirmed directly by incorporation of modified nucleotides using in situ nick translation (ISNT) and indirectly by studying the correlation of the SCDt with the results of DNA damage visualisation using a two-tailed comet assay (r = 0.90; P = 0.037). Results of the SCDt immediately following thawing and after 5 h incubation at 37°C in order to induce a range of DNA damage revealed individual crocodile differences in both the baseline level of DNA damage and DNA longevity.

  20. Quantitative analysis of production traits in saltwater crocodiles (Crocodylus porosus): II. age at slaughter.

    PubMed

    Isberg, S R; Thomson, P C; Nicholas, F W; Barker, S G; Moran, C

    2005-12-01

    Crocodile morphometric (head, snout-vent and total length) measurements were recorded at three stages during the production chain: hatching, inventory [average age (+/-SE) is 265.1 +/- 0.4 days] and slaughter (average age is 1037.8 +/- 0.4 days). Crocodile skins are used for the manufacture of exclusive leather products, with the most common-sized skin sold having 35-45 cm in belly width. One of the breeding objectives for inclusion into a multitrait genetic improvement programme for saltwater crocodiles is the time taken for a juvenile to reach this size or age at slaughter. A multivariate restricted maximum likelihood analysis provided (co)variance components for estimating the first published genetic parameter estimates for these traits. Heritability (+/-SE) estimates for the traits hatchling snout-vent length, inventory head length and age at slaughter were 0.60 (0.15), 0.59 (0.12) and 0.40 (0.10) respectively. There were strong negative genetic (-0.81 +/- 0.08) and phenotypic (-0.82 +/- 0.02) correlations between age at slaughter and inventory head length.

  1. MHC class I of saltwater crocodiles (Crocodylus porosus): polymorphism and balancing selection.

    PubMed

    Jaratlerdsiri, Weerachai; Isberg, Sally R; Higgins, Damien P; Gongora, Jaime

    2012-11-01

    Saltwater crocodiles are in high demand for the production of luxury fashion items. However, their susceptibility to disease incurs substantial losses and it is hoped to be able to genetically select these animals for disease resistance. So far, this has only been enabled by phenotypic selection. Investigating the major histocompatibility complex (MHC) could provide insight into the ability of an individual to respond to pathogens acting as a selective pressure on the host. Here, we assessed genetic diversity and a role of selection in shaping the diversity of MHC class I exon 3 among 42 saltwater crocodiles from nine river basins in the Northern Territory, Australia. We generated 640 sequences using cloning and sequencing methods and identified 43 MHC variants among them. Phylogenetic analyses clustered these variants into two major clades, which may suggest two gene lineages. We found the number of variants within an individual varying between one and seven, indicating that there are at least four gene loci in this species. Selection detection analyses revealed an elevated ratio of nonsynonymous to synonymous substitutions (mean = 1.152 per codon), suggesting balancing selection. Population differentiation analyses revealed that the MHC did not show structuring among the river basins, and there were some shared variants among them. This may be a result of possible gene flow and/or similar selection pressures among populations. These findings provide background knowledge to identify potential MHC markers, which could be used for selecting genetically variable individuals for future disease associations. All MHC class I exon 3 sequences reported in this paper were submitted to the GenBank database with following accession numbers: HQ008785-HQ008789, HQ008791-HQ008798, HQ008808-HQ008815, HQ008824, HQ008826-HQ008830, HQ008835, HQ008839, HQ008842-HQ008850, and JX023536-JX023540.

  2. Stress in farmed saltwater crocodiles (Crocodylus porosus): no difference between individually- and communally-housed animals.

    PubMed

    Isberg, Sally R; Shilton, Cathy M

    2013-01-01

    Minimising stress in farmed crocodiles is not only important for improving animal welfare, but may also improve skin blemish healing and infection resistance, which influence the quality of the final skin product. Forty near-harvest size saltwater crocodiles (1.6-1.8 m TL) from two Australian farms were sampled to evaluate the effect of different pen types (communal pens n=20; individual pens n=20) on stress as indicated by plasma corticosterone. Blood samples were taken within three minutes of immobilisation and analysed using a commercial enzyme immunoassay kit. There was no relationship with animal size (P=0.16), between farms (P=0.86), pen types (P=0.69), communal pens between farms (P=0.28) or individual pens between farms (P=0.24). Based on corticosterone levels, it appears that individual pens do not cause significantly more stress on harvest-size animals than communal pens. Individual pens meet their design specifications by achieving comparable healing rates of belly skin blemishes as communal pens without compromising animal welfare and minimising the possibility of new blemishes.

  3. Strong purifying selection in endogenous retroviruses in the saltwater crocodile (Crocodylus porosus) in the Northern Territory of Australia

    PubMed Central

    2012-01-01

    Background Endogenous retroviruses (ERVs) are remnants of exogenous retroviruses that have integrated into the nuclear DNA of a germ-line cell. Here we present the results of a survey into the ERV complement of Crocodylus porosus, the saltwater crocodile, representing 45 individuals from 17 sampling locations in the Northern Territory of Australia. These retroelements were compared with published ERVs from other species of Crocodylia (Crocodilians; alligators, caimans, gharials and crocodiles) as well as representatives from other vertebrates. This study represents one of the first in-depth studies of ERVs within a single reptilian species shedding light on the diversity of ERVs and proliferation mechanisms in crocodilians. Results Analyses of the retroviral pro-pol gene region have corroborated the presence of two major clades of ERVs in C. porosus and revealed 18 potentially functional fragments out of the 227 recovered that encode intact pro-pol ORFs. Interestingly, we have identified some patterns of diversification among those ERVs as well as a novel sequence that suggests the presence of an additional retroviral genus in C. porosus. In addition, considerable diversity but low genetic divergence within one of the C. porosus ERV lineages was identified. Conclusions We propose that the ERV complement of C. porosus has come about through a combination of recent infections and replication of ancestral ERVs. Strong purifying selection acting on these clades suggests that this activity is recent or still occurring in the genome of this species. The discovery of potentially functional elements is an interesting development that warrants further investigation. PMID:23217152

  4. Quantitative analysis of production traits in saltwater crocodiles (Crocodylus porosus): IV. number of scale rows.

    PubMed

    Isberg, S R; Thomson, P C; Nicholas, F W; Webb, G J W; Manolis, S C; Barker, S G; Moran, C

    2006-02-01

    A total of 3156 scale row records, comprising 1739 full-sibling records from 30 families from Janamba Croc Farm (NT, Australia) and 1417 parent-offspring records from 19 families from Wildlife Management International, Pty Ltd (NT, Australia), collected at each facility using a different method, were analysed using ASReml. The full-sibling heritability estimate for the Janamba data was 0.37 (SE 0.03). The animal model estimate of heritability for the Wildlife Management International (WMI) data, also based predominantly on full-sibling data, was 0.42 (SE 0.04). The counts from three counting methods were evaluated by regression analysis on 100 individuals and were found to be highly correlated. Using the regression relationship, the WMI data were transformed and pooled with the Janamba data to give an animal model heritability estimate of 0.42 (SE 0.04). A multitrait analysis revealed negligible correlations (both phenotypical and genetical) between hatchling size traits and the number of scale rows. There is ample genetic variation to incorporate this trait into a genetic improvement programme for farmed saltwater crocodiles.

  5. Quantitative analysis of production traits in saltwater crocodiles (Crocodylus porosus): I. reproduction traits.

    PubMed

    Isberg, S R; Thomson, P C; Nicholas, F W; Barker, S G; Moran, C

    2005-12-01

    Repeatability and phenotypic correlations were estimated for saltwater crocodile reproductive traits. No pedigree information was available to estimate heritability or genetic correlations, because the majority of breeder animals on farms were wild-caught. Moreover, as the age of the female breeders could not be accounted for, egg-size measurements were used as proxies. The reproductive traits investigated were clutch size (total number of eggs laid), number of viable eggs, number of eggs that produced a live, healthy hatchling, hatchability, average snout-vent length of the hatchlings and time of nesting. A second data set was also created comprising binary data of whether or not the female nested. Repeatability estimates ranged from 0.24 to 0.68 for the measurable traits, with phenotypic correlations ranging from -0.15 to 0.86. Repeatability for whether a female nested or not was 0.58 on the underlying scale. Correlations could not be estimated between the measurement and binary traits because of confounding. These estimates are the first published for crocodilian reproduction traits.

  6. Quantitative analysis of production traits in saltwater crocodiles (Crocodylus porosus): III. juvenile survival.

    PubMed

    Isberg, S R; Thomson, P C; Nicholas, F W; Barker, S G; Moran, C

    2006-02-01

    Mortality records of 1302 juvenile crocodiles were available for analysis. Crocodiles that were slaughtered during this study were treated as censored (n = 2151). Additionally, records from animals that had neither died nor been slaughtered, i.e. were still alive in the production system (n = 1582), were censored at the last date of data collection. There were a total of 3733 censored records. The data were all full-sib records from 29 parental pairs from Janamba Croc Farm (Northern Territory, Australia), collected over nine consecutive years. Data were analysed using an extension of Cox's proportional hazards model to include frailty (random) terms to account for genetic effects. Heritability of log survival time for juvenile crocodile survival was 0.15 (SE 0.04). The probability of a juvenile crocodile surviving to day 400 was estimated to be only 51%. These results are the first to quantify juvenile survival in a captive breeding situation. Also, this is the first heritability estimate of crocodile survival and is a fundamental element in the development of a genetic improvement programme.

  7. Comparative NMR studies of diffusional water permeability of red blood cells from different species: XVIII platypus (Ornithorhynchus anatinus) and saltwater crocodile (Crocodylus porosus).

    PubMed

    Benga, Gheorghe; Chapman, Bogdan E; Cox, Guy C; Kuchel, Philip W

    2010-07-01

    As part of a programme of comparative measurements of Pd (diffusional water permeability) the RBCs (red blood cells) from an aquatic monotreme, platypus (Ornithorhynchus anatinus), and an aquatic reptile, saltwater crocodile (Crocodylus porosus) were studied. The mean diameter of platypus RBCs was estimated by light microscopy and found to be approximately 6.3 microm. Pd was measured by using an Mn2+-doping 1H NMR (nuclear magnetic resonance) technique. The Pd (cm/s) values were relatively low: approximately 2.1 x 10(-3) at 25 degrees C, 2.5 x 10(-3) at 30 degrees C, 3.4 x 10(-3) at 37 degrees C and 4.5 at 42 degrees C for the platypus RBCs and approximately 2.8 x 10(-3) at 25 degrees C, 3.2 x 10(-3) at 30 degrees C, 4.5 x 10(-3) at 37 degrees C and 5.7 x 10(-3) at 42 degrees C for the crocodile RBCs. In parallel with the low water permeability, the Ea,d (activation energy of water diffusion) was relatively high, approximately 35 kJ/mol. These results suggest that "conventional" WCPs (water channel proteins), or AQPs (aquaporins), are probably absent from the plasma membranes of RBCs from both the platypus and the saltwater crocodile.

  8. Steroidogenic enzyme activity and ovarian differentiation in the saltwater crocodile, Crocodylus porosus.

    PubMed

    Smith, C A; Joss, J M

    1994-02-01

    It has been hypothesized that steroid hormone production is involved in sexual differentiation of the gonads in reptiles with temperature-dependent sex determination. We have therefore examined steroidogenic enzymes and ovarian differentiation in Crocodylus porosus embryos incubated at 30 degrees, a temperature producing 100% female hatchlings. delta 5-3 beta-Hydroxysteroid dehydrogenase (3 beta-HSD) activity was detected only in the adrenal gland before, during, and after the period of ovary differentiation. The same pattern was observed during testis differentiation in embryos incubated at 32 degrees (predominantly male-producing). At no stage was 3 beta-HSD activity detected in the gonads. The tritiated water assay was used to measure aromatase enzyme activity in the gonad-adrenal-mesonephric complex (GAM) during development at 30 degrees C. Aromatase activity in the GAM increased during the period of ovary differentiation. In female C. porosus hatchlings, 85% of the aromatase activity within the GAM was derived from the ovary, 10% from the adrenal, and 5% from the regressing mesonephros. The aromatase inhibitors aminoglutethimide and 4-hydroxyandrostenedione significantly reduced aromatase activity in female hatchling GAMs. In some stage 25 embryos incubated at 32.5 degrees, aromatase activity was low in testes and high in ovaries. These observations show that urogenital tissues of C. porosus are steroidogenically active during gonadal differentiation and that increased aromatase enzyme activity accompanies ovary development at 30 degrees. Steroid synthesis in the GAM of C. porosus embryos may involve interaction between the adrenal glands and the gonads.

  9. Sequence analysis and characterisation of virally induced viperin in the saltwater crocodile (Crocodylus porosus).

    PubMed

    Milic, Natalie L; Davis, Steven; Carr, Jillian M; Isberg, Sally; Beard, Michael R; Helbig, Karla J

    2015-07-01

    A number of pathogens have been detected in crocodiles, however little is known about their ability to control these pathogens. The interferon stimulated gene (ISG), viperin, has gained attention recently as an important host protein involved in multiple arms of the immune response. Viperin in concert with a number of other ISGs was upregulated in response to viral nucleic acid mimics and sendai virus in the C. porosus cell line, LV-1, indicating an intact early innate response to viral infection in these animals for the first time. Viperin was cloned from the LV-1 cell line and shown to have similar localisation patterns as human viperin, as well as demonstrating extremely high conservation with the human orthologue, excepting at the N-terminus. Interestingly, C. porosus viperin was also able to inhibit Dengue virus replication in vitro, showing a high level of intact functionality for this protein across divergent animal species, and perhaps demonstrating its importance in the early innate response to pathogens in the animal kingdom.

  10. The Australian saltwater crocodile (Crocodylus porosus) provides evidence that the capacitation of spermatozoa may extend beyond the mammalian lineage.

    PubMed

    Nixon, Brett; Anderson, Amanda L; Smith, Nathan D; McLeod, Robby; Johnston, Stephen D

    2016-05-11

    Although mammalian spermatozoa only acquire functional maturity as they are conveyed through the male (epididymal maturation) and female (capacitation) reproductive tracts, the degree of post-testicular development necessary to achieve fertilization in other vertebrate species remains far less clear. Indeed, despite reports that the epididymis of birds and reptiles is capable of secreting proteins that bind and modify the sperm surface characteristics, it remains unclear whether capacitation is a pre-requisite for fertilization in these species. Using the ancient reptilian Australian saltwater crocodile as a model, this study was undertaken to explore whether reptile sperm do undergo capacitation-like changes following ejaculation. Our studies revealed that crocodile spermatozoa experienced a rapid and sustained, cyclic-AMP mediated increase in progressive motility following incubation under conditions optimized for the induction of capacitation in mammalian species such as the mouse and human. This response was coupled with elevated levels of phosphorylation associated with both protein kinase A and tyrosine kinase substrates, the latter of which were predominantly localized within the sperm flagellum. In findings that also accord with mammalian spermatozoa, we confirmed a homologue of outer dense fibre 2 as one of the principal substrates for tyrosine phosphorylation. Overall, our findings support the concept that crocodile spermatozoa do undergo a process that is homologous to capacitation in preparation for fertilization of an ovum.

  11. Reference levels for corticosterone and immune function in farmed saltwater crocodiles (Crocodylus porosus) hatchlings using current Code of Practice guidelines.

    PubMed

    Finger, John W; Thomson, Peter C; Adams, Amanda L; Benedict, Suresh; Moran, Christopher; Isberg, Sally R

    2015-02-01

    To determine reference levels for on-farm stressors on immune responsiveness and growth rate, 253 hatchling crocodiles from 11 known breeding pairs were repeatedly measured and blood sampled during their first year. Plasma corticosterone (CORT) was used to quantify baseline stress levels in captive animals and were found to be lower (mean 1.83±SE 0.16 ng/mL) than previously reported in saltwater crocodile hatchlings. Two tests of immune function were also conducted. Innate constitutive immunity was assessed using bacterial killing assays (BKA) against two bacterial species: Escherichia coli and Providencia rettgeri, whereby the latter causes considerable economic loss to industry from septicaemic mortalities. Although the bactericidal capabilities were different at approximately 4 months old (32±3% for E. coli and 16±4% for P. rettgeri), the differences had disappeared by approximately 9 months old (58±2% and 68±6%, respectively). To assess immune responsiveness to a novel antigen, the inflammatory swelling response caused by phytohaemagglutinin (PHA) injection was assessed but was only significantly different between Samplings 1 and 3 (5% LSD). There were no significant clutch effects for CORT or PHA but there were for both BKA traits. CORT was not significantly associated with growth (head length) or the immune parameters except for P. rettgeri BKA where higher CORT levels were associated with better bactericidal capability. As such, these results suggest that the crocodiles in this study are not stressed, therefore endorsing the management strategies adopted within the Australian industry Code of Practice.

  12. The effects of environmental temperature, hypoxia, and hypercapnia on the breathing pattern of saltwater crocodiles (Crocodylus porosus).

    PubMed

    Munns, S L; Frappell, P B; Evans, B K

    1998-01-01

    This study aimed to describe the effects of change in environmental temperature, hypoxia, and hypercapnia on the breathing pattern of Crocodylus porosus. Increased environmental temperature, hypoxia, and hypercapnia each caused an increase in minute ventilation and changes in breathing pattern. Breathing frequency increased and the duration of the nonventilatory period decreased in response to all three conditions. Under hypercapnia tidal volume also increased, with no change in rate of inspiration. The number of breaths per breathing burst decreased with increased temperature but remained unaltered under hypoxia. Hypercapnia reduced the number of breaths per burst at 20 degrees C, but the number did not decrease further at 30 degrees C. The results support the idea that the responses to increased temperature, hypoxia, and hypercapnia are under separate control but that some effects of hypercapnia and temperature may involve a common regulatory pathway.

  13. Crocodylus acutus (American Crocodile). Long distance juvenile movement

    USGS Publications Warehouse

    Crespo, Rafael; Beauchamp, Jeffrey S.; Mazzotti, Frank; Cherkiss, Michael S.

    2015-01-01

    Crocodylus acutus (American Crocodile) is the most widely distributed New World crocodilian species with its range extending from Peru in the south to the southern tip of peninsular Florida in the north. Crocodylus acutus occupies primarily coastal brackish water habitat, however it also occurs in freshwater to hypersaline habitats (Thorbjarnarson 2010. In Crocodiles. Status Survey and Conservation Action Plan. [Third Edition], American Crocodile Crocodylus acutus, pp. 46–53 S.C. Manolis and C. Stevenson. Crocodile Specialist Group, Darwin). There is limited literature on long distance movements of juvenile crocodilians worldwide and no literature on juvenile crocodiles in Florida. However, adult C. acutus in Florida have been documented to make seasonal movements of 5–15 km from preferred foraging habitat to nesting beaches (Mazzotti 1983. The Ecology of Crocodylus acutus in Florida. PhD Dissertation. The Pennsylvania State University, University Park, Pennsylvania. 161pp), and one adult was documented making a 35 km trip from her nest site to preferred foraging habitat (Cherkiss et. al. 2006. Herpetol. Rev. 38:72–73). Rodda (1984. Herpetologica 40:444–451) reported on juvenile C. acutus movement in Gatun Lake, Panama, and found that juveniles stayed within 1 km of their nest site for the first month. Movements of juvenile Crocodylus porosus (Saltwater Crocodile) in a river system in Northern Australia showed a maximum movement of 38.9 km from a known nest site, with the majority of the crocodiles staying within 15.6 km downstream to 6.8 km upstream (Webb and Messel 1978. Aust. Wildlife Res. 5:263–283). Juvenile movement of Crocodylus niloticus (Nile Crocodile) in Lake Ngezi, Zimbabwe showed crocodiles restricted their movements from 1.0 km up to 4.5 km through the wet and dry seasons (Hutton 1989. Am. Zool. 29:1033–1049). Long distance movements of alligators were recorded for sizes ranging from 28 cm to 361 cm in a coastal refuge in Louisiana, where

  14. An outbreak of chlamydiosis in farmed Indopacific crocodiles (Crocodylus porosus).

    PubMed

    Huchzermeyer, F W; Langelet, E; Putterill, J F

    2008-06-01

    An outbreak of chlamydiosis was diagnosed in hatchling and juvenile Indopacific crocodiles (Crocodylus porosus) on a crocodile farm in Papua New Guinea. The outbreak was characterised by high mortality with hepatitis and exudative conjunctivitis. The agent appears to have been introduced with live wild-caught crocodiles, which are purchased routinely by the farm. Improved quarantine procedures and treatment with tetracycline led to a rapid reduction of losses on the farm.

  15. Comparative Genome Analyses Reveal Distinct Structure in the Saltwater Crocodile MHC

    PubMed Central

    Jaratlerdsiri, Weerachai; Deakin, Janine; Godinez, Ricardo M.; Shan, Xueyan; Peterson, Daniel G.; Marthey, Sylvain; Lyons, Eric; McCarthy, Fiona M.; Isberg, Sally R.; Higgins, Damien P.; Chong, Amanda Y.; John, John St; Glenn, Travis C.; Ray, David A.; Gongora, Jaime

    2014-01-01

    The major histocompatibility complex (MHC) is a dynamic genome region with an essential role in the adaptive immunity of vertebrates, especially antigen presentation. The MHC is generally divided into subregions (classes I, II and III) containing genes of similar function across species, but with different gene number and organisation. Crocodylia (crocodilians) are widely distributed and represent an evolutionary distinct group among higher vertebrates, but the genomic organisation of MHC within this lineage has been largely unexplored. Here, we studied the MHC region of the saltwater crocodile (Crocodylus porosus) and compared it with that of other taxa. We characterised genomic clusters encompassing MHC class I and class II genes in the saltwater crocodile based on sequencing of bacterial artificial chromosomes. Six gene clusters spanning ∼452 kb were identified to contain nine MHC class I genes, six MHC class II genes, three TAP genes, and a TRIM gene. These MHC class I and class II genes were in separate scaffold regions and were greater in length (2–6 times longer) than their counterparts in well-studied fowl B loci, suggesting that the compaction of avian MHC occurred after the crocodilian-avian split. Comparative analyses between the saltwater crocodile MHC and that from the alligator and gharial showed large syntenic areas (>80% identity) with similar gene order. Comparisons with other vertebrates showed that the saltwater crocodile had MHC class I genes located along with TAP, consistent with birds studied. Linkage between MHC class I and TRIM39 observed in the saltwater crocodile resembled MHC in eutherians compared, but absent in avian MHC, suggesting that the saltwater crocodile MHC appears to have gene organisation intermediate between these two lineages. These observations suggest that the structure of the saltwater crocodile MHC, and other crocodilians, can help determine the MHC that was present in the ancestors of archosaurs. PMID:25503521

  16. Comparative genome analyses reveal distinct structure in the saltwater crocodile MHC.

    PubMed

    Jaratlerdsiri, Weerachai; Deakin, Janine; Godinez, Ricardo M; Shan, Xueyan; Peterson, Daniel G; Marthey, Sylvain; Lyons, Eric; McCarthy, Fiona M; Isberg, Sally R; Higgins, Damien P; Chong, Amanda Y; John, John St; Glenn, Travis C; Ray, David A; Gongora, Jaime

    2014-01-01

    The major histocompatibility complex (MHC) is a dynamic genome region with an essential role in the adaptive immunity of vertebrates, especially antigen presentation. The MHC is generally divided into subregions (classes I, II and III) containing genes of similar function across species, but with different gene number and organisation. Crocodylia (crocodilians) are widely distributed and represent an evolutionary distinct group among higher vertebrates, but the genomic organisation of MHC within this lineage has been largely unexplored. Here, we studied the MHC region of the saltwater crocodile (Crocodylus porosus) and compared it with that of other taxa. We characterised genomic clusters encompassing MHC class I and class II genes in the saltwater crocodile based on sequencing of bacterial artificial chromosomes. Six gene clusters spanning ∼452 kb were identified to contain nine MHC class I genes, six MHC class II genes, three TAP genes, and a TRIM gene. These MHC class I and class II genes were in separate scaffold regions and were greater in length (2-6 times longer) than their counterparts in well-studied fowl B loci, suggesting that the compaction of avian MHC occurred after the crocodilian-avian split. Comparative analyses between the saltwater crocodile MHC and that from the alligator and gharial showed large syntenic areas (>80% identity) with similar gene order. Comparisons with other vertebrates showed that the saltwater crocodile had MHC class I genes located along with TAP, consistent with birds studied. Linkage between MHC class I and TRIM39 observed in the saltwater crocodile resembled MHC in eutherians compared, but absent in avian MHC, suggesting that the saltwater crocodile MHC appears to have gene organisation intermediate between these two lineages. These observations suggest that the structure of the saltwater crocodile MHC, and other crocodilians, can help determine the MHC that was present in the ancestors of archosaurs.

  17. External injuries of Morelet's crocodile Crocodylus moreletii in Campeche, Mexico.

    PubMed

    Padilla, Sergio E; Weber, Manuel

    2016-07-07

    Analysis of external injuries in captive and free-ranging Morelet's crocodiles Crocodylus moreletii was performed in the northern wetlands of Campeche, Mexico. From March to September of 2007, a total of 52 free-ranging and 51 captive Morelet's crocodiles were studied. Captive crocodiles presented significantly more injuries. Sixteen free-ranging crocodiles presented some type of lesion, mostly superficial abrasions. Nineteen captive crocodiles presented lesions, mostly incisions from agonistic interactions. Overall, the injuries with highest prevalence were the incisions. The tail was the most frequently injured body region. Injuries were more common in adults than in other size classes. Conversely, the presence of lesions caused by the parasite Paratrichosoma spp. was greater in crocodiles captured in the coastal channels (mangrove habitat). The information presented here is important to understand some of the effects of individual interactions and to foresee and manage the consequences of conservation and management activities of crocodile populations.

  18. Remarkable movements of an American crocodile (Crocodylus acutus) in Florida

    USGS Publications Warehouse

    Cherkiss, Michael S.; Mazzotti, Frank J.; Hord, Lindsey; Aldecoa, Mario

    2014-01-01

    Here we present the remarkable movements of an individual Crocodylus acutus (American Crocodile) over a 14-year period. The crocodile was originally marked in Homestead, FL as a young-of-the-year in 1999, and was later recaptured multiple times more than 388 km away along the southwest coast of Florida. After several relocations and numerous sightings, this individual who has become known as Yellow Number 1 was found back within the same canal system in which it was first captured.

  19. Functional and morphological plasticity of crocodile (Crocodylus porosus) salt glands.

    PubMed

    Cramp, Rebecca L; Meyer, Edward A; Sparks, Nicole; Franklin, Craig E

    2008-05-01

    The estuarine crocodile, Crocodylus porosus, inhabits both freshwater and hypersaline waterways and maintains ionic homeostasis by excreting excess sodium and chloride ions via lingual salt glands. In the present study, we sought to investigate the phenotypic plasticity, both morphological and functional, in the lingual salt glands of the estuarine crocodile associated with chronic exposure to freshwater (FW) and saltwater (SW) environments. Examination of haematological parameters indicated that there were no long-term disruptions to ionic homeostasis with prolonged exposure to SW. Maximal secretory rates from the salt glands of SW-acclimated animals (100.8+/-14.7 micromol 100 g(-0.7) body mass h(-1)) were almost three times greater than those of FW-acclimated animals (31.6+/-6.2 micromol 100 g(-0.7) body mass h(-1)). There were no differences in the mass-specific metabolic rate of salt gland tissue slices from FW- and SW-acclimated animals (558.9+/-49.6 and 527.3+/-142.8 microl O(2) g(-1) h(-1), respectively). Stimulation of the tissue slices from SW-acclimated animals by methacholine resulted in a 33% increase in oxygen consumption rate. There was no significant increase in the metabolic rate of tissues from FW-acclimated animals in response to methacholine. Morphologically, the secretory cells from the salt glands of SW-acclimated animals were larger than those of FW-acclimated animals. In addition, there were significantly more mitochondria per unit volume in secretory tissue from SW-acclimated animals. The results from this study demonstrate that the salt glands of C. porosus are phenotypically plastic, both morphologically and functionally and acclimate to changes in environmental salinity.

  20. Glucocorticoids, thyroid hormones, and iodothyronine deiodinases in embryonic saltwater crocodiles.

    PubMed

    Shepherdley, Caroline A; Daniels, Christopher B; Orgeig, Sandra; Richardson, Samantha J; Evans, Barbara K; Darras, Veerle M

    2002-11-01

    We investigated the relationship between glucocorticoids, thyroid hormones, and outer ring and inner ring deiodinases (ORD and IRD) during embryonic development in the saltwater crocodile (Crocodylus porosus). We treated the embryos with the synthetic glucocorticoid dexamethasone (Dex), 3,3',5-triiodothyronine (T(3)), and a combination of these two hormones (Dex + T(3)). The effects of these treatments were specific in different tissues and at different stages of development and also brought about changes in plasma concentrations of free thyroid hormones and corticosterone. Administration of Dex to crocodile eggs resulted in a decrease in 3,3',5,5'-tetraiodothyronine (T(4)) ORD activities in liver and kidney microsomes, and a decrease in the high-K(m) rT(3) ORD activity in kidney microsomes, on day 60 of incubation. Dex treatment increased the T(4) ORD activity in liver microsomes, but not kidney microsomes, on day 75 of incubation. Dex administration decreased T(3) IRD activity in liver microsomes. However, this decrease did not change plasma-free T(3) concentrations, which suggests that free thyroid hormone levels are likely to be tightly regulated during development.

  1. Ocular disease in American crocodiles (Crocodylus acutus) in Costa Rica.

    PubMed

    Rainwater, Thomas R; Millichamp, Nicholas J; Barrantes, Luz Denia Barrantes; Barr, Brady R; Montero, Juan R Bolaños; Platt, Steven G; Abel, Mike T; Cobb, George P; Anderson, Todd A

    2011-04-01

    Beginning in early 2006, an ocular disease of unknown etiology was routinely observed in American crocodiles (Crocodylus acutus) inhabiting the highly polluted Tarcoles River in west-central Costa Rica. We examined the nature and incidence of ocular disease in Tarcoles crocodiles and assessed the possible association between the disease and accumulation of chemical pollutants in diseased individuals. During 12-15 September and 12-13 December 2007, crocodiles were captured and examined for ocular disease and sampled to determine environmental contaminant accumulation. Three of 11 (27.3%) crocodiles captured (all males) exhibited unilateral ocular disease, primarily characterized by corneal opacity and scarring, anterior synechia, and phthisis bulbi. Multiple pollutants were detected in crocodile caudal scutes (organochlorine pesticides [OCPs] and metals), crocodile blood (OCPs), and sediments (OCPs and metals) from the Tarcoles, but no associations were found between contaminant accumulation and the incidence of eye disease. On the basis of the limited number of diseased animals examined and the potential exposure of crocodiles to pathogens and other pollutants not targeted in this study, we cannot rule out infection or chemical toxicosis as causes of the eye lesions. However, circumstantial evidence suggests that the observed ocular disease is likely the result of injury-induced trauma (and possibly secondary infection) inflicted during aggressive encounters (e.g., territorial combat) among large adult crocodiles living at relatively high densities.

  2. Aeromonas hydrophila-associated septicemia in captive crocodiles (Crocodylus johnstoni and Crocodylus porosus).

    PubMed

    Roh, Yoon-Seok; Park, Heejin; Cho, Hyun-Ung; Cho, Ara; Islam, Mohammad Rafiqul; Cho, Ho-Seong; Lim, Chae Woong; Kim, Bumseok

    2011-12-01

    Five 25-yr-old crocodiles (Crocodylus johnstoni and Crocodylus porosus) were diagnosed with Aeromonas hydrophila-associated septicemia accelerated by improper thermoregulation. At necropsy, pulmonary congestion and pleural effusion were the main lesions in the thorax. Necrotizing enteritis, intestinal hemorrhage, fibrinous serositis, hepatitis, and pancreatitis were observed in the abdominal cavities of all five crocodiles. Aeromonas hydrophila was identified in the pleural effusions and abdominal ascites of all necropsied crocodiles by using an API system 20NE. Aeromonas hydrophila infection and evaluation of virulence were confirmed by polymerase chain reaction targeting the 16S rRNA and extracellular hemolysin gene. The crocodiles in the present case were housed in an indoor facility at a private zoo that failed to optimize land and water portions of the enclosure, exposing the animals to impeded thermoregulation, and it is suggested that the pathogenesis was accelerated by the improper thermoregulation-induced stress. This is the first description of A. hydrophila pathogenicity associated with impeded thermoregulation in reptiles.

  3. Organochlorine contaminants in Morelet's crocodile (Crocodylus moreletii) eggs from Belize.

    PubMed

    Wu, T H; Rainwater, T R; Platt, S G; McMurry, S T; Anderson, T A

    2000-03-01

    Non-viable eggs of Morelet's crocodile (Crocodylus moreletii) were collected from Gold Button (GBL) and New River lagoons (NRL) in northern Belize and screened for organochlorine (OC) compounds using gas chromatography (GC) with electron capture detection (ECD). All egg samples from both lagoons (n = 24) tested positive for one or more OCs. Primary contaminants were p,p-DDE and methoxychlor, detected in 100% and 29% of the eggs examined, respectively. Concentrations of individual OC contaminants ranged from 1 ppb (ng chemical/g egg) to > 0.5 ppm (microgram chemical/g egg). Total concentrations of OCs (sum of all OCs) for one egg collected from a nest at GBL reached as high as 0.7 ppm. Sediment samples from both lagoons also tested positive for OCs (lindane, aldrin, methoxychlor, heptachlor epoxide, p,p-DDT, among others). Nest media (soil and plant material) collected from crocodile nests at GBL were positive for p,p-DDT, methoxychlor, aldrin, endosulfan II, and endrin aldehyde. Based on the 24 egg samples analyzed to date, crocodiles from both lagoons are being exposed to OCs. Such exposure may present a health threat to populations of crocodiles in Central America.

  4. Inappropriate feeding practice favors the transmission of Trichinella papuae from wild pigs to saltwater crocodiles in Papua New Guinea.

    PubMed

    Pozio, Edoardo; Owen, Ifor L; Marucci, Gianluca; La Rosa, Giuseppe

    2005-02-28

    The recent discovery of Trichinella zimbabwensis in farmed crocodiles (Crocodilus niloticus) of Zimbabwe and its ability to infect mammals, and the development of both T. zimbabwensis and Trichinella papuae in experimentally infected reptiles led to an investigation of Trichinella infection in saltwater crocodiles (Crocodylus porosus) and in wild pigs (Sus scrofa) of Papua New Guinea, to see if T. papuae also, is present in both cold- and warm-blooded animals. Of 222 crocodiles examined, 47 animals (21.2%), all from Kikori, Gulf Province, were positive for non-encapsulated larvae in the muscles. The greatest number of larvae was found usually in the biceps, with an average of 7 larvae/g. One isolate from a crocodile infected successfully both laboratory rats and mice. Of 81 wild pigs examined, 9 from Bensbach river area (Western Province) and 1 from Kikori area (Gulf Province) were positive for non-encapsulated larvae in the muscles. Trichinella larvae from both saltwater crocodiles and wild pigs have been identified by multiplex-PCR analysis as T. papuae. The sequence analysis of the region within the large subunit ribosomal DNA, known as the expansion segment V, has shown the presence of a molecular marker distinguishing T. papuae isolates of Bensbach river area from those of Kikori area. This marker could be useful to trace back the geographical origin of the infected animal. The epidemiological investigation carried out in the Kikori area has shown that local people catch young crocodiles in the wild and keep them in holding pens for several months, before sending them to the crocodile farm in Lae (Morobe Province). They feed the crocodiles primarily with wild pig meat bought at the local market and also with fish. These results stress the importance of using artificial digestion for routinely screening of swine and crocodiles, and of adopting measures for preventing the spread of infection, such as the proper disposal of carcasses and the adequate freezing of

  5. Thermal relations of large crocodiles, Crocodylus porosus, free-ranging in a naturalistic situation

    PubMed Central

    Grigg, G. C.; Seebacher, F.; Beard, L. A.; Morris, D.

    1998-01-01

    We monitored behaviour and environmental and body temperatures (Tb) in summer and winter in 11 salt-water crocodiles (Crocodylus porosus), of body mass 32 to 1010kg, free-ranging in naturalistic captivity in northern Australia. We found pronounced daily cycles in air and water temperatures in both winter (16 to 33 degrees C and 20 to 31degrees C, respectively) and summer (21 to 45 degrees C and 24 to 36 degrees C, respectively). In winter, crocodiles exposed themselves to the sun during the day and stayed in the water at night. In summer, they remained in the water during the day and emerged onto land at night. Body temperature showed a daily cycle the amplitude of which decreased with increasing mass, from 3.5 degrees C (mass 32kg) to 1.0 degrees C (660kg) in summer, and from 3.5 degrees C (42kg) to 1.4 degrees C (1010kg) in winter. Underlying the daily cycles in Tb were intermediate (10 to 13 day, tidal?) and seasonal cycles. Overall, values of modal Tb ranged from 25.1 to 28.7 degrees C in winter and from 28.4 to 33.6 degrees C in summer, trending upwards with body size. This pattern of continuous oscillations in Tb, with no daily plateau, is conspicuously different from that seen in crocodilians of small sizes and from the pattern usually regarded as typical of reptiles in general.

  6. Evolutionary history of Cuban crocodiles Crocodylus rhombifer and Crocodylus acutus inferred from multilocus markers.

    PubMed

    Milián-García, Yoamel; Venegas-Anaya, Miryam; Frias-Soler, Roberto; Crawford, Andrew J; Ramos-Targarona, Roberto; Rodríguez-Soberón, Roberto; Alonso-Tabet, Manuel; Thorbjarnarson, John; Sanjur, Oris I; Espinosa-López, Georgina; Bermingham, Eldredge

    2011-07-01

    Among crocodilians, Crocodylus rhombifer is one of the world's most endangered species with the smallest natural distribution. In Cuba, this endemic species coexists with the American crocodile (Crocodylus acutus). Hybridization between these two species is well known in captivity and might occur in the wild, but has never been demonstrated genetically. Here, we combined molecular data with environmental, geographic, and fossil data to infer the evolutionary history of Crocodylus in the Cuban Archipelago, and to evaluate genealogical support for species boundaries. We analyzed seven microsatellite loci plus DNA sequence data from nuclear (RAG-1) and mitochondrial (cytochrome b and cytochrome oxidase I) genes from 89 wild-caught individuals in Cuba, Grand Cayman Island, Jamaica, and Central America, and two samples from zoo collections. Microsatellites showed evidence of introgression, suggesting potential hybridization among Cuban groups. In Cuba, C. acutus contained one mitochondrial DNA (mtDNA) haplotype, whereas C. rhombifer contained two haplotypes. MtDNA data showed that C. acutus is paraphyletic with respect to C. rhombifer, revealing 1% sequence divergence between species within Cuba vs. 8% divergence between Cuban forms and mainland C. acutus. We suggest that hybridization has been a historical as well as a current phenomenon between C. acutus and C. rhombifer. These findings suggest that long-term conservation of crocodiles in Cuba will require identification of genetically pure and hybrid individuals, and a decrease in anthropogenic activities. We also recommend more extensive morphological and genetic analyses of Cuban population to establish clear boundaries of the hybrid zone between C. acutus and C. rhombifer.

  7. Genetic characterization of captive Cuban crocodiles (Crocodylus rhombifer) and evidence of hybridization with the American crocodile (Crocodylus acutus).

    PubMed

    Weaver, Jeremy P; Rodriguez, David; Venegas-Anaya, Miryam; Cedeño-Vázquez, José Rogelio; Forstner, Michael R J; Densmore, Llewellyn D

    2008-12-01

    There is a surprising lack of genetic data for the Cuban crocodile (Crocodylus rhombifer), especially given its status as a critically endangered species. Samples from captive individuals were used to genetically characterize this species in comparison with other New World crocodilians. Partial mitochondrial sequence data were generated from cyt-b (843 bp) and the tRNA(Pro)- tRNA(Phe)-D-loop region (442 bp). Phylogenetic analyses were performed by generating maximum parsimony, maximum likelihood, and Bayesian-based topologies. In addition, in an effort to identify species-specific alleles, ten polymorphic microsatellite loci were genotyped. Distance and model-based clustering analyses were performed on microsatellite data, in addition to a model-based assignment of hybrid types. Both mitochondrial and nuclear markers identified two distinct C. rhombifer genetic sub-clades (alpha and beta); and microsatellite analyses revealed that most admixed individuals were F(2) hybrids between C. rhombifer-alpha and the American crocodile (C. acutus). All individuals in the C. rhombifer-beta group were morphologically identified as C. acutus and formed a distinct genetic assemblage. J. Exp. Zool. 309A:649-660, 2008. (c) 2008 Wiley-Liss, Inc.

  8. Normal haematology and blood biochemistry of wild Nile crocodiles (Crocodylus niloticus) in the Okavango Delta, Botswana.

    PubMed

    Lovely, C J; Pittman, J M; Leslie, A J

    2007-09-01

    Wild Nile crocodiles (Crocodylus niloticus) of various size classes were captured in the Okavango Delta, Botswana. Blood was collected from the post occipital sinus and used for the determination of a wide range of haematological and biochemical parameters. These values were compared between the sexes and between 3 size classes. The values were also compared with the limited data available from farmed Nile crocodiles, as well as from other wild Nile crocodiles. The Okavango crocodiles were comparatively anaemic, and had comparatively low total protein and blood glucose levels. There was a high prevalence of Hepatozoon pettiti infection, however, there was no significant difference in haematological values between the infected and uninfected crocodiles. The values reported here will be useful in diagnostic investigations in both zoo and farmed Nile crocodiles.

  9. Oral and cloacal microflora of wild crocodiles Crocodylus acutus and C. moreletii in the Mexican Caribbean.

    PubMed

    Charruau, Pierre; Pérez-Flores, Jonathan; Pérez-Juárez, José G; Cedeño-Vázquez, J Rogelio; Rosas-Carmona, Rebeca

    2012-02-17

    Bacterial cultures and chemical analyses were performed from cloacal and oral swabs taken from 43 American crocodiles Crocodylus acutus and 28 Morelet's crocodiles C. moreletii captured in Quintana Roo State, Mexico. We recovered 47 bacterial species (28 genera and 14 families) from all samples with 51.1% of these belonging to the family Enterobacteriaceae. Fourteen species (29.8%) were detected in both crocodile species and 18 (38.3%) and 15 (31.9%) species were only detected in American and Morelet's crocodiles, respectively. We recovered 35 bacterial species from all oral samples, of which 9 (25.8%) were detected in both crocodile species. From all cloacal samples, we recovered 21 bacterial species, of which 8 (38.1%) were detected in both crocodile species. The most commonly isolated bacteria in cloacal samples were Aeromonas hydrophila and Escherichia coli, whereas in oral samples the most common bacteria were A. hydrophila and Arcanobacterium pyogenes. The bacteria isolated represent a potential threat to crocodile health during conditions of stress and a threat to human health through crocodile bites, crocodile meat consumption or carrying out activities in crocodile habitat. We especially warn about the presence of Salmonella arizonae and S. typhi, which cause enteritis and septicemia in crocodiles and salmonellosis and typhoid fever in humans. The risk of bacterial contamination from crocodiles to humans could increase in the future because of the accelerated destruction of crocodile habitat, which could lead to an augmentation of human-crocodile interactions. Information on bacterial diversity reported here could help in the choice of antibacterial products in case of infections that are of crocodile origin.

  10. Encephalitozoon hellem Infection in a Captive Juvenile Freshwater Crocodile (Crocodylus johnstoni).

    PubMed

    Scheelings, T F; Slocombe, R F; Crameri, S; Hair, S

    2015-11-01

    Microsporidiosis is reported rarely in reptiles and has never been reported in any species of crocodilian. Microsporidiosis was diagnosed histologically in a juvenile captive freshwater crocodile (Crocodylus johnstoni) that was found suddenly dead in its enclosure. Ultrastructural and molecular testing revealed infection to be due to Encephalitozoon hellem. This is the first report of E. hellem infection in any species of reptile.

  11. Crocodile choline from Crocodylus siamensis induces apoptosis of human gastric cancer.

    PubMed

    Mao, Xiao-Mei; Fu, Qi-Rui; Li, Hua-Liang; Zheng, Ya-Hui; Chen, Shu-Ming; Hu, Xin-Yi; Chen, Qing-Xi; Chen, Qiong-Hua

    2017-03-01

    Crocodile choline, an active compound isolated from Crocodylus siamensis, was found to exert potent anti-cancer activities against human gastric cancer cells in vitro and in vivo. Our study revealed that crocodile choline led to cell cycle arrest at the G2/M phase through attenuating the expressions of cyclins, Cyclin B1, and CDK-1. Furthermore, crocodile choline accelerated apoptosis through the mitochondrial apoptotic pathway with the decrease in mitochondrial membrane potential, the increase in reactive oxygen species production and Bax/Bcl-2 ratio, and the activation of caspase-3 along with the release of cytochrome c. In addition, this study, for the first time, shows that Notch pathway is remarkably deregulated by crocodile choline. The combination of crocodile choline and Notch1 short interfering RNA led to dramatically increased cytotoxicity than observed with either agent alone. Notch1 short interfering RNA sensitized and potentiated the capability of crocodile choline to suppress the cell progression and invasion of gastric cancer. Taken together, these data suggested that crocodile choline was a potent progression inhibitor of gastric cancer cells, which was correlated with mitochondrial apoptotic pathway and Notch pathway. Combining Notch1 inhibitors with crocodile choline might represent a novel approach for gastric cancer.

  12. Body condition of Morelet’s Crocodiles (Crocodylus moreletii) from northern Belize

    USGS Publications Warehouse

    Mazzotti, Frank J.; Cherkiss, Michael S.; Brandt, Laura A.; Fujisaki, Ikuko; Hart, Kristen; Jeffery, Brian; McMurry, Scott T.; Platt, Steven G.; Rainwater, Thomas R.; Vinci, Joy

    2012-01-01

    Body condition factors have been used as an indicator of health and well-being of crocodilians. We evaluated body condition of Morelet's Crocodiles (Crocodylus moreletii) in northern Belize in relation to biotic (size, sex, and habitat) and abiotic (location, water level, and air temperature) factors. We also tested the hypothesis that high water levels and warm temperatures combine or interact to result in a decrease in body condition. Size class, temperature, and water level explained 20% of the variability in condition of Morelet's Crocodiles in this study. We found that adult crocodiles had higher condition scores than juveniles/subadults but that sex, habitat, and site had no effect. We confirmed our hypothesis that warm temperatures and high water levels interact to decrease body condition. We related body condition of Morelet's Crocodiles to natural fluctuations in air temperatures and water levels in northern Belize, providing baseline conditions for population and ecosystem monitoring.

  13. Technique for the collection of clear urine from the Nile crocodile (Crocodylus niloticus).

    PubMed

    Myburgh, Jan G; Huchzermeyer, Fritz W; Soley, John T; Booyse, Dirk G; Groenewald, Herman B; Bekker, Lizette C; Iguchi, Taisen; Guillette, Louis J

    2012-07-03

    Urine samples can be a very useful diagnostic tool for the evaluation of animal health. In this article, a simple technique to collect urine from the Nile crocodile (Crocodylus niloticus) was described, based on a similar unpublished technique developed for the American alligator (Alligator mississippiensis) using a canine urinary catheter. With this technique, it was possible to collect relatively clean urine samples from Nile crocodiles of different sizes using canine urinary catheters or small diameter stomach tubes. Based on the gross anatomical features of the cloaca of the Nile crocodile, it was confirmed that urine accumulates in a chamber consisting of the urodeum and coprodeum. Faecal material is stored temporarily in the very short rectum, which is separated from the urinary chamber by the rectocoprodeal sphincter.

  14. Analysis of microsatellites and parentage testing in saltwater crocodiles.

    PubMed

    Isberg, S R; Chen, Y; Barker, S G; Moran, C

    2004-01-01

    Fifteen microsatellite loci were evaluated in farmed saltwater crocodiles for use in parentage testing. One marker (C391) could not be amplied. For the remaining 14, the number of alleles per locus ranged from two to 16, and the observed heterozygosities ranged from 0.219 to 0.875. The cumulative exclusion probability for all 14 loci was .9988. the 11 loci that showed the greatest level of polymorphism were used for parentage testing, with an exclusion probability of .9980. With these 11 markers on 107 juveniles from 16 known breeding pairs, a 5.6% pedigree error rate was detected. This level of pedigree error, if consistent, could have an impact on the accuracy of gentic parameter and breeding value estimation. The usefulness of these markers was also evaluated for assigning parentage in situations where maternity, paternity, or both may not be known. In these situations, a 2% error in parentage assignment was predicted. It is therefore recommended that more micro-satellite markers be used in these situations. The use of these microsatellite markers will broaden the scope of a breeding program, allowing progeny to be tested from adults maintained in large breeding lagoons for selection as future breeding animals.

  15. Surveys of endogenous retroviruses (ERVs) in the freshwater crocodile (Crocodylus johnstoni) suggest that ERVs in Crocodylus spp. vary between species.

    PubMed

    Chong, Amanda Y; Kjeldsen, Shannon R; Gongora, Jaime

    2015-04-01

    Endogenous retroviruses (ERVs) are one of many families of transposable elements present in vertebrate genomes. We have examined the ERV complement of the freshwater crocodile (Crocodylus johnstoni) in order to investigate the diversity of ERVs present and possibility of ERV or retroviral activity in a diseased individual of this species. Amplification and sequencing of the highly conserved retroviral pro-pol domains revealed high levels of sequence variation in these ERVs. Phylogenetic analyses of these ERVs and those previously identified in other crocodilian species suggest that although many crocodilians share the same ERV lineages, the relative numbers of retroelement insertions from each of these lineages may vary greatly between species. The data generated in this study provide evidence for the presence of a unique and varied complement of ERVs in crocodilians. This study has also demonstrated the presence of species-specific evolution in ancient retroviral infections.

  16. Incorporating known sources of uncertainty to determine precautionary harvests of saltwater crocodiles.

    PubMed

    Bradshaw, Corey J A; Fukuda, Yusuke; Letnic, Mike; Brook, Barry W

    2006-08-01

    It has been demonstrated repeatedly that the degree to which regulation operates and the magnitude of environmental variation in an exploited population will together dictate the type of sustainable harvest achievable. Yet typically, harvest models fail to incorporate uncertainty in the underlying dynamics of the target population by assuming a particular (unknown) form of endogenous control. We use a novel approach to estimate the sustainable yield of saltwater crocodile (Crocodylus porosus) populations from major river systems in the Northern Territory, Australia, as an example of a system with high uncertainty. We used multimodel inference to incorporate three levels of uncertainty in yield estimation: (1) uncertainty in the choice of the underlying model(s) used to describe population dynamics, (2) the error associated with the precision and bias of model parameter estimation, and (3) environmental fluctuation (process error). We demonstrate varying strength of evidence for density regulation (1.3-96.7%) for crocodiles among 19 river systems by applying a continuum of five dynamical models (density-independent with and without drift and three alternative density-dependent models) to time series of density estimates. Evidence for density dependence increased with the number of yearly transitions over which each river system was monitored. Deterministic proportional maximum sustainable yield (PMSY) models varied widely among river systems (0.042-0.611), and there was strong evidence for an increasing PMSY as support for density dependence rose. However, there was also a large discrepancy between PMSY values and those produced by the full stochastic simulation projection incorporating all forms of uncertainty, which can be explained by the contribution of process error to estimates of sustainable harvest. We also determined that a fixed-quota harvest strategy (up to 0.2K, where K is the carrying capacity) reduces population size much more rapidly than proportional

  17. Development of an ELISA to detect the humoral immune response to Trichinella zimbabwensis in Nile crocodiles (Crocodylus niloticus).

    PubMed

    Ludovisi, Alessandra; La Grange, Louis Jacobus; Gómez Morales, Maria Angeles; Pozio, Edoardo

    2013-05-20

    Crocodiles are known reservoir hosts of Trichinella papuae and Trichinella zimbabwensis, two zoonotic parasites that also infect mammals. Since commercial crocodile farming represents a key source of income in several countries, it is important to monitor this nematode infection in both farmed crocodiles and in breeding stocks which are frequently introduced from the wild. For this purpose, an indirect ELISA was developed to detect the anti-Trichinella immune response in crocodile sera. New Zealand rabbits were immunized with pooled sera from non-infected farmed crocodiles in the presence of Freund's complete adjuvant. The anti-crocodile serum was then conjugated with horseradish peroxidase. Serum samples from four Nile crocodiles (Crocodylus niloticus) experimentally infected with T. zimbabwensis and from four uninfected crocodiles were used to set up the ELISA. The larval burden per gram of muscle tissue was determined by muscle biopsy. The test was performed on serum samples from an additional 15 experimentally infected crocodiles as well as eight wild Nile crocodiles. Among the 19 experimentally infected crocodiles, seroconversion was observed in 11 animals. The highest antibody response was observed six weeks post infection (p.i.), but in most of these animals, antibodies were not detectable after six weeks p.i. even though live larvae were present in the muscles up to six months p.i.

  18. Microbial flora of frozen tail meat from captive Nile crocodiles (Crocodylus niloticus).

    PubMed

    Madsen, M

    1993-03-01

    Frozen tail meat samples from nine Nile crocodiles (Crocodylus niloticus) were evaluated for microbial numbers and types. Microbial analyses yielded a mean aerobic plate count (APC, 30 degrees C) of 4.86 log cfu/g, a mean coliform count (TC, 37 degrees C) of 3.77 log cfu/g and a mean faecal coliform count (FC, 44 degrees C) of 3.40 log cfu/g. Salmonella was isolated from three samples, and beta-haemolytic streptococci from two samples. Yersinia, Aeromonas, Staphylococcus aureus and Bacillus cereus were not isolated. Typical bacterial genera recovered included Flavobacterium, Pseudomonas, Acinetobacter, Enterobacter, Moraxella, Micrococcus, Staphylococcus and Streptococcus.

  19. Evidence of multiple paternity in Morelet's Crocodile (Crocodylus moreletii) in Belize, CA, inferred from microsatellite markers.

    PubMed

    McVay, John D; Rodriguez, David; Rainwater, Thomas R; Dever, Jennifer A; Platt, Steven G; McMurry, Scott T; Forstner, Michael R J; Densmore, Llewellyn D

    2008-12-01

    Microsatellite data were generated from hatchlings collected from ten nests of Morelet's Crocodile (Crocodylus moreletii) from New River Lagoon and Gold Button Lagoon in Belize to test for evidence of multiple paternity. Nine microsatellite loci were genotyped for 188 individuals from the 10 nests, alongside 42 nonhatchlings from Gold Button Lagoon. Then mitochondrial control region sequences were generated for the nonhatchlings and for one individual from each nest to test for presence of C. acutus-like haplotypes. Analyses of five of the nine microsatellite loci revealed evidence that progeny from five of the ten nests were sired by at least two males. These data suggest the presence of multiple paternity as a mating strategy in the true crocodiles. This information may be useful in the application of conservation and management techniques to the 12 species in this genus, most of which are threatened or endangered.

  20. Microbial quality of frozen Nile crocodile (Crocodylus niloticus) meat samples from three selected farms in Zimbabwe.

    PubMed

    Makanyanga, Tsitsi B; Mutema, Gideon; Mukarati, Norman L; Chikerema, Sylvester M; Makaya, Pious V; Musari, Shuvai; Matope, Gift

    2014-01-17

    Microbial quality of frozen Nile crocodile (Crocodylus niloticus) meat from three farms in Zimbabwe was assessed based on 2051 samples collected for pre-export testing during 2006 to 2011. Data were perused by season and year in terms of aerobic plate (APC), coliform (CC), Escherichia coli (ECC) and Listeria monocytogenes (LMC) counts and the presence of Salmonella spp. The log10-transformed data were compared among the farms and seasons using the Kruskal-Wallis test. Microbial quality of the samples was graded based on the EC No. 2073.2005 criteria for beef. The mean APC and CC for the crocodile meat differed significantly (P=0.000) among the farms with the highest APC (3.2±0.05 log10 cfu/g) and the lowest (2.7±0.05 log10 cfu/g) recorded from farms A and C, respectively. There were no significant differences (P>0.05) in ECC and LMC among the farms, while Salmonella spp. were only isolated from one farm. Although the microbial quality of frozen crocodile meat from these farms was generally within acceptable limits, the isolation of E. coli and Salmonella spp. is of public health concern. Thus, implementing of measures to control the pasteurizing process and to minimize bacterial contamination of crocodile meat after pasteurization need to be carefully considered.

  1. Osmoregulation of the Nile crocodile, Crocodylus niloticus, in Lake St. Lucia, Kwazulu/Natal, South Africa.

    PubMed

    Leslie, A J; Spotila, J R

    2000-07-01

    Nile crocodiles of three age classes, hatched in captivity and reared in fresh water, when exposed acutely to water of 17 and 35 ppt NaCl, suffered marked dehydration, were lethargic, ceased to feed and lost mass. When exposed to gradually increasing salinities (3-35 ppt), with a short acclimation period at each salinity, crocodiles survived, continued to feed and increased in mass and size. All age classes had a relatively constant plasma osmolality across the salinity spectrum. Cloacal urine osmolality varied throughout the acclimation experiment, but did not increase with increasing salinity. No significant increase was found in plasma concentrations of any of the osmolytes. There was a trend of decreasing cloacal urine [Na(+)] and [Cl(-)] and increasing cloacal urine [K(+)] with increased salinity, indicating that urine was not an important route for Na(+) and Cl(-) excretion. Crocodiles exposed to saline conditions maintained relatively constant plasma uric acid concentrations, but urinary uric acid concentrations increased markedly with increasing salinities. This suggests that uric acid is the main constituent of nitrogenous waste excretion in saline exposed Nile crocodiles. As in Crocodylus porosus, C.niloticus has the physiological ability to survive and thrive in periodically hyper-osmotic environments. However, its euryhalinity is restricted, in that acute exposure to sea water leads to dehydration, but with an acclimation period at lower salinities, it survives and thrives in sea water.

  2. Experimental study of blood lead kinetics in estuarine crocodiles (Crocodylus porosus) exposed to ingested lead shot.

    PubMed

    Hammerton, K M; Jayasinghe, N; Jeffree, R A; Lim, R P

    2003-10-01

    A previous study of lead (Pb) contamination in estuarine crocodiles (Crocodylus porosus) in Kakadu National Park, Australia, found elevated Pb levels in bone and flesh from individuals caught in habitats where hunting with lead ammunition had occurred. Lead shot was suspected as the potential source of Pb in these animals. An investigation was designed to determine if crocodiles are capable of retaining and dissolving lead shot in their stomachs and absorbing the ionic Pb into the blood. Four of the six juvenile crocodiles (C. porosus) used in the experiment were fed an initial dose of five or ten lead shot each. Most of the lead shot were retained in the stomach over the 20-week experimental period, as confirmed by stomach lavage and radiography of the stomach region. From 13 to 30% of the original weight of individual lead shot had been eroded in that time. In vitro experiments confirmed that lead shot could be dissolved under conditions simulating those known for the crocodilian stomach. Blood Pb concentrations increased by an order of magnitude within a week after dosing three crocodiles with five lead shot each, and then attained steady-state equilibrium 5-20 weeks after dosing, with blood Pb steady-state levels ranging from 278 to 363 microg/dL. The blood Pb concentration-time curves in these crocodiles followed a one-compartment model with first-order loss kinetics that yielded an apparent biological half-life for Pb in blood of about 3.4 days. Throughout the experiment, the crocodiles remained in apparent good physical condition and displayed no clinical signs of Pb toxicosis. These observations, together with the very high blood Pb levels that were sustained for several months, suggest that crocodilians may possess a relatively high degree of resistance to Pb toxicity.

  3. Blood lead concentrations in free-ranging Nile crocodiles (Crocodylus niloticus) from South Africa.

    PubMed

    Warner, Jonathan K; Combrink, Xander; Myburgh, Jan G; Downs, Colleen T

    2016-07-01

    Generally crocodilians have received little attention with regard to the effects of lead toxicity despite their trophic status as apex, generalist predators that utilize both aquatic and terrestrial habitats, thereby exposing them to a potentially wide range of environmental contaminants. During July-October 2010 we collected whole blood from 34 sub-adult and adult free-ranging Nile crocodiles (Crocodylus niloticus) from three separate populations in northeastern South Africa in order to analyze their blood lead concentrations (BPb). Concentrations ranged from below detectability (<3 μg/dL, n = 8) to 960 μg/dL for an adult male at the Lake St Lucia Estuary. Blood lead concentrations averaged 8.15 μg/dL (SD = 7.47) for females and 98.10 μg/dL (SD = 217.42) for males. Eighteen individuals (53 %) had elevated BPbs (≥10 μg/dL). We assessed 12 general linear models using Akaike's Information Criterion (AIC) and found no significant statistical effects among the parameters of sex, crocodile size and population sampled. On average, crocodiles had higher BPbs at Lake St Lucia than at Ndumo Game Reserve or Kosi Bay, which we attribute to lead sinker ingestion during normal gastrolith acquisition. No clinical effects of lead toxicosis were observed in these crocodiles, even though the highest concentration (960 μg/dL) we report represents the most elevated BPb recorded to date for a free-ranging vertebrate. Although we suggest adult Nile crocodiles are likely tolerant of elevated Pb body burdens, experimental studies on other crocodilian species suggest the BPb levels reported here may have harmful or fatal effects to egg development and hatchling health. In light of recent Nile crocodile nesting declines in South Africa we urge further BPb monitoring and ecotoxicology research on reproductive females and embryos.

  4. Antibacterial activity of plasma from crocodile (Crocodylus siamensis) against pathogenic bacteria

    PubMed Central

    2012-01-01

    Background The Siamese crocodile (Crocodylus siamensis) is a critically endangered species of freshwater crocodiles. Crocodilians live with opportunistic bacterial infection but normally suffer no adverse effects. They are not totally immune to microbial infection, but their resistance thereto is remarkably effective. In this study, crude and purified plasma extracted from the Siamese crocodile were examined for antibacterial activity against clinically isolated, human pathogenic bacterial strains and the related reference strains. Methods Crude plasma was prepared from whole blood of the Siamese crocodile by differential sedimentation. The crude plasma was examined for antibacterial activity by the liquid growth inhibition assay. The scanning electron microscopy was performed to confirm the effect of crude crocodile plasma on the cells of Salmonella typhi ATCC 11778. Effect of crude crocodile plasma on cell viability was tested by MTT assay. In addition, the plasma was purified by anion exchange column chromatography with DEAE-Toyopearl 650 M and the purified plasma was tested for antibacterial activity. Results Crude plasma was prepared from whole blood of the Siamese crocodile and exhibited substantial antibacterial activities of more than 40% growth inhibition against the six reference strains of Staphylococcus aureus, Salmonella typhi, Escherichia coli, Vibrio cholerae, Pseudomonas aeruginosa, and Staphylococcus epidermidis, and the four clinical isolates of Staphylococcus epidermidis, Pseudomonas aeruginosa, Salmonella typhi, and Vibrio cholerae. Especially, more than 80% growth inhibition was found in the reference strains of Salmonella typhi, Vibrio cholerae, and Staphylococcus epidermidis and in the clinical isolates of Salmonella typhi and Vibrio cholerae. The effect of the crude plasma on bacterial cells of Salmonella typhi, a certain antibacterial material probably penetrates progressively into the cytoplasmic space, perturbing and damaging bacterial

  5. Kupffer cell structure in the juvenile Nile crocodile, Crocodylus niloticus.

    PubMed

    van Wilpe, Erna; Groenewald, Hermanus Bernardus

    2014-01-01

    The morphology of Kupffer cells was examined in the liver of the juvenile Nile crocodile using light microscopy and transmission electron microscopy. Pleomorphic Kupffer cells were located in the sinusoids, in the space of Disse, in the hepatic parenchyma and often connected adjacent sinusoids. The cell surfaces were irregular due to the presence of filopodia and lamelliapodia with phagocytosis of white blood cells, red blood cells and thrombocytes being evident. The cells were in close contact with endothelial cells and pit cells in the sinusoidal lumen and with stellate cells in the space of Disse. The cytoplasm contained large phagosomes comprising a combination of ceroid pigment, melanosomes and siderosomes. The nuclei were often indented and eccentrically placed due to the presence of the phagosomes. Conspicuous clusters of membrane-bound tubular organelles with a filamentous or crystalline interior were observed in the cytoplasm. The clusters were sometimes separated into smaller groups around phagosomes. A clear zone existed between the limiting membrane and the interior of these tubular organelles with the electron-dense interior profiles being, respectively, circular, angular or divided. The tubular organelles have not previously been described in Kupffer cells and possibly represent lysosomes with specialized functions. Mitochondria, microtubules, Golgi profiles, granular and smooth endoplasmic reticulum, and a few cytoplasmic lipid droplets were also present. The presence of the tubular organelles and the occurrence of the Kupffer cells in different locations in the liver of the juvenile Nile crocodile are indicative of particularly active and mobile cells.

  6. Non-invasive assessment of adrenocortical function in captive Nile crocodiles (Crocodylus niloticus).

    PubMed

    Ganswindt, Stefanie B; Myburgh, Jan G; Cameron, Elissa Z; Ganswindt, Andre

    2014-11-01

    The occurrence of stress-inducing factors in captive crocodilians is a concern, since chronic stress can negatively affect animal health and reproduction, and hence production. Monitoring stress in wild crocodiles could also be beneficial for assessing the state of health in populations which are potentially threatened by environmental pollution. In both cases, a non-invasive approach to assess adrenocortical function as a measure of stress would be preferable, as animals are not disturbed during sample collection, and therefore sampling is feedback-free. So far, however, such a non-invasive method has not been established for any crocodilian species. As an initial step, we therefore examined the suitability of two enzyme-immunoassays, detecting faecal glucocorticoid metabolites (FGMs) with a 11β,21-diol-20-one and 5β-3α-ol-11-one structure, respectively, for monitoring stress-related physiological responses in captive Nile crocodiles (Crocodylus niloticus). An adrenocorticotropic hormone (ACTH) challenge was performed on 10 sub-adult crocodiles, resulting in an overall increase in serum corticosterone levels of 272% above the pre-injection levels 5h post-injection. Saline-treated control animals (n=8) showed an overall increase of 156% in serum corticosterone levels 5h post-administration. Faecal samples pre- and post-injection could be obtained from three of the six individually housed crocodiles, resulting in FGM concentrations 136-380% above pre-injection levels, always detected in the first sample collected post-treatment (7-15 days post-injection). FGM concentrations seem comparatively stable at ambient temperatures for up to 72 h post-defaecation. In conclusion, non-invasive hormone monitoring can be used for assessing adrenocortical function in captive Nile crocodiles based on FGM analysis.

  7. Scaling of standard metabolic rate in estuarine crocodiles Crocodylus porosus.

    PubMed

    Seymour, Roger S; Gienger, C M; Brien, Matthew L; Tracy, Christopher R; Charlie Manolis, S; Webb, Grahame J W; Christian, Keith A

    2013-05-01

    Standard metabolic rate (SMR, ml O2 min(-1)) of captive Crocodylus porosus at 30 °C scales with body mass (kg) according to the equation, SMR = 1.01 M(0.829), in animals ranging in body mass of 3.3 orders of magnitude (0.19-389 kg). The exponent is significantly higher than 0.75, so does not conform to quarter-power scaling theory, but rather is likely an emergent property with no single explanation. SMR at 1 kg body mass is similar to the literature for C. porosus and for alligators. The high exponent is not related to feeding, growth, or obesity of captive animals. The log-transformed data appear slightly curved, mainly because SMR is somewhat low in many of the largest animals (291-389 kg). A 3-parameter model is scarcely different from the linear one, but reveals a declining exponent between 0.862 and 0.798. A non-linear model on arithmetic axes overestimates SMR in 70% of the smallest animals and does not satisfactorily represent the data.

  8. An investigation of antioxidant and anti-inflammatory activities from blood components of Crocodile (Crocodylus siamensis).

    PubMed

    Phosri, Santi; Mahakunakorn, Pramote; Lueangsakulthai, Jiraporn; Jangpromma, Nisachon; Swatsitang, Prasan; Daduang, Sakda; Dhiravisit, Apisak; Thammasirirak, Sompong

    2014-10-01

    Antioxidant and anti-inflammatory activities were found from Crocodylus siamensis (C. siamensis) blood. The 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging, nitric oxide scavenging, hydroxyl radical scavenging and linoleic peroxidation assays were used to investigate the antioxidant activities of the crocodile blood. Results show that crocodile blood components had antioxidant activity, especially hemoglobin (40.58 % nitric oxide radical inhibition), crude leukocyte extract (78 % linoleic peroxidation inhibition) and plasma (57.27 % hydroxyl radical inhibition). Additionally, the anti-inflammatory activity of the crocodile blood was studied using murine macrophage (RAW 264.7) as a model. The results show that hemoglobin, crude leukocyte extract and plasma were not toxic to RAW 264.7 cells. Also they showed anti-inflammatory activity by reduced nitric oxide (NO) and interleukin 6 (IL-6) productions from lipopolysaccharide (LPS)-stimulated cells. The NO inhibition percentages of hemoglobin, crude leukocyte extract and plasma were 31.9, 48.24 and 44.27 %, respectively. However, only crude leukocyte extract could inhibit IL-6 production. So, the results of this research directly indicate that hemoglobin, crude leukocyte extract and plasma of C. siamensis blood provide both antioxidant and anti-inflammatory activities, which could be used as a supplementary agent in pharmaceutical products.

  9. Metals and metallothioneins in Morelet's crocodile (Crocodylus moreletii) from a transboundary river between Mexico and Belize.

    PubMed

    Buenfil-Rojas, A M; Álvarez-Legorreta, T; Cedeño-Vázquez, J R

    2015-02-01

    The aim of this study was to determine concentrations of heavy metals (cadmium [Cd] and mercury [Hg]) and metallothioneins (MTs) in blood plasma and caudal scutes of Morelet's crocodile (Crocodylus moreletii) from Rio Hondo, a river and natural border between Mexico and Belize. Three transects of the river (approximately 20 km each) were surveyed in September 2012 and April 2013, and samples were collected from 24 crocodiles from these areas. In blood plasma, Cd (7.6 ± 9.6 ng/ml) was detected in 69 % of samples (n = 9); Hg (12.2 ± 9.2 ng/ml) was detected in 46 % of samples (n = 6); and MTs (10,900 ± 9,400 ng/ml) were detected in 92 % of samples (n = 12). In caudal scutes samples, Cd (31.7 ± 39.4 ng/g) was detected in 84 % of samples (n = 12) and Hg (374.1 ± 429.4 ng/g) in 83 % of samples (n = 20). No MTs were detected in caudal scutes. Hg concentrations in scutes from the Rio Hondo were 2- to 5-fold greater than those previously reported in scutes from other localities in northern Belize. In blood plasma, a significant positive relationship between Hg and body size was observed. Mean concentrations of Cd and MTs in size classes suggest that MTs may be related to Cd exposure. This is the first report of MT presence in crocodile blood.

  10. Melatonin rhythms in the Australian freshwater crocodile (Crocodylus johnstoni): a reptile lacking a pineal complex?

    PubMed

    Firth, Bruce T; Christian, Keith A; Belan, Ingrid; Kennaway, David J

    2010-01-01

    The vertebrate pineal gland is the primary source of melatonin, the rhythmic secretion of which is influenced by environmental light and temperature, thereby providing animals with information about seasonally changing photoperiod and thermoperiod. Although pineal glands are present in the majority of vertebrate species, a discrete organ is reported to be absent in the Crocodilia. However, if the melatonin rhythm is crucial to the survival of the organism, it would be expected that the rhythm would be present in crocodiles. In the present study, we measured blood plasma melatonin over a 30-h period in aestivating Australian freshwater crocodiles (Crocodylus johnstoni) in their natural habitat at the end of the dry season (November) and found no discernible melatonin rhythm. However, another group of captive-reared C. johnstoni, maintained under natural light and temperature cycles and sampled in the early dry season (June) showed a clear melatonin rhythm. These results suggest that there is either an extrapineal source of melatonin in this crocodile species or that there is melatonin producing tissue elsewhere which heretofore has not been discovered. Further studies are needed to determine why the melatonin rhythm is intermittently expressed and whether this may be related to seasonal changes in the expression of the rhythm linked to tropical environments.

  11. Satellite tracking reveals long distance coastal travel and homing by translocated estuarine crocodiles, Crocodylus porosus.

    PubMed

    Read, Mark A; Grigg, Gordon C; Irwin, Steve R; Shanahan, Danielle; Franklin, Craig E

    2007-09-26

    Crocodilians have a wide distribution, often in remote areas, are cryptic, secretive and are easily disturbed by human presence. Their capacity for large scale movements is poorly known. Here, we report the first study of post-release movement patterns in translocated adult crocodiles, and the first application of satellite telemetry to a crocodilian. Three large male Crocodylus porosus (3.1-4.5 m) were captured in northern Australia and translocated by helicopter for 56, 99 and 411 km of coastline, the last across Cape York Peninsula from the west coast to the east coast. All crocodiles spent time around their release site before returning rapidly and apparently purposefully to their capture locations. The animal that circumnavigated Cape York Peninsula to return to its capture site, travelled more than 400 km in 20 days, which is the longest homeward travel yet reported for a crocodilian. Such impressive homing ability is significant because translocation has sometimes been used to manage potentially dangerous C. porosus close to human settlement. It is clear that large male estuarine crocodiles can exhibit strong site fidelity, have remarkable navigational skills, and may move long distances following a coastline. These long journeys included impressive daily movements of 10-30 km, often consecutively.

  12. Activity, abundance, distribution and expression of Na+/K+-ATPase in the salt glands of Crocodylus porosus following chronic saltwater acclimation.

    PubMed

    Cramp, Rebecca L; Hudson, Nicholas J; Franklin, Craig E

    2010-04-01

    Saltwater crocodiles, Crocodylus porosus, possess lingual salt glands which function to remove excess Na(+) and Cl(-) accumulated as a consequence of living in salt water. Little is known about the nature of ion transport systems in C. porosus salt glands and how these systems respond to an osmotic challenge. In the present study, we examined the distribution and regulation of the Na(+)/K(+)-ATPase (NKA) pump, specifically the alpha-(catalytic) subunit in the salt glands of C. porosus chronically acclimated (6 months) to freshwater (FW) or 70% seawater (SW). We hypothesised that in the SW-acclimated C. porosus there would be an up-regulation of the abundance, activity and gene expression of the NKA transporter. NKA was immunolocalised to the lateral and basal membrane of secretory cells. As predicted, the NKA alpha-subunit was 2-fold more abundant in SW-acclimated C. porosus salt glands. NKA gene expression was also elevated in the salt glands of SW- vs FW-acclimated crocodiles. There was no increase in the specific activity of NKA in SW-acclimated animals and the in vitro rate of oxygen consumption by salt gland slices from SW-acclimated animals was not significantly different from that of FW-acclimated animals. The proportion of tissue oxygen consumption rate attributable to NKA activity was not different between SW- and FW-acclimated animals (approximately 50%). These data suggest that either chronic SW acclimation does not affect NKA in crocodile salt glands in the same manner as seen in other models or crocodiles possess the capacity to moderate NKA activity following prolonged exposure to SW.

