Water Conservation Area Research Articles

SIKAP MASYARAKAT NELAYAN KELURAHAN BONTANG BARU TERHADAP IMPLEMENTASI PROGRAM KAWASAN KONSERVASI PERAIRAN DI WILAYAH PESISIR DAN LAUT KOTA BONTANG

The purpose of this study were to determine the socio-economic characteristics, perception, motivation, and public attitudes towards regional coastal development program. Also to know the relationship between socioeconomic characteristic, perception and motivation with public attitudes of the Bontang Baru fisherman community toward the program implementation of water conservation area in Bontang City coral zone. Sampling method use census sampling with 54 respondents. The research has been conducted on Februari to Oktober 2017. Data analysis methods use descriptive qualitative method and quantitative analysis method with Rank Spearman’s correlation. The socioeconomic characteristics factors not related with attitudes of the Bontang Baru fisherman community toward the program implementation of water conservation area in Bontang City coral zone. The perception factor has realitionship to attitude on variabel of conseption conformity and the extention intensity toward the fisherman attitude. The motivation factor has realitionship to attitude on variabel the recognition of creadibility toward the attitudes of the Bontang Baru fisherman community toward the program implementation of water conservation area in Bontang City coral zone.

Research Analysis of temporal and spatial characteristics of eco-environmental vulnerability in the Xianshui River basin based on GIS

The Xianshui River basin is an important ecological barrier and water conservation area of Qinghai-Tibet plateau. To master the spatial and temporal differentiation of ecological environment is beneficial to the realization of the protection of regional ecological environment and the development of restoration measures. In this paper, the evaluation index system of ecological environment vulnerability was constructed from topography, climate, soil, land use and social economy. In this study, GIS and information entropy theory are combined to complete the analysis of spatial and temporal variation of vulnerability of ecological environment vulnerability in 2000-2015 years, and the main results are as follows: The ecological vulnerability of the watershed is characterized by the obvious vertical distribution, which is characterized by the gradual increase of the vulnerability of the south to the north. The evaluation results were classified as potential, micro, mild, moderate and severe, with the proportion of each grade being Micro > mild > potential > moderate > severity. The proportion of light and below accounts for more than 80% of the whole area, and the whole basin is at a medium vulnerable level. The change of overall trend indicates that the overall ecological environment of the basin has improved obviously in 15 years. The driving force factor analysis shows that the national environmental protection and restoration project is playing a significant role and plays a major driving role in the obvious improvement of the ecological environment in the basin area. However, there are still a few parts of the region that are deteriorating. This is mainly due to the special natural environment and over exploitation of hydropower resources.

English

The study aims to evaluate major challenges, opportunities and future prospects of bee keeping and honey production in three districts of Waghimra Zone (Abergell, Sekota and Gazgibala). To collect data, 332 respondents were selected using systematic random sampling from the three districts. Data were collected using semi-structured questionnaire, observation, keyinformant interveiw and focus group discussion. Data were analyzed using descriptative statistics and analysis of variance (ANOVA) using statistical package for social science (SPSS) version-20. The results of this study indicated that beekeeping is one of the most important income generating activities besides other agricultural activities. The major challenges identified were prevalence of pests and predators, recurrent drought, indiscriminate application of pesticides and herbicides, lack of bee forage associated with deforestation,  lack of credit service for the beekeeping sector, absconding and migration of bee colonies, high cost and limited availability of modern beekeeping equipment’s and accessories, shortage of water, and lack of skill in beekeeping management. It has been revealed that the opportunities for beekeeping in the study areas were the existence of abundance of honeybee colonies, availability of potential flowering plants, sources of water for bees, increasing market demand for beehive products, existence of soil and water conservation practice and area enclosure in the area, beekeepers' experience and indigenous knowledge and socio-economic value of honey. Thus, based on these findings, improving the awareness of the beekeepers through training and strong extension service, supplying cheap bee keeping inputs, capacitating to beekeepers to control the pests and predators are important to address the identified challenges and to improve the overall honey production in Waghimara Zone. Key words: Bee colony, beehives, beekeeping, challenges, honey production, opportunities. &nbsp

Using Cluster Analysis to Compartmentalize a Large Managed Wetland Based on Physical, Biological, and Climatic Geospatial Attributes.

