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65-568: The Ipubi Formation contains little fossils, apart from an indeterminate Pelomedusoides turtle, but contains high levels of TOC and the formation is identified as a potential target for shale gas development. The Ipubi Formation was described as a member of the Santana Formation by Beurlen in 1971. Later revision of the stratigraphy elevated the members of the former Santana Formation to separate formations; Crato, Ipubi and Romualdo from base to top. The formations were subsequently included in

130-458: A Pelomedusoides turtle were found in the formation. The material, archived as CPCA 3560, consists of crushed fragments of the skull, a partial lower jaw and the carapace. The fossil was described in 2011 by Ribeiro Oliveira et al., who were unable to definitively assign the specimen to a specific genus . The same specimen was mentioned by Fielding et al. in 2005 and reported as Araripemys . Pelomedusoides The Pleurodira are one of

195-500: A moisture trap and halide scrubbers to remove water vapor and halides from the gas stream before it reaches the detector. These substances can interfere with the detection of the CO 2 gas. The HTCO method may be useful in those applications where difficult to oxidize compounds, or high molecular weight organics, are present as it provides almost complete oxidation of organics including solids and particulates small enough to be injected into

260-513: A cooling chamber, and finally into the detector. Usually, the detector used is a non-dispersive infrared spectrophotometer . By finding the total inorganic carbon and subtracting it from the total carbon content, the amount of organic carbon is determined. Chemical oxidation analysers inject the sample into a chamber with phosphoric acid followed by persulfate. The analysis is separated into two steps. One removes inorganic carbon by acidification and purging. After removal of inorganic carbon persulfate

325-484: A fresh to saline upper water layer), which affected the shallow lacustrine system. The deposition of thin, organic matter-rich mudstones probably occurred during higher water levels, which resulted in relatively low salinity waters and low detrital contribution to the inner lacustrine zones. Data collected from outcrops and boreholes indicate that the Ipubi Formation is separated from the underlying Crato Formation and

390-405: A lab-based measurement. TOC detection is an important measurement because of the effects it may have on the environment, human health, and manufacturing processes. TOC is a highly sensitive, non-specific measurement of all organics present in a sample. It, therefore, can be used to regulate the organic chemical discharge to the environment in a manufacturing plant. In addition, low TOC can confirm

455-568: A major sag phase, and is formed by two stratigraphic units: Palynomorph associations showed that the lacustrine system evolved in an arid –semiarid tropical area where the most characteristic flora consisted of conifers, Gnetales , Bennettitales and early angiosperms . The Ipubi Formation is characterized by containing abundant algal/bacterial-derived well-preserved organic matter . The pattern of organic matter accumulation and preservation corresponds well with cyclical paleoenvironmental changes (from anoxic to oxic bottom conditions and from

520-614: A maximum of approximately 300 - 400 micro-liters under special conditions; such as repetitive injections) of sample can be handled making the methods less sensitive than chemical oxidation methods capable of digesting as much as 10 times more sample. Also, the salt content of the samples do not combust, and so therefore, gradually build a residue inside the combustion tube eventually clogging the catalyst resulting in poor peak shapes, and degraded accuracy or precision, unless appropriate maintenance procedures are followed. The catalyst should be regenerated or replaced as needed. To avoid this problem

585-449: A more “selective” passage of the dissolved CO 2 gas and nothing else. This provides a more precise and accurate measurement of the organics that were converted to CO 2 . The non-dispersive infrared analysis (NDIR) method offers the only practical interference-free method for detecting CO 2 in TOC analysis. The principal advantage of using NDIR is that it directly and specifically measures

650-438: A positive or a negative interference to the actual TOC value, resulting in analytical error. Some of the interfering chemical species include Cl , HCO 3 , SO 3 , SO 2 , ClO 2 , and H . Small changes in pH and temperature fluctuations also contribute to inaccuracy. Membrane conductivity analyzers have improved upon the direct conductivity approach by incorporating the use of hydrophobic gas permeation membranes to allow

715-406: A relatively low maintenance, high sensitivity method for a wide range of applications. However, there are oxidation limitations of this method. Limitations include the inaccuracies associated with the addition of any foreign substance into the analyte and samples with high amounts of particulates. Performing "system blank" analysis, which is to analyze then subtract the amount of carbon contributed by

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780-441: A required test for purified water and water for injection (WFI). For this reason, TOC has found acceptance as a process control attribute in the biotechnology industry to monitor the performance of unit operations comprising water purification and distribution systems. As many of these biotechnology operations include the preparation of medicines, the U.S. Food and Drug Administration (FDA) enacts numerous regulations to protect