  13. The occurrence of Trichinella zimbabwensis in naturally infected wild crocodiles (Crocodylus niloticus) from the Kruger National Park, South Africa.

    PubMed

    La Grange, L J; Govender, D; Mukaratirwa, S

    2013-03-01

    Trichinella zimbabwensis has been found naturally infecting crocodiles (Crocodylus niloticus) in Zimbabwe, Mozambique, Ethiopia and South Africa, as well as monitor lizards (Varanus niloticus) in Zimbabwe. The reports on natural infections were mostly accidental rather than structured surveys and involved very few animals. Previous surveillance studies in South Africa reported a 38.5% prevalence of T. zimbabwensis among wild crocodiles tested from the Mpumalanga province and Kruger National Park (KNP). No studies have been conducted to date on the geographical distribution and occurrence of T. zimbabwensis in wild crocodiles and varans in countries in southern Africa. Recent outbreaks of pansteatitis in crocodile populations of the KNP, South Africa, provided an opportunity to conduct a more structured survey aimed at elucidating the occurrence and distribution of T. zimbabwensis in culled wild crocodile populations within the KNP. Results from this study showed that T. zimbabwensis occurred in 10 out of 12 culled crocodiles form the KNP. The results also showed that the natural distribution of T. zimbabwensis in crocodiles includes all the major river systems in the KNP. The predilection sites of larvae in muscles followed a different pattern in naturally infected crocodiles compared to observations in experimentally infected mammalian hosts.

  14. Perfluorinated alkyl acids in the plasma of South African crocodiles (Crocodylus niloticus).

    PubMed

    Christie, Ian; Reiner, Jessica L; Bowden, John A; Botha, Hannes; Cantu, Theresa M; Govender, Danny; Guillette, Matthew P; Lowers, Russell H; Luus-Powell, Wilmien J; Pienaar, Danie; Smit, Willem J; Guillette, Louis J

    2016-07-01

    Perfluorinated alkyl acids (PFAAs) are environmental contaminants that have been used in many products for over 50 years. Interest and concern has grown since 2000 on the widespread presence of PFAAs, when it was discovered that PFAAs were present in wildlife samples around the northern hemisphere. Since then, several studies have reported PFAAs in wildlife from many locations, including the remote regions of Antarctica and the Arctic. Although there are a multitude of studies, few have reported PFAA concentrations in reptiles and wildlife in the Southern Hemisphere. This study investigated the presence of PFAAs in the plasma of Nile crocodiles (Crocodylus niloticus) from South Africa. Crocodiles were captured from five sites in and around the Kruger National Park, South Africa, and plasma samples examined for PFAAs. Perfluorooctane sulfonate (PFOS) was the most frequent PFAA detected; with median values of 13.5 ng/g wet mass in crocodiles. In addition to PFOS, long chain perfluorinated carboxylic acids were also detected. Correlations between total length and PFAA load were investigated, as were differences in PFAA accumulation between sexes. No correlations were seen between crocodile size, nor were there sex-related differences. Spatial differences were examined and significant differences were observed in samples collected from the different sites (p < 0.05). Flag Boshielo Dam had the highest PFOS measurements, with a median concentration of 50.3 ng/g wet mass, when compared to the other sites (median concentrations at other sites below 14.0 ng/g wet mass). This suggests a point source of PFOS in this area.

  15. Nesting phenology and clutch characteristics of captive Siamese crocodiles (Crocodylus siamensis) in Cambodia.

    PubMed

    Platt, Steven G; Monyrath, Vuthy; Sovannara, Heng; Kheng, Long; Rainwater, Thomas R

    2012-01-01

    The Siamese crocodile (Crocodylus siamensis) is considered one of the least studied and most critically endangered crocodilians in the world. Although few wild populations remain, more than 700,000 C. siamensis are held on commercial crocodile farms in Southeast Asia. Despite conservation concerns, many aspects of C. siamensis life history remain poorly known, particularly with regards to its reproductive biology. We studied nesting phenology, clutch characteristics, and other aspects of C. siamensis reproductive biology on crocodile farms in Cambodia during 2000 and 2001. Oviposition among captive crocodiles began in February and continued into early June. The mean (±1 SD) oviposition date based on pooled data from 2000 and 2001 was 5 April ± 24 days. Mean oviposition date differed significantly between 2000 and 2001, possibly as a result of annual variability among nesting cues. The mean incubation period was 72 ± 3 days and eggs hatched from 5 May to 18 August. Mean clutch size (25.0 ± 8.8 eggs; n = 183) differed significantly between years, possibly resulting from the >2.5-fold increase in sample size during 2001. There was no correlation between clutch size and oviposition date during either 2000 or 2001. A single female produced two clutches during 2001, complimenting previous reports of double-clutching among C. siamensis. The mean length and width of 515 eggs were 78.2 ± 4.9 and 48.1 ± 2.5 mm, respectively; mean egg mass was 90.8 ± 16.5 g (n = 471). One unpipped egg contained a set of twins.

  16. Redistribution of air within the lungs may potentiate "fright" bradycardia in submerged crocodiles (Crocodylus porosus).

    PubMed

    Wright, J C; Grigg, G C; Franklin, C E

    1992-05-01

    1. Voluntary undisturbed dives by Crocodylus porosus were short in duration (3.08 +/- 1.87 min, mean +/- SD) and accompanied by a small but significant bradycardia (14.3 +/- 5.9% drop). 2. When crocodiles were disturbed underwater there was a rapid onset of "fright" bradycardia, to 65 +/- 6.0% of surface heart rates and dive durations were prolonged to 19.6 +/- 1.8 min. 3. The development of "fright" bradycardia was not accompanied by any increase in intratracheal pressure or expulsion of lung gas. However, sustained contraction of the abdomen and expansion of the thorax revealed a redistribution of air anteriorly within the lungs. 4. We propose that the redistribution of air within the lungs may generate an afferent signal which potentiates the initiation of a severe, dive-prolonging bradycardia.

  17. Nesting of Morelet's crocodile, Crocodylus moreletii (Dumeril and Bibron), in Los Tuxtlas, Mexico.

    PubMed

    Villegas, A; Mendoza, G D; Arcos-García, J L; Reynoso, V H

    2017-03-16

    We evaluated the nesting by Crocodylus moreletii in Lago de Catemaco, Veracruz, southeastern, Mexico. During the nesting and hatching seasons, we searched for nests along the northern margins of the lake and small associated streams. We investigated egg mortality by weekly monitoring each of the nests found, recording sign of predation (tracks and holes dug into the nest) and the effect of water level fluctuations. We not found differences to nest between inland or flooded zones. However, we found that egg size varied among nests. In nests built inland, predation was the major cause of egg mortality whereas flooding resulted in more deaths of eggs in the flooding zone. Flooding killed 25% of eggs monitored in this study. We suggest that to increase nest success in the Morelet's crocodile it is necessary to promote conservation of nesting areas around the lake, recently occupied by urban or tourist developments.

  18. Sudden death of a Siamese crocodile (Crocodylus siamensis) due to systemic aspergillosis

    PubMed Central

    KIM, Kyoo-Tae; LEE, Seung-Hun; KWAK, Dongmi

    2016-01-01

    A 4-year-old female Siamese crocodile (Crocodylus siamensis) housed at a zoo died without any prior clinical signs. During necropsy, numerous scattered, well-demarcated, yellowish-white, firm nodules were observed throughout the liver and lungs. Microscopic examination with periodic acid-Schiff staining revealed granulomatous inflammation in the liver and lungs. Liver granulomas were characterized by the presence of a connective tissue barrier and hyphae, and the centers of the granulomas showed signs of necrosis. Lung samples showed characteristics similar to those observed in the liver samples. The fungus was identified as Aspergillus fumigatus based on its appearance on Sabouraud dextrose agar, microscopic examination with lactophenol cotton blue staining and genetic sequencing. Therefore, zoo veterinarians should pay close attention to fungal infections in captive animals. PMID:27476559

  19. Organochlorine contaminants in complete clutches of Morelet's crocodile (Crocodylus moreletii) eggs from Belize.

    PubMed

    Wu, Ted H; Cañas, Jaclyn E; Rainwater, Thomas R; Platt, Steven G; McMurry, Scott T; Anderson, Todd A

    2006-11-01

    Seven complete clutches of Morelet's crocodile (Crocodylus moreletii) eggs were collected in northern Belize and examined for organochlorine (OC) pesticide residues. The primary OC detected, p,p-DDE, was found in every egg analyzed (n=175). Other OCs detected included p,p-DDT, p,p-DDD, methoxychlor, aldrin, and endosulfan I. Concentrations of individual OCs ranged from 4 ppb (ng chemical/g egg wet weight) to greater than 500 ppb. A statistical evaluation of p,p-DDE levels in three complete clutches was used to derive the minimum number of eggs needed from a clutch to precisely determine the mean p,p-DDE concentration representative of that clutch. Sample sizes of 8 (80% confidence level) and 11 (90% confidence level) were determined to yield an accurate estimate of contaminant levels in a full clutch of eggs. The statistically recommended sample size of 11 eggs (at 90% confidence level) was successfully tested on the four additional clutches.

  20. Some helminth parasites from Morelet's crocodile, Crocodylus moreletii, from Yucatan, Mexico.

    PubMed

    Moravec, F

    2001-01-01

    An examination of three specimens of the Morelet's crocodile, Crocodylus moreletii Duméril et Bibron, from the Lagoon of Celestún, Yucatan, Mexico revealed the presence of the following eight helminth species: Acanthostomum americanum (Pérez Vigueras, 1956), Pelaezia loossi (Pérez Vigueras, 1956), Telorchis sp. juv., Pseudoneodiplostomum groschafti sp. n. (all trematodes), Dujardinascaris helicina (Molin, 1860), Contracaecum sp. Type 2 larvae, Micropleura sp. and Paratrichosoma recurvum (Solger, 1877) (all nematodes). Pseudoneodiplostomum groschafti sp. n. is established by indication based on the description of specimens from Crocodylus rhombifer from Cuba, given by Groschaft and Barus (1970). Acanthostomum acuti Caballero et Brennes, 1959 is considered a synonym of A. americanum. A. americanum and D. helicina are recorded for the first time from Mexico and Micropleura sp. is the first American representative of the genus recorded outside South America. Findings of A. americanum, Telorchis sp., P. groschafti, D. helicina and Micropleura sp. in C. moreletii represent new host records. Some observations on the early development of D. helicina are provided. All species, except for P. recurvum, are briefly described and illustrated and some problems concerning their morphology, taxonomy and geographical distribution are discussed.

  1. Hematologic and plasma biochemical reference intervals for Morelet's crocodiles (Crocodylus moreletii) in the northern wetlands of Campeche, Mexico.

    PubMed

    Padilla, Sergio E; Weber, Manuel; Jacobson, Elliott R

    2011-07-01

    Health surveys and hematologic and plasma biochemical analyses were conducted in 52 free-ranging and 51 captive Morelet's crocodiles (Crocodylus moreletii) in Campeche, Mexico, March-September 2007. Blood samples from 92 crocodiles (45 free-ranging and 47 captive) were collected for hematologic and plasma biochemical analyses. Average values of erythrocytes of free-ranging crocodiles were 1,046,166 cells/μl, and total white cells were 1.03 × 10(4) cells/μl. Captive crocodiles had erythrocyte and leukocyte values of 1,100,416 cells/μl and 8.51 × 10(3) cells/μl, respectively. There were no significant differences in values of erythrocytes or in hematocrit between free-ranging and captive crocodiles, or between sexes, or among size classes. Counts of leukocytes in free-ranging crocodiles were significantly higher than in captive individuals. The mean values of plasma analytes were 69.55 mg/l (glucose), 250.14 mg/l (cholesterol), 3.04 mg/l (uric acid), 2.70 mg/l (creatinine), and 20.20 IU/l (alanine aminotransferase). There were significant differences in cholesterol between free-ranging and captive crocodiles and between sexes.

  2. Exercise training enhances aerobic capacity in juvenile estuarine crocodiles (Crocodylus porosus).

    PubMed

    Owerkowicz, Tomasz; Baudinette, Russell V

    2008-06-01

    Aerobic capacity (VO2max) of endothermic vertebrates is known to increase with exercise training, but this effect has not been found to-date in non-avian reptiles. We exercised juvenile estuarine crocodiles (Crocodylus porosus) to walk at 0.75-0.88 km/h on a treadmill for up to 20 min a day over 16 weeks, and compared their aerobic performance with that of unexercised crocodiles. In the exercised group, VO2max increased from 6.9 to 8.5 mLO2/kg/min (+28%), and locomotor endurance increased from 3.8 to 6.9 min (+82%). Neither VO2max nor endurance changed significantly in the sedentary group. This finding extends the exercise training effect onto another vertebrate clade, and demonstrates that ectothermic amniotes are capable of elevating their aerobic capacity in response to exercise training. We propose that differences in cardiopulmonary structure and function in non-avian reptiles may be responsible for the absence (in squamates) or presence (in crocodilians) of a strong training effect on aerobic capacity.

  3. Metals in the caudal scutes of Morelet's crocodile (Crocodylus moreletii) from the southern Gulf of Mexico.

    PubMed

    Trillanes, C E; Pérez-Jiménez, J C; Rosíles-Martínez, R; González-Jáuregui, M

    2014-10-01

    Caudal scutes were collected from 92 Morelet's crocodiles (Crocodylus moreletii) between May and August 2012, in three Wildlife Management and Use Units (UMAs, from its name in Spanish) and three wild sites in Campeche, Mexico. The UMAs are intensive, with an ex situ approach to manage crocodiles in captivity. The concentrations of arsenic, mercury, lead, nickel, cadmium and chromium were analyzed in each sample. As and Pb were detected in all samples, Hg in 86 and Ni in 74. The metal concentrations estimated were higher than most of the concentrations reported for skin, tail tip and caudal scutes in other crocodilians around the world. The concentration of As, Pb and Ni was significantly greater in the free-ranging groups than in the captive groups in UMAs (p < 0.05). Negative linear relationship was estimated between the snout-vent length and the concentration of Pb (in five groups) and Ni (in three groups). In this region C. moreletii is exposed to metals contamination and more studies are necessary to establish if represents a risk to their populations.

  4. Evaluating the effect of salinity on a simulated American Crocodile (Crocodylus acutus) population with applications to conservation and Everglades restoration

    USGS Publications Warehouse

    Richards, Paul M.; Mooij, Wolf M.; DeAngelis, Donald L.

    2004-01-01

    Everglades restoration will alter the hydrology of South Florida, affecting both water depth and salinity levels in the southern fringes of the Everglades, the habitat of the endangered American crocodile (Crocodylus acutus). A key question is what the effects of these hydrologic changes will be on the crocodile population. Reliable predictions of the viability of endangered species under a variety of management scenarios are of vital importance in conservation ecology. Juvenile American crocodiles are thought to be sensitive to high salinity levels, suffering reduced mass, and potentially reduced survivorship and recruitment. This could negatively impact the population recovery. We addressed the management issue of how the crocodile population will respond to alterations in hydrology with a spatially explicit individual-based model. The model is designed to relate water levels, salinities, and dominant vegetation to crocodile distribution, abundance, population growth, individual growth, survival, nesting effort, and nesting success. Our analysis shows that Everglades restoration, through its effects on water flow to estuaries, may benefit crocodile populations if increased freshwater flow reduces the chance that regional salinity levels exceed levels where small individuals lose mass. In addition, we conclude that conservation priority should be placed on reducing anthropogenic sources of mortality on large individuals, such as road mortality. Finally, research should focus on estimates of annual survivorship for large individuals.

  5. Population assessment of the American crocodile, Crocodylus acutus (Crocodilia: Crocodylidae) on the Pacific coast of Costa Rica.

    PubMed

    Mauger, Laurie A; Velez, Elizabeth; Cherkiss, Michael S; Brien, Matthew L; Boston, Michael; Mazzotti, Frank J; Spotila, James R

    2012-12-01

    The American crocodile, Crocodylus acutus, is widely distributed in the American neotropics. It is endangered throughout most of its range and is listed as vulnerable by the International Union for the Conservation of Natural Fauna and Flora (IUCN) and on Appendix I of the Convention for the International Trade in Endangered Species of Wild Flora and Fauna (CITES). Despite this listing, there are few published reports on population status throughout most of its range. We investigated the status of the C. acutus, at several locations along the Pacific coast of Costa Rica. We carried out spotlight and nesting surveys from 2007-2009 along the Costa Rican Pacific coast in four distinct areas, coastal areas of Las Baulas (N=40) and Santa Rosa (N=9) National Parks and the Osa Conservation Area (N=13), and upriver in Palo Verde National Park (N=11). We recorded crocodile locations and standard environmental data at each observation. Encounter rates, population structure, distribution within each area and data on successful nesting (presence of hatchlings, nests, etc) were determined. We attempted to capture all crocodiles to record standard morphometrics. A total of 586 crocodiles were observed along 185.8km of survey route. The majority of animals encountered (54.9%) were either hatchlings (<0.5m) or juveniles (0.5-1.25m). The average non-hatchling encounter rate per survey for the Pacific coast was 3.1 crocodiles/km, with individual encounter rates ranging from 1.2 crocodiles/km to 4.3 crocodiles/ km in Las Baulas National Park and the Osa Conservation Area respectively. Distribution of size classes within the individual locations did not differ with the exception of Santa Rosa and Las Baulas National Parks, where hatchlings were found in water with lower salinities. These were the first systematic surveys in several of the areas studied and additional work is needed to further characterize the American crocodile population in Costa Rica.

  6. Developmental alterations and endocrine-disruptive responses in farmed Nile crocodiles (Crocodylus niloticus) exposed to contaminants from the Crocodile River, South Africa.

    PubMed

    Arukwe, Augustine; Myburgh, Jan; Langberg, Håkon A; Adeogun, Aina O; Braa, Idunn Godal; Moeder, Monika; Schlenk, Daniel; Crago, Jordan Paul; Regoli, Francesco; Botha, Christo

    2016-04-01

    In the present study, the developmental (including fertility) and endocrine-disruptive effects in relation to chemical burden in male and female Nile crocodiles (Crocodylus niloticus), from a commercial crocodile farm in the Brits district, South Africa, exposed to various anthropogenic aquatic contaminants from the natural environment was investigated. Hepatic transcript levels for vitellogenin (Vtg), zona pellucida (ZP) and ERα (also in gonads) were analyzed using real-time PCR. Plasma estradiol-17β (E2), testosterone (T) and 11-ketotestosterone (11-KT) were analyzed using enzyme immunoassay. Gonadal aromatase and hepatic testosterone metabolism (6β-hydroxylase (6β-OHase)) were analyzed using biochemical methods. Overall, there is high and abnormal number (%) of infertile and banded eggs during the studied reproductive seasons, showing up to 57 and 34% of infertile eggs in the 2009/2010 and 2013/2014 seasons, respectively. In addition, the percentage of banded eggs ranged between 10 and 19% during the period of 2009-2014 seasons. While hepatic ERα, Vtg, ZP mRNA and testosterone 6β-OHase, were equally expressed in female and male crocodiles, gonadal ERα mRNA and aromatase activity were significantly higher in females compared to male crocodiles. On the other hand, plasma T and 11-KT levels were significantly higher in males, compared to female crocodiles. Principal component analysis (PCA) produced significant grouping that revealed correlative relationships between reproductive/endocrine-disruptive variables and liver contaminant burden, that further relates to measured contaminants in the natural environment. The overall results suggest that these captive pre-slaughter farm crocodiles exhibited responses to anthropogenic aquatic contaminants with potentially relevant consequences on key reproductive and endocrine pathways and these responses may be established as relevant species endocrine disruptor biomarkers of exposure and effects in this threatened

  7. Age, fertility and reproductive behavior in cuban crocodiles, Crocodylus rhombifer, at the Smithsonian's National Zoological Park.

    PubMed

    Augustine, Lauren; Watkins, Barbara

    2015-01-01

    The Smithsonian's National Zoological Park (NZP) has a long history with Cuban crocodiles, Crocodylus rhombifer, beginning in 1900's when the first animals arrived at the NZP. Today, the Zoo has two breeding groups of C. rhombifer and has observed and analyzed reproductive behavior and fertility rates over the last three years. Fertility rates were determined initially by observing the formation of an opaque band that forms on the shell of a fertile egg, called banding. The fertility rates by banding were later compared to the observation made after opening the eggs to verify fertility. In addition to tracking fertility, nesting and agonistic behavior were also observed. Several notable observations were documented over the same period. These included a male predating a nesting female's eggs, increased aggression between two females housed together, the continued development of a partially banded egg, and the discovery of 19 additional egg shells post oviposition by both females in the enclosure. Here we discuss the nest phenology, fertility and behavior of the five exhibited C. rhombifer at the Smithsonian's National Zoological Park over a 3-year period. Zoo Biol. 34:278-284, 2015. © 2015 Wiley Periodicals Inc.

  8. Bioactive compounds from crocodile (Crocodylus siamensis) white blood cells induced apoptotic cell death in hela cells.

    PubMed

    Patathananone, Supawadee; Thammasirirak, Sompong; Daduang, Jureerut; Chung, Jing Gung; Temsiripong, Yosapong; Daduang, Sakda

    2016-08-01

    Crocodile (Crocodylus siamensis) white blood cell extracts (WBCex) were examined for anticancer activity in HeLa cell lines using the MTT assay. The percentage viability of HeLa cells significantly deceased after treatment with WBCex in a dose- and time-dependent manner. The IC50 dose was suggested to be approximately 225 μg/mL protein. Apoptotic cell death occurred in a time-dependent manner based on investigation by flow cytometry using annexin V-FITC and PI staining. DAPI nucleic acid staining indicated increased chromatin condensation. Caspase-3, -8 and -9 activities also increased, suggesting the induction of the caspase-dependent apoptotic pathway. Furthermore, the mitochondrial membrane potential (ΔΨm ) of HeLa cells was lost as a result of increasing levels of Bax and reduced levels of Bcl-2, Bcl-XL, Bcl-Xs, and XIAP. The decreased ΔΨm led to the release of cytochrome c and the activation of caspase-9 and -3. Apoptosis-inducing factor translocated into the nuclei, and endonuclease G (Endo G) was released from the mitochondria. These results suggest that anticancer agents in WBCex can induce apoptosis in HeLa cells via both caspase-dependent and -independent pathways. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 986-997, 2016.

  9. Conservation genetics of American crocodile, Crocodylus acutus, populations in Pacific Costa Rica

    USGS Publications Warehouse

    Mauger, Laurie A.; Velez, Elizabeth; Cherkiss, Michael S.; Brien, Matthew L.; Mazzotti, Frank J.; Spotila, James R.

    2017-01-01

    Maintaining genetic diversity is crucial for the survival and management of threatened and endangered species. In this study, we analyzed genetic diversity and population genetic structure at neutral loci in American crocodiles, Crocodylus acutus, from several areas (Parque Nacional Marino Las Baulas, Parque Nacional Santa Rosa, Parque Nacional Palo Verde, Rio Tarcoles, and Osa Conservation Area) in Pacific Costa Rica. We genotyped 184 individuals at nine microsatellite loci to describe the genetic diversity and conservation genetics between and among populations. No population was at Hardy-Weinberg Equilibrium (HWE) over all loci tested and a small to moderate amount of inbreeding was present. Populations along the Pacific coast had an average heterozygosity of 0.572 across all loci. All populations were significantly differentiated from each other with both FST and RST measures of population differentiation with a greater degree of molecular variance (81%) found within populations. Our results suggest C. acutus populations in Pacific Costa Rica were not panmictic with moderate levels of genetic diversity. An effective management plan that maintains the connectivity between clusters is critical to the success of C. acutus in Pacific Costa Rica.

  10. Comparison of the lipid properties of captive, healthy wild, and pansteatitis-affected wild Nile crocodiles (Crocodylus niloticus).

    PubMed

    Osthoff, Gernot; Hugo, Arno; Bouwman, Henk; Buss, Peter; Govender, Danny; Joubert, Chris C; Swarts, Jannie C

    2010-01-01

    The results presented describe and compare the fatty acid composition and melting properties of captive, healthy wild, and pansteatitis-affected wild crocodiles (Crocodylus niloticus). Differences in fatty acid composition between intramuscular and adipose fat is noted in captive crocodiles, and the latter differs from wild crocodiles as a result of different diets. Adipose fat of healthy wild crocodiles differs minimally from diseased ones, respectively with 37.3+/-2.6% vs. 43.2+/-2.3% monounsaturated fatty acids, and 43.2+/-2.9% in dead crocodiles, while polyunsaturated fatty acids decrease from 27.3+/-1.9% to as low as 21.9+/-3.6% respectively. Of the unsaturated fatty acids 18:2n-6 decreased from 6.5+/-2.6% in unaffected crocodiles to 3.5+/-0.6% in highly affected and 3.2+/-0.4% in dead crocodiles, and 22:5n-3 from 2.8+/-0.6% to 1.8+/-0.3% and 2.2+/-0.3% respectively. The melting properties as determined by differential scanning calorimetry show that extracted adipose fat is a small degree softer in pansteatitis-affected tissue, specifically in the temperature range 7-36 degrees C, and does not contribute to the hard texture noted for adipose fat tissue of pansteatitis-affected animals. A high moisture content of 51.0+/-19.7% of the fat tissue of pansteatitis-affected animals vs.17.1+/-8.0% of healthy ones, suggests that physiological changes due to interstitial inflammation may contribute to the hard texture.

  11. Molecular evidence for genetic distinctions between Chlamydiaceae detected in Siamese crocodiles (Crocodylus siamensis) and known Chlamydiaceae species.

    PubMed

    Sariya, Ladawan; Kladmanee, Kan; Bhusri, Benjaporn; Thaijongrak, Prawporn; Tonchiangsai, Kanittha; Chaichoun, Kridsada; Ratanakorn, Parntep

    2015-02-01

    Chlamydiosis, caused by Chlamydiaceae, is a zoonotic disease found in humans and several species of animals, including reptiles and amphibians. Although chlamydiosis in saltwater crocodiles has been previously reported in South Africa and Papua New Guinea, the reported strains have not been identified or confirmed. Therefore, the main aim of this study was to sequence and characterize Chamydiaceae isolated from Siamese crocodiles. Results showed the 16S ribosomal (r) RNA and the 16S/23S rRNA gene of the crocodile isolates were closely related to the genus Chlamydophila with matched identity greater than 98%. The phylogenetic tree constructed from the 16S/23S rRNA gene showed the crocodile cluster diverges far from Cp. caviae with a 100% bootstrap value. The tree based on the ompA gene loci distinguished the crocodile strains into genotypes I, II, and III. The present study is the first report on Chlamydophila detected in Siamese crocodiles that is genetically distinct from the known species of Chlamydiaceae.

  12. Parent-offspring communication in the Nile crocodile Crocodylus niloticus: do newborns' calls show an individual signature?

    NASA Astrophysics Data System (ADS)

    Vergne, Amélie L.; Avril, Alexis; Martin, Samuel; Mathevon, Nicolas

    2007-01-01

    Young Nile crocodiles Crocodylus niloticus start to produce calls inside the egg and carry on emitting sounds after hatching. These vocalizations elicit maternal care and influence the behaviour of other juveniles. In order to investigate the acoustic structure of these calls, focusing on a possible individual signature, we have performed acoustic analyses on 400 calls from ten young crocodiles during the first 4 days after hatching. Calls have a complex acoustic structure and are strongly frequency modulated. We assessed the differences between the calls of the individuals. We found a weak individual signature. An individual call-based recognition of young by the mother is thus unlikely. In other respects, the call acoustic structure changes from the first to the fourth day after hatching: fundamental frequency progressively decreases. These modifications might provide important information to the mother about her offspring—age and size—allowing her to customize her protective care to best suit the needs of each individual.

  13. Nest predation and maternal care in the Nile crocodile (Crocodylus niloticus) at Lake St Lucia, South Africa.

    PubMed

    Combrink, Xander; Warner, Jonathan K; Downs, Colleen T

    2016-12-01

    Information regarding nest predation, nest abandonment, and maternal care in the Nile crocodile (Crocodylus niloticus) is largely restricted to anecdotal observations, and has not been studied quantitatively. Consequently, we investigated their nesting biology using camera-traps over four years at Lake St Lucia, South Africa. We obtained 4305 photographs (daylight captures=90.1%, nocturnal=9.9%) of 19 nest-guarding females. Of 19 monitored nests, 37% were raided by predators (mean=12.1±6.2days subsequent to camera placement). All females returned to their nests following first predation, and on average returned three times between predator raids before nest abandonment. Water monitors (Varanus niloticus) and marsh mongoose (Atilax paludinosus) were the main egg predators. Nesting raids lasted 5.9±1.6days. Diurnally females were seldom on the nest, except during cool/cloudy weather or rain, preferring to guard from nearby shade. Females defended nests aggressively against non-human intruders. Five Nile crocodile females were observed liberating their hatchlings from nests. A detailed sequence of a mother excavating and transporting hatchlings revealed 13 excursions between nest and water over 32.5h. This, after months of continual nest attendance and defence, is illustrative of the high level of maternal care in Nile crocodiles. Camera-trapping is an effective, non-invasive method for further crocodile nesting behaviour research.

  14. Autoinduction, purification, and characterization of soluble α-globin chains of crocodile (Crocodylus siamensis) hemoglobin in Escherichia coli.

    PubMed

    Kabbua, Thai; Anwised, Preeyanan; Boonmee, Atcha; Subedi, Bishnu P; Pierce, Brad S; Thammasirirak, Sompong

    2014-11-01

    We have established a method to express soluble heme-bound recombinant crocodile (Crocodylus siamensis) α-globin chain holo-protein in bacteria (Escherichia coli) using an autoinduction system without addition of exogenous heme. This is the first time that heme-bound crocodile α-globin chains have been expressed in bacteria without in vitro heme reconstitution. The observed molecular mass of purified recombinant α-globin is consistent with that calculated from the primary amino acid sequence of native crocodile (C. siamensis) α-globin. Both the monomeric and the dimeric protein configuration formed by intermolecular disulfide bond could be purified as soluble protein. Spectroscopic characterization [UV-visible, circular dichroism (CD), and electron paramagnetic resonance (EPR)] of purified recombinant α-globin demonstrates nearly identical properties as reported for hemoglobin and myoglobin isolated from other organisms. For comparison, cyanide and nitric oxide binding of purified α-globin was also investigated. These results suggested that C. siamensis α-globin expressed in E. coli was folded correctly with proper incorporation of the heme cofactor. The expression method we now describe can facilitate production and isolation of individual globin chains in order to further study the mechanism and assembly of crocodile hemoglobin.

  15. Fine scale patterns of genetic partitioning in the rediscovered African crocodile, Crocodylus suchus (Saint-Hilaire 1807)

    PubMed Central

    Shirley, Matthew H.; Hekkala, Evon R.

    2016-01-01

    Landscape heterogeneity, phylogenetic history, and stochasticity all influence patterns of geneflow and connectivity in wild vertebrates. Fine-scale patterns of genetic partitioning may be particularly important for the sustainable management of widespread species in trade, such as crocodiles. We examined genetic variation within the rediscovered African crocodile, Crocodylus suchus, across its distribution in West and Central Africa. We genotyped 109 individuals at nine microsatellite loci from 16 sampling localities and used three Bayesian clustering techniques and an analysis of contemporary gene flow to identify population structure across the landscape. We identified up to eight genetic clusters that largely correspond to populations isolated in coastal wetland systems and across large distances. Crocodile population clusters from the interior were readily distinguished from coastal areas, which were further subdivided by distance and drainage basin. Migration analyses indicated contemporary migration only between closely positioned coastal populations. These findings indicate high levels of population structure throughout the range of C. suchus and we use our results to suggest a role for molecular tools in identifying crocodile conservation units for this species. Further research, including additional sampling throughout the Congo and Niger drainages, would clarify both the landscape connectivity and management of this species. PMID:27114867

  16. Identification and partial sequencing of a crocodile poxvirus associated with deeply penetrating skin lesions in farmed Nile crocodiles, Crocodylus niloticus.

    PubMed

    Huchzermeyer, F W; Wallace, D B; Putterill, J F; Gerdes, G H

    2009-09-01

    When large numbers of crocodile skins were downgraded because of the presence of small pin prick-like holes, collapsed epidermal cysts were found deep in the dermis of juvenile crocodiles while forming cysts were observed in hatchlings. Histopathology of these forming cysts showed the presence of intracytoplasmic inclusions in proliferating and ballooning epidermal cells. Pox virions were seen in electron microscope preparations made from the scabs of such early lesions. The partial sequencing of virus material from scrapings of these lesions and comparison of it with the published sequence of crocodile poxvirus showed the virus associated with the deep lesions to be closely related, but different. To differentiate between the two forms of crocodile pox infection it is suggested that the previously known form should be called "classical crocodile pox" and the newly discovered form "atypical crocodile pox". The application of strict hygiene measures brought about a decline in the percentage of downgraded skins.

  17. Critical Comment: On the morphology and taxonomy of Griphoibilharizia amoena Platt and Blair, 1991 (Schistosomatoidea), a dioecious digenetic trematode parasite of the freshwater crocodile, Crocodylus johnstoni, in Australia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Griphobilharzia amoena Platt and Blair, 1991, was originally described as a dioecious trematode parasitic in the circulatory system of the Australian freshwater crocodile, Crocodylus johnsoni, with the female completely enclosed in a gynecophoric chamber of the male and the 2 worms oriented anti-par...

  18. Distribution patterns and predilection muscles of Trichinella zimbabwensis larvae in experimentally infected Nile crocodiles (Crocodylus niloticus Laurenti).

    PubMed

    La Grange, Louis J; Mukaratirwa, Samson

    2014-02-21

    No controlled studies have been conducted to determine the predilection muscles of Trichinella zimbabwensis larvae in Nile crocodiles (Crocodylus niloticus) or the influence of infection intensity on the distribution of the larvae in crocodiles. The distribution of larvae in muscles of naturally infected Nile crocodiles and experimentally infected caimans (Caiman crocodilus) and varans (Varanus exanthematicus) have been reported in literature. To determine the distribution patterns of T. zimbabwensis larvae and predilection muscles, 15 crocodiles were randomly divided into three cohorts of five animals each, representing high infection (642 larvae/kg of bodyweight average), medium infection (414 larvae/kg of bodyweight average) and low infection (134 larvae/kg of bodyweight average) cohorts. In the high infection cohort, high percentages of larvae were observed in the triceps muscles (26%) and hind limb muscles (13%). In the medium infection cohort, high percentages of larvae were found in the triceps muscles (50%), sternomastoid (18%) and hind limb muscles (13%). In the low infection cohort, larvae were mainly found in the intercostal muscles (36%), longissimus complex (27%), forelimb muscles (20%) and hind limb muscles (10%). Predilection muscles in the high and medium infection cohorts were similar to those reported in naturally infected crocodiles despite changes in infection intensity. The high infection cohort had significantly higher numbers of larvae in the sternomastoid, triceps, intercostal, longissimus complex, external tibial flexor, longissimus caudalis and caudal femoral muscles (p < 0.05) compared with the medium infection cohort. In comparison with the low infection cohort, the high infection cohort harboured significantly higher numbers of larvae in all muscles (p < 0.05) except for the tongue. The high infection cohort harboured significantly higher numbers of larvae (p < 0.05) in the sternomastoid, triceps, intercostal, longissimus complex

  19. Alginate increases water stability whilst maintaining diet digestibility in farmed saltwater crocodiles ().

    PubMed

    Francis, Magdalene; Morel, Patrick C H; Wilkinson, Brian H P; Wester, Timothy J

    2017-02-01

    Saltwater crocodile () farming in Papua New Guinea is an emerging industry that supplies high-quality skins to the fashion industry. Crocodiles are semiaquatic and fed high-quality feed made from extrudated animal byproducts (i.e., forced through a die at low pressure but not heat treated); however, it disintegrates on contact with water, and this leads to low utilization. Alginate is used extensively in food and pharmaceutical processes because it quickly forms a gel at room temperature; however, its effects on nutrient availability are equivocal, and its utility in crocodile diets is unknown. Extrudated chicken byproduct-based crocodile diets were formulated (as-fed) with and without 1.7 and 3.3% Na alginate with either CaCl or CaCO to cross-link. After immersion in water at 30°C for 24 h, feed retained on a 0.5-mm screen was measured to determine DM retention (DMR). Regardless of inclusion level, alginate addition resulted in a 13-fold increase in DMR ( < 0.05) when CaCO was used as a Ca source; however, CaCl use resulted in a much lower DMR. In a digestibility trial, 10 juvenile crocodiles (2.2 to 2.4 yr of age; 1.2 to 1.9 kg BW) were chosen from farm-raised stocks and fed extrudated chicken byproduct-based diets with and without 1.5% Na alginate and 1.9% CaCO. Animals fed 2% BW for 12 d and with excreta collected the last 5 d were slaughtered and had digesta sampled from the ileum. There were no differences in apparent ileal digestibilities of any AA, N (65.0 vs. 55.8%, SE = 12.2%), and OM (46.8 vs. 39.6%, SE = 12.8%) between diets with and without alginate, respectively. Total-tract digestibilities of OM (69.8 vs. 39.2%, SE = 9.1%) and energy (72.2 vs. 44.4%, SE = 8.3%), however, were greater in alginate-containing diets ( < 0.05). Our study showed that alginate addition to crocodile feed improved its stability in water and did not impair nutrient digestion. Application of these findings should greatly decrease feed wastage, which ultimately will benefit

  20. Capture of farmed Nile crocodiles (Crocodylus niloticus): comparison of physiological parameters after manual capture and after capture with electrical stunning.

    PubMed

    Pfitzer, S; Ganswindt, A; Fosgate, G T; Botha, P J; Myburgh, J G

    2014-09-27

    The electric stunner (e-stunner) is commonly used to handle Nile crocodiles (Crocodylus niloticus) on commercial farms in South Africa, but while it seems to improve handling and safety for the keepers, no information regarding physiological reactions to e-stunning is currently available. The aim of this study was therefore to compare various physiological parameters in farmed C niloticus captured either manually (noosing) or by using an e-stunner. A total of 45 crocodiles were captured at a South African farm by either e-stunning or noosing, and blood samples were taken immediately as well as four hours after capture. Parameters monitored were serum corticosterone, lactate, glucose, as well as alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase and creatine kinase. Lactate concentrations were significantly higher in noosed compared with e-stunned animals (P<0.001). No other blood parameter differed significantly between the two methods of capture. In addition, recorded capture time confirmed that noosing takes significantly longer time compared with e-stunning (P<0.001), overall indicating that e-stunning seems to be the better option for restraint of especially large numbers of crocodiles in a commercial setup because it is quicker, safer and did not cause a significant increase in any of the parameters measured.

  1. Pansteatitis of unknown etiology associated with large-scale Nile crocodile (Crocodylus niloticus) mortality in Kruger National Park, South Africa: pathologic findings.

    PubMed

    Lane, Emily P; Huchzermeyer, Fritz W; Govender, Danny; Bengis, Roy G; Buss, Peter E; Hofmeyr, Markus; Myburgh, Jan G; Steyl, Johan C A; Pienaar, Daniel J; Kotze, Antoinette

    2013-12-01

    Annual mortality events in Nile crocodiles (Crocodylus niloticus) in the Olifants River Gorge in Kruger National Park, South Africa, were experienced between 2008 and 2012, during which at least 216 crocodiles died. Live crocodiles were lethargic. Necropsy examination of 56 affected crocodiles showed dark yellow-brown firm nodules in both somatic fat and the abdominal fat body. In all of the 11 crocodiles submitted for histology, degenerative, necrotic, and inflammatory changes supported a diagnosis of steatitis in both fat types. Crocodiles are apex predators in this anthropogenically changed aquatic ecosystem that is used by humans upstream and downstream from the park for domestic, agricultural, fishing, and recreational purposes. This pathologic review of pansteatitis in crocodiles in the Olifants River system was part of a broad multidisciplinary research program. To date, no definitive causative agent has been identified. Epidemiologic evidence suggests that this event may have been a one-time event with long-standing repercussions on the health of the crocodiles. Pathologic findings are rarely documented in wild crocodilians. This study also reports on other conditions, including the presence of coccidian oocysts, capillarid and filaroid nematodes, digenetic trematodes, and pentastomes.

  2. Experimental inoculation of broad-nosed caimans (Caiman latirostris) and Siamese crocodiles (Crocodylus siamensis) with Mycoplasma alligatoris.

    PubMed

    Pye, G W; Brown, D R; Nogueira, M F; Vliet, K A; Schoeb, T R; Jacobson, E R; Bennett, R A

    2001-06-01

    An outbreak of mycoplasmosis caused by Mycoplasma alligatoris resulted in the death or euthanasia of 60 American alligators (Alligator mississippiensis) from a population of 74 captive bull alligators in Florida in 1995. The natural reservoir, routes of transmission, and host range of M. alligatoris are unknown. This study was undertaken to determine whether crocodilian species other than American alligators are susceptible to M. alligatoris. Six broad-nosed caimans (Caiman latirostris) and six Siamese crocodiles (Crocodylus siamensis) were experimentally inoculated with 10(6) colony forming units (CFU) of M. alligatoris instilled through the glottis. Two caimans and two crocodiles were used as negative controls. Six and four American alligators were used as positive and negative controls, respectively. Three of six (50%) inoculated caimans died within 10 wk postinoculation (PI) of severe mycoplasmosis. Gross necropsy, histopathologic, and culture results were similar for broad-nosed caimans and American alligators. None of the inoculated Siamese crocodiles developed mycoplasmosis, though M. alligatoris was isolated from the tonsils in three of six (50%) animals at necropsy. All the inoculated crocodilians that survived showed significant seroconversion by 6-8-wk PI (P < 0.05). The infective dose 50% (ID50) and lethal dose 50% (LD50) of M. alligatoris for the broad-nosed caiman are 10(6) CFU when instilled through the glottis, which is similar to that of the American alligator. Although the host range of M. alligatoris is not restricted to the American alligator, the organism does not appear to be pathogenic for Siamese crocodiles. Other species of crocodilians may be susceptible to infection with M. alligatoris, and this organism should be considered when the rapid onset of clinical signs of pneumonia, polyarthritis, pericarditis, and death occur.

  3. Inhibition of HeLa cells metastasis by bioactive compounds in crocodile (Crocodylus siamensis) white blood cells extract.

    PubMed

    Patathananone, Supawadee; Thammasirirak, Sompong; Daduang, Jureerut; Gung Chung, Jing; Temsiripong, Yosapong; Daduang, Sakda

    2016-11-01

    Matrix metalloproteinases (MMPs) play a key role in cancer progression, including cell invasion, metastasis, cell growth, apoptosis, angiogenesis, and cell adhesion. Thus, suppression of the MMPs activities is crucial for inhibiting cancer cells metastasis. Herein, bioactive agents from crocodile (Crocodylus siamensis) leukocyte extracts (WBCex) showed the anticancer activity with HeLa cells and inhibited the migration and invasion process by reducing gelatinases (MMP-2, MMP-9) activity and their protein levels. This mechanism is regulated via interfering Ras and p38 signal transduction. Moreover, disrupting VEGF and integrin-signaling cascade by bioactive agents are the predictable mechanisms that cause the decreasing of MMP-2 and MMP-9 activity. Hence, bioactive substances in WBCex may play the mode of action similar with MMPs inhibitor due to HeLa cell metastasis being suppressed in vitro. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1329-1336, 2016.

  4. Normal intestinal flora of wild Nile crocodiles (Crocodylus niloticus) in the Okavango Delta, Botswana.

    PubMed

    Lovely, C J; Leslie, A J

    2008-06-01

    Bacterial and fungal cultures were performed from cloacal swabs collected from 29 wild Nile crocodiles, captured in the Okavango Delta, Botswana. Sixteen species of bacteria and 6 fungal species were cultured. Individual crocodiles yielded 1-4 bacterial species, and 0-2 fungal species. The most commonly isolated bacteria were Microbacterium, Enterococcus faecalis, Aeromonas hydrophila, and Escherichia coli. No salmonellae were cultured. The most commonly occurring fungus was Cladosporium. Several of the bacterial and fungal species isolated have been implicated in cases of septicaemia in crocodilians. Knowledge of the normal intestinal flora will contribute towards the development of a crocodile-specific probiotic for use in farmed crocodiles.

  5. Molecular cloning and characterization of Siamese crocodile (Crocodylus siamensis) copper, zinc superoxide dismutase (CSI-Cu,Zn-SOD) gene.

    PubMed

    Sujiwattanarat, Penporn; Pongsanarakul, Parinya; Temsiripong, Yosapong; Temsiripong, Theeranan; Thawornkuno, Charin; Uno, Yoshinobu; Unajak, Sasimanas; Matsuda, Yoichi; Choowongkomon, Kiattawee; Srikulnath, Kornsorn

    2016-01-01

    Superoxide dismutase (SOD, EC 1.15.1.1) is an antioxidant enzyme found in all living cells. It regulates oxidative stress by breaking down superoxide radicals to oxygen and hydrogen peroxide. A gene coding for Cu,Zn-SOD was cloned and characterized from Siamese crocodile (Crocodylus siamensis; CSI). The full-length expressed sequence tag (EST) of this Cu,Zn-SOD gene (designated as CSI-Cu,Zn-SOD) contained 462bp encoding a protein of 154 amino acids without signal peptides, indicated as intracellular CSI-Cu,Zn-SOD. This agreed with the results from the phylogenetic tree, which indicated that CSI-Cu,Zn-SOD belonged to the intracellular Cu,Zn-SOD. Chromosomal location determined that the CSI-Cu,Zn-SOD was localized to the proximal region of the Siamese crocodile chromosome 1p. Several highly conserved motifs, two conserved signature sequences (GFHVHEFGDNT and GNAGGRLACGVI), and conserved amino acid residues for binding copper and zinc (His(47), His(49), His(64), His(72), His(81), Asp(84), and His(120)) were also identified in CSI-Cu,Zn-SOD. Real-time PCR analysis showed that CSI-Cu,Zn-SOD mRNA was expressed in all the tissues examined (liver, pancreas, lung, kidney, heart, and whole blood), which suggests a constitutively expressed gene in these tissues. Expression of the gene in Escherichia coli cells followed by purification yielded a recombinant CSI-Cu,Zn-SOD, with Km and Vmax values of 6.075mM xanthine and 1.4×10(-3)mmolmin(-1)mg(-1), respectively. This Vmax value was 40 times lower than native Cu,Zn-SOD (56×10(-3)mmolmin(-1)mg(-1)), extracted from crocodile erythrocytes. This suggests that cofactors, protein folding properties, or post-translational modifications were lost during the protein purification process, leading to a reduction in the rate of enzyme activity in bacterial expression of CSI-Cu,Zn-SOD.

  6. Trichinella zimbabwensis in wild Nile crocodiles (Crocodylus niloticus) of South Africa.

    PubMed

    La Grange, Louis J; Marucci, Gianluca; Pozio, Edoardo

    2009-04-06

    Recent discovery of Trichinella zimbabwensis in crocodiles from Zimbabwe, Lake Cahora Basa, Mozambique, and from lake Abaja, Ethiopia, prompted strict control measures to curb the possible spread of the infection to humans and also to prevent its introduction to other countries, which were considered free of this pathogen. In 2006, the Chief Directorate Veterinary Services of Mpumalanga Province of South Africa launched a survey to investigate the status of wild and commercial breeding crocodiles in the province. To evaluate if T. zimbabwensis was circulating in the environments where crocodiles are living in South Africa, 9 fish, 36 reptiles (including 27 Nile crocodiles) and 4 mammals have been investigated to detect Trichinella sp. larvae in their muscles. In January 2008, a Nile crocodile from Komatipoort, sampled by means of a tail biopsy, tested positive for Trichinella larvae. In June-July 2008, Trichinella sp. larvae were also detected in four other Nile crocodiles from the Olifants River Gorge. The prevalence of Trichinella infection in the investigated wild Nile crocodiles from South Africa is 38.5%. The larvae were identified as belonging to T. zimbabwensis by multiplex-PCR. These are the first reports of T. zimbabwensis in South Africa and suggest that the distribution area of this parasite species is wider than that believed in the past.

  7. Identification and characterization of dipeptidyl peptidase IV enzyme activity in the American crocodile (Crocodylus acutus).

    PubMed

    Merchant, Mark; Mead, Stephanie; McAdon, Charles; McFatter, Justin; Wasilewski, Joe

    2010-07-01

    Serum from the American crocodile was assayed for dipeptidyl peptidase IV (DPP4) activity. We measured the DPP4-mediated hydrolysis of Ala-Pro-AFC. The generation of AFC was dependent on the titer of serum, with significant DPP4 activity (0.20 + or - 0.03 nmol product formed) measured using only 2 microL of crocodile serum, with maximum activity measured using 500 microL of serum. The hydrolysis of substrate was inhibited in a concentration-dependent manner by diprotin A, a specific inhibitor of DPP4 activity, indicating that this activity was due to the presence of DPP4. The crocodile serum DPP4 exhibited classical Michaelis-Menten kinetics, with K(m) and V(max) extrapolated, by double-reciprocal plot, to be 14.7 + or - 1.3 microM and 75.5 + or - 4.3 nmol/min, respectively. Crocodile DPP4 catalyzed the hydrolysis of Ala-Pro-AFC rapidly, with substantial activity measured within 5 min of the addition of substrate. After an initial rapid increase in activity, near maximal activity (7.43 + or - 0.24 nmol product formed) measured at 180 min. Crocodile serum DPP4 activity was temperature-dependent, with steadily increased activity from 5 to 40 degrees C.

  8. Diving in a warming world: the thermal sensitivity and plasticity of diving performance in juvenile estuarine crocodiles (Crocodylus porosus)

    PubMed Central

    Rodgers, Essie M.; Schwartz, Jonathon J.; Franklin, Craig E.

    2015-01-01

    Air-breathing, diving ectotherms are a crucial component of the biodiversity and functioning of aquatic ecosystems, but these organisms may be particularly vulnerable to the effects of climate change on submergence times. Ectothermic dive capacity is thermally sensitive, with dive durations significantly reduced by acute increases in water temperature; it is unclear whether diving performance can acclimate/acclimatize in response to long-term exposure to elevated water temperatures. We assessed the thermal sensitivity and plasticity of ‘fright-dive’ capacity in juvenile estuarine crocodiles (Crocodylus porosus; n = 11). Crocodiles were exposed to one of three long-term thermal treatments, designed to emulate water temperatures under differing climate change scenarios (i.e. current summer, 28°C; ‘moderate’ climate warming, 31.5°C; ‘high’ climate warming, 35°C). Dive trials were conducted in a temperature-controlled tank across a range of water temperatures. Dive durations were independent of thermal acclimation treatment, indicating a lack of thermal acclimation response. Acute increases in water temperature resulted in significantly shorter dive durations, with mean submergence times effectively halving with every 3.5°C increase in water temperature (Q10 0.17, P < 0.001). Maximal dive performances, however, were found to be thermally insensitive across the temperature range of 28–35°C. These results suggest that C. porosus have a limited or non-existent capacity to thermally acclimate sustained ‘fright-dive’ performance. If the findings here are applicable to other air-breathing, diving ectotherms, the functional capacity of these organisms will probably be compromised under climate warming. PMID:27293738

  9. Diving in a warming world: the thermal sensitivity and plasticity of diving performance in juvenile estuarine crocodiles (Crocodylus porosus).

    PubMed

    Rodgers, Essie M; Schwartz, Jonathon J; Franklin, Craig E

    2015-01-01

    Air-breathing, diving ectotherms are a crucial component of the biodiversity and functioning of aquatic ecosystems, but these organisms may be particularly vulnerable to the effects of climate change on submergence times. Ectothermic dive capacity is thermally sensitive, with dive durations significantly reduced by acute increases in water temperature; it is unclear whether diving performance can acclimate/acclimatize in response to long-term exposure to elevated water temperatures. We assessed the thermal sensitivity and plasticity of 'fright-dive' capacity in juvenile estuarine crocodiles (Crocodylus porosus; n = 11). Crocodiles were exposed to one of three long-term thermal treatments, designed to emulate water temperatures under differing climate change scenarios (i.e. current summer, 28°C; 'moderate' climate warming, 31.5°C; 'high' climate warming, 35°C). Dive trials were conducted in a temperature-controlled tank across a range of water temperatures. Dive durations were independent of thermal acclimation treatment, indicating a lack of thermal acclimation response. Acute increases in water temperature resulted in significantly shorter dive durations, with mean submergence times effectively halving with every 3.5°C increase in water temperature (Q 10 0.17, P < 0.001). Maximal dive performances, however, were found to be thermally insensitive across the temperature range of 28-35°C. These results suggest that C. porosus have a limited or non-existent capacity to thermally acclimate sustained 'fright-dive' performance. If the findings here are applicable to other air-breathing, diving ectotherms, the functional capacity of these organisms will probably be compromised under climate warming.

  10. The relationship between early growth and survival of hatchling saltwater crocodiles (Crocodylus porosus) in captivity.

    PubMed

    Brien, Matthew L; Webb, Grahame J; McGuinness, Keith; Christian, Keith A

    2014-01-01

    Hatchling fitness in crocodilians is affected by "runtism" or failure to thrive syndrome (FTT) in captivity. In this study, 300 hatchling C. porosus, artificially incubated at 32°C for most of their embryonic development, were raised in semi-controlled conditions, with growth criteria derived for the early detection of FTT (within 24 days). Body mass, four days after hatching (BM4d), was correlated with egg size and was highly clutch specific, while snout-vent length (SVL4d) was much more variable within and between clutches. For the majority of hatchlings growth trajectories within the first 24 days continued to 90 days and could be used to predict FTT affliction up to 300 days, highlighting the importance of early growth. Growth and survival of hatchling C. porosus in captivity was not influenced by initial size (BM4d), with a slight tendency for smaller hatchlings to grow faster in the immediate post-hatching period. Strong clutch effects (12 clutches) on affliction with FTT were apparent, but could not be explained by measured clutch variables or other factors. Among individuals not afflicted by FTT (N = 245), mean growth was highly clutch specific, and the variation could be explained by an interaction between clutch and season. FTT affliction was 2.5 times higher among clutches (N = 7) that hatched later in the year when mean minimum air temperatures were lower, compared with those clutches (N = 5) that hatched early in the year. The results of this study highlight the importance of early growth in hatchling C. porosus, which has implications for the captive management of this species.

  11. The Relationship between Early Growth and Survival of Hatchling Saltwater Crocodiles (Crocodylus porosus) in Captivity

    PubMed Central

    Brien, Matthew L.; Webb, Grahame J.; McGuinness, Keith; Christian, Keith A.

    2014-01-01

    Hatchling fitness in crocodilians is affected by “runtism” or failure to thrive syndrome (FTT) in captivity. In this study, 300 hatchling C. porosus, artificially incubated at 32°C for most of their embryonic development, were raised in semi-controlled conditions, with growth criteria derived for the early detection of FTT (within 24 days). Body mass, four days after hatching (BM4d), was correlated with egg size and was highly clutch specific, while snout-vent length (SVL4d) was much more variable within and between clutches. For the majority of hatchlings growth trajectories within the first 24 days continued to 90 days and could be used to predict FTT affliction up to 300 days, highlighting the importance of early growth. Growth and survival of hatchling C. porosus in captivity was not influenced by initial size (BM4d), with a slight tendency for smaller hatchlings to grow faster in the immediate post-hatching period. Strong clutch effects (12 clutches) on affliction with FTT were apparent, but could not be explained by measured clutch variables or other factors. Among individuals not afflicted by FTT (N = 245), mean growth was highly clutch specific, and the variation could be explained by an interaction between clutch and season. FTT affliction was 2.5 times higher among clutches (N = 7) that hatched later in the year when mean minimum air temperatures were lower, compared with those clutches (N = 5) that hatched early in the year. The results of this study highlight the importance of early growth in hatchling C. porosus, which has implications for the captive management of this species. PMID:24960026

  12. Nest-site selection, nesting behaviour and spatial ecology of female Nile crocodiles (Crocodylus niloticus) in South Africa.

    PubMed

    Combrink, Xander; Warner, Jonathan K; Downs, Colleen T

    2017-02-01

    Nesting biology and ecology have been investigated for Nile crocodiles (Crocodylus niloticus), but information on behaviour and movement patterns of nesting females during nest guarding is scant. Consequently, we investigated the home ranges, nest-site selection strategies, movement patterns, activity levels and nest fidelity of four nesting females using telemetry. Gravid females selected winter basking/breeding areas close (351±2m) to nest-sites. Mean home range and core-use areas of nesting females were 8539±4752m(2), and 4949±3302m(2) respectively. Mean home range (0.85ha) was significantly smaller than those of non-nesting females (108.4ha) during nesting season. Activity levels and mean daily movements while nesting were 8.1±2.5% and 213±64m, respectively, and increased to 47.9±11.7% and 2176±708m post-nesting. Overall levels of nest fidelity were 82.8±11.7%, (day 78.1±15.9%; night 87.3±7.8%). Highest nest fidelity recorded during incubation was 99.7% over 96days. Telemetry data from nesting females were helpful for elucidating spatial and behavioural patterns during the nest guarding period, and provided novel insights into this biologically important event.

  13. Gastric nematodes of nile crocodiles, Crocodylus niloticus Laurenti, 1768, in the Okavango River, Botswana.

    PubMed

    Junker, K; Wallace, K; Leslie, A J; Boomker, J

    2006-06-01

    The ascaridoid nematodes Dujardinascaris madagascariensis Chabaud & Caballero, 1966, Dujardinascaris dujardini (Travassos, 1920), Gedoelstascaris vandenbrandeni (Baylis, 1929) Sprent, 1978 and Multicaecum agile (Wedl, 1861) Baylis, 1923 were recovered from the stomach contents of Crocodylus niloticus Laurenti, 1768 from the Okavango River, Botswana, together with Eustrongylides sp., a dioctophymatoid nematode usually parasitizing piscivorous birds. Dujardinascaris madagascariensis was present in most of the infected hosts, while the remaining species were mostly represented in single collections in one to three hosts. All four ascaridoid nematodes represent new geographic records.

  14. Biotransformation and Oxidative Stress Responses in Captive Nile Crocodile (Crocodylus niloticus) Exposed to Organic Contaminants from the Natural Environment in South Africa.

    PubMed

    Arukwe, Augustine; Røsbak, Randi; Adeogun, Aina O; Langberg, Håkon A; Venter, Annette; Myburgh, Jan; Botha, Christo; Benedetti, Maura; Regoli, Francesco

    2015-01-01

    In the present study, the biotransformation and oxidative stress responses in relation to chemical burden in the liver of male and female Nile crocodiles--Crocodylus niloticus--from a commercial crocodile farm passively exposed to various anthropogenic aquatic pollutants was investigated. In general, the data showed that male crocodiles consistently produced higher biotransformation and oxidative stress responses compared to females. Relationships between these responses and concentrations of aliphatic hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) were also observed. Specifically, the catalytic assays for EROD and BROD (not PROD and MROD) showed sex-differences between male and female crocodiles and paralleled immunochemically determined CYP1A and CYP3A protein levels; the relatively similar levels of PAHs in both sexes suggest an estrogen-mediated reduction of this pathway in females. The antioxidant system exhibited higher levels in male crocodiles with slight or significant higher values for catalase (CAT), glutathione reductase (GR), glutathione peroxidases-H2O2 (GPx-H2O2), glutathione peroxidases-Cu (GPx-Cu), total antioxidant capacity towards peroxyl radicals (TOSC-ROO) and hydroxyl radicals (TOSC-HO), total glutathione (GSH) and malondialdehyde (MDA). On the other hand, the activities of acyl-CoA oxidase (AOX) and glutathione S-transferases (GST) were significantly higher in females. Principal component analysis (PCA) produced significant groupings that revealed correlative relationships (both positive and negative) between biotransformation/oxidative stress variables and liver PAHs and aliphatic hydrocarbon burden. The overall results suggest that these captive pre-slaughter crocodiles exhibited adverse exposure responses to anthropogenic aquatic contaminants with potentially relevant effects on key cellular pathways, and these responses may be established as relevant species biomarkers of exposure and effects in this endangered species.

  15. An experimental and morphometric test of the relationship between vertebral morphology and joint stiffness in Nile crocodiles (Crocodylus niloticus).

    PubMed

    Molnar, Julia L; Pierce, Stephanie E; Hutchinson, John R

    2014-03-01

    Despite their semi-aquatic mode of life, modern crocodylians use a wide range of terrestrial locomotor behaviours, including asymmetrical gaits otherwise only found in mammals. The key to these diverse abilities may lie in the axial skeleton. Correlations between vertebral morphology and both intervertebral joint stiffness and locomotor behaviour have been found in other animals, but the vertebral mechanics of crocodylians have not yet been experimentally and quantitatively tested. We measured the passive mechanics and morphology of the thoracolumbar vertebral column in Crocodylus niloticus in order to validate a method to infer intervertebral joint stiffness based on morphology. Passive stiffness of eight thoracic and lumbar joints was tested in dorsal extension, ventral flexion and mediolateral flexion using cadaveric specimens. Fifteen measurements that we deemed to be potential correlates of stiffness were taken from each vertebra and statistically tested for correlation with joint stiffness. We found that the vertebral column of C. niloticus is stiffer in dorsoventral flexion than in lateral flexion and, in contrast to that of many mammals, shows an increase in joint stiffness in the lumbar region. Our findings suggest that the role of the axial column in crocodylian locomotion may be functionally different from that in mammals, even during analogous gaits. A moderate proportion of variation in joint stiffness (R(2)=0.279-0.520) was predicted by centrum width and height, neural spine angle and lamina width. These results support the possible utility of some vertebral morphometrics in predicting mechanical properties of the vertebral column in crocodiles, which also should be useful for forming functional hypotheses of axial motion during locomotion in extinct archosaurs.

  16. Mitochondrial DNA analysis reveals hidden genetic diversity in captive populations of the threatened American crocodile (Crocodylus acutus) in Colombia

    PubMed Central

    Bloor, Paul; Ibáñez, Carolina; Viloria-Lagares, Thomas A

    2015-01-01

    Identification of units within species worthy of separate management consideration is an important area within conservation. Mitochondrial DNA (mtDNA) surveys can potentially contribute to this by identifying phylogenetic and population structure below the species level. The American crocodile (Crocodylus acutus) is broadly distributed throughout the Neotropics. Its numbers have been reduced severely with the species threatened throughout much of its distribution. In Colombia, the release of individuals from commercial captive populations has emerged as a possible conservation strategy that could contribute to species recovery. However, no studies have addressed levels of genetic differentiation or diversity within C. acutus in Colombia, thus complicating conservation and management decisions. Here, sequence variation was studied in mtDNA cytochrome b and cytochrome oxidase I gene sequences in three Colombian captive populations of C. acutus. Two distinct lineages were identified: C. acutus-I, corresponding to haplotypes from Colombia and closely related Central American haplotypes; and C. acutus-II, corresponding to all remaining haplotypes from Colombia. Comparison with findings from other studies indicates the presence of a single “northern” lineage (corresponding to C. acutus-I) distributed from North America (southern Florida), through Central America and into northern South America. The absence of C. acutus-II haplotypes from North and Central America indicates that the C. acutus-II lineage probably represents a separate South American lineage. There appears to be sufficient divergence between lineages to suggest that they could represent two distinct evolutionary units. We suggest that this differentiation needs to be recognized for conservation purposes because it clearly contributes to the overall genetic diversity of the species. All Colombian captive populations included in this study contained a mixture of representatives of both lineages. As

  17. The accessory role of the diaphragmaticus muscle in lung ventilation in the estuarine crocodile Crocodylus porosus.

    PubMed

    Munns, Suzanne L; Owerkowicz, Tomasz; Andrewartha, Sarah J; Frappell, Peter B

    2012-03-01

    Crocodilians use a combination of three muscular mechanisms to effect lung ventilation: the intercostal muscles producing thoracic movement, the abdominal muscles producing pelvic rotation and gastralial translation, and the diaphragmaticus muscle producing visceral displacement. Earlier studies suggested that the diaphragmaticus is a primary muscle of inspiration in crocodilians, but direct measurements of the diaphragmatic contribution to lung ventilation and gas exchange have not been made to date. In this study, ventilation, metabolic rate and arterial blood gases were measured from juvenile estuarine crocodiles under three conditions: (i) while resting at 30°C and 20°C; (ii) while breathing hypercapnic gases; and (iii) during immediate recovery from treadmill exercise. The relative contribution of the diaphragmaticus was then determined by obtaining measurements before and after transection of the muscle. The diaphragmaticus was found to make only a limited contribution to lung ventilation while crocodiles were resting at 30°C and 20°C, and during increased respiratory drive induced by hypercapnic gas. However, the diaphragmaticus muscle was found to play a significant role in facilitating a higher rate of inspiratory airflow in response to exercise. Transection of the diaphragmaticus decreased the exercise-induced increase in the rate of inspiration (with no compensatory increases in the duration of inspiration), thus compromising the exercise-induced increases in tidal volume and minute ventilation. These results suggest that, in C. porosus, costal ventilation alone is able to support metabolic demands at rest, and the diaphragmaticus is largely an accessory muscle used at times of elevated metabolic demand.

  18. The continuously growing central nervous system of the Nile crocodile (Crocodylus niloticus).

    PubMed

    Ngwenya, Ayanda; Patzke, Nina; Spocter, Muhammad A; Kruger, Jean-Leigh; Dell, Leigh-Anne; Chawana, Richard; Mazengenya, Pedzisai; Billings, Brendon K; Olaleye, Olatunbosun; Herculano-Houzel, Suzana; Manger, Paul R

    2013-10-01

    It is a central assumption that larger bodies require larger brains, across species but also possibly within species with continuous growth throughout the lifetime, such as the crocodile. The current study investigates the relationships between body growth (length and mass) and the rates of growth of various subdivisions of the central nervous system (CNS) (brain, spinal cord, eyes) in Nile crocodiles weighing between 90 g and 90 kg. Although the brain appears to grow in two phases in relation to body mass, initially very rapidly then very slowly, it turns out that brain mass increases continuously as a power function of body mass with a small exponent of 0.256, such that a 10-fold increase in body mass is accompanied by a 1.8-fold in brain mass. Eye volume increases slowly with increasing body mass, as a power function of the latter with an exponent of 0.37. The spinal cord, however, grows more rapidly in mass, accompanying body mass raised to an exponent of 0.54, and increasing in length as predicted, with body mass raised to an exponent of 0.32 (close to the predicted 1/3). While supporting the expectation formulated by Jerison that larger bodies require larger brains to operate them, our findings show that: (1) the rate of increase in brain size is very small compared to body growth; and (2) different parts of the CNS grow at different rates accompanying continuous body growth, with a faster increase in spinal cord mass and eye volume, than in brain mass.

  19. Biotransformation and Oxidative Stress Responses in Captive Nile Crocodile (Crocodylus niloticus) Exposed to Organic Contaminants from the Natural Environment in South Africa

    PubMed Central

    Arukwe, Augustine; Røsbak, Randi; Adeogun, Aina O.; Langberg, Håkon A.; Venter, Annette; Myburgh, Jan; Botha, Christo; Benedetti, Maura; Regoli, Francesco

    2015-01-01

    In the present study, the biotransformation and oxidative stress responses in relation to chemical burden in the liver of male and female Nile crocodiles—Crocodylus niloticus—from a commercial crocodile farm passively exposed to various anthropogenic aquatic pollutants was investigated. In general, the data showed that male crocodiles consistently produced higher biotransformation and oxidative stress responses compared to females. Relationships between these responses and concentrations of aliphatic hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) were also observed. Specifically, the catalytic assays for EROD and BROD (not PROD and MROD) showed sex-differences between male and female crocodiles and paralleled immunochemically determined CYP1A and CYP3A protein levels; the relatively similar levels of PAHs in both sexes suggest an estrogen-mediated reduction of this pathway in females. The antioxidant system exhibited higher levels in male crocodiles with slight or significant higher values for catalase (CAT), glutathione reductase (GR), glutathione peroxidases-H2O2 (GPx-H2O2), glutathione peroxidases-Cu (GPx-Cu), total antioxidant capacity towards peroxyl radicals (TOSC-ROO) and hydroxyl radicals (TOSC-HO), total glutathione (GSH) and malondialdehyde (MDA). On the other hand, the activities of acyl-CoA oxidase (AOX) and glutathione S-transferases (GST) were significantly higher in females. Principal component analysis (PCA) produced significant groupings that revealed correlative relationships (both positive and negative) between biotransformation/oxidative stress variables and liver PAHs and aliphatic hydrocarbon burden. The overall results suggest that these captive pre-slaughter crocodiles exhibited adverse exposure responses to anthropogenic aquatic contaminants with potentially relevant effects on key cellular pathways, and these responses may be established as relevant species biomarkers of exposure and effects in this endangered species. PMID

  20. The post-occipital spinal venous sinus of the Nile crocodile Crocodylus niloticus: its anatomy and use for blood sample collection and intravenous infusions.

    PubMed

    Myburgh, Jan G; Kirberger, Robert M; Steyl, Johan C A; Soley, John T; Booyse, Dirk G; Huchzermeyer, Fritz W; Lowers, Russel H; Guillette, Louis J

    2014-05-05

    The post-occipital sinus of the spinal vein is often used for the collection of blood samples from crocodilians. Although this sampling method has been reported for several crocodilian species, the technique and associated anatomy has not been described in detail in any crocodilian, including the Nile crocodile (Crocodylus niloticus). The anatomy of the cranial neck region was investigated macroscopically, microscopically, radiographically and by means of computed tomography. Latex was injected into the spinal vein and spinal venous sinus of crocodiles to visualise the regional vasculature. The spinal vein ran within the vertebral canal, dorsal to and closely associated with the spinal cord and changed into a venous sinus cranially in the post-occipital region. For blood collection, the spinal venous sinus was accessed through the interarcuate space between the atlas and axis (C1 and C2) by inserting a needle angled just off the perpendicular in the midline through the craniodorsal cervical skin, just cranial to the cranial borders of the first cervical osteoderms. The most convenient method of blood collection was with a syringe and hypodermic needle. In addition, the suitability of the spinal venous sinus for intravenous injections and infusions in live crocodiles was evaluated. The internal diameter of the commercial human epidural catheters used during these investigations was relatively small, resulting in very slow infusion rates. Care should be taken not to puncture the spinal cord or to lacerate the blood vessel wall using this route for blood collection or intravenous infusions.

  1. Comparative analysis of hatching rates and clutch sizes of Nile crocodile (Crocodylus niloticus) eggs collected on- and off-farm in Zimbabwe.

    PubMed

    Khosa, Patricia; Imbayarwo-Chikosi, Venancio Edward; Hamandishe, Vimbai

    2012-04-01

    The Nile crocodile (Crocodylus niloticus) is a large aquatic reptile predominant in the tropics in Africa and Zimbabwe in particular. Clutch sizes and hatching rates of Nile crocodile eggs collected from the wild and on-farm in Lowveld, Highveld and Kariba regions of Zimbabwe were evaluated. A total of 274 egg records for the period 2000 to 2008 from 39 farms were collected from the Crocodile Farmers Association of Zimbabwe. The effect of source of eggs was analysed using the non-parametric one way analysis of variance procedure of SAS Version 9.1.3. Wilcoxon signed rank test for independent samples was used to compare the mean hatching rates and clutch sizes for eggs collected from the different sources by region. The degree of association between clutch sizes and the hatching rates by source and region was determined using the Spearman's rank correlation test. Source of eggs had no effect (P > 0.05) on hatching rates in all the regions but significantly influenced (P < 0.05) clutch sizes in Lowveld and Kariba. In these regions, clutch sizes in the wild were significantly (P < 0.05) higher than those on-farm. Correlation estimates between clutch size and hatching rates were weak and non-significant (P > 0.05) for the different sources of eggs in all regions. Full utilization of the wild resource would reduce challenges relating to shortage of captive breeders and high cost of rearing breeders and hence increase productivity.

  2. Spatial Ecology of Estuarine Crocodile (Crocodylus porosus) Nesting in a Fragmented Landscape.

    PubMed

    Evans, Luke J; Jones, T Hefin; Pang, Keeyen; Saimin, Silvester; Goossens, Benoit

    2016-09-19

    The role that oil palm plays in the Lower Kinabatangan region of Eastern Sabah is of considerable scientific and conservation interest, providing a model habitat for many tropical regions as they become increasingly fragmented. Crocodilians, as apex predators, widely distributed throughout the tropics, are ideal indicator species for ecosystem health. Drones (or unmanned aerial vehicles (UAVs)) were used to identify crocodile nests in a fragmented landscape. Flights were targeted through the use of fuzzy overlay models and nests located primarily in areas indicated as suitable habitat. Nests displayed a number of similarities in terms of habitat characteristics allowing for refined modelling of survey locations. As well as being more cost-effective compared to traditional methods of nesting survey, the use of drones also enabled a larger survey area to be completed albeit with a limited number of flights. The study provides a methodology for targeted nest surveying, as well as a low-cost repeatable flight methodology. This approach has potential for widespread applicability across a range of species and for a variety of study designs.

  3. Spatial Ecology of Estuarine Crocodile (Crocodylus porosus) Nesting in a Fragmented Landscape

    PubMed Central

    Evans, Luke J.; Jones, T. Hefin; Pang, Keeyen; Saimin, Silvester; Goossens, Benoit

    2016-01-01

    The role that oil palm plays in the Lower Kinabatangan region of Eastern Sabah is of considerable scientific and conservation interest, providing a model habitat for many tropical regions as they become increasingly fragmented. Crocodilians, as apex predators, widely distributed throughout the tropics, are ideal indicator species for ecosystem health. Drones (or unmanned aerial vehicles (UAVs)) were used to identify crocodile nests in a fragmented landscape. Flights were targeted through the use of fuzzy overlay models and nests located primarily in areas indicated as suitable habitat. Nests displayed a number of similarities in terms of habitat characteristics allowing for refined modelling of survey locations. As well as being more cost-effective compared to traditional methods of nesting survey, the use of drones also enabled a larger survey area to be completed albeit with a limited number of flights. The study provides a methodology for targeted nest surveying, as well as a low-cost repeatable flight methodology. This approach has potential for widespread applicability across a range of species and for a variety of study designs. PMID:27657065

  4. Effect of nesting environment on incubation temperature and hatching success of Morelet's crocodile (Crocodylus moreletii) in an urban lake of Southeastern Mexico.