Hierarchical and partitional cluster analyses were used to compartmentalize Water Conservation Area 1, a managed wetland within the Arthur R. Marshall Loxahatchee National Wildlife Refuge in southeast Florida, USA, based on physical, biological, and climatic geospatial attributes. Single, complete, average, and Ward's linkages were tested during the hierarchical cluster analyses, with average linkage providing the best results. In general, the partitional method, partitioning around medoids, found clusters that were more evenly sized and more spatially aggregated than those resulting from the hierarchical analyses. However, hierarchical analysis appeared to be better suited to identify outlier regions that were significantly different from other areas. The clusters identified by geospatial attributes were similar to clusters developed for the interior marsh in a separate study using water quality attributes, suggesting that similar factors have influenced variations in both the set of physical, biological, and climatic attributes selected in this study and water quality parameters. However, geospatial data allowed further subdivision of several interior marsh clusters identified from the water quality data, potentially indicating zones with important differences in function. Identification of these zones can be useful to managers and modelers by informing the distribution of monitoring equipment and personnel as well as delineating regions that may respond similarly to future changes in management or climate.

Methanogens Are Major Contributors to Nitrogen Fixation in Soils of the Florida Everglades.

The objective of this study was to investigate the interaction of the nitrogen (N) cycle with methane production in the Florida Everglades, a large freshwater wetland. This study provides an initial analysis of the distribution and expression of N-cycling genes in Water Conservation Area 2A (WCA-2A), a section of the marsh that underwent phosphorus (P) loading for many years due to runoff from upstream agricultural activities. The elevated P resulted in increased primary productivity and an N limitation in P-enriched areas. Results from quantitative real-time PCR (qPCR) analyses indicated that the N cycle in WCA-2A was dominated by nifH and nirK/S, with an increasing trend in copy numbers in P-impacted sites. Many nifH sequences (6 to 44% of the total) and nifH transcript sequences (2 to 49%) clustered with the methanogenic Euryarchaeota, in stark contrast to the proportion of core gene sequences representing Archaea (≤0.27% of SSU rRNA genes) for the WCA-2A microbiota. Notably, archaeal nifH gene transcripts were detected at all sites and comprised a significant proportion of total nifH transcripts obtained from the unimpacted site, indicating that methanogens are actively fixing N2 Laboratory incubations with soils taken from WCA-2A produced nifH transcripts with the production of methane from H2 plus CO2 and acetate as electron donors and carbon sources. Methanogenic N2 fixation is likely to be an important, although largely unrecognized, route through which fixed nitrogen enters the anoxic soils of the Everglades and may have significant relevance regarding methane production in wetlands.IMPORTANCE Wetlands are the most important natural sources of the greenhouse gas methane, and much of that methane emanates from (sub)tropical peatlands. Primary productivity in these peatlands is frequently limited by the availability of nitrogen or phosphorus; however, the response to nutrient limitations of microbial communities that control biogeochemical cycling critical to ecosystem function may be complex and may be associated with a range of processes, including methane production. We show that many, if not most, of the methanogens in the peatlands of the Florida Everglades possess the nifH gene and actively express it for N2 fixation coupled with methanogenesis. These findings indicate that archaeal N2 fixation would play crucial role in methane emissions and overall N cycle in subtropical wetlands suffering N limitation.

Identification and classification of critical soil and water conservation areas in the Muskingum River basin in Ohio

