PeerJ:Ecohydrologyhttps://peerj.com/articles/index.atom?journal=peerj&subject=1427Ecohydrology articles published in PeerJDomestic sewage dispersion scenarios as a subsidy to the design of urban sewage systems in the Lower Amazon River, Amapá, Brazilhttps://peerj.com/articles/169332024-02-272024-02-27Carlos Henrique Medeiros de AbreuElizandra Perez AraújoHelenilza Ferreira Albuquerque CunhaMarcelo TeixeiraAlan Cavalcanti da Cunha
The final in natura discharge of urban domestic sewage in rivers in the Amazon is a widespread practice. In addition, there is an evident lack of knowledge about the self-depurative characteristics of the receiving water bodies in these rivers. This problem is a challenge for designing sanitary sewage system (SSS) projects in the region. We aimed to numerically simulate hydrodynamic scenarios to study pollutant dispersion processes in an urban stretch impacted by domestic sewage in the Lower Amazon River (Amapá, Brazil) using a hydrodynamic model calibrated and coupled to a dispersive model (Lagrangian) (SisBaHiA). The following methodological steps were performed: (a) bathymetric and liquid discharge experimental campaigns using acoustic techniques (acoustic doppler current profiler—ADCP); (b) identification of point and diffuse sources of pollution in the Santana Channel (CSA) and North Channel of the Amazon River (NCM) in Macapá; (c) calibration of the hydrodynamic model and simulation of the dispersive process of domestic sewage plumes; (d) simulation of dispersive process scenarios in two seasonal hydrological periods and different tidal phases. The results of the simulations indicated significant spatiotemporal variations in the plumes, suggesting critical restriction of water quality in the dry period. The hotspot water collection supply station for ETA-CAESA was found to be the most threatened site by diffuse and point source loads. The simulated impacts showed that concentration variation worsens seasonally, restricting the multiple uses of water in both seasonal periods, regardless of tide phase. The pollutant plumes near the coastal-urban zone were apparently more inhibited by the influence of currents, and, due to the greater dilution capacity in the center of the channel, by the effect reversing with the approximation to the riverbank. The research hypotheses were supported: (a) the process of self-depuration of pollutants in the NCM has considerable limitations in shallow areas, and (b) SSS design projects in the region of the Amazon estuarine complex require hydrodynamic and strict water quality assessment, especially when their hydrological-seasonal and bathymetric characteristics are significantly unfavorable to dispersive processes. Thus, a hydrodynamic analysis should be the primary criterion in designing any SSS projects in this stretch of the estuarine Amazon region.
The final in natura discharge of urban domestic sewage in rivers in the Amazon is a widespread practice. In addition, there is an evident lack of knowledge about the self-depurative characteristics of the receiving water bodies in these rivers. This problem is a challenge for designing sanitary sewage system (SSS) projects in the region. We aimed to numerically simulate hydrodynamic scenarios to study pollutant dispersion processes in an urban stretch impacted by domestic sewage in the Lower Amazon River (Amapá, Brazil) using a hydrodynamic model calibrated and coupled to a dispersive model (Lagrangian) (SisBaHiA). The following methodological steps were performed: (a) bathymetric and liquid discharge experimental campaigns using acoustic techniques (acoustic doppler current profiler—ADCP); (b) identification of point and diffuse sources of pollution in the Santana Channel (CSA) and North Channel of the Amazon River (NCM) in Macapá; (c) calibration of the hydrodynamic model and simulation of the dispersive process of domestic sewage plumes; (d) simulation of dispersive process scenarios in two seasonal hydrological periods and different tidal phases. The results of the simulations indicated significant spatiotemporal variations in the plumes, suggesting critical restriction of water quality in the dry period. The hotspot water collection supply station for ETA-CAESA was found to be the most threatened site by diffuse and point source loads. The simulated impacts showed that concentration variation worsens seasonally, restricting the multiple uses of water in both seasonal periods, regardless of tide phase. The pollutant plumes near the coastal-urban zone were apparently more inhibited by the influence of currents, and, due to the greater dilution capacity in the center of the channel, by the effect reversing with the approximation to the riverbank. The research hypotheses were supported: (a) the process of self-depuration of pollutants in the NCM has considerable limitations in shallow areas, and (b) SSS design projects in the region of the Amazon estuarine complex require hydrodynamic and strict water quality assessment, especially when their hydrological-seasonal and bathymetric characteristics are significantly unfavorable to dispersive processes. Thus, a hydrodynamic analysis should be the primary criterion in designing any SSS projects in this stretch of the estuarine Amazon region.Using vulnerability assessment to characterize coastal protection benefits provided by estuarine habitats of a dynamic intracoastal waterwayhttps://peerj.com/articles/167382024-02-192024-02-19Gregory M. VerutesPhilip F. YangScott F. EastmanCheryl L. DoughtyTherese E. AdgieKaitlyn DietzNicole G. DixAllix NorthGregory GuannelSamantha K. Chapman