    PubMed

    López-Luna, Marco A; Hidalgo-Mihart, Mircea G; Aguirre-León, Gustavo; González-Ramón, Mariana Del C; Rangel-Mendoza, Judith A

    2015-01-01

    Incubation temperature is an important aspect in terms of biological performance among crocodiles, and several controlled experiments have demonstrated a significant relationship between incubation temperature, success in hatching and survival of hatchlings. However, a few studies have tested these relationships in the wild. The objective of this study was to determine the relationship of nest characteristics and environment (hatch year, nest basal area and height, clutch size, distance to shore line, and vegetation cover), to incubation temperature and hatching success among Morelet's crocodile (Crocodylus moreletii). The study was carried out during the nesting seasons of Morelet's crocodile, from 2007 to 2009 in the Laguna de Las Ilusiones, an urban lake located in Villahermosa, Tabasco, Mexico. We physically characterized 18 nests and inserted a temperature data logger in each nest chamber. At the end of the nesting season and prior to hatching, we recovered the crocodile eggs and data loggers and calculated hatching success, under laboratory conditions. We related the environmental variables of the nest with the mean and fluctuation (standard deviation) of nest temperature, using linear models. We also related the environmental variables affecting the nest, to mean nest temperature and fluctuation in incubation temperature and to hatching success, using linear models. Although we found differences in incubation temperature between nests, mean incubation temperature did not differ between years, but there were differences in nest thermal fluctuation between years. The mean incubation temperature for 11 nests (61.1%) was lower than the suggested Female-Male pivotal temperature (producing 50% of each sex) for this species, and all hatchlings obtained were males. There were no differences in clutch size between years, but hatching success varied. Our study indicates that hatching success depends on certain environmental variables and nest conditions to which the

  5. Element concentrations in the flesh and osteoderms of estuarine crocodiles (Crocodylus porosus) from the Alligator Rivers Region, Northern Australia: biotic and geographic effects.

    PubMed

    Jeffree, R A; Markich, S J; Twining, J R

    2001-02-01

    The concentrations of Na, K, Ca, Mg, Ba, Sr, Fe, Al, Mn, Zn, Pb, Cu, Ni, Cr, Co, Se, U, and Ti were determined in the flesh and osteoderms of estuarine crocodiles (Crocodylus porosus) captured in three adjacent catchments of Kakadu National Park, within the Alligator Rivers Region of northern Australia. This study provides, for the first-time, baseline concentrations of elements in both flesh and osteoderms of wild crocodiles. Multiple linear regression analyses were used to determine the effects of total crocodile length, estimated age, gender, inferred reproductive status, physical condition, and catchment of capture on element concentrations in both tissues. The Mg concentration (log10) in the flesh and osteoderms of C. porosus significantly (p < or = 0.001) decreased with increasing length (1.7-5.0 m) and estimated age (5-40 years). Similarly, the Ti concentration (log10) in flesh significantly (p < or = 0.01) decreased with increasing length. In contrast, Zn and Se concentration (log10) in flesh significantly (p < or = 0.001) increased with increasing length and/or age, suggesting that these relationships are mediated by biological rather than environmental chemical factors. In flesh, Fe and Na concentrations (log10) significantly (p < or = 0.05) increased as the physical condition of C. porosus deteriorated. No significant (p > 0.05) effects of gender or inferred reproductive status on element concentrations in the flesh and osteoderms were found. The mean concentrations (log10) of Al, Ba, Cr, Ni, and Pb in flesh and Co, Fe, Mg, Mn, and U in the osteoderms were significantly (p < or = 0.01) different between catchments. The significant (p < or = 0.05) effects of catchment on the concentrations of various elements indicate that C. porosus reflects the chemistry of its environmental milieu and therefore has a certain degree of catchment fidelity, even though the catchments are adjacent to one another. Such catchment-specific signals may be useful in the

  6. First evidence of higher female recombination in a species with temperature-dependent sex determination: the saltwater crocodile.

    PubMed

    Isberg, Sally Robyn; Johnston, Scott Maxwell; Chen, Yizhou; Moran, Christopher

    2006-01-01

    The first evidence of genetic linkage and sex-specific recombination in the order Crocodylia is reported. This study was conducted using a resource pedigree of saltwater crocodiles consisting of 16 known-breeding pairs (32 adults) and 101 juveniles. A total of 21 microsatellite loci were available for analysis. Ten of the 21 loci showed linkage with 4 linkage groups: 3 pairwise (Cj131/Cj127, CUD68/Cj101, and Cj107/Cp10) and 1 four-locus (Cj122, CUD78, Cj16, and Cj104) being found. Linkage analysis on the 21 loci revealed evidence of sex-specific differences in recombination rates. All 5 nonzero interlocus intervals were longer in females than in males, with the 4-loci linkage group 3-fold longer in females than in males (41.63 cM and 14.1 cM, respectively). This is the first report of sex-specific recombination rates in a species that exhibits temperature-dependent sex determination.

  7. Multiple Paternity in a Reintroduced Population of the Orinoco Crocodile (Crocodylus intermedius) at the El Frío Biological Station, Venezuela.

    PubMed

    Rossi Lafferriere, Natalia A; Antelo, Rafael; Alda, Fernando; Mårtensson, Dick; Hailer, Frank; Castroviejo-Fisher, Santiago; Ayarzagüena, José; Ginsberg, Joshua R; Castroviejo, Javier; Doadrio, Ignacio; Vilá, Carles; Amato, George

    2016-01-01

    The success of a reintroduction program is determined by the ability of individuals to reproduce and thrive. Hence, an understanding of the mating system and breeding strategies of reintroduced species can be critical to the success, evaluation and effective management of reintroduction programs. As one of the most threatened crocodile species in the world, the Orinoco crocodile (Crocodylus intermedius) has been reduced to only a few wild populations in the Llanos of Venezuela and Colombia. One of these populations was founded by reintroduction at Caño Macanillal and La Ramera lagoon within the El Frío Biological Station, Venezuela. Twenty egg clutches of C. intermedius were collected at the El Frío Biological Station for incubation in the lab and release of juveniles after one year. Analyzing 17 polymorphic microsatellite loci from 335 hatchlings we found multiple paternity in C. intermedius, with half of the 20 clutches fathered by two or three males. Sixteen mothers and 14 fathers were inferred by reconstruction of multilocus parental genotypes. Our findings showed skewed paternal contributions to multiple-sired clutches in four of the clutches (40%), leading to an overall unequal contribution of offspring among fathers with six of the 14 inferred males fathering 90% of the total offspring, and three of those six males fathering more than 70% of the total offspring. Our results provide the first evidence of multiple paternity occurring in the Orinoco crocodile and confirm the success of reintroduction efforts of this critically endangered species in the El Frío Biological Station, Venezuela.

  8. Multiple Paternity in a Reintroduced Population of the Orinoco Crocodile (Crocodylus intermedius) at the El Frío Biological Station, Venezuela

    PubMed Central

    Alda, Fernando; Mårtensson, Dick; Hailer, Frank; Castroviejo-Fisher, Santiago; Ginsberg, Joshua R.; Castroviejo, Javier; Doadrio, Ignacio; Vilá, Carles; Amato, George

    2016-01-01

    The success of a reintroduction program is determined by the ability of individuals to reproduce and thrive. Hence, an understanding of the mating system and breeding strategies of reintroduced species can be critical to the success, evaluation and effective management of reintroduction programs. As one of the most threatened crocodile species in the world, the Orinoco crocodile (Crocodylus intermedius) has been reduced to only a few wild populations in the Llanos of Venezuela and Colombia. One of these populations was founded by reintroduction at Caño Macanillal and La Ramera lagoon within the El Frío Biological Station, Venezuela. Twenty egg clutches of C. intermedius were collected at the El Frío Biological Station for incubation in the lab and release of juveniles after one year. Analyzing 17 polymorphic microsatellite loci from 335 hatchlings we found multiple paternity in C. intermedius, with half of the 20 clutches fathered by two or three males. Sixteen mothers and 14 fathers were inferred by reconstruction of multilocus parental genotypes. Our findings showed skewed paternal contributions to multiple-sired clutches in four of the clutches (40%), leading to an overall unequal contribution of offspring among fathers with six of the 14 inferred males fathering 90% of the total offspring, and three of those six males fathering more than 70% of the total offspring. Our results provide the first evidence of multiple paternity occurring in the Orinoco crocodile and confirm the success of reintroduction efforts of this critically endangered species in the El Frío Biological Station, Venezuela. PMID:26982578

  9. A preliminary disease survey in the wild Nile crocodile (Crocodylus niloticus) population in the Okavango Delta, Botswana.

    PubMed

    Leslie, A J; Lovely, C J; Pittman, J M

    2011-09-01

    The objective of this study was to conduct a preliminary survey of diseases that might be present in the wild Nile crocodile population in the Okavango Delta, Botswana. Blood samples were collected from crocodiles ranging in size from 34.0 cm to 463.0 cm total length. Samples were examined for blood parasites and underwent a haematological analysis. Before release the crocodiles were examined for various clinical abnormalities. Of the 144 crocodiles examined, none were visibly sick or displayed any signs of disease. No antibodies to Mycoplasma crocodyli were detected. Hepatozoon pettiti was present in 55.3% of blood smears examined, but there was no significant difference in any of the haematological values between the infected and uninfected crocodiles, and a high prevalence of Hepatozoon infection is not uncommon in other species. Only 7.6% of the examined crocodiles were infested with leeches. Further research is required for several of the crocodilian diseases, in particular to elucidate the role of wild crocodilians as reservoirs of infection.

  10. Use of immunoblotting to detect antibodies to Mycoplasma crocodyli infection in the sera of crocodiles (Crocodylus niloticus).

    PubMed

    Dawo, Fufa; Mohan, Krishna

    2008-02-01

    An immunoblotting protocol for the detection of antibodies to Mycoplasma crocodyli was developed using sonicated antigen of the reference strain 266/93. Immunoblotting detected nine reacting antigens, of which the 33 and 40kDa antigens were immunodominant. There was no difference in reactivity of the antigens against sera obtained from vaccinated and infected crocodiles. Both antigens are candidates for other serological and molecular studies. This is the first report to develop and apply an immunoblotting test for detection of antibody to M. crocodyli infection in crocodiles.

  11. Detection of antibodies to a pathogenic mycoplasma in American alligators (Alligator mississippiensis), broad-nosed Caimans (Caiman latirostris), and Siamese crocodiles (Crocodylus siamensis).

    PubMed

    Brown, D R; Schumacher, I M; Nogueira, M F; Richey, L J; Zacher, L A; Schoeb, T R; Vliet, K A; Bennett, R A; Jacobson, E R; Brown, M B

    2001-01-01

    An epidemic of pneumonia with fibrinous polyserositis and multifocal arthritis emerged in captive American alligators (Alligator mississippiensis) in Florida, United States, in 1995. Mycoplasma alligatoris sp. nov. was cultured from multiple organs, peripheral blood, synovial fluid, and cerebrospinal fluid of affected alligators. In a subsequent experimental inoculation study, the Henle-Koch-Evans postulates were fulfilled for M. alligatoris as the etiological agent of fatal mycoplasmosis of alligators. That finding was remarkable because mycoplasmal disease is rarely fatal in animals. An enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies produced by alligators in response to M. alligatoris exposure was developed by using plasma obtained from naturally infected alligators during the original epidemic. The assay was validated by using plasma obtained during an experimental dose-response study and applied to analyze plasma obtained from captive and wild crocodilian species. The ELISA reliably detected alligator seroconversion (P < 0.05) beginning 6 weeks after inoculation. The ELISA also detected seroconversion (P < 0.05) in the relatively closely related broad-nosed caiman Caiman latirostris and the relatively distantly related Siamese crocodile Crocodylus siamensis following experimental inoculation with M. alligatoris. The ELISA may be used to monitor exposure to the lethal pathogen M. alligatoris among captive, repatriated, and wild crocodilian species.

  12. 78 FR 44961 - Endangered Species; Marine Mammals; Receipt of Applications for Permit

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-25

    ... (Podocnemis unifilis) Spotted pond turtle (Geoclemys hamiltonii) Nile crocodile (Crocodylus niloticus) Saltwater crocodile (Crocodylus porosus) Caiman (Caiman crocodilus) Indian python (Python molurus molurus... rhombifer), saltwater crocodile (Crocodylus porosus), yacare caiman (Caiman yacare), caiman...

  13. Eustrongylides sp. (Nematoda: Dioctophymatoidea) from the stomach of a Nile crocodile, Crocodylus niloticus Laurenti, 1768, in Botswana.

    PubMed

    Junker, K; Bain, O; Boomker, J

    2006-12-01

    During a study conducted between 2003 and 2005 on the diet of Nile crocodiles in Botswana, two young adult nematodes, one male and one female, belonging to the genus Eustrongylides Jägerskiöld, 1909 were recovered from the stomach contents of one of these animals. The caudal bursa of the male is present and the ejaculatory duct could be identified, but the spicule could not be seen. The vulva of the female has opened and the anus is situated on a terminal protruberance. Measurements and drawings of these specimens are provided, together with some data on the occurrence and life-cycles of members of the genus Eustrongylides in crocodilians world-wide and in African hosts in particular. Piscivorous birds are the usual final hosts of these nematodes. It is probable that the specimens described herein had developed in a paratenic fish host, and that the latter had been eaten by the crocodile.

  14. Hepatic and renal concentrations of 10 trace elements in crocodiles (Crocodylus niloticus) in the Kafue and Luangwa rivers in Zambia.

    PubMed

    Almli, Bjørn; Mwase, Maxwell; Sivertsen, Tore; Musonda, Mike M; Flåøyen, Arne

    2005-01-20

    Hepatic and renal concentrations of the elements arsenic, cadmium, cobalt, copper, lead, manganese, mercury, molybdenum, selenium and zinc were determined in samples collected from four crocodiles from the Kafue River, Kafue National Park and five crocodiles from the Luangwa River, Luangwa National Park, Zambia. The concentrations of the essential elements were similar to those reported in other vertebrates. Arsenic and cadmium concentrations were low (medians below 0.05 microg As/g and below 0.16 microg Cd/g, wet wt.). Mercury and lead concentrations were several orders of magnitude higher (medians up to 3.7 microg Hg/g, and up to 8.7 microg Pb/g, all wet wt.) than in hippopotami from the same rivers, probably as a result of food-chain biomagnification. Judging by the results obtained in this study, pollution from the mining activity around the Kafue River drainage area in the Copperbelt region has not significantly influenced the trace element concentrations in tissues of the crocodiles in the Kafue National Park. The trace element concentrations measured may serve as reference values in future studies on crocodilians.

  15. Trichinella zimbabwensis n.sp. (Nematoda), a new non-encapsulated species from crocodiles (Crocodylus niloticus) in Zimbabwe also infecting mammals.

    PubMed

    Pozio, E; Foggin, C M; Marucci, G; La Rosa, G; Sacchi, L; Corona, S; Rossi, P; Mukaratirwa, S

    2002-12-19

    Since 1995, Trichinella larvae have been detected in 39.5% of farmed crocodiles (Crocodylus niloticus) in Zimbabwe. Morphological, biological, biochemical and molecular studies carried out on one isolate from a farmed crocodile in 2001 support the conclusion that this parasite belongs to a new species, which has been named Trichinella zimbabwensis n.sp. This species, whose larvae are non-encapsulated in host muscles, infects both reptiles and mammals. The morphology of adults and larvae is similar to that of Trichinella papuae. Adults of T. zimbabwensis cross in both directions with adults of T. papuae (i.e. male of T. zimbabwensis per female of T. papuae and male of T. papuae per female of T. zimbabwensis), producing F1 offspring which produce very few and less viable F2 larvae. Muscle larvae of T. zimbabwensis, like those of T. papuae, do not infect birds. Three allozymes (of a total of 10) are diagnostic between T. zimbabwensis and T. papuae, and five are diagnostic between T. zimbabwensis and Trichinella pseudospiralis, the third non-encapsulated species. The percentage of the pairwise alignment identity between T. zimbabwensis and the other Trichinella species for the cytochrome oxidase subunit I gene, the large subunit ribosomal-DNA (mt-lsrDNA) gene and the expansion segment five, shows that T. zimbabwensis is more similar to the two non-encapsulated species T. papuae (91% for cytochrome oxidase I; 96% for mt-lsrDNA; and 88% for expansion segment five) and T. pseudospiralis (88% for cytochrome oxidase I; 90% for mt-lsrDNA; and 66-73% for expansion segment five) than to any of the encapsulated species (85-86% for cytochrome oxidase I; 88-89% for mt-lsrDNA; and 71-79% for expansion segment five). This is the first non-encapsulated species discovered in Africa. The finding of a new Trichinella species that infects both reptiles and mammals suggests that the origin of Trichinella parasites dates back further than previously believed and can contribute to

  16. Proton leak in hepatocytes and liver mitochondria from archosaurs (crocodiles) and allometric relationships for ectotherms.

    PubMed

    Hulbert, A J; Else, P L; Manolis, S C; Brand, M D

    2002-07-01

    It has previously been shown that mitochondrial proton conductance decreases with increasing body mass in mammals and is lower in a 250-g lizard than the laboratory rat. To examine whether mitochondrial proton conductance is extremely low in very large reptiles, hepatocytes and mitochondria were prepared from saltwater crocodiles ( Crocodylus porosus) and freshwater crocodiles ( Crocodylus johnstoni). Respiration rates of hepatocytes and liver mitochondria were measured at 37 degrees C and compared with values obtained for rat or previously measured for other species. Respiration rates of hepatocytes from either species of crocodile were similar to those reported for lizards and approximately one fifth of the rates measured using cells from mammals (rat and sheep). Ten-to-thirty percent of crocodile hepatocyte respiration was used to drive mitochondrial proton leak, similar to the proportion in other species. Respiration rates of crocodile liver mitochondria were similar to those of mammalian species. Proton leak rate in isolated liver mitochondria was measured as a function of membrane potential. Contrary to our prediction, the mitochondrial proton conductance of liver mitochondria from crocodiles was greater than that of liver mitochondria from lizards and was similar to that of rats. The acyl composition of liver mitochondrial phospholipids from the crocodiles was more similar to that in mitochondria from rats than in mitochondria from lizards. The relatively high mitochondrial proton conductance was associated with a relatively small liver, which seems to be characteristic of crocodilians. Comparison of data from a number of diverse ectothermic species suggested that hepatocyte respiration rate may decrease with body mass, with an allometric exponent of about -0.2, similar to the exponent in mammalian hepatocytes. However, unlike mammals, liver mitochondrial proton conductance in ectotherms showed no allometric relationship with body size.

  17. Molecular cloning and expression of α-globin and β-globin genes from crocodile (Crocodylus siamensis).

    PubMed

    Anwised, Preeyanan; Kabbua, Thai; Temsiripong, Theeranan; Dhiravisit, Apisak; Jitrapakdee, Sarawut; Araki, Tomohiro; Yoneda, Kazunari; Thammasirirak, Sompong

    2013-03-01

    The first report of complete nucleotide sequences for α- and β-globin chains from the Siamese hemoglobin (Crocodylus siamensis) is given in this study. The cDNAs encoding α- and β-globins were cloned by RT-PCR using the degenerate primers and by the rapid amplification of cDNA ends method. The full-length α-globin cDNA contains an open reading frame of 423 nucleotides encoding 141 amino acid residues, whereas the β-globin cDNA contains an open reading frame of 438 nucleotides encoding 146 amino acid residues. The authenticity of both α- and β-globin cDNA clones were also confirmed by the heterologous expression in Escherichia coli (E. coli). This is the first time that the recombinant C. siamensis globins were produced in prokaryotic system. Additionally, the heme group was inserted into the recombinant proteins and purified heme-bound proteins were performed by affinity chromatography using Co(2+)-charged Talon resins. The heme-bound proteins appeared to have a maximum absorbance at 415 nm, indicated that the recombinant proteins bound to oxygen and formed active oxyhemoglobin (HbO2). The results indicated that recombinant C. siamensis globins were successfully expressed in prokaryotic system and possessed an activity as ligand binding protein.

  18. Assessment of selected biochemical parameters and humoral immune response of Nile crocodiles (Crocodylus niloticus) experimentally infected with Trichinella zimbabwensis.

    PubMed

    La Grange, Louis J; Mukaratirwa, Samson

    2014-08-21

    Fifteen crocodiles were randomly divided into three groups of five animals. They represented high-infection, medium-infection and low-infection groups of 642 larvae/kg, 414 larvae/kg and 134 larvae/kg bodyweight, respectively. The parameters assessed were blood glucose, creatine phosphokinase (CPK), lactate dehydrogenase (LDH), aspartate transaminase (AST) and alanine transaminase (ALT). The humoral immune response to Trichinella zimbabwensis infection was evaluated in all three groups by an indirect ELISA method. The results showed deviations from normal parameters of blood glucose, CPK, LDH, AST and ALT when compared with reported levels in uninfected reptiles. Contrary to studies involving mammals, hypoglycaemia was not observed in the infected groups in this study. Peak values of blood glucose were reached on post-infection (PI) Day 49, Day 42 and Day 35 in the high-infection, medium-infection and low-infection groups, respectively. Peak values of LDH and AST were observed on PI Day 56, Day 49 and Day 42 in the high-infection, medium-infection and low-infection groups, respectively. Peak values of CPK were observed on Day 35 PI in all three groups. Peak ALT values were reached on Day 56 in the high-infection group and on Day 28 PI in both the medium-infection and low-infection groups. No correlations between the biochemical parameters and infection intensity were observed. Peak antibody titres were reached on Day 49 PI in the medium-infection group, and on Day 42 PI in both the high-infection and low-infection groups. Infection intensity could not be correlated with the magnitude of the humoral immune response or time to sero-conversion. Results from this study were in agreement with results reported in mammals infected with other Trichinella species and showed that antibody titres could not be detected indefinitely.

  19. IgH loci of American alligator and saltwater crocodile shed light on IgA evolution.

    PubMed

    Magadán-Mompó, Susana; Sánchez-Espinel, Christian; Gambón-Deza, Francisco

    2013-07-01

    Immunoglobulin loci of two representatives of the order Crocodylia were studied from full genome sequences. Both Alligator mississippiensis and Crocodylus porosus have 13 genes for the heavy chain constant regions of immunoglobulins. The IGHC locus contains genes encoding four immunoglobulins M (IgM), one immunoglobulin D (IgD), three immunoglobulins A (IgA), three immunoglobulins Y (IgY), and two immunoglobulins D2 (IgD2). IgA and IgD2 genes were found in reverse transcriptional orientation compared to the other Ig genes. The IGHD gene contains 11 exons, four of which containing stop codons or sequence alterations. As described in other reptiles, the IgD2 is a chimeric Ig with IgA- and IgD-related domains. This work clarifies the origin of bird IgA and its evolutionary relationship with amphibian immunoglobulin X (IgX) as well as their links with mammalian IgA.

  20. Nuclear microprobe analysis of lead profile in crocodile bones

    NASA Astrophysics Data System (ADS)

    Orlic, I.; Siegele, R.; Hammerton, K.; Jeffree, R. A.; Cohen, D. D.

    2003-09-01

    Elevated concentrations of lead were found in Australian free ranging saltwater crocodile ( Crocodylus porosus) bone and flesh. Lead shots were found as potential source of lead in these animals. ANSTO's heavy ion nuclear microprobe was used to measure the distribution of Pb in a number of bones and osteoderms. The aim was to find out if elevated Pb concentration remains in growth rings and if the concentration is correlated with the blood levels recorded at the time. Results of our study show a very distinct distribution of accumulated Pb in bones and osteoderms as well as good correlation with the level of lead concentration in blood. To investigate influence of ion species on detection limits measurements of the same sample were performed by using 3 MeV protons, 9 MeV He ions and 20 MeV carbon ions. Peak to background ratios, detection limits and the overall 'quality' of obtained spectra are compared and discussed.

  1. Development and application of an indirect ELISA test for the detection of antibodies to Mycoplasma crocodyli infection in crocodiles (Crocodylus niloticus).

    PubMed

    Dawo, Fufa; Mohan, Krishna

    2007-01-31

    Non-availability of a standardized rapid serodiagnostic test for quick and accurate diagnosis of Mycoplasma crocodyli (M. crocodyli) infection in crocodiles was the underlining reason for conducting the present study. An indirect enzyme-linked immunosorbent assay (iELISA) for the detection of antibodies (Ab) to M. crocodyli infection in crocodile sera was developed using sonicated antigen (Ag) and anti-crocodile conjugate. The iELISA test was optimised with different reagents and at different steps. A cut-off value of percent positive greater than or equal to 53.47% resulted in an estimated sensitivity and specificity of 85.67 and 100%, respectively. The developed iELISA could be used for detection of Abs to M. crocodyli infection in crocodiles and may enable to understand the transmission of the disease.

  2. Necrotizing fasciitis in captive juvenile Crocodylus porosus caused by Streptococcus agalactiae: an outbreak and review of the animal and human literature.

    PubMed

    Bishop, E J; Shilton, C; Benedict, S; Kong, F; Gilbert, G L; Gal, D; Godoy, D; Spratt, B G; Currie, B J

    2007-11-01

    We observed an outbreak of necrotizing fasciitis associated with Streptococcus agalactiae infection in a group of juvenile saltwater crocodiles (Crocodylus porosus). We undertook screening of crocodiles and the environment to clarify the source of the outbreak and evaluated the isolates cultured from post-mortem specimens with molecular methods to assess clonality and the presence of known group B streptococcal virulence determinants. The isolates were indistinguishable by pulsed-field gel electrophoresis. They were a typical serotype Ia strain with the Calpha-like protein gene, epsilon (or alp1), the mobile genetic elements IS381 ISSag1 and ISSag2, and belonged to multi-locus sequence type (ST) 23. All of these characteristics suggest they were probably of human origin. We review the medical and veterinary literature relating to S. agalactiae necrotizing fasciitis, epidemiology and virulence determinants.

  3. Assessment of microsatellites in estimating inter- and intraspecific variation among Neotropical Crocodylus species.

    PubMed

    Bashyal, A; Gross, B A; Venegas-Anaya, M; Lowrance, F; Densmore Iii, L D

    2014-07-25

    We tested microsatellites that were developed for the saltwater crocodile (Crocodylus porosus) for cross-species amplification and to provide an estimate of inter- and intraspecific variation among four species of Neotropical crocodiles (C. rhombifer, C. intermedius, C. acutus, and C. moreletii). Our results indicated that with the exception of 2 loci in C. intermedius, all 10 microsatellite loci were successfully amplified in the 4 species, producing a set of variably sized alleles that ranged in number between 2 and 14 alleles per locus. Similarly, private alleles (i.e., unique alleles) also were reported in all 4 species for at least 3 loci. The mean observed and expected heterozygosities (averaged across species for all 10 loci combined) ranged from 0.39 to 0.77 and from 0.44 to 0.78, respectively. In addition to this, we evaluated these microsatellites in 2 populations of C. acutus and C. moreletii to assess their utility in estimating intraspecific levels of polymorphisms. These microsatellites also showed considerable allelic variation in population level analysis. The set of 10 microsatellite loci in our study had the potential to be used as a tool in population and conservation genetic studies of Neotropical crocodiles.

  4. Evidence for Wild Crocodiles as a Risk for Human Leptospirosis, Mexico.

    PubMed

    Pérez-Flores, Jonathan; Charruau, Pierre; Cedeño-Vázquez, Rogelio; Atilano, Daniel

    2017-03-01

    Sentinel species such as crocodilians are used to monitor the health of ecosystems. However, few studies have documented the presence of zoonotic diseases in wild populations of these reptiles. Herein we analyzed 48 serum samples from Crocodylus acutus (n = 34) and C. moreletii (n = 14) from different sites in the state of Quintana Roo (Mexico) to detect antibodies to Leptospira interrogans by means of a microscopic agglutination test (MAT). Crocodylus acutus and C. moreletii tested positive to 11 and 9 serovars, respectively, with Grippotyphosa being the serovar with the highest prevalence in Cozumel island (100%), Banco Chinchorro Biosphere Reserve (70.6%), and Río Hondo (100%), while in Chichankanab Lake, it was Bratislava (75%). Titers ranged from 1:50 to 1:3200, and the most frequent was 1:50 in all study sites. Leptospira is present in fresh and saltwater individuals due to the resistance of the bacterium in both environments. Cases of infected people involved with crocodile handling and egg collection suggest that these reptiles could play an important role in the transmission of leptospirosis. Preventive medicine programs should consider the monitoring of reptiles, and testing the soil and water, to prevent outbreaks of leptospirosis in facilities containing crocodiles.

  5. Comparison of biochemical stress indicators in juvenile captive estuarine crocodiles (Crocodylus porosus) following physical restraint or chemical restraint by midazolam injection.

    PubMed

    Olsson, Annabelle; Phalen, David

    2013-07-01

    Using a prospective, randomized study design we demonstrate that midazolam sedation minimizes acidosis compared with physical restraint in captive juvenile estuarine crocodiles during handling or noninvasive procedures at preferred body temperature. A dose of midazolam (5.0 mg/kg) was administered intramuscularly into the forelimb of 20 male estuarine crocodiles weighing 2-3.5 kg. Their heart and respiratory rate and degree of sedation were monitored until recovery and then daily for 7 subsequent days. Blood samples were taken at 30, 60, 90, 180, and 360 min. We recorded lactate, partial pressure of carbon dioxide (CO2), hematocrit, glucose, and blood pH. A second group (1.9-2.6 kg) was physically restrained for 5 min and the same parameters recorded. Physically restrained animals demonstrated elevated heart rate, respiratory rate, glucose, lactate, and anion gap compared with the midazolam-treated group. Physically restrained animals had lower pH, bicarbonate, and partial pressure of CO2 compared with the midazolam-treated group. Behavior in the physically restrained group in the days following the study was disrupted, with reluctance to feed and bask, compared with midazolam-treated animals whose behavior was normal. We conclude that midazolam administered in the forelimb of captive estuarine crocodiles of 2-3.5 kg provides predictable onset and duration of sedation enabling physical examination, sample collection, and translocation of the animals with minimal disturbance to lactate, pH, and CO2. Behavior following recovery appears normal.

  6. Identification of Indian crocodile species through DNA barcodes.

    PubMed

    Meganathan, P R; Dubey, Bhawna; Jogayya, Kothakota Naga; Haque, Ikramul

    2013-07-01

    The biodiversity of India includes three crocodile species, Crocodylus palustris, Crocodylus porosus, and Gavialis gangeticus, whose status is threatened due to bushmeat crisis and illegal hunting. The crocodilian conservation management requires novel techniques to help forensic analysts to reveal species identity. DNA barcoding is a species identification technique, where a partial cytochrome c oxidase subunit 1 gene is used as a marker for species identification. Herein, the DNA barcoding technique is evaluated for three Indian crocodiles by analyzing an approximately 750-bp barcode region. The alignment result shows interspecific variations between sequences for discrimination of the three Indian crocodiles leading to species identification. The phylogenetic analyses also substantiate the established crocodilian relationships, which add further advantage to use this DNA barcoding approach for Indian crocodiles. This study provides preliminary evidences for the use of DNA barcoding technique in the identification of Indian crocodile species.

  7. Leiperia cincinnalis Sambon, 1922 (Pentastomida) from Nile crocodiles Crocodylus niloticus in the Kruger National Park, South Africa, with a description of the male.

    PubMed

    Junker, K; Boomker, J; Swanepoel, D; Taraschewski, H

    2000-09-01

    A single male and several adult females of the pentastomid Leiperia cincinnalis were recovered from the trachea of five of six Nile crocodiles examined in 1995 and 1998. Infective larvae, pre-adult males and females, as well as mature males, occurred in clusters in the pulmonary artery but infective larvae and pre-adult females were also occasionally taken from the lungs. Irrespective of the developmental stage, the intensity of infection was 3, 6, 48, 72 and 79. Sixty-four percent of eggs recovered from the posterior part of the uterus of a patent L. cincinnalis female contained fully-developed primary larvae and these were used to infect 24 Mozambique bream Oreochromis mossambicus. Within a week of infection all the fish died and hatched primary larvae were recovered from the stomach and anterior part of the intestine. Eggs that had not hatched were found to be unsegmented. The total primary larval count in seven fish was 18, 12, 1, 25, 16, >40 and >50. Descriptions with detailed measurements are given of the females, the males, the eggs, the primary larvae and the infective larvae of L. cincinnalis.

  8. Antibodies to West Nile virus in wild and farmed crocodiles in southeastern Mexico.

    PubMed

    Machain-Williams, Carlos; Padilla-Paz, Sergio E; Weber, Manuel; Cetina-Trejo, Rosa; Juarez-Ordaz, José Alfredo; Loroño-Pino, María Alba; Ulloa, Armando; Wang, Chong; Garcia-Rejon, Julián; Blitvich, Bradley J

    2013-07-01

    Surveillance for evidence of West Nile virus (WNV) infection in Morelet's crocodiles (Crocodylus moreletii) was conducted in Campeche State, Mexico, in 2007. Sera from 62 crocodiles (32 free-ranging and 30 captive) were assayed for antibodies to WNV by epitope-blocking enzyme-linked immunosorbent assay. Antibodies to WNV were detected in 13 (41%) wild and nine (30%) captive crocodiles, and the overall antibody prevalence was 35%. Although evidence of WNV infection in captive crocodiles has been reported in Mexico, we provide the first evidence of WNV exposure in wild crocodiles in Mexico.

  9. 77 FR 49453 - Endangered Species; Receipt of Applications for Permit

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-16

    ... crocodile (Osteolaemus tetraspis) Chinese alligator (Alligator sinensis) Cuban crocodile (Crocodylus rhombifer) Siamese crocodile (Crocodylus siamensis) Morelet's crocodile (Crocodylus moreletii) False...

  10. Characterization of crocodile teeth: correlation of composition, microstructure, and hardness.

    PubMed

    Enax, Joachim; Fabritius, Helge-Otto; Rack, Alexander; Prymak, Oleg; Raabe, Dierk; Epple, Matthias

    2013-11-01

    Structure and composition of teeth of the saltwater crocodile Crocodylus porosus were characterized by several high-resolution analytical techniques. X-ray diffraction in combination with elemental analysis and infrared spectroscopy showed that the mineral phase of the teeth is a carbonated calcium-deficient nanocrystalline hydroxyapatite in all three tooth-constituting tissues: Dentin, enamel, and cementum. The fluoride content in the three tissues is very low (<0.1 wt.%) and comparable to that in human teeth. The mineral content of dentin, enamel, and cementum as determined by thermogravimetry is 71.3, 80.5, and 66.8 wt.%, respectively. Synchrotron X-ray microtomography showed the internal structure and allowed to visualize the degree of mineralization in dentin, enamel, and cementum. Virtual sections through the tooth and scanning electron micrographs showed that the enamel layer is comparably thin (100-200 μm). The crystallites in the enamel are oriented perpendicularly to the tooth surface. At the dentin-enamel-junction, the packing density of crystallites decreases, and the crystallites do not display an ordered structure as in the enamel. The microhardness was 0.60±0.05 GPa for dentin, 3.15±0.15 GPa for enamel, 0.26±0.08 GPa for cementum close to the crown, and 0.31±0.04 GPa for cementum close to the root margin. This can be explained with the different degree of mineralization of the different tissue types and is comparable with human teeth.

  11. Identification of purebred Crocodylus siamensis for reintroduction in Vietnam.

    PubMed

    Fitzsimmons, Nancy Nelson; Buchan, Jason Craig; Lam, Phan Viet; Polet, Gert; Hung, Ton That; Thang, Nguyen Quoc; Gratten, Jacob

    2002-12-15

    Crocodylus siamensis, the Siamese crocodile, is a critically endangered species of freshwater crocodile previously distributed throughout much of SE Asia. Recovery plans call for reintroductions to the wild using founder individuals currently in captivity, mostly in commercial crocodile farms. On many farms C. siamensis has been intentionally hybridised with either Cuban crocodiles, C. rhombifer, or the estuarine crocodile, C. porosus, and hybrids may be difficult to distinguish morphologically. We report on the combined use of microsatellite and mtDNA genetic markers to determine the species status of potential founder individuals for reintroduction of C. siamensis. Genetic markers were used to characterise 103 captive and wild-caught individuals of C. siamensis, C. rhombifer and C. porosus in Vietnam and to distinguish purebred versus hybrid individuals. Although the microsatellite loci used had some overlap of allele sizes among species, assignment tests allowed differentiation. Four hybrids were identified, two of which had not been recognised morphologically as hybrids, and one of these was thought to be a C. siamensis suitable for reintroduction. Ten of the identified purebred C. siamensis were subsequently released into Cat Tien National Park in southern Vietnam.

  12. Molecular identification of Indian crocodile species: PCR-RFLP method for forensic authentication*.

    PubMed

    Meganathan, P R; Dubey, Bhawna; Haque, Ikramul

    2009-09-01

    South East Asian countries are known for illegal poaching and trade of crocodiles clandestinely, to be used in skin, medicinal, and cosmetic industries. Besides crocodiles being listed in the Convention on International Trade in Endangered Species of Wild Fauna and Flora, India has its Wildlife Protection Act, 1972 for conservation of crocodile species. Hitherto, lack of any rapid and reliable technique for examinations of crocodile-based crime exhibits such as skin, bones, etc. has been a major problem for an effective promulgation of law on illegal trade. DNA-based identification of species using PCR-RFLP technique for an apt identification of all the three Indian crocodile species namely, Crocodylus porosus, Crocodylus palustris and Gavialis gangeticus is presented here. A 628 bp segment of cytochrome b gene was amplified using novel primers followed by restriction digestion with three enzymes i.e., HaeIII, MboI, and MwoI, separately and in combination. The technique has produced a species-specific pattern for identifying the three crocodile species individually, which fulfills the requirement for its forensic application. It is expected that the technique will prove handy in identification of all the three Indian crocodile species and strengthen conservation efforts.

  13. A time-calibrated species tree of Crocodylia reveals a recent radiation of the true crocodiles.

    PubMed

    Oaks, Jamie R

    2011-11-01

    True crocodiles (Crocodylus) are the most broadly distributed, ecologically diverse, and species-rich crocodylian genus, comprising about half of extant crocodylian diversity and exhibiting a circumtropical distribution. Crocodylus traditionally has been viewed as an ancient group of morphologically conserved species that originated in Africa prior to continental breakup. In this study, these long-held notions about the temporal and geographic origin of Crocodylus are tested using DNA sequence data of 10 loci from 76 individuals representing all 23 crocodylian species. I infer a time-calibrated species tree of all Crocodylia and estimate the spatial pattern of diversification within Crocodylus. For the first time, a fully resolved phylogenetic estimate of all Crocodylia is well-supported. The results overturn traditional views of the evolution of Crocodylus by demonstrating that the true crocodiles are not "living-fossils" that originated in Africa. Rather, Crocodylus originated from an ancestor in the tropics of the Late Miocene Indo-Pacific, and rapidly radiated and dispersed around the globe during a period marked by mass extinctions of fellow crocodylians. The findings also reveal more diversity within the genus than is recognized by current taxonomy.

  14. A New Horned Crocodile from the Plio-Pleistocene Hominid Sites at Olduvai Gorge, Tanzania

    PubMed Central

    Brochu, Christopher A.; Njau, Jackson; Blumenschine, Robert J.; Densmore, Llewellyn D.

    2010-01-01

    Background The fossil record reveals surprising crocodile diversity in the Neogene of Africa, but relationships with their living relatives and the biogeographic origins of the modern African crocodylian fauna are poorly understood. A Plio-Pleistocene crocodile from Olduvai Gorge, Tanzania, represents a new extinct species and shows that high crocodylian diversity in Africa persisted after the Miocene. It had prominent triangular “horns” over the ears and a relatively deep snout, these resemble those of the recently extinct Malagasy crocodile Voay robustus, but the new species lacks features found among osteolaemines and shares derived similarities with living species of Crocodylus. Methodology/Principal Findings The holotype consists of a partial skull and skeleton and was collected on the surface between two tuffs dated to approximately 1.84 million years (Ma), in the same interval near the type localities for the hominids Homo habilis and Australopithecus boisei. It was compared with previously-collected material from Olduvai Gorge referable to the same species. Phylogenetic analysis places the new form within or adjacent to crown Crocodylus. Conclusions/Significance The new crocodile species was the largest predator encountered by our ancestors at Olduvai Gorge, as indicated by hominid specimens preserving crocodile bite marks from these sites. The new species also reinforces the emerging view of high crocodylian diversity throughout the Neogene, and it represents one of the few extinct species referable to crown genus Crocodylus. PMID:20195356

  15. Role of Chromosome Changes in Crocodylus Evolution and Diversity

    PubMed Central

    Thapana, Watcharaporn; Muangmai, Narongrit

    2015-01-01

    The karyotypes of most species of crocodilians were studied using conventional and molecular cytogenetics. These provided an important contribution of chromosomal rearrangements for the evolutionary processes of Crocodylia and Sauropsida (birds and reptiles). The karyotypic features of crocodilians contain small diploid chromosome numbers (30~42), with little interspecific variation of the chromosome arm number (fundamental number) among crocodiles (56~60). This suggested that centric fusion and/or fission events occurred in the lineage, leading to crocodilian evolution and diversity. The chromosome numbers of Alligator, Caiman, Melanosuchus, Paleosuchus, Gavialis, Tomistoma, Mecistops, and Osteolaemus were stable within each genus, whereas those of Crocodylus (crocodylians) varied within the taxa. This agreed with molecular phylogeny that suggested a highly recent radiation of Crocodylus species. Karyotype analysis also suggests the direction of molecular phylogenetic placement among Crocodylus species and their migration from the Indo-Pacific to Africa and The New World. Crocodylus species originated from an ancestor in the Indo-Pacific around 9~16 million years ago (MYA) in the mid-Miocene, with a rapid radiation and dispersion into Africa 8~12 MYA. This was followed by a trans-Atlantic dispersion to the New World between 4~8 MYA in the Pliocene. The chromosomes provided a better understanding of crocodilian evolution and diversity, which will be useful for further study of the genome evolution in Crocodylia. PMID:26865840

  16. Characterization of Serum Phospholipase A2 Activity in Three Diverse Species of West African Crocodiles

    PubMed Central

    Merchant, Mark; Juneau, Kate; Gemillion, Jared; Falconi, Rodolfo; Doucet, Aaron; Shirley, Matthew H.

    2011-01-01

    Secretory phospholipase A2, an enzyme that exhibits substantial immunological activity, was measured in the serum of three species of diverse West African crocodiles. Incubation of different volumes of crocodile serum with bacteria labeled with a fluorescent fatty acid in the sn-2 position of membrane lipids resulted in a volume-dependent liberation of fluorescent probe. Serum from the Nile crocodile (Crocodylus niloticus) exhibited slightly higher activity than that of the slender-snouted crocodile (Mecistops cataphractus) and the African dwarf crocodile (Osteolaemus tetraspis). Product formation was inhibited by BPB, a specific PLA2 inhibitor, confirming that the activity was a direct result of the presence of serum PLA2. Kinetic analysis showed that C. niloticus serum produced product more rapidly than M. cataphractus or O. tetraspis. Serum from all three species exhibited temperature-dependent PLA2 activities but with slightly different thermal profiles. All three crocodilian species showed high levels of activity against eight different species of bacteria. PMID:22110960

  17. An ancient icon reveals new mysteries: mummy DNA resurrects a cryptic species within the Nile crocodile.

    PubMed

    Hekkala, Evon; Shirley, Matthew H; Amato, George; Austin, James D; Charter, Suellen; Thorbjarnarson, John; Vliet, Kent A; Houck, Marlys L; Desalle, Rob; Blum, Michael J

    2011-10-01

    The Nile crocodile (Crocodylus niloticus) is an ancient icon of both cultural and scientific interest. The species is emblematic of the great civilizations of the Nile River valley and serves as a model for international wildlife conservation. Despite its familiarity, a centuries-long dispute over the taxonomic status of the Nile crocodile remains unresolved. This dispute not only confounds our understanding of the origins and biogeography of the 'true crocodiles' of the crown genus Crocodylus, but also complicates conservation and management of this commercially valuable species. We have taken a total evidence approach involving phylogenetic analysis of mitochondrial and nuclear markers, as well as karyotype analysis of chromosome number and structure, to assess the monophyletic status of the Nile crocodile. Samples were collected from throughout Africa, covering all major bioregions. We also utilized specimens from museum collections, including mummified crocodiles from the ancient Egyptian temples at Thebes and the Grottes de Samoun, to reconstruct the genetic profiles of extirpated populations. Our analyses reveal a cryptic evolutionary lineage within the Nile crocodile that elucidates the biogeographic history of the genus and clarifies long-standing arguments over the species' taxonomic identity and conservation status. An examination of crocodile mummy haplotypes indicates that the cryptic lineage corresponds to an earlier description of C. suchus and suggests that both African Crocodylus lineages historically inhabited the Nile River. Recent survey efforts indicate that C. suchus is declining or extirpated throughout much of its distribution. Without proper recognition of this cryptic species, current sustainable use-based management policies for the Nile crocodile may do more harm than good.

  18. Saltwater Wetlands.

    ERIC Educational Resources Information Center

    Naturescope, 1986

    1986-01-01

    Provides information about saltwater wetlands. Contains seven learning activities which deal with "making" a mud snail, plants and animals of mangroves, and the effects of tides on salt marshes. Included are reproducible handouts and worksheets for several of the activities. (TW)

  19. Skin parasitism by Paratrichosoma recurvum in wild American crocodiles and its relation to environmental and biological factors.

    PubMed

    Charruau, Pierre; Pérez-Flores, Jonathan S; Labarre, Didier

    2017-01-24

    Paratrichosma spp. are capillarid worms that parasitize the abdominal skin of crocodiles. They are likely not a threat to crocodiles' health, but they affect the skins' commercial value. No successful treatment exists against this parasite, and present knowledge of its life cycle is limited. Herein we report new information on Paratrichosoma recurvum occurrence in wild American crocodiles Crocodylus acutus from Mexican Caribbean islands and its relation to environmental (water salinity, temperature, climatic events) and biological (body condition) factors. The percentage of parasitized crocodiles (30.3%) is among the highest recorded in wild crocodilian populations. Small (<40.8 cm total length [TL]) and large (>270 cm TL) crocodiles are less parasitized, probably due to the characteristics of their skin or of the parasite life cycle. Two individuals appeared to have eliminated worms naturally between their capture and recapture. The thorax-abdomen is the most parasitized area of the body of crocodiles. The risk of infection is not associated with the sex of the crocodile, but there was a difference in the proportion of parasitized crocodiles between sites, which could be related to different environmental conditions. The body condition of a crocodile does not seem to be affected by the parasite. Climatic events and water temperature show no effect on the parasitism of crocodiles, but salinity could have an effect. The infection of crocodiles by P. recurvum could depend more on an individual's behavior than on environmental conditions.

  20. Are crocodiles really monophyletic?--Evidence for subdivisions from sequence and morphological data.

    PubMed

    McAliley, L Rex; Willis, Ray E; Ray, David A; White, P Scott; Brochu, Christopher A; Densmore, Llewellyn D

    2006-04-01

    Recently, the phylogenetic placement of the African slender snouted crocodile, Crocodylus cataphractus, has come under scrutiny and herein we address this issue using molecular and morphological techniques. Although it is often recognized as being a "basal" form, morphological studies have traditionally placed C. cataphractus within the genus Crocodylus, while molecular studies have suggested that C. cataphractus is very distinct from other Crocodylus. To address the relationship of this species to its congeners we have sequenced portions of two nuclear genes (C-mos 302bp and ODC 294bp), and two mitochondrial genes (ND6-tRNA(glu)-cytB 347bp and control region 457bp). Analyses of these molecular datasets, both as individual gene sequences and as concatenated sequences, support the hypothesis that C. cataphractus is not a member of Crocodylus or Osteolaemus. Examination of 165 morphological characters supports and strengthens our resurrection of an historic genus, Mecistops (Gray 1844) for cataphractus.

  1. Public health risks of the flesh of farmed crocodiles.

    PubMed

    Millan, J M; Purdie, J L; Melville, L F

    1997-08-01

    The farming of crocodiles in the Northern Territory of Australia is a rapidly growing industry. The saltwater crocodile produces a premium quality skin which is sought world-wide for the lucrative leather trade and manufacture of finished articles. Flesh is considered to be a by-product of skin production. Several procedures are used in abattoirs to prevent the risk of cross contamination of flesh. The public health risks linked to the production of crocodile flesh are described for the two main diseases of concern, namely: sparganosis and salmonellosis. The slaughter and hygienic processing procedures and local laboratory evidence indicate that the consumption of crocodile flesh produced in the Northern Territory carries a negligible public health risk.

  2. Determinants of habitat selection by hatchling Australian freshwater crocodiles.

    PubMed

    Somaweera, Ruchira; Webb, Jonathan K; Shine, Richard

    2011-01-01

    Animals almost always use habitats non-randomly, but the costs and benefits of using specific habitat types remain unknown for many types of organisms. In a large lake in northwestern Australia (Lake Argyle), most hatchling (<12-month-old) freshwater crocodiles (Crocodylus johnstoni) are found in floating vegetation mats or grassy banks rather than the more widely available open banks. Mean body sizes of young crocodiles did not differ among the three habitat types. We tested four potential explanations for non-random habitat selection: proximity to nesting sites, thermal conditions, food availability, and exposure to predation. The three alternative habitat types did not differ in proximity to nesting sites, or in thermal conditions. Habitats with higher food availability harboured more hatchlings, and feeding rates (obtained by stomach-flushing of recently-captured crocodiles) were highest in such areas. Predation risk may also differ among habitats: we were twice as likely to capture a crocodile after seeing it in open-bank sites than in the other two habitat types. Thus, habitat selection of hatchling crocodiles in this system may be driven both by prey availability and by predation risk.

  3. Determinants of Habitat Selection by Hatchling Australian Freshwater Crocodiles

    PubMed Central

    Somaweera, Ruchira; Webb, Jonathan K.; Shine, Richard

    2011-01-01

    Animals almost always use habitats non-randomly, but the costs and benefits of using specific habitat types remain unknown for many types of organisms. In a large lake in northwestern Australia (Lake Argyle), most hatchling (<12-month-old) freshwater crocodiles (Crocodylus johnstoni) are found in floating vegetation mats or grassy banks rather than the more widely available open banks. Mean body sizes of young crocodiles did not differ among the three habitat types. We tested four potential explanations for non-random habitat selection: proximity to nesting sites, thermal conditions, food availability, and exposure to predation. The three alternative habitat types did not differ in proximity to nesting sites, or in thermal conditions. Habitats with higher food availability harboured more hatchlings, and feeding rates (obtained by stomach-flushing of recently-captured crocodiles) were highest in such areas. Predation risk may also differ among habitats: we were twice as likely to capture a crocodile after seeing it in open-bank sites than in the other two habitat types. Thus, habitat selection of hatchling crocodiles in this system may be driven both by prey availability and by predation risk. PMID:22163308

  4. Validation of a multiplex PCR assay for the forensic identification of Indian crocodiles.

    PubMed

    Meganathan, Poorlin Ramakodi; Dubey, Bhawna; Jogayya, Kothakota Naga; Haque, Ikramul

    2011-09-01

    A dependable and efficient wildlife species identification system is essential for swift dispensation of the justice linking wildlife crimes. Development of molecular techniques is befitting the need of the time. The forensic laboratories often receive highly ill-treated samples for identification purposes, and thus, validation of any novel methodology is necessary for forensic usage. We validate a novel multiplex polymerase chain reaction assay, developed at this laboratory for the forensic identification of three Indian crocodiles, Crocodylus palustris, Crocodylus porosus, and Gavialis gangeticus, following the guidelines of Scientific Working Group on DNA Analysis Methods. The multiplex PCR was tested for its specificity, reproducibility, sensitivity, and stability. This study also includes the samples treated with various chemical substances and exposed to various environmental regimes. The result of this validation study promises this technique to be an efficient identification tool for Indian crocodiles and therefore is recommended for forensic purposes.

  5. Integrating molecular, phenotypic and environmental data to elucidate patterns of crocodile hybridization in Belize.

    PubMed

    Hekkala, Evon R; Platt, Steven G; Thorbjarnarson, John B; Rainwater, Thomas R; Tessler, Michael; Cunningham, Seth W; Twomey, Christopher; Amato, George

    2015-09-01

    The genus Crocodylus comprises 12 currently recognized species, many of which can be difficult to differentiate phenotypically. Interspecific hybridization among crocodiles is known to occur in captivity and has been documented between some species in the wild. The identification of hybrid individuals is of importance for management and monitoring of crocodilians, many of which are Convention on International Trade in Endangered Species (CITES) listed. In this study, both mitochondrial and nuclear DNA markers were evaluated for their use in confirming a suspected hybrid zone between American crocodile (Crocodylus acutus) and Morelet's crocodile (Crocodylus moreletii) populations in southern Belize where individuals and nests exhibiting atypical phenotypic features had previously been observed. Patterns observed in both phenotypic and molecular data indicate possible behavioural and ecological characteristics associated with hybridization events. The results of the combined analyses found that the majority of suspected hybrid samples represent crosses between female C. acutus and male C. moreletii. Phenotypic data could statistically identify hybrids, although morphological overlap between hybrids and C. moreletii reduced reliability of identification based solely on field characters. Ecologically, C. acutus was exclusively found in saline waters, whereas hybrids and C. moreletii were largely absent in these conditions. A hypothesized correlation between unidirectional hybridization and destruction of C. acutus breeding habitats warrants additional research.

  6. Integrating molecular, phenotypic and environmental data to elucidate patterns of crocodile hybridization in Belize

    PubMed Central

    Hekkala, Evon R.; Platt, Steven G.; Thorbjarnarson, John B.; Rainwater, Thomas R.; Tessler, Michael; Cunningham, Seth W.; Twomey, Christopher; Amato, George

    2015-01-01

    The genus Crocodylus comprises 12 currently recognized species, many of which can be difficult to differentiate phenotypically. Interspecific hybridization among crocodiles is known to occur in captivity and has been documented between some species in the wild. The identification of hybrid individuals is of importance for management and monitoring of crocodilians, many of which are Convention on International Trade in Endangered Species (CITES) listed. In this study, both mitochondrial and nuclear DNA markers were evaluated for their use in confirming a suspected hybrid zone between American crocodile (Crocodylus acutus) and Morelet’s crocodile (Crocodylus moreletii) populations in southern Belize where individuals and nests exhibiting atypical phenotypic features had previously been observed. Patterns observed in both phenotypic and molecular data indicate possible behavioural and ecological characteristics associated with hybridization events. The results of the combined analyses found that the majority of suspected hybrid samples represent crosses between female C. acutus and male C. moreletii. Phenotypic data could statistically identify hybrids, although morphological overlap between hybrids and C. moreletii reduced reliability of identification based solely on field characters. Ecologically, C. acutus was exclusively found in saline waters, whereas hybrids and C. moreletii were largely absent in these conditions. A hypothesized correlation between unidirectional hybridization and destruction of C. acutus breeding habitats warrants additional research. PMID:26473062

  7. The probable role of cannibalism in spreading Trichinella papuae infection in a crocodile farm in Papua New Guinea.

    PubMed

    Owen, Ifor L; Awui, Columba; Langelet, Eric; Soctine, Wenda; Reid, Simon

    2014-07-14

    Between 2003 and 2007, 83 (50%) of 167 crocodiles (Crocodylus porosus) purchased as juveniles by a crocodile farm 3 or 4 years earlier from Kikori, Gulf Province, were found to be infected with Trichinella papuae. Between 2005 and 2007 infection was detected in a number of crocodiles at the farm obtained from six localities other than Kikori, as well as in a few animals born on the farm. Up to 2004, all juveniles at the farm, whether wild- or farm-born, were penned together; the practice was then stopped to prevent possible infection through cannibalism. The last infected animal from Kikori was seen in 2007, 4 years after the purchase of crocodiles from there ceased. The last non-Kikori infected crocodile was seen, also, in 2007. None of the 1972 crocodiles (comprising wild- and farm-born animals) tested from 2008 to 2013, using the digestion method, was infected with T. papuae. This indicates that infection of non-Kikori crocodiles was the result of cannibalism within the farm during the years up to 2004 when juvenile crocodiles were kept together, and that the farm is now free of the infection.

  8. HNK-1 immunoreactivity during early morphogenesis of the head region in a nonmodel vertebrate, crocodile embryo.

    PubMed

    Kundrát, Martin

    2008-11-01

    The present study examines HNK-1 immunoidentification of a population of the neural crest (NC) during early head morphogenesis in the nonmodel vertebrate, the crocodile (Crocodylus niloticus) embryos. Although HNK-1 is not an exclusive NC marker among vertebrates, temporospatial immunoreactive patterns found in the crocodile are almost consistent with NC patterns derived from gene expression studies known in birds (the closest living relatives of crocodiles) and mammals. In contrast to birds, the HNK-1 epitope is immunoreactive in NC cells at the neural fold level in crocodile embryos and therefore provides sufficient base to assess early migratory events of the cephalic NC. I found that crocodile NC forms three classic migratory pathways in the head: mandibular, hyoid, and branchial. Further, I demonstrate that, besides this classic phenotype, there is also a forebrain-derived migratory population, which consolidates into a premandibular stream in the crocodile. In contrast to the closely related chick model, crocodilian premandibular and mandibular NC cells arise from the open neural tube suggesting that species-specific heterochronic behavior of NC may be involved in the formation of different vertebrate facial phenotypes.

  9. HNK-1 immunoreactivity during early morphogenesis of the head region in a nonmodel vertebrate, crocodile embryo

    NASA Astrophysics Data System (ADS)

    Kundrát, Martin

    2008-11-01

    The present study examines HNK-1 immunoidentification of a population of the neural crest (NC) during early head morphogenesis in the nonmodel vertebrate, the crocodile ( Crocodylus niloticus) embryos. Although HNK-1 is not an exclusive NC marker among vertebrates, temporospatial immunoreactive patterns found in the crocodile are almost consistent with NC patterns derived from gene expression studies known in birds (the closest living relatives of crocodiles) and mammals. In contrast to birds, the HNK-1 epitope is immunoreactive in NC cells at the neural fold level in crocodile embryos and therefore provides sufficient base to assess early migratory events of the cephalic NC. I found that crocodile NC forms three classic migratory pathways in the head: mandibular, hyoid, and branchial. Further, I demonstrate that, besides this classic phenotype, there is also a forebrain-derived migratory population, which consolidates into a premandibular stream in the crocodile. In contrast to the closely related chick model, crocodilian premandibular and mandibular NC cells arise from the open neural tube suggesting that species-specific heterochronic behavior of NC may be involved in the formation of different vertebrate facial phenotypes.

  10. Spatial and stage-structured population model of the American crocodile for comparison of comprehensive Everglades Restoration Plan (CERP) alternatives

    USGS Publications Warehouse

    Green, Timothy W.; Slone, Daniel H.; Swain, Eric D.; Cherkiss, Michael S.; Lohmann, Melinda; Mazzotti, Frank J.; Rice, Kenneth G.

    2010-01-01

    As part of the U.S. Geological Survey Priority Ecosystems Science (PES) initiative to provide the ecological science required during Everglades restoration, we have integrated current regional hydrologic models with American crocodile (Crocodylus acutus) research and monitoring data to create a model that assesses the potential impact of Comprehensive Everglades Restoration Plan (CERP) efforts on the American crocodile. A list of indicators was created by the Restoration Coordination and Verification (RECOVER) component of CERP to help determine the success of interim restoration goals. The American crocodile was established as an indicator of the ecological condition of mangrove estuaries due to its reliance upon estuarine environments characterized by low salinity and adequate freshwater inflow. To gain a better understanding of the potential impact of CERP restoration efforts on the American crocodile, a spatially explicit crocodile population model has been created that has the ability to simulate the response of crocodiles to various management strategies for the South Florida ecosystem. The crocodile model uses output from the Tides and Inflows in the Mangroves of the Everglades (TIME) model, an application of the Flow and Transport in a Linked Overland/Aquifer Density Dependent System (FTLOADDS) simulator. TIME has the capability to link to the South Florida Water Management Model (SFWMM), which is the primary regional tool used to assess CERP restoration scenarios. A crocodile habitat suitability index and spatial parameter maps that reflect salinity, water depth, habitat, and nesting locations are used as driving functions to construct crocodile finite rate of increase maps under different management scenarios. Local stage-structured models are integrated with a spatial landscape grid to display crocodile movement behavior in response to changing environmental conditions. Restoration efforts are expected to affect salinity levels throughout the habitat of

  11. Mercury in Morelet's crocodile eggs from northern Belize.

    PubMed

    Rainwater, T R; Adair, B M; Platt, S G; Anderson, T A; Cobb, G P; McMurry, S T

    2002-04-01

    Recent studies have examined mercury accumulation in crocodilians. However, though most researchers have focused on tissue concentrations, few have examined mercury levels in crocodilian eggs. In July 1995, we analyzed mercury in 31 nonviable Morelet's crocodile ( Crocodylus moreletii) eggs collected from eight nests across three localities in northern Belize. All eggs were found to contain mercury. Based on an individual egg basis, mean concentration of mercury for all three localities was among the lowest reported for any crocodilian species. When localities were examined separately, mean concentrations for Laguna Seca and Gold Button Lagoon were comparable to those observed in other studies, and the mean for Sapote Lagoon was the lowest ever reported. Based on mean nest concentrations, mercury in eggs from Laguna Seca was approximately two- and tenfold higher than for Gold Button Lagoon and Sapote Lagoon, respectively. Variability in mercury concentrations among localities is likely the result of site-specific differences in mercury input, bioavailabilty, and bioaccumulation. Mercury concentrations were relatively uniform in eggs from the same nest and among nests from the same localities. The presence of mercury in Morelet's crocodile eggs suggests exposure in adult females, developing embryos, and neonates. However, crocodiles in these areas show no overt signs of mercury toxicity, and no indication of population decline is evident. A paucity of data on the effects of mercury on crocodilians precludes meaningful speculation as to the biological significance of tissue and egg concentrations. Controlled laboratory studies and long-term population monitoring are needed to address these questions.

  12. Evaluating effects of Everglades restoration on American crocodile populations in south Florida using a spatially-explicit, stage-based population model

    USGS Publications Warehouse

    Green, Timothy W.; Slone, Daniel H.; Swain, Eric D.; Cherkiss, Michael S.; Lohmann, Melinda; Mazzotti, Frank J.; Rice, Kenneth G.

    2014-01-01

    The distribution and abundance of the American crocodile (Crocodylus acutus) in the Florida Everglades is dependent on the timing, amount, and location of freshwater flow. One of the goals of the Comprehensive Everglades Restoration Plan (CERP) is to restore historic freshwater flows to American crocodile habitat throughout the Everglades. To predict the impacts on the crocodile population from planned restoration activities, we created a stage-based spatially explicit crocodile population model that incorporated regional hydrology models and American crocodile research and monitoring data. Growth and survival were influenced by salinity, water depth, and density-dependent interactions. A stage-structured spatial model was used with discrete spatial convolution to direct crocodiles toward attractive sources where conditions were favorable. The model predicted that CERP would have both positive and negative impacts on American crocodile growth, survival, and distribution. Overall, crocodile populations across south Florida were predicted to decrease approximately 3 % with the implementation of CERP compared to future conditions without restoration, but local increases up to 30 % occurred in the Joe Bay area near Taylor Slough, and local decreases up to 30 % occurred in the vicinity of Buttonwood Canal due to changes in salinity and freshwater flows.

  13. Sequencing three crocodilian genomes to illuminate the evolution of archosaurs and amniotes.

    PubMed

    St John, John A; Braun, Edward L; Isberg, Sally R; Miles, Lee G; Chong, Amanda Y; Gongora, Jaime; Dalzell, Pauline; Moran, Christopher; Bed'hom, Bertrand; Abzhanov, Arkhat; Burgess, Shane C; Cooksey, Amanda M; Castoe, Todd A; Crawford, Nicholas G; Densmore, Llewellyn D; Drew, Jennifer C; Edwards, Scott V; Faircloth, Brant C; Fujita, Matthew K; Greenwold, Matthew J; Hoffmann, Federico G; Howard, Jonathan M; Iguchi, Taisen; Janes, Daniel E; Khan, Shahid Yar; Kohno, Satomi; de Koning, Ap Jason; Lance, Stacey L; McCarthy, Fiona M; McCormack, John E; Merchant, Mark E; Peterson, Daniel G; Pollock, David D; Pourmand, Nader; Raney, Brian J; Roessler, Kyria A; Sanford, Jeremy R; Sawyer, Roger H; Schmidt, Carl J; Triplett, Eric W; Tuberville, Tracey D; Venegas-Anaya, Miryam; Howard, Jason T; Jarvis, Erich D; Guillette, Louis J; Glenn, Travis C; Green, Richard E; Ray, David A

    2012-01-31

    The International Crocodilian Genomes Working Group (ICGWG) will sequence and assemble the American alligator (Alligator mississippiensis), saltwater crocodile (Crocodylus porosus) and Indian gharial (Gavialis gangeticus) genomes. The status of these projects and our planned analyses are described.

  14. Sequencing three crocodilian genomes to illuminate the evolution of archosaurs and amniotes

    PubMed Central

    2012-01-01

    The International Crocodilian Genomes Working Group (ICGWG) will sequence and assemble the American alligator (Alligator mississippiensis), saltwater crocodile (Crocodylus porosus) and Indian gharial (Gavialis gangeticus) genomes. The status of these projects and our planned analyses are described. PMID:22293439

  15. Crocodiles in the Sahara Desert: An Update of Distribution, Habitats and Population Status for Conservation Planning in Mauritania

    PubMed Central

    Brito, José C.; Martínez-Freiría, Fernando; Sierra, Pablo; Sillero, Neftalí; Tarroso, Pedro

    2011-01-01

    Background Relict populations of Crocodylus niloticus persist in Chad, Egypt and Mauritania. Although crocodiles were widespread throughout the Sahara until the early 20th century, increased aridity combined with human persecution led to local extinction. Knowledge on distribution, occupied habitats, population size and prey availability is scarce in most populations. This study evaluates the status of Saharan crocodiles and provides new data for Mauritania to assist conservation planning. Methodology/Principal Findings A series of surveys in Mauritania detected crocodile presence in 78 localities dispersed across 10 river basins and most tended to be isolated within river basins. Permanent gueltas and seasonal tâmoûrts were the most common occupied habitats. Crocodile encounters ranged from one to more than 20 individuals, but in most localities less than five crocodiles were observed. Larger numbers were observed after the rainy season and during night sampling. Crocodiles were found dead in between water points along dry river-beds suggesting the occurrence of dispersal. Conclusion/Significance Research priorities in Chad and Egypt should focus on quantifying population size and pressures exerted on habitats. The present study increased in by 35% the number of known crocodile localities in Mauritania. Gueltas are crucial for the persistence of mountain populations. Oscillations in water availability throughout the year and the small dimensions of gueltas affect biological traits, including activity and body size. Studies are needed to understand adaptation traits of desert populations. Molecular analyses are needed to quantify genetic variability, population sub-structuring and effective population size, and detect the occurrence of gene flow. Monitoring is needed to detect demographical and genetical trends in completely isolated populations. Crocodiles are apparently vulnerable during dispersal events. Awareness campaigns focusing on the vulnerability and

  16. Nonlinearities in mating sounds of American crocodiles.

    PubMed

    Benko, Tina P; Perc, Matjaz

    2009-09-01

    We use nonlinear time series analysis methods to analyze the dynamics of the sound-producing apparatus of the American crocodile (Crocodylus acutus). We capture its dynamics by analyzing a recording of the singing activity during mating time. First, we reconstruct the phase space from the sound recording and thereby reveal that the attractor needs no less than five degrees of freedom to fully evolve in the embedding space, which suggests that a rather complex nonlinear dynamics underlies its existence. Prior to investigating the dynamics more precisely, we test whether the reconstructed attractor satisfies the notions of determinism and stationarity, as a lack of either of these properties would preclude a meaningful further analysis. After positively establishing determinism and stationarity, we proceed by showing that the maximal Lyapunov exponent of the recording is positive, which is a strong indicator for the chaotic behavior of the system, confirming that dynamical nonlinearities are an integral part of the examined sound-producing apparatus. At the end, we discuss that methods of nonlinear time series analysis could yield instructive insights and foster the understanding of vocal communication among certain reptile species.

  17. Plasma vitellogenin in Morelet's crocodiles from contaminated habitats in northern Belize.

    PubMed

    Rainwater, Thomas R; Selcer, Kyle W; Nespoli, Lisa M; Finger, Adam G; Ray, David A; Platt, Steven G; Smith, Philip N; Densmore, Llewellyn D; Anderson, Todd A; McMurry, Scott T

    2008-05-01

    Vitellogenin induction has been widely used as a biomarker of endocrine disruption in wildlife, but few studies have investigated its use in wild reptiles living in contaminated habitats. This study examined vitellogenin induction in Morelet's crocodiles (Crocodylus moreletii) from wetlands in northern Belize contaminated with organochlorine (OC) pesticides. Vitellogenin was measured in 381 crocodile plasma samples using a vitellogenin ELISA previously developed for this species. Vitellogenin was detected in nine samples, all from adult females sampled during the breeding season. Males and juvenile females did not contain detectable levels of vitellogenin; however, many of these animals contained OC pesticides in their caudal scutes, confirming contaminant exposure. The lack of a vitellogenic response in these animals may be attributable to several factors related to the timing and magnitude of exposure to endocrine-disrupting chemicals and should not be interpreted as an absence of other contaminant-induced biological responses.

  18. Estuarine crocodiles ride surface currents to facilitate long-distance travel.

    PubMed

    Campbell, Hamish A; Watts, Matthew E; Sullivan, Scott; Read, Mark A; Choukroun, Severine; Irwin, Steve R; Franklin, Craig E

    2010-09-01

    1. The estuarine crocodile (Crocodylus porosus) is the world's largest living reptile. It predominately inhabits freshwater and estuarine habitats, but widespread geographic distribution throughout oceanic islands of the South-east Pacific suggests that individuals undertake sizeable ocean voyages. 2. Here we show that adult C. porosus adopt behavioural strategies to utilise surface water currents during long-distance travel, enabling them to move quickly and efficiently over considerable distances. 3. We used acoustic telemetry to monitor crocodile movement throughout 63 km of river, and found that when individuals engaged in a long-distance, constant direction journey (>10 km day(-1)), they would only travel when current flow direction was favourable. Depth and temperature measurements from implanted transmitters showed that they remained at the water surface during travel but would dive to the river substratum or climb out on the river bank if current flow direction became unfavourable. 4. Satellite positional fixes from tagged crocodiles engaged in ocean travel were overlaid with residual surface current (RSC) estimates. The data showed a strong correlation existed between the bearing of the RSC and that of the travelling crocodile (r(2) = 0.92, P < 0.0001). 5. The study demonstrates that C. porosus dramatically increase their travel potential by riding surface currents, providing an effective dispersal strategy for this species.

  19. Fatal crocodile attack.

    PubMed

    Chattopadhyay, Saurabh; Shee, Biplab; Sukul, Biswajit

    2013-11-01

    Attacks on human beings by various animals leading to varied types of injuries and even death in some cases are not uncommon. Crocodile attacks on humans have been reported from a number of countries across the globe. Deaths in such attacks are mostly due to mechanical injuries or drowning. Bites by the crocodiles often cause the limbs to be separated from the body. The present case refers to an incident of a fatal attack by a crocodile on a 35 years old female where only the mutilated head of the female was recovered. Multiple lacerated wounds over the face and scalp along with fracture of the cranial bones was detected on autopsy. Two distinct bite marks in the form of punched in holes were noted over the parietal and frontal bones. Injuries on the head with its traumatic amputation from the body were sufficient to cause death. However, the presence of other fatal injuries on the unrecovered body parts could not be ruled out.

  20. beta-Keratins in crocodiles reveal amino acid homology with avian keratins.

    PubMed

    Ye, Changjiang; Wu, Xiaobing; Yan, Peng; Amato, George

    2010-03-01

    The DNA sequences encoding beta-keratin have been obtained from Marsh Mugger (Crocodylus palustris) and Orinoco Crocodiles (Crocodylus intermedius). Through the deduced amino acid sequence, these proteins are rich in glycine, proline and serine. The central region of the proteins are composed of two beta-folded regions and show a high degree of identity with beta-keratins of aves and squamates. This central part is thought to be the site of polymerization to build the framework of beta-keratin filaments. It is believed that the beta-keratins in reptiles and birds share a common ancestry. Near the C-terminal, these beta-keratins contain a peptide rich in glycine-X and glycine-X-X, and the distinctive feature of the region is some 12-amino acid repeats, which are similar to the 13-amino acid repeats in chick scale keratin but absent from avian feather keratin. From our phylogenetic analysis, the beta-keratins in crocodile have a closer relationship with avian keratins than the other keratins in reptiles.

  1. Interactions between ecology, demography, capture stress, and profiles of corticosterone and glucose in a free-living population of Australian freshwater crocodiles.

    PubMed

    Jessop, Tim S; Tucker, Anton D; Limpus, Colin J; Whittier, Joan M

    2003-06-01

    In this study we examined three aspects pertaining to adrenocortical responsiveness in free-ranging Australian freshwater crocodiles (Crocodylus johnstoni). First, we examined the ability of freshwater crocodiles to produce corticosterone in response to a typical capture-stress protocol. A second objective addressed the relationship between capture stress, plasma glucose and corticosterone. Next we examined if variation in basal and capture-stress-induced levels of plasma corticosterone was linked to ecological or demographic factors for individuals in this free-ranging population. Blood samples obtained on three field trips were taken from a cross-sectional sample of the population. Crocodiles were bled once during four time categories at 0, 0.5, 6, and 10h post-capture. Plasma corticosterone increased significantly with time post-capture. Plasma glucose also significantly increased with duration of capture-stress and exhibited a positive and significant relationship with plasma corticosterone. Significant variation in basal or stress induced levels of corticosterone in crocodiles was not associated with any ecological or demographic factors including sex, age class or the year of capture that the crocodiles were sampled from. However, three immature males had basal levels of plasma corticosterone greater than 2 standard deviations above the mean. While crocodiles exhibited a pronounced adrenocortical and hyperglycaemic response to capture stress, limited variation in adrenocortical responsiveness due to ecological and demographic factors was not evident. This feature could arise in part because this population was sampled during a period of environmental benigness.