845-610: A sensitive NDIR detector. Same as the combustion analyser, the total carbon formed minus the inorganic carbon gives a good estimate of the total organic carbon in the sample. This method is often used in online applications because of its low maintenance requirements. TOC is the first chemical analysis to be carried out on potential petroleum source rock in oil exploration . It is very important in detecting contaminants in drinking water, cooling water, water used in semiconductor manufacturing, and water for pharmaceutical use. Analysis may be made either as an online continuous measurement or

910-594: A system of grabens and half grabens. It is represented by the Abaiara Formation , that includes shales, siltstones , sandstones and conglomerates 4) Post-Rift I phase - Aptian to Albian - characterized by thermal subsidence. The lowermost unit Barbalha Formation , represents a fluviolacustrine phase and is composed of red and gray shales, siltstones and claystones. The Santana Group was formed during this stage and comprises three stratigraphic units: 5) Post-rift II phase - Albian to Cenomanian - characterized by

975-428: A very limited analytical range. Membrane conductivity relies upon the filtering of the CO 2 prior to measuring it with a conductivity cell. Both methods analyze sample conductivity before and after oxidization, attributing this differential measurement to the TOC of the sample. During the sample oxidization phase, CO 2 (directly related to the TOC in the sample) and other gases are formed. The dissolved CO 2 forms

1040-420: A weak acid, thereby changing the conductivity of the original sample proportionately to the TOC in the sample. Conductivity analyses assume that only CO 2 is present within the solution. As long as this holds true, then the TOC calculation by this differential measurement is valid. However, depending on the chemical species present in the sample and their individual products of oxidation, they may present either

1105-412: Is acidified, usually with phosphoric acid, to turn all of the inorganic carbon into carbon dioxide as per the following reaction: This is then sent to a detector for measurement. The other half of the sample is injected into a combustion chamber which is raised to between 600–700 °C, some even up to 1200 °C. Here, all the carbon reacts with oxygen, forming carbon dioxide. It is then flushed into

1170-399: Is added and the sample is either heated or bombarded with UV light from a mercury vapor lamp. Free radicals form persulfate and react with any carbon available to form carbon dioxide. The carbon from both determination (steps) is either run through membranes which measure the conductivity changes that result from the presence of varying amounts of carbon dioxide, or purged into and detected by

1235-409: Is an analytical parameter representing the concentration of organic carbon in a sample. TOC determinations are made in a variety of application areas. For example, TOC may be used as a non-specific indicator of water quality , or TOC of source rock may be used as one factor in evaluating a petroleum play . For marine surface sediments average TOC content is 0.5% in the deep ocean, and 2% along

1300-424: Is measured over time as the gas flows through the detector. A second reference measurement that is non-specific to CO 2 is also taken and the differential result correlates to the CO 2 concentration in the detector at that moment. As the gas continues to flow into and out of the detector cell the sum of the measurements results in a peak that is integrated and correlated to the total CO 2 concentration in

1365-688: Is not susceptible to lower recoveries caused by turbidity in samples. The analysis of system blanks, necessary in all chemical procedures, is especially necessary with heated persulfate TOC methods because the method is so sensitive that reagents cannot be prepared with carbon contents low enough to not be detected. Persulfate methods are used in the analysis of wastewater, drinking water, and pharmaceutical waters. When used in conjunction with sensitive NDIR detectors heated persulfate TOC instruments readily measure TOC at single digit parts per billion (ppb) up to hundreds of parts per million (ppm) depending on sample volumes. Accurate detection and quantification are