The existence of coastal ecosystems depends on their ability to gain sediment and keep pace with sea level rise. Similar to other coastal areas, Northeast Florida (United States) is experiencing rapid population growth, climate change, and shifting wetland communities. Rising seas and more severe storms, coupled with the intensification of human activities, can modify the biophysical environment, thereby increasing coastal exposure to storm-induced erosion and inundation. Using the Guana Tolomato Matanzas National Estuarine Research Reserve as a case study, we analyzed the distribution of coastal protection services–expressly, wave attenuation and sediment control–provided by estuarine habitats inside a dynamic Intracoastal waterway. We explored six coastal variables that contribute to coastal flooding and erosion–(a) relief, (b) geomorphology, (c) estuarine habitats, (d) wind exposure, (e) boat wake energy, and (f) storm surge potential–to assess physical exposure to coastal hazards. The highest levels of coastal exposure were found in the north and south sections of the Reserve (9% and 14%, respectively) compared to only 4% in the central, with exposure in the south driven by low wetland elevation, high surge potential, and shorelines composed of less stable sandy and muddy substrate. The most vulnerable areas of the central Reserve and main channel of the Intracoastal waterway were exposed to boat wakes from larger vessels frequently traveling at medium speeds (10–20 knots) and had shoreline segments oriented towards the prevailing winds (north-northeast). To guide management for the recently expanded Reserve into vulnerable areas near the City of Saint Augustine, we evaluated six sites of concern where the current distribution of estuarine habitats (mangroves, salt marshes, and oyster beds) likely play the greatest role in natural protection. Spatially explicit outputs also identified potential elevation maintenance strategies such as living shorelines, landform modification, and mangrove establishment for providing coastal risk-reduction and other ecosystem-service co-benefits. Salt marshes and mangroves in two sites of the central section (N-312 and S-312) were found to protect more than a one-quarter of their cross-shore length (27% and 73%, respectively) from transitioning to the highest exposure category. Proposed interventions for mangrove establishment and living shorelines could help maintain elevation in these sites of concern. This work sets the stage for additional research, education, and outreach about where mangroves, salt marshes, and oyster beds are most likely to reduce risk to wetland communities in the region.
The existence of coastal ecosystems depends on their ability to gain sediment and keep pace with sea level rise. Similar to other coastal areas, Northeast Florida (United States) is experiencing rapid population growth, climate change, and shifting wetland communities. Rising seas and more severe storms, coupled with the intensification of human activities, can modify the biophysical environment, thereby increasing coastal exposure to storm-induced erosion and inundation. Using the Guana Tolomato Matanzas National Estuarine Research Reserve as a case study, we analyzed the distribution of coastal protection services–expressly, wave attenuation and sediment control–provided by estuarine habitats inside a dynamic Intracoastal waterway. We explored six coastal variables that contribute to coastal flooding and erosion–(a) relief, (b) geomorphology, (c) estuarine habitats, (d) wind exposure, (e) boat wake energy, and (f) storm surge potential–to assess physical exposure to coastal hazards. The highest levels of coastal exposure were found in the north and south sections of the Reserve (9% and 14%, respectively) compared to only 4% in the central, with exposure in the south driven by low wetland elevation, high surge potential, and shorelines composed of less stable sandy and muddy substrate. The most vulnerable areas of the central Reserve and main channel of the Intracoastal waterway were exposed to boat wakes from larger vessels frequently traveling at medium speeds (10–20 knots) and had shoreline segments oriented towards the prevailing winds (north-northeast). To guide management for the recently expanded Reserve