  2. A giant crocodile in the Dubois Collection from the Pleistocene of Kali Gedeh (Java).

    PubMed

    Delfino, Massimo; De Vos, John

    2014-03-01

    The fauna of the Pleistocene Homo-bearing sites of Java has been well known for more than a century. A recent revision of the crocodylian remains confirmed both the validity of Gavialis bengawanicus and the synonymization of Crocodylus ossifragus with C. siamensis. Here we report on a still unpublished crocodylian specimen collected by Eugene Dubois in the latest Early Pleistocene of Kali Gedeh that can be tentatively referred to the genus Crocodylus. The size of the specimen, the approximately 1 m long lower jaw in particular, indicated that this crocodile attained a total length of approximately 6 or 7 m. Along with specimens from the Plio-Pleistocene of Africa, this material provides evidence for gigantism in Crocodylus. It is not clear whether or not the 'temperature-size rule' applies to fossil crocodylians, but due to the growing interest in predicting future temperature-related size changes of the extant organisms, it would be interesting to study in detail the past reaction to temperature changes of crocodylians and other terrestrial ectothermic animals.

  3. Saltwater icephobicity: Influence of surface chemistry on saltwater icing

    PubMed Central

    Carpenter, Katherine; Bahadur, Vaibhav

    2015-01-01

    Most studies on icephobicity focus on ice formation with pure water. This manuscript presents studies to understand the influence of surfaces on saltwater ice nucleation and propagation. Experiments are conducted to quantify the influence of surface chemistry on saltwater ice nucleation and to understand the utility of superhydrophobic surfaces for saltwater icephobicity. These experiments are conducted with pure water and two sodium chloride solutions, which represent the salinity of seawater and briny produced water. It is seen that the presence of salt slows down the ice front propagation velocity significantly. Saltwater droplet impact dynamics on superhydrophobic surfaces are also different from pure water. Saltwater droplets retract more and a greater fraction of impacting liquid is repelled from the superhydrophobic surface. It is seen that the greater bounciness of saltwater droplets is a result of slower ice nucleation propagation kinetics. These experiments indicate that superhydrophobic surfaces will have better resistance to impact icing with saltwater than pure water and can remain useful at temperatures as low as −40 °C. Overall, this work is a starting point for further studies on heterogeneous nucleation in saltwater and serves as a bridge between the widely studied freshwater icephobic surfaces and saltwater-related applications. PMID:26626958

  4. Metals and organochlorine pesticides in caudal scutes of crocodiles from Belize and Costa Rica.

    PubMed

    Rainwater, Thomas R; Wu, Ted H; Finger, Adam G; Cañas, Jaclyn E; Yu, Lu; Reynolds, Kevin D; Coimbatore, Gopal; Barr, Brady; Platt, Steven G; Cobb, George P; Anderson, Todd A; McMurry, Scott T

    2007-02-01

    Despite high animal diversity in the Neotropics and the largely unregulated use and disposal of pesticides and industrial chemicals in Central America, few data exist regarding accumulation of environmental contaminants in Central American wildlife. In this study we examined accumulation of metals and organochlorine (OC) pesticides in caudal scutes of crocodiles from Belize and Costa Rica. Scutes from Morelet's crocodiles (Crocodylus moreletii) from two sites in northern Belize were analyzed for metals, and scutes from American crocodiles (C. acutus) from one site in Costa Rica were analyzed for metals and OC pesticides. All scutes (n=25; one scute from each of 25 individuals) contained multiple contaminants. Mercury was the predominant metal detected, occurring in all scutes examined from both species. Other metals detected include cadmium, copper, lead, and zinc. American crocodile scutes from Costa Rica contained multiple OC pesticides, including endrin, methoxychlor, p,p'-DDE, and p,p'-DDT, all of which occurred in 100% of scutes analyzed (n=6). Mean metal and OC concentrations varied in relation to those previously reported in crocodilian scutes from other localities in North, Central, and South America. OC concentrations in American crocodile scutes were generally higher than those previously reported for other Costa Rican wildlife. Currently, caudal scutes may serve as general, non-lethal indicators of contaminant accumulation in crocodilians and their areas of occurrence. However, a better understanding of the relationships between pollutant concentrations in scutes, internal tissues, and environmental matrices at sample collection sites are needed to improve the utility of scutes in future ecotoxicological investigations.

  5. [On the identification of the species Griphobilharzia amoena Platt, Blair, Purdie et Melville, 1991, a parasite of crocodiles in Australia].

    PubMed

    Azimov, D A; Filimonova, L V; Shakabroev, É B; Akramova, F D

    2011-01-01

    The results of the study of typical specimens of the trematode G. amoena from blood vessels of the crocodile Crocodylus johnstoni in Australia are provided. The data obtained on the morphology of this parasite did not confirm the statement of Platt et al. (1991) that this species belongs to the family Schistosomatidae. Morphological data on G. amoena enable attributing it to the genus Vasotrema of the family Spirorchidae as a new species. In this connection, the monotypical genus Griphobilharzia (justified by Platt et al., 1991) becomes a synonym of the genus Vasotrema, while the subfamily Griphobilharziinae becomes a synonym of the subfamily Hapalotrematinae.

  6. Sexual size dimorphism and allometric growth of Morelet's crocodiles in captivity.

    PubMed

    Barrios-Quiroz, Gabriel; Casas-Andreu, Gustavo; Escobedo-Galván, Armando H

    2012-03-01

    Few studies have conducted morphological analyses of crocodilians, and little information exists on differences between size-classes and sexes in Neotropical crocodilians. In this study, we measured nine morphological traits in 121 captive Morelet's crocodiles Crocodylus moreletii (81 females and 40 males). Our results revealed that individuals < 2 m total length do not exhibit sexual dimorphism in morphometric characteristics. However, for crocodiles over 2 m in length, males were significantly larger than females in terms of dorsal-cranial length, cranial width, snout width and snout-ventral length. In general, morphological traits demonstrated a strongly significant relationship with total length at the smaller size class of 150-200 cm length. However, in the highest size class of 250-300 cm length (large adult males), morphological traits were no longer significantly related with total length. Male crocodiles demonstrated allometric growth of cranial morphology with significantly greater increase in cranial width, snout width, and mid-snout width relative to total length at higher size classes. Morphological dimorphism and allometric growth may be associated with adaptive strategies for reproductive success.

  7. Never smile at a crocodile: betting on electronic gaming machines is intensified by reptile-induced arousal.

    PubMed

    Rockloff, Matthew J; Greer, Nancy

    2010-12-01

    Tourists at the Koorana Saltwater Crocodile Farm in Coowonga, Queensland, Australia, including 62 males and 41 females, aged 18-66 (M = 34.2, SD = 13.3), were randomly assigned to play a laptop-simulated Electronic Gaming Machine (EGM) either: (1) prior to entry, or (2) after having held a 1-m saltwater-crocodile. Gambling behavior; including bet-size, speed of betting, final payouts and trials played on the EGM; was investigated with respect to participants' assigned arousal condition, problem-gambling status, and affective state. At-risk gamblers with few self-reported negative emotions placed higher average bets at the EGM after having held the crocodile when compared to the control. In contrast, at-risk gamblers with many self-reported negative emotions placed lower average bets at the EGM after having held the crocodile. The results suggest that high arousal can intensify gambling in at-risk players, but only if this feeling state is not perceived as a negative emotion.

  8. Reassessment of genome size in turtle and crocodile based on chromosome measurement by flow karyotyping: close similarity to chicken.

    PubMed

    Kasai, Fumio; O'Brien, Patricia C M; Ferguson-Smith, Malcolm A

    2012-08-23

    The genome size in turtles and crocodiles is thought to be much larger than the 1.2 Gb of the chicken (Gallus gallus domesticus, GGA), according to the animal genome size database. However, GGA macrochromosomes show extensive homology in the karyotypes of the red eared slider (Trachemys scripta elegans, TSC) and the Nile crocodile (Crocodylus niloticus, CNI), and bird and reptile genomes have been highly conserved during evolution. In this study, size and GC content of all chromosomes are measured from the flow karyotypes of GGA, TSC and CNI. Genome sizes estimated from the total chromosome size demonstrate that TSC and CNI are 1.21 Gb and 1.29 Gb, respectively. This refines previous overestimations and reveals similar genome sizes in chicken, turtle and crocodile. Analysis of chromosome GC content in each of these three species shows a higher GC content in smaller chromosomes than in larger chromosomes. This contrasts with mammals and squamates in which GC content does not correlate with chromosome size. These data suggest that a common ancestor of birds, turtles and crocodiles had a small genome size and a chromosomal size-dependent GC bias, distinct from the squamate lineage.

  9. Redescription and molecular characterisation of Dujardinascaris madagascariensis and a note on D. dujardini (Nematoda: Heterocheilidae), parasites of Crocodylus niloticus, with a key to Dujardinascaris spp. in crocodilians.

    PubMed

    Mašová, Šárka; Baruš, Vlastimil; Seifertová, Mária; Malala, John; Jirků, Miloslav

    2014-12-08

    An examination of one specimen of Nile crocodile, Crocodylus niloticus (Laurenti, 1768), from Lake Turkana (Kenya), revealed the presence of two ascaridoid nematodes belonging to the genus Dujardinascaris Baylis, 1947. Dujardinascaris madagascariensis Chabaud & Caballero, 1966 was studied by scanning electron microscopy, redescribed, and differentiated from D. dujardini (Travassos, 1920). Dujardinascaris madagascariencsis is the second of the genus to be sequenced. An internal fragment of the small ribosomal subunit and nuclear ribosomal DNA internal transcribed spacer 2 region were amplified--the slowly evolving 18S gene region was used for phylogenetic analysis. Molecular data confirmed affinity of D. madagascariensis to the family Heterocheilidae and revealed its closest relationship with D. waltoni. A key to the species of Dujardinascaris parasitizing crocodiles is provided.

  10. Reelin expression during embryonic brain development in Crocodylus niloticus.

    PubMed

    Tissir, F; Lambert De Rouvroit, C; Sire, J-Y; Meyer, G; Goffinet, A M

    2003-03-10

    The expression of reelin mRNA and protein was studied during embryonic brain development in the Nile crocodile Crocodylus niloticus, using in situ hybridization and immunohistochemistry. In the forebrain, reelin was highly expressed in the olfactory bulb, septal nuclei, and subpial neurons in the marginal zone of the cerebral cortex, dorsal ventricular ridge, and basal forebrain. At early stages, reelin mRNA was also detected in subventricular zones. In the diencephalon, the ventral lateral geniculate nuclei and reticular nuclei were strongly positive, with moderate expression in the habenula and focal expression in the hypothalamus. High expression levels were noted in the retina, the tectum, and the external granule cell layer of the cerebellum. In the brainstem, there was a high level of signal in cochleovestibular, sensory trigeminal, and some reticular nuclei. No expression was observed in the cortical plate or Purkinje cells. Comparison with reelin expression during brain development in mammals, birds, turtles, and lizards reveals evolutionarily conserved, homologous features that presumably define the expression profile in stem amniotes. The crocodilian cortex contains subpial reelin-positive cells that are also p73 positive, suggesting that they are homologous to mammalian Cajal-Retzius cells, although they express the reelin gene less intensely. Furthermore, the crocodilian cortex does not contain the subcortical reelin-positive cells that are typical of lizards but expresses reelin in subventricular zones at early stages. These observations confirm that reelin is prominently expressed in many structures of the embryonic brain in all amniotes and further emphasize the unique amplification of reelin expression in mammalian Cajal-Retzius cells and its putative role in the evolution of the cerebral cortex.

  11. Crocodile Technology. [CD-ROM].

    ERIC Educational Resources Information Center

    2000

    This high school physics computer software resource is a systems and control simulator that covers the topics of electricity, electronics, mechanics, and programming. Circuits can easily be simulated on the screen and electronic and mechanical components can be combined. In addition to those provided in Crocodile Technology, a student can create…

  12. Genetic evidence of hybridization between the critically endangered Cuban crocodile and the American crocodile: implications for population history and in situ/ex situ conservation.

    PubMed

    Milián-García, Y; Ramos-Targarona, R; Pérez-Fleitas, E; Sosa-Rodríguez, G; Guerra-Manchena, L; Alonso-Tabet, M; Espinosa-López, G; Russello, M A

    2015-03-01

    Inter-specific hybridization may be especially detrimental when one species is extremely rare and the other is abundant owing to the potential for genetic swamping. The Cuban crocodile (Crocodylus rhombifer) is a critically endangered island endemic largely restricted to Zapata Swamp, where it is sympatric with the widespread American crocodile (C. acutus). An on-island, C. rhombifer captive breeding program is underway with the goals of maintaining taxonomic integrity and providing a source of individuals for reintroduction, but its conservation value is limited by lack of genetic information. Here we collected mtDNA haplotypic and nuclear genotypic data from wild and captive C. rhombifer and C. acutus in Cuba to: (1) investigate the degree of inter-specific hybridization in natural (in situ) and captive (ex situ) populations; (2) quantify the extent, distribution and in situ representation of genetic variation ex situ; and (3) reconstruct founder relatedness to inform management. We found high levels of hybridization in the wild (49.1%) and captivity (16.1%), and additional evidence for a cryptic lineage of C. acutus in the Antilles. We detected marginally higher observed heterozygosity and allelic diversity ex situ relative to the wild population, with captive C. rhombifer exhibiting over twice the frequency of private alleles. Although mean relatedness was high in captivity, we identified 37 genetically important individuals that possessed individual mean kinship (MK) values lower than the population MK. Overall, these results will guide long-term conservation management of Cuban crocodiles for maintaining the genetic integrity and viability of this species of high global conservation value.

  13. Genetic evidence of hybridization between the critically endangered Cuban crocodile and the American crocodile: implications for population history and in situ/ex situ conservation

    PubMed Central

    Milián-García, Y; Ramos-Targarona, R; Pérez-Fleitas, E; Sosa-Rodríguez, G; Guerra-Manchena, L; Alonso-Tabet, M; Espinosa-López, G; Russello, M A

    2015-01-01

    Inter-specific hybridization may be especially detrimental when one species is extremely rare and the other is abundant owing to the potential for genetic swamping. The Cuban crocodile (Crocodylus rhombifer) is a critically endangered island endemic largely restricted to Zapata Swamp, where it is sympatric with the widespread American crocodile (C. acutus). An on-island, C. rhombifer captive breeding program is underway with the goals of maintaining taxonomic integrity and providing a source of individuals for reintroduction, but its conservation value is limited by lack of genetic information. Here we collected mtDNA haplotypic and nuclear genotypic data from wild and captive C. rhombifer and C. acutus in Cuba to: (1) investigate the degree of inter-specific hybridization in natural (in situ) and captive (ex situ) populations; (2) quantify the extent, distribution and in situ representation of genetic variation ex situ; and (3) reconstruct founder relatedness to inform management. We found high levels of hybridization in the wild (49.1%) and captivity (16.1%), and additional evidence for a cryptic lineage of C. acutus in the Antilles. We detected marginally higher observed heterozygosity and allelic diversity ex situ relative to the wild population, with captive C. rhombifer exhibiting over twice the frequency of private alleles. Although mean relatedness was high in captivity, we identified 37 genetically important individuals that possessed individual mean kinship (MK) values lower than the population MK. Overall, these results will guide long-term conservation management of Cuban crocodiles for maintaining the genetic integrity and viability of this species of high global conservation value. PMID:25335559

  14. First description of the male and redescription of the female of Paratrichosoma recurvum (Nematoda: Capillariidae), a skin-invading parasite of crocodiles in Mexico.

    PubMed

    Moravec, F; Vargas-Vázquez, J

    1998-06-01

    The first description of the male and a redescription of the female of the nematode Paratrichosoma recurvum (Solger, 1877), a parasite of the abdominal skin of crocodiles, are presented on the basis of specimens collected from Crocodilus moreletii Duméril et Bibron from the Lagoon of Celestún, Yucatan, Mexico. The morphology of P. recurvum proved to be very similar to that of the only other congeneric species, P. crocodylus Ashford et Muller, 1978, but the former differed from the latter in having distinctly protruding polar plugs on eggs, reduced mesenchymal cells at the esophagointestinal junction, and a smooth spicular surface as well as in geographic distribution. The finding of P. recurvum in C. moreletii represents a new host record. Paratrichosoma spp. appear to be widely distributed in tropical countries of different continents and may be of economic importance for crocodile farms.

  15. The American Crocodile in Biscayne Bay, Florida

    USGS Publications Warehouse

    Cherkiss, Michael S.; Romañach, Stephanie S.; Mazzotti, Frank J.

    2011-01-01

    Intensive crocodile monitoring programs conducted during the late 1970s and early 1980s in southern Florida resulted in an optimistic outlook for recovery of the protected species population. However, some areas with suitable crocodile habitat were not investigated, such as Biscayne Bay and the mainland shorelines of Barnes and Card Sounds. The objective of our study was to determine status and habitat use of crocodiles in the aforementioned areas. Spotlight and nesting surveys were conducted from September 1996 to December 2005. The results revealed annual increases in the number of crocodiles. Crocodiles preferred protected habitats such as canals and ponds. Fewer crocodiles were observed in higher salinity water. The distribution and abundance of crocodilians in estuaries is directly dependent on timing, amount, and location of freshwater delivery, providing an opportunity to integrate habitat enhancement with ongoing ecosystem restoration and management activities.

  16. Very high concentrations of DDE and toxaphene residues in crocodiles from the Ord River, Western Australia: an investigation into possible endocrine disruption.

    PubMed

    Yoshikane, Mitsuha; Kay, Winston R; Shibata, Yasuyuki; Inoue, Maki; Yanai, Tokuma; Kamata, Ryo; Edmonds, John S; Morita, Masatoshi

    2006-06-01

    Organochlorine pesticide concentrations, particularly those of the DDT family and of toxaphene, were measured by gas chromatography in samples of liver and body fat taken from Australian freshwater crocodiles Crocodylus johnstoni at three locations along the Ord River in Western Australia. The three sampling sites were the irrigation area, downstream of the irrigation area, and well upstream of the irrigation area; the last site serving as the control. DDT and toxaphene were applied in large and known quantities to cotton grown in the Ord Irrigation Area from 1964 to 1974. Thus the residues in the crocodile tissues are representative of the situation almost thirty years after the use of DDT and toxaphene ceased in the area. Very high concentrations of p,p'-DDE and toxaphene were found in the lipid-rich tissues that were examined. Livers and body fat from estuarine crocodiles Crocodylus porosus from the downstream site were also analysed. As p,p'-DDE and toxaphene are both known to be disruptive of endocrine systems, a range of blood parameters, including estradiol and testesterone concentrations, were also measured for all the animals studied. The ovaries and testes of the freshwater crocodiles were also examined histologically. There were no obvious effects on blood chemistry or gonad histology of the large burden of pesticides and their metabolites carried by exposed animals, although the limited number of samples and the variability of the breeding state of the animals examined may have masked possible effects. The isolation of the area, the accurately known applications of DDT and toxaphene, and the simplicity of the drainage system make the lower Ord River a unique natural laboratory for studying the long term breakdown and effects of pesticides applied in a tropical environment.

  17. A diagnosis of crocodile feeding traces on larger mammal bone, with fossil examples from the Plio-Pleistocene Olduvai Basin, Tanzania.

    PubMed

    Njau, Jackson K; Blumenschine, Robert J

    2006-02-01

    Neotaphonomic studies have determined the patterns of bone damage created by larger mammalian carnivores when consuming mammalian carcasses. Typically, mammalian carnivores gnaw and break bones to various degrees in order to access marrow, grease, and brain tissue. In contrast, crocodiles attempt to swallow whole parts of mammal carcasses, inflicting in the process tooth marks and other feeding traces on some of the bones they are unable to ingest. Although crocodiles are major predators of larger mammals along the margins of protected tropical rivers and lakes, their feeding traces on bone have received little systematic attention in neotaphonomic research. We present diagnostic characteristics of Crocodylus niloticus damage to uningested mammal bones resulting from a series of controlled observations of captive crocodile feeding. The resulting bone assemblages are composed of primarily complete elements from articulating units, some of which bear an extremely high density of shallow to deep, transversely to obliquely oriented tooth scores over often large areas of the bone, along with shallow to deep pits and punctures. Some of the tooth marks (bisected pits and punctures, hook scores) have a distinctive morphology we have not observed to be produced by mammalian carnivores. The assemblages are also characterized by the retention of both low- and high-density bone portions, an absence of gross gnawing, and minimal fragmentation. Together, the damage characteristics associated with feeding by crocodiles are highly distinctive from those produced by mammalian carnivores. Modern surface bone assemblages along the Grumeti River in Tanzania's Serengeti National Park contain a mixture of specimens bearing damage characteristic of crocodiles and mammalian carnivores. Comparison of Plio-Pleistocene fossil bones from Olduvai Gorge, Tanzania, to bones damaged by captive and free-ranging Nile crocodiles reveals direct evidence of fossil crocodilian feeding from larger

  18. Regional warming and the thermal regimes of American crocodile nests in the Tempisque Basin, Costa Rica.

    PubMed

    Murray, Christopher M; Easter, Michael; Padilla, Sergio; Marin, Mahmood Sasa; Guyer, Craig

    2016-08-01

    Spatial variation in global climate change makes population-specific responses to this enigmatic threat pertinent on a regional scale. Organisms with temperature-dependent sex determination (TSD) potentially possess a unique physiological susceptibility that threatens population viability if rapid environmental effects on sex ratios render populations non-viable. A heavily male-biased sex ratio for hatchling American crocodiles of the Tempisque Basin, Costa Rica requires assessment of how nest temperature affects sex determination at this site, how females might compensate for these effects when creating nests, and how current patterns of climate change might alter future sex ratios and survival in hatchling cohorts. We demonstrate high within-nest variation in temperature but predict a female bias at hatching based on nest temperatures quantified here. Further, our data suggest that egg size and metabolic heating associated with this factor outweighs microhabitat parameters and depth in influencing nest thermal regimes. Finally, we document regional warming in the Tempisque Basin over the last 15 years and project that further heating over the next 15 years will not yield hatchling sex ratios as male biased as those currently found at this site. Thus, we find no support for nest temperature or climate change as likely explanations for male-biased American crocodile (Crocodylus acutus) sex ratios in the Tempisque Basin.

  19. A third case of amelia in Morelet's crocodile from the Yucatan Peninsula.

    PubMed

    Charruau, Pierre; Niño-Torres, Carlos A

    2014-07-03

    Congenital defects in crocodilians have received little interest. In the context of global change and increasing threats to biodiversity, data on birth defects occurring in wildlife could be of importance for estimating the health of species populations and their ecosystems. Herein, we report the first case of amelia (i.e. absence of limbs) in Morelet's crocodiles Crocodylus moreletii from Mexico and the third on the southern Yucatan Peninsula. The crocodile in question was a juvenile (41 cm total length) captured in July 2012 in the Río Hondo, the river that forms the border between Mexico and Belize south of the state of Quintana Roo. The prevalence of this malformation in the C. moreletii population of Río Hondo (0.35%) is similar to that reported in 2 previous cases in Belize. Several causes of birth defects in crocodilians have previously been cited in the literature. Although we do not have relevant information to elucidate this case, we discuss some plausible explanations for this birth defect.

  20. The mitochondrial genomes of the iguana (Iguana iguana) and the caiman (Caiman crocodylus): implications for amniote phylogeny.

    PubMed

    Janke, A; Erpenbeck, D; Nilsson, M; Arnason, U

    2001-03-22

    The complete mitochondrial genomes of two reptiles, the common iguana (Iguana iguana) and the caiman (Caiman crocodylus), were sequenced in order to investigate phylogenetic questions of tetrapod evolution. The addition of the two species allows analysis of reptilian relationships using data sets other than those including only fast-evolving species. The crocodilian mitochondrial genomes seem to have evolved generally at a higher rate than those of other vertebrates. Phylogenetic analyses of 2889 amino-acid sites from 35 mitochondrial genomes supported the bird-crocodile relationship, lending no support to the Haematotherma hypothesis (with birds and mammals representing sister groups). The analyses corroborated the view that turtles are at the base of the bird-crocodile branch. This position of the turtles makes Diapsida paraphyletic. The origin of the squamates was estimated at 294 million years (Myr) ago and that of the turtles at 278 Myr ago. Phylogenetic analysis of mammalian relationships using the additional outgroups corroborated the Marsupionta hypothesis, which joins the monotremes and the marsupials to the exclusion of the eutherians.

  1. In Vitro and in Vivo Wound Healing Properties of Plasma and Serum from Crocodylus siamensis Blood.

    PubMed

    Jangpromma, Nisachon; Preecharram, Sutthidech; Srilert, Thanawan; Maijaroen, Surachai; Mahakunakorn, Pramote; Nualkaew, Natsajee; Daduang, Sakda; Klaynongsruang, Sompong

    2016-06-28

    The plasma and serum of Crocodylus siamensis have previously been reported to exhibit potent antimicrobial, antioxidant, and anti-inflammatory activities. During wound healing, these biological properties play a crucial role for supporting the formation of new tissue around the injured skin in the recovery process. Thus, this study aimed to evaluate the wound healing properties of C. siamensis plasma and serum. The collected data demonstrate that crocodile plasma and serum were able to activate in vitro proliferation and migration of HaCaT, a human keratinocyte cell line, which represents an essential phase in the wound healing process. With respect to investigating cell migration, a scratch wound experiment was performed which revealed the ability of plasma and serum to decrease the gap of wounds in a dose-dependent manner. Consistent with the in vitro results, remarkably enhanced wound repair was also observed in a mouse excisional skin wound model after treatment with plasma or serum. The effects of C. siamensis plasma and serum on wound healing were further elucidated by treating wound infections by Staphylococcus aureus ATCC 25923 on mice skin coupled with a histological method. The results indicate that crocodile plasma and serum promote the prevention of wound infection and boost the re-epithelialization necessary for the formation of new skin. Therefore, this work represents the first study to demonstrate the efficiency of C. siamensis plasma and serum with respect to their wound healing properties and strongly supports the utilization of C. siamensis plasma and serum as therapeutic products for injured skin treatment.

  2. [Genetic variability in captive populations of Crocodylus moreletii (Crocodylia: Crocodylidae) using microsatellites markers].

    PubMed

    Serna-Lagunes, Ricardo; González, Dolores; Díaz-Rivera, Pablo

    2012-03-01

    Crocodylus moreletii, an extinction threatened species, represents an emblem for tropical ecosystems in Mexico. Surprisingly, there is a lack of information about their genetic constitution, which should be evaluated for a proper management ex situ and for making decisions on the release of crocodiles into natural habitats. The aim of this study was to characterize and compare the genetic variability of four populations of C. moreletii (two wild versus two born ex situ). Through PCR were amplified seven microsatellite polymorphic loci, however a heterozygote deficit, diminished by the presence of null alleles, was found in the populations (average Ho=0.02). The AMOVA indicated that the highest proportion of genetic variability is within populations, and a limited genetic differentiation among populations (average F(ST)=0.03), probably due to high inbreeding index (average F(IS)=0.97). When comparing the genetic variability between and within other crocodilian species, we found that in C. moreletii is well below those reported. We concluded that the limited genetic variability in ex situ born populations is probably due to a founder effect derived from the social structure of their progenitors, and by the bottleneck effect, inferred by the limited effective population size, that historically characterizes their natural distribution in wild populations.

  3. Spatial Ecology of the American Crocodile in a Tropical Pacific Island in Central America

    PubMed Central

    Balaguera-Reina, Sergio A.; Venegas-Anaya, Miryam; Sánchez, Andrés; Arbelaez, Italo; Lessios, Harilaos A.; Densmore, Llewellyn D.

    2016-01-01

    Conservation of large predators has long been a challenge for biologists due to the limited information we have about their ecology, generally low numbers in the wild, large home ranges and the continuous expansion of human settlements. The American crocodile (Crocodylus acutus) is a typical apex predator, that has suffered from all of these characteristic problems, especially the latter one. Humans have had a major impact on the recovery of this species throughout its range, even though most of the countries it inhabits have banned hunting. The last decade has made it clear that in order to implement sound conservation and management programs, we must increase our understanding of crocodile spatial ecology. However, in only two countries where American crocodiles have telemetry studies even been published. Herein we have characterized the spatial ecology of C. acutus on Coiba Island, Panama, by radio-tracking (VHF transmitters) 24 individuals between 2010 and 2013, to determine movement patterns, home range, and habitat use. We have then compared our findings with those of previous studies to develop the most comprehensive assessment of American crocodile spatial ecology to date. Females showed a higher average movement distance (AMD) than males; similarly, adults showed a higher AMD than sub-adults and juveniles. However, males exhibited larger home ranges than females, and concomitantly sub-adults had larger home ranges than juveniles, hatchlings, and adults. There was an obvious relationship between seasonal precipitation and AMD, with increased AMD in the dry and “low-wet” seasons, and reduced AMD during the “true” wet season. We found disaggregate distributions according to age groups throughout the 9 habitat types in the study area; adults and hatchlings inhabited fewer habitat types than juveniles and sub-adults. These sex- and age-group discrepancies in movement and habitat choice are likely due to the influences of reproductive biology and Coiba

  4. Saltwater upconing zone of influence

    NASA Astrophysics Data System (ADS)

    Jakovovic, Danica; Werner, Adrian D.; de Louw, Perry G. B.; Post, Vincent E. A.; Morgan, Leanne K.

    2016-08-01

    In this study, we define and characterize the saltwater upconing zone of influence (SUZI). The SUZI is the region around a pumping well within which significant rise in the saltwater-freshwater interface occurs. While the zone of influence of a pumping well can be clearly defined in terms of hydraulics (e.g., drawdown), the SUZI has not been recognised and characterised, despite its importance for groundwater decision-making in coastal regions. We explore the SUZI under various conditions and compare common methods of investigation using both axisymmetric (1D and 2D vertical cross-section) and 3D simulations of saltwater upconing at the field scale, based on a combination of numerical and analytical approaches. The SUZI was found to be dependent on the relative magnitudes of pumping, regional flow, distance of the well from the coast, and position of the well above the interface, as expected. The three-dimensional coastal setting simulations revealed an asymmetric shape of the lateral extent of the SUZI, which is largest in the direction parallel to the coast. This occurs because the ocean and the inland extent of the seawater wedge limit the propagation of the SUZI perpendicular to the coast. Predictions of the SUZI using the Ghyben-Herzberg approximation, including cases where sloping interfaces occur (i.e., in contrast to the artificiality of horizontal interfaces used in axisymmetric approaches), provide reasonable first approximations of the SUZI. Numerical modelling of dispersive upconing in the 3D inclined interface case is influenced by practical limits to the model domain size and grid resolution. For example, the no-flow boundary condition at 1500 m from the pumping well elongates the SUZI in the direction parallel to the coast. This study extends previous concepts of well interference, which have previously been based on hydraulics only, by introducing the SUZI and characterising its extent, with consideration given to differences in commonly adopted

  5. Usefulness of oxidative stress biomarkers evaluated in the snout scraping, serum and Peripheral Blood Cells of Crocodylus moreletii from Southeast Campeche for assessment of the toxic impact of PAHs, metals and total phenols.

    PubMed

    Dzul-Caamal, Ricardo; Hernández-López, Abigail; Gonzalez-Jáuregui, Mauricio; Padilla, Sergio E; Girón-Pérez, Manuel Ivan; Vega-López, Armando

    2016-10-01

    In this study, we assessed the effects of inorganic and organic pollutants [As, Cu, Fe, Mn, Pb, Zn, PAHs (11 compounds) and total phenols] from a panel of biomarkers [O2, H2O2, thiobarbituric acid reactive substances (TBARS), carbonyl proteins (RCO), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and total cytochrome P450 activities] evaluated in the Snout Scraping (SS), Serum (S) and Peripheral Blood Cells (PBC) of the Morelet's crocodile (Crocodylus moreletii) inhabiting the reference locality (Lake Mocu) and polluted locality (Champoton River) using Principal Component Analysis (PCA). In male crocodiles from the reference site, only H2O2 in PBC was related to levels of fluoranthene on the Keel of Caudal Scales (KCS), but, in females, no association was detected. In contrast, a sex-linked response was detected in specimens from the polluted locality. Levels of benzo[a]pyrene, benzo[a]anthracene, chrysene, pyrene, phenanthrene, acenaphthene, Zn, Cu, and Pb in KCS of the female crocodil were related to the oxidative stress biomarkers on PBC, incluing the total CYP450 activity and levels of O2, H2O2 in serum. However, in male crocodiles, the oxidative stress in SS and in the serum (TBARS, RCO, CAT, GPx), and SOD in PBC was related to As, Pb, Cu, Fe, and benzo[a]pyrene water concentrations and to the burdens of As, Fe, Mn, indeno[1,2,3cd]pyrene in KCS. These results confirm the usefulness of minimal or non-invasive methods of evaluating the oxidative stress response for the environmental monitoring program on the wild Morelet's crocodile that is subject to special protection in Mexican guidelines.

  6. Thermal fluctuation within nests and predicted sex ratio of Morelet's Crocodile.

    PubMed

    Escobedo-Galván, Armando H; López-Luna, Marco A; Cupul-Magaña, Fabio G

    2016-05-01

    Understanding the interplay between thermal variations and sex ratio in reptiles with temperature-dependent sex determination is the first step for developing long-term conservation strategies. In case of crocodilians, the information is fragmentary and insufficient for establishing a general framework to consider how thermal fluctuation influence sex determination under natural conditions. The main goal of this study was to analyze thermal variation in nests of Crocodylus moreletii and to discuss the potential implications for predicting offspring sex ratio. The study was carried out at the Centro de Estudios Tecnológicos del Mar N° 2 and at the Sistemas Productivos Cocodrilo, Campeche, Mexico. Data was collected in the nesting season of Morelet's Crocodiles during three consecutive seasons (2007-2009). Thermal fluctuations for multiple areas of the nest chamber were registered by data loggers. We calculate the constant temperature equivalent based on thermal profiles among nests to assess whether there are differences between the nest temperature and its equivalent to constant temperature. We observed that mean nest temperature was only different among nests, while daily thermal fluctuations vary depending on the depth position within the nest chamber, years and nests. The constant temperature equivalent was different among and within nests, but not among survey years. We observed differences between constant temperature equivalent and mean nest temperature both at the top and in the middle of the nest cavities, but were not significantly different at the bottom of nest cavities. Our results enable examine and discuss the relevance of daily thermal fluctuations to predict sex ratio of the Morelet's Crocodile.

  7. Pulmonary anatomy in the Nile crocodile and the evolution of unidirectional airflow in Archosauria

    PubMed Central

    Hutchinson, John R.; Farmer, CG

    2013-01-01

    The lungs of birds have long been known to move air in only one direction during both inspiration and expiration through most of the tubular gas-exchanging bronchi (parabronchi). Recently a similar pattern of airflow has been observed in American alligators, a sister taxon to birds. The pattern of flow appears to be due to the arrangement of the primary and secondary bronchi, which, via their branching angles, generate inspiratory and expiratory aerodynamic valves. Both the anatomical similarity of the avian and alligator lung and the similarity in the patterns of airflow raise the possibility that these features are plesiomorphic for Archosauria and therefore did not evolve in response to selection for flapping flight or an endothermic metabolism, as has been generally assumed. To further test the hypothesis that unidirectional airflow is ancestral for Archosauria, we measured airflow in the lungs of the Nile crocodile (Crocodylus niloticus). As in birds and alligators, air flows cranially to caudally in the cervical ventral bronchus, and caudally to cranially in the dorsobronchi in the lungs of Nile crocodiles. We also visualized the gross anatomy of the primary, secondary and tertiary pulmonary bronchi of C. niloticus using computed tomography (CT) and microCT. The cervical ventral bronchus, cranial dorsobronchi and cranial medial bronchi display similar characteristics to their proposed homologues in the alligator, while there is considerable variation in the tertiary and caudal group bronchi. Our data indicate that the aspects of the crocodilian bronchial tree that maintain the aerodynamic valves and thus generate unidirectional airflow, are ancestral for Archosauria. PMID:23638399

  8. Membrane lipids and sodium pumps of cattle and crocodiles: an experimental test of the membrane pacemaker theory of metabolism.

    PubMed

    Wu, B J; Hulbert, A J; Storlien, L H; Else, P L

    2004-09-01

    The influence of membrane lipid composition on the molecular activity of a major membrane protein (the sodium pump) was examined as a test of the membrane pacemaker theory of metabolism. Microsomal membranes from the kidneys of cattle (Bos taurus) and crocodiles (Crocodylus porosus) were found to possess similar sodium pump concentrations, but cattle membranes showed a four- to fivefold higher enzyme (Na(+)-K(+)-ATPase) activity when measured at 37 degrees C. The molecular activity of the sodium pumps (ATP/min) from both species was fully recoverable when delipidated pumps were reconstituted with membrane from the original source (same species). The results of experiments involving species membrane crossovers showed cattle sodium pump molecular activity to progressively decrease from 3,245 to 1,953 (P < 0.005) to 1,031 (P < 0.003) ATP/min when subjected to two cycles of delipidation and reconstitution with crocodile membrane as a lipid source. In contrast, the molecular activity of crocodile sodium pumps progressively increased from 729 to 908 (P < 0.01) to 1,476 (P = 0.01) ATP/min when subjected to two cycles of delipidation and reconstitution with cattle membrane as a lipid source. The lipid composition of the two membrane preparations showed similar levels of saturated ( approximately 31-34%) and monounsaturated ( approximately 23-25%) fatty acids. Cattle membrane had fourfold more n-3 polyunsaturated fatty acids (11.2 vs. 2.9%) but had a reduced n-6 polyunsaturate content (29 vs. 43%). The results support the membrane pacemaker theory of metabolism and suggest membrane lipids and their polyunsaturates play a significant role in determining the molecular activity of the sodium pump.

  9. Redistribution of blood within the body is important for thermoregulation in an ectothermic vertebrate (Crocodylus porosus).

    PubMed

    Seebacher, Frank; Franklin, Craig E

    2007-11-01

    Changes in blood flow are a principal mechanism of thermoregulation in vertebrates. Changes in heart rate will alter blood flow, although multiple demands for limited cardiac output may compromise effective thermoregulation. We tested the hypothesis that regional differences in blood flow during heating and cooling can occur independently from changes in heart rate. We measured heart rate and blood pressure concurrently with blood flow in the crocodile, Crocodylus porosus. We measured changes in blood flow by laser Doppler flowmetry, and by injecting coloured microspheres. All measurements were made under different heat loads, with and without blocking cholinergic and beta-adrenergic receptors (autonomic blockade). Heart rates were significantly faster during heating than cooling in the control animals, but not when autonomic receptors were blocked. There were no significant differences in blood flow distribution between the control and autonomic blockade treatments. In both treatments, blood flow was directed to the dorsal skin and muscle and away from the tail and duodenum during heating. When the heat source was switched off, there was a redistribution of blood from the dorsal surface to the duodenum. Blood flow to the leg skin and muscle, and to the liver did not change significantly with thermal state. Blood pressure was significantly higher during the autonomic blockade than during the control. Thermal time constants of heating and cooling were unaffected by the blockade of autonomic receptors. We concluded that animals partially compensated for a lack of differential heart rates during heating and cooling by redistributing blood within the body, and by increasing blood pressure to increase flow. Hence, measures of heart rate alone are insufficient to assess physiological thermoregulation in reptiles.

  10. Saltwater and hard water bentonite mud

    SciTech Connect

    Pabley, A. S.

    1985-02-19

    A seawater/saltwater or hard water bentonite mud for use in drilling, and process for preparing same, comprising sequentially adding to seawater, to saltwater of a chloride concentration up to saturation, or hard water: a caustic agent; a filtration control agent; and bentonite. The resultant drilling mud meets API standards for viscosity and water loss, and is stable after aging and at tempertures in excess of 100/sup 0/ c. In another embodiment, the additives are premixed as dry ingredients and hydrated with seawater, saltwater or hard water. Unlike other bentonite drilling muds, the muds of this invention require no fresh water in their preparation, which makes them particularly useful at off-shore and remote on-shore drilling locations. The muds of this invention using bentonite further require less clay than known saltwater muds made with attapulgite, and provides superior filtration control, viscosity and stability.

  11. Environmental Impact Statement for Proposed Closure of Myrtle Beach Air Force Base, South Carolina

    DTIC Science & Technology

    1990-05-01

    saltwater interface, the water in the Intracoastal Waterway is usually soft, generally of good quality, and suitable for domestic and general industrial use...1 0 Coastal areas of Horry and Georgetown counties are classified "SA," i.e., total saltwaters suitable for propagation, survival, and harvesting of...American crocodile (Crocodylus acutus), inhabits freshwater rivers, lakes, swamps, and marshes, occasionally entering brackish or salt water. Their range

  12. Crocodiles and Alligators. Young Discovery Library Series.

    ERIC Educational Resources Information Center

    Farre, Marie

    This book is written for children ages 5 through 10. Part of a series designed to develop their curiosity, fascinate them and educate them, this volume describes the physical characteristics, behavior, and peculiar habits of crocodiles, including how to distinguish them from close relatives such as alligators, cayman, and gharials. (YP)

  13. Oklahoma's recent earthquakes and saltwater disposal.

    PubMed

    Walsh, F Rall; Zoback, Mark D

    2015-06-01

    Over the past 5 years, parts of Oklahoma have experienced marked increases in the number of small- to moderate-sized earthquakes. In three study areas that encompass the vast majority of the recent seismicity, we show that the increases in seismicity follow 5- to 10-fold increases in the rates of saltwater disposal. Adjacent areas where there has been relatively little saltwater disposal have had comparatively few recent earthquakes. In the areas of seismic activity, the saltwater disposal principally comes from "produced" water, saline pore water that is coproduced with oil and then injected into deeper sedimentary formations. These formations appear to be in hydraulic communication with potentially active faults in crystalline basement, where nearly all the earthquakes are occurring. Although most of the recent earthquakes have posed little danger to the public, the possibility of triggering damaging earthquakes on potentially active basement faults cannot be discounted.

  14. Conservation status and regional habitat priorities for the Orinoco crocodile: Past, present, and future

    PubMed Central

    Espinosa-Blanco, Ariel S.; Morales-Betancourt, Mónica A.; Seijas, Andrés E.; Lasso, Carlos A.; Antelo, Rafael; Densmore, Llewellyn D.

    2017-01-01

    Conservation of large predator species has historically been a challenge because they often overlap in resource utilization with humans; furthermore, there is a general lack of in-depth knowledge of their ecology and natural history. We assessed the conservation status of the Orinoco crocodile (Crocodylus intermedius), defining regional habitat priorities/crocodile conservation units (RHP/CCU) and regional research priorities (RRP) for this species. We also estimated a species distribution model (SDM) to define current suitable areas where the species might inhabit and/or that might be successfully colonized. The SDM area obtained with a suitable habitat probability ≥ 0.5 was 23,621 km2. Out of 2,562 km2 are included within protected areas in both Colombia (1,643 km2) and Venezuela (919 km2), which represents only 10.8% of C. intermedius’ potential range. Areas such as Laguna de Chigüichigüe (flood plain lagoon) exhibited an increase in population abundance. In contrast, localities such as the Cojedes and Manapire Rivers reported a significant reduction in relative abundance values. In Colombia, disparity in previous survey methods prevented accurate estimation of population trends. Only one study in this country described an increase over a 13 years span in the Ele, Lipa, and Cravo Norte River populations based on nest surveys. We defined 34 critical areas (16 in Colombia, 17 in Venezuela, and one covering both countries) where we need to preserve/research/monitor and/or generate management actions, 10 RHP/CCU (six from Venezuela and four from Colombia) and 24 RRP (11 from Venezuela, 12 from Colombia, and one in both countries). Caño Guaritico (Creek) and the Capanaparo River in Venezuela and the Ele, Lipa, Cravo Norte River System and the Guayabero River in Colombia were defined as areas with the most optimal conditions for long-term preservation and maintenance of C. intermedius populations. We conclude that the conservation status of this species is

  15. Conservation status and regional habitat priorities for the Orinoco crocodile: Past, present, and future.

    PubMed

    Balaguera-Reina, Sergio A; Espinosa-Blanco, Ariel S; Morales-Betancourt, Mónica A; Seijas, Andrés E; Lasso, Carlos A; Antelo, Rafael; Densmore, Llewellyn D

    2017-01-01

    Conservation of large predator species has historically been a challenge because they often overlap in resource utilization with humans; furthermore, there is a general lack of in-depth knowledge of their ecology and natural history. We assessed the conservation status of the Orinoco crocodile (Crocodylus intermedius), defining regional habitat priorities/crocodile conservation units (RHP/CCU) and regional research priorities (RRP) for this species. We also estimated a species distribution model (SDM) to define current suitable areas where the species might inhabit and/or that might be successfully colonized. The SDM area obtained with a suitable habitat probability ≥ 0.5 was 23,621 km2. Out of 2,562 km2 are included within protected areas in both Colombia (1,643 km2) and Venezuela (919 km2), which represents only 10.8% of C. intermedius' potential range. Areas such as Laguna de Chigüichigüe (flood plain lagoon) exhibited an increase in population abundance. In contrast, localities such as the Cojedes and Manapire Rivers reported a significant reduction in relative abundance values. In Colombia, disparity in previous survey methods prevented accurate estimation of population trends. Only one study in this country described an increase over a 13 years span in the Ele, Lipa, and Cravo Norte River populations based on nest surveys. We defined 34 critical areas (16 in Colombia, 17 in Venezuela, and one covering both countries) where we need to preserve/research/monitor and/or generate management actions, 10 RHP/CCU (six from Venezuela and four from Colombia) and 24 RRP (11 from Venezuela, 12 from Colombia, and one in both countries). Caño Guaritico (Creek) and the Capanaparo River in Venezuela and the Ele, Lipa, Cravo Norte River System and the Guayabero River in Colombia were defined as areas with the most optimal conditions for long-term preservation and maintenance of C. intermedius populations. We conclude that the conservation status of this species is still

  16. Transmission studies on Trichinella species isolated from Crocodylus niloticus and efficacy of fenbendazole and levamisole against muscle L1 stages in Balb C mice.

    PubMed

    Mukaratirwa, S; Magwedere, K; Matenga, E; Foggin, C M

    2001-03-01

    Forty-four Balb C mice, aged 18 weeks were infected with crocodile (Crocodylus niloticus)-derived Trichinella species. Of the infected mice, 32 were randomly divided into two groups each containing equal numbers of males and females; levamisole treated group and fenbendazole treated group. Each group was randomly subdivided into two subgroups as follows: levamisole group (subgroup 1: treated with levamisole on day 35 post infection, and subgroup 2: treated with levamisole on days 35 and 42 post infection) and fenbendazole group (subgroup 1: treated with fenbendazole on day 35 post infection and subgroup 2: treated with fenbendazole on days 35 and 42 post infection). The first subgroups treated on day 35 post infection were slaughtered on day 42 post infection and the second subgroups were treated on day 35 and day 42 post infection and slaughtered on day 49 post infection. Two female mice were infected a day after mating and were slaughtered together with the offspring on day 64 post-infection. Ten infected control mice were given 1 ml distilled water orally as placebo, and five of these were slaughtered on day 42 post infection. The results showed that the mean reproductive capacity index of this strain (RCI) in Balb C mice was 110. There was a significant reduction (P < 0.01) in larval counts in the single treatment groups (day 35) and in the double treatment groups (days 35 and 42) for both anthelmintics when compared the number of parasites in the control groups. After a single treatment, levamisole reduced the infection by 79.9% and fenbendazole by 76.7%. Following double treatments, levamisole reduced the infection by 95.5% and fenbendazole by 99.1%. There was evidence that the infected pregnant mice transmitted the parasite to their offspring. It is not certain whether the parasite was transmitted congenitally or transmammary Alternative ways of controlling the parasite in crocodile farms in Zimbabwe are discussed.

  17. Should I stay or should I go? Dispersal and population structure in small, isolated desert populations of West African crocodiles.

    PubMed

    Velo-Antón, Guillermo; Godinho, Raquel; Campos, João Carlos; Brito, José Carlos

    2014-01-01

    The maintenance of both spatial and genetic connectivity is paramount to the long-term persistence of small, isolated populations living in environments with extreme climates. We aim to identify the distribution of genetic diversity and assess population sub-structuring and dispersal across dwarfed desert populations of Crocodylus suchus, which occur in isolated groups, usually less than five individuals, along the mountains of Mauritania (West Africa). We used both invasive and non-invasive sampling methods and a combination of mitochondrial DNA (12 S and ND4) and microsatellite markers (32 loci and a subset of 12 loci). Our results showed high genetic differentiation and geographic structure in Mauritanian populations of C. suchus. We identified a metapopulation system acting within four river sub-basins (high gene flow and absence of genetic structure) and considerable genetic differentiation between sub-basins (FST range: 0.12-0.24) with rare dispersal events. Effective population sizes tend to be low within sub-basins while genetic diversity is maintained. Our study suggests that hydrographic networks (temporal connections along seasonal rivers during rainy periods) allow C. suchus to disperse and maintain metapopulation dynamics within sub-basins, which attenuate the loss of genetic diversity and the risk of extinction. We highlight the need of hydrographic conservation to protect vulnerable crocodiles isolated in small water bodies. We propose C. suchus as an umbrella species in Mauritania based on ecological affinities shared with other water-dependent species in desert environments.

  18. Should I Stay or Should I Go? Dispersal and Population Structure in Small, Isolated Desert Populations of West African Crocodiles

    PubMed Central

    Campos, João Carlos; Brito, José Carlos

    2014-01-01

    The maintenance of both spatial and genetic connectivity is paramount to the long-term persistence of small, isolated populations living in environments with extreme climates. We aim to identify the distribution of genetic diversity and assess population sub-structuring and dispersal across dwarfed desert populations of Crocodylus suchus, which occur in isolated groups, usually less than five individuals, along the mountains of Mauritania (West Africa). We used both invasive and non-invasive sampling methods and a combination of mitochondrial DNA (12 S and ND4) and microsatellite markers (32 loci and a subset of 12 loci). Our results showed high genetic differentiation and geographic structure in Mauritanian populations of C. suchus. We identified a metapopulation system acting within four river sub-basins (high gene flow and absence of genetic structure) and considerable genetic differentiation between sub-basins (FST range: 0.12–0.24) with rare dispersal events. Effective population sizes tend to be low within sub-basins while genetic diversity is maintained. Our study suggests that hydrographic networks (temporal connections along seasonal rivers during rainy periods) allow C. suchus to disperse and maintain metapopulation dynamics within sub-basins, which attenuate the loss of genetic diversity and the risk of extinction. We highlight the need of hydrographic conservation to protect vulnerable crocodiles isolated in small water bodies. We propose C. suchus as an umbrella species in Mauritania based on ecological affinities shared with other water-dependent species in desert environments. PMID:24740183

  19. Entrainment in coupled salt-water oscillators

    NASA Astrophysics Data System (ADS)

    Miyakawa, Kenji; Yamada, Kazuhiko

    1999-03-01

    The properties of coupling between two salt-water oscillators were studied. Two salt-water oscillators were coupled through the window of the partition wall. With an increase of the area of the window, the quasi-periodic mode, the in-phase mode, the bistable mode, and the out-of-phase mode appeared successively. A phase diagram of coupling was obtained in the plane of the area of the window and the diameter of the orifice of the cup. Furthermore, the effect of viscosity on coupling behaviors was investigated. In the boundary region between quasi-periodic coupling and in-phase coupling, the mode coupled with the phase difference of approximately π/4 was found. The experimental results were reproduced by the numerical simulation using coupled non-linear differential equations.

  20. Conservation and management of the American crocodile

    NASA Astrophysics Data System (ADS)

    Kushlan, James A.

    1988-11-01

    The American crocodile is a rare and endangered species, the range of which has contracted to disjunct locations such as Hispaniola, Jamaica, Cuba, Panama, and southern Florida. In an attempt to determine what factors might be limiting population growth, an extensive collaborative research program was conducted in 1978 82 in southern Florida. Limiting factors explicitly studied included climate, hurricanes, population dispersion, nesting habitat, fertility, predation, nest chamber environment, juvenile survivorship, artificial mortality, disturbance, and environmental contamination. No single natural factor limits the population, although in concert various factors result in low adult recruitment rates. Such natural limitations explain the natural rarity of this tropical species at the temperate limits of its range. Two artificial sources of mortality are death of adults on roads and the flooding of nests by high groundwater tables. These sources of mortality are potentially controllable by the appropriate management agencies. Active management, by such means as protection of individuals, habitat preservation and enhancement, nest site protection, and captive breeding, is also appropriate for assuring the survival of a rare species. The American crocodile has survived in southern Florida in face of extensive human occupancy of parts of its former nesting habitat, demonstrating the resilience of a threatened species. This case history illustrates the efficacy of conducting research aimed at testing specific management hypotheses, the importance of considering biographical constraints limiting population status in peripheral populations, the need for active management of rare species, and the role of multiple reserves in a conservation and management strategy.

  1. 76 FR 38619 - Proposed Information Collection; Comment Request; National Saltwater Angler Registry and State...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-01

    ... Saltwater Angler Registry and State Exemption Program AGENCY: National Oceanic and Atmospheric... currently approved collection. The National Saltwater Angler Registry Program (Registry Program) was... fisheries surveys, including establishing a national saltwater angler and for-hire vessel registry,...

  2. Surveys of tidal river systems in the northern territory of Australia and their crocodile populations

    SciTech Connect

    Vorlicek, G.C.; Messel, H.; Green, W.J.

    1986-01-01

    This book provides an update on the population dynamics of Crocodylus porous in the tidal waterways of Van Diemen Gulf and the Southern Gulf of Carpentaria, Australia, during 1984 and 1985. Contents: Prologue; Dedication; Introduction; Status of Crocodylus porous. July 1984, in the tidal waterways of the Alligator Region and in the Adelaide River System of Northern Australia: recovery underway; Resurvey of Crocodylus porous populations in the tidal waterways of the southern Gulf of Carpentaria, September - October 1985; Local knowledge - Northern Australia style.

  3. Monitoring Coastal Marshes for Persistent Saltwater Intrusion

    NASA Technical Reports Server (NTRS)

    Kalcic, Maria; Hall, Callie; Fletcher, Rose; Russell, Jeff

    2009-01-01

    Primary goal: Provide resource managers with remote sensing products that support ecosystem forecasting models requiring salinity and inundation data. Work supports the habitat-switching modules in the Coastal Louisiana Ecosystem Assessment and Restoration (CLEAR) model, which provides scientific evaluation for restoration management (Visser et al., 2008). Ongoing work to validate flooding with radar (NWRC/USGS) and enhance persistence estimates through "fusion" of MODIS and Landsat time series (ROSES A.28 Gulf of Mexico). Additional work will also investigate relationship between saltwater dielectric constant and radar returns (Radarsat) (ROSES A.28 Gulf of Mexico).

  4. 76 FR 4092 - National Saltwater Angler Registry Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-24

    ... National Oceanic and Atmospheric Administration RIN 0648-XA131 National Saltwater Angler Registry Program... INFORMATION: The final rule implementing the National Saltwater Angler Registry Program, 50 CFR part 600... registered under a qualifying State license and/or registry program, or to provide catch and effort data...

  5. 78 FR 49478 - National Saltwater Angler Registry Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-14

    ... National Oceanic and Atmospheric Administration RIN 0648-XC403 National Saltwater Angler Registry Program... Angler Registry Program. DATES: The registration fee will be required effective August 1, 2013. ADDRESSES... final rule implementing the National Saltwater Angler Registry Program, 50 CFR part 600, subpart P,...

  6. 76 FR 22082 - National Saltwater Angler Registry Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-20

    ... National Oceanic and Atmospheric Administration RIN 0648-XA368 National Saltwater Angler Registry Program... INFORMATION: The final rule implementing the National Saltwater Angler Registry Program, 50 CFR part 600... registered under a qualifying state license and/or registry program, or to provide catch and effort data...

  7. Crocodile tears and thread test of lacrimation.

    PubMed

    Yagi, N; Nakatani, H

    1986-01-01

    Patients with incomplete recovery from peripheral facial paralysis often complain of eye-watering while eating (crocodile tears or gustolacrimal reflex). In 55 patients (22 completely recovered from peripheral facial paralysis, 23 incompletely recovered, and ten with hemifacial spasm), lacrimation was monitored by the thread test (a modification of the Schirmer test) during taste stimulation. In the 22 patients with complete recovery, the results of the thread test did not differ before and after a sweet-sour candy was given (taste stimulation). All the patients with incomplete recovery showed either synkinesis or contracture. Lacrimation on the side of the lesion was high even before taste stimulation. After taste stimulation, a rapid and definite increase in lacrimation was observed. The results show that in patients with synkinesis and incomplete recovery after peripheral facial paralysis, the misdirected regeneration of the injured nerve fiber often occurs from the gustatory nerve to the lacrimal nerve, as well as between motor fibers.

  8. Crocodile attack in Australia: an analysis of its incidence and review of the pathology and management of crocodilian attacks in general.

    PubMed

    Caldicott, David G E; Croser, David; Manolis, Charlie; Webb, Grahame; Britton, Adam

    2005-01-01

    Crocodilians represent one of the oldest constant animal lineages on the planet, in no small part due to their formidable array of predatory adaptations. As both human and crocodilian populations expand, they increasingly encroach on each others' territories, bringing morbidity and mortality to both populations. In this article, the medical and herpetologic literature pertaining to injuries caused by crocodilians is reviewed, and the patterns of saltwater crocodile attacks in Australia from 1971 to 2004 are analyzed. In this review, we examine the features of crocodilians that contribute to explaining their evolutionary success, as well as the potential hazard they pose to humans. Only by understanding their capabilities is it possible to mitigate the potential threat to life and limb.

  9. 77 FR 51819 - Endangered Species; Receipt of Applications for Permit

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-27

    ... tortoise (Chelonoidis nigra) Radiated tortoise (Astrochelys radiata) Nile crocodile (Crocodiles niloticus... Sturnidae (does not include Aplonis pelzelni) Crocodylidae (does not include American crocodile) Applicant... period. Families: Felidae Lemuridae Species: Cuban crocodile (Crocodylus rhombifer)...

  10. Analysis of saltwater upconing beneath a pumping well

    USGS Publications Warehouse

    Reilly, T.E.; Goodman, A.S.

    1987-01-01

    Aquifer systems that contain freshwater and saltwater are usually stratified, with the more dense saltwater underlying the freshwater. A groundwater well discharging from the freshwater zone causes the saltwater to move upwards towards the well. This phenomenon is known as saltwater upconing. Two methods of analysis, the sharp-interface method and the fluid-density-dependent solute-transport method, are used to simulate saltwater upconing. Numerical experiments including comparisons of the two methods indicate: (1) for low to moderate pumpages the 50% isochlor and sharp interface correlate well; (2) the well can discharge significant concentrations of saltwater, even though a stable cone (according to the sharp-interface method) exists below the well screen; (3) an almost linear relationship exists between the well discharge rate and the concentration of the discharge at low pumping rates that maintain a stable cone; and (4) upconing is sensitive to transverse dispersivity, whereas it is insensitive to longitudinal dispersivity. A simulation of upconing at Test Site No. 4, Truro, Cape Cod, Massachusetts, indicates that the appropriate field value of transverse dispersivity is very small. This supports the validity of the sharp-interface assumption for analyzing the behavior of systems with thin saltwater-freshwater transition zones. ?? 1987.

  11. Saltwater intrusion in coastal regions of North America

    NASA Astrophysics Data System (ADS)

    Barlow, Paul M.; Reichard, Eric G.

    2010-02-01

    Saltwater has intruded into many of the coastal aquifers of the United States, Mexico, and Canada, but the extent of saltwater intrusion varies widely among localities and hydrogeologic settings. In many instances, the area contaminated by saltwater is limited to small parts of an aquifer and to specific wells and has had little or no effect on overall groundwater supplies; in other instances, saltwater contamination is of regional extent and has resulted in the closure of many groundwater supply wells. The variability of hydrogeologic settings, three-dimensional distribution of saline water, and history of groundwater withdrawals and freshwater drainage has resulted in a variety of modes of saltwater intrusion into coastal aquifers. These include lateral intrusion from the ocean; upward intrusion from deeper, more saline zones of a groundwater system; and downward intrusion from coastal waters. Saltwater contamination also has occurred along open boreholes and within abandoned, improperly constructed, or corroded wells that provide pathways for vertical migration across interconnected aquifers. Communities within the coastal regions of North America are taking actions to manage and prevent saltwater intrusion to ensure a sustainable source of groundwater for the future. These actions can be grouped broadly into scientific monitoring and assessment, engineering techniques, and regulatory approaches.

  12. Coastal Marsh Monitoring for Persistent Saltwater Intrusion

    NASA Technical Reports Server (NTRS)

    Hall, Callie M.

    2008-01-01

    This viewgraph presentation reviews NASA's work on the project that supports the Gulf of Mexico Alliance (GOMA) Governors Action Plan to monitor the coastal wetlands for saltwater intrusion. The action items that relate to the task are: (1) Obtain information on projected relative sea level rise, subsidence, and storm vulnerability to help prioritize conservation projects, including restoration, enhancement, and acquisition, and (2) Develop and apply ecosystem models to forecast the habitat structure and succession following hurricane disturbance and changes in ecological functions and services that impact vital socio-economic aspects of coastal systems. The objectives of the program are to provide resource managers with remote sensing products that support ecosystem forecasting models requiring salinity and inundation data. Specifically, the proposed work supports the habitat-switching modules in the Coastal Louisiana Ecosystem Assessment and Restoration (CLEAR) model, which provides scientific evaluation for restoration management.

  13. Cytogenetic characterization and fluorescence in situ hybridization of (GATA)10 repeats on established primary cell cultures from Indian water snake (Natrix piscator) and Indian mugger (Crocodylus palustris) embryos.

    PubMed

    Rao, L; Turlapati, R; Patel, M; Panda, B; Tosh, D; Mangalipalli, S; Tiwari, A; Orunganti, V P; Rose, D; Anand, A; Kulashekaran, M K; Priya, S R; Mishra, R K; Majumdar, K; Aggarwal, R K; Singh, L

    2009-01-01

    Sex determination among reptiles has continued to draw the attention of geneticists and the mechanisms involved have been extensively studied and documented in the past 3 decades. The setting up of primary cell lines of reptilian tissues is an important tool in the present study which is a unique aspect not applied in earlier studies. Establishing the cell lines from various species of reptiles would help in our understanding of the mechanisms of evolution and differentiation of sex chromosomes. Therefore, in the present study, we have established for the first time primary cell cultures from Indian water snake (Natrix piscator) and Indian mugger (Crocodylus palustris) embryos. In the preliminary growth stage, 2 types of cells, fibroblast- and epithelial-like, were found to be attached and proliferating in vitro. These fibroblast-like cell cultures were later overtaken by epithelial cells. The cell lines were grown in minimal essential medium supplemented with fetal bovine serum and subcultured for a period of 8-10 months. The morphology of cell types was kept under constant observation microscopically. Interestingly, at a subsequent passage of the cells sporadically scattered neuronal-like and beating cells were observed. The suitable temperature for growth of these cell cultures was 28-30 degrees C. Chromosome analysis was performed from the actively proliferating cells, which revealed 5 pairs of macrochromosomes and 15 pairs of microchromosomes in Natrix piscator, and 15 pairs of only macrochromosomes in Crocodylus palustris. (GATA)(n) repeats are well known to be associated with sex chromosomes. Fluorescence in situ hybridization performed with (GATA)(10) repeats delineated the W chromosome in the cells of Natrix piscator which has so far not been reported. This cell culture method has presently only been applied to water snakes and crocodile embryos in the current study, but it will be employed in other reptilian species and could go a long way to being a

  14. Mechanics of fragmentation of crocodile skin and other thin films.

    PubMed

    Qin, Zhao; Pugno, Nicola M; Buehler, Markus J

    2014-05-27

    Fragmentation of thin layers of materials is mediated by a network of cracks on its surface. It is commonly seen in dehydrated paintings or asphalt pavements and even in graphene or other two-dimensional materials, but is also observed in the characteristic polygonal pattern on a crocodile's head. Here, we build a simple mechanical model of a thin film and investigate the generation and development of fragmentation patterns as the material is exposed to various modes of deformation. We find that the characteristic size of fragmentation, defined by the mean diameter of polygons, is strictly governed by mechanical properties of the film material. Our result demonstrates that skin fragmentation on the head of crocodiles is dominated by that it features a small ratio between the fracture energy and Young's modulus, and the patterns agree well with experimental observations. Understanding this mechanics-driven process could be applied to improve the lifetime and reliability of thin film coatings by mimicking crocodile skin.

  15. Mechanics of fragmentation of crocodile skin and other thin films

    NASA Astrophysics Data System (ADS)

    Qin, Zhao; Pugno, Nicola M.; Buehler, Markus J.

    2014-05-01

    Fragmentation of thin layers of materials is mediated by a network of cracks on its surface. It is commonly seen in dehydrated paintings or asphalt pavements and even in graphene or other two-dimensional materials, but is also observed in the characteristic polygonal pattern on a crocodile's head. Here, we build a simple mechanical model of a thin film and investigate the generation and development of fragmentation patterns as the material is exposed to various modes of deformation. We find that the characteristic size of fragmentation, defined by the mean diameter of polygons, is strictly governed by mechanical properties of the film material. Our result demonstrates that skin fragmentation on the head of crocodiles is dominated by that it features a small ratio between the fracture energy and Young's modulus, and the patterns agree well with experimental observations. Understanding this mechanics-driven process could be applied to improve the lifetime and reliability of thin film coatings by mimicking crocodile skin.

  16. 76 FR 57757 - Endangered Species; Receipt of Applications for Permit

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-16

    ...-47878A The applicant requests a permit to import biological specimens of African dwarf crocodiles (Osteolaemus tetraspis tetraspis) and slender snouted crocodiles (Crocodylus cataphractus) collected from...

  17. Home range utilisation and long-range movement of estuarine crocodiles during the breeding and nesting season.

    PubMed

    Campbell, Hamish A; Dwyer, Ross G; Irwin, Terri R; Franklin, Craig E

    2013-01-01

    The estuarine crocodile (Crocodylus porosus) is the apex-predator in waterways and coastlines throughout south-east Asia and Australasia. C. porosus pose a potential risk to humans, and management strategies are implemented to control their movement and distribution. Here we used GPS-based telemetry to accurately record geographical location of adult C. porosus during the breeding and nesting season. The purpose of the study was to assess how C. porosus movement and distribution may be influenced by localised social conditions. During breeding, the females (2.92 ± 0.013 metres total length (TL), mean ± S.E., n = 4) occupied an area<1 km length of river, but to nest they travelled up to 54 km away from the breeding area. All tagged male C. porosus sustained high rates of movement (6.49 ± 0.9 km d(-1); n = 8) during the breeding and nesting period. The orientation of the daily movements differed between individuals revealing two discontinuous behavioural strategies. Five tagged male C. porosus (4.17 ± 0.14 m TL) exhibited a 'site-fidelic' strategy and moved within well-defined zones around the female home range areas. In contrast, three males (3.81 ± 0.08 m TL) exhibited 'nomadic' behaviour where they travelled continually throughout hundreds of kilometres of waterway. We argue that the 'site-fidelic' males patrolled territories around the female home ranges to maximise reproductive success, whilst the 'nomadic' males were subordinate animals that were forced to range over a far greater area in search of unguarded females. We conclude that C. porosus are highly mobile animals existing within a complex social system, and mate/con-specific interactions are likely to have a profound effect upon population density and distribution, and an individual's travel potential. We recommend that impacts on socio-spatial behaviour are considered prior to the implementation of management interventions.

  18. Species of Typhlophoros von Linstow, 1906 (Nematoda: Ascaridoidea) in Old World crocodilians.

    PubMed

    Sprent, J F

    1999-07-01

    A new species of the genus Typhlophoros von Linstow, 1906, T. spratti, is described from the freshwater crocodile Crocodylus johnstoni and the saltwater crocodile C. porosus in northern Australia. Specimens of the new species could not be compared with the type-species, T. lamellaris, as no preserved specimens of the latter species are known to exist. The new species differs from the descriptions of von Linstow (1906) and Maplestone (1930) in the number of interlabial ridges, the form of the ventriculus and absence of lateral alae. The taxonomic status and affinities of Typhlophoros are discussed.

  19. A saltwater flotation technique to identify unincubated eggs

    USGS Publications Warehouse

    Devney, C.A.; Kondrad, S.L.; Stebbins, K.R.; Brittingham, K.D.; Hoffman, D.J.; Heinz, G.H.

    2009-01-01

    Field studies on nesting birds sometimes involve questions related to nest initiation dates, length of the incubation period, or changes in parental incubation behavior during various stages of incubation. Some of this information can be best assessed when a nest is discovered before the eggs have undergone any incubation, and this has traditionally been assessed by floating eggs in freshwater. However, because the freshwater method is not particularly accurate in identifying unincubated eggs, we developed a more reliable saltwater flotation method. The saltwater method involves diluting a saturated saltwater solution with freshwater until a salt concentration is reached where unincubated eggs sink to the bottom and incubated eggs float to the surface. For Laughing Gulls (Leucophaeus atricilla), floating eggs in freshwater failed to identify 39.0% (N = 251) of eggs that were subsequently found by candling to have undergone incubation prior to collection. By contrast, in a separate collection of gull eggs, no eggs that passed the saltwater test (N = 225) were found by a later candling to have been incubated prior to collection. For Double-crested Cormorants (Phalacrocorax auritus), floating eggs in freshwater failed to identify 15.6% (N = 250) of eggs that had undergone incubation prior to collection, whereas in a separate collection, none of the eggs that passed the saltwater test (N = 85) were found by a later candling to have been incubated prior to collection. Immersion of eggs in saltwater did not affect embryo survival. Although use of the saltwater method is likely limited to colonial species and requires calibrating a saltwater solution, it is a faster and more accurate method of identifying unincubated eggs than the traditional method of floating eggs in freshwater.

  20. Reduction of saltwater intrusion by modifying hydraulic conductivity

    NASA Astrophysics Data System (ADS)

    Strack, O. D. L.; Stoeckl, L.; Damm, K.; Houben, G.; Ausk, B. K.; de Lange, W. J.

    2016-09-01

    We present an approach for reducing saltwater intrusion in coastal aquifers by artificially reducing the hydraulic conductivity in the upper part of selected areas by using a precipitate. We apply a previously presented analytical approach to develop formulas useful for the design of artificial barriers. Equations for the location of the tip of the saltwater wedge are presented and verified through a sand-tank experiment. The analysis is capable of computing discharges exactly, but requires the Dupuit-Forchheimer approximation to compute points of the interface between flowing fresh and stationary saltwater. We consider a vertical coastline and boundaries in the freshwater zone of either given discharge or given head. We demonstrate in the paper that reduction of the hydraulic conductivity in the upper part of a coastal aquifer will result in a decrease of saltwater intrusion, and present analytic expressions that can be used for design purposes. The previously presented analytical approach can be applied to design systems to reduce saltwater intrusion caused by pumping inland from the zone that contains saline groundwater.

  1. Oklahoma’s recent earthquakes and saltwater disposal

    PubMed Central

    Walsh, F. Rall; Zoback, Mark D.

    2015-01-01

    Over the past 5 years, parts of Oklahoma have experienced marked increases in the number of small- to moderate-sized earthquakes. In three study areas that encompass the vast majority of the recent seismicity, we show that the increases in seismicity follow 5- to 10-fold increases in the rates of saltwater disposal. Adjacent areas where there has been relatively little saltwater disposal have had comparatively few recent earthquakes. In the areas of seismic activity, the saltwater disposal principally comes from “produced” water, saline pore water that is coproduced with oil and then injected into deeper sedimentary formations. These formations appear to be in hydraulic communication with potentially active faults in crystalline basement, where nearly all the earthquakes are occurring. Although most of the recent earthquakes have posed little danger to the public, the possibility of triggering damaging earthquakes on potentially active basement faults cannot be discounted. PMID:26601200

  2. Effectiveness of saltwater baths in the treatment of epidermolysis bullosa.

    PubMed

    Petersen, Brian Woodford; Arbuckle, Harvey A; Berman, Stephen

    2015-01-01

    Current management of epidermolysis bullosa (EB) focuses on preventing secondary infections--a leading cause of mortality--by regularly cleaning and bandaging blisters and erosions and preventive bandaging of high-friction areas. Unfortunately the baths and showers used to remove bandages and clean the skin are often painful, causing lack of adherence and subsequent increases in infections, pain, and antimicrobial use. This study evaluates the hypothesis that bathing individuals with EB in saltwater is less painful than in normal bath water. The study also explores whether taking saltwater baths reduces infections as measured through skin pruritus, odor, discharge, and nonbathing pain. Participants recruited from the Children's Hospital Colorado Outpatient EB Clinic completed standardized questionnaires assessing the effects of the clinic's saltwater bathing recommendations; the data were analyzed using frequencies and Fisher tests. After starting saltwater baths, patients reported a significant reduction in pain (91%), pain medication use (66%), skin odor (31%), and skin discharge (44%). No significant differences were found with respect to the type of EB, age, length of time using baths, or amount of salt added. Saltwater baths are a noninvasive, low-cost, effective treatment that significantly reduces bathing pain, pain medication use, and some signs of skin infection. This treatment can be recommended to patients with all studied EB types without regard to age, the specific amount of salt used, bathing frequency, or pain level. Given the central role bathing and dressing changes play in the management of EB, the use of saltwater baths can lead to significant improvement in quality of life.