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1430-1844: Is the oxidizer but the oxidation power of the reaction is magnified by the addition of a chemical oxidizer, which is usually a persulfate compound. The mechanisms of the reactions are as follows: Free radical oxidants formed: S 2 O 8 2 − ⟶ h v 2   S O 4 − ∙ {\displaystyle \mathrm {S} _{2}\mathrm {O} _{8}^{2-}{\underset {hv}{\longrightarrow }}2\ \mathrm {SO} _{4}^{-\bullet }} H 2 O ⟶ h v H + + O H ∙ {\displaystyle \mathrm {H} _{2}\mathrm {O} {\underset {hv}{\longrightarrow }}\mathrm {H} ^{+}+\mathrm {OH} ^{\bullet }} S O 4 − ∙ + H 2 O ⟶ S O 4 2 − + O H ∙ + H + {\displaystyle \mathrm {SO} _{4}^{-\bullet }+\mathrm {H} _{2}\mathrm {O} \longrightarrow \mathrm {SO} _{4}^{2-}+\mathrm {OH} ^{\bullet }+\mathrm {H} ^{+}} Excitation of organics: R ⟶ h v R ∗ {\displaystyle \mathrm {R} {\underset {hv}{\longrightarrow }}\mathrm {R} ^{*}} Oxidation of organics: R ∗ + S O 4 − ∙ + O H ∙ ⟶ n C O 2 + … {\displaystyle \mathrm {R} ^{*}+\mathrm {SO} _{4}^{-\bullet }+\mathrm {OH} ^{\bullet }\longrightarrow n\mathrm {CO} _{2}+\dots } The UV–chemical oxidation method offers

1495-439: Is treated for disinfection , TOC provides an estimate of the amount of NOM in the water source. In water treatment facilities, source water is subject to reaction with chlorine-containing disinfectants. When the raw water is chlorinated, active chlorine compounds (Cl 2 , HOCl, ClO ) react with NOM to produce chlorinated disinfection byproducts (DBPs). Researchers have determined that higher levels of NOM in source water during

1560-902: The Cariri Formation , that include medium to coarse-grained quartz sandstones , locally conglomeratic , deposited in large braided fluvial systems 2) Pre-rift phase - Tithonian - characterized by the mechanical subsidence due to lithosphere thinning that preceded the rift. It is represented by the Brejo Santo Formation , that comprises red shales and claystones , and the Missão Velha Formation , constituted by medium to coarse-grained quartz-feldspathic sandstones, locally conglomeratic, that contains entire trunks and fragments of silicified wood ( Dadoxilon benderi ) conifer 3) Rift phase - Berriasian to Hauterivian - characterized by increasing mechanical subsidence that created

1625-726: The Pelomedusidae , also known as the African mud terrapins, and the Podocnemididae , also known as the American side-neck river turtles. However, they were cosmopolitan clade during the Cretaceous and most of the Cenozoic , and even occurred in marine environments around the world. The Pleurodira are identified by the method with which they withdraw their heads into their shells. In these turtles,

1690-649: The Santana Group , representing the middle part of the formerly described Araripe Group. The tectono-sedimentary evolution of the Araripe Basin, located in the Borborema Geologic Province, encompasses four stages, with five tectonostratigraphic phases: 1) Syneclise phase - Silurian to Devonian - characterized by tectonic quiescence in the Borborema Province. It is represented by the deposits of

1755-456: The cervical vertebrae . All extant turtles studied so far have eight vertebrae in the neck. In the Pleurodira, these vertebrae are narrow in cross-section and spool-shaped with biconvex centra on one or more of the cervicals. These centra act as a double joint, allowing a large degree of sideways movement and providing a means of folding the neck onto itself in the lateral plane. Conversely, in

1820-612: The side-necked turtles and the name Pleurodira quite literally translates to side neck, whereas the Cryptodira are known as hidden-necked turtles. The Pleurodira turtles are currently restricted to freshwater habitats in the Southern Hemisphere, largely to Australia, South America, and Africa. Within the Pleurodira, three living families are represented: Chelidae , also known as the Austro-South American side-necked turtles,

1885-406: The CO 2 formed when organic carbon is oxidized and/or when inorganic carbon is acidified. Oxidation is performed either through Pt-catalyzed combustion, by heated persulfate, or with a UV / persulfate reactor. Once the CO 2 is formed, it is measured by a detector: either a conductivity cell (if the CO 2 is aqueous) or a non-dispersive infrared cell (after purging the aqueous CO 2 into

1950-455: The CO 2 generated by oxidation of the organic carbon in the oxidation reactor , rather than relying on a measurement of a secondary, corrected effect, such as used in conductivity measurements. A traditional NDIR detector relies upon flow-through-cell technology, where the oxidation product flows into and out of the detector continuously. A region of absorption of infrared light specific to CO 2 , usually around 4.26 μm (2350 cm ),

2015-405: The Cryptodira, the neck bones are wide and flat. The biconvex centra in some of the cryptodiran cervicals allow the neck to fold onto itself in the vertical plane. Pleurodirans also differ from cryptodirans in the emarginations of their skulls. Skull emargination provides room and anchorage for the jaw muscles. The connection points and the position of the emarginations relate to different bones of