into vulnerable areas near the City of Saint Augustine, we evaluated six sites of concern where the current distribution of estuarine habitats (mangroves, salt marshes, and oyster beds) likely play the greatest role in natural protection. Spatially explicit outputs also identified potential elevation maintenance strategies such as living shorelines, landform modification, and mangrove establishment for providing coastal risk-reduction and other ecosystem-service co-benefits. Salt marshes and mangroves in two sites of the central section (N-312 and S-312) were found to protect more than a one-quarter of their cross-shore length (27% and 73%, respectively) from transitioning to the highest exposure category. Proposed interventions for mangrove establishment and living shorelines could help maintain elevation in these sites of concern. This work sets the stage for additional research, education, and outreach about where mangroves, salt marshes, and oyster beds are most likely to reduce risk to wetland communities in the region.Effects of restoration years on soil nitrogen and phosphorus in inland salt marsheshttps://peerj.com/articles/167662024-01-162024-01-16Dandan ZhaoDaiji WanJian YangJiping LiuZhicheng YongChongya Ma
Inland salt marsh wetlands have very important ecological functions in semi-arid areas. However, degradation and soil desertification have impacted these areas, making it necessary to study the impact of wetland restoration years on the soil quality of salt marsh wetland. We used remote sensing methods, field surveys, and inquiries to examine the seasonal profile effects of two-, four-, and six-year restoration periods on total nitrogen (TN), total phosphorus (TP) and the ratio of nitrogen to phosphorus (N:P) in P. australis and S. triqueter wetland natural states. Our results showed that soil TN in P. australis wetland in restored conditions was higher than that in natural conditions. The average soil TP of the S. triqueter wetlands at 0–10 cm, 10–20 cm, 20–30 cm, and 30–40 cm layers was 0.36 g/kg, 0.31 g/kg, 0.21 g/kg, and 0.17 g/kg s in September, respectively. The soil TP of the S. triqueter wetland increased slightly over the entire growing season. The restoration years had a great influence on the soil TP of the S. triqueter wetland from May to July. The soil TN in the P. australis wetland was almost restored to its natural condition in each layer during the six-year restoration period. The soil TP of the S. triqueter wetland was higher in the restored two-year period and showed a decreasing trend with an increased soil depth. Our conclusions can significantly guide the restoration of inland salt marsh wetlands.
Inland salt marsh wetlands have very important ecological functions in semi-arid areas. However, degradation and soil desertification have impacted these areas, making it necessary to study the impact of wetland restoration years on the soil quality of salt marsh wetland. We used remote sensing methods, field surveys, and inquiries to examine the seasonal profile effects of two-, four-, and six-year restoration periods on total nitrogen (TN), total phosphorus (TP) and the ratio of nitrogen to phosphorus (N:P) in P. australis and S. triqueter wetland natural states. Our results showed that soil TN in P. australis wetland in restored conditions was higher than that in natural conditions. The average soil TP of the S. triqueter wetlands at 0–10 cm, 10–20 cm, 20–30 cm, and 30–40 cm layers was 0.36 g/kg, 0.31 g/kg, 0.21 g/kg, and 0.17 g/kg s in September, respectively. The soil TP of the S. triqueter wetland increased slightly over the entire growing season. The restoration years had a great influence on the soil TP of the S. triqueter wetland from May to July. The soil TN in the P. australis wetland was almost restored to its natural condition in each layer during the six-year restoration period. The soil TP of the S. triqueter wetland was higher in the restored two-year period and showed a decreasing trend with an increased soil depth. Our conclusions can significantly guide the restoration of inland salt marsh wetlands.Temperature vegetation dryness index (TVDI) for drought monitoring in the Guangdong Province from 2000 to 2019https://peerj.com/articles/163372023-12-182023-12-18Ailin ChenJiajun JiangYong LuoGuoqi ZhangBin HuXiao WangShiqi Zhang