  3. Isolation and characterisation of crocodile and python ovotransferrins.

    PubMed

    Ciuraszkiewicz, Justyna; Olczak, Mariusz; Watorek, Wiesław

    2007-01-01

    Transferrins play a major role in iron homeostasis and metabolism. In vertebrates, these proteins are synthesised in the liver and dispersed within the organism by the bloodstream. In oviparous vertebrates additional expression is observed in the oviduct and the synthesised protein is deposited in egg white as ovotransferrin. Most research on ovotransferrin has been performed on the chicken protein. There is a limited amount of information on other bird transferrins, and until our previous paper on red-eared turtle protein there was no data on the isolation, sequencing and biochemical properties of reptilian ovotransferrins. Recently our laboratory deposited ten new sequences of reptilian transferrins in the EMBL database. A comparative analysis of these sequences indicates a possibility of different mechanisms of iron release among crocodile and snake transferrin. In the present paper we follow with the purification and analysis of the basic biochemical properties of two crocodile (Crocodilus niloticus, C. rhombifer) and one snake (Python molurus bivittatus) ovotransferrins. The proteins were purified by anion exchange and hydrophobic chromatography, and their N-terminal amino-acid sequences, molecular mass and isoelectric points were determined. All three proteins are glycosylated and their N-glycan chromatographic profiles show the largest contribution of neutral oligosaccharides in crocodile and disialylated glycans in python ovotransferrin. The absorption spectra of iron-saturated transferrins were analysed. Iron release from these proteins is pH-dependent, showing a biphasic character in crocodile ovotransferrins and a monophasic type in the python protein. The reason for the different types of iron release is discussed.

  4. Assessment of saltwater intrusion in southern coastal Broward County, Florida

    USGS Publications Warehouse

    Merritt, M.L.

    1996-01-01

    Of the counties in southeastern Florida, Broward County has experienced some of the most severe effects of saltwater intrusion into the surficial Biscayne aquifer because, before 1950, most public water-supply well fields in the county were constructed near the principal early population centers located less than 5 miles from the Atlantic Ocean. The construction of major regional drainage canals in the early 20th century caused a lowering of the water table and a gradual inland movement of the saltwater front toward the well fields. The U.S. Geological Survey began field investigations of saltwater intrusion in the Biscayne aquifer of southeastern Broward County in 1939. As part of the present study, the positions of the saltwater front in 1945, 1969, and 1993 were estimated using chloride concentrations of water samples collected between 1939 and 1994 from various monitoring and exploratory wells. The data indicate that, between 1945 and 1993, the saltwater front has moved as much as 0.5 mile inland in parts of the study area. The position and movement of the saltwater front were simulated numerically to help determine which of the various hydrologic factors and water-management features characterizing the coastal subsurface environment and its alteration by man are of significance in increasing or decreasing the degree of saltwater intrusion. Two representational methods were applied by the selection and use of appropriate model codes. The SHARP code simulates the position of the saltwater front as a sharp interface, which implies that no transition zone (a zone in which a gradational change between freshwater and saltwater occurs) separates freshwater and saltwater. The Subsurface Waste Injection Program (SWIP) code simulates a two-fluid, variable-density system using a convective-diffusion approach that includes a representation of the transition zone that occurs between the freshwater and saltwater bodies. The models were applied to: (1) approximately

  5. Mechanics of fragmentation of crocodile skin and other thin films

    PubMed Central

    Qin, Zhao; Pugno, Nicola M.; Buehler, Markus J.

    2014-01-01

    Fragmentation of thin layers of materials is mediated by a network of cracks on its surface. It is commonly seen in dehydrated paintings or asphalt pavements and even in graphene or other two-dimensional materials, but is also observed in the characteristic polygonal pattern on a crocodile's head. Here, we build a simple mechanical model of a thin film and investigate the generation and development of fragmentation patterns as the material is exposed to various modes of deformation. We find that the characteristic size of fragmentation, defined by the mean diameter of polygons, is strictly governed by mechanical properties of the film material. Our result demonstrates that skin fragmentation on the head of crocodiles is dominated by that it features a small ratio between the fracture energy and Young's modulus, and the patterns agree well with experimental observations. Understanding this mechanics-driven process could be applied to improve the lifetime and reliability of thin film coatings by mimicking crocodile skin. PMID:24862190

  6. Analysis of polarization decay of reinforced concrete in saltwater

    SciTech Connect

    Kumar, A.; Boy, J.H.

    1996-11-01

    Electrochemical impedance spectroscopy (EIS), polarization resistance, and polarization decay measurements techniques were used to analyze uncoated steel reinforcing rods encased in concrete and exposed to saltwater. A nested equivalent circuit containing a Warburg impedance was utilized to analyze the results. When rust is present on the steel, the Warburg impedance dominated the impedance response.

  7. Alligators and crocodiles as indicators for restoration of Everglades ecosystems

    USGS Publications Warehouse

    Mazzotti, Frank J.; Best, G. Ronnie; Brandt, Laura A.; Cherkiss, Michael S.; Jeffery, Brian M.; Rice, Kenneth G.

    2009-01-01

    Alligators and crocodiles integrate biological impacts of hydrological operations, affecting them at all life stages through three key aspects of Everglades ecology: (1) food webs, (2) diversity and productivity, and (3) freshwater flow. Responses of crocodilians are directly related to suitability of environmental conditions and hydrologic change. Correlations between biological responses and environmental conditions contribute to an understanding of species' status and trends over time. Positive or negative trends of crocodilian populations relative to hydrologic changes permit assessment of positive or negative trends in restoration. The crocodilian indicator uses monitoring parameters (performance measures) that have been shown to be both effective and efficient in tracking trends. The alligator component uses relative density (reported as an encounter rate), body condition, and occupancy rates of alligator holes; the crocodile component uses juvenile growth and hatchling survival. We hypothesize that these parameters are correlated with hydrologic conditions including depth, duration, timing, spatial extent and water quality. Salinity is a critical parameter in estuarine habitats. Assessments of parameters defined for crocodilian performance measures support these hypotheses. Alligators and crocodiles are the charismatic megafauna of the Everglades. They are both keystone and flagship species to which the public can relate. In addition, the parameters used to track trends are easy to understand. They provide answers to the following questions: How has the number of alligators or crocodiles changed? Are the animals fatter or thinner than they should be? Are the animals in the places (in terms of habitat and geography) where they should be? As surely as there is no other Everglades, no other single species defines the Everglades as does the American alligator. The Everglades is the only place in the world where both alligators and crocodiles exist. Crocodilians

  8. Home Range Utilisation and Long-Range Movement of Estuarine Crocodiles during the Breeding and Nesting Season

    PubMed Central

    Campbell, Hamish A.; Dwyer, Ross G.; Irwin, Terri R.; Franklin, Craig E.

    2013-01-01

    The estuarine crocodile (Crocodylus porosus) is the apex-predator in waterways and coastlines throughout south-east Asia and Australasia. C. porosus pose a potential risk to humans, and management strategies are implemented to control their movement and distribution. Here we used GPS-based telemetry to accurately record geographical location of adult C. porosus during the breeding and nesting season. The purpose of the study was to assess how C. porosus movement and distribution may be influenced by localised social conditions. During breeding, the females (2.92±0.013 metres total length (TL), mean ± S.E., n = 4) occupied an area<1 km length of river, but to nest they travelled up to 54 km away from the breeding area. All tagged male C. porosus sustained high rates of movement (6.49±0.9 km d−1; n = 8) during the breeding and nesting period. The orientation of the daily movements differed between individuals revealing two discontinuous behavioural strategies. Five tagged male C. porosus (4.17±0.14 m TL) exhibited a ‘site-fidelic’ strategy and moved within well-defined zones around the female home range areas. In contrast, three males (3.81±0.08 m TL) exhibited ‘nomadic’ behaviour where they travelled continually throughout hundreds of kilometres of waterway. We argue that the ‘site-fidelic’ males patrolled territories around the female home ranges to maximise reproductive success, whilst the ‘nomadic’ males were subordinate animals that were forced to range over a far greater area in search of unguarded females. We conclude that C. porosus are highly mobile animals existing within a complex social system, and mate/con-specific interactions are likely to have a profound effect upon population density and distribution, and an individual's travel potential. We recommend that impacts on socio-spatial behaviour are considered prior to the implementation of management interventions. PMID:23650510

  9. Saltwater-barrier line in Florida : concepts, considerations, and site examples

    USGS Publications Warehouse

    Hughes, Jerry L.

    1979-01-01

    Construction of canals and enlargement of streams in Florida has been mostly to alleviate impact of floods and to drain wetlands for development. Land drainage and heavy pumpage from coastal water-table aquifers has degraded potable ground and surface water with saltwater. Control of saltwater intrusion is possible through implementation of certain hydrologic principles. State of Florida statute 373.033 provides for a saltwater-barrier line in areas of saltwater intrusion along canals. A saltwater-barrier line is defined as the allowable landward limit that a canal shall be constructed or enlarged or a stream deepened or enlarged without a salinity-control structure seaward of the saltwater-barrier line. The salinity control structure controls saltwater intrusion along a surface-water channel and assists in controlling saltwater intrusion into shallow aquifers. This report briefly reviews the fundamentals of saltwater intrusion in surface-water channels and associated coastal aquifers, describes the effects of established saltwater-barrier lines in Florida, and gives a history of the use and benefits of salinity-control structures. (Woodard-USGS).

  10. Crocodile: An automated apparatus for organic crystal growth from solution

    NASA Astrophysics Data System (ADS)

    Gonzalez, F.; Cunisse, M.; Perigaud, A.

    CROCODILE ( CROissance de Cristaux Organiques par DIffusion Liquide dans l' Espace) is a space instrument dedicated to crystal growth from solution. The selected material N (4 nitrophenyl) (L) prolinol (NPP) is the result of studies on organic crystal in the frame of an extended program initiated by CNES for many years. The apparatus was flown aboard PHOTON, an automatic satellite, in April 1990, for a flight duration of more than 15 days. This paper describes the instrument design, with emphasis on specific and original technology well adapted to crystal growth from solution, and extendable to any space experiment on fluids. Preliminary details of the flight campaign will also be discussed.

  11. Supercritical Saltwater Spray for Marine Cloud Brightening (MCB)

    NASA Astrophysics Data System (ADS)

    Neukermans, A.; Cooper, G. F.; Foster, J.; Galbraith, L. K.; Johnston, D.; Ormond, B.; Wang, Q.

    2012-12-01

    Solar Radiation Management (SRM), including both stratospheric sulfur aerosol delivery and MCB, has emerged as the leading contender for geoengineering. Field research in MCB would require a technique capable of producing 1017 salt nuclei/sec from a single source on a seagoing vessel. Spraying supercritical saltwater has emerged as a viable technology, at least for research purposes. Under optimum conditions a single 50-μm nozzle produces 1014 suitable nuclei/sec. Power consumption is high (1-2 MW), but 95% of the required energy is in the form of heat that can probably be obtained from wasted ship-engine heat. While its implementation is conceptually simple, the corrosive nature of supercritical saltwater makes the material requirements very demanding. Progress on this work is detailed.

  12. Ward round--crocodile bites in Malawi: microbiology and surgical management.

    PubMed

    Wamisho, Biruk L; Bates, Jes; Tompkins, Marc; Islam, Raneem; Nyamulani, Noha; Ngulube, Chistopher; Mkandawire, Nyengo C

    2009-03-01

    We present a case series of 5 patients admitted over 5 months to Queen Elizabeth Central Hospital who had sustained injuries from a crocodile bite. Three patients required amputation of a limb. The severe soft tissue injury associated with a crocodile bite and the unusual normal oral flora of the crocodile create challenges in treatment. Progressive tissue destruction and haemolysis are complications of such infected wounds. An antibiotic regime is recommended that covers gram negative rods, anaerobes and may include doxycycline, as well as the need to have a low threshold for early amputation.

  13. Reclamation of saltwater-contaminated soil in Big Lake field

    SciTech Connect

    Weathers, M.L.; Moore, K.M.; Ford, D.L.; Curlee, C.K.

    1994-12-31

    Since the oil discovery at Santa Rita No. 1 in 1923, Big Lake in Reagan County, Texas, has produced 135 million bbl of oil and 1 billion bbl of saltwater. Until the early 1960`s, the accepted disposal method for saltwater was surface discharge to evaporation ponds north of the field. Approximately 200 million bbl of saltwater was discharged, resulting in 11 mi{sup 2} of barren landscape characterized by saline soils incapable of supporting vegetation. In 1989 an experimental project was initiated to reclaim 0.5 mi{sup 2} of affected area to rangeland productivity. An underground drainage system was installed to drain near-surface, salt-saturated perched water. Earthern terrances were constructed to reduce rainfall runoff and increase percolation to facilitate leaching of salts from the surface soil. Salt-saturated groundwater is drained by the system and pumped to injection wells for disposal. The excellent revegetation that has occurred over the test area after 2 years of operations is encouraging and has shown the need for enhancing the existing system with supplemental water from fresh-water wells, application of soil amending agents, and selective planting of salt-tolerant species.

  14. Persistent organic contaminants and steroid hormones levels in Morelet's crocodiles from the Southern Gulf of Mexico.

    PubMed

    Gonzalez-Jauregui, Mauricio; Valdespino, Carolina; Salame-Méndez, Arturo; Aguirre-León, Gustavo; Rendón-Vonosten, Jaime

    2012-04-01

    Effects of endocrine disruptors on reproductive variables of top predators, such as alligators and crocodiles, have long been cited. Due to their long life span, these predators provide us with historic contaminant annals. In this study we tried to test whether lifestyle (free-ranging vs. farm animals) and reproductive age of Morelet's crocodiles in Campeche, Mexico, affect the bioaccumulation of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). Subsequently, we tested to see whether their concentration was related to steroid hormones (testosterone and estradiol-17β) levels once normal cyclic hormone variation and reproductive age had been taken into account. From the group of contaminants considered (analyzed as families), only frequency of hexachlorocyclohexanes (∑HCH) and ∑PCB permitted analyses. Whereas there was a greater concentration of ∑HCH bioaccumulated by free-ranging crocodiles, ∑PCB was found in equal quantities in free-ranging and farm animals. No difference was observed in relation to reproductive age for any of the contaminants. However, ∑PCB concentrations were related to testosterone levels among female crocodiles. This androgenic effect of ∑PCB has not been reported previously. Because testosterone promotes aggressive behavior in vertebrates, excessive aggression during the estrous season, or when female crocodiles should be caring for their young, could result in reproductive failure in Morelet's crocodiles and potential long-term decline of the population.

  15. Changes in growth and osmoregulation during acclimation to saltwater in juvenile Amur sturgeon Acipenser schrenckii

    NASA Astrophysics Data System (ADS)

    Zhao, Feng; Zhuang, Ping; Zhang, Longzhen; Hou, Junli

    2010-05-01

    We evaluated the ability of juvenile Amur sturgeon ( Acipenser schrenckii) to osmoregulate and grow in saltwater. Hatchery-reared juveniles (mean weight 106.8 g, 5-month old) were transferred from freshwater to 10, 20, and 25 salinity saltwater over a period of 20 d. We measured the growth, serum osmolality, ion concentrations, and Na+/K+-ATPase activity. In addition, we prepared samples of gill tissue to quantify morphological changes in gill ultrastructure. Rearing in up to 25 saltwater for 30 d had no significant effect on growth. Similarly, serum osmolality and ion concentrations were similar to levels reported in other teleosts following acclimation to saltwater. Serum osmolality and Na+, Cl- concentrations increased significantly with the initial increase in salinity. Afterwards, levels tended to stabilize and then decrease. Serum K+ levels did not change during acclimation to saltwater. Gill Na+/K+-ATPase activity increased initially as salinity was increased. However, the activity later decreased and, finally stabilized at 3.7±0.1 μmol Pi/mg·prot·h in 25 saltwater (1.6 times higher than the level in those in freshwater). In fish that were held only in freshwater, the chloride cells were located in the interlamellar regions of the filament and at the base of the lamella. Following acclimation to 25 saltwater for 30 d, the number and size of chloride cells increased significantly. Our results suggest that juvenile Amur sturgeon is able to tolerate, and grow in, relatively high concentrations of saltwater.

  16. 75 FR 68604 - National Saltwater Angler Registry Program Designation of Exempted States

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-08

    ... National Oceanic and Atmospheric Administration RIN 0648-XZ91 National Saltwater Angler Registry Program... INFORMATION: The final rule implementing the National Saltwater Angler Registry Program, 50 CFR Subpart P, was... under a qualifying state license and/or registry program, or to provide catch and effort data from...

  17. Origins and delineation of saltwater intrusion in the Biscayne aquifer and changes in the distribution of saltwater in Miami-Dade County, Florida

    USGS Publications Warehouse

    Prinos, Scott T.; Wacker, Michael A.; Cunningham, Kevin J.; Fitterman, David V.

    2014-01-01

    Intrusion of saltwater into parts of the shallow karst Biscayne aquifer is a major concern for the 2.5 million residents of Miami-Dade County that rely on this aquifer as their primary drinking water supply. Saltwater intrusion of this aquifer began when the Everglades were drained to provide dry land for urban development and agriculture. The reduction in water levels caused by this drainage, combined with periodic droughts, allowed saltwater to flow inland along the base of the aquifer and to seep directly into the aquifer from the canals. The approximate inland extent of saltwater was last mapped in 1995. An examination of the inland extent of saltwater and the sources of saltwater in the aquifer was completed during 2008–2011 by using (1) all available salinity information, (2) time-series electromagnetic induction log datasets from 35 wells, (3) time-domain electromagnetic soundings collected at 79 locations, (4) a helicopter electromagnetic survey done during 2001 that was processed, calibrated, and published during the study, (5) cores and geophysical logs collected from 8 sites for stratigraphic analysis, (6) 8 new water-quality monitoring wells, and (7) analyses of 69 geochemical samples. The results of the study indicate that as of 2011 approximately 1,200 square kilometers (km2) of the mainland part of the Biscayne aquifer were intruded by saltwater. The saltwater front was mapped farther inland than it was in 1995 in eight areas totaling about 24.1 km2. In many of these areas, analyses indicated that saltwater had encroached along the base of the aquifer. The saltwater front was mapped closer to the coast than it was in 1995 in four areas totaling approximately 6.2 km2. The changes in the mapped extent of saltwater resulted from improved spatial information, actual movement of the saltwater front, or a combination of both. Salinity monitoring in some of the canals in Miami-Dade County between 1988 and 2010 indicated influxes of saltwater, with maximum

  18. Disposal of saltwater during well construction--Problems and solutions

    USGS Publications Warehouse

    Pitt, William A.; Meyer, Frederick W.; Hull, John E.

    1977-01-01

    The recent interest in the disposal of treated sewage effluent by deep-well injection into salt-water-filled aquifers has increased the need for proper disposal of salt water as more wells are drilled and tested each year.The effects on an unconfined aquifer of the improper disposal of salt water associated with the construction of three wells in southeastern Florida emphasize this need. In two of the wells provisions to prevent and detect salt-water contamination of the unconfined aquifer were practically nonexistent, and in one well extensive provisions were made. Of the three drilling sites the one with proper provision for detection presented no serious problem, as the ground water contaminated by the salt water was easily located and removed. The provisions consisted of drilling a brine-injection well to dispose of salt water discharged in drilling and testing operations, using a closed drilling circulation system to reduce spillage, installing shallow observation wells to map the extent and depth of any salt-water contamination of the shallow aquifer, and installing a dewatering system to remove contaminated ground water.

  19. Modeling Saltwater Intrusion in Highly Heterogeneous Coastal Aquifers

    NASA Astrophysics Data System (ADS)

    Safi, A.; El-Fadel, M.; Doummar, J.; Abou Najm, M.; Alameddine, I.

    2015-12-01

    In this study, a 3D variable-density flow and solute transport model SEAWAT was used to examine the impact of macroscopic variation in a soil matrix on widening or narrowing the thickness of the saltwater-freshwater mixing zone. Located along the Eastern Mediterranean (Beirut), the pilot aquifer consists of karstified limestone of Cretaceous age overlain by Upper Tertiary and Quaternary unconsolidated deposits. The model used the advanced pilot-points parameterization coupled with PEST to characterize spatial heterogenieity. Historically simulated water levels were relied upon to reduce potential numerical instabilities induced by insensitive parameters in transient calibration. The latter demonstrated a high degree of heterogeneity in the middle parts of the aquifer and along western coastlines with specification of a high hydraulic conductivity and low storativity in fault networks. The response of the aquifer to seasonal stresses such as climate cycles, pumping rates and recharge rates was manifested as high fluctuations in potentiometric surface due to potential fast flow pathways along faults. The final distribution of saltwater intrusion supports two mechanisms 1) lateral encroachment of recent seawater into the western zone of the aquifer which is of most concern due to high horizontal hydraulic conductivity in the wave direction and 2) upconing in the northwest and southwest of the aquifer due to large vertical hydraulic conductivities that tend to exacerbate the vertical movement of salinity.

  20. Comparative functional morphology of the masticatory apparatus in the long-snouted crocodiles.

    PubMed

    Endo, H; Aoki, R; Taru, H; Kimura, J; Sasaki, M; Yamamoto, M; Arishima, K; Hayashi, Y

    2002-08-01

    The masticatory muscles and their related structures of the skull were observed in the Indian gavial (Gavialis gangeticus), the false gavial (Tomistoma schlegelii), and the African slender-snouted crocodile (Mecistops cataphractus) to detail some morphological differences in comparison with the other crocodile species, and to compare and elucidate the functional strategy of themasticatory apparatus in these long-snouted species. The Musculus pterygoideus posterior was relatively smaller in the three species compared with many short-snouted crocodiles. It suggests that the masticatory power in fish-eating long-snouted species is not so high as in the short-snouted crocodiles, while the masticatory muscles were morphologically different among the three long-snouted species as follows. The M. pterygoideus posterior of the false gavial was extended in the lateral side of the lower jaw unlike the Indian gavial. The M. pseudotemporalis and the Fenestra supratemporalis were largely developed in the Indian gavial, however we suggest that the other two species possess the weak bundles in this muscle. The false gavial and the African slender-snouted crocodile have the pterygoid bone well-developed extending dorso-ventrally and it is suggested that the M. adductor mandibulae posterior attached to the pterygoid bone may be much larger than the Indian gavial. These data morphologically clarify the masticatory mechanism in the long-snouted crocodiles different from the short-snouted species, and demonstrate that the evolutional strategy to share the functional role in the masticatory muscles have been differently established between the Indian gavial and the other two species. We also obtained the morphological data in the fossil skull of the Machikane crocodile (Toyotamaphymeia machikanense) and concluded from the fossil characters that the considerable developments of the M.pterygoideus posterior and the M.pseudotemporalis in this species had not morphologically been

  1. Movement of Saltwater in the "2,000-Foot" Sand of the Baton Rouge Area, Louisiana

    NASA Astrophysics Data System (ADS)

    Tomaszewski, D. J.

    2005-05-01

    Ground-water withdrawals in southeastern Louisiana have caused saltwater to encroach into some freshwater aquifers. The most heavily pumped area, East Baton Rouge Parish, includes the city of Baton Rouge and surrounding areas. The Baton Rouge aquifer system includes 10 extensive aquifers that were pumped about 150 Mgal/d (million gallons per day) in 2003. Ground-water investigations in the 1960's delineated a freshwater-saltwater interface located at the Baton Rouge fault. Test drilling and water well data collected near the fault indicate that the fault is associated with major discontinuities in water levels and water quality. Generally, aquifers south of the fault contain saltwater and aquifers north of the fault contain freshwater with chloride concentrations less than 10 mg/L (milligrams per liter). Saltwater encroachment into freshwater areas north of the fault has been monitored and delineated with well networks in several aquifers. Saltwater was initially detected as early as the 1960's; by the 1990's saltwater had been detected in six of the aquifers north of the fault, including the "2,000-ft" sand. Northward encroachment of saltwater across the fault in the "2,000-ft" sand in East Baton Rouge Parish is in response to large water withdrawals from the aquifer totaling about 22.7 Mgal/d in the Parish in 2002. Encroachment of saltwater has been monitored by a system of wells. The approximate location of the freshwater-saltwater interface north of the fault was delineated for the years 1966, 1977, and 1992. At present, wells in the "2,000-ft" sand at two public-supply well fields located north of the fault are producing water with chloride concentrations approaching 200 mg/L. Wells at these fields may help protect the aquifer from northward advancement of saltwater by intercepting and discharging saltwater. In 2002, about 0.8 Mgal/d from the aquifer was withdrawn by the impacted wells. If withdrawals from the impacted wells were discontinued, saltwater could

  2. Thinking with Crocodiles: An Iconic Animal at the Intersection of Early-Modern Religion and Natural Philosophy.

    PubMed

    Weinreich, Spencer J

    2015-01-01

    This paper seeks to explore how culturally and religiously significant animals could shape discourses in which they were deployed, taking the crocodile as its case study. Beginning with the textual and visual traditions linking the crocodile with Africa and the Middle East, I read sixteenth- and seventeenth-century travel narratives categorizing American reptiles as "crocodiles" rather than "alligators," as attempts to mitigate the disruptive strangeness of the Americas. The second section draws on Ann Blair's study of "Mosaic Philosophy" to examine scholarly debates over the taxonomic identity of the biblical Leviathan. I argue that the language and analytical tools of natural philosophy progressively permeated religious discourse. Finally, a survey of more than 25 extant examples of the premodern practice of displaying crocodiles in churches, as well as other crocodilian elements in Christian iconography, provides an explanation for the ubiquity of crocodiles in Wunderkammern, as natural philosophy appropriated ecclesial visual vocabularies.

  3. [Population ecology of Crocodylus acutus (Reptilia: Crocodylidae) in Palmasola lagoon, Oaxaca, Mexico].

    PubMed

    García-Grajales, Jesús; Silva, Alejandra Buenrostro

    2014-03-01

    Population ecology of Crocodylus acutus (Reptilia: Crocodylidae) in Palmasola lagoon, Oaxaca, Mexico. Abundance and population structure are important parameters to evaluate and compare the conservation status of a population over time in a given area. This study describes the population abundance and structure of Crocodylus acutus in Palmasola lagoon, Oaxaca. The field works consisted of night surveys during the new moon phase, between the 21:00 and 24:00h. These were conducted during the dry and wet seasons and counted the number of individuals to obtain population estimates. Recorded encounter rates ranged from 32 to 109.3ind./ km in 40 journeys deployed with an average time of 18 minutes browsing. The estimated population size using the Messel's model ranged from 32.7 to 93 individuals. For both seasons, there was a marked dominance of subadults, followed by juveniles and to a lesser extent adult individuals, as well as undetermined individuals (i.e. unknown body/size/length), in both seasons. There was also a significant association with mangrove areas (26.1%) by juveniles; the subadults's individual use of superficial water (22.7%) and mangrove areas (15.7%); meanwhile the adults were observed on superficial water (9.7%). This information contributes to our understanding of the population ecology of C. acutus in the Palmasola lagoon where the estimated population size seems to show higher values when compared to other reports in the country.

  4. Conjunctive Management of Multi-Aquifer System for Saltwater Intrusion Mitigation

    NASA Astrophysics Data System (ADS)

    Tsai, F. T. C.; Pham, H. V.

    2015-12-01

    Due to excessive groundwater withdrawals, many water wells in Baton Rouge, Louisiana experience undesirable chloride concentration because of saltwater intrusion. The study goal is to develop a conjunctive management framework that takes advantage of the Baton Rouge multi-aquifer system to mitigate saltwater intrusion. The conjunctive management framework utilizes several hydraulic control techniques to mitigate saltwater encroachment. These hydraulic control approaches include pumping well relocation, freshwater injection, saltwater scavenging, and their combinations. Specific objectives of the study are: (1) constructing scientific geologic architectures of the "800-foot" sand, the "1,000-foot" sand, the "1,200-foot" sand, the "1,500-foot" sand, the "1,700-foot" sand, and the "2,000-foot" sand, (2) developing scientific saltwater intrusion models for these sands. (3) using connector wells to draw native groundwater from one sand and inject to another sand to create hydraulic barriers to halt saltwater intrusion, (4) using scavenger wells or well couples to impede saltwater intrusion progress and reduce chloride concentration in pumping wells, and (5) reducing cones of depression by relocating and dispersing pumping wells to different sands. The study utilizes optimization techniques and newest LSU high performance computing (HPC) facilities to derive solutions. The conjunctive management framework serves as a scientific tool to assist policy makers to solve the urgent saltwater encroachment issue in the Baton Rouge area. The research results will help water companies as well as industries in East Baton Rouge Parish and neighboring parishes by reducing their saltwater intrusion threats, which in turn would sustain Capital Area economic development.

  5. Potential for saltwater intrusion into the lower Tamiami aquifer near Bonita Springs, southwestern Florida

    USGS Publications Warehouse

    Shoemaker, W. Barclay; Edwards, K. Michelle

    2003-01-01

    A study was conducted to examine the potential for saltwater intrusion into the lower Tamiami aquifer beneath Bonita Springs in southwestern Florida. Field data were collected, and constant- and variable-density ground-water flow simulations were performed that: (1) spatially quantified modern and seasonal stresses, (2) identified potential mechanisms of saltwater intrusion, and (3) estimated the potential extent of saltwater intrusion for the area of concern. MODFLOW and the inverse modeling routine UCODE were used to spatially quantify modern and seasonal stresses by calibrating a constant-density ground-water flow model to field data collected in 1996. The model was calibrated by assuming hydraulic conductivity parameters were accurate and by estimating unmonitored ground-water pumpage and potential evapotranspiration with UCODE. Uncertainty in these estimated parameters was quantified with 95-percent confidence intervals. These confidence intervals indicate more uncertainty (or less reliability) in the estimates of unmonitored ground-water pumpage than estimates of pan-evaporation multipliers, because of the nature and distribution of observations used during calibration. Comparison of simulated water levels, streamflows, and net recharge with field data suggests the model is a good representation of field conditions. Potential mechanisms of saltwater intrusion into the lower Tamiami aquifer include: (1) lateral inland movement of the freshwater-saltwater interface from the southwestern coast of Florida; (2) upward leakage from deeper saline water-bearing zones through natural upwelling and upconing, both of which could occur as diffuse upward flow through semiconfining layers, conduit flow through karst features, or pipe flow through leaky artesian wells; (3) downward leakage of saltwater from surface-water channels; and (4) movement of unflushed pockets of relict seawater. Of the many potential mechanisms of saltwater intrusion, field data and variable

  6. Current and proposed regulations for salt-water disposal wells

    SciTech Connect

    Moody, T.

    1994-12-31

    In recent years, all aspects of hydrocarbon exploration and production (E&P) activities have drawn closer scrutiny in terms of existing and potential impairment of the environment. In addition to drilling, production, and transportation activities, the United States Environmental Protection Agency (USEPA) has focused on the nature of E&P wastes. Approximately 98% of the volume of wastes generated by E&P activities is salt water associated with the recovery of hydrocarbons. By far the majority of this waste is reinjected in Class II wells as a nonhazardous waste. Due to the tremendous volume of salt water disposed of in Class II injection wells, the USEPA continues to reevaluate the Federal salt-water injection well program, offering comments, revising its interpretation of existing regulations, and promulgating new regulations. The purpose of this paper is to provide a review of existing Federal Class II injection well regulations and to provide an overview of potential of newly promulgated regulations.

  7. Modeling saltwater intrusion in highly heterogeneous coastal aquifers

    NASA Astrophysics Data System (ADS)

    Safi, Amir; El-Fadel, Mutasem; Doummar, Joanna; Abou Najm, Majdi; Alameddine, Ibrahim

    2016-04-01

    In this study, a 3D variable-density flow and solute transport model SEAWAT was used to examine the impact of macroscopic variation in a soil matrix on widening or narrowing the thickness of the saltwater-freshwater mixing zone. Located along the Eastern Mediterranean (Beirut), the pilot aquifer consists of karstified limestone of Cretaceous age overlain by Upper Tertiary and Quaternary unconsolidated deposits. The model used the advanced pilot-points parameterization coupled with PEST to characterize spatial heterogeneity. Historically simulated water levels were relied upon to reduce potential numerical instabilities induced by insensitive parameters in transient calibration. The latter demonstrated a high degree of heterogeneity in the middle parts of the aquifer and along western coastlines with specification of a high hydraulic conductivity and low storativity in fault networks. The response of the aquifer to seasonal stresses such as climate cycles, pumping rates and recharge rates was manifested as high fluctuations in potentiometric surface due to potential fast flow pathways along faults. The final distribution of saltwater intrusion supports two mechanisms 1) lateral encroachment of recent seawater into the western zone of the aquifer which is of most concern due to high horizontal hydraulic conductivity in the wave direction and 2) upconing in the northwest and southwest of the aquifer due to large vertical hydraulic conductivities that tend to exacerbate the vertical movement of salinity. Acknowledgments This study is part of a program on climate change and seawater intrusion along the Eastern Mediterranean funded by the International Development Research Center (IDRC) of Canada at the American University of Beirut (AUB). Special thanks are extended to Dr. Charlotte Macalister at IDRC for her support and feedback in implementing this program.

  8. Crocodile head scales are not developmental units but emerge from physical cracking.

    PubMed

    Milinkovitch, Michel C; Manukyan, Liana; Debry, Adrien; Di-Poï, Nicolas; Martin, Samuel; Singh, Daljit; Lambert, Dominique; Zwicker, Matthias

    2013-01-04

    Various lineages of amniotes display keratinized skin appendages (feathers, hairs, and scales) that differentiate in the embryo from genetically controlled developmental units whose spatial organization is patterned by reaction-diffusion mechanisms (RDMs). We show that, contrary to skin appendages in other amniotes (as well as body scales in crocodiles), face and jaws scales of crocodiles are random polygonal domains of highly keratinized skin, rather than genetically controlled elements, and emerge from a physical self-organizing stochastic process distinct from RDMs: cracking of the developing skin in a stress field. We suggest that the rapid growth of the crocodile embryonic facial and jaw skeleton, combined with the development of a very keratinized skin, generates the mechanical stress that causes cracking.

  9. Maximal Aerobic and Anaerobic Power Generation in Large Crocodiles versus Mammals: Implications for Dinosaur Gigantothermy

    PubMed Central

    Seymour, Roger S.

    2013-01-01

    Inertial homeothermy, the maintenance of a relatively constant body temperature that occurs simply because of large size, is often applied to large dinosaurs. Moreover, biophysical modelling and actual measurements show that large crocodiles can behaviourally achieve body temperatures above 30°C. Therefore it is possible that some dinosaurs could achieve high and stable body temperatures without the high energy cost of typical endotherms. However it is not known whether an ectothermic dinosaur could produce the equivalent amount of muscular power as an endothermic one. To address this question, this study analyses maximal power output from measured aerobic and anaerobic metabolism in burst exercising estuarine crocodiles, Crocodylusporosus, weighing up to 200 kg. These results are compared with similar data from endothermic mammals. A 1 kg crocodile at 30°C produces about 16 watts from aerobic and anaerobic energy sources during the first 10% of exhaustive activity, which is 57% of that expected for a similarly sized mammal. A 200 kg crocodile produces about 400 watts, or only 14% of that for a mammal. Phosphocreatine is a minor energy source, used only in the first seconds of exercise and of similar concentrations in reptiles and mammals. Ectothermic crocodiles lack not only the absolute power for exercise, but also the endurance, that are evident in endothermic mammals. Despite the ability to achieve high and fairly constant body temperatures, therefore, large, ectothermic, crocodile-like dinosaurs would have been competitively inferior to endothermic, mammal-like dinosaurs with high aerobic power. Endothermy in dinosaurs is likely to explain their dominance over mammals in terrestrial ecosystems throughout the Mesozoic. PMID:23861968

  10. Maximal aerobic and anaerobic power generation in large crocodiles versus mammals: implications for dinosaur gigantothermy.

    PubMed

    Seymour, Roger S

    2013-01-01

    Inertial homeothermy, the maintenance of a relatively constant body temperature that occurs simply because of large size, is often applied to large dinosaurs. Moreover, biophysical modelling and actual measurements show that large crocodiles can behaviourally achieve body temperatures above 30°C. Therefore it is possible that some dinosaurs could achieve high and stable body temperatures without the high energy cost of typical endotherms. However it is not known whether an ectothermic dinosaur could produce the equivalent amount of muscular power as an endothermic one. To address this question, this study analyses maximal power output from measured aerobic and anaerobic metabolism in burst exercising estuarine crocodiles, Crocodylusporosus, weighing up to 200 kg. These results are compared with similar data from endothermic mammals. A 1 kg crocodile at 30°C produces about 16 watts from aerobic and anaerobic energy sources during the first 10% of exhaustive activity, which is 57% of that expected for a similarly sized mammal. A 200 kg crocodile produces about 400 watts, or only 14% of that for a mammal. Phosphocreatine is a minor energy source, used only in the first seconds of exercise and of similar concentrations in reptiles and mammals. Ectothermic crocodiles lack not only the absolute power for exercise, but also the endurance, that are evident in endothermic mammals. Despite the ability to achieve high and fairly constant body temperatures, therefore, large, ectothermic, crocodile-like dinosaurs would have been competitively inferior to endothermic, mammal-like dinosaurs with high aerobic power. Endothermy in dinosaurs is likely to explain their dominance over mammals in terrestrial ecosystems throughout the Mesozoic.

  11. The potential for saltwater intrusion in the Potomac aquifers of the York-James Peninsula, Virginia

    USGS Publications Warehouse

    Smith, Barry S.

    1999-01-01

    The most productive aquifers of the Virginia Coastal Plain are in the Potomac Formation. Water supplies in the Potomac aquifers are impaired, however, by saltwater in some areas. A two-dimensional, densitydependent, solute-transport model was used to investigate saltwater movement in the Potomac aquifers and the potential for saltwater intrusion or upward migration of saltwater. The model was designed to represent a simplified section of the Potomac aquifers and associated confining units near Lee Hall, Va. Solute-transport simulations show that the direction of ground-water flow and the hydrogeologic properties, particularly the permeability of aquifers and the distribution of confining sediments in the Potomac Formation, control the system hydrodynamics and saltwater movement in the Potomac aquifers. The simulations indicate lateral intrusion for the Lower Potomac aquifer near Lee Hall, Va. Velocity vectors of the simulations indicate that a hypothetical, but typical, production well in the Middle Potomac aquifer could induce upconing only within the immediate vicinity of the well. Migration of saltwater from the Middle and Lower Potomac aquifers east of the hypothetical well also was indicated by the simulations.

  12. Use of saltwater and freshwater habitats by wintering redheads in southern Texas

    USGS Publications Warehouse

    Woodin, Marc C.

    1994-01-01

    Behavioral data were gathered for redheads (Aythya americana Eyton) using saltwater and freshwater habitats in southern Texas, the northern portion of their major wintering range, in 1989–90. Saltwater and freshwater habitats were used for different purposes by wintering redheads. Approximately 41% of all redheads in saltwater habitats were feeding, while only 0.1% of redheads in freshwater habitats were feeding. Redheads in saltwater habitats drank infrequently (0.3%), but 7.5% of redheads in freshwater wetlands were drinking. Only 23 courting activities were observed, but all occurred in freshwater wetlands. This study showed that redheads depend on saltwater habitats for feeding, which confirmed similar results from recent studies of redheads in the central and southern portions of the Laguna Madre in southern Texas. This study also showed that redheads depend on freshwater wetlands as sources of drinking water. This concurred with data on redhead behavior in the central portion of the Laguna Madre in Texas, but not for redheads wintering in the southern part of the Laguna Madre. Both habitats, saltwater and freshwater, must be considered as integral components of the redhead winter range throughout southern Texas.

  13. Mitochondrial 16S ribosomal RNA gene for forensic identification of crocodile species.

    PubMed

    Naga Jogayya, K; Meganathan, P R; Dubey, Bhawna; Haque, I

    2013-05-01

    All crocodilians are under various threats due to over exploitation and these species have been listed in Appendix I or II of CITES. Lack of molecular techniques for the forensic identification of confiscated samples makes it difficult to enforce the law. Therefore, we herein present a molecular method developed on the basis on 16S rRNA gene of mitochondrial DNA for identification of crocodile species. We have developed a set of 16S rRNA primers for PCR based identification of crocodilian species. These novel primers amplify partial 16S rRNA sequences of six crocodile species which can be later combined to obtain a larger region (1290 bp) of 16S rRNA gene. This 16S rRNA gene could be used as an effective tool for forensic authentication of crocodiles. The described primers hold great promise in forensic identification of crocodile species, which can aid in the effective enforcement of law and conservation of these species.

  14. 75 FR 23279 - Receipt of Applications for Permit

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-03

    ... The applicant requests a permit to import a male American Crocodile (Crocodylus acutus) from Cherot-Rose American Crocodile Education Sanctuary, Toledo, Belize that was rescued from the wild for...

  15. The Henry semianalytical solution for saltwater intrusion with reduced dispersion

    NASA Astrophysics Data System (ADS)

    Zidane, Ali; Younes, Anis; Huggenberger, Peter; Zechner, Eric

    2012-06-01

    The Henry semianalytical solution for salt water intrusion is widely used for benchmarking density dependent flow codes. The method consists of replacing the stream function and the concentration by a double set of Fourier series. These series are truncated at a given order and the remaining coefficients are calculated by solving a highly nonlinear system of algebraic equations. The solution of this system is often subject to substantial numerical difficulties. Previous works succeeded to provide semianalytical solutions only for saltwater intrusion problems with unrealistic large amount of dispersion. In this work, different truncations for the Fourier series are tested and the Levenberg-Marquardt algorithm, which has a quadratic rate of convergence, is applied to calculate their coefficients. The obtained results provide semianalytical solutions for the Henry problem in the case of reduced dispersion coefficients and for two freshwater recharge values: the initial value suggested by Henry (1964) and the reduced one suggested by Simpson and Clement (2004). The developed semianalytical solutions are compared against numerical results obtained by using the method of lines and advanced spatial discretization schemes. The obtained semianalytical solutions improve considerably the worthiness of the Henry problem and therefore, they are more suitable for testing density dependent flow codes.

  16. Species-level diversification of African dwarf crocodiles (Genus Osteolaemus): a geographic and phylogenetic perspective.

    PubMed

    Eaton, Mitchell J; Martin, Andrew; Thorbjarnarson, John; Amato, George

    2009-03-01

    The taxonomy of the African dwarf crocodile (genus Osteolaemus) has been disputed since a novel morphotype was discovered in the early 20th Century. Because this poorly-known reptile is widely hunted throughout the forests of Central and West Africa, resolving the existence and extent of taxonomic units has important management and conservation implications. Lack of molecular data from individuals of known origin and historical disagreement on diagnostic morphological characters have hindered attempts to settle one of the most important taxonomic questions in the Crocodylia. In an effort to clarify the evolutionary relationships among dwarf crocodiles, we sequenced three mitochondrial and two nuclear genes using a large sample of dwarf crocodiles from known localities across major drainage basins of forested Africa. Concordant results from Bayesian, maximum likelihood, maximum parsimony and population aggregation analytical methods support a previously recognized division of the dwarf crocodile into a Congo Basin form (O. osborni) and a West African form (Osteolaemus tetraspis), but also reveal a third diagnosable lineage from West Africa warranting recognition as an separate taxonomic unit. Corrected genetic distances between geographic regions ranged from 0.2% to 0.6% in nuclear fragments and 10.0 to 16.2% in mitochondrial COI. Population aggregation, using fixed and alternate character (nucleotide) states to cluster or divide populations, recovered 232 such molecular characters in 4286 bp of sequence data and unambiguously aggregated populations into their respective geographic clade. Several previously recognized morphological differences coincide with our molecular analysis to distinguish Congo Basin crocodiles from the Ogooué Basin and West Africa. Discrete morphological characters have not yet been documented between the latter two regions, suggesting further work is needed or molecular data may be required to recognize taxonomic divisions in cases where

  17. Aquatic risk assessment of copper in freshwater and saltwater ecosystems of South Florida.

    PubMed

    Schuler, Lance J; Hoang, Tham C; Rand, Gary M

    2008-10-01

    A screening-level aquatic risk assessment was conducted for copper in south Florida's freshwater and saltwater environments. Risk was quantified by comparing the overlap between the probability distributions of copper exposure from surface water and sediment with the probability distributions of effects data obtained from laboratory studies. Copper concentrations in surface water and sediment in south Florida were summarized by county. For surface water, the highest concentrations of copper were found in Martin and St. Lucie counties for freshwater and saltwater, respectively. From the exposure probability distributions, the 90th centile values were estimated at 14.0 microg/L and 15.4 microg/L in freshwater and saltwater, respectively. Copper concentrations in sediment were evaluated from a probability distribution of predicted pore water concentrations. The 90th centile values of pore water concentrations from freshwater sediments ranged from 5.0 microg/L in Palm Beach County to 71.7 microg/L in Broward County. In saltwater sediments, the 90th centile values for pore water ranged from 26.1 microg/L in St. Lucie County to 27.3 microg/L in Miami-Dade County. Ecological effects data were obtained for acute and chronic copper effects in freshwater and saltwater. The 10th centile values for acute effects data were 21.2 microg/L and 9.8 microg/L for freshwater and saltwater species, respectively. For chronic effects, the 10th centile values were 3.8 microg/L and 3.9 microg/L for freshwater and saltwater species, respectively. The risk of acute copper exposure in surface water was generally low; however, the potential for ecological risk from chronic copper exposure was low to high in several counties including Lee, Martin, and St. Lucie counties. The risk of acute copper exposure in porewater from freshwater sediments also was low with the exception of St. Lucie and Broward counties. However, porewater from saltwater sediments posed a significant acute risk in Miami

  18. Saltwater in shallow aquifers in east-central and northeastern Louisiana and southeastern Arkansas

    USGS Publications Warehouse

    Huff, G.F.; Bonck, J.P.

    1993-01-01

    The chemistry of water from irrigation and monitor wells in east-central Louisiana indicates the presence of saltwater in the Mississippi River alluvial aquifer and the uppermost part of the Jasper aquifer system. The salinity of this groundwater makes it unsuitable for use in irrigation of salt-sensitive crops. The geochemistry of bromide (Br) and chloride (Cl) ions and strontium (Sr) isotopes indicated that this saltwater could have originated from the mixing of freshwater with briny water originating from the Carrizo-Wilcox aquifer at altitudes from 5,800 to 6,800 feet below sea level. However, in the absence of data on the concentrations of Br and Cl ions and the values of (87)Sr/(86)Sr in water from the Catahoula, Cockfield, and Sparta aquifers within the study area, no conclusive statement can be made on the origin of saltwater in the alluvial aquifer and the uppermost part of the Jasper aquifer system. Analyses of water from irrigation wells in northeastern Louisiana and southeastern Arkansas indicated the presence of saltwater in the Mississippi River alluvial aquifer. Saltwater probably moves from southern Chicot County, Arkansas, into northeastern Louisiana by flowing to the southwest along a fluvial channel eroded into the Cockfield Formation. Saltwater in the Mississippi River alluvial aquifer in northeastern Louisiana and southeastern Arkansas can be hazardous to salt-sensitive crops, such as rice, when used for irrigation. The geochemistry of Br and Cl ions indicated that saltwater in the Mississippi River alluvial aquifer of southern Chicot County in southeastern Arkansas has two geochemically distinct sources. One source, which has Br/Cl ratios less than that of modern seawater, could be derived from saltwater present in aquifers of Tertiary age; this saltwater could enter the alluvial aquifer by upward flow from below as part of the natural regional groundwater flow pattern. The other source, which has Br/Cl ratios greater than that of modern sea

  19. A sampling design and model for estimating abundance of Nile crocodiles while accounting for heterogeneity of detectability of multiple observers

    USGS Publications Warehouse

    Shirley, Matthew H.; Dorazio, Robert M.; Abassery, Ekramy; Elhady, Amr A.; Mekki, Mohammed S.; Asran, Hosni H.

    2012-01-01

    As part of the development of a management program for Nile crocodiles in Lake Nasser, Egypt, we used a dependent double-observer sampling protocol with multiple observers to compute estimates of population size. To analyze the data, we developed a hierarchical model that allowed us to assess variation in detection probabilities among observers and survey dates, as well as account for variation in crocodile abundance among sites and habitats. We conducted surveys from July 2008-June 2009 in 15 areas of Lake Nasser that were representative of 3 main habitat categories. During these surveys, we sampled 1,086 km of lake shore wherein we detected 386 crocodiles. Analysis of the data revealed significant variability in both inter- and intra-observer detection probabilities. Our raw encounter rate was 0.355 crocodiles/km. When we accounted for observer effects and habitat, we estimated a surface population abundance of 2,581 (2,239-2,987, 95% credible intervals) crocodiles in Lake Nasser. Our results underscore the importance of well-trained, experienced monitoring personnel in order to decrease heterogeneity in intra-observer detection probability and to better detect changes in the population based on survey indices. This study will assist the Egyptian government establish a monitoring program as an integral part of future crocodile harvest activities in Lake Nasser

  20. Saltwater intrusion as potential driver of phosphorus release from limestone bedrock in a coastal aquifer

    NASA Astrophysics Data System (ADS)

    Flower, Hilary; Rains, Mark; Lewis, David; Zhang, Jia-Zhong; Price, René

    2017-01-01

    An important but often overlooked consequence of saltwater intrusion is the potential increase of groundwater soluble reactive phosphorus concentrations. The phosphorus sorption dynamics of two limestone rocks of different composition were investigated by simulating seawater intrusion over a wide range of mixing ratios between freshwater and saltwater. Both rocks exhibited a logarithmic loss of sorption efficiency in mixtures containing more than approximately 3 mM Cl- concentration (100 mg Cl-/L; about <1% saltwater). We infer that aquifer solids immersed in freshwater would undergo phosphorus desorption in response to the introduction of this minor amount of seawater. This Cl- concentration is within the range designated as fresh water. Thus we conclude that increased soluble reactive phosphorus availability from saltwater-induced desorption may occur at the ion exchange front, which is actually landward of the saltwater intrusion front as it is commonly defined. Sorption efficiency in our experiments continued to decline as salinity increased, until Cl- concentration reached a second threshold of 50 or 200 mM (1700 or 7700 mg Cl-/L), depending on the rock composition, particularly iron content. Further increase in salinity would produce little increase in groundwater soluble reactive phosphorus concentration. Our results have implications for soluble reactive phosphorus availability in estuaries that receive mixing zone groundwater discharge.

  1. Experimental saltwater intrusion in coastal aquifers using automated image analysis: Applications to homogeneous aquifers

    NASA Astrophysics Data System (ADS)

    Robinson, G.; Ahmed, Ashraf A.; Hamill, G. A.

    2016-07-01

    This paper presents the applications of a novel methodology to quantify saltwater intrusion parameters in laboratory-scale experiments. The methodology uses an automated image analysis procedure, minimising manual inputs and the subsequent systematic errors that can be introduced. This allowed the quantification of the width of the mixing zone which is difficult to measure in experimental methods that are based on visual observations. Glass beads of different grain sizes were tested for both steady-state and transient conditions. The transient results showed good correlation between experimental and numerical intrusion rates. The experimental intrusion rates revealed that the saltwater wedge reached a steady state condition sooner while receding than advancing. The hydrodynamics of the experimental mixing zone exhibited similar traits; a greater increase in the width of the mixing zone was observed in the receding saltwater wedge, which indicates faster fluid velocities and higher dispersion. The angle of intrusion analysis revealed the formation of a volume of diluted saltwater at the toe position when the saltwater wedge is prompted to recede. In addition, results of different physical repeats of the experiment produced an average coefficient of variation less than 0.18 of the measured toe length and width of the mixing zone.

  2. Graphite Based Electrode for ECG Monitoring: Evaluation under Freshwater and Saltwater Conditions

    PubMed Central

    Thap, Tharoeun; Yoon, Kwon-Ha; Lee, Jinseok

    2016-01-01

    We proposed new electrodes that are applicable for electrocardiogram (ECG) monitoring under freshwater- and saltwater-immersion conditions. Our proposed electrodes are made of graphite pencil lead (GPL), a general-purpose writing pencil. We have fabricated two types of electrode: a pencil lead solid type (PLS) electrode and a pencil lead powder type (PLP) electrode. In order to assess the qualities of the PLS and PLP electrodes, we compared their performance with that of a commercial Ag/AgCl electrode, under a total of seven different conditions: dry, freshwater immersion with/without movement, post-freshwater wet condition, saltwater immersion with/without movement, and post-saltwater wet condition. In both dry and post-freshwater wet conditions, all ECG-recorded PQRST waves were clearly discernible, with all types of electrodes, Ag/AgCl, PLS, and PLP. On the other hand, under the freshwater- and saltwater-immersion conditions with/without movement, as well as post-saltwater wet conditions, we found that the proposed PLS and PLP electrodes provided better ECG waveform quality, with significant statistical differences compared with the quality provided by Ag/AgCl electrodes. PMID:27092502

  3. A well system to recover usable water from a freshwater-saltwater aquifer in Puerto Rico

    USGS Publications Warehouse

    Zack, Allen L.

    1988-01-01

    Aquifers in coastal areas of Puerto Rico commonly contain limited quantities of freshwater that occur as a thin layer at the surface of the water table. Many wells have been abandoned because well screens were inadvertently placed in saltwater parts of the aquifer. A scavenger/production well couple that can be installed in an abandoned well, screened in both freshwater and saltwater parts of the aquifer, provides an effective method for extracting freshwater from the well. Withdrawal of a sufficient quantity of water having low chloride concentrations, by use of a well couple, depends on the upward movement of saltwater within the aquifer when the well is pumped. Upward movement of saltwater depends on the relative concentrations of chloride in the borehole and on the distribution of horizontal and vertical hydraulic conductivity of the aquifer. For any well screened in an aquifer that contains both freshwater and saltwater, a family of curves can be constructed to represent all combinations of pumping rates and corresponding chloride loads when the scavenger well and the production well are being pumped simultaneously. The curves permit estimates of optimal withdrawals of freshwater based on the desired pumping rates and the levels of chloride concentration required for each well.

  4. Groundwater salinity in a floodplain forest impacted by saltwater intrusion.

    PubMed

    Kaplan, David A; Muñoz-Carpena, Rafael

    2014-11-15

    Coastal wetlands occupy a delicate position at the intersection of fresh and saline waters. Changing climate and watershed hydrology can lead to saltwater intrusion into historically freshwater systems, causing plant mortality and loss of freshwater habitat. Understanding the hydrological functioning of tidally influenced floodplain forests is essential for advancing ecosystem protection and restoration goals, however finding direct relationships between hydrological inputs and floodplain hydrology is complicated by interactions between surface water, groundwater, and atmospheric fluxes in variably saturated soils with heterogeneous vegetation and topography. Thus, an alternative method for identifying common trends and causal factors is required. Dynamic factor analysis (DFA), a time series dimension reduction technique, models temporal variation in observed data as linear combinations of common trends, which represent unexplained common variability, and explanatory variables. DFA was applied to model shallow groundwater salinity in the forested floodplain wetlands of the Loxahatchee River (Florida, USA), where altered watershed hydrology has led to changing hydroperiod and salinity regimes and undesired vegetative changes. Long-term, high-resolution groundwater salinity datasets revealed dynamics over seasonal and yearly time periods as well as over tidal cycles and storm events. DFA identified shared trends among salinity time series and a full dynamic factor model simulated observed series well (overall coefficient of efficiency, Ceff=0.85; 0.52≤Ceff≤0.99). A reduced multilinear model based solely on explanatory variables identified in the DFA had fair to good results (Ceff=0.58; 0.38≤Ceff≤0.75) and may be used to assess the effects of restoration and management scenarios on shallow groundwater salinity in the Loxahatchee River floodplain.

  5. Quantitative analysis of saltwater-freshwater relationships in groundwater systems-A historical perspective

    USGS Publications Warehouse

    Reilly, T.E.; Goodman, A.S.

    1985-01-01

    Although much progress has been made toward the mathematical description of saltwater-freshwater relationships in groundwater systems since the late 19th century, the advective and dispersive mechanisms involved are still incompletely understood. This article documents the major historical advances in this subject and summarizes the major direction of current studies. From the time of Badon Ghyben and Herzberg, it has been recognized that density is important in mathematically describing saltwater-freshwater systems. Other mechanisms, such as hydrodynamic dispersion, were identified later and are still not fully understood. Quantitative analysis of a saltwater-freshwater system attempts to mathematically describe the physical system and the important mechanisms using reasonable simplifications and assumptions. This paper, in developing the history of quantitative analysis discusses many of these simplifications and assumptions and their effect on describing and understanding the phenomenon. ?? 1985.

  6. Stochastic Optimization for an Analytical Model of Saltwater Intrusion in Coastal Aquifers

    PubMed Central

    Stratis, Paris N.; Karatzas, George P.; Papadopoulou, Elena P.; Zakynthinaki, Maria S.; Saridakis, Yiannis G.

    2016-01-01

    The present study implements a stochastic optimization technique to optimally manage freshwater pumping from coastal aquifers. Our simulations utilize the well-known sharp interface model for saltwater intrusion in coastal aquifers together with its known analytical solution. The objective is to maximize the total volume of freshwater pumped by the wells from the aquifer while, at the same time, protecting the aquifer from saltwater intrusion. In the direction of dealing with this problem in real time, the ALOPEX stochastic optimization method is used, to optimize the pumping rates of the wells, coupled with a penalty-based strategy that keeps the saltwater front at a safe distance from the wells. Several numerical optimization results, that simulate a known real aquifer case, are presented. The results explore the computational performance of the chosen stochastic optimization method as well as its abilities to manage freshwater pumping in real aquifer environments. PMID:27689362

  7. Determination of bioactivity of chemical fractions of liquid wastes using freshwater and saltwater algae and crustaceans

    SciTech Connect

    Walsh, G.E.; Garnas, R.L.

    1983-03-01

    Complex wastes from industrial and municipal outfalls were fractionated chemically and tested for toxicity with freshwater and saltwater algae and crustaceans. The organic fraction of each waste was subfractionated into acid-, base-, and neutral-extractable portions, and the inorganic fraction was subfractionated into its anion and cation components. All wastes affected growth of the algae Skeletonema costatum (saltwater) and Monoraphidium capricornutum (freshwater) or survival of Mysidopsis bahia (saltwater) and Daphnia magna (freshwater). Usually, bioactivity was limited to one or two subfractions. In some cases, algal growth was stimulated by a fraction or subfraction, whereas stimulation was not detected in whole waste. It is suggested that fractionation must be done in order to estimate the full potential impact of complex wastes on aquatic systems. The method can also be used to identify toxic factors before application of cost-effective control technology.

  8. Saltwater intrusion in the shallow aquifer in Martin and Palm Beach counties, Florida

    USGS Publications Warehouse

    Scott, W.B.; Land, L.F.; Rodis, H.G.

    1977-01-01

    Urban growth has been rapid in recent years in Palm Beach and Martin Counties, Fla. The withdrawal of large quantities of fresh ground water in the vicinity of the coast has reduced or locally reversed the natural seaward hydraulic gradient and, in places, allowed saltwater to advance landward in the aquifer, displacing freshwater. Maps show the position of the saltwater front in eight urban areas adjacent to the coast. The saltwater front, as shown on the profiles, is based on a chloride concentration of 250 mg/liter which is recommended as a limit for water that is considered potable. The chloride concentration of native freshwater almost always is less than 50 mg/liter in the coastal aquifer. (Woodard-USGS)

  9. Using state-of-the-art technology to evaluate saltwater intrusion in the Biscayne aquifer of Miami-Dade County, Florida

    USGS Publications Warehouse

    Prinos, Scott T.

    2014-01-01

    The fresh groundwater supplies of many communities have been adversely affected or limited by saltwater intrusion. An insufficient understanding of the origin of intruded saltwater may lead to inefficient or ineffective water-resource management. A 2008–2012 cooperative U.S. Geological Survey (USGS) and Miami-Dade County study of saltwater intrusion describes state-of-the art technology used to evaluate the origin and distribution of this saltwater.

  10. Saltwater intrusion into tidal freshwater marshes alters the biogeochemical processing of organic carbon

    NASA Astrophysics Data System (ADS)

    Neubauer, S. C.; Franklin, R. B.; Berrier, D. J.

    2013-12-01

    Environmental perturbations in wetlands affect the integrated plant-microbial-soil system, causing biogeochemical responses that can manifest at local to global scales. The objective of this study was to determine how saltwater intrusion affects carbon mineralization and greenhouse gas production in coastal wetlands. Working with tidal freshwater marsh soils that had experienced ~ 3.5 yr of in situ saltwater additions, we quantified changes in soil properties, measured extracellular enzyme activity associated with organic matter breakdown, and determined potential rates of anaerobic carbon dioxide (CO2) and methane (CH4) production. Soils from the field plots treated with brackish water had lower carbon content and higher C : N ratios than soils from freshwater plots, indicating that saltwater intrusion reduced carbon availability and increased organic matter recalcitrance. This was reflected in reduced activities of enzymes associated with the hydrolysis of cellulose and the oxidation of lignin, leading to reduced rates of soil CO2 and CH4 production. The effects of long-term saltwater additions contrasted with the effects of short-term exposure to brackish water during three-day laboratory incubations, which increased rates of CO2 production but lowered rates of CH4 production. Collectively, our data suggest that the long-term effect of saltwater intrusion on soil CO2 production is indirect, mediated through the effects of elevated salinity on the quantity and quality of autochthonous organic matter inputs to the soil. In contrast, salinity, organic matter content, and enzyme activities directly influence CH4 production. Our analyses demonstrate that saltwater intrusion into tidal freshwater marshes affects the entire process of carbon mineralization, from the availability of organic carbon through its terminal metabolism to CO2 and/or CH4, and illustrate that long-term shifts in biogeochemical functioning are not necessarily consistent with short

  11. Saltwater intrusion into tidal freshwater marshes alters the biogeochemical processing of organic carbon

    NASA Astrophysics Data System (ADS)

    Neubauer, S. C.; Franklin, R. B.; Berrier, D. J.

    2013-07-01

    Environmental perturbations in wetlands affect the integrated plant-microbial-soil system, causing biogeochemical responses that can manifest at local to global scales. The objective of this study was to determine how saltwater intrusion affects carbon mineralization and greenhouse gas production in coastal wetlands. Working with tidal freshwater marsh soils that had experienced roughly 3.5 yr of in situ saltwater additions, we quantified changes in soil properties, measured extracellular enzyme activity associated with organic matter breakdown, and determined potential rates of anaerobic carbon dioxide (CO2) and methane (CH4) production. Soils from the field plots treated with brackish water had lower carbon content and higher C : N ratios than soils from freshwater plots, indicating that saltwater intrusion reduced carbon availability and increased organic matter recalcitrance. This was reflected in reduced activities of enzymes associated with the hydrolysis of cellulose and the oxidation of lignin, leading to reduced rates of soil CO2 and CH4 production. The effects of long-term saltwater additions contrasted with the effects of short-term exposure to brackish water during three-day laboratory incubations, which increased rates of CO2 production but lowered rates of CH4 production. Collectively, our data suggest that the long-term effect of saltwater intrusion on soil CO2 production is indirect, mediated through the effects of elevated salinity on the quantity and quality of autochthonous organic matter inputs to the soil. In contrast, salinity, organic matter content, and enzyme activities directly influence CH4 production. Our analyses demonstrate that saltwater intrusion into tidal freshwater marshes affects the entire process of carbon mineralization, from the availability of organic carbon through its terminal metabolism to CO2 and/or CH4, and illustrate that long-term shifts in biogeochemical functioning are not necessarily consistent with short

  12. Drought-induced saltwater incursion leads to increased wetland nitrogen export.

    PubMed

    Ardón, Marcelo; Morse, Jennifer L; Colman, Benjamin P; Bernhardt, Emily S

    2013-10-01

    Coastal wetlands have the capacity to retain and denitrify large quantities of reactive nitrogen (N), making them important in attenuating increased anthropogenic N flux to coastal ecosystems. The ability of coastal wetlands to retain and transform N is being reduced by wetland losses resulting from land development. Nitrogen retention in coastal wetlands is further threatened by the increasing frequency and spatial extent of saltwater inundation in historically freshwater ecosystems, due to the combined effects of dredging, declining river discharge to coastal areas due to human water use, increased drought frequency, and accelerating sea-level rise. Because saltwater incursion may affect N cycling through multiple mechanisms, the impacts of salinization on coastal freshwater wetland N retention and transformation are not well understood. Here, we show that repeated annual saltwater incursion during late summer droughts in the coastal plain of North Carolina changed N export from organic to inorganic forms and led to a doubling of annual NH(4)(+) export from a 440 hectare former agricultural field undergoing wetland restoration. Soil solution NH(4)(+) concentrations in two mature wetlands also increased with salinization, but the magnitude of increase was smaller than that in the former agricultural field. Long-term saltwater exposure experiments with intact soil columns demonstrated that much of the increase in reactive N released could be explained by exchange of salt cations with sediment NH(4)(+). Using these findings together with the predicted flooding of 1661 km(2) of wetlands along the NC coast by 2100, we estimate that saltwater incursion into these coastal areas could release up to 18 077 Mg N, or approximately half the annual NH(4)(+) flux of the Mississippi River. Our results suggest that saltwater incursion into coastal freshwater wetlands globally could lead to increased N loading to sensitive coastal waters.

  13. Crack Initiation from Corrosion Pit in Three Aluminum Alloys Under Ambient and Saltwater Environments

    NASA Astrophysics Data System (ADS)

    Sabelkin, V.; Misak, H. E.; Perel, V. Y.; Mall, S.

    2016-04-01

    Corrosion-pit-to-crack transition behaviors of three aluminum alloys using two pit configurations were investigated under ambient and saltwater environments. Fatigue stress ranges for crack initiation from a through-pit were less than that from a corner-pit in both environments in all three materials, while stress intensity factor ranges showed the opposite trend. Further, stress ranges or stress intensity factor ranges for crack initiation were less in saltwater than that in ambient environment for both pit configurations. Fatigue damage mechanisms in a test environment were similar for both pit configurations in all three materials. An empirical relationship is proposed to estimate pit-to-crack transition fatigue cycles.

  14. Electrical Resistivity Imaging of Saltwater and Freshwater Along the Coast of Monterey Bay

    NASA Astrophysics Data System (ADS)

    Knight, R. J.; Pidlisecky, A.; Moran, T.; Goebel, M.

    2014-12-01

    A coastal region represents a dynamic interface where the processes of saltwater intrusion and freshwater flow create complex spatial and temporal changes in water chemistry. These changes in water chemistry affect both human use of coastal groundwater aquifers and the functioning of coastal ecosystems. Mapping out the subsurface distribution of saltwater and freshwater is a critical step in predicting, and managing, changes in water chemistry in coastal regions. Our research is focused on California's Monterey Bay region where agriculturally-intensive land meets the sensitive marine environment of the Monterey Bay National Marine Sanctuary. Along the coast of Monterey Bay extensive groundwater extraction (groundwater provides more than 80% of the area's water supply) has led to saltwater intrusion into aquifers at various locations. To date, the mapping of saltwater intrusion has relied on measurements of changing water chemistry in monitoring wells. But it is challenging with wells to capture the spatially complex hydrostratigraphy resulting from changing depositional environments and numerous faulting events. We suggest that geophysical methods be used to map and monitor the distribution of saltwater and freshwater by acquiring non-invasive, high-resolution continuous images of the subsurface. In a pilot study conducted over the past four years, we used electrical resistivity imaging to successfully identify regions of saltwater and freshwater 150 m below sea level along a 7 km stretch of the southern Monterey Bay coast. We employed large-offset electrical resistance tomography using a 96-electrode system with an overall array length of 860 m. The results showed excellent agreement with measurements in nearby monitoring wells. The large-scale image provided by the geophysical measurements revealed the hydrostratigraphic controls on the spatial distribution of the saltwater/freshwater interface. In October 2014 we will expand this study, using large

  15. The first case of intersexuality in an African dwarf crocodile (Osteolaemus tetraspis).

    PubMed

    Langer, Sandra; Ternes, Kerstin; Widmer, Dimitri; Mutschmann, Frank

    2014-01-01

    To the authors knowledge this is the first case of intersexuality in an African dwarf crocodile (Osteolaemus tetraspis). An adult African dwarf crocodile with a male-typical phenotype lived at Zoo Duisburg in Germany for 10 years. It died in October 2012 despite intensive treatment as a result of terminal septicemia. After a detailed pathological examination the gonads were histologically confirmed as ovotestes. Half of the 22 extant species of crocodilians have been examined for occurrence of temperature dependent sex determination (TSD). In TSD reptiles, masculinizing temperatures yield 100% or a majority of males, whereas feminizing temperatures yield 100% or a majority of females. In the transition range of temperature (TRT), a mix of males, females and sometimes intersexes are obtained. However, the molecular mechanisms behind TSD and an explanation for the occurrence of intersexuality remain elusive.

  16. Re-evaluating the effect of harvesting regimes on Nile crocodiles using an integral projection model.

    PubMed

    Wallace, Kevin; Leslie, Alison; Coulson, Tim

    2013-01-01

    Crocodile populations are size-structured, and for populations that are subject to harvesting, removal is typically size selective. For this reason, size-structured matrix models are typically used to analyse the dynamics of crocodile populations. The boundaries between the size classes used to classify individuals in these models are typically chosen arbitrarily. This is problematic because results can depend upon the number and width of size classes. The recent development of continuous character population models termed integral projection models (IPM) has removed the need to arbitrarily classify individuals. These models are yet to be applied to harvested animal populations. Using information obtained from the literature, we develop an IPM for crocodiles. We use perturbation analyses to investigate how altering size-specific demographic rates influences the population growth rate and the strength of selection on snout to vent length. We find that perturbations can lead to complex responses. Sensitivity analysis to population growth and fertility selection reveals that the smallest animals and the sizes of early breeding individuals and their eggs may have more influence on these population biology parameters than previously thought. Although our model is relatively simple, our results show that IPM can be used to gain theoretical insight into the possible consequences of altering size-specific demographic rates on the population and evolutionary ecology of harvested populations.

  17. 76 FR 32142 - Proposed Information Collection; Comment Request; Alaska Saltwater Sportfishing Economic Survey

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-03

    ... Saltwater Sportfishing Economic Survey AGENCY: National Oceanic and Atmospheric Administration (NOAA... economic analyses of marine sport fishing in Alaska. This survey is necessary to understand the factors that affect the economic value of marine recreational fishing trips and improve estimates of...

  18. Responses of hybrid striped bass to waterborne and dietary copper in freshwater and saltwater

    USGS Publications Warehouse

    Bielmyer, G.K.; Gatlin, D.; Isely, J.J.; Tomasso, J.; Klaine, S.J.

    2005-01-01

    Mechanisms of copper toxicity and consequences of exposure vary due to uptake route and ionoregulatory status. The goal of this research was to develop a model fish system to assess the influence of different Cu exposure routes (waterborne or dietary) on bioavailability, uptake, and effects in hybrid striped bass (Morone chrysops??Morone saxatilis) acclimated to fresh- or saltwater. Initially, hybrid striped bass were exposed to dietary Cu concentrations of 571, 785, and 1013 ??g Cu/g, along with a control (??? 5 ??g Cu/g), for 14 days in saltwater. Intestinal and liver Cu accumulated in a dose-dependent manner in fish exposed to increasing levels of dietary Cu. Chronic (42 days) experiments were then conducted to determine sub-lethal effects of aqueous, dietary, and combined aqueous and dietary Cu exposures to both freshwater- and saltwater-acclimated hybrid striped bass. Growth and Cu accumulation in the gill, intestine, and liver were measured. Although no significant effects were observed in fish exposed to waterborne Cu, those exposed through the diet accumulated significant liver and intestinal Cu but showed no significant change in growth. Overall, these results suggest that at the levels tested, exposure to elevated waterborne Cu did not cause significant long-term tissue Cu accumulation, whereas dietary Cu exposure caused significant liver and intestinal Cu accumulation in hybrid striped bass which was comparable in both freshwater and saltwater (15 g/L). ?? 2005 Elsevier Inc. All rights reserved.

  19. 75 FR 53953 - The National Saltwater Angler Registry Program; Designation of Exempted States for Anglers, Spear...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-02

    ... National Oceanic and Atmospheric Administration RIN 0648-XX66 The National Saltwater Angler Registry... Registry Program, 50 CFR subpart P, was published in the Federal Register on December 30, 2008. The final... numbers of the persons licensed or registered under a qualifying state license and/or registry program,...

  20. Characterising ontogenetic niche shifts in Nile crocodile using stable isotope (δ13C, δ15N) analyses of scute keratin.

    PubMed

    Radloff, Frans G T; Hobson, Keith A; Leslie, Alison J

    2012-09-01

    Nile crocodiles undergo a three to five order of magnitude increase in body size during their lifespan. This shift coincides with a change in resource and habitat use which influences the strength, type and symmetry of interactions with other species. Identifying size-specific crocodile groups displaying similar traits is important for conservation planning. Here, we illustrate how stable carbon (δ(13) C) and nitrogen (δ(15) N) isotope analysis of scute keratin, together with breakpoint modelling analysis can be used to characterise ontogenetic niche shifts. Using a sample set of 238 crocodiles from the Okavango Delta, Botswana (35-463 cm total length), we found prominent size-related changes in the scute keratin δ(13) C and δ(15) N profiles close to 40 and 119 cm snout-vent length. The first shift corroborated the findings of a traditional stomach-content study conducted on the same population at the same time, and the second conformed to known crocodile ecology. This approach can be used as a first approximation to identify size-specific groups within crocodile populations, and these can then be investigated further using isotopic or other methods.

  1. Effects of exposure of crocodiles to sublethal concentrations of Petroleum waste drilling fluid in the Niger Delta basin of Midwestern Nigeria.

    PubMed

    Ekpubeni, F A; Ekundayo, E O

    2002-06-01

    Static bioassay were carried out using two aquatic crocodiles (the short nosed crocodile, Osteolemus tetraspis and the Nile crocodile, Crocodilus niloticus) as test organisms in soft natural dilution water, with Petroleum waste drilling fluid as the test material, at 28 +/- 2 degrees C. Comparison of results for the control and different concentrations of the waste drilling fluid were made by means of the F-statistic method. Both crocodile species exhibited a high insensitivity to the undiluted waste drilling fluid and the different dilutions. Differences in concentration of waste drilling fluid did not influence the response of crocodiles to the potential toxicant. Percentage of deaths which was never greater than 0.2% in control tanks was not significantly different from that in test tanks where mortality values of organisms was typically 1.6% or less in most cases. There was a delay toxicant-induced mortality effect.