The Muskingum River basin (MRB) of Ohio is the fourth most polluted watershed in the United States. To address water quality issues in the MRB, it is important to identify critical source areas (CSAs) that contribute disproportionately to high amounts of nonpoint source pollution. The Soil and Water Assessment Tool (SWAT) was used to develop a hydrological model in the MRB to identify conditions that cause land to be classified as CSAs in the basin. The model was calibrated for 10 years (1995 to 2004) and validated for 6 years (2005 to 2010) for streamflow, total suspended solids (TSS), total nitrogen (TN), and total phosphorus (TP) on a monthly scale. The validated model was then used to locate CSAs and the contributing sources of high nutrient discharges at the subbasin level in the MRB. Performance of conservation practices including terraces, buffer strips, 10% reduction in commercial and manure fertilizer use, and conservation tillage practices in the cropland of the CSAs were examined for their effectiveness in reducing nutrient loads at subbasin and watershed scales. In the MRB, average annual (1995 to 2010) subbasin yield for TSS, TN, and TP ranged from 0.02 to 1.23 Mg ha−1 y−1, 0.82 to 17 kg ha−1 y−1, and 0.03 to 2.6 kg ha−1 y−1, respectively. The slope of the landscape combined with land use practices were found to influence the water quality in the region. The cropland that comprises 22% of the basin was found to generate 70%, 63%, and 71% of the TSS, TN, and TP, respectively. Two percent of the cropland that is in steep landscape (>10% slope) was found to contribute to 29%, 6%, and 22% of the TSS, TN, and TP loads. While pasture land was found to generate 18% TSS, 15% TN, and 15% TP loads in the entire basin, these loadings were found to be significantly higher (53% TSS, 32% TN, and 64% TP) in the subbasins with intensive grazing activities. Evaluation of five conservation practices in the MRB suggested that terraces, vegetative filter strips, and controlled manure application are the most effective conservation practices to mitigate water quality issues in steep agricultural landscapes with complex management practices. The use of terraces was found to reduce the TSS (4% to 44%), TN (4% to 26%), and TP (5% to 53%) loads. Similarly, TSS, TN, and TP loads were reduced by 4% to 45%, 5% to 28%, and 7% to 45%, respectively, with filter strips practice in the basin. Nevertheless, none of the conservation practices in the cropland helped reduce sediment and nutrient loads by more than 12% in the outlet of the basin, suggesting that the conservation practices should be expanded to other land uses of the basin.

Carbon pool trends and dynamics within a subtropical peatland during long-term restoration

IntroductionThe Florida Everglades has undergone significant ecological change spanning the continuum of disturbance to restoration. While the restoration effort is not complete and the ecosystem continues to experience short duration perturbations, a better understanding of long-term C dynamics of the Everglades is needed to facilitate new restoration efforts. This study evaluated temporal trends of different aquatic carbon (C) pools of the northern Everglades Protection Area over a 20-year period to gauge historic C cycling patterns. Dissolved inorganic C (DIC), dissolved organic C (DOC), particulate organic C (POC), and surface water carbon dioxide (pCO2(aq)) were investigated between May 1, 1994 and April 30, 2015.ResultsAnnual mean concentrations of DIC, DOC, POC, and pCO2(aq) significantly decreased through time or remained constant across the Water Conservation Areas (WCAs). Overall, the magnitude of the different C pools in the water column significantly differed between regions. Outgassing of CO2 was dynamic across the Everglades ranging from 420 to 2001 kg CO2 year−1. Overall, the historic trend in CO2 flux from the marsh declined across our study area while pCO2(aq) largely remained somewhat constant with the exception of Water Conservation Area 2 which experienced significant declines in pCO2(aq). Particulate OC concentrations were consistent between WCAs, but a significantly decreasing trend in annual POC concentrations was observed.ConclusionsHydrologic condition and nutrient inputs significantly influenced the balance, speciation, and flux of C pools across WCAs suggesting a subsidy-stress response in C dynamics relative to landscape scale responses in nutrient availability. The interplay between nutrient inputs and hydrologic condition exert a driving force on the balance between DIC and DOC production via the metabolism of organic matter which forms the base of the aquatic food web. Along the restoration trajectory as water quality and hydrology continues to improve, it is expected that C pools will respond accordingly.