Drought monitoring is crucial for assessing and mitigating the impacts of water scarcity on various sectors and ecosystems. Although traditional drought monitoring relies on soil moisture data, remote sensing technology has have significantly augmented the capabilities for drought monitoring. This study aims to evaluate the accuracy and applicability of two temperature vegetation drought indices (TVDI), TVDINDVI and TVDIEVI, constructed using the Normalized Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI) vegetation indices for drought monitoring. Using Guangdong Province as a case, enhanced versions of these indices, developed through Savitzky–Golay filtering and terrain correction were employed. Additionally, Pearson correlation analysis and F-tests were utilized to determine the suitability of the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI) in correlation with TVDINDVI and TVDIEVI. The results show that TVDINDVI had more meteorological stations passing both significance test levels (P < 0.001 and P < 0.05) compared to TVDIEVI, and the average Pearson’R correlation coefficient was slightly higher than that of TVDIEVI, indicating that TVDINDVI responded better to drought in Guangdong Province. Our conclusion reveals that drought-prone regions in Guangdong Province are concentrated in the Leizhou Peninsula in southern Guangdong and the Pearl River Delta in central Guangdong. We also analyzed the phenomenon of winter-spring drought in Guangdong Province over the past 20 years. The area coverage of different drought levels was as follows: mild drought accounted for 42% to 64.6%, moderate drought accounted for 6.96% to 27.92%, and severe drought accounted for 0.002% to 1.84%. In 2003, the winter-spring drought in the entire province was the most severe, with a drought coverage rate of up to 84.2%, while in 2009, the drought area coverage was the lowest, at 49.02%. This study offers valuable insights the applicability of TVDI, and presents a viable methodology for drought monitoring in Guangdong Province, underlining its significance to agriculture, environmental conservation, and socio-economic facets in the region.
Drought monitoring is crucial for assessing and mitigating the impacts of water scarcity on various sectors and ecosystems. Although traditional drought monitoring relies on soil moisture data, remote sensing technology has have significantly augmented the capabilities for drought monitoring. This study aims to evaluate the accuracy and applicability of two temperature vegetation drought indices (TVDI), TVDINDVI and TVDIEVI, constructed using the Normalized Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI) vegetation indices for drought monitoring. Using Guangdong Province as a case, enhanced versions of these indices, developed through Savitzky–Golay filtering and terrain correction were employed. Additionally, Pearson correlation analysis and F-tests were utilized to determine the suitability of the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI) in correlation with TVDINDVI and TVDIEVI. The results show that TVDINDVI had more meteorological stations passing both significance test levels (P < 0.001 and P < 0.05) compared to TVDIEVI, and the average Pearson’R correlation coefficient was slightly higher than that of TVDIEVI, indicating that TVDINDVI responded better to drought in Guangdong Province. Our conclusion reveals that drought-prone regions in Guangdong Province are concentrated in the Leizhou Peninsula in southern Guangdong and the Pearl River Delta in central Guangdong. We also analyzed the phenomenon of winter-spring drought in Guangdong Province over the past 20 years. The area coverage of different drought levels was as follows: mild drought accounted for 42% to 64.6%, moderate drought accounted for 6.96% to 27.92%, and severe drought accounted for 0.002% to 1.84%. In 2003, the winter-spring drought in the entire province was the most severe, with a drought coverage rate of up to 84.2%, while in 2009, the drought area coverage was the lowest, at 49.02%. This study offers valuable insights the applicability of TVDI, and presents a viable methodology for drought monitoring in Guangdong Province, underlining its significance to agriculture, environmental conservation, and socio-economic facets in the region.Water-use characteristics of Syzygium antisepticum and Adinandra integerrima in a secondary forest of Khao Yai National Park in Thailand with implications for environmental managementhttps://peerj.com/articles/165252023-11-302023-11-30Ratchanon AmpornpitakAnuttara NathalangPantana Tor-ngern
Background
Southeast Asia has experienced widespread deforestation and change in land use. Consequently, many reforestation projects have been initiated in this region. However, it is imperative to carefully choose the tree species for planting, especially in light of the increasing climate variability and the potential alteration of plantation on the watershed water balance. Thus, the information regarding water-use characteristics of various tree species and sizes is critical in the tree species selection for reforestation.
Methods
We estimated tree water use (T) of dominant species including Syzygium antisepticum and Adinandra integerrima, hereafter Sa and Ai, respectively, in a secondary tropical forest in Khao Yai National Park, Thailand, using sap flow data, and compared T between species and size classes. Additionally, we evaluated the responses of T of both species in each size class to environmental factors including soil moisture and vapor pressure deficit (VPD).