  2. Similarity of Crocodilian and Avian Lungs Indicates Unidirectional Flow Is Ancestral for Archosaurs.

    PubMed

    Farmer, C G

    2015-12-01

    Patterns of airflow and pulmonary anatomy were studied in the American alligator (Alligator mississippiensis), the black caiman (Melanosuchus niger), the spectacled caiman (Caiman crocodilus), the dwarf crocodile (Osteolaemus tetraspis), the saltwater crocodile (Crocodylus porosus), the Nile crocodile (Crocodylus niloticus), and Morelet's crocodile (Crocodylus moreletii). In addition, anatomy was studied in the Orinoco crocodile (Crocodylus intermedius). Airflow was measured using heated thermistor flow meters and visualized by endoscopy during insufflation of aerosolized propolene glycol and glycerol. Computed tomography and gross dissection were used to visualize the anatomy. In all species studied a bird-like pattern of unidirectional flow was present, in which air flowed caudad in the cervical ventral bronchus and its branches during both lung inflation and deflation and craniad in dorsobronchi and their branches. Tubular pathways connected the secondary bronchi to each other and allowed air to flow from the dorsobronchi into the ventrobronchi. No evidence for anatomical valves was found, suggesting that aerodynamic valves cause the unidirectional flow. In vivo data from the American alligator showed that unidirectional flow is present during periods of breath-holding (apnea) and is powered by the beating heart, suggesting that this pattern of flow harnesses the heart as a pump for air. Unidirectional flow may also facilitate washout of stale gases from the lung, reducing the cost of breathing, respiratory evaporative water loss, heat loss through the heat of vaporization, and facilitating crypsis. The similarity in structure and function of the bird lung with pulmonary anatomy of this broad range of crocodilian species indicates that a similar morphology and pattern of unidirectional flow were present in the lungs of the common ancestor of crocodilians and birds. These data suggest a paradigm shift is needed in our understanding of the evolution of this

  3. Saltwater wedge variation in a non-anthropogenic coastal karst aquifer influenced by a strong tidal range (Burren, Ireland)

    NASA Astrophysics Data System (ADS)

    Perriquet, Marie; Leonardi, Véronique; Henry, Tiernan; Jourde, Hervé

    2014-11-01

    Spatial and temporal changes in saltwater wedges in coastal karst aquifers are still poorly understood, largely due to complex mixing processes in these heterogeneous environments, but also due to anthropogenic forcing such as pumping, which commonly affect natural variations in wedges. The purpose of this study was first to characterize the hydrodynamic functioning of a karst aquifer in an oceanic temperate climate with little anthropogenic pressure but strongly influenced by a high tidal range and second, to evaluate the extent and movements of a saltwater wedge influenced by both the tide and the natural recharge of the aquifer. Variations in specific conductivity combined with water chemistry results from six boreholes and two lakes located in the Bell Harbour catchment (western Ireland) enabled us to assess the extent of the intrusion of the saltwater wedge into the aquifer as a function of both karst recharge and tidal movements at high/low and neap/spring tidal cycles. The marked spatial disparity of the saltwater wedge was analysed as a function of both the hydrodynamic and the structural properties of the karst aquifer. Results showed that the extent of the saltwater wedge depended not only on the intrinsic properties of the aquifer but also on the relative influence of the recharge and the tide on groundwater levels, which have opposite effects. Recharge in the Burren area throughout the year is large enough to prevent saltwater intruding more than about one kilometre from the shore. A strong tidal amplitude seems to be the motor of sudden saltwater intrusion observed in the aquifer near the shore while the position of the groundwater level seems to influence the intensity of the salinity increase. Competition between recharge and the tide thus controls the seawater inputs, hence explaining temporal and spatial changes in the saltwater wedge in this coastal karst aquifer.

  4. Dujardinascaris gigantea sp. n. (Nematoda: Ascaridida) from the critically endangered crocodile Alligator sinensis Fauvel (Reptilia: Crocodylia).

    PubMed

    Zhao, Jin-Hong; Li, Liang; Guo, Yan-Ning; Zhang, Lu-Ping

    2015-03-01

    The Chinese alligator Alligator sinensis Fauvel (Reptilia: Crocodylia) is considered as one of the most critically endangered species of the 23 extant crocodiles. However, our knowledge of the helminth parasites of this rare animal is completely lacking. During a helminthological survey of reptiles in China, we found a new ascaridoid nematode, Dujardinascaris gigantea sp. n. from A. sinensis. The morphology of D. gigantea sp. n. was studied using light and scanning electron microscopy. The new species was also characterised using molecular methods by sequencing and analysing the small ribosomal DNA (18S) and the second internal transcribed spacer (ITS-2).

  5. Aerobic intestinal flora of wild-caught African dwarf crocodiles Osteolaemus tetraspis.

    PubMed

    Huchzermeyer, F W; Henton, M M; Riley, J; Agnagna, M

    2000-09-01

    Intestinal contents were collected from wild-caught African dwarf crocodiles (Osteolaemus tetraspis) in 1993 and 1995 which were slaughtered at urban markets in the Congo Republic. The samples were kept frozen and brought back to Onderstepoort for aerobic culture. Out of 29 specimens, 33 species of bacteria and 20 species of fungi were isolated. The bacteria included three isolates of Salmonella and eight isolates of Escherichia coli, most of the latter being rough strains. The flora of individual specimens contained 1-5 bacterial and 0-5 fungal species. Neither Aeromonas hydrophila nor Edwardsiella tarda were isolated from any of the samples.

  6. Lead and cadmium associated with saltwater intrusion in a New Jersey aquifer system

    USGS Publications Warehouse

    Pucci, Amleto A.; Harriman, Douglas A.; Ervin, Elisabeth M.; Bratton, Lisa; Gordon, Alison

    1989-01-01

    The U.S. Geological Survey collected ground-water samples from the upper and middle aquifers of the Potomac-Raritan-Magothy aquifer system in a 400-square-mile area of New Jersey from 1984 through 1986. Concentrations of lead were greater than the U.S. Environmental Protection Agency maximum contaminant level (MCL) of 50 micrograms per liter in water from 16 to 239 wells. The concentrations of cadmium were greater than the MCL of 10 micrograms per liter in water from 10 to 241 wells. One-half of the wells that exceeded the lead MCL were in known areas of saltwater intrusion, as were all 10 wells that exceeded the cadmium MCL. The association of elevated concentrations of these metals with elevated concentrations of chloride indicates a mechanism related to saltwater intrusion.

  7. Changes in saltwater intrusion in the Biscayne aquifer, Hialeah-Miami Springs area, Dade County, Florida

    USGS Publications Warehouse

    Klein, Howard; Ratzlaff, Karl W.

    1989-01-01

    A lobe of salty groundwater that had intruded the Hialeah-Miami Springs area municipal well field, adjacent to the Miami and Tamiami Canals in Dade County, Florida, was stabilized after flow-regulation structures were installed in the canals in 1946. However, in 1971, the saltwater began to readvance toward the center of the well field because of water level declines caused by large increases in withdrawals during a near-record dry season. To better protect the well field, a temporary flow-regulation structure, constructed in 1971, in the Tamiami Canal was moved in 1976 to a permanent site, about 3,000 ft farther seaward; this converted that tidal reach of canal to a controlled reach under a sustained freshwater head. This water management procedure resulted in dilution of the intruding saltwater lobe and a marked concentration of its size even though large municipal withdrawals continued. (USGS)

  8. Lead and cadmium associated with saltwater intrusion in a New Jersey aquifer system

    SciTech Connect

    Pucci, A.A. Jr.; Gordon, A. ); Harriman, D.A. ); Ervin, E.M. ); Bratton, L. )

    1989-12-01

    The US Geological Survey collected ground-water samples from the upper and middle aquifers of the Potomac-Raritan-Magothy aquifer system in a 400-square-mile are of New Jersey from 1984 through 1986. Concentrations of lead were greater than the US Environmental Protection Agency maximum contaminant level (MCL) of 50 micrograms per liter in water from 16 to 239 wells. The concentrations of cadmium were greater than the MCL of 10 micrograms per liter in water from 10 to 241 wells. One-half of the wells that exceeded the lead MCL were in known areas of saltwater intrusion, as were all 10 wells that exceeded the cadmium MCL. The association of elevated concentrations of these metals with elevated concentrations of chloride indicates a mechanism related to saltwater intrusion.

  9. The history and evaluation of saltwater intrusion into a coastal aquifer in Mersin, Turkey.

    PubMed

    Demirel, Zeynel

    2004-03-01

    The Mersin-Kazanli region is a densely industrialized region. The factories and towns cover their water demand from groundwater. With the increased water demand, saltwater intrusion has occurred. The chloride concentration of the water samples from some wells has been analysed periodically since these wells were drilled. The results of these analyses and electrical conductivity measurements were used to show the history and development of saltwater intrusion up to the year 2000. The Cl(-) concentration of the water within the alluvial aquifer increased to over 3000 mg/l in 1999 and the wells were closed completely. In 2001 new wells were drilled more than 1 km away from the sea and old well field. With the results of the analyses conducted in 2001, the current groundwater quality was determined. The ground water is of the magnesium-calcium-bicarbonate type and this composition is controlled by the interaction of the water with the sediments of alluvial deposits.

  10. Stratigraphic controls on saltwater intrusion in the Dominguez Gap area of coastal Los Angeles

    USGS Publications Warehouse

    Edwards, B.D.; Ehman, K.D.; Ponti, D.J.; Reichard, E.G.; Tinsley, J.C.; Rosenbauer, R.J.; Land, M.

    2009-01-01

    The Los Angeles Basin is a densely populated coastal area that significantly depends on groundwater. A part of this groundwater supply is at risk from saltwater intrusion-the impetus for this study. High-resolution seismic-reflection data collected from the Los Angeles-Long Beach Harbor Complex have been combined with borehole geophysical and descriptive geological data from four nearby ??400-m-deep continuously cored wells and with borehole geophysical data from adjacent water and oil wells to characterize the Pliocene to Holocene stratigraphy of the Dominguez Gap coastal aquifer system. The new data are shown as a north-south, two- dimensional, sequence-stratigraphic model that is compared to existing lithostratigraphic models of the Los Angeles Basin in an attempt to better understand pathways of saltwater intrusion into coastal aquifers. Intrusion of saltwater into the coastal aquifer system generally is attributed to over-pumping that caused the hydraulic gradient to reverse during the mid-1920s. Local water managers have used the existing lithostratigraphic model to site closely spaced injection wells of freshwater (barrier projects) attempting to hydraulically control the saltwater intrusion. Improved understanding of the stratigraphic relationships can guide modifications to barrier design that will allow more efficient operation. Allostratigraphic nomenclature is used to define a new sequence-stratigraphic model for the area because the existing lithostratigraphic correlations that have been used to define aquifer systems are shown not to be time-correlative. The youngest sequence, the Holocene Dominguez sequence, contains the Gaspur aquifer at its base. The Gaspur aquifer is intruded with saltwater and consists of essentially flat-lying gravelly sands deposited by the ancestral Los Angeles River as broad channels that occupied a paleovalley incised into the coastal plain during the last glacio-eustatic highstand. The underlying sequences are deformed into

  11. Effects of subfornical organ extracts on salt-water balance in the rat

    NASA Technical Reports Server (NTRS)

    Summy-Long, J. Y.; Crawford, I. L.; Severs, W. B.

    1976-01-01

    The subfornical organ (SFO) is a circumventricular structure located at the junction of the lamina terminalis and the tela choroidea of the third cerebral ventricle. SFO is histologically regarded as a neurosecretory structure, although the physiological effects or biochemical nature of such secretions are not yet ascertained. Results are presented for an experimental study designed to determine whether SFO extracts alter parameters associated with salt-water balance in the rat. The data obtained support the conclusion that SFO contains some water-soluble substance(s), easily released by incubation, dialyzable and heat stable, which influences the salt-water balance after injection into ventricular cerebrospinal fluid. Whether other brain tissues or plasma contains the same or similar material is not yet convincingly established. The observation that one or more active constituents are easily released from SFO upon incubation in potassium-enriched medium may be of value.

  12. Utilization of a saltwater-marsh ecosystem for the management of seafood-processing wastewater

    SciTech Connect

    Not Available

    1986-10-01

    The report presents the results of a cooperative study that examined the potential for using a saltwater wetland to manage seafood-processing wastewater. An irregularly flooded black needlerush (Juncus roemerianus) marsh located at Point aux Pins in coastal Alabama was selected for the study. The study determined that the application of seafood-processing wastewater to the marsh affected a number of the marsh's water-quality characteristics in direct relation to the wastewater loading rate. However, monitoring of the marsh flora and fauna showed virtually no impact at any of the experimental loading rates. As a result of the study a number of design and loading criteria are suggested for any future projects involving wastewater discharges to saltwater wetlands.

  13. Behavioral responses of Magellanic Penguins (Spheniscus magellanicus) (Foster) to saltwater versus freshwater.

    PubMed

    Reisfeld, Laura; Moraes, Kaue; Spaulussi, Lygia; Cardoso, Ricardo Cesar; Ippolito, Laura; Gutierrez, Rafael; Silvatti, Bruna; Pizzutto, Cristiane Schilbach

    2013-01-01

    The most common penguin species found along the coast of Brazil is the Magellanic Penguin (Spheniscus magellanicus). These penguins spend most of their time foraging for food in the oceans. This information is vital to the maintenance of this species in captivity. The goal of this study was to evaluate the behavioral response of a group of Magellanic Penguins (S. magellanicus) in two different conditions of water--fresh and salt. The work was divided into two phases. First, animals were kept in enclosures with access to freshwater. Then they were housed with access to saltwater. Behaviors were recorded by scan sampling per interval of time, totaling 7,200 records for each animal. The results show that the use of saltwater for this group of animals kept in captivity was more effective for increasing the time the animals spent in the water, increasing foraging behavior, stimulating swimming, and providing display of typical behaviors of the species, showing that access to a saltwater environment is an important tool in trying to provide well-being for this species in captivity.

  14. Wetting and evaporation of salt-water nanodroplets: A molecular dynamics investigation

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Borg, Matthew K.; Sefiane, Khellil; Reese, Jason M.

    2015-11-01

    We employ molecular dynamics simulations to study the wetting and evaporation of salt-water nanodroplets on platinum surfaces. Our results show that the contact angle of the droplets increases with the salt concentration. To verify this, a second simulation system of a thin salt-water film on a platinum surface is used to calculate the various surface tensions. We find that both the solid-liquid and liquid-vapor surface tensions increase with salt concentration and as a result these cause an increase in the contact angle. However, the evaporation rate of salt-water droplets decreases as the salt concentration increases, due to the hydration of salt ions. When the water molecules have all evaporated from the droplet, two forms of salt crystals are deposited, clump and ringlike, depending on the solid-liquid interaction strength and the evaporation rate. To form salt crystals in a ring, it is crucial that there is a pinned stage in the evaporation process, during which salt ions can move from the center to the rim of the droplets. With a stronger solid-liquid interaction strength, a slower evaporation rate, and a higher salt concentration, a complete salt crystal ring can be deposited on the surface.

  15. Wetting and evaporation of salt-water nanodroplets: A molecular dynamics investigation.

    PubMed

    Zhang, Jun; Borg, Matthew K; Sefiane, Khellil; Reese, Jason M

    2015-11-01

    We employ molecular dynamics simulations to study the wetting and evaporation of salt-water nanodroplets on platinum surfaces. Our results show that the contact angle of the droplets increases with the salt concentration. To verify this, a second simulation system of a thin salt-water film on a platinum surface is used to calculate the various surface tensions. We find that both the solid-liquid and liquid-vapor surface tensions increase with salt concentration and as a result these cause an increase in the contact angle. However, the evaporation rate of salt-water droplets decreases as the salt concentration increases, due to the hydration of salt ions. When the water molecules have all evaporated from the droplet, two forms of salt crystals are deposited, clump and ringlike, depending on the solid-liquid interaction strength and the evaporation rate. To form salt crystals in a ring, it is crucial that there is a pinned stage in the evaporation process, during which salt ions can move from the center to the rim of the droplets. With a stronger solid-liquid interaction strength, a slower evaporation rate, and a higher salt concentration, a complete salt crystal ring can be deposited on the surface.

  16. Modeling saltwater upconing in a freshwater aquifer in south-central Kansas

    USGS Publications Warehouse

    Ma, T.-S.; Sophocleous, M.; Yu, Y.-S.; Buddemeier, R.W.

    1997-01-01

    The Great Bend Prairie freshwater alluvial aquifer in south-central Kansas overlies a bedrock brine aquifer of Permian age. The continuous extraction of freshwater mainly for irrigation in this area has accelerated the upward movement of the saltwater, resulting in the deterioration of water quality. Predicting saltwater upconing is critical for maintaining a long-term supply of water of good quality to the Groundwater Management District No. 5. This paper uses a numerical model to predict the effect of saltwater upconing on the salinity of pumped water. A sensitivity analysis was conducted for estimating the effects of uncertainties in model parameters on the numerical results. The most important factors affecting the salinity of discharged water are found to be the location and nature of clay layers in the aquifer, the pumping rate, the location of the well screen, and the hydraulic conductivities of the medium. The effect of uncertainties in aquifer porosity and dispersivity on salinity is appreciable but not substantial, whereas that of recharge from precipitation in the study area is relatively insignificant. In addition, a numerical model based on the field conditions observed at the Siefkes site was constructed and calibrated to reproduce and project the variation of measured water levels and discharged groundwater concentration. Finally, a number of practical management recommendations based on this study are presented.

  17. "Lyle, Lyle, Crocodile": A New Musical Based on the Books by Bernard Waber. Cue Sheet for Teachers.

    ERIC Educational Resources Information Center

    Selwyn, Karen P.

    This performance guide is designed for teachers to use with students before and after a performance of "Lyle, Lyle, Crocodile," a musical based on the books by Bernard Waber, with book by Michael Slade, music by David Evans, and lyrics by Mindi Dickstein. The guide, called a "Cuesheet," contains four activity sheets for use in…

  18. Crocodile-inspired dome-shaped pressure receptors for passive hydrodynamic sensing.

    PubMed

    Kanhere, Elgar; Wang, Nan; Kottapalli, Ajay Giri Prakash; Asadnia, Mohsen; Subramaniam, Vignesh; Miao, Jianmin; Triantafyllou, Michael

    2016-08-22

    Passive mechanosensing is an energy-efficient and effective recourse for autonomous underwater vehicles (AUVs) for perceiving their surroundings. The passive sensory organs of aquatic animals have provided inspiration to biomimetic researchers for developing underwater passive sensing systems for AUVs. This work is inspired by the 'integumentary sensory organs' (ISOs) which are dispersed on the skin of crocodiles and are equipped with slowly adapting (SA) and rapidly adapting (RA) receptors. ISOs assist crocodiles in locating the origin of a disturbance, both on the water surface and under water, thereby enabling them to hunt prey even in a dark environment and turbid waters. In this study, we construct SA dome receptors embedded with microelectromechanical systems (MEMS) piezoresistive sensors to measure the steady-state pressures imparted by flows and RA dome receptors embedded with MEMS piezoelectric sensors to detect oscillatory pressures in water. Experimental results manifest the ability of SA and RA dome receptors to sense the direction of steady-state flows and oscillatory disturbances, respectively. As a proof of concept, the SA domes are tested on the hull of a kayak under various pressure variations owing to different types of movements of the hull. Our results indicate that the dome receptors are capable of discerning the angle of attack and speed of the flow.

  19. High connectivity of the crocodile shark between the Atlantic and Southwest Indian Oceans: highlights for conservation.

    PubMed

    da Silva Ferrette, Bruno Lopes; Mendonça, Fernando Fernandes; Coelho, Rui; de Oliveira, Paulo Guilherme Vasconcelos; Hazin, Fábio Hissa Vieira; Romanov, Evgeny V; Oliveira, Claudio; Santos, Miguel Neves; Foresti, Fausto

    2015-01-01

    Among the various shark species that are captured as bycatch in commercial fishing operations, the group of pelagic sharks is still one of the least studied and known. Within those, the crocodile shark, Pseudocarcharias kamoharai, a small-sized lamnid shark, is occasionally caught by longline vessels in certain regions of the tropical oceans worldwide. However, the population dynamics of this species, as well as the impact of fishing mortality on its stocks, are still unknown, with the crocodile shark currently one of the least studied of all pelagic sharks. Given this, the present study aimed to assess the population structure of P. kamoharai in several regions of the Atlantic and Indian Oceans using genetic molecular markers. The nucleotide composition of the mitochondrial DNA control region of 255 individuals was analyzed, and 31 haplotypes were found, with an estimated diversity Hd = 0.627, and a nucleotide diversity π = 0.00167. An analysis of molecular variance (AMOVA) revealed a fixation index ΦST = -0.01118, representing an absence of population structure among the sampled regions of the Atlantic Ocean, and between the Atlantic and Indian Oceans. These results show a high degree of gene flow between the studied areas, with a single genetic stock and reduced population variability. In panmictic populations, conservation efforts can be concentrated in more restricted areas, being these representative of the total biodiversity of the species. When necessary, this strategy could be applied to the genetic maintenance of P. kamoharai.

  20. High Connectivity of the Crocodile Shark between the Atlantic and Southwest Indian Oceans: Highlights for Conservation

    PubMed Central

    da Silva Ferrette, Bruno Lopes; Mendonça, Fernando Fernandes; Coelho, Rui; de Oliveira, Paulo Guilherme Vasconcelos; Hazin, Fábio Hissa Vieira; Romanov, Evgeny V.; Oliveira, Claudio; Santos, Miguel Neves; Foresti, Fausto

    2015-01-01

    Among the various shark species that are captured as bycatch in commercial fishing operations, the group of pelagic sharks is still one of the least studied and known. Within those, the crocodile shark, Pseudocarcharias kamoharai, a small-sized lamnid shark, is occasionally caught by longline vessels in certain regions of the tropical oceans worldwide. However, the population dynamics of this species, as well as the impact of fishing mortality on its stocks, are still unknown, with the crocodile shark currently one of the least studied of all pelagic sharks. Given this, the present study aimed to assess the population structure of P. kamoharai in several regions of the Atlantic and Indian Oceans using genetic molecular markers. The nucleotide composition of the mitochondrial DNA control region of 255 individuals was analyzed, and 31 haplotypes were found, with an estimated diversity Hd = 0.627, and a nucleotide diversity π = 0.00167. An analysis of molecular variance (AMOVA) revealed a fixation index ΦST = -0.01118, representing an absence of population structure among the sampled regions of the Atlantic Ocean, and between the Atlantic and Indian Oceans. These results show a high degree of gene flow between the studied areas, with a single genetic stock and reduced population variability. In panmictic populations, conservation efforts can be concentrated in more restricted areas, being these representative of the total biodiversity of the species. When necessary, this strategy could be applied to the genetic maintenance of P. kamoharai. PMID:25689742

  1. Simulation of saltwater movement in the Floridan aquifer system, Hilton Head Island, South Carolina

    USGS Publications Warehouse

    Bush, Peter W.

    1988-01-01

    Freshwater to supply Hilton Head Island, S.C., is obtained from the upper permeable zone of the Upper Floridan aquifer. Long-term pumping at Savannah, Ga., and the steadily increasing pumping on Hilton Head Island, have lowered Upper Floridan heads near the center of the island from about 10 feet above sea level to about 6 to 7 feet below sea level. The seaward hydraulic gradient that existed before pumping began has been reversed, thus increasing the potential for saltwater intrusion. Simulations of predevelopment, recent, and future ground-water flow in the Floridan aquifer system beneath the north end of Hilton Head Island and Port Royal Sound are presented. A finite-element model for fluid-density-dependent ground-water flow and solute transport was used in cross section. The general configuration of the simulated predevelopment flowfield is typical of a coastal aquifer having a seaward gradient in the freshwater. The freshwater flows toward Port Royal Sound over an intruding wedge of saltwater. The simulated flowfield at the end of 1983 shows that ground water in the Floridan aquifer system beneath most of Hilton Head Island has reversed its predevelopment direction and is moving toward Savannah. The distribution of chloride concentrations, based on simulation at the end of 1983, is about the same as the predevelopment distribution of chloride concentrations obtained from simulation. Results of two 50-year simulations from 1983 to 2034 suggest that there will be no significant threat of saltwater intrusion into the upper permeable zone of the Upper Floridan aquifer if heads on Hilton Head Island remain at current levels for the next 45 to 50 years. However, if head decline continues at the historical rate, any flow that presently occurs from the north end of the island toward Port Royal Sound will cease, allowing lateral intrusion of saltwater to proceed. Even under these conditions, chloride concentrations in the upper permeable zone of the Upper Floridan

  2. Position of the freshwater-saltwater interface in a coastal confined aquifer

    NASA Astrophysics Data System (ADS)

    Evans, T. B.; White, S. M.; Wilson, A. M.

    2014-12-01

    Delineating the position of the freshwater-saltwater interface is necessary for understanding submarine groundwater discharge and for assessing risks associated with saltwater intrusion, but most studies of the freshwater-saltwater interface focus on shallow surficial aquifers. Groundwater dynamics in coastal aquifers at depths greater than 5 m below land surface have rarely been assessed. The freshwater-saltwater interface in deeper confined aquifers is frequently positioned offshore, where it is difficult to locate or study. Our investigation was located at North Inlet, a wide, intertidal wetland southeast of Georgetown, SC. This site was ideal for studying the freshwater-saltwater interface at the embayment scale because the first major confined aquifer under the wetlands was accessible. Using electrical resistivity tomography, we were able to image the upper 20 to 30 m of sediment, including the first major confined aquifer. At North Inlet a 75 km2 island is bounded by extensive marsh and relict and modern barrier islands extending ~10 km seaward to the Atlantic Ocean. Surface and groundwater salinity throughout the marsh is 35 ppt. In order to get maximum depth penetration, surveys were conducted along dry land on the island and marsh surface with 10 m electrode spacing. Measured apparent resistivity varied in all surveys. A 20 Ohm-m resistivity layer at 25 m depth suggests that freshwater extends 335 m from the mainland. The presence of this freshwater indicates regional groundwater flow under the marsh or high rates of infiltration during precipitation events. Groundwater was saline to brackish (~10 Ohm-m) 1 km further out into the marsh at the next relict beach ridge at depths of 20 to 30 m. These results indicate that embayment scale groundwater flow plays an important role in providing low salinity pore-water to the marsh from beneath. The presence of fresh/brackish groundwater hundreds of meters from the mainland suggests that coastal confined aquifers

  3. Chlorinated, brominated, and fluorinated organic pollutants in Nile crocodile eggs from the Kruger National Park, South Africa.

    PubMed

    Bouwman, Hindrik; Booyens, Paul; Govender, Danny; Pienaar, Danie; Polder, Anuschka

    2014-06-01

    Repeated annual episodes of Nile crocodile deaths in two isolated areas of the Kruger National Park prompted the investigation of possible organohalogen pollutant involvement. Crocodile eggs were collected close to one of the mortality sites (Gorge) as well as from a crocodile farm (CF) as reference. ∑DDT was significantly higher in Gorge (450ng/g wm) than in CF eggs (85ng/g wet mass). Percentage DDT of ∑DDT was significantly higher in CF (14 per cent) than in Gorge eggs (5 per cent). Mean ∑DDT was almost 70 times higher than mean ∑PCB in Gorge eggs. HCB, β-HCH, mirex, brominated flame retardants (BFRs), and perfluorinated compounds (PFCs) occurred at lower concentrations. We believe that the BFR and PFCs data represent the first published results for any crocodile egg. Thickening of the outer eggshell layer of Gorge eggs was significantly associated with higher concentrations of ∑DDT. Concentrations of ∑DDT and other pollutants were in the same range as eggs from elsewhere, where there were no mortalities. Concentrations of ∑DDT in eggs from healthy Australian crocodiles were of the same orders of magnitude as the current study, making it highly unlikely that the concentrations of pollutants measured in the present study would have caused or substantially contributed towards the mortalities observed. Concerns about reproduction and behaviour remain. As large predators, crocodilians are at the apex of the freshwater aquatic food web. More research is needed to guide measures to manage African freshwater systems so that it will also sustainably accommodate these large, long-lived animals.

  4. Hydrogeology and extent of saltwater intrusion on Manhasset Neck, Nassau County, New York

    USGS Publications Warehouse

    Stumm, Frederick; Lange, Andrew D.; Candela, J.L.

    2002-01-01

    Manhasset Neck, a peninsula on the northern shore of Long Island, N.Y., is underlain by unconsolidated deposits that form a sequence of aquifers and confning units. Ground water at several public-supply wells has been affected by the intrusion of saltwater from the surrounding embayments (Manhasset Bay, Long Island Sound, Hempstead Harbor). Twenty-two boreholes were drilled during 1992-96 for the collection of hydrogeologic, geochemical, and geophysical data to delineate the subsurface geology and the extent of saltwater intrusion within the peninsula. A series of continuous high-resolution seismic- reflection surveys was completed in 1993 and 1994 to delineate the character and extent of the hydrogeologic deposits beneath the embayments surrounding Manhasset Neck.The new drill-core data indicate two hydrogeologic units--the North Shore aquifer and the North Shore confining unit--where the Lloyd aquifer, Raritan confining unit, and the Magothy aquifer have been completely removed by glacial erosion.Water levels at selected observation wells were measured quarterly throughout the study. These data, and continuous water-level records, indicate that (1) the upper glacial (water-table) and Magothy aquifers are hydraulically connected and that their water levels do not respond to tidal fluctuations, and (2) the Lloyd and North Shore aquifers also are hydraulically connected, but their water levels do respond to pumping and tidal fluctuations.Offshore seismic-reflection surveys in the surrounding embayments, and drill-core samples, indicate at least four glacially eroded buried valleys with subhorizontal, parallel reflectors indicative of draped bedding that is interpreted as infilling by silt and clay. The buried valleys (1) truncate the surrounding coarse-grained deposits, (2) are asymmetrical and steep sided, (3) trend northwest-southeast, (4) are 2 to 4 miles long and about 1 mile wide, and (5) extend to more than 400 feet below sea level.Water from 12 public

  5. Hydrogeology and extent of saltwater intrusion on Manhasset Neck, Nassau County, New York

    USGS Publications Warehouse

    Stumm, Frederick; Lange, Andrew D.; Candela, J.L.

    2002-01-01

    Manhasset Neck, a peninsula on the northern shore of Long Island, N.Y., is underlain by unconsolidated deposits that form a sequence of aquifers and confning units. Ground water at several public-supply wells has been affected by the intrusion of saltwater from the surrounding embayments (Manhasset Bay, Long Island Sound, Hempstead Harbor). Twenty-two boreholes were drilled during 1992-96 for the collection of hydrogeologic, geochemical, and geophysical data to delineate the subsurface geology and the extent of saltwater intrusion within the peninsula. A series of continuous high-resolution seismic- reflection surveys was completed in 1993 and 1994 to delineate the character and extent of the hydrogeologic deposits beneath the embayments surrounding Manhasset Neck. The new drill-core data indicate two hydrogeologic units--the North Shore aquifer and the North Shore confining unit--where the Lloyd aquifer, Raritan confining unit, and the Magothy aquifer have been completely removed by glacial erosion. Water levels at selected observation wells were measured quarterly throughout the study. These data, and continuous water-level records, indicate that (1) the upper glacial (water-table) and Magothy aquifers are hydraulically connected and that their water levels do not respond to tidal fluctuations, and (2) the Lloyd and North Shore aquifers also are hydraulically connected, but their water levels do respond to pumping and tidal fluctuations. Offshore seismic-reflection surveys in the surrounding embayments, and drill-core samples, indicate at least four glacially eroded buried valleys with subhorizontal, parallel reflectors indicative of draped bedding that is interpreted as infilling by silt and clay. The buried valleys (1) truncate the surrounding coarse-grained deposits, (2) are asymmetrical and steep sided, (3) trend northwest-southeast, (4) are 2 to 4 miles long and about 1 mile wide, and (5) extend to more than 400 feet below sea level. Water from 12 public

  6. Optimal management of saltwater intrusion in the coastal aquifer of Malia, Crete (Greece), using particle swarm optimization

    NASA Astrophysics Data System (ADS)

    Karatzas, George P.; Dokou, Zoi

    2015-09-01

    Saltwater intrusion is a common phenomenon in coastal aquifers that can affect the quality of water intended for drinking and irrigation purposes. In order to provide sustainable management options for the coastal aquifer of Malia, located on the Greek island of Crete, a weighted multi-objective optimization methodology is employed. The methodology involves use of the particle swarm optimization algorithm combined with groundwater modelling. The sharp-interface approximation combined with the Ghyben-Herztberg equation is used to estimate the saltwater-intrusion front location. The prediction modelling results show that under the current pumping strategies (over-exploitation), the saltwater-intrusion front will continue to move inland, posing a serious threat to the groundwater quality. The management goal is to maximize groundwater withdrawal rates in the existing pumping wells while inhibiting the saltwater-intrusion front at locations closer to the coastal zone. This is achieved by requiring a minimum hydraulic-head value at pre-selected observation locations. In order to control the saltwater intrusion, a large number of pumping wells must be deactivated and alternative sources of water need to be considered.

  7. Saltwater intrusion in the surficial aquifer system of the Big Cypress Basin, southwest Florida, and a proposed plan for improved salinity monitoring

    USGS Publications Warehouse

    Prinos, Scott T.

    2013-01-01

    The installation of drainage canals, poorly cased wells, and water-supply withdrawals have led to saltwater intrusion in the primary water-use aquifers in southwest Florida. Increasing population and water use have exacerbated this problem. Installation of water-control structures, well-plugging projects, and regulation of water use have slowed saltwater intrusion, but the chloride concentration of samples from some of the monitoring wells in this area indicates that saltwater intrusion continues to occur. In addition, rising sea level could increase the rate and extent of saltwater intrusion. The existing saltwater intrusion monitoring network was examined and found to lack the necessary organization, spatial distribution, and design to properly evaluate saltwater intrusion. The most recent hydrogeologic framework of southwest Florida indicates that some wells may be open to multiple aquifers or have an incorrect aquifer designation. Some of the sampling methods being used could result in poor-quality data. Some older wells are badly corroded, obstructed, or damaged and may not yield useable samples. Saltwater in some of the canals is in close proximity to coastal well fields. In some instances, saltwater occasionally occurs upstream from coastal salinity control structures. These factors lead to an incomplete understanding of the extent and threat of saltwater intrusion in southwest Florida. A proposed plan to improve the saltwater intrusion monitoring network in the South Florida Water Management District’s Big Cypress Basin describes improvements in (1) network management, (2) quality assurance, (3) documentation, (4) training, and (5) data accessibility. The plan describes improvements to hydrostratigraphic and geospatial network coverage that can be accomplished using additional monitoring, surface geophysical surveys, and borehole geophysical logging. Sampling methods and improvements to monitoring well design are described in detail. Geochemical analyses

  8. Groundwater as an emergency source for drought mitigation in the Crocodile River catchment, South Africa

    NASA Astrophysics Data System (ADS)

    Mussá, F. E. F.; Zhou, Y.; Maskey, S.; Masih, I.; Uhlenbrook, S.

    2014-03-01

    Global climate change has received much attention worldwide in the scientific as well as in the political community, indicating that changes in precipitation, extreme droughts and floods may threaten increasingly many regions. Drought is a natural phenomenon that may cause social, economical and environmental damages to the society. In this study, we assess the drought intensity and severity and the groundwater potential to be used as a supplement source of water to mitigate drought impacts in the Crocodile River catchment, a water-stressed sub-catchment of the Incomati River catchment in South Africa. The research methodology consists mainly of three parts. First, the spatial and temporal variation of the meteorological and hydrological drought severity and intensity over the catchment were evaluated. The Standardized Precipitation Index (SPI) was used to analyse the meteorological drought and the Standardized Runoff Index (SRI) was used for the hydrological drought. Second, the water deficit in the catchment during the drought period was computed using a simple water balance method. Finally, a groundwater model was constructed in order to assess the feasibility of using groundwater as an emergency source for drought impact mitigation. Results show that the meteorological drought severity varies accordingly with the precipitation; the low rainfall areas are more vulnerable to severe meteorological droughts (lower and upper crocodile). Moreover, the most water stressed sub-catchments with high level of water uses but limited storage, such as the Kaap located in the middle catchment and the Lower Crocodile sub-catchments are those which are more vulnerable to severe hydrological droughts. The analysis of the potential groundwater use during droughts showed that a deficit of 97 Mm3 yr-1 could be supplied from groundwater without considerable adverse impacts on the river base flow and groundwater storage. Abstraction simulations for different scenarios of extremely

  9. Groundwater as an emergency source for drought mitigation in the Crocodile River catchment, South Africa

    NASA Astrophysics Data System (ADS)

    Mussá, F. E. F.; Zhou, Y.; Maskey, S.; Masih, I.; Uhlenbrook, S.

    2015-02-01

    Global climate change has received much attention worldwide in the scientific as well as in the political community, indicating that changes in precipitation, extreme droughts and floods may increasingly threaten many regions. Drought is a natural phenomenon that causes social, economical and environmental damage to society. In this study, we assess the drought intensity and severity and the groundwater potential to be used as a supplementary source of water to mitigate drought impacts in the Crocodile River catchment, a water-stressed sub-catchment of the Incomati River catchment in South Africa. The research methodology consists of three parts. First, the spatial and temporal variation of the meteorological and hydrological drought severity and intensity over the catchment were evaluated. The Standardized Precipitation Index (SPI) was used to analyse the meteorological drought and the Standardized Runoff Index (SRI) was used for the hydrological drought. Second, the water deficit in the catchment during the drought period was computed using a simple water balance method. Finally, a groundwater model was constructed in order to assess the feasibility of using groundwater as an emergency source for drought impact mitigation. Results show that the low-rainfall areas are more vulnerable to severe meteorological droughts (lower and upper crocodile). Moreover, the most water stressed sub-catchments with high level of water uses but limited storage, such as the Kaap located in the middle catchment and the Lower Crocodile sub-catchments, are more vulnerable to severe hydrological droughts. The analysis of the potential groundwater use during droughts showed that a deficit of 97 Mm3 yr-1 could be supplied from groundwater without considerable adverse impacts on the river base flow and groundwater storage. Abstraction simulations for different scenarios of extremely severe droughts reveal that it is possible to use groundwater to cope with the droughts in the catchment

  10. Modeling the fate and transport of saltwater discharged into a well during a tsunami event

    NASA Astrophysics Data System (ADS)

    Goswami, R. R.; Villholth, K. G.; Clement, P. T.

    2007-12-01

    The 2004 Asian tsunami caused considerable contamination of groundwater resources in Sri Lanka. Open wells are widely used in the coastal areas of Sri Lanka for accessing potable water and sea water inundation through these open wells was potentially a major source of groundwater contamination. Various organizations tried to remediate the contamination in these wells through pumping. However, these efforts were ill-coordinated and in most cases the pumping was done without any technical information or scientific basis. There were no guidelines available for pumping wells after a saltwater event at that time. Therefore, there is a strong need for understanding the saltwater migration processes in order to develop a set of guidelines for well cleanup. Our project, funded by international agencies was jointly conducted by a multi-disciplinary team of international scientists. We conducted field and laboratory experiments by simulating tsunami-type inundation events in wells. The field experiments were conducted at a pristine location, unaffected by the tsunami, on the west coast of Sri Lanka. Field experiments are hard to analyze without a supporting investigation, therefore we performed laboratory experiments. Since all real world scenarios cannot be modeled through physical experiments due to resource (time, money and manpower) constraints, well calibrated numerical models are often used to simulate various different cases. The widely used numerical code, SEAWAT, was used to numerically simulate the laboratory experiments and to develop a well-calibrated numerical model. The numerical model was further used to perform a scenario analysis by varying the hydraulic parameters. In the presentation we will discuss the results of the investigations conducted by the team based in the USA that assisted in the development of physical and numerical experiments. In particular, we will present the effect of varying hydraulic parameters on the fate and transport of saltwater

  11. Theory and application of an approximate model of saltwater upconing in aquifers

    USGS Publications Warehouse

    McElwee, C.; Kemblowski, M.

    1990-01-01

    Motion and mixing of salt water and fresh water are vitally important for water-resource development throughout the world. An approximate model of saltwater upconing in aquifers is developed, which results in three non-linear coupled equations for the freshwater zone, the saltwater zone, and the transition zone. The description of the transition zone uses the concept of a boundary layer. This model invokes some assumptions to give a reasonably tractable model, considerably better than the sharp interface approximation but considerably simpler than a fully three-dimensional model with variable density. We assume the validity of the Dupuit-Forchheimer approximation of horizontal flow in each layer. Vertical hydrodynamic dispersion into the base of the transition zone is assumed and concentration of the saltwater zone is assumed constant. Solute in the transition zone is assumed to be moved by advection only. Velocity and concentration are allowed to vary vertically in the transition zone by using shape functions. Several numerical techniques can be used to solve the model equations, and simple analytical solutions can be useful in validating the numerical solution procedures. We find that the model equations can be solved with adequate accuracy using the procedures presented. The approximate model is applied to the Smoky Hill River valley in central Kansas. This model can reproduce earlier sharp interface results as well as evaluate the importance of hydrodynamic dispersion for feeding salt water to the river. We use a wide range of dispersivity values and find that unstable upconing always occurs. Therefore, in this case, hydrodynamic dispersion is not the only mechanism feeding salt water to the river. Calculations imply that unstable upconing and hydrodynamic dispersion could be equally important in transporting salt water. For example, if groundwater flux to the Smoky Hill River were only about 40% of its expected value, stable upconing could exist where

  12. Saltwater intrusion in the Floridan aquifer, coastal Citrus and Hernando Counties, Florida, 1975

    USGS Publications Warehouse

    Mills, L.R.; Ryder, Paul D.

    1977-01-01

    The coastal parts of Citrus and Hernando Counties, Fla., are undergoing extensive urban development along U.S. Highway 19. The Floridan aquifer, a thick sequence of limestone and dolomite , is the principal source of water supply for the coastal parts of these two counties. The construction of canals that penetrate the Floridan aquifer, deficient rainfall during 1964-75, and pumping of ground water, have caused saltwater to intrude the aquifer. A map shows the inland extend of that intrusion as of 1975. The report is based on field data collected in 1964, 1973, and 1975. (Woodard-USGS)

  13. Bibliography on the occurrence and intrusion of saltwater in aquifers along the Atlantic Coast of the United States

    USGS Publications Warehouse

    Barlow, Paul M.; Wild, Emily C.

    2002-01-01

    Freshwater aquifers along the Atlantic coast of the United States are vulnerable to the intrusion of saltwater from saline waters that bound the aquifers along their seaward margins. Incidences of saltwater intrusion have been documented along the Atlantic coast for more than 100 years. This report provides a bibliography of published literature relating to the occurrence and intrusion of saltwater along the Atlantic coast of the United States, including all of the coastal States from Maine to Florida (including the coast of Florida along the Gulf of Mexico). The bibliography contains 549 references that date from 1896 to 2001. The bibliography contains references to books, journal articles, and government and other technical reports and maps that could be readily obtained through a scientific library. Conference papers and abstracts, unpublished manuscripts, publications in press, newspaper articles, consulting reports, and reports prepared by local or regional water companies or water districts are omitted from the bibliography.

  14. Size does matter: crocodile mothers react more to the voice of smaller offspring.

    PubMed

    Chabert, T; Colin, A; Aubin, T; Shacks, V; Bourquin, S L; Elsey, R M; Acosta, J G; Mathevon, N

    2015-10-23

    Parental care is widespread in Archosaurs (birds, crocodilians, dinosaurs and pterosaurs), and this group provides a useful model for the evolution of parent-offspring interactions. While offspring signalling has been well-studied in birds, the modulation of parental care in crocodilians remains an open question. Here we show that acoustic communication has a key role in the dynamics of crocodilian' mother-offspring relationships. We found embedded information about the emitter's size in juvenile calls of several species, and experimentally demonstrated that Nile crocodile mothers breeding in the wild are less receptive to the calls of larger juveniles. Using synthetized sounds, we further showed that female' reaction depends on call pitch, an important cue bearing size information. Changes in acoustic interactions may thus go with the break of maternal care as well as dispersal of juvenile crocodilians. This process could have characterized other archosaurs displaying rapid early growth such as dinosaurs and pterosaurs.

  15. Size does matter: crocodile mothers react more to the voice of smaller offspring

    PubMed Central

    Chabert, T.; Colin, A.; Aubin, T.; Shacks, V.; Bourquin, S. L.; Elsey, R. M.; Acosta, J. G.; Mathevon, N.

    2015-01-01

    Parental care is widespread in Archosaurs (birds, crocodilians, dinosaurs and pterosaurs), and this group provides a useful model for the evolution of parent-offspring interactions. While offspring signalling has been well-studied in birds, the modulation of parental care in crocodilians remains an open question. Here we show that acoustic communication has a key role in the dynamics of crocodilian’ mother-offspring relationships. We found embedded information about the emitter’s size in juvenile calls of several species, and experimentally demonstrated that Nile crocodile mothers breeding in the wild are less receptive to the calls of larger juveniles. Using synthetized sounds, we further showed that female’ reaction depends on call pitch, an important cue bearing size information. Changes in acoustic interactions may thus go with the break of maternal care as well as dispersal of juvenile crocodilians. This process could have characterized other archosaurs displaying rapid early growth such as dinosaurs and pterosaurs. PMID:26493940

  16. Geophysical characterization of saltwater intrusion in a coastal aquifer: The case of Martil-Alila plain (North Morocco)

    NASA Astrophysics Data System (ADS)

    Himi, Mahjoub; Tapias, Josefiina; Benabdelouahab, Sara; Salhi, Adil; Rivero, Luis; Elgettafi, Mohamed; El Mandour, Abdenabi; Stitou, Jamal; Casas, Albert

    2017-02-01

    Several factors can affect the quantity and the quality of groundwater resources, but in coastal aquifers seawater intrusion is often the most significant issue regarding freshwater supply. Further, saltwater intrusion is a worldwide issue because about seventy percent of the world's population lives in coastal regions. Generally, fresh groundwater not affected by saltwater intrusion is characterized by low salinity and therefore low electrical conductivity (EC) values. Consequently, high values of EC in groundwater along the coastline are usually associated to seawater intrusion. This effect is amplified if the coastal aquifer is overexploited with a subsequent gradual displacement of the freshwater-saltwater interface towards the continent. Delineation of marine intrusion in coastal aquifers has traditionally relied upon observation wells and collection of water samples. This approach may miss important hydrologic features related to saltwater intrusion in areas where access is difficult and where wells are widely spaced. Consequently, the scarcity of sampling points and sometimes their total absence makes the number of data available limited and most of the time not representative for mapping the spatial and temporal variability of groundwater salinity. In this study, we use a series of geophysical methods for characterizing the aquifer geometry and the extension of saltwater intrusion in the Martil-Alila coastal region (Morocco) as a complement to geological and hydrogeochemical data. For this reason, we carried out three geophysical surveys: Gravity, Electrical Resistivity and Frequency Domain Electromagnetic. The geometry of the basin has been determined from the interpretation of a detailed gravity survey. Electrical resistivity models derived from vertical electrical soundings allowed to characterize the vertical and the lateral extensions of aquifer formations. Finally, frequency domain electromagnetic methods allowed delineating the extension of the

  17. Analysis of ground-water flow and saltwater encroachment in the shallow aquifer system of Cape May County, New Jersey

    USGS Publications Warehouse

    Spitz, Frederick J.

    1998-01-01

    Cape May County, New Jersey, is on a natural peninsula that is virtually surrounded by saltwater. A calibrated quasi-three-dimensional sharp-interface model was used to simulate ground-water flow in the shallow aquifer system under two water-supply-development alternatives for a 30-year planning period. The alternatives involve modest increases in withdrawals in combination with desalination of brackish ground water or inland relocation of wells. Simulation results indicate that projected withdrawals for the two alternatives can be sustained without significant additional saltwater encroachment over the planning period.

  18. Groundwater transport and the freshwater-saltwater interface below sandy beaches

    NASA Astrophysics Data System (ADS)

    Evans, Tyler B.; Wilson, Alicia M.

    2016-07-01

    Current conceptual models for groundwater flow in beaches highlight an upper saline plume, which is separated from the lower salt wedge by a zone of brackish to fresh groundwater discharge. There is currently limited knowledge of what conditions allow an upper saline plume to exist and what factors control its formation. We used variable-density, saturated-unsaturated, transient groundwater flow models to investigate the configuration of the freshwater-saltwater interface in beaches with slopes varying from 0.1 to 0.01, in the absence of waves. We also varied hydraulic conductivity, dispersivity, tidal amplitude and inflow of fresh groundwater. The simulated salinity configuration of the freshwater-saltwater interfaces varied significantly. No upper saline plumes formed in any beach with hydraulic conductivities less than 10 m/d. The slope of the beach was also a significant control. Steeper beach faces allowed stronger upper saline plumes to develop. Median sediment grain size of the beach is strongly correlated to both beach slope and permeability, and therefore the development of an upper saline plume. Prior studies of groundwater flow and salinity in beaches have used a range of theoretical dispersivities and the appropriate values of dispersivity to be used to represent real beaches remains unclear. We found the upper saline plume to weaken with the use of larger values of dispersivity. Our results suggest that upper saline plumes do not form in all beaches and may be less common than previously considered.

  19. Ecotoxicity of engineered TiO2 nanoparticles to saltwater organisms: an overview.

    PubMed

    Minetto, D; Libralato, G; Volpi Ghirardini, A

    2014-05-01

    The innovative properties of nanomaterials make them suitable for various applications in many fields. In particular, TiO2 nanoparticles (nTiO2) are widely used in paints, in cosmetics and in sunscreens that are products accessible to the mass market. Despite the great increase in the use of such nanomaterials, there is a paucity of general information about their potential effects to the aquatic species, especially to saltwater ones. Moreover, the difficulties of determining the effective exposure scenario make the acquired information low comparable. In this work, questions about the complexity of the real exposure scenario determination are discussed. The state of the art, concerning the experimental activities with nTiO2 toward the saltwater organisms is firstly illustrated, providing statistical information about the different matrices, organisms and nanoparticles employed. A comparison of the nTiO2 ecotoxicity effects, grouped by taxonomic classes, is provided illustrating their relative experimental conditions. Findings show the need to develop specific protocols for toxicity tests with ENPs to control the variability of experimental conditions. Some advices are finally proposed for the future experimental activities.

  20. Managing saltwater intrusion in coastal arid regions and its societal implications for agriculture

    NASA Astrophysics Data System (ADS)

    Grundmann, Jens; Al-Khatri, Ayisha; Schütze, Niels

    2016-05-01

    Coastal aquifers in arid and semiarid regions are particularly at risk due to intrusion of salty marine water. Since groundwater is predominantly used in irrigated agriculture, its excessive pumping - above the natural rate of replenishment - strengthen the intrusion process. Using this increasingly saline water for irrigation, leads to a destruction of valuable agricultural resources and the economic basis of farmers and their communities. The limitation of resources (water and soil) in these regions requires a societal adaptation and change in behaviour as well as the development of appropriate management strategies for a transition towards stable and sustainable future hydrosystem states. Besides a description of the system dynamics and the spatial consequences of adaptation on the resources availability, the contribution combines results of an empirical survey with stakeholders and physically based modelling of the groundwater-agriculture hydrosystem interactions. This includes an analysis of stakeholders' (farmers and decision makers) behaviour and opinions regarding several management interventions aiming on water demand and water resources management as well as the thinking of decision makers how farmers will behave. In this context, the technical counter measures to manage the saltwater intrusion by simulating different groundwater pumping strategies and scenarios are evaluated from the economic and social point of view and if the spatial variability of the aquifer's hydrogeology is taken into consideration. The study is exemplarily investigated for the south Batinah region in the Sultanate of Oman, which is affected by saltwater intrusion into a coastal aquifer system due to excessive groundwater withdrawal for irrigated agriculture.

  1. Movement of the saltwater interface in the surficial aquifer system in response to hydrologic stresses and water-management practices, Broward County, Florida

    USGS Publications Warehouse

    Dausman, Alyssa M.; Langevin, Christian D.

    2005-01-01

    A study was conducted to evaluate the relation between water-level fluctuations and saltwater intrusion in Broward County, Florida. The objective was achieved through data collection at selected wells in Broward County and through the development of a variable-density ground-water flow model. The numerical model is representative of many locations in Broward County that contain a well field, control structure, canal, the Intracoastal Waterway, and the Atlantic Ocean. The model was used to simulate short-term movement (from tidal fluctuations to monthly changes) and long-term movement (greater than 10 years) of the saltwater interface resulting from changes in rainfall, well-field withdrawals, sea-level rise, and upstream canal stage. The SEAWAT code, which is a combined version of the computer codes, MODFLOW and MT3D, was used to simulate the complex variable-density flow patterns. Model results indicated that the canal, control structure, and sea level have major effects on ground-water flow. For periods greater than 10 years, the upstream canal stage controls the movement and location of the saltwater interface. If upstream canal stage is decreased by 1 foot (0.3048 meter), the saltwater interface takes 50 years to move inland and stabilize. If the upstream canal stage is then increased by 1 foot (0.3048 meter), the saltwater interface takes 90 years to move seaward and stabilize. If sea level rises about 48 centimeters over the next 100 year as predicted, then inland movement of the saltwater interface may cause well-field contamination. For periods less than 10 years, simulation results indicated that a 3-year drought with increased well-field withdrawals probably will not have long-term effects on the position of the saltwater interface in the Biscayne aquifer. The saltwater interface returns to its original position in less than 10 years. Model results, however, indicated that the interface location in the lower part of the surficial aquifer system takes

  2. Using transportation networks to inform valuation of water quality changes for saltwater recreation on Cape Cod, MA

    EPA Science Inventory

    Estimating the non-market value of beaches for saltwater recreation is complex. An individual’s preference for a beach depends on beach characteristics and perception. When choosing one beach over another, an individual balances these personal preferences with any additiona...

  3. Impact of sea-level rise on saltwater intrusion length into the coastal aquifer, Partido de La Costa, Argentina

    NASA Astrophysics Data System (ADS)

    Carretero, Silvina; Rapaglia, John; Bokuniewicz, Henry; Kruse, Eduardo

    2013-07-01

    The impact to water resources of a potential 1-m rise in sea level against the low-lying coast of Partido de La Costa, Argentina was modeled using two scenarios. The first scenario was calculated under the assumption of a constant lateral flux of freshwater. A constant water-table elevation was assumed in the second scenario. Maintaining the lateral flux of freshwater from the land (the first scenario) resulted in an approximately linear increase of the inland extent of saltwater intrusion with rising sea level; saltwater penetrated landward between 25 and 40 m. Meanwhile holding the water-table elevation constant (the second scenario), caused the movement of the saltwater interface to be non-linear. In this case, landward migration in excess of 200 m or more might be expected. The second scenario is more likely to be the situation in Partido de La Costa. The variation of hydrogeological parameters from north to south along the barrier conspire to make the southern reaches, where both the hydraulic conductivity and aquifer thickness are greater, more sensitive to saltwater intrusion from sea-level rise than the northern part of the barrier. These findings may be applicable to similar sandy coastal aquifers in other parts of the global coastline.

  4. Effect of eustatic sea-level changes on saltwater-freshwater relations in the Northern Atlantic Coastal Plain

    USGS Publications Warehouse

    Meisler, Harold; Leahy, P. Patrick; Knobel, LeRoy L.

    1984-01-01

    A finite-difference computer model was used to analyze the effect of eustatic sea-level changes on the development of the transition zone between fresh ground water and underlying saltwater in the northern Atlantic Coastal Plain. The model simulates, in cross section, the sedimentary wedge from the Delaware River estuary in New Jersey to the Continental Slope. Simulated steady-state freshwater flow is separated from static saltwater by a sharp interface. The model was used to test the sensitivity of the simulated interface position to anisotropy as well as to sea-level elevation. Increasing anisotropy causes the interface to be shallower and extend farther offshore. Lowering sea level causes the interface to be deeper and to extend farther offshore. Simulations using hydraulic conductivities based on available data suggest that the transition zone is not in equilibrium with present sea level. The position of the transition zone probably reflects a long-term average sea level of between 50 and 100 ft below present sea level. The cyclic movement of salty ground water in response to sea-level fluctuations during the Quaternary and Late Tertiary caused the saltwater to mix with freshwater, thus producing a broad transition zone. The freshwater is predominantly sodium bicarbonate in character. The saltwater, from New Jersey to Virginia, probably is a sodium calcium chloride brine. In North Carolina, it is primarily seawater.

  5. Comparison of recombinant α-hemoglobin from Crocodylus siamensis expressed in different cloning vectors and their biological properties.

    PubMed

    Maijaroen, Surachai; Anwised, Preeyanan; Klaynongsruang, Sompong; Daduang, Sakda; Boonmee, Atcha

    2016-02-01

    Hemoglobin (Hb) is an important component in red blood cells of the vertebrate. It is a major respiratory protein with oxygen or carbon dioxide transport function. Hb has been reported to contain bioactive peptides which have antibacterial and antioxidant activities. In this study, the alpha-chain hemoglobin(αHb) gene of Crocodylus siamensis was cloned into the three different expression vectors and expressed in Escherichia coli BL21 (DE3). The recombinant αHb proteins from all constructs could be expressed and purified. The result from UV-visible absorption spectra showed a similar pattern of all recombinant proteins to the oxy-hemoglobin form of intact Hb. The different recombinant αHb could exhibit antioxidant activities. All recombinant proteins could inhibit the growth of Bacillus spp. Especially, most of the recombinant proteins could inhibit the growth of Bacillus amyloliquefaciens TISTR 1045 better than intact one. The result obtained from this study can provide us further information about the possibility using of αHb as a supplementary food.

  6. Saltwater Upconing and Decay Beneath a Well Pumping Above an Interface Zone

    SciTech Connect

    Zhou, Quanlin; Bear, Jacob; Bensabat, Jacob

    2004-04-20

    Saltwater, or brine, underlies fresh water in many aquifers, with a transition zone separating them. Pumping fresh water by wells located above the transition zone produces upconing of the latter, eventually salinizing the pumped water, forcing shut-off. The salinity of the pumped water depends on the pumping rate, on the location of the well's screen, on the fresh water flow regime, and on the difference in density between fresh and salt water, expressed as a dimensionless factor called density difference factor (DDF). Following the well's shut-off, the upconed saltwater mound undergoes decay, tending to return to the pre-pumping regime. In this paper, the upconing-decay processes in an axially symmetrical system are investigated to discover how they are affected by the DDF and by the dispersivities. The code FEAS-Brine, developed for the simulation of coupled density-dependent flow and salt transport, is used. In this code, the flow equation is solved by the Galer:wqkin finite element method (FEM), while the advective-dispersive salt transport equation is solved in the Eulerian-Lagrangian framework. This code does not suffer from the instability constraint on the Peclet number in the vicinity of the pumping well, where advection dominates the salt transport. Simulation results show that upconing is very sensitive to the DDF, which, in our work, is in the range from 0 (for ideal tracer) to 0.2 (for brine). It is shown that for the DDF of 0.025 (for seawater), local upconing occurs only for low iso-salinity surfaces, while those of high salt concentration, practically, do not shift toward the pumping well. For an ideal tracer, all iso-salinity surfaces rise toward the pumping well. For brine, however, only iso-salinity surfaces of very low salinity upcone towards the pumping well. The decay process is lengthy; it takes a long time for the upconed saltwater to migrate back to the original horizontal transition zone prior to pumping. However, the wider transition

  7. Groundwater Modeling in Coastal Arid Regions Under the Influence of Marine Saltwater Intrusion

    NASA Astrophysics Data System (ADS)

    Walther, Marc; Kolditz, Olaf; Grundmann, Jens; Liedl, Rudolf

    2010-05-01

    The optimization of an aquifer's "safe yield", especially within agriculturally used regions, is one of the fundamental tasks for nowaday's groundwater management. Due to the limited water ressources in arid regions, conflict of interests arise that need to be evaluated using scenario analysis and multicriterial optimization approaches. In the context of the government-financed research project "International Water Research Alliance Saxony" (IWAS), the groundwater quality for near-coastal, agriculturally used areas is investigated under the influence of marine saltwater intrusion. Within the near-coastal areas of the study region, i.e. the Batinah plains of Northern Oman, an increasing agricultural development could be observed during the recent decades. Simultaneously, a constant lowering of the groundwater table was registered, which is primarily due to the uncontrolled and unsupervised mining of the aquifers for the local agricultural irrigation. Intensively decreased groundwater levels, however, cause an inversion of the hydraulic gradient which is naturally aligned towards the coast. This, in turn,leads to an intrusion of marine saltwater flowing inland, endangering the productivity of farms near the coast. Utilizing the modeling software package OpenGeoSys, which has been developed and constantly enhanced by the Department of Environmental Informatics at the Helmholtz Centre for Environmental Research Leipzig (UFZ; Kolditz et al., 2008), a three-dimensional, density-dependent model including groundwater flow and mass transport is currently being built up. The model, comprehending three selected coastal wadis of interest, shall be used to investigate different management scenarios. The main focus of the groundwater modelling are the optimization of well positions and pumping schemes as well as the coupling with a surface runoff model, which is also used for the determination of the groundwater recharge due to wadi runoff downstream of retention dams. Based on

  8. Predictive uncertainty analysis of a saltwater intrusion model using null-space Monte Carlo

    USGS Publications Warehouse

    Herckenrath, Daan; Langevin, Christian D.; Doherty, John

    2011-01-01

    Because of the extensive computational burden and perhaps a lack of awareness of existing methods, rigorous uncertainty analyses are rarely conducted for variable-density flow and transport models. For this reason, a recently developed null-space Monte Carlo (NSMC) method for quantifying prediction uncertainty was tested for a synthetic saltwater intrusion model patterned after the Henry problem. Saltwater intrusion caused by a reduction in fresh groundwater discharge was simulated for 1000 randomly generated hydraulic conductivity distributions, representing a mildly heterogeneous aquifer. From these 1000 simulations, the hydraulic conductivity distribution giving rise to the most extreme case of saltwater intrusion was selected and was assumed to represent the "true" system. Head and salinity values from this true model were then extracted and used as observations for subsequent model calibration. Random noise was added to the observations to approximate realistic field conditions. The NSMC method was used to calculate 1000 calibration-constrained parameter fields. If the dimensionality of the solution space was set appropriately, the estimated uncertainty range from the NSMC analysis encompassed the truth. Several variants of the method were implemented to investigate their effect on the efficiency of the NSMC method. Reducing the dimensionality of the null-space for the processing of the random parameter sets did not result in any significant gains in efficiency and compromised the ability of the NSMC method to encompass the true prediction value. The addition of intrapilot point heterogeneity to the NSMC process was also tested. According to a variogram comparison, this provided the same scale of heterogeneity that was used to generate the truth. However, incorporation of intrapilot point variability did not make a noticeable difference to the uncertainty of the prediction. With this higher level of heterogeneity, however, the computational burden of

  9. Freshwater saltwater transition zone movement during aquifer storage and recovery cycles in Brooklyn and Queens, New York City, USA

    NASA Astrophysics Data System (ADS)

    Misut, Paul E.; Voss, Clifford I.

    2007-04-01

    SummaryFreshwater storage in deep aquifers of Brooklyn and Queens, New York, USA, is under consideration as an emergency water supply for New York City. The purpose of a New York City storage and recovery system is to provide an emergency water supply during times of drought or other contingencies and would entail longer-term storage phases than a typical annual cycle. There is concern amongst neighboring coastal communities that such a system would adversely impact their local water supplies via increased saltwater intrusion. This analysis uses three-dimensional modeling of variable-density ground-water flow and salt transport to study conditions under which hypothetical aquifer storage and recovery (ASR) may not adversely impact the coastal water supplies. A range of storage, pause, and recovery phase lengths and ASR cycle repetitions were used to test scenarios that emphasize control of potential saltwater intrusion. The USGS SUTRA code was used to simulate movement of the freshwater-saltwater transition zones in a detailed model of the upper glacial, Jameco, Magothy, and Lloyd aquifers of western Long Island, New York. Simulated transition zones in the upper glacial, Jameco, and Magothy aquifers reach a steady state for 1999 stress and recharge conditions within 1 ka; however, saltwater encroachment is ongoing in the Lloyd (deepest) aquifer, for which the effects of the rise in sea level since deglaciation on transition zone equilibration are retarded by many ka due to the thick, overlying Raritan confining unit. Pumping in the 20th century has also caused widening and landward movement of the Lloyd aquifer transition zone. Simulation of scenarios of freshwater storage by injection followed by phases of pause and recovery by extraction indicates that the effect of net storage when less water is recovered than injected is to set up a hydraulic saltwater intrusion barrier in the Lloyd aquifer which may have beneficial effects to coastal water users.

  10. Freshwater-saltwater transition zone movement during aquifer storage and recovery cycles in Brooklyn and Queens, New York City, USA

    USGS Publications Warehouse

    Misut, P.E.; Voss, C.I.

    2007-01-01

    Freshwater storage in deep aquifers of Brooklyn and Queens, New York, USA, is under consideration as an emergency water supply for New York City. The purpose of a New York City storage and recovery system is to provide an emergency water supply during times of drought or other contingencies and would entail longer-term storage phases than a typical annual cycle. There is concern amongst neighboring coastal communities that such a system would adversely impact their local water supplies via increased saltwater intrusion. This analysis uses three-dimensional modeling of variable-density ground-water flow and salt transport to study conditions under which hypothetical aquifer storage and recovery (ASR) may not adversely impact the coastal water supplies. A range of storage, pause, and recovery phase lengths and ASR cycle repetitions were used to test scenarios that emphasize control of potential saltwater intrusion. The USGS SUTRA code was used to simulate movement of the freshwater-saltwater transition zones in a detailed model of the upper glacial, Jameco, Magothy, and Lloyd aquifers of western Long Island, New York. Simulated transition zones in the upper glacial, Jameco, and Magothy aquifers reach a steady state for 1999 stress and recharge conditions within 1 ka; however, saltwater encroachment is ongoing in the Lloyd (deepest) aquifer, for which the effects of the rise in sea level since deglaciation on transition zone equilibration are retarded by many ka due to the thick, overlying Raritan confining unit. Pumping in the 20th century has also caused widening and landward movement of the Lloyd aquifer transition zone. Simulation of scenarios of freshwater storage by injection followed by phases of pause and recovery by extraction indicates that the effect of net storage when less water is recovered than injected is to set up a hydraulic saltwater intrusion barrier in the Lloyd aquifer which may have beneficial effects to coastal water users. ?? 2007 Elsevier B

  11. Cationic surfactants for control of fresh- and saltwater mollusks in nuclear cooling systems

    SciTech Connect

    Post, R.M.; Mallen, E.; Lehmann, F.

    1991-11-01

    One result of the release of the US Nuclear Regulatory Commission's Generic Letter 89-13, Service Water Problems Affecting Safety-Related Equipment, was the heightened awareness of the nuclear industry to the problems of macrofouling in heat exchange systems. The principal mollusk species that contribute to freshwater macrofouling problems are Asiatic Clam (southern United States) and Zebra Mussel (Great Lakes). The predominant saltwater fouling mollusks are the Blue Mussel (Pacific, northern Atlantic), Ribbed Mussel (southern Atlantic, Gulf Coast), and American Oyster (Atlantic, Gulf Coast). The nuclear community's awareness of macrofouling problems and the ineffectiveness of intermittent chlorination programs have led to the development of several chemical control technologies for eliminating macrofouling organism infestation. One technology that has proven effective for the control of macrofouling organisms is the periodic addition of a combination of two cationic charged surfactants, specifically, alkyldimethylbenzylammonium chloride (QUAT) and dodecyl guanidine hydrochloride (DGH). Experience with the cationic surfactants at several nuclear power plants is reported.

  12. How will induced seismicity in Oklahoma respond to decreased saltwater injection rates?

    PubMed

    Langenbruch, Cornelius; Zoback, Mark D

    2016-11-01

    In response to the marked number of injection-induced earthquakes in north-central Oklahoma, regulators recently called for a 40% reduction in the volume of saltwater being injected in the seismically active areas. We present a calibrated statistical model that predicts that widely felt M ≥ 3 earthquakes in the affected areas, as well as the probability of potentially damaging larger events, should significantly decrease by the end of 2016 and approach historic levels within a few years. Aftershock sequences associated with relatively large magnitude earthquakes that occurred in the Fairview, Cherokee, and Pawnee areas in north-central Oklahoma in late 2015 and 2016 will delay the rate of seismicity decrease in those areas.

  13. How will induced seismicity in Oklahoma respond to decreased saltwater injection rates?

    PubMed Central

    Langenbruch, Cornelius; Zoback, Mark D.

    2016-01-01

    In response to the marked number of injection-induced earthquakes in north-central Oklahoma, regulators recently called for a 40% reduction in the volume of saltwater being injected in the seismically active areas. We present a calibrated statistical model that predicts that widely felt M ≥ 3 earthquakes in the affected areas, as well as the probability of potentially damaging larger events, should significantly decrease by the end of 2016 and approach historic levels within a few years. Aftershock sequences associated with relatively large magnitude earthquakes that occurred in the Fairview, Cherokee, and Pawnee areas in north-central Oklahoma in late 2015 and 2016 will delay the rate of seismicity decrease in those areas. PMID:28138533

  14. Simulation of calcite dissolution and porosity changes in saltwater mixing zones in coastal aquifers

    USGS Publications Warehouse

    Sanford, W.E.; Konikow, L.F.

    1989-01-01

    Thermodynamic models of aqueous solutions have indicated that the mixing of seawater and calcite-saturated fresh groundwater can produce a water that is undersaturated with respect to calcite. Mixing of such waters in coastal carbonate aquifers could lead to significant amounts of limestone dissolution. The potential for such dissolution in coastal saltwater mixing zones is analyzed by coupling the results from a reaction simulation model (PHREEQE) with a variable density groundwater flow and solute transport model. Idealized cross sections of coastal carbonate aquifers are simulated to estimate the potential for calcite dissolution under a variety of hydrologic and geochemical conditions. Results show that limestone dissolution in mixing zones is strongly dependent on groundwater flux and nearly independent of the dissolution kinetics of calcite. -from Authors

  15. The first field-based descriptions of pumping-induced saltwater intrusion and upconing

    NASA Astrophysics Data System (ADS)

    Houben, Georg; Post, Vincent E. A.

    2016-09-01

    Development of the ideas about the equilibrium between freshwater and saline water has received considerable attention in the literature, but little has been written so far about the earliest scientific works about well salinization. Based on a review of the literature from the second half of the 19th century and the early 20th century, this historical note explores how insights into groundwater abstraction and saltwater intrusion developed, and examples of the earliest field studies are provided. Fundamental research was driven by the need for increasing water supply, but the progress of science did not lead to sustainable management practices everywhere. Research outcomes were shared between scientists of different countries, marking the beginning of coastal hydrogeology as a scientific specialization in the first decade of the 20th century.

  16. Development of the sediment and water quality management strategies for the Salt-water River, Taiwan.

    PubMed

    Lin, C E; Chen, C T; Kao, C M; Hong, A; Wu, C Y

    2011-01-01

    The Salt-water River watershed is one of the major river watersheds in the Kaohsiung City, Taiwan. Water quality and sediment investigation results show that the river water contained high concentrations of organics and ammonia-nitrogen, and sediments contained high concentrations of heavy metals and organic contaminants. The main pollution sources were municipal and industrial wastewaters. Results from the enrichment factor (EF) and geo-accumulation index (Igeo) analyses imply that the sediments can be characterized as heavily polluted in regard to Cd, Cr, Pb, Zn, and Cu. The water quality analysis simulation program (WASP) model was applied for water quality evaluation and carrying capacity calculation. Modeling results show that the daily pollutant inputs were much higher than the calculated carrying capacity (1050 kg day(-1) for biochemical oxygen demand and 420 kg day(-1) for ammonia-nitrogen). The proposed watershed management strategies included river water dilution, intercepting sewer system construction and sediment dredging.

  17. Speciation of dissolved copper in human impacted freshwater and saltwater lakes.

    PubMed

    Wang, Deli; Gao, Yaqin; Larsson, Katarina; Lin, Wenfang

    2016-06-01

    China's natural waters are experiencing an increasingly anthropogenic perturbation widely including acidification and hypoxia, and toxic metals including copper (Cu) are subject to a series of reactions including chemical speciation and transformation. However, there is still little information available regarding such alterations of metal behaviors in China's natural waters. By using solid phase extraction technique, this study for the first time measured total dissolved Cu, and different Cu species: toxic labile Cu (referred to those free cupric ions and some weakly organic compounds adsorbed onto Chelex-100 resins), the organic refractory Cu (referred to those adsorbed onto C18 resins after passing through Chelex-100 resins), and residual Cu (obtained by subtracting labile and organic refractory fractions from the total) in a freshwater lake (the Lover) and a saltwater lagoon (the Yundang) in Xiamen, China. Our results demonstrated that both waters were characterized with relatively low levels of total dissolved Cu (5-10 nM), as a result of a net removal process dominated by particle adsorption and precipitation. Relatively high proportion of organic refractory Cu (as high as 50 %) was observed in the saltwater Yundang lagoon as a result of organic matter production and/or discharges followed by complexation nearby. On the other hand, the toxic labile Cu accounted for >40 % of the total dissolved Cu pool in these waters, and particularly the increased proportion of toxic labile Cu (as high as 70 %) occurred in the bottom sulfidic Lover Lake. Our study provides clear evidence that toxic labile Cu could be transformed under reducing environments such as deep sulfidic waters of the Lover Lake (Xiamen, China), and the releases of toxic labile metals are increasingly threatening nearby aquatic ecosystems.

  18. Predicting saltwater intrusion into aquifers in vicinity of deserts using spatio-temporal kriging.

    PubMed

    Bahrami Jovein, E; Hosseini, S M

    2017-02-01

    The primary objective of this study was to provide a detailed framework to use the spatio-temporal kriging to model the spatio-temporal variations of salinity data and predict saltwater intrusion into freshwater aquifers in the vicinity of deserts. EC data, measured in extraction wells in the Mahvelat plain located in the Northeastern part of Iran, available from 2007 to 2013, were used to demonstrate the developed framework. The source of data was not a well-designed measurement network. Therefore, to homogenize the data, spatial analysis was used to find EC distribution in the area in each year of study. To conduct the spatial analysis, a guideline and a systematic process were developed to select an appropriate kriging method and optimize its parameters. This process can be applied to different variables. After spatial analysis of EC data for all the years of the analysis period using empirical Bayesian kriging (EBK) method with manually optimized parameters, spatio-temporal and corresponding variogram analysis was conducted using R software. This process was based on a separable product-sum model applied to the data from 2007 to 2012. The data of 2013 and the data available for the years 1999 and 2006 were used for evaluating the performance of the spatio-temporal model. The EC distribution maps, developed for different years until 2021, show a high level of EC in the north, south, and west of the study area and growing saltwater intrusion into the central freshwater aquifer. This result can be attributed to the over-exploitation of the aquifer and hydraulic head and gradient distribution in the area. The framework provided in this study for spatio-temporal analysis of unstructured EC data is useful for groundwater managers in making proper decisions.