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2080-629: The Instrumentation Testing Association (ITA) can provide results of field testing online TOC analysers in an industrial wastewater application. Gulf Coast Waste Disposal Authority (GCWDA), Bayport Industrial Wastewater Treatment Plant in Pasadena, Texas sponsored and conducted this test in 2011. The GCWDA Bayport facility treats approximately 30 mgd of industrial waste received from approximately 65 customers (primarily petrochemical). Field tests consisted of operating online TOC analysers at

2145-439: The Ipubi Formation represents a transition from a transgressive systems tract to a maximum flooding surface . Six stages in the depositional cycle were described by Fabin et al. in 2018: While the underlying Crato and overlying Romualdo Formations are particularly rich in fossils, comprising flora, fish, arthropods, insects, snakes, turtles, dinosaurs and pterosaurs, the Ipubi Formation contains little fossil material. Fossils of

2210-736: The absence of potentially harmful organic chemicals in water used to manufacture pharmaceutical products. TOC is also of interest in the field of potable water purification due to byproducts of disinfection. Inorganic carbon poses little to no threat. Since the early 1970s, TOC has been an analytic technique used to measure water quality during the drinking water purification process. TOC in source waters comes from decaying natural organic matter (NOM) as well as synthetic sources. Humic acid , fulvic acid, amines , and urea are examples of NOM. Some detergents , pesticides , fertilizers , herbicides , industrial chemicals, and chlorinated organics are examples of synthetic sources. Before source water

2275-424: The air by a purge step. The remaining non-purgeable organic carbon (NPOC) contained in the liquid aliquot is then oxidized releasing the CO 2 gases. These gases are then sent to the detector for measurement. This method is also referred to as the direct TOC method. A further variant employs acidification of the sample to evolve carbon dioxide and measuring it as inorganic carbon (IC), then oxidizing and measuring

2340-421: The amount of carbon in a water sample. By acidifying the sample and flushing with nitrogen or helium the sample removes inorganic carbon, leaving only organic carbon sources for measurement. There are two types of analysers. One uses combustion and the other chemical oxidation. This is used as a water purity test, as the presence of bacteria introduces organic carbon. A non-profit research and testing organization,

2405-552: The amount of inorganic carbon (IC) evolved from an acidified aliquot of a sample and also the amount of total carbon (TC) present in the sample. TOC is calculated by subtraction of the IC value from the TC of the sample. Another method directly measures TOC in the sample by acidifying the sample to a pH value of two or less to release the CO 2 gas by decomposition of the carbonates and vent these gases to

2470-746: The analysis of TOC is by TC-IC or NPOC methods, it may be broken into three main stages: Addition of acid and inert-gas sparging allows all bicarbonate and carbonate ions to be converted to carbon dioxide, and this IC product vented along with any purgeable organic carbon (POC) that was present. The second stage is the oxidation of the carbon in the remaining sample in the form of carbon dioxide (CO 2 ) and other gases. Modern TOC analyzers perform this oxidation step by several processes: Prepared samples are combusted from 1000 up to 1200 degrees C in an oxygen -rich atmosphere. All carbon present converts to carbon dioxide, flows through scrubber tubes to remove interferences such as chlorine gas, and water vapor , and

2535-451: The carbon dioxide is measured either by absorption into a strong base then weighed, or using an infrared detector . Most modern analyzers use non- dispersive infrared (NDIR) for detection of the carbon dioxide. Compared to the conventional high temperature catalytic oxidation, the great benefit of the combustion-method is the high oxidation power, so that oxidation-promoting catalysts are superfluous. A manual or automated process injects

2600-405: The chemical additive, inaccuracies are lowered. However, analyses of levels below 200 ppb TOC are still difficult. Also known as heated persulfate, the method utilizes the same free radical formation as UV persulfate oxidation except uses heat to magnify the oxidizing power of persulfate. Chemical oxidation of carbon with a strong oxidizer, such as persulfate, is highly efficient, and unlike UV,

2665-462: The development of biofilms on pipeline walls and biofilm growth within pharmaceutical water distribution systems. A correlation is believed to exist between TOC concentrations and the levels of endotoxins and microbes. Sustaining low TOC levels helps to control levels of endotoxins and microbes and thereby the development of biofilms. The United States Pharmacopoeia (USP), European Pharmacopoeia (EP) and Japanese Pharmacopoeia (JP) recognize TOC as