Results
Results showed consistently higher T in Sa compared to Ai across ranges of VPD and soil moisture. Under low soil moisture, T of Sa responded to VPD, following a saturating exponential pattern while Ai maintained T across different VPD levels, irrespective of tree size. No responses of T to VPD were observed in either species when soil water was moderate. When soil moisture was high, T of both species significantly increased and saturated at high VPD, albeit the responses were less sensitive in large trees. Our results imply that Ai may be suitable for reforestation in water-limited areas where droughts frequently occur to minimize reforestation impact on water availability to downstream ecosystems. In contrast, Sa should be planted in regions with abundant and reliable water resources. However, a mixed species plantation should be generally considered to increase forest resilience to increasing climate variation.
Background
Southeast Asia has experienced widespread deforestation and change in land use. Consequently, many reforestation projects have been initiated in this region. However, it is imperative to carefully choose the tree species for planting, especially in light of the increasing climate variability and the potential alteration of plantation on the watershed water balance. Thus, the information regarding water-use characteristics of various tree species and sizes is critical in the tree species selection for reforestation.
Methods
We estimated tree water use (T) of dominant species including Syzygium antisepticum and Adinandra integerrima, hereafter Sa and Ai, respectively, in a secondary tropical forest in Khao Yai National Park, Thailand, using sap flow data, and compared T between species and size classes. Additionally, we evaluated the responses of T of both species in each size class to environmental factors including soil moisture and vapor pressure deficit (VPD).
Results
Results showed consistently higher T in Sa compared to Ai across ranges of VPD and soil moisture. Under low soil moisture, T of Sa responded to VPD, following a saturating exponential pattern while Ai maintained T across different VPD levels, irrespective of tree size. No responses of T to VPD were observed in either species when soil water was moderate. When soil moisture was high, T of both species significantly increased and saturated at high VPD, albeit the responses were less sensitive in large trees. Our results imply that Ai may be suitable for reforestation in water-limited areas where droughts frequently occur to minimize reforestation impact on water availability to downstream ecosystems. In contrast, Sa should be planted in regions with abundant and reliable water resources. However, a mixed species plantation should be generally considered to increase forest resilience to increasing climate variation.Diversity and ice nucleation activity of Pseudomonas syringae in drone-based water samples from eight lakes in Austriahttps://peerj.com/articles/163902023-11-282023-11-28Regina HanlonCelia Jimenez-SanchezJames BensonKen AhoCindy MorrisTeresa M. SeifriedPhilipp BalohHinrich GrotheDavid Schmale
Bacteria from the Pseudomonas syringae complex (comprised of at least 15 recognized species and more than 60 different pathovars of P. syringae sensu stricto) have been cultured from clouds, rain, snow, streams, rivers, and lakes. Some strains of P. syringae express an ice nucleation protein (hereafter referred to as ice+) that catalyzes the heterogeneous freezing of water. Though P. syringae has been sampled intensively from freshwater sources in the U.S. and France, little is known about the genetic diversity and ice nucleation activity of P. syringae in other parts of the world. We investigated the haplotype diversity and ice nucleation activity at −8 °C (ice+) of strains of P. syringae from water samples collected with drones in eight freshwater lakes in Austria. A phylogenetic analysis of citrate synthase (cts) sequences from 271 strains of bacteria isolated from a semi-selective medium for Pseudomonas revealed that 69% (188/271) belonged to the P. syringae complex and represented 32 haplotypes in phylogroups 1, 2, 7, 9, 10, 13, 14 and 15. Strains within the P. syringae complex were identified in all eight lakes, and seven lakes contained ice+ strains. Partial 16S rDNA sequences were analyzed from a total of 492 pure cultures of bacteria isolated from non-selective medium. Nearly half (43.5%; 214/492) were associated with the genus Pseudomonas. Five of the lakes (ALT, GRU, GOS, GOL, and WOR) were all distinguished by high levels of Pseudomanas (p ≤ 0.001). HIN, the highest elevation lake, had the highest percentage of ice+ strains. Our work highlights the potential for uncovering new haplotypes of P. syringae in aquatic habitats, and the use of robotic technologies to sample and characterize microbial life in remote settings.