SPATIAL ANALYSIS IDENTIFICATION OF IDEAL AREAS CONSERVATION LOCATION IN TUAL CITY, MALUKU PROVINCE


 Tual City is the one of eleven districts / cities in Maluku Province. The city includes an archipelago town, has 66 islands divided into 3 island clusters, covering the cluster of Kur islands, Tayando Tam and Dullah. The sea area reaches 19,088 Km2, while the land area is 254.39 km2. The size of the sea in this area indicates the high utilization potential of both fisheries and tourism sector. Based on these, needed resources management the coastal and marine resources effectively, one of them by developing conservation area in coastal area and small islands. Tual City took the initiative to allocate part of its area to be reserved as a marine conservation area. The target of the formation of urban water conservation area Tual is the protection of important marine habitats consisting of coral reefs, seagrass and mangrove, sea turtle nesting beaches and connectivity larvae. This study was conducted to obtain potential locations of marine conservation areas that have high conservation value. Analysis of spatial data using Marxan analysis. This analysis was chosen because it provides the best solution for determining locations that have high conservation value. The results of the study indicate that the area of selected high frequency locations is 125,000 hectares, while 40,000 hectares and 64,000 hectares low. Selected high-frequency locations are in the cluster of Kur islands, Tayando Tam and in the waters north of Mas Island and Bair. Based on this study, the cluster of Kur and Tayando Tam islands become the recommended sites requiring the management of marine conservation areas as they are representative of all conservation targets.
 
 
 Keywords
 Marine Protected Area, Marxan, and Tual City

Phosphorus concentrations in a Florida Everglades water conservation area before and after El Niño events in the dry season

The Florida Everglades depends on both seasonal hydroperiods and low nutrient loading. This study investigated phosphorus concentrations in a 237,000-ha wetland complex in the Greater Florida Everglades known as Water Conservation Area 3A (WCA-3A). WCA-3A is south and downstream of Lake Okeechobee and most of the agricultural activity in the Everglades region, but immediately north and upstream of the Everglades National Park. The original goal of the study was to investigate if this water conservation area was serving as a phosphorus sink during a 9-month period (October 2015 to June 2016) that normally would have bracketed the dry winter season of south Florida. The beginning of 2016 brought several unexpected polar fronts with high rainfall, an unusual weather pattern in subtropical Florida later confirmed to have been caused by an El Niño condition in the Pacific Ocean. Samples taken at the beginning of the dry season (October through December 2015 during pre-El Niño conditions) showed low phosphorus concentrations. In April and June 2016 during post-El Niño conditions, monthly average total phosphorus concentrations averaged 7.1–7.2ppb total phosphorus in inflow region of WCA-3A, significantly higher (P=0.030 and 0.045) than 3.0 and to 2.6ppb in the wetland’s outflow region. The wetland was found to be a sink of phosphorus with a 47% decrease in total phosphorus from north to south during this post- El Niño time. If future additional wetlands and water quality strategies are not in place to mitigate fluxes of phosphorus during future climate variations such as this El Niño condition, this wetland complex may take on an even greater role of protecting the water quality of the downstream Everglades National Park.

Historical record of nutrients inputs into the Xin’an Reservoir and its potential environmental implication

The Xin'an Reservoir is an important water supply source and water conservation area for the Qiantang River. However, after the occurrence of the two algae blooms in 1998 and 1999, the safety of water quality has been put into question. In order to study the historical deposition of nutrients, sediment cores were collected in different regions from the Xin'an Reservoir. The stable isotopes δ13C and δ15N, nutrients, total organic carbon (TOC), and inorganic carbon (IC) in the sediment cores were determined. Radiometric methods (210Pb and 137Cs) were used to obtain sediment chronologies. Spatially, it was found that the average total nitrogen (TN) content in the upper 5cm of sediments increased from 0.21% in the riverine zone, to 0.33%, and then to 0.57% in the lacustrine zone. The average TP content in the upper 5cm increased from 0.67gkg-1 in the riverine zone, to 1.03gkg-1 in the estuary region, and then to 1.65gkg-1 in the lacustrine zone. In addition, TOC levels showed a distinct increase from 1.42% in the bottom to 5.97% in the surface of the lacustrine zone. These results demonstrated that although primary productivity and the input of nutrients constantly increased in recent years, algae blooms rarely occurred in the Xin'an Reservoir, due to "depth effect" and an aquatic environment protection-oriented fishery policy. However, high TOC flux and high bio-available phosphorus and nitrogen in surface sediment demonstrated that the reservoir is still confronted with the potential risk of algae blooms.

Prediction of Groundwater Quality Trends Resulting from Anthropogenic Changes in Southeast Florida.