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2730-448: The disinfection process will increase the amount of carcinogens in the processed drinking water. With passage of the U.S. Safe Drinking Water Act in 2001, TOC analysis emerged as a quick and accurate alternative to the classical but more lengthy biological oxygen demand (BOD) and chemical oxygen demand (COD) tests traditionally reserved for assessing the pollution potential of wastewaters . Today, environmental agencies regulate

2795-477: The eastern margins. A typical analysis for total carbon (TC) measures both the total organic carbon (TOC) present and the complementing total inorganic carbon (TIC), the latter representing the amount of non-organic carbon, like carbon in carbonate minerals. Subtracting the inorganic carbon from the total carbon yields TOC. Another common variant of TOC analysis involves removing the TIC portion first and then measuring

2860-618: The entirety of the oxidation products of the sample in one reading, compared to flow-through cell technology. The output signal is proportional to the concentration of CO 2 in the carrier gas, from the oxidation of the sample aliquot. UV/ Persulfate oxidation combined with NDIR detection provides good oxidation of organics, low instrument maintenance, good precision at ppb levels, relatively fast sample analysis time and easily accommodates multiple applications, including purified water (PW), water for injection (WFI), CIP, drinking water and ultra-pure water analyses. Virtually all TOC analysers measure

2925-455: The furnace. The major drawback of HTCO analysis is its unstable baseline resulting from the gradual accumulation of non- volatile residues within the combustion tube. These residues continuously change TOC background levels requiring continuous background correction. Because aqueous samples are injected directly into a very hot, usually quartz , furnace only small aliquots (less than 2 milliliters and usually less than 50 - 100 microliter, with

2990-515: The gaseous phase). Conductivity detection is only desirable in the lower TOC ranges in deionized waters, whereas NDIR detection excels in all TOC ranges. A variation described as "membrane conductometric detection can allow for measurement of TOC across a wide analytical range in both deionized and non-deionized water samples. Modern high-performance TOC instruments are capable of detecting carbon concentrations well below 1 μg/L (1 part per billion or ppb). A total organic carbon analyser determines

3055-429: The health of the public and ensure the product quality is maintained. To make sure there is no cross-contamination between product runs of different drugs, various cleaning procedures are performed. TOC concentration levels are used to track the success of these cleaning validation procedures. Organic contamination comes from multiple sources throughout the semiconductor manufacturing process. Organic residues left on

3120-446: The incoming stream. Field tests were conducted for a period of 90-days and used laboratory conformance measurements once per day to compare with analyser output to demonstrate the instrument's overall accuracy when subjected to many simultaneously changing parameters as experienced in real-time monitoring conditions. Field test results can provide information regarding instrument design, operation and maintenance requirements which influence

3185-548: The influent of the Bayport facility in which TOC concentrations can range from 490 to 1020 mg/L with an average of 870 mg/L. GCWDA conducts approximately 102 TOC analyses in their laboratory per day at their Bayport treatment facility and use TOC measurements for process control and billing purposes. GCWDA plans to use online TOC analysers for process control, detecting influent slug loads from industries and to potentially use online TOC analysers to detect and monitor volatiles of

3250-469: The leftover carbon. This method involves purging an acidified sample with carbon-free air or nitrogen prior to measurement, and so is more accurately called non-purgeable organic carbon (NPOC). Since all TOC analyzers only actually measure total carbon, TOC analysis always requires some accounting for the inorganic carbon that is always present. One analysis technique involves a two-stage process commonly referred to as TOC differential method. It measures

3315-428: The manufacturing industry has developed several concepts, such as matrix separation, ceramic reactors, better process control or methods without catalysts. In this oxidation scheme, ultraviolet light alone oxidizes the carbon within the sample to produce CO 2 . The UV oxidation method offers the most reliable, low maintenance method of analyzing TOC in ultra-pure waters. Like the photo-oxidation method, UV light

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3380-423: The most important unconventional fuels. Numerous evaluation methods have been introduced, including these based on wireline logs and in situ techniques. Introduction of organic matter into water systems occurs not only from living organisms and from decaying matter in source water, but also from purification and distribution system materials. A relationship may exist between endotoxins , microbial growth, and

3445-418: The most vital components of the TOC analysis process. Conductivity and non-dispersive infrared (NDIR) are the two common detection methods used in modern TOC analyzers. There are two types of conductivity detectors, direct and membrane. Direct conductivity provides an all-encompassing approach of measuring CO 2 . This detection method uses no carrier gas, is good at the parts per billion (ppb) ranges, but has