Bacteria from the Pseudomonas syringae complex (comprised of at least 15 recognized species and more than 60 different pathovars of P. syringae sensu stricto) have been cultured from clouds, rain, snow, streams, rivers, and lakes. Some strains of P. syringae express an ice nucleation protein (hereafter referred to as ice+) that catalyzes the heterogeneous freezing of water. Though P. syringae has been sampled intensively from freshwater sources in the U.S. and France, little is known about the genetic diversity and ice nucleation activity of P. syringae in other parts of the world. We investigated the haplotype diversity and ice nucleation activity at −8 °C (ice+) of strains of P. syringae from water samples collected with drones in eight freshwater lakes in Austria. A phylogenetic analysis of citrate synthase (cts) sequences from 271 strains of bacteria isolated from a semi-selective medium for Pseudomonas revealed that 69% (188/271) belonged to the P. syringae complex and represented 32 haplotypes in phylogroups 1, 2, 7, 9, 10, 13, 14 and 15. Strains within the P. syringae complex were identified in all eight lakes, and seven lakes contained ice+ strains. Partial 16S rDNA sequences were analyzed from a total of 492 pure cultures of bacteria isolated from non-selective medium. Nearly half (43.5%; 214/492) were associated with the genus Pseudomonas. Five of the lakes (ALT, GRU, GOS, GOL, and WOR) were all distinguished by high levels of Pseudomanas (p ≤ 0.001). HIN, the highest elevation lake, had the highest percentage of ice+ strains. Our work highlights the potential for uncovering new haplotypes of P. syringae in aquatic habitats, and the use of robotic technologies to sample and characterize microbial life in remote settings.Confidence intervals for ratio of means of delta-lognormal distributions based on left-censored data with application to rainfall data in Thailandhttps://peerj.com/articles/163972023-11-092023-11-09Warisa ThangjaiSa-Aat Niwitpong
Thailand is a country that is prone to both floods and droughts, and these natural disasters have significant impacts on the country’s people, economy, and environment. Estimating rainfall is an important part of flood and drought prevention. Rainfall data typically contains both zero and positive observations, and the distribution of rainfall often follows the delta-lognormal distribution. However, it is important to note that rainfall data can be censored, meaning that some values may be missing or truncated. The interval estimator for the ratio of means will be useful when comparing the means of two samples. The purpose of this article was to compare the performance of several approaches for statistically analyzing left-censored data. The performance of the confidence intervals was evaluated using the coverage probability and average length, which were assessed through Monte Carlo simulation. The approaches examined included several variations of the generalized confidence interval, the Bayesian, the parametric bootstrap, and the method of variance estimates recovery approaches. For (ξ1, ξ2) = (0.10,0.10), simulations showed that the Bayesian approach would be a suitable choice for constructing the credible interval for the ratio of means of delta-lognormal distributions based on left-censored data. For (ξ1, ξ2) = (0.10,0.25), the parametric bootstrap approach was a strong alternative for constructing the confidence interval. However, the generalized confidence interval approach can be considered to construct the confidence when the sample sizes are increase. Practical applications demonstrating the use of these techniques on rainfall data showed that the confidence interval based on the generalized confidence interval approach covered the ratio of population means and had the smallest length. The proposed approaches’ effectiveness was illustrated using daily rainfall datasets from the provinces of Chiang Rai and Chiang Mai in Thailand.