The effects of surface water flow system changes caused by constructing water-conservation areas and canals in southeast Florida on groundwater quality under the Atlantic Coastal Ridge was investigated with numerical modeling. Water quality data were used to delineate a zone of groundwater with low total dissolved solids (TDS) within the Biscayne aquifer under the ridge. The delineated zone has the following characteristics. Its location generally coincides with an area where the Biscayne aquifer has high transmissivities, corresponds to a high recharge area of the ridge, and underlies a part of the groundwater mound formed under the ridge prior to completion of the canals. This low TDS groundwater appears to be the result of pre-development conditions rather than seepage from the canals constructed after the 1950s. Numerical simulation results indicate that the time for low TDS groundwater under the ridge to reach equilibrium with high TDS surface water in the water-conservation areas and Everglades National Park are approximately 70 and 60 years, respectively. The high TDS groundwater would be restricted to the water-conservation areas and the park due to its slow eastward movement caused by small hydraulic gradients in Rocky Glades and its mixing with the low TDS groundwater under the high-recharge area of the ridge. The flow or physical boundary conditions such as high recharge rates or low hydraulic conductivity layers may affect how the spatial distribution of groundwater quality in an aquifer will change when a groundwater flow system reaches equilibrium with an associated surface water flow system.

Applying time series Landsat data for vegetation change analysis in the Florida Everglades Water Conservation Area 2A during 1996–2016

Mapping plant communities and documenting their changes is critical to the on-going Florida Everglades restoration project. In this study, a framework was designed to map dominant vegetation communities and inventory their changes in the Florida Everglades Water Conservation Area 2A (WCA-2A) using time series Landsat images spanning 1996–2016. The object-based change analysis technique was combined in the framework. A hybrid pixel/object-based change detection approach was developed to effectively collect training samples for historical images with sparse reference data. An object-based quantification approach was also developed to assess the expansion/reduction of a specific class such as cattail (an invasive species in the Everglades) from the object-based classifications of two dates of imagery. The study confirmed the results in the literature that cattail was largely expanded during 1996–2007. It also revealed that cattail expansion was constrained after 2007. Application of time series Landsat data is valuable to document vegetation changes for the WCA-2A impoundment. The digital techniques developed will benefit global wetland mapping and change analysis in general, and the Florida Everglades WCA-2A in particular.

Soil and water conservation in India: Strategies and research challenges

Soil and water are the most important natural resources that meet all human needs, and protect the environment and the civilization. Ever increasing demands for land and water resources due to burgeoning population cause the degradation of these two precious natural resources. Land degradation is a serious problem in India and out of 329 million hectare (Mha) of total geographical area, 146.8 Mha is reported as degraded. India is losing a huge amount of money in terms of loss of productivity from these degraded lands. Though India receives good amount of annual rainfall (1190 mm), due to enhanced need for domestic, agriculture and industrial developmental activities, over-exploitation and laxity of water resource, it becomes scarce. The declining trend of groundwater level in all parts of the country also indicates that the assured supply of good quality water will become a concern for country's development. Hence holistic management approach of soil and water resources by linking social and economic development with protection of natural ecosystem is the need of the hour. Creation of inventory on soil and water resources, use of modern technological tools for developing conservation strategies, changes in policy to protect natural resources, development of site specific soil and water conservation measures and involvement of local people in conserving the soil and water resources are the future challenges for the scientists and policy makers. This paper highlights the soil and water conservation strategies and areas to be addressed on priority.