3510-431: The neck is bent in the horizontal plane, drawing the head into a space in front of one of the front legs. A larger overhang of the carapace helps to protect the neck, which remains partially exposed after retraction. This differs from the method employed by a cryptodiran , which tucks its head and neck between its forelegs, within the shell. The different methods of bending the neck require completely different anatomies of

3575-466: The overlying Romualdo Formation by regional unconformities in proximal domains. The lower unconformity separates the top of the Crato Formation, which is mainly represented by its uppermost interval of laminated limestones (C6), from the basal black shales and claystone deposits of the Ipubi Formation. These basal deposits formed due to the transgressive event that expanded the relative lake level beyond

3640-415: The performance of the instruments in field applications. The field test report includes evaluations of online TOC analysers utilizing the following technologies: High temperature combustion (HTC), high temperature catalytic/combustion oxidation (HTCO), supercritical water oxidation (SCWO), and two-stage advanced oxidation (TSAO). In a combustion analyser, half of the sample is injected into a chamber where it

3705-471: The previous extension of the Crato Formation over the adjacent basement areas. During the Ipubi transgression, anoxic conditions influenced the formation of basal black shales with high levels of TOC . The carbonaceous pyrobitumen shales of the Ipubi Formation occur as a 0.5 to 2 metres (1.6 to 6.6 ft) layer in most of the mines in the region and have a potential for shale gas development. The deposition of

3770-477: The pterygoid. One of the three extant families in this suborder is the family Chelidae , which have a specially adapted strategy for catching prey. While the majority of the family Chelidae are omnivores, 17 species are carnivorous: Chelus fimbriatus and species of the Chelodina genus. This special strategy is referred to as a gape-suck mechanism. The turtle first opens its mouth little by little. Then, when

3835-430: The remaining non-purgeable organic carbon (NPOC). This is called TIC-NPOC analysis. TC oxidizes in a combustion chamber at 1000 degrees Celsius; if no supporting catalyst is used to allow full combustion at temperatures lower than 1000 degrees C; while the combustion chamber for IC heats only to 150 degrees Celsius. The reason for this is because inorganic is decomposed at lower temperatures than organic carbons. Whether

3900-473: The sample aliquot. A new advance of NDIR technology is static pressurized concentration (SPC). The exit valve of the NDIR is closed to allow the detector to become pressurized. Once the gases in the detector have reached equilibrium , the concentration of the CO 2 is analyzed. This pressurization of the sample gas stream in the NDIR, a patented technique, allows for increased sensitivity and precision by measuring

3965-419: The sample onto a catalyst in a combustion tube operated from 680 up to 950 degrees C in an oxygen rich atmosphere. The concentration of carbon dioxide generated is measured with a non-dispersive infrared (NDIR) detector. Oxidation of the sample is complete after injection into the furnace, turning oxidizable material in the sample into gaseous form . A carbon-free carrier gas transports the CO 2 , through

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4030-477: The skull. Another difference is in the arrangement of the bones of the shell and the scutes overlaying them. Pleurodiran turtles have 13 scutes on the plastron of the shell, whereas cryptodiran turtles have only 12. The extra scute is called the intergular and is at the front of the plastron between the gular scutes . Pelomedusid turtles also possess mesoplastra , further differentiating this group. The jaw closure mechanism has articulation on trochlear surfaces of

4095-491: The trace limits of DBPs in drinking water. Recently published analytical methods, such as United States Environmental Protection Agency (EPA) method 415.3, support the Agency's Disinfectants and Disinfection Byproducts Rules, which regulate the amount of NOM to prevent the formation of DBPs in finished waters. The content of TOC is also an important parameter to evaluate the quality of organic shale resources which are one of

4160-526: The turtle is within striking range of the prey, it will open its mouth completely, sucking in water at such a rate that the current into its mouth is too strong for prey to escape and it engulfs the prey within 0.004 seconds. This strategy also circumvents issues to quick capture of underwater prey, such as resistance to rapid movement in water, pressure waves due to a rapid strike, and rapid water intake when feeding. After Ferreria, et al. 2018. Total Organic Carbon Total organic carbon ( TOC )

4225-467: The two living suborders of turtles , the other being the Cryptodira . The division between these two suborders represents a very deep evolutionary divide between two very different types of turtles. The physical differences between them, although anatomical and largely internal, are nonetheless significant, and the zoogeographic implications of them are substantial. The Pleurodira are known more commonly as

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