Thailand is a country that is prone to both floods and droughts, and these natural disasters have significant impacts on the country’s people, economy, and environment. Estimating rainfall is an important part of flood and drought prevention. Rainfall data typically contains both zero and positive observations, and the distribution of rainfall often follows the delta-lognormal distribution. However, it is important to note that rainfall data can be censored, meaning that some values may be missing or truncated. The interval estimator for the ratio of means will be useful when comparing the means of two samples. The purpose of this article was to compare the performance of several approaches for statistically analyzing left-censored data. The performance of the confidence intervals was evaluated using the coverage probability and average length, which were assessed through Monte Carlo simulation. The approaches examined included several variations of the generalized confidence interval, the Bayesian, the parametric bootstrap, and the method of variance estimates recovery approaches. For (ξ1, ξ2) = (0.10,0.10), simulations showed that the Bayesian approach would be a suitable choice for constructing the credible interval for the ratio of means of delta-lognormal distributions based on left-censored data. For (ξ1, ξ2) = (0.10,0.25), the parametric bootstrap approach was a strong alternative for constructing the confidence interval. However, the generalized confidence interval approach can be considered to construct the confidence when the sample sizes are increase. Practical applications demonstrating the use of these techniques on rainfall data showed that the confidence interval based on the generalized confidence interval approach covered the ratio of population means and had the smallest length. The proposed approaches’ effectiveness was illustrated using daily rainfall datasets from the provinces of Chiang Rai and Chiang Mai in Thailand.Forecasting the flooding dynamics of flatwoods salamander breeding wetlands under future climate change scenarioshttps://peerj.com/articles/160502023-09-192023-09-19Houston C. ChandlerNicholas M. CarusoDaniel L. McLaughlinYan JiaoGeorge C. BrooksCarola A. Haas
Ephemeral wetlands are globally important systems that are regulated by regular cycles of wetting and drying, which are primarily controlled by responses to relatively short-term weather events (e.g., precipitation and evapotranspiration). Climate change is predicted to have significant effects on many ephemeral wetland systems and the organisms that depend on them through altered filling or drying dates that impact hydroperiod. To examine the potential effects of climate change on pine flatwoods wetlands in the southeastern United States, we created statistical models describing wetland hydrologic regime using an approximately 8-year history of water level monitoring and a variety of climate data inputs. We then assessed how hydrology may change in the future by projecting models forward (2025–2100) under six future climate scenarios (three climate models each with two emission scenarios). We used the model results to assess future breeding conditions for the imperiled Reticulated Flatwoods Salamander (Ambystoma bishopi), which breeds in many of the study wetlands. We found that models generally fit the data well and had good predictability across both training and testing data. Across all models and climate scenarios, there was substantial variation in the predicted suitability for flatwoods salamander reproduction. However, wetlands with longer hydroperiods tended to have fewer model iterations that predicted at least five consecutive years of reproductive failure (an important metric for population persistence). Understanding potential future risk to flatwoods salamander populations can be used to guide conservation and management actions for this imperiled species.
Ephemeral wetlands are globally important systems that are regulated by regular cycles of wetting and drying, which are primarily controlled by responses to relatively short-term weather events (e.g., precipitation and evapotranspiration). Climate change is predicted to have significant effects on many ephemeral wetland systems and the organisms that depend on them through altered filling or drying dates that impact hydroperiod. To examine the potential effects of climate change on pine flatwoods wetlands in the southeastern United States, we created statistical models describing wetland hydrologic regime using an approximately 8-year history of water level monitoring and a variety of climate data inputs. We then assessed how hydrology may change in the future by projecting models forward (2025–2100) under six future climate scenarios (three climate models each with two emission scenarios). We used the model results to assess future breeding conditions for the imperiled Reticulated Flatwoods Salamander (Ambystoma bishopi), which breeds in many of the study wetlands. We found that models generally fit the data well and had good predictability across both training and testing data. Across all models and climate scenarios, there was substantial variation in the predicted suitability for flatwoods salamander reproduction. However, wetlands with longer hydroperiods tended to have fewer model iterations that predicted at least five consecutive years of reproductive failure (an important metric for population persistence). Understanding potential future risk to flatwoods salamander populations can be used to guide conservation and management actions for this imperiled species.Developing bottom drifters to better understand the stranding locations of cold-stunned sea turtles in Cape Cod Bay, Massachusettshttps://peerj.com/articles/158662023-08-302023-08-30Felicia M. PageJames ManningLesley HowardRyan HealeyNancy E. Karraker
Every fall, juvenile sea turtles in the Northwest Atlantic Ocean are threatened by rapidly declining water temperatures. When sea turtles become hypothermic, or cold-stunned, they lose mobility—either at the surface, subsurface, or the bottom of the water column—and eventually strand at the shoreline where rescue teams associated with the Sea Turtle Stranding and Salvage Network may search for them. Understanding the effects of ocean currents on the potential stranding locations of cold-stunned sea turtles is essential to better understand stranding hotspots and increase the probability of successful discovery and recovery of turtles before they die in the cold temperatures. Traditional oceanographic drifters—instruments used to track currents—have been used to examine relationships between current and stranding locations in Cape Cod Bay, but these drifters are not representative of sea turtle morphology and do not assess how bottom currents affect stranding locations. To address these knowledge gaps, we designed new drifters that represent the shape and dimensions of sea turtles—one that can float at the surface and one that sinks to the bottom—to track both surface and bottom currents in Cape Cod Bay. We found a marked difference between the trajectories of our new drifter models and those that were previously used for similar research. These findings bring us one step closer to identifying the transport pathways for cold-stunned sea turtles and optimizing cold-stunned sea turtle search and rescue efforts in Cape Cod.