基于RS和GIS的玛曲高原土地沙漠化时空演变研究

PDF HTML阅读 XML下载 导出引用 引用提醒 基于RS和GIS的玛曲高原土地沙漠化时空演变研究 DOI: 10.5846/stxb201509111881 作者: 作者单位: 西北师范大学地理与环境科学学院,西北师范大学地理与环境科学学院,西北师范大学地理与环境科学学院,西北师范大学地理与环境科学学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41161036，41171018）；甘肃省自然科学基金项目（1010RJZA016）；西北师范大学青年教师科研能力提升计划（NWNU-LKON-10-34） Spatio-temporal change in desertification of the Maqu Plateau based on RS and GIS Author: Affiliation: College of Geography and Environment Science, Northwest Normal University,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:基于RS和GIS空间分析技术，以玛曲高原多期Landsat遥感数据为主要信息源，监测分析了1977-2014年玛曲高原沙漠化土地的时空演变规律。结果表明：近40年来玛曲高原的土地沙漠化经历了迅速发展-缓慢发展-急速逆转-缓慢逆转-快速逆转的变化过程。1977-1995年玛曲高原沙漠化处于快速扩张阶段，年均扩张速率为3.01%；1995-2014年沙漠化扩张趋势出现逆转，年均逆转速率为4.14%。沙漠化土地的发展和逆转区域主要分布在东北部欧拉秀玛乡和尼玛乡黄河沿岸、东南部采日玛乡和曼日玛乡沼泽区、西南部齐哈玛乡和中部阿万仓乡黄河支流两岸。玛曲高原沙漠化土地的发展和逆转过程并非逐级递增或递减，而是在15-20年内交替出现，不同等级沙漠化土地之间的转移也存在明显的跃变。从整体来看，玛曲高原土地沙漠化呈现逆转趋势，区域生态环境得到明显改善。 Abstract:The Maqu plateau, an important part of the Qinghai-Tibet plateau, is the main water conservation area in the upper reaches of the Yellow River. In recent years, under the influence of natural environmental and human activities, the ecologically sensitive Maqu plateau area has experienced environmental problems such as glacier retreat, permafrost degradation, aeolian desertification, and grassland degradation. The Maqu plateau is one of the largest pasture lands in Asia, with a rangeland area of 8.58×107hm2. In the past decade, the eco-environmental problems of the Qinghai-Tibetan plateau have received increasing attention owing to global warming and intensifying regional development. The aim of this study was to quantify the developmental processes in these region, as well as any changes in the spatial distribution of land desertification. We used remote sensing (RS) and geographic information system (GIS) technologies, and applied multi-temporal Landsat imagery to investigate the spatio-temporal development of land desertification in the Maqu Plateau during 1977-2014. The remote-sensing data used in this study include:Landsat multi-spectral scanner images from 1977; Thematic Mapper images from 1989, 1995, 2006, and 2014; and Enhanced Thematic Mapper images from 2001 and 2010. We mainly selected images recorded between June and October, because aeolian desertified lands are more easily recognized during this period of greater vegetation growth. Our results indicated that the area of desertified land in the Maqu plateau had experienced five main phases:rapid development, where the area of aeolian desertified land increased at a rate of 2004.6 hm2/a between 1977 and 1989; slow development, where it increased at a rate of 57 hm2/a between 1989 and 1995; rapid reverse, where it decreased at a rate of 3868 hm2/a between 1995 and 2006; slow reverse, where it decreased at a rate of 893.4 hm2/a between 2006 and 2010; and, fast reverse, where it decreased at a rate of 2129.3 hm2/a between 2010 and 2014. The area of desertified land expanded rapidly between 1977 and 1995, with an average growth rate of 3.01% per year. An obvious decrease in the area of desertified land was observed from 1995 to 2014, with an average reversal rate of 4.14% per year. The areas affected by the development and reversal of aeolian desertification were mainly distributed alongside the Yellow River, including near the Oulaxiuma and Nima villages of the northeastern region, the marshlands of the Cairuma and Manrima villages in the southeastern region, and the riversides of tributaries to the Yellow River near the Qihama and Awancang villages of the southwestern region. We found that the spatial distribution of aeolian desertification changed significantly over time, with fragmentation of the desertified land increasing rapidly between 1977 and 1995. Aeolian desertification in the Maqu Plateau has not been progressive, but instead, it has been an alternating process of development and reversal approximately every 15 to 20 years. There was an abrupt change in the desertification level of lands in different levels of the plateau. Overall, we found that the trend of aeolian desertification in the Maqu plateau had been reversed and the local environment had improved since 1995. 参考文献 相似文献 引证文献

Nitrification, Anammox and Denitrification along a Nutrient Gradient in the Florida Everglades