  19. Locational differences in mercury and selenium levels in 19 species of saltwater fish from New Jersey.

    PubMed

    Burger, Joanna; Jeitner, Christian; Gochfeld, Michael

    2011-01-01

    Individuals who fish, and their families that ingest self-caught fish, make decisions about where to fish, what type of fish to eat, and the quantity of fish to eat. While federal and state agencies often issue consumption advisories for some fish with high mercury (Hg) concentrations, advisories seldom provide the actual metal levels to the general public. There are few data for most saltwater fish, and even less information on variations in Hg levels in fish within a state or geographical region. The objective of this study was to provide Hg concentrations from 19 species of fish caught in different locations in New Jersey to (1) test the hypothesis that mean metal levels vary geographically, (2) provide this information to individuals who fish these coastal waters, and (3) provide a range of values for risk assessors who deal with saltwater fish exposure in the Northeastern United States. Selenium (Se) was also examined because of its purported moderating effect on the toxicity of Hg. Hg levels showed significant geographical variation for 10 of 14 species that were caught in more than one region of New Jersey, but there were significant locational differences for Se in only 5 of the fish. Mercury levels were significantly lower in fish collected from northern New Jersey (except for ling, Molva molva), compared to other regions. As might be expected, locational differences in Hg levels were greatest for fish species with the highest Hg concentrations (shark, Isurus oxyrinchus; tuna, Thunnus thynnus and T. albacares; striped bass, Morone saxatilis; bluefish, Pomatomus saltatrix). Fishers and their families might reduce their risk from Hg exposure not only by selecting fish generally lower in Hg, but by fishing predominantly in some regions over others, further lowering the potential risk. Health professionals might use these data to advise patients on which fish are safest to consume (in terms of Hg exposure) from particular geographical regions.

  20. LOCATIONAL DIFFERENCES IN MERCURY AND SELENIUM LEVELS IN 19 SPECIES OF SALTWATER FISH FROM NEW JERSEY

    PubMed Central

    Burger, Joanna; Jeitner, Christian; Gochfeld, Michael

    2014-01-01

    Individuals who fish, and their families that ingest self-caught fish, make decisions about where to fish, what type of fish to eat, and the quantity of fish to eat. While federal and state agencies often issue consumption advisories for some fish with high mercury (Hg) concentrations, advisories seldom provide the actual metal levels to the general public. There are few data for most saltwater fish, and even less information on variations in Hg levels in fish within a state or geographical region. The objective of this study was to provide Hg concentrations from 19 species of fish caught in different locations in New Jersey to (1) test the hypothesis that mean metal levels vary geographically, (2) provide this information to individuals who fish these coastal waters, and (3) provide a range of values for risk assessors who deal with saltwater fish exposure in the Northeastern United States. Selenium (Se) was also examined because of its purported moderating effect on the toxicity of Hg. Hg levels showed significant geographical variation for 10 of 14 species that were caught in more than one region of New Jersey, but there were significant locational differences for Se in only 5 of the fish. Mercury levels were significantly lower in fish collected from northern New Jersey (except for ling, Molva molva), compared to other regions. As might be expected, locational differences in Hg levels were greatest for fish species with the highest Hg concentrations (shark, Isurus oxyrinchus; tuna, Thunnus thynnus and T. albacares; striped bass, Morone saxatilis; bluefish, Pomatomus saltatrix). Fishers and their families might reduce their risk from Hg exposure not only by selecting fish generally lower in Hg, but by fishing predominantly in some regions over others, further lowering the potential risk. Health professionals might use these data to advise patients on which fish are safest to consume (in terms of Hg exposure) from particular geographical regions. PMID:21598171

  1. The Drosophila fork head domain protein crocodile is required for the establishment of head structures.

    PubMed Central

    Häcker, U; Kaufmann, E; Hartmann, C; Jürgens, G; Knöchel, W; Jäckle, H

    1995-01-01

    The fork head (fkh) domain defines the DNA-binding region of a family of transcription factors which has been implicated in regulating cell fate decisions across species lines. We have cloned and molecularly characterized the crocodile (croc) gene which encodes a new family member from Drosophila. croc is expressed in the head anlagen of the blastoderm embryo under the control of the anterior, the dorsoventral and the terminal maternal organizer systems. The croc mutant phenotype indicates that the croc wild-type gene is required to function as an early patterning gene in the anterior-most blastoderm head segment anlage and for the establishment of a specific head skeletal structure that derives from the non-adjacent intercalary segment at a later stage of embryogenesis. As an early patterning gene, croc exerts unusual properties which do not allow it to be grouped among the established segmentation genes. A single-site mutation within the croc fkh domain, which causes a replacement of the first out of four conserved amino acid residues thought to be involved in the coordinate binding of Mg2+, abolishes the DNA binding of the protein in vitro. In view of the resulting lack-of-function mutant phenotype, it appears likely that metal binding by the affected region of the fkh domain is crucial for proper folding of the DNA-binding structure. Images PMID:7489720

  2. Allosaurus, crocodiles, and birds: evolutionary clues from spiral computed tomography of an endocast.

    PubMed

    Rogers, S W

    1999-10-15

    Because the brain does not usually leave direct evidence of its existence in the fossil record, our view of this structure in extinct species has relied upon inferences drawn from comparisons between parts of the skeleton that do fossilize or with modern-day relatives that survived extinction. However, soft-tissue structure preservation may indeed occasionally occur, particularly in the endocranial space. By applying modern imaging and analysis methods to such natural cranial "endocasts," we can now learn more than ever thought possible about the brains of extinct species. I will discuss one such example in which spiral computed tomography (CT) scanning analysis has been successfully applied to reveal preserved internal structures of a naturally occurring endocranial cast of Allosaurus fragilis, the dominant carnivorous dinosaur of the late Jurassic period. The ability to directly examine the neuroanatomy of an extinct dinosaur, whose modern-day relatives are birds and crocodiles, has exciting implications about Allosaurus' behavior, its adaptive responses to its environment, and its eventual extinction.

  3. Imaging the Stratification and Tidal Dynamics of a Saltwater-Freshwater Interface Using Continuous Shallow Electrical Resistivity Techniques in the Karst Coastal Biscayne Aquifer, South Florida.

    NASA Astrophysics Data System (ADS)

    Stalker, J. C.; Whitman, D.; Price, R. M.

    2008-05-01

    Shallow ground resistivity was used to image the saline-freshwater mixing zone in the subsurface due to saltwater intrusion at a site less than 2 kilometers from the coastline of Biscayne Bay, an estuary in South Florida. Resistivity arrays have several advantages when applied to coastal groundwater environments. Experiments can be set up to measure several depths by varying the electrode spacing. Additionally Resistivity techniques can be used to resolve multiple changes in lithology and compositions making them ideal for saltwater intrusion studies. Miami-Dade county and adjoining the Biscayne Bay are underlain by the karst Biscayne aquifer system where the freshwater aquifer is in direct contact with the saline bay system. Saltwater intrusion has been a continuous problem since anthropogenic alteration of the hydrological system occurred to manage flood control and promote agriculture. To better understand the nature and dynamics of the saltwater intrusion in the near coastal shallow subsurface, a Supersting 28-electrode resistivity unit, configured in a Wenner array, was used to produce a 2D image of the freshwater/brackish water/saltwater stratification, and was deployed in a continuous data collection mode to observe the movement of the saltwater mixing zone through a tidal cycle. Results show at a depth of 9m below the surface there is a 2m meter thick freshwater layer above the brackish/saltwater mixing zone. In addition, the continuous imaging of the mixing zone over a tidal cycle shows a fluctuation landward and seaward of the mixing zone as the tide floods and ebbs. This technique provides an efficient tool for detection and characterization of the saltwater/freshwater mixing zone in shallow coastal aquifers and lends new insight to the stratification and thicknesses of the fresh and saline layers. In addition the detection of cyclical tidal movement and an estimate of its magnitude will aid in the understanding of the mixing zone geochemistry and

  4. Evaluation of the effects of sea-level change and coastal canal management on saltwater intrusion in the Biscayne aquifer of south Florida, USA

    NASA Astrophysics Data System (ADS)

    Hughes, J. D.; Sifuentes, D. F.; White, J.

    2015-12-01

    Sea-level increases are expected to have an effect on the position of the freshwater-saltwater interface in the Biscayne aquifer in south Florida as a result of the low topographic relief of the area and high rates of groundwater withdrawal from the aquifer. To study the effects that future sea-level increases will have on saltwater intrusion in the Biscayne aquifer in Broward County, Florida, a three-dimensional, variable-density, groundwater-flow and transport model was developed. The model was calibrated to observed groundwater heads and chloride concentrations for a 62-year period that includes historic increases in sea level, development of a surface-water management system to control flooding, and increases in groundwater withdrawals as the area transitioned from agricultural to urban land uses. Sensitivity analyses indicate that downward leakage of saltwater from coastal canals and creeks was the primary source of saltwater to the Biscayne aquifer during the last 62-years in areas where the surface-water system is not actively managed and is tidally influenced. In areas removed from the coastal canals and creeks or under active surface-water management, historic groundwater withdrawals were the primary cause of saltwater intrusion into the aquifer. Simulation of future conditions suggests that possible increases in sea level will result in additional saltwater intrusion. Model scenarios suggest that additional saltwater intrusion will be greatest in areas where coastal canals and creeks were historically the primary source of seawater. Future saltwater intrusion in those areas, however, may be reduced by relocation of salinity-control structures.

  5. Changes in the saltwater interface corresponding to the installation of a seepage barrier near Lake Okeechobee, Florida

    USGS Publications Warehouse

    Prinos, Scott T.; Valderrama, Robert

    2015-01-01

    At five of the monitoring-well cluster locations, a long-screened well was also installed for monitoring and comparison purposes. These long-screened wells are 160 to 200 ft deep, and have open intervals ranging from 145 to 185 ft in length. Water samples were collected at depth intervals of about 5 to 10 ft, using 3-ft-long straddle packers to isolate each sampling interval. The results of monitoring conducted using these long-screened interval wells were generally too variable to identify any changes that might be associated with the seepage barrier. Samples from one of these long-screened interval wells failed to detect the saltwater interface evident in samples and TSEMIL datasets from a collocated well cluster. This failure may have been caused by downward flow of freshwater from above the saltwater interface in the well bore.

  6. Monitoring and Assessment of Saltwater Intrusion using Geographic Information Systems (GIS), Remote Sensing and Geophysical measurements of Guimaras Island, Philippines

    NASA Astrophysics Data System (ADS)

    Hernandez, B. C. B.

    2015-12-01

    Degrading groundwater quality due to saltwater intrusion is one of the key challenges affecting many island aquifers. These islands hold limited capacity for groundwater storage and highly dependent on recharge due to precipitation. But its ease of use, natural storage and accessibility make it more vulnerable to exploitation and more susceptible to encroachment from its surrounding oceanic waters. Estimating the extent of saltwater intrusion and the state of groundwater resources are important in predicting and managing water supply options for the community. In Guimaras island, central Philippines, increasing settlements, agriculture and tourism are causing stresses on its groundwater resource. Indications of saltwater intrusion have already been found at various coastal areas in the island. A Geographic Information Systems (GIS)-based approach using the GALDIT index was carried out. This includes six parameters assessing the seawater intrusion vulnerability of each hydrogeologic setting: Groundwater occurrence, Aquifer hydraulic conductivity, Groundwater Level above sea, Distance to shore, Impact of existing intrusion and Thickness of Aquifer. To further determine the extent of intrusion, Landsat images of various thematic layers were stacked and processed for unsupervised classification and electrical resistivity tomography using a 28-electrode system with array lengths of 150 and 300 meters was conducted. The GIS index showed where the vulnerable areas are located, while the geophysical measurements and images revealed extent of seawater encroachment along the monitoring wells. These results are further confirmed by the measurements collected from the monitoring wells. This study presents baseline information on the state of groundwater resources and increase understanding of saltwater intrusion dynamics in island ecosystems by providing a guideline for better water resource management in the Philippines.

  7. Saltwater movement in the upper Floridan aquifer beneath Port Royal Sound, South Carolina

    USGS Publications Warehouse

    Smith, Barry S.

    1994-01-01

    Freshwater for Hilton Head Island, South Carolina, is supplied by withdrawals from the Upper Floridan aquifer. Freshwater for the nearby city of Savannah, Georgia, and for the industry that has grown adjacent to the city, has also been supplied, in part, by withdrawal from the Upper Floridan aquifer since 1885. The withdrawal of ground water has caused water levels in the Upper Floridan aquifer to decline over a broad area, forming a cone of depression in the potentiometric surface of the aquifer centered near Savannah. In 1984, the cone of depression extended beneath Hilton Head Island as far as Port Royal Sound. Flow in the aquifer, which had previously been toward Port Royal Sound, has been reversed, and, as a result, saltwater in the aquifer beneath Port Royal Sound has begun to move toward Hilton Head Island. The Saturated-Unsaturated Transport (SUTRA) model of the U.S. Geological Survey was used for the simulation of density-dependent ground-water flow and solute transport for a vertical section of the Upper Floridan aquifer and upper confining unit beneath Hilton Head Island and Port Royal Sound. The model simulated a dynamic equilibrium between the flow of seawater and freshwater in the aquifer near the Gyben-Herzberg position estimated for the period before withdrawals began in 1885; it simulated reasonable movements of brackish water and saltwater from that position to the position determined by chemical analyses of samples withdrawn from the aquifer in 1984, and it approximated hydraulic heads measured in the aquifer in 1976 and 1984. The solute-transport simulations indicate that the transition zone would continue to move toward Hilton Head Island even if pumping ceased on the island. Increases in existing withdrawals or additional withdrawals on or near Hilton Head Island would accelerate movement of the transition zone toward the island, but reduction in withdrawals or the injection of freshwater would slow movement toward the island, according to the

  8. Saltwater intrusion in the Floridan aquifer system near downtown Brunswick, Georgia, 1957–2015

    USGS Publications Warehouse

    Cherry, Gregory S.; Peck, Michael

    2017-02-16

    IntroductionThe Floridan aquifer system (FAS) consists of the Upper Floridan aquifer (UFA), an intervening confining unit of highly variable properties, and the Lower Floridan aquifer (LFA). The UFA and LFA are primarily composed of Paleocene- to Oligocene-age carbonate rocks that include, locally, Upper Cretaceous rocks. The FAS extends from coastal areas in southeastern South Carolina and continues southward and westward across the coastal plain of Georgia and Alabama, and underlies all of Florida. The thickness of the FAS varies from less than 100 feet (ft) in aquifer outcrop areas of South Carolina to about 1,700 ft near the city of Brunswick, Georgia.Locally, in southeastern Georgia and the Brunswick– Glynn County area, the UFA consists of an upper water-bearing zone (UWBZ) and a lower water-bearing zone (LWBZ), as identified by Wait and Gregg (1973), with aquifer test data indicating the upper zone has higher productivity than the lower zone. Near the city of Brunswick, the LFA is composed of two permeable zones: an early middle Eocene-age upper permeable zone (UPZ) and a highly permeable lower zone of limestone (LPZ) of Paleocene and Late Cretaceous age that includes a deeply buried, cavernous, saline water-bearing unit known as the Fernandina permeable zone. Maslia and Prowell (1990) inferred the presence of major northeast–southwest trending faults through the downtown Brunswick area based on structural analysis of geophysical data, northeastward elongation of the potentiometric surface of the UFA, and breaches in the local confining unit that influence the area of chloride contamination. Pronounced horizontal and vertical hydraulic head gradients, caused by pumping in the UFA, allow saline water from the FPZ to migrate upward into the UFA through this system of faults and conduits.Saltwater was first detected in the FAS in wells completed in the UFA near the southern part of the city of Brunswick in late 1957. By the 1970s, a plume of groundwater

  9. Effects of climate variability on saltwater intrusions in coastal aquifers in Southern Denmark

    NASA Astrophysics Data System (ADS)

    Meyer, Rena; Sonnenborg, Torben; Engesgaard, Peter; Høyer, Anne-Sophie; Jørgensen, Flemming; Hisnby, Klaus; Hansen, Birgitte; Jensen, Jørn Bo; Piotrowski, Jan A.

    2016-04-01

    As in many other regions of the world fresh water supply in Denmark is based on groundwater resources. Aquifers in the low-lying areas in the south-west of Jutland are particularly vulnerable to saltwater intrusions which are likely to intensify due to relative sea level rise. To understand the dynamics and development of this complex flow system, the initial hydrodynamic conditions imposed by the last Scandinavian Ice Sheet (SIS) must be taken into account. The whole region has undergone changes in climatic and hydraulic conditions within the last 15000 years that may show influence on the present flow conditions. It is likely that the groundwater-flow dynamics, driven by the postglacial hydraulic head drop and the relative sea level rise are not yet equilibrated. Enhanced by the potential future sea level rise due to climate change, contamination of fresh-water aquifers will continue. The 2800-km2 - large coast-to-coast study area located in the southern part of Jutland was partly overridden by the Weichselian ice sheet. Geophysical and geological mapping shows salt water intrusions up to 20 km inland from the present coast. Based on a geological voxel model spanning Miocene through Quaternary deposits a large-scale 3D numerical groundwater flow and salt water transport model has been developed. It includes density-driven flow and simulates the distribution of the current saltwater intrusions and their evolution during the last 15000 years. Particle tracking and direct age simulations are performed to identify recharge areas and constrain groundwater ages. The simulated ages are compared to ages derived from isotope analysis of groundwater samples both from Miocene and Quaternary aquifers. The origin of the groundwater is determined based on isotopic and chemical composition. Additionally, heavy noble gas analysis is carried out to estimate recharge temperatures and mechanisms at locations where groundwater recharge during the last glaciation is indicated. This

  10. Alligators and Crocodiles Have High Paracellular Absorption of Nutrients, But Differ in Digestive Morphology and Physiology.

    PubMed

    Tracy, Christopher R; McWhorter, Todd J; Gienger, C M; Starck, J Matthias; Medley, Peter; Manolis, S Charlie; Webb, Grahame J W; Christian, Keith A

    2015-12-01

    Much of what is known about crocodilian nutrition and growth has come from animals propagated in captivity, but captive animals from the families Crocodilidae and Alligatoridae respond differently to similar diets. Since there are few comparative studies of crocodilian digestive physiology to help explain these differences, we investigated young Alligator mississippiensis and Crocodylus porosus in terms of (1) gross and microscopic morphology of the intestine, (2) activity of the membrane-bound digestive enzymes aminopeptidase-N, maltase, and sucrase, and (3) nutrient absorption by carrier-mediated and paracellular pathways. We also measured gut morphology of animals over a larger range of body sizes. The two species showed different allometry of length and mass of the gut, with A. mississippiensis having a steeper increase in intestinal mass with body size, and C. porosus having a steeper increase in intestinal length with body size. Both species showed similar patterns of magnification of the intestinal surface area, with decreasing magnification from the proximal to distal ends of the intestine. Although A. mississippiensis had significantly greater surface-area magnification overall, a compensating significant difference in gut length between species meant that total surface area of the intestine was not significantly different from that of C. porosus. The species differed in enzyme activities, with A. mississippiensis having significantly greater ability to digest carbohydrates relative to protein than did C. porosus. These differences in enzyme activity may help explain the differences in performance between the crocodilian families when on artificial diets. Both A. mississippiensis and C. porosus showed high absorption of 3-O methyl d-glucose (absorbed via both carrier-mediated and paracellular transport), as expected. Both species also showed surprisingly high levels of l-glucose-uptake (absorbed paracellularly), with fractional absorptions as high as those

  11. Crocodile blood extract induces the apoptosis of lung cancer cells through PTEN activity.

    PubMed

    Ou, Yuqian; Ho, Wing Shing

    2016-09-01

    Current treatment strategies for lung cancer cause undesirable side‑effects. Integrated medicine with a curative approach has become a common approach to the treatment strategy. Recent studies suggest that American alligator blood is effective in reducing colorectal cancer cell viability in vitro, but the mechanism remains unclear. In the present study, we aimed to study the anticancer activity of crocodile blood extracts on lung cancer cell line A549 and investigate the possible mechanisms involved. In vitro studies were utilized to investigate the effects on the cancer cells after incubation with the blood extracts. The active fraction that showed more efficacy in inhibiting cell growth was characterized in the supernatant (S2) from whole blood extracts. High performance liquid chromatography (HPLC) analysis revealed that S2 contained more polar moiety from whole blood. S2 induced DNA fragmentation. Cell cycle arrest in the G1/M phase was demonstrated and mitochondrial membrane permeability was disrupted. An increase in the generation of reactive oxygen species (ROS) and increased activities of caspase-3 and caspase-7 were detected. Furthermore, release of cytochrome c, upregulation of expression of Bax, p53, p21, Bid, cleaved forms of the caspase family and PARP along with downregulation of Bcl-2, PCNA, MDM2, caspase‑8, wild types of caspase family proteins and PARP were recorded after treatment with S2 fractions. Moreover, the PI3K/AKT survival pathway was downregulated by S2 fractions in the lung cancer cell line.

  12. Why the Long Face? The Mechanics of Mandibular Symphysis Proportions in Crocodiles

    PubMed Central

    Walmsley, Christopher W.; Smits, Peter D.; Quayle, Michelle R.; McCurry, Matthew R.; Richards, Heather S.; Oldfield, Christopher C.; Wroe, Stephen; Clausen, Phillip D.; McHenry, Colin R.

    2013-01-01

    Background Crocodilians exhibit a spectrum of rostral shape from long snouted (longirostrine), through to short snouted (brevirostrine) morphologies. The proportional length of the mandibular symphysis correlates consistently with rostral shape, forming as much as 50% of the mandible’s length in longirostrine forms, but 10% in brevirostrine crocodilians. Here we analyse the structural consequences of an elongate mandibular symphysis in relation to feeding behaviours. Methods/Principal Findings Simple beam and high resolution Finite Element (FE) models of seven species of crocodile were analysed under loads simulating biting, shaking and twisting. Using beam theory, we statistically compared multiple hypotheses of which morphological variables should control the biomechanical response. Brevi- and mesorostrine morphologies were found to consistently outperform longirostrine types when subject to equivalent biting, shaking and twisting loads. The best predictors of performance for biting and twisting loads in FE models were overall length and symphyseal length respectively; for shaking loads symphyseal length and a multivariate measurement of shape (PC1– which is strongly but not exclusively correlated with symphyseal length) were equally good predictors. Linear measurements were better predictors than multivariate measurements of shape in biting and twisting loads. For both biting and shaking loads but not for twisting, simple beam models agree with best performance predictors in FE models. Conclusions/Significance Combining beam and FE modelling allows a priori hypotheses about the importance of morphological traits on biomechanics to be statistically tested. Short mandibular symphyses perform well under loads used for feeding upon large prey, but elongate symphyses incur high strains under equivalent loads, underlining the structural constraints to prey size in the longirostrine morphotype. The biomechanics of the crocodilian mandible are largely consistent

  13. Molecular genetic variation and structure of Southeast Asian crocodile (Tomistoma schlegelii): Comparative potentials of SSRs versus ISSRs.

    PubMed

    Shafiei-Astani, Behnam; Ong, Alan Han Kiat; Valdiani, Alireza; Tan, Soon Guan; Yien, Christina Yong Seok; Ahmady, Fatemeh; Alitheen, Noorjahan Banu; Ng, Wei Lun; Kuar, Taranjeet

    2015-10-15

    Tomistoma schlegelii, also referred to as the "false gharial", is one of the most exclusive and least known of the world's fresh water crocodilians, limited to Southeast Asia. Indeed, lack of economic value for its skin has led to neglect the biodiversity of the species. The current study aimed to investigate the mentioned case using 40 simple sequence repeat (SSR) primer pairs and 45 inter-simple sequence repeat (ISSR) primers. DNA analysis of 17 T. schlegelii samples using the SSR and ISSR markers resulted in producing a total of 49 and 108 polymorphic bands, respectively. Furthermore, the SSR- and ISSR-based cluster analyses both generated two main clusters. However, the SSR based results were found to be more in line with the geographical distributions of the crocodile samples collected across the country as compared with the ISSR-based results. The observed heterozygosity (HO) and expected heterozygosity (HE) of the polymorphic SSRs ranged between 0.588-1 and 0.470-0.891, respectively. The present results suggest that the Malaysian T. schlegelii populations had originated from a core population of crocodiles. In cooperation with the SSR markers, the ISSRs showed high potential for studying the genetic variation of T. schlegelii, and these markers are suitable to be employed in conservation genetic programs of this endangered species. Both SSR- and ISSR-based STRUCTURE analyses suggested that all the individuals of T. schlegelii are genetically similar with each other.

  14. A Tectonic Model for Paleoproterozoic Crocodile Structures at Karelian Svecofennian Boundary - Results from FIRE-1 and BABEL2&3

    NASA Astrophysics Data System (ADS)

    Korja, A.; Lahtinen, R.; Heikkinen, P.; Kukkonen, I. T.; Fire Working Group

    2003-04-01

    The Karelian - Svecofennian boundary zone has long been recognized as an important suture zone. Three competing models have been proposed for this boundary: continent-arc/continent collision zone, back-arc/retro-arc basin related to NE-directed subduction occurring further SW and strike-slip model, when all the Svecofennian parts are considered exotic. The geometry and style of deformation at depth has not been known and thus, the models have been rather schematic. The new reflection data along FIRE1-profile (2001) and older reflection data (BABEL 2&3) suggest a crocodile structure composed of Karelian passive margin wedge that has caused the splitting of Svecofennian island arc material into crocodile jaws. The reflection and refraction data together with lithological and structural evidence indicate that westward subduction consumed the ocean floor between the continent and the arc. In the onset of the collision, the remnants of the ocean floor (ophiolites) together with sedimentary material were obducted on the advancing continental margin. During continued convergence the young and hot island arc part split after which it was both under and overthrust on the continent. The collision was locked when the thickened continental margin was amalgamated with hard core of the continental island arc.

  15. A direct biocombinatorial strategy toward next generation, mussel-glue inspired saltwater adhesives.

    PubMed

    Wilke, Patrick; Helfricht, Nicolas; Mark, Andreas; Papastavrou, Georg; Faivre, Damien; Börner, Hans G

    2014-09-10

    Biological materials exhibit remarkable, purpose-adapted properties that provide a source of inspiration for designing new materials to meet the requirements of future applications. For instance, marine mussels are able to attach to a broad spectrum of hard surfaces under hostile conditions. Controlling wet-adhesion of synthetic macromolecules by analogue processes promises to strongly impact materials sciences by offering advanced coatings, adhesives, and glues. The de novo design of macromolecules to mimic complex aspects of mussel adhesion still constitutes a challenge. Phage display allows material scientists to design specifically interacting molecules with tailored affinity to material surfaces. Here, we report on the integration of enzymatic processing steps into phage display biopanning to expand the biocombinatorial procedure and enable the direct selection of enzymatically activable peptide adhesion domains. Adsorption isotherms and single molecule force spectroscopy show that those de novo peptides mimic complex aspects of bioadhesion, such as enzymatic activation (by tyrosinase), the switchability from weak to strong binders, and adsorption under hostile saltwater conditions. Furthermore, peptide-poly(ethylene oxide) conjugates are synthesized to generate protective coatings, which possess anti-fouling properties and suppress irreversible interactions with blood-plasma protein cocktails. The extended phage display procedure provides a generic way to non-natural peptide adhesion domains, which not only mimic nature but also improve biological sequence sections extractable from mussel-glue proteins. The de novo peptides manage to combine several tasks in a minimal 12-mer sequence and thus pave the way to overcome major challenges of technical wet glues.

  16. Forensic application of intrarenal aquaporin-2 expression for differential diagnosis between freshwater and saltwater drowning.

    PubMed

    An, Jun-Ling; Ishida, Yuko; Kimura, Akihiko; Kondo, Toshikazu

    2010-03-01

    Aquaporins (AQPs) are a family of homologous water channel proteins. In this study, the expressions of AQP1, 2, and 4 were immunohistochemically examined in kidney samples to evaluate their forensic applicability to differentiate between freshwater drowning (FWD) and saltwater drowning (SWD). Kidney samples were obtained from 51 drowning cases (23 FWD and 28 SWD) and 19 non-drowning cases. AQP1 was expressed in the proximal tubules and glomeruli, and AQP4 was localized in the collecting ducts. However, there were no significant differences in AQP1 and AQP4 expressions among FWD, SWD, and control groups. Immunohistochemically, AQP2 was predominantly expressed in the apical plasma membrane of the collecting duct principal cells in all kidney samples of FWD and SWD. Morphometrically, AQP2 expression at the apical plasma membrane of collecting ducts was significantly enhanced in SWD group, compared with FWD and control groups. On the other hand, AQP-2 expression was significantly lower in FWD group than in control group. Moreover, in drowning cases, there was no correlation between post-submersion intervals and AQP expression. From a forensic aspect, immunohistochemical detection of AQP2 in the kidney can be considered a valuable marker to differentiate between FWD and SWD.

  17. Differential diagnosis between freshwater drowning and saltwater drowning based on intrapulmonary aquaporin-5 expression.

    PubMed

    Hayashi, Takahito; Ishida, Yuko; Mizunuma, Shinya; Kimura, Akihiko; Kondo, Toshikazu

    2009-01-01

    The intrapulmonary expression of aquaporin-5 (AQP5) was examined in an experimental drowning model and forensic autopsy cases to discuss the possibility for differentiation between freshwater drowning (FWD) and saltwater drowning (SWD). In animal experiments, mice were classified into four groups: (group I: FWD; group II: SWD; group III: postmortem immersion (PI); and group IV: cervical dislocation as controls. In group I, intrapulmonary AQP5 expression was significantly suppressed at both gene and protein levels, compared with the other three groups, and there was no significant difference in AQP5 expression among groups II to IV. In the next series, we examined AQP5 gene expression in human lung samples obtained from forensic autopsies at less than 48 h postmortem (nine FWD cases, five SWD cases, and 14 other cases). Although AQP5 mRNA could be detected in all lung samples under the employed experimental conditions, the intrapulmonary gene expression of AQP5 in FWD was significantly attenuated compared with the other groups. These observations imply that AQP5 expression in type I alveolar epithelial cells was suppressed by hypotonic water to prevent hemodilution from the physiological aspect. Moreover, the analysis of intrapulmonary AQP5 expression would be forensically useful for differentiation between FWD and SWD, or between FWD and PI.

  18. Halotolerant Ability and α-Amylase Activity of Some Saltwater Fungal Isolates

    PubMed Central

    Niknejad, Farhad; Moshfegh, Mahsa; Najafzadeh, Mohammad Javad; Houbraken, Jos; Rezaei, Shahla; Zarrini, Gholamreza; Faramarzi, Mohammad Ali; Nafissi-Varcheh, Nastaran

    2013-01-01

    Four halotolerant fungal isolates originating from the saltwater Lake Urmia in Iran were selected during a screening program for salt resistance and α-amylase activity. The isolates were identified based on sequencing the ITS region and a part of the β-tubulin gene, as Penicillium chrysogenum (isolate U1; CBS 132820), Fusarium incarnatum (isolate U2; CBS 132821), and Penicillium polonicum (isolate U3; CBS 132822, and isolate U4; CBS 132823). The growth of these isolates was determined by measuring the colony diameter and mycelia dry weight in Sabouraud dextrose agar and yeast nitrogen base medium supplemented with NaCl, KCl, and LiCl. Isolate U4 showed a growth up in 15% NaCl and U1 was the only isolate that could grow in 20% KCl. None of the strains grew in a media containing LiCl. The salt supplemented medium did not increase the size of colony diameter in all isolates (p > 0.05). The ability of the selected isolates for amylase production was quantitatively tested and showed that P. polonicum isolate U4 was the most potent producer of amylase with a yield of 260.9 U/L after 60 h, whereas P. polonicum isolate U3 was the lowest one with a production level of 97.9 U/L after 48 h. P. polonicum isolate U4 could be a suitable candidate for production of amylase on an industrial scale after optimization. PMID:24250679

  19. Radial Dupuit interface flow to assess the aquifer storage and recovery potential of saltwater aquifers

    NASA Astrophysics Data System (ADS)

    Bakker, Mark

    2010-02-01

    A new accurate numerical solution is presented for aquifer storage and recovery (ASR) systems in coastal aquifers; flow is approximated as radial Dupuit interface flow. The radial velocities of points on the interface are a function of time, the vertical coordinate, and the dimensionless parameter D (the discharge of the well divided by the product of the hydraulic conductivity, the square of the aquifer thickness, and the dimensionless density difference). The recovery efficiency of an ASR system (the ratio of the recovered volume of water divided by the injected volume of water) is determined by D and by the relative lengths of the injection, storage and recovery periods. Graphs are produced for the recovery efficiency as a function of parameter D for ASR operations with and without storage periods and for multiple cycles. The presented solutions and graphs are to be used as screening tools to assess the feasibility of specific injection, storage and recovery scenarios of planned ASR systems in saltwater aquifers without having to run complicated flow and transport models. When the screening tool indicates that recovery efficiencies are acceptable, the consideration of other features such as mixing and chemistry is warranted.

  20. Impact of saltwater spray andsand deposition on the coastal annualTriplasis purpurea (Poaceae).

    PubMed

    Cheplick, G P; Demetri, H

    1999-05-01

    Pioneer coastal plants occur in areas where sand movement and airborne salt are common. The objectives of this study were to (1) quantify natural levels of salt and sand deposition in relation to distance from the shoreline of Staten Island, New York, and (2) experimentally determine the impact of saltwater sprays and partial sand burial on growth and reproduction of the native dunegrass Triplasis purpurea. This summer annual matures most seeds in cleistogamous spikelets on leaf sheath-enclosed axillary panicles along culm internodes. Levels of salt deposition onto T. purpurea shoots over 6 d were determined with a conductivity meter to be 175 μg/cm(2) at 39 m from shore in 1997, but declined rapidly with increasing distances to 90 m. Sand deposition over 1 mo in the summer averaged 30 mm at 72-90 m from shore. In a greenhouse factorial experiment, seedlings were unburied, buried to 50% height, or buried to 75% height and simultaneously subjected to no sprays, two sprays/wk, or six sprays/wk of seawater over the summer. Sand deposition increased plant size and seed production, but seawater sprays were mostly detrimental, reducing plant size, seed production, and seed mass. However, T. purpurea tolerated moderate levels of salt deposition. The stimulation of growth and reproduction in partially buried plants is adaptive on the sandy soils. Prolific seed production and tolerance to moderate levels of airborne salt allow this annual to maintain high population densities close to shore.

  1. The impact of encroachment of mangroves into saltmarshes on saltwater mosquito habitats.

    PubMed

    Dale, Pat; Eslami-Andargoli, Leila; Knight, Jon

    2013-12-01

    Will mangrove encroachment into saltmarshes affect saltwater mosquito habitats? To address this, we synthesized information from two perspectives: 1) at a detailed level, the immature mosquito habitat within mangroves; 2) at a more general or regional level, changes due to mangrove expansion into saltmarshes. This is a synthesis of two research projects. One showed that mosquito larval habitats in mangroves are complex, related to the detailed interactions between topography and tidal patterns and that not all parts of a mangrove forest are suitable habitat. The other, based on remote sensing and analysis of rainfall data, showed that mangrove encroachment in eastern Australia is related to both climate and human land use over several decades (1972-2004). An important question emerged: when mangroves encroach into saltmarshes will they displace saltmarsh immature mosquito habitats or will they replace them with mangrove ones? There is no simple answer: it will vary with climate change and sea level scenario and how these affect the system. We conclude that mosquito management, which is locally implemented, needs to be integrated with land use planning systems, which often operate at a more general level.

  2. Reclamation of saltwater-contaminated soil in the Big Lake Field

    SciTech Connect

    Weathers, M.L.; Moore, K.R.; Ford, D.L.

    1994-09-01

    Since the discovery of the 1 Santa Rita well in 1923, millions of barrels of saltwater have been produced along with 135 million bbl of oil from the Big Lake field in Reagan County, Texas. Until the early 1960s, the accepted disposal method for the produced water was surface discharge to large evaporation ponds north of the field. Produced water was allowed to flow from wells to the ponds via natural topographic drainage. This practice resulted in 7000 ac of eroded, barren landscape characterized by highly saline soils incapable of supporting vegetation. In 1989, the University of Texas System, the U.S.D.A. Soil Conservation Service, and Marathon Oil Company, which acquired Big Lake field in 1962, initiated an experimental project to reclaim the affected land and restore it to rangeland productivity. An underground drainage system, consisting of 125,000 ft of buried drainage conduit and eight collection sumps, was installed over nearly 300 ac of the affected area. Earthen terraces were constructed to capture and hold rainwater to aid downward percolation and leaching of salts from the soil profile. Salts leached from the soil are captured by the drainage system and pumped to injection wells for disposal. The excellent revegetation that has occurred over the test area after three years of operations is encouraging and has shown the need for expanding and enhancing the existing system with supplemental water from freshwater wells, application of soil-amending agents, additional terracing, and selective planting of salt-tolerant species.

  3. Hydrogeology and extent of saltwater intrusion of the Great Neck peninsula, Great Neck, Long Island, New York

    USGS Publications Warehouse

    Stumm, Frederick

    2001-01-01

    Great Neck, a peninsula, in the northwestern part of Nassau County, N.Y., is underlain by unconsolidated deposits that form a sequence of aquifers and confining units. Seven public-supply wells have been affected by the intrusion of saltwater from the surrounding embayments (Little Neck Bay, Long Island Sound, Manhasset Bay). Fifteen observation wells were drilled in 1991–96 for the collection of hydrogeologic, geochemical, and geophysical data to delineate the subsurface geology and extent of saltwater intrusion within the peninsula. Continuous high-resolution seismic-reflection surveys in the embayments surrounding the Great Neck peninsula and the Manhasset Neck peninsula to the east were completed in 1993 and 1994.Two hydrogeologic units are newly proposed herein.the North Shore aquifer and the North Shore confining unit. The new drill-core data collected in 1991–96 indicate that the Lloyd aquifer, the Raritan confining unit, and the Magothy aquifer have been completely removed from the northern part of the peninsula by extensive glacial erosion.Water levels at selected observation wells were measured quarterly throughout the study. The results from two studies of the effects of tides on ground-water levels in 1992 and 1993 indicate that water levels at wells screened within the North Shore and Lloyd aquifers respond to tides and pumping effects, but those in the overlying upper glacial aquifer (where the water table is located) do not. Data from quarterly water-level measurements and the tidal-effect studies indicate the North Shore and Lloyd aquifers to be hydraulically connected.Offshore seismic-reflection surveys in the surrounding embayments indicate at least two glacially eroded buried valleys with subhorizontal, parallel reflectors indicative of draped bedding that is interpreted as infilling by silt and clay. The buried valleys (1) truncate the surrounding coarse-grained deposits, (2) are asymmetrical and steep sided, (3) trend northwest

  4. Simulation of ground-water flow and movement of the freshwater-saltwater interface in the New Jersey coastal plain

    USGS Publications Warehouse

    Pope, Daryll A.; Gordon, Alison D.

    1999-01-01

    The confined aquifers of the New Jersey Coastal Plain are sands that range in thickness from 50 to 600 feet and are separated by confining units. The confining units are composed of silts and clays that range in thickness from 500 to 1,000 feet. The aquifers are recharged by precipitation on their outcrop areas. This water then flows laterally downdip and vertically to the deeper confined aquifers. The confined aquifers ultimately discharge to the Raritan and Delaware Bays and to the Atlantic Ocean. In 1988, ground-water withdrawals from confined and unconfined New Jersey Coastal Plain aquifers were approximately 345 million gallons per day, more than 75 percent of which was pumped from the confined aquifers. These withdrawals have created large cones of depression in several Coastal Plain aquifers near populated areas, particularly in Camden and Monmouth Counties. The continued decline of water levels in confined aquifers can cause saltwater intrusion, reduce stream discharge near the outcrop areas, and threaten the quality of the ground-water supply. SHARP, a quasi-three-dimensional finite-difference computer model that can simulate freshwater and saltwater flow, was used to simulate the ground-water flow system in the New Jersey Coastal Plain, including the location and movement of the freshwater-saltwater interface in nine aquifers and eight intervening confining units. The freshwater-saltwater interface is defined as the hypothetical line seaward of which the chloride concentration is equal to or greater than 10,000 milligrams per liter. Model simulations were used to estimate the location and movement of the freshwater-saltwater interface resulting from (1) eustatic sea-level changes over the past 84,000 years, (2) ground-water withdrawals from 1896 through 1988, (3) and future ground-water withdrawals from 1988 to 2040 from Coastal Plain aquifers. Simultion results showed that the location and movement of the freshwater-saltwater interface are more dependent

  5. Hydrogeology and extent of saltwater intrusion of the Great Neck peninsula, Great Neck, Long Island, New York

    USGS Publications Warehouse

    Stumm, Frederick

    2001-01-01

    Great Neck, a peninsula, in the northwestern part of Nassau County, N.Y., is underlain by unconsolidated deposits that form a sequence of aquifers and confining units. Seven public-supply wells have been affected by the intrusion of saltwater from the surrounding embayments (Little Neck Bay, Long Island Sound, Manhasset Bay). Fifteen observation wells were drilled in 1991-96 for the collection of hydrogeologic, geochemical, and geophysical data to delineate the subsurface geology and extent of saltwater intrusion within the peninsula. Continuous high-resolution seismic-reflection surveys in the embayments surrounding the Great Neck peninsula and the Manhasset Neck peninsula to the east were completed in 1993 and 1994. Two hydrogeologic units are newly proposed herein.the North Shore aquifer and the North Shore confining unit. The new drill-core data collected in 1991-96 indicate that the Lloyd aquifer, the Raritan confining unit, and the Magothy aquifer have been completely removed from the northern part of the peninsula by extensive glacial erosion. Water levels at selected observation wells were measured quarterly throughout the study. The results from two studies of the effects of tides on ground-water levels in 1992 and 1993 indicate that water levels at wells screened within the North Shore and Lloyd aquifers respond to tides and pumping effects, but those in the overlying upper glacial aquifer (where the water table is located) do not. Data from quarterly water-level measurements and the tidal-effect studies indicate the North Shore and Lloyd aquifers to be hydraulically connected. Offshore seismic-reflection surveys in the surrounding embayments indicate at least two glacially eroded buried valleys with subhorizontal, parallel reflectors indicative of draped bedding that is interpreted as infilling by silt and clay. The buried valleys (1) truncate the surrounding coarse-grained deposits, (2) are asymmetrical and steep sided, (3) trend northwest-southeast, (4

  6. Estimated effects of projected ground-water withdrawals on movement of the saltwater front in the Floridan aquifer, 1976-2000, west-central Florida

    USGS Publications Warehouse

    Wilson, William Edward

    1982-01-01

    Maps of observed 1976 and simulated 2000 potentiometric surfaces were used to estimate rates of saltwater encroachment and theoretical predevelopment equilibrium positions of the saltwater-freshwater interface in west-central Florida. The observed saltwater front, defined by the 19,000 milligrams-per-liter line of equal chloride concentration in the lower part of the Floridan aquifer, corresponds closely to a theoretical predevelopment equilibrium position of a saltwater-freshwater interface. The interface position was computed by the Ghyben-Herzberg method, using heads from a map of the predevelopment potentiometric surface. In maps of both the observed May 1976 and simulated May 2000 potentiometric surface, the saltwater front was within a large seasonal cone of depression in parts of Hillsborough, Manatee, and Sarasota Counties. Average landward flow rate of the front was computed to be 0.30 foot per day in May 1976 and 0.36 foot per day in May 2000. Seaward potentiometric-surface gradient under simulated October 2000 conditions averaged 8.8 x 10-5 foot per foot less than under observed September 1976 conditions. Regional observation wells are desirable for monitoring potentiometric-level changes in western Hardee County and eastern Manatee County and for monitoring water-quality changes along the saltwater front, on its landward side, from mid-Sarasota County northward to Hillsborough County. Net landward movement of the saltwater front in the lower part of the Floridan aquifer is probably occurring under existing conditions. Pumping during 1976-2000 would probably increase slightly the rate of movement. However, rates are so slow that on a regional basis saltwater encroachment under existing and projected conditions is not presently a threat to the existing freshwater resources. The maximum projected regional landward movement, under 'worst case' conditions, of the saltwater front between 1976 and 2000 is estimated to be about one-half mile. Significant local

  7. 3D modelling in salt tectonic context: the Crocodile minibasin in Sivas (Turkey)

    NASA Astrophysics Data System (ADS)

    Collon, Pauline; Pichat, Alexandre; Kergaravat, Charlie; Botella, Arnaud; Caumon, Guillaume; Favreau, Océane; Fuss, Gaétan; Godefroy, Gabriel; Lerat, Marine; Mazuyer, Antoine; Parquer, Marion; Charreau, Julien; Callot, Jean-Paul; Ringenbach, Jean-Claude

    2015-04-01

    Impermeable, with a low density and acting as a viscous fluid at the geological time scale, salt plays a unique tectonic role favouring hydrocarbon trap formations. Halokinetic structures are various and difficult to image with classic seismic techniques. Thus, outcrop analogues are precious and sought after. Since the re-interpretation in September 2011 of its evaporite deposits, the Oligo-Miocene basin of Sivas (Turkey) is a new choice analogue for the study of salt tectonic with outstanding outcrops reflecting the variety of salt related structures: minibasins, diapirs, welds... While studying these structures requires an important field work, building 3D models becomes an interesting way to better help understanding the three-dimensional organisation and to further perform numerical simulations (e.g., restoration, potential field measurement campaign simulation). The complex geometries observed in salt tectonic context make these 3D geological models particularly challenging to build, especially when only outcrops data are available. We focus on the Crocodile minibasin (Sivas) and present a modelling strategy using a subtle combination of recently developed techniques. Available data are: a Digital Elevation Model, satellite images and associated interpreted bedding traces on topography, orientation measurements of the strata and a conceptual interpretation. Located on an ancient salt extrusion, this minibasin is filled with lacustrine and sabkha sediments. It is interpreted with a closed synclinal structure on North. On its southern part, a central diapir has risen up, separating two tightened synclinals. The salt surface is modelled first as a triangulated surface using a classical explicit surface patch construction method and a manual post-process mesh improvement. Then, the minibasin sediments are modelled with an implicit approach that considers interfaces as equipotentials of a 3D scalar field. This requires to build a volumetric mesh conformable to the

  8. Decadal changes in bathymetry of the Yangtze River Estuary: Human impacts and potential saltwater intrusion

    NASA Astrophysics Data System (ADS)

    Wu, Shuaihu; Cheng, Heqin; Xu, Y. Jun; Li, Jiufa; Zheng, Shuwei

    2016-12-01

    This study analyzed bathymetric changes of the 77-km Yangtze River Estuary in China over the past ten years in order to understand the impacts of recent human activities on the estuary of a large alluvial river. Morphological changes were assessed by analyzing digitized bathymetric data of the estuarine channels from 2002 to 2013. Additionally, multi-beam bathymetric measurements made in 2012, 2014 and 2015 were utilized to investigate microtophographic bedforms of the lower reach of the estuary. Our results showed that the middle and upper reaches of the Yangtze River Estuary experienced substantial channel bed erosion in the past 10 years, and that the recent human activities have contributed to the change. These included the construction of a 70 km2 reservoir along the Yangtze River Estuary, the Qingcaosha Reservoir, for drinking water supply for the City of Shanghai, which has caused progressive bed erosion in the North Channel. The net volume of channel erosion in the Hengsha Passage from 2002 to 2013 was 0.86 × 108 m3. A large amount of the eroded sediment was trapped downstream, causing overall accretion in the upper reach of the North Passage. The middle and upper reaches of the South Passage also experienced intense erosion (0.45 × 108 m3) in the past ten years, while high accretion occurred in the lower reach because of the Deepening Waterway Project. The channel dredging left a large range of dredging marks and hollows in the North Passage. The increasing saltwater intrusion found in the Yangtze River Estuary may have been a consequence of either dredging or erosion, or both combined.

  9. Mitigation of saltwater intrusion by 'integrated fresh-keeper' wells combined with high recovery reverse osmosis.

    PubMed

    Khadra, Wisam M; Stuyfzand, Pieter J; Khadra, Ibrahim M

    2017-01-01

    Most countermeasures to mitigate saltwater intrusion in coastal, karstic or fractured aquifers are hindered by anisotropy, high transmissivities and complex dynamics. A coupled strategy is introduced here as a localized remedy to protect shallow freshwater reserves while utilizing the deeper intercepted brackish water. It is a double sourcing application where fresh-keeper wells are installed at the bottom of a deepened borehole of selected salinized wells, and then supported by high recovery RO desalination. The RO design has <1kWh/m(3) energy consumption, and up to 96% recovery in addition to low scaling propensity without use of any anti-scalant. A feasibility study is presented as an example for a salinizing, brackish well (TDS ~1600mg/L) in the Damour coastal aquifer in Lebanon. The concept is expected to produce ca. 1000m(3)/d of freshwater from this well by pumping 250m(3)/d of fresh groundwater from the top well screen and 800m(3)/d of brackish groundwater (to be later desalinized) from the fresh-keeper well screen below. Cost analysis shows that the capital cost could be returned back in 1 to 4years depending on the choice of produced water (bottled or tap) and available market. As an alternative, water from the RO plant could be blended with lower quality water, for instance untreated brackish groundwater (if unpolluted), to supply 3 more volumes for domestic use. The usage of brackish groundwater from integrated fresh-keeper wells thus serves 3 purposes: production of high quality drinking water, financial gain and mitigation of water stress by overpumping.

  10. Cost-efficient imaging and monitoring of saltwater in a shallow aquifer by using long electrode ERT

    NASA Astrophysics Data System (ADS)

    Ronczka, Mathias; Voß, Thomas; Günther, Thomas

    2015-11-01

    Electrical resistivity tomography (ERT) is an important method for imaging and monitoring saltwater intrusions into aquifers. Limitations regarding investigation depth can be overcome by using metal-cased boreholes as electrodes for characterising and monitoring groundwater salinity. We develop a scale-independent approach for imaging aquifers with long electrode ERT (LE-ERT). A synthetic study for a given electrode distribution is conducted to investigate model resolution properties for a complete and reduced data set. Results show that resistivity anomalies due to salinity variations can be imaged well, particularly if a-priori structural information is incorporated. The reduced data set exhibits a similar resolution of the given model compared with the complete data set. Repeated field measurements were conducted on a 500 × 300 m test site using 12 metal-cased boreholes. Additionally, seven surface electrodes were installed in order to increase model resolution. Data were inverted using a smoothness-constrained Gauss-Newton approach on a triangular prism mesh. Inversion results of a single survey of field data showed good agreement with geology known from boreholes and with results from standard surface ERT profiles. At the bottom of the first aquifer (about 40 m depth) a saltwater body was observed, predominantly in the eastern part. This finding is supported by in-situ fluid conductivity measurements. LE-ERT monitoring over a period of two years shows only little changes in the upper aquifer. Resistivity ratios between subsequent time steps indicate a slow dilution of the saltwater body which correlates with borehole fluid conductivity monitoring.

  11. Consequences and mitigation of saltwater intrusion induced by short-circuiting during aquifer storage and recovery in a coastal subsurface

    NASA Astrophysics Data System (ADS)

    Gerardus Zuurbier, Koen; Stuyfzand, Pieter Jan

    2017-02-01

    Coastal aquifers and the deeper subsurface are increasingly exploited. The accompanying perforation of the subsurface for those purposes has increased the risk of short-circuiting of originally separated aquifers. This study shows how this short-circuiting negatively impacts the freshwater recovery efficiency (RE) during aquifer storage and recovery (ASR) in coastal aquifers. ASR was applied in a shallow saltwater aquifer overlying a deeper, confined saltwater aquifer, which was targeted for seasonal aquifer thermal energy storage (ATES). Although both aquifers were considered properly separated (i.e., a continuous clay layer prevented rapid groundwater flow between both aquifers), intrusion of deeper saltwater into the shallower aquifer quickly terminated the freshwater recovery. The presumable pathway was a nearby ATES borehole. This finding was supported by field measurements, hydrochemical analyses, and variable-density solute transport modeling (SEAWAT version 4; Langevin et al., 2007). The potentially rapid short-circuiting during storage and recovery can reduce the RE of ASR to null. When limited mixing with ambient groundwater is allowed, a linear RE decrease by short-circuiting with increasing distance from the ASR well within the radius of the injected ASR bubble was observed. Interception of deep short-circuiting water can mitigate the observed RE decrease, although complete compensation of the RE decrease will generally be unattainable. Brackish water upconing from the underlying aquitard towards the shallow recovery wells of the ASR system with multiple partially penetrating wells (MPPW-ASR) was observed. This leakage may lead to a lower recovery efficiency than based on current ASR performance estimations.

  12. Environmental Assessment for Implementation of the Updated Integrated Natural Resources Management Plan Homestead Air Reserve Base, Homestead, Florida

    DTIC Science & Technology

    2009-12-01

    This is the American crocodile ( Crocody/us acutus), which is occasionally seen near the Twin Lakes area. On occasion, the federally listed wood...concern in Florida but federally listed as ’’threatened due to similarity of appearance" to the endangered American crocodile (Crocodylus actttus). While

  13. Effects of sea-level rise and pumpage elimination on saltwater intrusion in the Hilton Head Island area, South Carolina, 2004-2104

    USGS Publications Warehouse

    Payne, Dorothy F.

    2010-01-01

    Saltwater intrusion of the Upper Floridan aquifer has been observed in the Hilton Head area, South Carolina since the late 1970s and currently affects freshwater supply. Rising sea level in the Hilton Head Island area may contribute to the occurrence of and affect the rate of saltwater intrusion into the Upper Floridan aquifer by increasing the hydraulic gradient and by inundating an increasing area with saltwater, which may then migrate downward into geologic units that presently contain freshwater. Rising sea level may offset any beneficial results from reductions in groundwater pumpage, and thus needs to be considered in groundwater-management decisions. A variable-density groundwater flow and transport model was modified from a previously existing model to simulate the effects of sea-level rise in the Hilton Head Island area. Specifically, the model was used to (1) simulate trends of saltwater intrusion from predevelopment to the present day (1885-2004) and evaluate the conceptual model, (2) project these trends from the present day into the future based on different potential rates of sea-level change, and (3) evaluate the relative influences of pumpage and sea-level rise on saltwater intrusion. Four scenarios were simulated for 2004-2104: (1) continuation of the estimated sea-level rise rate over the last century, (2) a doubling of the sea-level rise, (3) a cessation of sea-level rise, and (4) continuation of the rate over the last century coupled with an elimination of all pumpage. Results show that, if present-day (year 2004) pumping conditions are maintained, the extent of saltwater in the Upper Floridan aquifer will increase, whether or not sea level continues to rise. Furthermore, if all pumpage is eliminated and sea level continues to rise, the simulated saltwater extent in the Upper Floridan aquifer is reduced. These results indicate that pumpage is a strong driving force for simulated saltwater intrusion, more so than sea-level rise at current rates

  14. Hydrogeology, simulation of regional ground-water flow, and saltwater intrusion, Potomac-Raritan-Magothy Aquifer System, Northern Coastal Plain of New Jersey

    USGS Publications Warehouse

    Pucci, Amleto A.; Pope, Daryll A.; Gronberg, JoAnn M.

    1994-01-01

    Chloride concentrations in well-water samples from the middle aquifer were as high as 6,000 mg/L in Sayreville Borough in 1987; concentrations in samples from drive-point wells from the same aquifer near the Washington Canal, the main source of saltwater, were as high as 7,100 mg/L. The migration of the saltwater front at about 470 feet per year to the southeast is influenced mainly by a thinning of the middle aquifer, which constrains flow, and by the locations of regional cones of depression caused by groundwater withdrawals.

  15. Vitread proliferation of filamentous processes in avian Müller cells and its putative functional correlates.

    PubMed

    Dreher, Z; Distler, C; Dreher, B

    1994-12-01

    In order to examine to what extent the neuronal and metabolic activities of avascular vertebrate retinae are reflected in the morphology of their Müller cells we have studied (by using several monoclonal antibodies) the morphology of Müller cells in two species of diurnal birds (chicken, Gallus domesticus, and pigeon, Columba livia) and one species of nocturnal saltwater crocodiles (Crocodylus porosi). In all three species, the outer nuclear layer is relatively thin and the Müller cell trunks divide into rootlets that wrap around the photoreceptors. In both diurnal birds studied, the trunks of Müller cells in the inner plexiform layers invariably divide into numerous fine filamentous processes that terminate in small expansions covering most of the vitreal surface of the retina. Furthermore, the networks of filamentous processes of birds' Müller cells exhibit conspicuous horizontal lamination in the inner plexiform layer. In contrast, the filamentous processes arising from the individual Müller cell trunks of the crocodile, if present, are much less numerous and less widely spread than those of diurnal birds. It is proposed that the splitting of the Müller cell trunks into numerous filamentous processes terminating in small vitreal expansions represents a morphological adaptation for: 1) effective spatial buffering of K+ ions in thick and presumably metabolically highly active, yet avascular, avian retinae, and 2) effective absorption and distribution of nutrients leaking from the vitreally located supplemental nutritive organ, the pecten.

  16. Risk of land degradation due to saltwater intrusion along the Venice coastland, Italy

    NASA Astrophysics Data System (ADS)

    Teatini, P.; Manoli, G.; Scudiero, E.; Deiana, R.; Perri, M.; Braga, F.; Tosi, L.; Putti, M.; Morari, F.

    2012-12-01

    The southern portion of the Venice coastland includes a very precarious environment. Due to an elevation down to 4 m below msl, the Venice Lagoon and Adriatic Sea proximity, and the encroachment of seawater from the mouth of the river network up to 20 km inland, salt contamination of land and groundwater is a severe problem that is seriously impacting the farmland productivity. An interdisciplinary multi-scale research is ongoing with the aim of understanding the contamination process, quantifying the effect of the saltwater intrusion of the crop production, and proposing possible mitigation strategies. A 25 ha basin cultivated with maize crop and representative of the area has been deeply monitored at various scales ranging from a few square meter plots up to the whole basin. Geophysical surveys, lab testing on soil and water samples, continuous measurements of hydrological parameters, physiological crop parameters, proximal sensing and multi-spectral remote sensing acquisitions, together with precise crop yield distribution were performed and acquired from 2010 to 2012. Geomorphological investigations, seismic and geo-electrical surveys combined with salt concentration measurements in the surficial waterbodies and groundwater (down to 10 m deep) are used to delineate the major pathways of seawater intrusion. Relationships existing between soil, water, crop factors and crop yield were identified, helping to assess plant stress at both the canopy and landscape level. The dataset is now used to set-up a three-dimensional numerical model of saturated/unsaturated water dynamics coupled with a crop-growth model. The model is applied at the basin scale to investigate the effects of water stress and soil contamination on the crop production. Once calibrated on hydrological records (e.g., groundwater levels, capillary pressure, etc.), crop growth, and yield production, the model will be applied to investigate expected scenarios related with the change of natural

  17. Saltwater contamination in the Venice Lagoon margin. Effects on soil productivity

    NASA Astrophysics Data System (ADS)

    Teatini, P.; Scudiero, E.; Braga, F.; Piragnolo, D.; Deiana, R.; Manoli, G.; Berti, A.; Morari, F.

    2011-12-01

    The Venice watershed includes a very precarious coastal environment subject to both natural and anthropogenic changes with a significant and economically important fraction of the coastal farmland presently below mean sea level. In the hydrogeological context of the Venice coastland, a large risk of saltwater contamination characterizes the southernmost area because of the geomorphological setting of the coastal plain. Salt contamination is influenced also by the activity of several pumping stations used to keep drained the area, groundwater withdrawals, irrigation and freshwater releases during summer dry months. The impact of salt intrusion from the salty water bodies on soil productivity has been studied in the years 2010-2011. In a 25 ha basin cultivated with maize crop, soil salinity (electrical conductivity 1:2) and the main physical-chemical properties of the soil (e.g. texture, pH, organic carbon and CSC) were measured along the 1.5 m soil profile in 120 positions. Maps of apparent electrical conductivity (ECa) at three different investigation depths (0 - 0.75 m; 0-1.50 m; 0- 6.00 m) were also obtained in April 2010 and April 2011 with a CMD electromagnetic conductivity meter (GF Instruments) associated to a DGPS. During the 2-year period some physiological crop parameters, in particular leaf reflectance (i.e. Spectrascan, Photoresearch) and leaf ions content were monitored across the study area. Moreover, maps of NDVI were obtained by proximal sensing (three dates each year) using an active spectral radiometer (Crop Circle, Holland Scientific) and remote sensing acquiring WorldView-2 satellite images at the end of July 2010 and beginning of July 2011. Finally, maps of the crop yield were obtained at the end of the growing seasons by a yield mapping system mounted on a combine harvester. Relationships existing between soil, crop factors and crop yield were identified applying a multivariate spatial model, helping to assess plant stress at both the canopy

  18. Simulation of groundwater flow and saltwater movement in the Onslow County area, North Carolina: predevelopment-2010

    USGS Publications Warehouse

    Fine, Jason M.; Kuniansky, Eve L.

    2014-01-01

    Onslow County, North Carolina, is located within the designated Central Coastal Plain Capacity Use Area (CCPCUA). The CCPCUA was designated by law as a result of groundwater level declines of as much as 200 feet during the past four decades within aquifers in rocks of Cretaceous age in the central Coastal Plain of North Carolina and a depletion of water in storage from increased groundwater withdrawals in the area. The declines and depletion of water in storage within the Cretaceous aquifers increase the potential for saltwater migration—both lateral encroachment and upward leakage of brackish water. Within the CCPCUA, a reduction in groundwater withdrawals over a period of 16 years from 2003 to 2018 is mandated. Under the CCPCUA rules, withdrawals in excess of 100,000 gallons per day from any of the Cretaceous aquifer well systems are subject to water-use reductions of as much as 75 percent. To assess the effects of the CCPCUA rules and to assist with groundwater-management decisions, a numerical model was developed to simulate the groundwater flow and chloride concentrations in the surficial Castle Hayne, Beaufort, Peedee, and Black Creek aquifers in the Onslow County area. The model was used to (1) simulate groundwater flow from 1900 to 2010; (2) assess chloride movement throughout the aquifer system; and (3) create hypothetical scenarios of future groundwater development. After calibration of a groundwater flow model and conversion to a variable-density model, five scenarios were created to simulate future groundwater conditions in the Onslow County area: (1) full implementation of the CCPCUA rules with three phases of withdrawal reductions simulated through 2028; (2) implementation of only phase 1 withdrawal reductions of the CCPCUA rules and simulated through 2028; (3) implementation of only phases 1 and 2 withdrawal reductions of the CCPCUA rules and simulated through 2028; (4) full implementation of the CCPCUA rules with the addition of withdrawals from

  19. Position of the saltwater-freshwater interface in the upper part of the Floridan Aquifer, southwest Florida, 1979

    USGS Publications Warehouse

    Causseaux, K.W.; Fretwell, J.D.

    1982-01-01

    The position of the saltwater-freshwater transition zone in the Floridan aquifer along coastal southwest Florida is depicted by the 250 milligram per liter line of equal chloride concentration in the upper producing zone of the aquifer. The line was interpolated from chloride concentration data for wells open to the upper producing zone of the aquifer and plotted on a map having a scale of 1:250,000. The line generally lies inland within 5 miles of the coast in areas extending from latitude 29 degrees in Citrus County southward to southern Hillsborough County. In Manatee and Sarasota Counties, the line generally lies with 2 miles of the coast, except in southern Sarasota County where it extends eastward along the Charlotte-DeSoto County line. Knowledge about the position and movement of the 250 milligram per liter line is significant in the effective management of the ground-water resources of coastal areas. The present position of the line will be used as a basis for detecting future movement of the saltwater-freshwater interface. (USGS)

  20. Optimal design of saltwater intrusion control systems by Global Interactive Response Surfaces: the Nauru island case study

    NASA Astrophysics Data System (ADS)

    Alberti, Luca; Oberto, Gabriele; Pianosi, Francesca; Castelletti, Andrea

    2013-04-01

    Infiltration galleries and scavenger wells are often constructed to prevent saltwater intrusion in coastal aquifers. The optimal design of these infrastructures can be framed as a multi-objective optimization problem balancing availability of fresh water supply and installation/operation costs. High fidelity simulation models of the flow and transport processes can be used to link design parameters (e.g. wells location, size and pumping rates) to objective functions. However, the incorporation of these simulation models within an optimization-based planning framework is not straightforward because of the computational requirements of the model itself and the computational limitations of the optimization algorithms. In this study we investigate the potential for the Global Interactive Response Surface (GIRS) methodology to overcome these technical limitations. The GIRS methodology is used to recursively build a non-dynamic emulator of the process-based simulation model that maps design options into objectives values and can be used in place of the original model to more quickly explore the design space. The approach is used to plan infrastructural interventions for controlling saltwater intrusion and ensuring sustainable groundwater supply for Nauru, a Pacific island republic in Micronesia. GIRS is used to emulate a SEAWAT density driven groundwater flow-and-transport simulation model. Results show the potential applicability of the proposed approach for optimal planning of coastal aquifers.

  1. A conceptual framework and monitoring strategy for movement of saltwater in the coastal plain aquifer system of Virginia

    USGS Publications Warehouse

    Mcfarland, E. Randolph

    2015-09-04

    The saltwater-movement monitoring strategy is limited and constrained. Relative monitoring needs among groundwater-production wells, and construction of observation wells, depend on the accuracy of previously mapped groundwater chloride iso-concentration surfaces. Production wells in similar proximity to saltwater can differ in aquifer hydraulic conductivity, rates of withdrawal, and screened-interval lengths. Only production wells making withdrawals reported to the Virginia Department of Environmental Quality have been accounted for; undocumented production wells can result in spurious changes in groundwater chloride concentration. Upconing observation wells should be as close as possible to corresponding production wells, so long as production wells are not damaged by borehole deviation. Projected locations of some lateral-intrusion observation wells may be precluded and require adjustment. Depths of upconing and lateral-intrusion observation wells may also require adjustment to be within the same aquifer as their corresponding production wells. Existing unused wells can be adapted as observation wells if differences from specified locations and construction are kept to a minimum and are accounted for. Where multiple production wells are in proximity, a modified monitoring approach may be needed to determine their net effect on changes in chloride concentration, and may require more than one lateral-intrusion observation well depending on the vertical positions of production-well screened intervals.

  2. Saltwater contamination in the managed low-lying farmland of the Venice coast, Italy: An assessment of vulnerability.

    PubMed

    Da Lio, Cristina; Carol, Eleonora; Kruse, Eduardo; Teatini, Pietro; Tosi, Luigi

    2015-11-15

    The original morphology and hydrogeology of many low-lying coastlands worldwide have been significantly modified over the last century through river diversion, embankment built-up, and large-scale land reclamation projects. This led to a progressive shifting of the groundwater-surficial water exchanges from naturally to anthropogenically driven. In this human-influenced hydrologic landscape, the saltwater contamination usually jeopardizes the soil productivity. In the coastland south of Venice (Italy), several well log measurements, chemical and isotope analyses have been performed over the last decade to characterize the occurrence of the salt contamination. The processing of this huge dataset highlights a permanent variously-shaped saline contamination up to 20km inland, with different conditions in relation with the various geomorphological features of the area. The results point out the important role of the land reclamation in shaping the present-day salt contamination and reveal the contribution of precipitation, river discharge, lagoon and sea water to the shallow groundwater in the various coastal sectors. Moreover, an original vulnerability map to salt contamination in relation to the farmland productivity has been developed taking into account the electrical conductivity of the upper aquifer in the worst condition, the ground elevation, and the distance from salt and fresh surface water sources. Finally, the study allows highlighting the limit of traditional investigations in monitoring saltwater contamination at the regional scale in managed Holocene coastal environments. Possible improvements are outlined.

  3. Biaxial Fatigue Crack Growth Behavior in Aluminum Alloy 5083-H116 Under Ambient Laboratory and Saltwater Environments

    NASA Astrophysics Data System (ADS)

    Perel, V. Y.; Misak, H. E.; Mall, S.; Jain, V. K.

    2015-04-01

    Crack growth of aluminum alloy 5083 was investigated when subjected to the in-plane biaxial tension-tension fatigue with stress ratio of 0.5 under ambient laboratory and saltwater environments. Cruciform specimens with a center hole, containing a notch and precrack at 45° to the specimen's arms, were tested in a biaxial fatigue test machine. Two biaxiality ratios, λ = 1 and λ = 1.5, were studied. For λ = 1, crack propagated along a straight line collinearly with the precrack, while for λ = 1.5 case, the crack path was curved and non-collinear with the precrack. Uniaxial fatigue tests were also conducted. Crack growth rates were faster under the biaxiality fatigue in comparison to uniaxial fatigue at a given crack driving force (Δ K I or Δ G) in both environments. Further, an increase in biaxiality ratio increased the crack growth rate, i.e., faster for λ = 1.5 case than λ = 1 case. Both biaxial fatigue and saltwater environment showed detrimental effects on the fatigue crack growth resistance of 5083, and its combination is highly detrimental when compared to uniaxial fatigue.

  4. Application and evaluation of electromagnetic methods for imaging saltwater intrusion in coastal aquifers: Seaside Groundwater Basin, California

    USGS Publications Warehouse

    Nenna, Vanessa; Herckenrather, Daan; Knight, Rosemary; Odlum, Nick; McPhee, Darcy

    2013-01-01

    Developing effective resource management strategies to limit or prevent saltwater intrusion as a result of increasing demands on coastal groundwater resources requires reliable information about the geologic structure and hydrologic state of an aquifer system. A common strategy for acquiring such information is to drill sentinel wells near the coast to monitor changes in water salinity with time. However, installation and operation of sentinel wells is costly and provides limited spatial coverage. We studied the use of noninvasive electromagnetic (EM) geophysical methods as an alternative to installation of monitoring wells for characterizing coastal aquifers. We tested the feasibility of using EM methods at a field site in northern California to identify the potential for and/or presence of hydraulic communication between an unconfined saline aquifer and a confined freshwater aquifer. One-dimensional soundings were acquired using the time-domain electromagnetic (TDEM) and audiomagnetotelluric (AMT) methods. We compared inverted resistivity models of TDEM and AMT data obtained from several inversion algorithms. We found that multiple interpretations of inverted models can be supported by the same data set, but that there were consistencies between all data sets and inversion algorithms. Results from all collected data sets suggested that EM methods are capable of reliably identifying a saltwater-saturated zone in the unconfined aquifer. Geophysical data indicated that the impermeable clay between aquifers may be more continuous than is supported by current models.

  5. Multi-channel resistivity investigations of the freshwater-saltwater interface: A new tool to study an old problem

    USGS Publications Warehouse

    Swarzenski, P.W.; Kruse, S.; Reich, C.; Swarzenski, W.V.

    2007-01-01

    It has been well established that fresh or brackish groundwater can exist both near and far from shore in many coastal and marine environments. The often permeable nature of marine sediments and the underlying bedrock provides abundant pathways for submarine groundwater discharge. While submarine groundwater discharge as a coastal hydrogeological phenomenon has been widely recognized, only recent advances in both geochemical tracers and geophysical tools have enabled a realistic, systematic quantification of the scales and rates of this coastal groundwater discharge. Here we present multichannel electrical resistivity results using both a time series, stationary cable that has 56 electrodes spaced 2 m apart, as well as a 120 m streaming resistivity cable that has two current-producing electrodes and eight potential electrodes spaced 10 m apart. As the cable position remains fixed in stationary mode, we can examine in high resolution tidal forcing on the freshwater-saltwater interface. Using a boat to conduct streaming resistivity surveys, relatively large spatial transects can be rapidly (travel speed -2-3 knots) acquired in shallow (-1-20 m) waters. Sediment formation factors, used to convert resistivity values to salinity, were calculated from porewater and sediment samples collected during the installation of an offshore well in Tampa Bay, Florida, USA. Here we examine the seabed resistivity from sites within Tampa Bay using both stationary and streaming configurations and discuss their overall effectiveness as a new tool to examine the dynamic nature of the freshwater-saltwater interface.

  6. Mitochondrial genomes and divergence times of crocodile newts: inter-islands distribution of Echinotriton andersoni and the origin of a unique repetitive sequence found in Tylototriton mt genomes.

    PubMed

    Kurabayashi, Atsushi; Nishitani, Takuma; Katsuren, Seiki; Oumi, Shohei; Sumida, Masayuki

    2012-01-01

    Crocodile newts, which constitute the genera Echinotriton and Tylototriton, are known as living fossils, and these genera comprise many endangered species. To identify mitochondrial (mt) genes suitable for future population genetic analyses for endangered taxa, we determined the complete nucleotide sequences of the mt genomes of the Japanese crocodile newt Echinotriton andersoni and Himalayan crocodile newt Tylototriton verrucosus. Although the control region (CR) is known as the most variable mtDNA region in many animal taxa, the CRs of crocodile newts are highly conservative. Rather, the genes of NADH dehydrogenase subunits and ATPase subunit 6 were found to have high sequence divergences and to be usable for population genetics studies. To estimate the inter-population divergence ages of E. andersoni endemic to the Ryukyu Islands, we performed molecular dating analysis using whole and partial mt genomic data. The estimated divergence ages of the inter-island individuals are older than the paleogeographic segmentation ages of the islands, suggesting that the lineage splits of E. andersoni populations were not caused by vicariant events. Our phylogenetic analysis with partial mt sequence data also suggests the existence of at least two more undescribed species in the genus Tylototriton. We also found unusual repeat sequences containing the 3' region of cytochrome apoenzyme b gene, whole tRNA-Thr gene, and a noncoding region (the T-P noncoding region characteristic in caudate mtDNAs) from T. verrucosus mtDNA. Similar repeat sequences were found in two other Tylototriton species. The Tylototriton taxa with the repeats become a monophyletic group, indicating a single origin of the repeat sequences. The intra-and inter-specific comparisons of the repeat sequences suggest the occurrences of homologous recombination-based concerted evolution among the repeat sequences.

  7. Hydrogeologic framework, availability of water supplies, and saltwater intrusion, Cape May County, New Jersey

    USGS Publications Warehouse

    Lacombe, Pierre J.; Carleton, Glen B.