Every fall, juvenile sea turtles in the Northwest Atlantic Ocean are threatened by rapidly declining water temperatures. When sea turtles become hypothermic, or cold-stunned, they lose mobility—either at the surface, subsurface, or the bottom of the water column—and eventually strand at the shoreline where rescue teams associated with the Sea Turtle Stranding and Salvage Network may search for them. Understanding the effects of ocean currents on the potential stranding locations of cold-stunned sea turtles is essential to better understand stranding hotspots and increase the probability of successful discovery and recovery of turtles before they die in the cold temperatures. Traditional oceanographic drifters—instruments used to track currents—have been used to examine relationships between current and stranding locations in Cape Cod Bay, but these drifters are not representative of sea turtle morphology and do not assess how bottom currents affect stranding locations. To address these knowledge gaps, we designed new drifters that represent the shape and dimensions of sea turtles—one that can float at the surface and one that sinks to the bottom—to track both surface and bottom currents in Cape Cod Bay. We found a marked difference between the trajectories of our new drifter models and those that were previously used for similar research. These findings bring us one step closer to identifying the transport pathways for cold-stunned sea turtles and optimizing cold-stunned sea turtle search and rescue efforts in Cape Cod.A method of constructing a dynamic chart depth model for coastal areashttps://peerj.com/articles/156162023-07-202023-07-20Minglei GuanChenyang TianBin WangFangzheng JiRui SunSong YuChongping WangQi WangJingzhe WangWei ZhangDejin Zhang
The depth is important for vessel navigation at sea. Currently, most vessels use electronic navigation charts to navigate at sea. In coastal areas, especially close to shallow water areas, the dynamic change of the water level is very important to safe navigation. Ships calculate the change of water level by using up-to-date tide tables, to obtain the dynamic water depth in the channels. However, the depth caused by the tide and non-tidal components may reach several meters in some seas, causing the dynamic depth below the safety depth, which can easily lead to grounding of vessels stranding accidents. The channel is regularly dredged to achieve navigational depth. Without regular dredging, the offshore non-channel area becomes the common area of ship grounding. The dynamic chart depth model studied in this article can provide real-time depth, which serves the ships navigation in the non-channel. The model incorporates the chart depth and the dynamic water levels on the same reference datum. The chart depth is from the electronic navigational chart depth. The dynamic water levels are constructed by the simulated tidal levels and continuous series of nontidal residual. We then designed a deviation correction method to reduce the discrepancy of the simulated tidal level with the actual water level, including datum offset correction and residual water level correction. Finally, by merging the revised dynamic water levels with the electronic navigational chart depth, we obtained the dynamic chart depth model of the study region.
The depth is important for vessel navigation at sea. Currently, most vessels use electronic navigation charts to navigate at sea. In coastal areas, especially close to shallow water areas, the dynamic change of the water level is very important to safe navigation. Ships calculate the change of water level by using up-to-date tide tables, to obtain the dynamic water depth in the channels. However, the depth caused by the tide and non-tidal components may reach several meters in some seas, causing the dynamic depth below the safety depth, which can easily lead to grounding of vessels stranding accidents. The channel is regularly dredged to achieve navigational depth. Without regular dredging, the offshore non-channel area becomes the common area of ship grounding. The dynamic chart depth model studied in this article can provide real-time depth, which serves the ships navigation in the non-channel. The model incorporates the chart depth and the dynamic water levels on the same reference datum. The chart depth is from the electronic navigational chart depth. The dynamic water levels are constructed by the simulated tidal levels and continuous series of nontidal residual. We then designed a deviation correction method to reduce the discrepancy of the simulated tidal level with the actual water level, including datum offset correction and residual water level correction. Finally, by merging the revised dynamic water levels with the electronic navigational chart depth, we obtained the dynamic chart depth model of the study region.