The Florida Everglade wetland had been historically oligotrophic system. However, Everglade have received drainage water enriched with phosphorus (P) fertilizer over past 40 years, which has created the gradient of P content, TN:TP ratio, the pool and size of microbial population in the Water Conservation Area 2A (WCA-2A) in the northern part of Everglade ecosystem. Until recent, there was little information on how the nutrient change caused by P enrichment affected the inorganic N transformation rates and relationships between them in the Everglade wetland ecosystems. Thus, we studied the relationships between nitrification, anammox and denitrification rates in along a sediment P gradient in WCA-2A, a nutrient affected area of the Florida Everglades. The P-enriched site exhibited higher nitrification rates than did the transitional and un-impacted sites, and their activities were regulated by ammonium concentrations. Bacterial ammonia monooxygenase subunit A (amoA: AOB) nitrifiers were more numerous than archaeal amoA (AOA) nitrifiers and likely contributed most to sediment nitrification rates, which had positive correlations with ammonium concentration. Enhanced nitrification rate might supply more nitrite to anammox bacteria and enhance their activities, implying the possibly presence of coupled nitrification-anammox processes in wetland ecosystems. For nitrate reduction, labile organic carbon contents were positively correlated with sediment denitrification rates and abundances of nirS and nirK genes, and their activities and gene abundances were higher in the P-impacted and transitional sites than in the un-impacted site. Denitrification rates were much higher than anammox rates in sediment samples; however, the reverse was true in the water column. In summary, this study demonstrated that P-enrichment might enhance inorganic N transformation rates in wetland sediment ecosystem; however denitrification and anammox rates in the water ecosystems was not significantly affected by P-enrichment factors. In addition, the relative importance for N removal between denitrification and anammox was different from the water and sediment ecosystems in the Everglades wetland.

Variation in body condition of Alligator mississippiensis in Florida

We examined body condition (using Fulton’s K with snout-vent length and weight) for 482 American alligators (Alligator mississippiensis) collected from 14 aquatic sites in Florida in 2011 and 2012. An information-theoretic approach using Akaike information criterion (AIC) was used to select the best models for alligator body condition from a suite of seven candidate models created using combinations of trophic state (oligotrophic, eutrophic, hypereutrophic), sex, and alligators/km. Our top model included trophic state and alligators/km indicating that alligator body condition from sites classified as hypereutrophic and eutrophic (2.43 ± 0.07 and 2.45 ± 0.05, respectively) were greater than alligator body condition at oligotrophic sites (2.14 ± 0.01). Alligator body condition was lower at sites with a higher density of alligators ≥ 1.25 m. Across all sites, average alligator body condition ranged from 1.94 ± 0.054 (SE) to 2.78 ± 0.121(SE). This was a 43% difference in alligator body condition between the site with the highest alligator body condition (Lochloosa Lake, a hypereutrophic lake in north-central Florida) compared to the site with lowest body condition (Water Conservation Area 3B, an oligotrophic marsh in the Everglades). Across all sites, average alligator body condition was 12% greater at eutrophic and hypereutrophic sites compared to oligotrophic sites which was consistent with patterns observed in other studies for fish standing stock (highest in eutrophic lakes and lowest in oligotrophic marshes in the Everglades). The same patterns occur in alligator stomach content volume (higher in lakes in north-central Florida, Louisiana fresh, intermediate, and brackish marshes compared to the Everglades). Our results illustrate that variation in alligator body condition is consistent with patterns of aquatic site productivity and is a useful parameter for describing differences in aquatic site ecological condition.

Accounting for the Impact of Management Scenarios on Typha Domingensis (Cattail) in an Everglades Wetland.