    2002-01-01

    During 1960-90, saltwater intrusion forced the abandonment of at least 10 public-supply wells, 3 industrial-supply wells, and more than 100 domestic-supply wells in Cape May County, N.J. Actual or imminent ground-water contamination caused by land-use practices and human activities has forced the closure of at least six shallow public-supply wells and many domestic-supply wells. Freshwater in Cape May County flows in many small streams and is held in wetlands and natural and artificial ponds. More importantly, freshwater from precipitation passes through and is stored in five aquifers-- Holly Beach water-bearing zone, estuarine sand aquifer, Cohansey aquifer, Rio Grande water-bearing zone, and Atlantic City 800-foot sand. Surface-water discharges were measured at 14 stream sites. The Tuckahoe River is the largest stream in Cape May County. The mean annual discharge for the Tuckahoe River at Head of River was 43.8 ft3/s (cubic feet per second) or 10,800 Mgal/yr (million gallons per year) during the period of record (1969-93). Mean daily discharge ranged from 25 ft3/s or 16 Mgal/d in September to 73 ft3/s or 47 Mgal/d in April. Mean daily discharge at the eight largest streams wholly within the county ranged from 15.9 to 3.05 ft3/s (3,750 to 720 Mgal/yr). Total water use in the county was about 8,600 Mgal/yr in 1990, including about 25 Mgal/yr of surface water, 3,000 Mgal/yr from the Holly Beach water-bearing zone, 1,000 Mgal/yr from the estuarine sand aquifer, 2,200 Mgal/yr from the Cohansey aquifer, 200 Mgal/yr from the Rio Grande water-bearing zone, and 2,200 Mgal/yr from the Atlantic City 800-foot sand. Water-level data collected during April 1991 for more than 200 wells show that in some locations ground-water flow directions and rates have changed when compared with those shown on historical potentiometric-surface maps. In 1991, water levels in the Holly Beach water-bearing zone were nearly identical to levels prior to development. A cone of depression has

  8. Potential consequences of saltwater intrusion associated with Hurricanes Katrina and Rita: Chapter 6C in Science and the storms-the USGS response to the hurricanes of 2005

    USGS Publications Warehouse

    Steyer, Gregory D.; Perez, Brian C.; Piazza, Sarai C.; Suir, Glenn

    2007-01-01

    Hurricanes Katrina and Rita pushed salt water from the Gulf of Mexico well inland into freshwater marsh communities in coastal Louisiana. This paper describes the spatial extent of saltwater intrusion and provides an initial assessment of impacts (salt stress) to coastal marsh vegetation communities.

  9. Generation of enterococci bacteria in a coastal saltwater marsh and its impact on surf zone water quality.

    PubMed

    Grant, S B; Sanders, B F; Boehm, A B; Redman, J A; Kim, J H; Mrse, R D; Chu, A K; Gouldin, M; McGee, C D; Gardiner, N A; Jones, B H; Svejkovsky, J; Leipzig, G V; Brown, A

    2001-06-15

    Elevated levels of enterococci bacteria, an indicator of fecal pollution, are routinely detected in the surf zone at Huntington State and City Beaches in southern California. A multidisciplinary study was carried out to identify sources of enterococci bacteria landward of the coastline. We find that enterococci bacteria are present at high concentrations in urban runoff, bird feces, marsh sediments, and on marine vegetation. Surprisingly, urban runoff appears to have relatively little impact on surf zone water quality because of the long time required for this water to travel from its source to the ocean. On the other hand, enterococci bacteria generated in a tidal saltwater marsh located near the beach significantly impact surf zone water quality. This study identifies a potential tradeoff between restoring coastal wetlands and protecting beach water quality and calls into question the use of ocean bathing water standards based on enterococci at locations near coastal wetlands.

  10. Evolution of porosity in the saltwater freshwater mixing zone of coastal carbonate aquifers: An alternative modelling approach

    NASA Astrophysics Data System (ADS)

    Romanov, Douchko; Dreybrodt, Wolfgang

    2006-10-01

    SummaryDissolution of calcium carbonate in the saltwater-freshwater mixing zone in carbonate islands and coastal aquifers up to now has been treated by coupling geochemical equilibrium programmes to a reactive-transport model. The result is a complex nonlinearly coupled set of differential transport-advection equations, which need high computational efforts. If dissolution rates of calcite are sufficiently fast, such that one can assume the solution to be in equilibrium with respect to calcite a highly simplified modelling approach can be used. By use of the concept of Phillips in his book: Flow and Reactions in Permeable Rock, Cambridge University Press, New York (1991) and its more general formulation by De Simoni et al. [De Simoni, M., Carrera, J., Sánchez-Vila, X., Guadagnini, A., 2005. A procedure for the solution of multicomponent reactive transport problems, Water Resource Research, 41, W11410.], it is possible to decouple the complex set of equations. To calculate initial changes of porosity in the rock matrix one needs solely to solve the advection-transport equation for salinity s. Current codes on density driven flow such as SEAWAT can be used. To obtain the dissolution capacity of the mixed saltwater-freshwater solution the calcium equilibrium concentration ceq( s) is obtained as a function of salinity by PHREEQC-2. Initial porosity changes can then be calculated by a simple analytical expression of the gradient of the spatial distribution s( x, y) of salinity, the distribution of flow fluxes q( x, y) and the second derivative of the calcium equilibrium concentration ceq( s) with respect to salinity s. This approach does no longer require large dispersivities on the order of meters; but reasonable results are obtained with dispersivity on the scale of the pore size of the porous rock, which correctly describes mixing on the molecular scale. The method is applied to a simple 1-D-domain without convective flow and a constant gradient of salinity as

  11. Potential effects of deepening the St. Johns River navigation channel on saltwater intrusion in the surficial aquifer system, Jacksonville, Florida

    USGS Publications Warehouse

    Bellino, Jason C.; Spechler, Rick M.

    2013-01-01

    The U.S. Army Corps of Engineers (USACE) has proposed dredging a 13-mile reach of the St. Johns River navigation channel in Jacksonville, Florida, deepening it to depths between 50 and 54 feet below North American Vertical Datum of 1988. The dredging operation will remove about 10 feet of sediments from the surficial aquifer system, including limestone in some locations. The limestone unit, which is in the lowermost part of the surficial aquifer system, supplies water to domestic wells in the Jacksonville area. Because of density-driven hydrodynamics of the St. Johns River, saline water from the Atlantic Ocean travels upstream as a saltwater “wedge” along the bottom of the channel, where the limestone is most likely to be exposed by the proposed dredging. A study was conducted to determine the potential effects of navigation channel deepening in the St. Johns River on salinity in the adjacent surficial aquifer system. Simulations were performed with each of four cross-sectional, variable-density groundwater-flow models, developed using SEAWAT, to simulate hypothetical changes in salinity in the surficial aquifer system as a result of dredging. The cross-sectional models were designed to incorporate a range of hydrogeologic conceptualizations to estimate the effect of uncertainty in hydrogeologic properties. The cross-sectional models developed in this study do not necessarily simulate actual projected conditions; instead, the models were used to examine the potential effects of deepening the navigation channel on saltwater intrusion in the surficial aquifer system under a range of plausible hypothetical conditions. Simulated results for modeled conditions indicate that dredging will have little to no effect on salinity variations in areas upstream of currently proposed dredging activities. Results also indicate little to no effect in any part of the surficial aquifer system along the cross section near River Mile 11 or in the water-table unit along the cross

  12. Linking river, floodplain, and vadose zone hydrology to improve restoration of a coastal river affected by saltwater intrusion.

    PubMed

    Kaplan, D; Muñoz-Carpena, R; Wan, Y; Hedgepeth, M; Zheng, F; Roberts, R; Rossmanith, R

    2010-01-01

    Floodplain forests provide unique ecological structure and function, which are often degraded or lost when watershed hydrology is modified. Restoration of damaged ecosystems requires an understanding of surface water, groundwater, and vadose (unsaturated) zone hydrology in the floodplain. Soil moisture and porewater salinity are of particular importance for seed germination and seedling survival in systems affected by saltwater intrusion but are difficult to monitor and often overlooked. This study contributes to the understanding of floodplain hydrology in one of the last bald cypress [Taxodium distichum (L.) Rich.] floodplain swamps in southeast Florida. We investigated soil moisture and porewater salinity dynamics in the floodplain of the Loxahatchee River, where reduced freshwater flow has led to saltwater intrusion and a transition to salt-tolerant, mangrove-dominated communities. Twenty-four dielectric probes measuring soil moisture and porewater salinity every 30 min were installed along two transects-one in an upstream, freshwater location and one in a downstream tidal area. Complemented by surface water, groundwater, and meteorological data, these unique 4-yr datasets quantified the spatial variability and temporal dynamics of vadose zone hydrology. Results showed that soil moisture can be closely predicted based on river stage and topographic elevation (overall Nash-Sutcliffe coefficient of efficiency = 0.83). Porewater salinity rarely exceeded tolerance thresholds (0.3125 S m(-1)) for bald cypress upstream but did so in some downstream areas. This provided an explanation for observed vegetation changes that both surface water and groundwater salinity failed to explain. The results offer a methodological and analytical framework for floodplain monitoring in locations where restoration success depends on vadose zone hydrology and provide relationships for evaluating proposed restoration and management scenarios for the Loxahatchee River.

  13. Simulation of groundwater flow pathlines and freshwater/saltwater transition zone movement, Manhasset Neck, Nassau County, New York

    USGS Publications Warehouse

    Misut, Paul; Aphale, Omkar

    2014-01-01

    A density-dependent groundwater flow and solute transport model of Manhasset Neck, Long Island, New York, was used to analyze (1) the effects of seasonal stress on the position of the freshwater/saltwater transition zone and (2) groundwater flowpaths. The following were used in the simulation: 182 transient stress periods, representing the historical record from 1920 to 2011, and 44 transient stress periods, representing future hypothetical conditions from 2011 to 2030. Simulated water-level and salinity (chloride concentration) values are compared with values from a previously developed two-stress-period (1905–1944 and 1945–2005) model. The 182-stress-period model produced salinity (chloride concentration) values that more accurately matched the observed salinity (chloride concentration) values in response to hydrologic stress than did the two-stress-period model, and salinity ranged from zero to about 3 parts per thousand (equivalent to zero to 1,660 milligrams per liter chloride). The 182-stress-period model produced improved calibration statistics of water-level measurements made throughout the study area than did the two-stress-period model, reducing the Lloyd aquifer root mean square error from 7.0 to 5.2 feet. Decreasing horizontal and vertical hydraulic conductivities (fixed anisotropy ratio) of the Lloyd and North Shore aquifers by 20 percent resulted in nearly doubling the simulated salinity(chloride concentration) increase at Port Washington observation well N12508. Groundwater flowpath analysis was completed for 24 production wells to delineate water source areas. The freshwater/saltwater transition zone moved toward and(or) away from wells during future hypothetical scenarios.

  14. Simulated interaction between freshwater and saltwater and effects of ground-water pumping and sea-level change, lower Cape Cod aquifer system, Massachusetts

    USGS Publications Warehouse

    Masterson, John P.

    2004-01-01

    The U.S. Geological Survey, in cooperation with the National Park Service, Massachusetts Executive Office of Environmental Affairs, Cape Cod Commission, and the Towns of Eastham, Provincetown, Truro, and Wellfleet, began an investigation in 2000 to improve the understanding of the hydrogeology of the four freshwater lenses of the Lower Cape Cod aquifer system and to assess the effects of changing ground-water pumping, recharge conditions, and sea level on ground-water flow in Lower Cape Cod, Massachusetts. A numerical flow model was developed with the computer code SEAWAT to assist in the analysis of freshwater and saltwater flow. Model simulations were used to determine water budgets, flow directions, and the position and movement of the freshwater/saltwater interface. Model-calculated water budgets indicate that approximately 68 million gallons per day of freshwater recharge the Lower Cape Cod aquifer system with about 68 percent of this water moving through the aquifer and discharging directly to the coast, 31 percent flowing through the aquifer, discharging to streams, and then reaching the coast as surface-water discharge, and the remaining 1 percent discharging to public-supply wells. The distribution of streamflow varies greatly among flow lenses and streams; in addition, the subsurface geology greatly affects the position and movement of the underlying freshwater/saltwater interface. The depth to the freshwater/saltwater interface varies throughout the study area and is directly proportional to the height of the water table above sea level. Simulated increases in sea level appear to increase water levels and streamflows throughout the Lower Cape Cod aquifer system, and yet decrease the depth to the freshwater/saltwater interface. The resulting change in water levels and in the depth to the freshwater/saltwater interface from sea-level rise varies throughout the aquifer system and is controlled largely by non-tidal freshwater streams. Pumping from large

  15. Salt-water encroachment in southern Nassau and southeastern Queens Counties, Long Island, New York

    USGS Publications Warehouse

    Lusczynski, N.J.; Swarzenski, Wolfgang V.

    1966-01-01

    deposits. It extends from the seaward areas inland about 2 miles into Island Park. The deep wedge extends into southeastern Queens County and southern Nassau County principally in the deeper parts of the Magothy (?) Formation and in the underlying clay member of the Raritan Formation. The leading edge of the deep wedge is at the base of the Magothy (?) Formation. This edge is apparently at the shoreline east of Lido Beach and extends inland about 4 miles to Woodmere and about 7 miles to South Ozone Park. Zones of diffusion as much as 6 miles wide and about 500 feet thick were delineated in the frontal part of the salty-water wedges. These thick and broad zones of diffusion were probably formed during the past 1,000 or more years in heterogeneous unconsolidated deposits by long- and short-term changes in sea level and in fresh-water outflow to the sea and by dispersion caused by the movements of the water and its salt mass. Changes in sea level and fresh-water outflow together produced appreciable advances and recessions of the salt-water front. The chemical compositions of the diffused water in all wedges are modified to some extent by base exchange and other physical and chemical processes and also by diffusion. The intermediate wedge of salty water is moving landward at a rate of less than 20 feet a year in the vicinity of Island Park and, thus, has moved less than 1,000 feet since 1900. The leading edge of the deep wedge has advanced landward at about 300 feet a :ear in Woodmere in southwestern Nassau County and about 160 feet a year at South Ozone Park in southeastern Queens County, principally under the influence of local withdrawals near the toe of the wedge. Between Hewlett and Lido Beach, the deep wedge is moving inland at the rate of about 10 feet a year under the influence of regional withdrawals in inland areas. Regional encroachment of the deep wedge is apparently retarded appreciably by cyclic flow, that is, by the return seaward in the upper

  16. Hydrogeology, water quality, and saltwater intrusion in the Upper Floridan Aquifer in the offshore area near Hilton Head Island, South Carolina, and Tybee Island, Georgia, 1999-2002

    USGS Publications Warehouse

    Falls, W. Fred; Ransom, Camille; Landmeyer, James E.; Reuber, Eric J.; Edwards, Lucy E.

    2005-01-01

    To assess the hydrogeology, water quality, and the potential for saltwater intrusion in the offshore Upper Floridan aquifer, a scientific investigation was conducted near Tybee Island, Georgia, and Hilton Head Island, South Carolina. Four temporary wells were drilled at 7, 8, 10, and 15 miles to the northeast of Tybee Island, and one temporary well was drilled in Calibogue Sound west of Hilton Head Island. The Upper Floridan aquifer at the offshore and Calibogue sites includes the unconsolidated calcareous quartz sand, calcareous quartz sandstone, and sandy limestone of the Oligocene Lazaretto Creek and Tiger Leap Formations, and the limestone of the late Eocene Ocala Limestone and middle Avon Park Formation. At the 7-, 10-, and 15-mile sites, the upper confining unit between the Upper Floridan and surficial aquifers correlates to the Miocene Marks Head Formation. Paleochannel incisions have completely removed the upper confining unit at the Calibogue site and all but a 0.8-foot-thick interval of the confining unit at the 8-mile site, raising concern about the potential for saltwater intrusion through the paleochannel-fill sediments at these two sites. The paleochannel incisions at the Calibogue and 8-mile sites are filled with fine- and coarse-grained sediments, respectively. The hydrogeologic setting and the vertical hydraulic gradients at the 7- and 10-mile sites favored the absence of saltwater intrusion during predevelopment. After decades of onshore water use in Georgia and South Carolina, the 0-foot contour in the regional cone of depression of the Upper Floridan aquifer is estimated to have been at the general location of the 7- and 10-mile sites by the mid-1950s and at or past the 15-mile site by the 1980s. The upward vertical hydraulic gradient reversed, but the presence of more than 17 feet of upper confining unit impeded the downward movement of saltwater from the surficial aquifer to the Upper Floridan aquifer at the 7- and 10-mile sites. At the 10

  17. Application of the top specified boundary layer (TSBL) approximation to initial characterization of an inland aquifer mineralization 1. Direct contact between fresh and saltwater

    USGS Publications Warehouse

    Rubin, H.; Buddemeier, R.W.

    1998-01-01

    This paper presents a basic study in generalized terms that originates from two needs: (1) to understand the major mechanisms involved in the mineralization of groundwater of the Great Bend Prairie aquifer of Kansas by saltwater originating from a deeper Permian bedrock formation, and (2) to develop simple, robust tools that can readily be used for local assessment and management activities in the salt-affected region. A simplified basic conceptual model is adopted, incorporating two horizontal layers of porous medium which come into contact at a specific location within the model domain. The top layer is saturated with freshwater, and the bottom layer is saturated with saltwater. The paper considers various stages of approximation which can be useful for simplified simulation of the build-up of the transition zone (TZ) between the freshwater and the saltwater. The hierarchy of approximate approaches leads to the development of the top specified boundary layer (TSBL) method, which is the major tool used in this study for initial characterization of the development of the TZ. It is shown that the thickness of the TZ is mainly determined by the characteristic dispersivity. The build-up of the TZ is completed after a time period equal to the time needed to advect a fluid particle along the whole extent of the TZ. Potential applications and the effects of natural recharge and pumpage on salinity transport in the domain are discussed and evaluated in the context of demonstrating the practicality of the TSBL approach.

  18. Monitoring the saltwater intrusion by time lapse electrical resistivity tomography: The Chioggia test site (Venice Lagoon, Italy)

    NASA Astrophysics Data System (ADS)

    de Franco, R.; Biella, G.; Tosi, L.; Teatini, P.; Lozej, A.; Chiozzotto, B.; Giada, M.; Rizzetto, F.; Claude, C.; Mayer, A.; Bassan, V.; Gasparetto-Stori, G.

    2009-12-01

    A novel experiment of time lapse electrical resistivity tomography (TL-ERT) aimed at monitoring the dynamics of the saltwater intrusion in the coastland bounding the southern Venice Lagoon is presented. A dedicated apparatus was developed and operated for about 9 months from November 2005. The system acquired ten resistivity tomograms per day, five of which with high resolution by a 97.5 m long and 2.5 m electrode spacing ERT line, and five by a 300 m long and 5 m electrode spacing line down to 50-60 m depth. The stratigraphy of a 50 m deep borehole drilled in the nearby of the ERT-TL alignment outlines the presence of a shallow phreatic aquifer in the shallower 12 m thick unit, followed by a semi-confined aquifer between 18 and 38 m depth and a locally confined aquifer down to the bottom. The shallow aquifer is the most contaminated by the salt intrusion with a minimum value of the formation resistivity equal to 1.0 ohm m corresponding to a salinity of 25-30 gr/l. A seasonal resistivity fluctuation is observed, with the saltwater front that intrudes landward during the autumn-winter season and moves back seaward in spring-summer. The first semi-confined aquifer is characterized by resistivity value of about 5 ohm m, while the confined aquifer is less contaminated showing resistivity values greater than 7.5 ohm m. For both the two confined aquifers the resistivity value rises at the beginning of the summer probably due to the seasonal fresh water recharge supplied regionally from the mainland. The TL-ERT data have been correlated with a number of environmental variables. A relationship is found between the resistivity in the upper 3-4 m of the phreatic aquifer and the rainfalls, and between the water level in the adjacent main channel and the resistivity down to about 10 m depth. With respect to the tidal regime, a daily/weekly correlation with resistivity changes is not evidenced, while a significant negative correlation coefficient exists at monthly to seasonal

  19. Simulated effects of pumping and drought on ground-water levels and the freshwater-saltwater interface on the north fork of Long Island, New York

    USGS Publications Warehouse

    Misut, Paul E.; Schubert, Christopher E.; Bova, Richard G.; Colabufo, Steven R.

    2004-01-01

    Ground water is the sole source of freshwater on the North Fork of Long Island. Future demands for the limited freshwater supply during a prolonged drought could cause drawdowns that induce saltwater intrusion and render the supply unusable. The freshwater system on the North Fork contains several localized, hydraulically isolated aquifers bounded by salty water. The need for information on the ability of these aquifers to meet future demands prompted a 4-year study to develop a ground-water flow model to simulate several proposed pumping scenarios under long-term average conditions and during a hypothetical drought, and to delineate the resulting ground-water levels and movement of the freshwater-saltwater interface. The model code selected was SHARP, a quasi-three-dimensional finite-difference method of simulating freshwater and saltwater flow simultaneously.Two sets of four proposed pumping scenarios were evaluated. The first represented average recharge from precipitation during 2006-20; the second represented the same period and conditions except for a 5-year period of drought conditions. The average-recharge simulations used the long-term (1959-99) rate of recharge; the drought simulations applied a 20-percent reduction in recharge rate and a 20-percent increase in the 1999 rate of agricultural pumpage during 2011–15.The simulated movement of the freshwater-saltwater interface in future withdrawal and recharge scenarios indicates that the interface may rise beneath pumped wells at Inlet Drive, Brecknock Hall, Main Bayview Road, Islands End, North Road, and Alvah's Lane. Either (1) movement of the interface to within 50 feet of the well screen, (2) a large percent change in the distance between the interface and the well screen, or (3) movement of the interface through a clay layer is a cause for concern. Wellfields in which saltwater intrusion does not appear to be a cause for concern were those at Ackerly Pond, Kenney's Road, Middle Road, Rocky Point Road

  20. Effects of lowering interior canal stages on salt-water intrusion into the shallow aquifer in Southeast Palm Beach County, Florida

    USGS Publications Warehouse

    Land, Larry F.

    1975-01-01

    Land in southeast Palm Beach County is undergoing a large-scale change in use, from agricultural to residential. To accommodate residential use, a proposal has been made by developers to the Board of the Lake Worth Drainage District to lower the canal stages in the interior part of the area undergoing change. This report documents one of the possible effects of such lowering. Of particular interest to the Board was whether the lower canal stages would cause an increase in salt-water intrusion into the shallow aquifer along the coast. The two main tools used in the investigation were a digital model for aquifer evaluation and an analytical technique for predicting the movement of the salt-water front in response to a change of ground-water flow into the ocean. The method of investigation consisted of developing a digital ground-water flow model for three east-west test strips. They pass through the northern half of municipal well fields in Lake Worth, Delray Beach, and Boca Raton. The strips were first modeled with no change in interior canal stages. Then they were modeled with a change in canal stages of 2 to 4 feet (0.6 to 1.6 metres). Also, two land development schemes were tested. One was for a continuation of the present level of land development, simulated by continuing the present pumpage rates. The second scheme was for land development to continue until the maximum allowable densities were reached, simulated by increasing the pumping rates. The results of the test runs for an east-west strip through Lake Worth show that lowering part of the interior canal water levels 3 feet (1.0 metre), as done in 1961, does not affect the aquifer head or salt-water intrusion along the coastal area of Lake Worth. As a result, no effect in the coastal area would be expected as a result of canal stage lowering in other, interior parts of the study area. Results from the other test runs show that lowering interior canal water levels by as much as 4 feet (1.2 metres) would

  1. Simulated effects of pumping and drought on ground-water levels and the freshwater-saltwater interface on the north fork of Long Island, New York

    USGS Publications Warehouse

    Misut, Paul E.; Schubert, Christopher E.; Bova, Richard G.; Colabufo, Steven R.

    2004-01-01

    Ground water is the sole source of freshwater on the North Fork of Long Island. Future demands for the limited freshwater supply during a prolonged drought could cause drawdowns that induce saltwater intrusion and render the supply unusable. The freshwater system on the North Fork contains several localized, hydraulically isolated aquifers bounded by salty water. The need for information on the ability of these aquifers to meet future demands prompted a 4-year study to develop a ground-water flow model to simulate several proposed pumping scenarios under long-term average conditions and during a hypothetical drought, and to delineate the resulting ground-water levels and movement of the freshwater-saltwater interface. The model code selected was SHARP, a quasi-three-dimensional finite-difference method of simulating freshwater and saltwater flow simultaneously. Two sets of four proposed pumping scenarios were evaluated. The first represented average recharge from precipitation during 2006-20; the second represented the same period and conditions except for a 5-year period of drought conditions. The average-recharge simulations used the long-term (1959-99) rate of recharge; the drought simulations applied a 20-percent reduction in recharge rate and a 20-percent increase in the 1999 rate of agricultural pumpage during 2011-15. The simulated movement of the freshwater-saltwater interface in future withdrawal and recharge scenarios indicates that the interface may rise beneath pumped wells at Inlet Drive, Brecknock Hall, Main Bayview Road, Islands End, North Road, and Alvah?s Lane. Either (1) movement of the interface to within 50 feet of the well screen, (2) a large percent change in the distance between the interface and the well screen, or (3) movement of the interface through a clay layer is a cause for concern. Wellfields in which saltwater intrusion does not appear to be a cause for concern were those at Ackerly Pond, Kenney?s Road, Middle Road, Rocky Point Road

  2. Content of some metals in mean tissue of salt-water and fresh-water fish and in their products.

    PubMed

    Krełowska-Kułas, M

    1995-01-01

    The main goal of this work was to determine the concentration of some metals in meat tissue of salt-water and fresh-water fish and in their products. These studies refer to 13 species of fish most often eaten in Poland, caught in 1992. Fish (samples) for testing and examination were taken from each species once every month during the term of 6 months. The lead content in tested fish and their products did not exceed the set limits (0.6 mg Pb/kg), which were exceeded only in preserve from oyster. The average content of cadmium in flounder, Alaska pollack, Baltic herring, pickled herring pieces and in preserves with shrimp, crab and oyster exceeded the set limits (0.05 mg Cd/kg). The copper and zinc content in tested fish and their products is also within the set domestic limits (10.0 mg Cu/kg and 50.0 mg Zn/kg). The iron (3.6-24.2 mg/kg), magnesium (170-380 mg/kg) and manganese (0.12-0.31 mg/kg) contents in muscle tissue of the tested fish and their products seem to be typical. The presence of absolutely toxic metals (lead and cadmium) in some species of fish and their products points to extreme contamination of water environment by those metals.

  3. Social Perception of Public Water Supply Network and Groundwater Quality in an Urban Setting Facing Saltwater Intrusion and Water Shortages

    NASA Astrophysics Data System (ADS)

    Alameddine, Ibrahim; Jawhari, Gheeda; El-Fadel, Mutasem

    2017-04-01

    Perceptions developed by consumers regarding the quality of water reaching their household can affect the ultimate use of the water. This study identified key factors influencing consumers' perception of water quality in a highly urbanized coastal city, experiencing chronic water shortages, overexploitation of groundwater, and accelerated saltwater intrusion. Household surveys were administered to residents to capture views and perceptions of consumed water. Concomitantly, groundwater and tap water samples were collected and analyzed at each residence for comparison with perceptions. People's rating of groundwater quality was found to correlate to the measured water quality both in the dry and wet seasons. In contrast, perceptions regarding the water quality of the public water supply network did not show any correlation with the measured tap water quality indicators. Logistic regression models developed to predict perception based on salient variables indicated that age, apartment ownership, and levels of total dissolved solids play a significant role in shaping perceptions regarding groundwater quality. Perceptions concerning the water quality of the public water supply network appeared to be independent of the measured total dissolved solids levels at the tap but correlated to those measured in the wells. The study highlights misconceptions that can arise as a result of uncontrolled cross-connections of groundwater to the public supply network water and the development of misaligned perceptions based on prior consumption patterns, water shortages, and a rapidly salinizing groundwater aquifer.

  4. A novel method for rearing first-feeding larval zebrafish: polyculture with Type L saltwater rotifers (Brachionus plicatilis).

    PubMed

    Best, Jason; Adatto, Isaac; Cockington, Jason; James, Althea; Lawrence, Christian

    2010-09-01

    Promoting high rates of growth and survival can be a major challenge in zebrafish culture, especially during the first-feeding stage. Here we describe a new rearing technique in which zebrafish larvae are polycultured in static tanks with Type "L" saltwater rotifers (Brachionus plicatilis) for the first 5 days of feeding (days 5-9 postfertilization). To demonstrate the effectiveness of this technique, we conducted rearing trials using fish from two different strains: AB and nacre. Growth, survival, water quality, and rotifer density were assayed daily through the polyculture phase (days 5-9), and during the transition to standard rearing conditions (days 10-12). After that point, once the fish were fully integrated onto recirculating systems, parameters were measured once per week out to day 30. In all trials, the fish displayed high rates of growth and survival throughout the three phases (polyculture, transition, and recirculating flow), indicating that this method may be employed during the critical first-feeding stage to help improve rearing performance in zebrafish facilities. Additionally, water quality parameters observed during the polyculture phase of the trials reveal that early zebrafish larvae are much more tolerant of elevated levels of ammonia and salinity than previously believed.

  5. Altitude of the freshwater-saltwater interface in a regionally extensive coastal plain aquifer of Mississippi, Alabama, and Georgia

    USGS Publications Warehouse

    Strickland, Donald J.; Mahon, Gary L.

    1986-01-01

    Geophysical well logs from over 150 oil test and water wells in Mississippi, Alabama, and Georgia were examined and calculations of the dissolved solids concentration in ground water were made using the spontaneous potential deflection as a measure of ionic activity. The values derived from these calculations were used to prepare a map showing the altitude relative to sea level at which the concentration of dissolved solids in the groundwater reached 10,000 mg/L within a regionally extensive aquifer in Mississippi, Alabama, and Georgia. A dissolved solids concentration of 10,000 mg/L is used to delineate the interface between moderately saline and saline water; 10,000 mg/L dissolved solids was designated to delineate the freshwater-saltwater interface. For a finite difference computer flow model being used this interface represents the location where horizontal flow of freshwater is greatly diminished. 10 ,000 mg/L also is the lower limit for dissolved solids concentrations for water in target zones for injection wells. This 10,000 mg/L dissolved solids line is of value as a water quality indicator; although water containing 3,000 to 10,000 mg/L or more of dissolved solids is too saline for agricultural use (upper limit approximately 3,000 mg/L), it may be useful for some industrial purposes. Waters containing dissolved solids concentrations > 10,000 mg/L have little potential for any use involving human activities. (Lantz-PTT)

  6. Inferring spatial and temporal behavioral patterns of free-ranging manatees using saltwater sensors of telemetry tags

    USGS Publications Warehouse

    Castelblanco-Martínez, Delma Nataly; Morales-Vela, Benjamin; Slone, Daniel H.; Padilla-Saldívar, Janneth Adriana; Reid, James P.; Hernández-Arana, Héctor Abuid

    2015-01-01

    Diving or respiratory behavior in aquatic mammals can be used as an indicator of physiological activity and consequently, to infer behavioral patterns. Five Antillean manatees, Trichechus manatus manatus, were captured in Chetumal Bay and tagged with GPS tracking devices. The radios were equipped with a micropower saltwater sensor (SWS), which records the times when the tag assembly was submerged. The information was analyzed to establish individual fine-scale behaviors. For each fix, we established the following variables: distance (D), sampling interval (T), movement rate (D/T), number of dives (N), and total diving duration (TDD). We used logic criteria and simple scatterplots to distinguish between behavioral categories: ‘Travelling’ (D/T ≥ 3 km/h), ‘Surface’ (↓TDD, ↓N), ‘Bottom feeding’ (↑TDD, ↑N) and ‘Bottom resting’ (↑TDD, ↓N). Habitat categories were qualitatively assigned: Lagoon, Channels, Caye shore, City shore, Channel edge, and Open areas. The instrumented individuals displayed a daily rhythm of bottom activities, with surfacing activities more frequent during the night and early in the morning. More investigation into those cycles and other individual fine-scale behaviors related to their proximity to concentrations of human activity would be informative

  7. Social Perception of Public Water Supply Network and Groundwater Quality in an Urban Setting Facing Saltwater Intrusion and Water Shortages.

    PubMed

    Alameddine, Ibrahim; Jawhari, Gheeda; El-Fadel, Mutasem

    2017-04-01

    Perceptions developed by consumers regarding the quality of water reaching their household can affect the ultimate use of the water. This study identified key factors influencing consumers' perception of water quality in a highly urbanized coastal city, experiencing chronic water shortages, overexploitation of groundwater, and accelerated saltwater intrusion. Household surveys were administered to residents to capture views and perceptions of consumed water. Concomitantly, groundwater and tap water samples were collected and analyzed at each residence for comparison with perceptions. People's rating of groundwater quality was found to correlate to the measured water quality both in the dry and wet seasons. In contrast, perceptions regarding the water quality of the public water supply network did not show any correlation with the measured tap water quality indicators. Logistic regression models developed to predict perception based on salient variables indicated that age, apartment ownership, and levels of total dissolved solids play a significant role in shaping perceptions regarding groundwater quality. Perceptions concerning the water quality of the public water supply network appeared to be independent of the measured total dissolved solids levels at the tap but correlated to those measured in the wells. The study highlights misconceptions that can arise as a result of uncontrolled cross-connections of groundwater to the public supply network water and the development of misaligned perceptions based on prior consumption patterns, water shortages, and a rapidly salinizing groundwater aquifer.

  8. Immunohistochemical examination of intracerebral aquaporin-4 expression and its application for differential diagnosis between freshwater and saltwater drowning.

    PubMed

    An, Jun-Ling; Ishida, Yuko; Kimura, Akihiko; Kondo, Toshikazu

    2011-01-01

    Human brain samples were collected from 70 autopsy cases including 22 freshwater drowning (FWD), 26 saltwater drowning (SWD), and 22 non-drowning cases as controls. Then, immunohistochemical study combined with morphometry was carried out in order to examine the differential expression of AQP1 and AQP4 in the brain samples. Immunohistochemically, star-shaped cells bearing highly branched processes, often surrounding blood vessels, showed positive reactions for AQP1 and AQP4 in FWD, SWD, as well as control groups. Additionally, with double-color immunofluorescence analysis, AQP1- or AQP4-positive cells could be identified as GFAP-positive astrocytes. Moreover, AQP1-positive reaction was also observed in blood vessels. Morphometrically, there were no significant differences in AQP1 expression in astrocytes or in blood vessels among the three groups. In contrast, the average value of AQP4-positive astrocytes was significantly higher in FWD cases than in SWD and control groups. Moreover, AQP4 expression was significantly lower in SWD than in the control group (p < 0.05). Moreover, there was no significant correlation between post-submerged interval and AQP expression in drowning cases. Therefore, immunohistochemical analysis of intracerebral AQP4 expression would be forensically useful for differentiation between FWD and SWD.

  9. Quantitative saltwater modeling for validation of sub-grid scale LES turbulent mixing and transport models for fire

    NASA Astrophysics Data System (ADS)

    Maisto, Pietro; Marshall, Andre; Gollner, Michael

    2015-11-01

    A quantitative understanding of turbulent mixing and transport in buoyant flows is indispensable for accurate modeling of combustion, fire dynamics and smoke transport used in both fire safety design and investigation. This study describes the turbulent mixing behavior of scaled, unconfined plumes using a quantitative saltwater modeling technique. An analysis of density difference turbulent fluctuations, captured as the collected images scale down in resolution, allows for the determination of the largest dimension over which LES averaging should be performed. This is important as LES models must assume a distribution for sub-grid scale mixing, such as the ?-PDF distribution. We showed that there is a loss of fidelity in resolving the flow for a cell size above 0 . 54D* ; where D* is a characteristic length scale for the plume. Such a point represents the threshold above which the fluctuations start to monotonically grow. Turbulence statistics were also analyzed in terms of span-wise intermittency and time and space correlation coefficients. An unexpected condition for the core of the plume, where a substantial amount of ambient fluid (fresh water) is found, and the mixing process under buoyant conditions were found depending on the resolution of measurements used.

  10. Oviposition and larval habitat preferences of the saltwater mosquito, Aedes vigilax, in a subtropical mangrove forest in Queensland, Australia.

    PubMed

    Knight, Jon; Griffin, Lachlan; Dale, Pat; Phinn, Stuart

    2012-01-01

    Our aim was to investigate the oviposition and larval habitats of the saltwater mosquito Aedes vigilax (Skuse) (Diptera: Culicidae) in a mangrove forest system in subtropical Queensland, Australia. Eggshells (indicators of oviposition) and larvae were sampled in three habitat classes that were depicted in a schematic model. Two classes were in depressions or basins, either with hummocks or dense pneumatophore substrates, both of which retained water after tidal flooding. The third class was in freely flushed mangroves that corresponded with more frequent tidal connections than the depression classes. ANOVA and Tukey-Kramer tests were used to analyze the data. The null hypotheses were rejected: the hummock class was a significant habitat based on both eggshell and larval data. The conclusion was that mosquito production in the mangrove system was distributed unevenly between habitat classes, and that the hummock class had conditions suited to the requirements of the immature stages of Ae. vigilax. This research has the potential to inform mosquito management strategies by focusing treatment on the problem habitats and underpinning habitat modifications including reducing water retention in the basins.

  11. Oviposition and Larval Habitat Preferences of the Saltwater Mosquito, Aedes vigilax, in a Subtropical Mangrove Forest in Queensland, Australia

    PubMed Central

    Knight, Jon; Griffin, Lachlan; Dale, Pat; Phinn, Stuart

    2012-01-01

    Our aim was to investigate the oviposition and larval habitats of the saltwater mosquito Aedes vigilax (Skuse) (Diptera: Culicidae) in a mangrove forest system in subtropical Queensland, Australia. Eggshells (indicators of oviposition) and larvae were sampled in three habitat classes that were depicted in a schematic model. Two classes were in depressions or basins, either with hummocks or dense pneumatophore substrates, both of which retained water after tidal flooding. The third class was in freely flushed mangroves that corresponded with more frequent tidal connections than the depression classes. ANOVA and Tukey-Kramer tests were used to analyze the data. The null hypotheses were rejected: the hummock class was a significant habitat based on both eggshell and larval data. The conclusion was that mosquito production in the mangrove system was distributed unevenly between habitat classes, and that the hummock class had conditions suited to the requirements of the immature stages of Ae. vigilax. This research has the potential to inform mosquito management strategies by focusing treatment on the problem habitats and underpinning habitat modifications including reducing water retention in the basins. PMID:22938052

  12. Crocodile Chemistry by Crocodile Clips, Ltd.

    NASA Astrophysics Data System (ADS)

    Keith-Lucas, Lisa

    2000-10-01

    Simulations should help bridge the gap between concepts and laboratory experiences. Flexibility in quantities and forms are important, but so also is accuracy. This program is very flexible; even in its preliminary form there is so much control of quantities and concentrations, but the stoichiometry is not correct in every case. Combinations that do not react as they would in the laboratory can be misleading. As this product is a work in progress, another look would be needed when the final version is available.

  13. Simulation of Variable-Density Ground-Water Flow and Saltwater Intrusion beneath Manhasset Neck, Nassau County, New York, 1905-2005

    USGS Publications Warehouse

    Monti, Jack; Misut, Paul E.; Busciolano, Ronald

    2009-01-01

    The coastal-aquifer system of Manhasset Neck, Nassau County, New York, has been stressed by pumping, which has led to saltwater intrusion and the abandonment of one public-supply well in 1944. Measurements of chloride concentrations and water levels in 2004 from the deep, confined aquifers indicate active saltwater intrusion in response to public-supply pumping. A numerical model capable of simulating three-dimensional variable-density ground-water flow and solute transport in heterogeneous, anisotropic aquifers was developed using the U.S. Geological Survey finite-element, variable-density, solute-transport simulator SUTRA, to investigate the extent of saltwater intrusion beneath Manhasset Neck. The model is composed of eight layers representing the hydrogeologic system beneath Manhasset Neck. Four modifications to the area?s previously described hydrogeologic framework were made in the model (1) the bedrock-surface altitude at well N12191 was corrected from a previously reported value, (2) part of the extent of the Raritan confining unit was shifted, (3) part of the extent of the North Shore confining unit was shifted, and (4) a clay layer in the upper glacial aquifer was added in the central and southern parts of the Manhasset Neck peninsula. Ground-water flow and the location of the freshwater-saltwater interface were simulated for three conditions (time periods) (1) a steady-state (predevelopment) simulation of no pumping prior to about 1905, (2) a 40-year transient simulation based on 1939 pumpage representing the 1905-1944 period of gradual saltwater intrusion, and (3) a 60-year transient simulation based on 1995 pumpage representing the 1945-2005 period of stabilized withdrawals. The 1939 pumpage rate (12.1 million gallons per day (Mgal/d)) applied to the 1905-1944 transient simulation caused modeled average water-level declines of 2 and 4 feet (ft) in the shallow and deep aquifer systems from predevelopment conditions, respectively, a net decrease of 5

  14. Statistical Analysis of ITRAX XRF Data to Identify Marine Incursion, Sediment Source, and Saltwater Leaching in Tsunami Deposits

    NASA Astrophysics Data System (ADS)

    Kain, C. L.; Chague-Goff, C.; Goff, J. R.; Gadd, P.

    2015-12-01

    Geochemical investigation of fine-grained tsunami sediments has found that a characteristic salinity signature can be commonly found in tsunami deposits and underlying soils following an event. We extend this method to assess historic and paleotsunami deposits and investigate a wider range of particle sizes, with the aim of identifying whether salinity signatures are present and determining the source material of the deposits. Geochemical and mineralogical investigation of seven short cores was undertaken at four sites in New Zealand, where historic and/or palaeotsunami deposits were present as sand, silt or gravel layers intercalated between soils. Geochemical signatures were measured using a high-resolution ITRAX X-ray fluorescence (XRF) core scanner and results were analysed using Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA). We were able to explore the signatures of historical events, verify that prehistoric deposits were laid down by tsunamis, and compare these sediments with the background depositional environment. A t-test of means was applied for salinity marker elements (S, Cl, Br) in the soils immediately above and below tsunami sand layers, to test for evidence of saltwater leaching. The dominant mineralogy of the sediments was determined using portable X-ray diffraction and the data used to consider source material and interpret the corresponding XRF data. Geochemical signatures were found to be site specific, depending primarily on the composition of the material. PCA and HCA results clearly distinguished the signature of the tsunami deposits from the background material at each individual site and were able to confirm or deny palaeodeposits as tsunami-related, by comparison with the signatures of known events in the same core or nearby.

  15. Hydrogeology and Extent of Saltwater Intrusion in the Northern Part of the Town of Oyster Bay, Nassau County, New York: 1995–98

    USGS Publications Warehouse

    Stumm, Frederick; Lange, Andrew D.; Candela, Jennifer L.

    2004-01-01

    The Oyster Bay study area, in the northern part of Nassau County, N.Y., is underlain by unconsolidated deposits that form a sequence of aquifers and confining units. At least one production well has been affected by the intrusion of saltwater from Hempstead Harbor, Long Island Sound, and Cold Spring Harbor. Nineteen boreholes were drilled during 1995-98 for the collection of hydrogeologic, geochemical, and geophysical data to delineate the subsurface geology and the extent of saltwater intrusion. Continuous high-resolution marine-seismic-reflection surveys in the surrounding embayments of the Oyster Bay study area were conducted in 1996.New drill-core data indicate two hydrogeologic units—the North Shore aquifer and the North Shore confining unit—where the Lloyd aquifer, the Raritan confining unit, and the Magothy aquifer have been completely removed by glacial erosion.Water levels at 95 observation wells were measured quarterly during 1995–98. These data and continuous water-level records indicated that (1) the upper glacial (water-table) and Magothy aquifers are hydraulically connected and that their water levels did not respond to tidal fluctuations, and (2) the Lloyd and North Shore aquifers are hydraulically connected and their water levels responded to pumping and to tidal fluctuations.Marine seismic-reflection surveys in the surrounding embayments indicate at least four glacially eroded buried valleys with subhorizontal, parallel reflectors indicative of draped bedding that is interpreted as infilling by silt and clay. The buried valleys (1) truncate the surrounding coarse-grained deposits, (2) are asymmetrical and steep sided, (3) trend northwest-southeast, (4) are several miles long and about 1 mile wide, and (5) extend to more than 500 feet below sea level.Water samples taken during 1995–98 from three production wells and six observation wells screened in the upper glacial and Magothy aquifers contained volatile organic compounds in concentrations

  16. Hydrogeology and Extent of Saltwater Intrusion in the Northern Part of the Town of Oyster Bay, Nassau County, New York: 1995-98

    USGS Publications Warehouse

    Stumm, Frederick; Lange, Andrew D.; Candela, Jennifer L.

    2004-01-01

    The Oyster Bay study area, in the northern part of Nassau County, N.Y., is underlain by unconsolidated deposits that form a sequence of aquifers and confining units. At least one production well has been affected by the intrusion of saltwater from Hempstead Harbor, Long Island Sound, and Cold Spring Harbor. Nineteen boreholes were drilled during 1995-98 for the collection of hydrogeologic, geochemical, and geophysical data to delineate the subsurface geology and the extent of saltwater intrusion. Continuous high-resolution marine-seismic-reflection surveys in the surrounding embayments of the Oyster Bay study area were conducted in 1996. New drill-core data indicate two hydrogeologic units?the North Shore aquifer and the North Shore confining unit?where the Lloyd aquifer, the Raritan confining unit, and the Magothy aquifer have been completely removed by glacial erosion. Water levels at 95 observation wells were measured quarterly during 1995-98. These data and continuous water-level records indicated that (1) the upper glacial (water-table) and Magothy aquifers are hydraulically connected and that their water levels did not respond to tidal fluctuations, and (2) the Lloyd and North Shore aquifers are hydraulically connected and their water levels responded to pumping and to tidal fluctuations. Marine seismic-reflection surveys in the surrounding embayments indicate at least four glacially eroded buried valleys with subhorizontal, parallel reflectors indicative of draped bedding that is interpreted as infilling by silt and clay. The buried valleys (1) truncate the surrounding coarse-grained deposits, (2) are asymmetrical and steep sided, (3) trend northwest-southeast, (4) are several miles long and about 1 mile wide, and (5) extend to more than 500 feet below sea level. Water samples taken during 1995-98 from three production wells and six observation wells screened in the upper glacial and Magothy aquifers contained volatile organic compounds in concentrations

  17. The use of freshwater and saltwater animals to distinguish between the toxic effects of salinity and contaminants in irrigation drain water

    USGS Publications Warehouse

    Ingersoll, Christopher G.; Dwyer, F.J.; Burch, S.A.; Nelson, M.K.; Buckler, D.R.; Hunn, J.B.

    1992-01-01

    Irrigation drain waters entering Stillwater Wildlife Management Area (SWMA) in south-western Nevada contain elevated levels of salinity and several inorganic contaminants (As, B, Cu, Li, Mo, and Sr). Mortalities of fish and waterfowl at the management area are believed to be associated with the poor water quality of the drains. The objective of the present study was to use fresh-water and saltwater animals to distinguish between the toxic effects of salinity and contaminants in effluent samples collected from irrigation drain waters. Static acute effluent tests were conducted with water collected from four sites at SWMA. Animals acclimated or cultured in fresh water (fathead minnows, Pimephales promelas; amphipods, Hyalella azteca; cladocerans, Daphnia magna) and salt water (striped bass, Morone saxatilis; amphipods, Hyalella azteca; and cladocerans, Daphnia magna) were used to separate toxic effects of salinity from the effects of inorganic contaminants in the drain water. One drain water (TJ drain, salinity 19 parts per thousand (grams per liter), osmolality 503 mmol/kg, hardness 3,780 mg/L as CaCO3) was toxic only to freshwater animals and saltwater cultured daphnids; water from a receiving pond (Pintail Bay, salinity 23 g/L, osmolality 542 mmol/kg, hardness 830 mg/L as CaCO3) was toxic to both freshwater and saltwater animals. Acute tests conducted with reconstituted waters representative of the Pintail Bay sample indicated that atypical ion ratios were toxic to striped bass and amphipods, even without the addition of inorganic contaminants. However, the addition of inorganic contaminants representative of the Pintail Bay sample increased the toxicity of this reconstituted water. These findings indicate that the toxicity of the TJ drain sample was related mainly to elevated salinity and that the toxicity of the Pintail Bay sample was a function of inorganic contamination and atypical ion ratios in combination with elevated salinity.

  18. Vulnerbility of production wells in the Potomac-Raritan-Magothy aquifer system to saltwater intrusion from the Delaware River in Camden, Gloucester, and Salem Counties, New Jersey

    USGS Publications Warehouse

    Navoy, Anthony S.; Voronin, Lois M.; Modica, Edward

    2005-01-01

    The Potomac-Raritan-Magothy aquifer system is hydraulically connected to the Delaware River in parts of Camden and Gloucester Counties, New Jersey, and has more limited contact with the river in Salem County, New Jersey. The aquifer system is used widely for water supply, and 122 production wells that are permitted by the New Jersey Department of Environmental Protection to pump more than 100,000 gallons per year in the three counties are within 2 miles of the river. During drought, saltwater may encroach upstream from the Atlantic Ocean and Delaware Bay to areas where the aquifer system is recharged by induced infiltration through the Delaware River streambed. During the drought of the mid-1960's, water with a chloride concentration in excess of potability standards (250 mg/L (milligrams per liter)) encroached into the reach of the river that recharges the aquifer system. The vulnerability of the major production wells in the area to similar saltwater encroachment in the future is a concern to water managers. This vulnerability was evaluated by investigating two scenarios: (1) a one-time recurrence of the conditions approximating those that occurred in the1960's, and (2) the recurrence of those same conditions on an annual basis. Results of ground-water-flow simulation in conjunction with particle tracking and one-dimensional transport analysis indicate that the wells that are most vulnerable to saltwater intrusion are those in the Morris and Delair well fields in Camden County. A single 30-day event during which the concentration of dissolved chloride or sodium exceeds 2,098 mg/L or 407 mg/L, respectively, in the Delaware River would threaten the potability of water from these wells, given New Jersey drinking-water standards of 250 mg/L for dissolved chloride and 50 mg/L for dissolved sodium. This chloride concentration is about six times that observed in the river during the 1960's drought. An annually occurring 1-month event during which the concentrations of

  19. The phylogeography of trypanosomes from South American alligatorids and African crocodilids is consistent with the geological history of South American river basins and the transoceanic dispersal of Crocodylus at the Miocene

    PubMed Central

    2013-01-01

    Background Little is known about the diversity, phylogenetic relationships, and biogeography of trypanosomes infecting non-mammalian hosts. In this study, we investigated the influence of host species and biogeography on shaping the genetic diversity, phylogenetic relationship, and distribution of trypanosomes from South American alligatorids and African crocodilids. Methods Small Subunit rRNA (SSU rRNA) and glycosomal Glyceraldehyde Phosphate Dehydrogenase (gGAPDH) genes were employed for phylogenetic inferences. Trypanosomes from crocodilians were obtained by haemoculturing. Growth behaviour, morphology, and ultrastructural features complement the molecular description of two new species strongly supported by phylogenetic analyses. Results The inferred phylogenies disclosed a strongly supported crocodilian-restricted clade comprising three subclades. The subclade T. grayi comprised the African Trypanosoma grayi from Crocodylus niloticus and tsetse flies. The subclade T. ralphi comprised alligatorid trypanosomes represented by Trypanosoma ralphi n. sp. from Melanosuchus niger, Caiman crocodilus and Caiman yacare from Brazilian river basins. T. grayi and T. ralphi were sister subclades. The basal subclade T. terena comprised alligatorid trypanosomes represented by Trypanosoma terena n. sp. from Ca. yacare sharing hosts and basins with the distantly genetic related T. ralphi. This subclade also included the trypanosome from Ca. crocodilus from the Orinoco basin in Venezuela and, unexpectedly, a trypanosome from the African crocodilian Osteolaemus tetraspis. Conclusion The close relationship between South American and African trypanosomes is consistent with paleontological evidence of recent transoceanic dispersal of Crocodylus at the Miocene/Pliocene boundaries (4–5 mya), and host-switching of trypanosomes throughout the geological configuration of South American hydrographical basins shaping the evolutionary histories of the crocodilians and their trypanosomes

  20. The Origin and Early Evolution of Sauria: Reassessing the Permian Saurian Fossil Record and the Timing of the Crocodile-Lizard Divergence

    PubMed Central

    Ezcurra, Martín D.; Scheyer, Torsten M.; Butler, Richard J.

    2014-01-01

    Sauria is the crown-group of Diapsida and is subdivided into Lepidosauromorpha and Archosauromorpha, comprising a high percentage of the diversity of living and fossil tetrapods. The split between lepidosauromorphs and archosauromorphs (the crocodile-lizard, or bird-lizard, divergence) is considered one of the key calibration points for molecular analyses of tetrapod phylogeny. Saurians have a very rich Mesozoic and Cenozoic fossil record, but their late Paleozoic (Permian) record is problematic. Several Permian specimens have been referred to Sauria, but the phylogenetic affinity of some of these records remains questionable. We reexamine and review all of these specimens here, providing new data on early saurian evolution including osteohistology, and present a new morphological phylogenetic dataset. We support previous studies that find that no valid Permian record for Lepidosauromorpha, and we also reject some of the previous referrals of Permian specimens to Archosauromorpha. The most informative Permian archosauromorph is Protorosaurus speneri from the middle Late Permian of Western Europe. A historically problematic specimen from the Late Permian of Tanzania is redescribed and reidentified as a new genus and species of basal archosauromorph: Aenigmastropheus parringtoni. The supposed protorosaur Eorasaurus olsoni from the Late Permian of Russia is recovered among Archosauriformes and may be the oldest known member of the group but the phylogenetic support for this position is low. The assignment of Archosaurus rossicus from the latest Permian of Russia to the archosauromorph clade Proterosuchidae is supported. Our revision suggests a minimum fossil calibration date for the crocodile-lizard split of 254.7 Ma. The occurrences of basal archosauromorphs in the northern (30°N) and southern (55°S) parts of Pangea imply a wider paleobiogeographic distribution for the group during the Late Permian than previously appreciated. Early archosauromorph growth

  1. 2-D and 3-D Visualization of the Freshwater/Saltwater Mixing Front, and Zones of Preferential Groundwater Flow in the Karst Biscayne Coastal Aquifer using Electromagnetic Induction Techniques, Miami, Southeastern Florida.

    NASA Astrophysics Data System (ADS)

    Stalker, J. C.; Glaccum, R.

    2005-05-01

    The Biscayne aquifer is unconfined, composed primarily of Karst limestone, and underlies all of Miami-Dade County and much of Biscayne Bay in southeastern Florida. It is the sole source of drinking water for the 3 million inhabitants of the city of Miami and Miami-Dade County, as well as portions of Broward and Monroe Counties. Saltwater intrusion is a prominent problem for all coastal aquifers including the Biscayne aquifer. Simple and quick detection of the three-dimensional saltwater/freshwater interface has been problematic without the use of extensive sounding surveys or multiple well sampling. We are developing a technique combining rapid EM-31 surface surveys with EM-31 vertical soundings to model the depth to the saltwater/freshwater front at two sites located within a half mile of Biscayne Bay. The EM-31 has a maximum signal penetration of about 25ft allowing for accurate near shore surveys. Depths to the saltwater have ranged from over 25 ft inland to less than 2-3 ft near the Bay and saltwater mangroves. Changes in conductivity along survey lines of equal elevation that are equidistant from the Bay may indicate zones of preferential flow due to conduit networks or the presence of backfill, both of which exacerbate saltwater intrusion. All surveys show a rapid change from fresh to brackish water as you move toward the Bay indicating a shallow and abrupt mixing zone. Using a simple depth-modeling program, a wire frame contour map of the mixing zone can be constructed. This technique has proven to be a quick, inexpensive method for first-order hydrogeological and spatial analysis of the saltwater/freshwater interface. In an allied study we are using down-hole electromagnetic induction techniques with an EM-39 tool on existing wells, analyzing fluctuations in conductivity within the saltwater zone to look for zones of high permeability in the aquifer. Conductivity fluctuates within the mixing zone from brackish values to values equivalent to Biscayne Bay

  2. Molecular classification of an elasmobranch angiotensin receptor: quantification of angiotensin receptor and natriuretic peptide receptor mRNAs in saltwater and freshwater populations of the Atlantic stingray.

    PubMed

    Evans, Andrew N; Henning, Toni; Gelsleichter, James; Nunez, B Scott

    2010-12-01

    Among the most conserved osmoregulatory hormone systems in vertebrates are the renin-angiotensin system (RAS) and the natriuretic peptides (NPs). We examined the RAS and NP system in the euryhaline Atlantic stingray, Dasyatis sabina (Lesueur). To determine the relative sensitivity of target organs to these hormonal systems, we isolated cDNA sequences encoding the D. sabina angiotensin receptor (AT) and natriuretic peptide type-B receptor (NPR-B). We then determined the tissue-specific expression of their mRNAs in saltwater D. sabina from local Texas waters and an isolated freshwater population in Lake Monroe, Florida. AT mRNA was most abundant in interrenal tissue from both populations. NPR-B mRNA was most abundant in rectal gland tissue from both populations, and also highly abundant in the kidney of saltwater D. sabina. This study is the first to report the sequence of an elasmobranch angiotensin receptor, and phylogenetic analysis indicates that the D. sabina receptor is more similar to AT(1) vs. AT(2) proteins. This classification is further supported by molecular analysis of AT(1) and AT(2) proteins demonstrating conservation of AT(1)-specific amino acid residues and motifs in D. sabina AT. Molecular classification of the elasmobranch angiotensin receptor as an AT(1)-like protein provides fundamental insight into the evolution of the vertebrate RAS.

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

    PubMed

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

    2012-06-01

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

  4. Structural lipid changes and Na(+)/K(+)-ATPase activity of gill cells' basolateral membranes during saltwater acclimation in sea lamprey (Petromyzon marinus, L.) juveniles.

    PubMed

    Lança, Maria João; Machado, Maria; Ferreira, Ana Filipa; Quintella, Bernardo Ruivo; de Almeida, Pedro Raposo

    2015-11-01

    Seawater acclimation is a critical period for anadromous species and a process yet to be understood in lampreys. Considering that changes in lipid composition of the gill cells' basolateral membranes may disrupt the major transporter Na(+)K(+)-ATPase, the goal of this study was to detect changes at this level during juvenile sea lamprey seawater acclimation. The results showed that saltwater acclimation has a direct effect on the fatty acid composition of gill cells basolateral membrane's phospholipids. When held in full-strength seawater, the fatty acid profile of basolateral membrane's phospholipids suffered a restructure by increasing either saturation or the ratio between oleic acid and eicosapentaenoic acid. Simultaneously, the activity of Na(+)K(+)-ATPase revealed a significant and positive correlation with basolateral membrane's cholesterol content in the presence of highest salinity. Our results pointed out for lipid adjustments involving the functional transporter present on the gill cell basolateral membranes to ensure the role played by branchial Na(+)K(+)-ATPase in ion transport during saltwater acclimation process. The responses observed contributed to the strategy adopted by gill cell's basolateral membranes to compensate for osmotic and ionic stressors, to ensure the success of the process of seawater acclimation associated with the downstream trophic migration of juvenile sea lamprey.

  5. Three crocodilian genomes reveal ancestral patterns of evolution among archosaurs

    PubMed Central

    Green, Richard E; Braun, Edward L; Armstrong, Joel; Earl, Dent; Nguyen, Ngan; Hickey, Glenn; Vandewege, Michael W; St John, John A; Capella-Gutiérrez, Salvador; Castoe, Todd A; Kern, Colin; Fujita, Matthew K; Opazo, Juan C; Jurka, Jerzy; Kojima, Kenji K; Caballero, Juan; Hubley, Robert M; Smit, Arian F; Platt, Roy N; Lavoie, Christine A; Ramakodi, Meganathan P; Finger, John W; Suh, Alexander; Isberg, Sally R; Miles, Lee; Chong, Amanda Y; Jaratlerdsiri, Weerachai; Gongora, Jaime; Moran, Christopher; Iriarte, Andrés; McCormack, John; Burgess, Shane C; Edwards, Scott V; Lyons, Eric; Williams, Christina; Breen, Matthew; Howard, Jason T; Gresham, Cathy R; Peterson, Daniel G; Schmitz, Jürgen; Pollock, David D; Haussler, David; Triplett, Eric W; Zhang, Guojie; Irie, Naoki; Jarvis, Erich D; Brochu, Christopher A; Schmidt, Carl J; McCarthy, Fiona M; Faircloth, Brant C; Hoffmann, Federico G; Glenn, Travis C; Gabaldón, Toni; Paten, Benedict; Ray, David A

    2015-01-01

    To provide context for the diversifications of archosaurs, the group that includes crocodilians, dinosaurs and birds, we generated draft genomes of three crocodilians, Alligator mississippiensis (the American alligator), Crocodylus porosus (the saltwater crocodile), and Gavialis gangeticus (the Indian gharial). We observed an exceptionally slow rate of genome evolution within crocodilians at all levels, including nucleotide substitutions, indels, transposable element content and movement, gene family evolution, and chromosomal synteny. When placed within the context of related taxa including birds and turtles, this suggests that the common ancestor of all of these taxa also exhibited slow genome evolution and that the relatively rapid evolution of bird genomes represents an autapomorphy within that clade. The data also provided the opportunity to analyze heterozygosity in crocodilians, which indicates a likely reduction in population size for all three taxa through the Pleistocene. Finally, these new data combined with newly published bird genomes allowed us to reconstruct the partial genome of the common ancestor of archosaurs providing a tool to investigate the genetic starting material of crocodilians, birds, and dinosaurs. PMID:25504731

  6. Three crocodilian genomes reveal ancestral patterns of evolution among archosaurs.

    PubMed

    Green, Richard E; Braun, Edward L; Armstrong, Joel; Earl, Dent; Nguyen, Ngan; Hickey, Glenn; Vandewege, Michael W; St John, John A; Capella-Gutiérrez, Salvador; Castoe, Todd A; Kern, Colin; Fujita, Matthew K; Opazo, Juan C; Jurka, Jerzy; Kojima, Kenji K; Caballero, Juan; Hubley, Robert M; Smit, Arian F; Platt, Roy N; Lavoie, Christine A; Ramakodi, Meganathan P; Finger, John W; Suh, Alexander; Isberg, Sally R; Miles, Lee; Chong, Amanda Y; Jaratlerdsiri, Weerachai; Gongora, Jaime; Moran, Christopher; Iriarte, Andrés; McCormack, John; Burgess, Shane C; Edwards, Scott V; Lyons, Eric; Williams, Christina; Breen, Matthew; Howard, Jason T; Gresham, Cathy R; Peterson, Daniel G; Schmitz, Jürgen; Pollock, David D; Haussler, David; Triplett, Eric W; Zhang, Guojie; Irie, Naoki; Jarvis, Erich D; Brochu, Christopher A; Schmidt, Carl J; McCarthy, Fiona M; Faircloth, Brant C; Hoffmann, Federico G; Glenn, Travis C; Gabaldón, Toni; Paten, Benedict; Ray, David A

    2014-12-12

    To provide context for the diversification of archosaurs--the group that includes crocodilians, dinosaurs, and birds--we generated draft genomes of three crocodilians: Alligator mississippiensis (the American alligator), Crocodylus porosus (the saltwater crocodile), and Gavialis gangeticus (the Indian gharial). We observed an exceptionally slow rate of genome evolution within crocodilians at all levels, including nucleotide substitutions, indels, transposable element content and movement, gene family evolution, and chromosomal synteny. When placed within the context of related taxa including birds and turtles, this suggests that the common ancestor of all of these taxa also exhibited slow genome evolution and that the comparatively rapid evolution is derived in birds. The data also provided the opportunity to analyze heterozygosity in crocodilians, which indicates a likely reduction in population size for all three taxa through the Pleistocene. Finally, these data combined with newly published bird genomes allowed us to reconstruct the partial genome of the common ancestor of archosaurs, thereby providing a tool to investigate the genetic starting material of crocodilians, birds, and dinosaurs.

  7. Armadillos, Boatbills & Crocodiles.

    ERIC Educational Resources Information Center

    Berkovits, Annette; Greenblatt, Esther

    1980-01-01

    Recounts the unique partnership in science instruction developed between Nassau and Suffolk County (New York) schools and the Bronx Zoo to provide educational experiences for handicapped and mentally retarded students. Discussion focuses on a five-phase program developed for 200 elementary secondary students from Rosemary Kennedy Center through…

  8. Effects on saltwater organisms

    SciTech Connect

    Reish, D.J.; Oshida, P.S.; Wilkes, F.G.; Mearns, A.J.; Ginn, T.C.; Carr, R.S.

    1984-06-01

    A review of the literature reveals numerous articles dealing with the uptake of metals by marine organisms. Cadmium, copper, zinc, and methyl mercury have been shown to have toxic effects on fish, oysters, clams, lobsters, and other marine animals. Both genetic and environmental factors are involved in the accumulation of these metals. 237 references.

  9. Simulation of groundwater flow in the "1,500-foot" sand and "2,000-foot" sand and movement of saltwater in the "2,000-foot" sand of the Baton Rouge area, Louisiana

    USGS Publications Warehouse

    Heywood, Charles E.; Griffith, Jason M.

    2013-01-01

    Groundwater withdrawals have caused saltwater to encroach into freshwater-bearing aquifers beneath Baton Rouge, Louisiana. Groundwater investigations in the 1960s identified a freshwater-saltwater interface located at the Baton Rouge Fault, across which abrupt changes in water levels occur. Aquifers south of the fault generally contain saltwater, and aquifers north of the fault contain freshwater, though limited saltwater encroachment has been detected within 7 of the 10 aquifers north of the fault. The 10 aquifers beneath the Baton Rouge area, which includes East and West Baton Rouge Parishes, Pointe Coupee Parish, and East and West Feliciana Parishes, provided about 167 million gallons per day (Mgal/day) for public supply and industrial use in 2010. Groundwater withdrawals from an aquifer that is 2,000-feet (ft) deep in East Baton Rouge Parish (the “2,000-foot” sand of the Baton Rouge area) have caused water-level drawdown up to 356 ft and induced saltwater movement northward across the fault. Groundwater withdrawals from the “2,000-foot” sand averaged 23.9 Mgal/d during 2010. Saltwater encroachment threatens wells that are located about 3 miles north of the fault, where industrial withdrawals account for about 66 percent of the water withdrawn from the “2,000-foot” sand in East Baton Rouge Parish. Constant and variable-density groundwater models were developed with the MODFLOW and SEAWAT groundwater modeling codes to evaluate strategies to control saltwater migration, including changes in the distribution of groundwater withdrawals and installation of “scavenger” wells to intercept saltwater before it reaches existing production wells. Five hypothetical scenarios simulated the effects of different groundwater withdrawal options on groundwater levels within the “1,500-foot” sand and the “2,000-foot” sand and the transport of saltwater within the “2,000-foot” sand. Scenario 1 is considered a base case for comparison to the other four

  10. The saltwater-freshwater interface in the Tertiary limestone aquifer, southeast Atlantic outer-continental shelf of the U.S.A.

    USGS Publications Warehouse

    Johnston, R.H.

    1983-01-01

    Hydrologic testing in an offshore oil well abandoned by Tenneco, Inc., determined the position of the saltwater-freshwater interface in Tertiary limestones underlying the Florida-Georgia continental shelf of the U.S.A. Previous drilling (JOIDES and U.S.G.S. AMCOR projects) established the existence of freshwater far offshore in this area. At the Tenneco well 55 mi. (???88 km) east of Fernandina Beach, Florida, drill-stem tests made in the interval 1050-1070 ft. (320-326 m) below sea level in the Ocala Limestone recovered a sample with a chloride concentration of 7000 mg l-1. Formation water probably is slightly fresher. Pressure-head measurements indicated equivalent freshwater heads of 24-29 ft. (7.3-8.8 m) above sea level. At the coast (Fernandina Beach), a relatively thin transition zone separating freshwater and saltwater occurs at a depth of 2100 ft. (640 m) below sea level. Fifty-five miles (???88 km) offshore, at the Tenneco well, the base of freshwater is ???1100 ft. (???335 m) below sea level. The difference in approximate depth to the freshwater-saltwater transition at these two locations suggests an interface with a very slight landward slope. Assuming the Hubbert interface equation applies here (because the interface and therefore freshwater flow lines are nearly horizontal) the equilibrium depth to the interface should be 40 times the freshwater head above sea level. Using present-day freshwater heads along the coast in the Hubbert equation results in depths to the interface of less than the observed 2100 ft. (640 m). Substituting predevelopment heads in the equation yields depths greater than 2100 ft. (640 m). Thus the interface appears to be in a transient position between the position that would be compatible with present-day heads and the position that would be compatible with predevelopment heads. This implies that some movement of the interface from the predevelopment position has occurred during the past hundred years. The implied movement is

  11. Expression Profiles of Branchial FXYD Proteins in the Brackish Medaka Oryzias dancena: A Potential Saltwater Fish Model for Studies of Osmoregulation

    PubMed Central

    Yang, Wen-Kai; Kang, Chao-Kai; Chang, Chia-Hao; Hsu, An-Di; Lee, Tsung-Han; Hwang, Pung-Pung

    2013-01-01

    FXYD proteins are novel regulators of Na+-K+-ATPase (NKA). In fish subjected to salinity challenges, NKA activity in osmoregulatory organs (e.g., gills) is a primary driving force for the many ion transport systems that act in concert to maintain a stable internal environment. Although teleostean FXYD proteins have been identified and investigated, previous studies focused on only a limited group of species. The purposes of the present study were to establish the brackish medaka (Oryzias dancena) as a potential saltwater fish model for osmoregulatory studies and to investigate the diversity of teleostean FXYD expression profiles by comparing two closely related euryhaline model teleosts, brackish medaka and Japanese medaka (O. latipes), upon exposure to salinity changes. Seven members of the FXYD protein family were identified in each medaka species, and the expression of most branchial fxyd genes was salinity-dependent. Among the cloned genes, fxyd11 was expressed specifically in the gills and at a significantly higher level than the other fxyd genes. In the brackish medaka, branchial fxyd11 expression was localized to the NKA-immunoreactive cells in gill epithelia. Furthermore, the FXYD11 protein interacted with the NKA α-subunit and was expressed at a higher level in freshwater-acclimated individuals relative to fish in other salinity groups. The protein sequences and tissue distributions of the FXYD proteins were very similar between the two medaka species, but different expression profiles were observed upon salinity challenge for most branchial fxyd genes. Salinity changes produced different effects on the FXYD11 and NKA α-subunit expression patterns in the gills of the brackish medaka. To our knowledge, this report is the first to focus on FXYD expression in the gills of closely related euryhaline teleosts. Given the advantages conferred by the well-developed Japanese medaka system, we propose the brackish medaka as a saltwater fish model for

  12. Check-list of the pentastomid parasites crocodilians and freshwater chelonians.

    PubMed

    Junker, K; Boomker, J

    2006-03-01

    Based on published records and own data a summary is given of the geographical distribution of the currently known species of pentastomid parasites infecting crocodiles and alligators, as well as freshwater chelonians. A brief generic diagnosis is provided for each genus. Fourteen out of the currently 23 living crocodilian species have been recorded as being host to one or more pentastomes. Out of the 32 pentastome species six are considered species inquirendae. Presently, six genera of crocodilian pentastomes, Agema, Alofia, Leiperia, Sebekia, Selfia and Subtriquetra are recognized. African crocodiles harbour eight pentastome species, six of which have been recorded from the Nile crocodile, Crocodylus niloticus. Three species belong to the genus Sebekia, Alofia being represented by two and Leiperia by only one species. Two species, Alofia parva and Agema silvae-palustris, occur in the dwarf crocodile, Osteolaemus tetraspis, and the slender-snouted crocodile, Crocodylus cataphractus, exclusively, but a single Sebekia species is shared with the Nile crocodile. The genus Agema is endemic to the African region. Infective stages of the pentastome Subtriquetra rileyi, thought to utilize Nile crocodiles as final hosts, have been recovered only from fishes. The largest number of pentastome species is found in the Australasian region. Of these, the Indo-Pacific crocodile, Crocodylus porosus, harbours seven, representing the genera Alofia, Sebekia, Leiperia and Selfia. Selfia is exclusive to the latter host. The genus Subtriquetra has been reported from "Indian crocodiles", a term possibly referring to either Crocodylus palustris, Crocodylus porosus or Gavialis gangeticus. Ten species of pentastomes parasitizing the crocodilian genera Alligator, Caiman, Crocodylus and Melanosuchus have been recorded from the Neotropical region including the southern states of the North American continent. The two most wide-spread pentastome genera, Alofia and Sebekia, have been recorded

  13. Simulation of groundwater flow in the "1,500-foot" sand and "2,000-foot" sand, with scenarios to mitigate saltwater migration in the "2,000-foot" sand of the Baton Rouge area, Louisiana

    USGS Publications Warehouse

    Heywood, Charles E.; Griffith, Jason M.; Lovelace, John K.

    2014-01-01

    Groundwater withdrawals have caused saltwater to encroach into freshwater-bearing aquifers beneath Baton Rouge, Louisiana. Groundwater investigations in the 1960s identified a freshwater-saltwater interface located at the Baton Rouge Fault, across which abrupt changes in water levels occur. Aquifers south of the fault generally contain saltwater, and aquifers north of the fault contain freshwater, though limited saltwater encroachment has been detected within 7 of the 10 aquifers north of the fault. The 10 aquifers beneath the Baton Rouge area, which includes East and West Baton Rouge Parishes, Pointe Coupee Parish, and East and West Feliciana Parishes, provided about 167 million gallons per day (Mgal/d) for public supply and industrial use in 2010. Groundwater withdrawals from the “2,000-foot” sand in East Baton Rouge Parish have caused water-level drawdown as great as 356 feet (ft) and induced saltwater movement northward across the fault. Saltwater encroachment threatens industrial wells that are located about 3 miles north of the fault. Constant and variable-density groundwater models were developed with the MODFLOW and SEAWAT groundwater modeling codes to evaluate strategies to control saltwater migration, including changes in the distribution of groundwater withdrawals and installation of “scavenger” wells to intercept saltwater before it reaches existing production wells. Six hypothetical scenarios simulated the effects of different groundwater withdrawal options on groundwater levels within the “1,500-foot” sand and the “2,000-foot” sand and the transport of saltwater within the “2,000-foot” sand during 2008–47. Scenario 1 is considered a base case for comparison to the other five scenarios and simulates continuation of 2007 reported groundwater withdrawals. Scenario 2 simulates discontinuation of withdrawals from seven selected industrial wells located in the northwest corner of East Baton Rouge Parish and predicts that water levels

  14. Evolutionary history of trypanosomes from South American caiman (Caiman yacare) and African crocodiles inferred by phylogenetic analyses using SSU rDNA and gGAPDH genes.