The coupled regional simulation model, and the transport and reaction simulation engine were recently adapted to simulate ecology, specifically Typha domingensis (Cattail) dynamics in the Everglades. While Cattail is a native Everglades species, it has become invasive over the years due to an altered habitat over the last few decades, taking over historically Cladium jamaicense (Sawgrass) areas. Two models of different levels of algorithmic complexity were developed in previous studies, and are used here to determine the impact of various management decisions on the average Cattail density within Water Conservation Area 2A in the Everglades. A Global Uncertainty and Sensitivity Analysis was conducted to test the importance of these management scenarios, as well as the effectiveness of using zonal statistics. Management scenarios included high, medium and low initial water depths, soil phosphorus concentrations, initial Cattail and Sawgrass densities, as well as annually alternating water depths and soil phosphorus concentrations, and a steadily decreasing soil phosphorus concentration. Analysis suggests that zonal statistics are good indicators of regional trends, and that high soil phosphorus concentration is a pre-requisite for expansive Cattail growth. It is a complex task to manage Cattail expansion in this region, requiring the close management and monitoring of water depth and soil phosphorus concentration, and possibly other factors not considered in the model complexities. However, this modeling framework with user-definable complexities and management scenarios, can be considered a useful tool in analyzing many more alternatives, which could be used to aid management decisions in the future.

Assessment of Carbon Stocks in the Topsoil Using Random Forest and Remote Sensing Images.

Wetland soils are able to exhibit both consumption and production of greenhouse gases, and they play an important role in the regulation of the global carbon (C) cycle. Still, it is challenging to accurately evaluate the actual amount of C stored in wetlands. The incorporation of remote sensing data into digital soil models has great potential to assess C stocks in wetland soils. Our objectives were (i) to develop C stock prediction models utilizing remote sensing images and environmental ancillary data, (ii) to identify the prime environmental predictor variables that explain the spatial distribution of soil C, and (iii) to assess the amount of C stored in the top 20-cm soils of a prominent nutrient-enriched wetland. We collected a total of 108 soil cores at two soil depths (0-10 cm and 10-20 cm) in the Water Conservation Area 2A, FL. We developed random forest models to predict soil C stocks using field observation data, environmental ancillary data, and spectral data derived from remote sensing images, including Satellite Pour l'Observation de la Terre (spatial resolution: 10 m), Landsat Enhanced Thematic Mapper Plus (30 m), and Moderate Resolution Imaging Spectroradiometer (250 m). The random forest models showed high performance to predict C stocks, and variable importance revealed that hydrology was the major environmental factor explaining the spatial distribution of soil C stocks in Water Conservation Area 2A. Our results showed that this area stores about 4.2 Tg (4.2 Mt) of C in the top 20-cm soils.

Trace metals in the soils of Water Conservation Area of Florida Everglades: Considerations for ecosystem restoration

Purpose Inorganic contaminants present a major challenge for the restoration of aquatic ecosystems. The objectives of this study were to determine the extent of trace metal contamination and investigate the influence of different plant communities on trace metal accumulation in the soils of the Florida Everglades.

Microbial genetic and enzymatic responses to an anthropogenic phosphorus gradient within a subtropical peatland

Many of the world's peatlands are subject to agricultural runoff, which may impact fundamental biogeochemical processes by altering the concentrations of limiting nutrients. In this study, the distribution of specific microbial genes associated with phosphorus (P) and nitrogen (N) metabolism was compared with potential enzyme activities related to P and N acquisition at five stations along a nutrient gradient in soils of Water Conservation Area 2A (WCA-2A) of the Florida Everglades, USA. Quantitative PCR was used to compare the relative concentrations of genes encoding alkaline phosphatases (phoX and phoD) with those encoding dinitrogenase reductase (nifH). Combined phosphatase and phosphodiesterase (EP) activities were compared with leucine aminopeptidase activities (EN), yielding a measure of potential microbial investment in P acquisition relative to N acquisition. The significant inverse relationship observed between bicarbonate extractable organic P concentrations and ratios of gene copy numbers of phoX:nifH (p=0.049, R2=0.77), and phoD:nifH (p=0.043, R2=0.79), combined with the significant inverse relationship between total P and EP/EN (p=0.021, R2=0.87), suggest that there is a greater community selection towards P acquisition relative to N acquisition as bicarbonate extractable organic P and total P decrease, suggesting a shift from P limitation to N limitation along the transect. The total number of unique genes detected by the functional microarray GeoChip 3.0 was greatest in an intermediate site, suggesting that the alleviation of nutrient limitation yielded increased functional diversity. The general agreement between genetic and enzymatic data suggests that assessing microbial nutrient demands with molecular techniques is feasible, although future work is needed to apply genetic information as indicators of nutrient enrichment.