High Land Research Articles

Assessment of Lobster Resources in Coastal Region of Gulf of Mannar, Southeast Coast of India

Marine crustacean lobsters are one of the valuable delicacies of seafood which are in great demand in international markets. Due to their commodity value, several species of lobsters are in an endangered situation. To address this issue, the current study aimed to assess the lobster resources in the Rameshwaram, Mandapam, Keelakarai, Vembar and Tuticorin region coastal waters alongthe Gulf of Mannar, southern east coastal region of India using univariate and multivariate methods. From 2016 to 2017, population density examinations were conducted for both season-wise and station-wise contributions by lobster. A total of six lobster species (Panulirus homarus, P. ornatus, P. versicolor, P. polyphagus, P. penicillatus and Thenus unimaculatus) were recorded during January 2016–December 2017. Among the six species, Panulirus homarus, P. ornatus, and Thenus unimaculatus were found to be the dominant in contributing 70% of the total catch. In general, the ordination of CCA plot grouped with dominant species recorded from the surveyed stations. The results revealed that the stations of Gulf of Mannar region formed a unique cluster based on species along with its abundance and the five sites were clustered into two groups based on the habitat. This fact was further confirmed through MDS, which also revealed the same pattern of groupings as recognized in cluster analysis. Good quantities of spiny lobsters were landed throughout the year with higher landings during in and off monsoon seasons. Among the various species, P. versicolor was caught less in all seasons of both the years.

Environmental isotope constraints and hydrogeochemical evolution of groundwater in the semi-arid national capital environs of Delhi, India

Changes in hydrological regimes due to rapid urbanization and increasing anthropogenic stress on hydro-geological system creating an alarming condition for the management of ground water resources. Isotope and hydro-geochemical integrated approach has been used to determine the processes governing chemical composition of groundwater and the mechanism influencing the chemical composition of groundwater in National Capital Region (NCR), Delhi. The chemical evolution of groundwater has studied by using flow direction, hydro-chemical facies, bivariate plots of ionic ratios and saturation index. Stable isotopes and tritium are used to understand the recharge mechanism. Pollution index of groundwater (PIG) is also used to check the level of contamination in the groundwater. In total, 57 water samples were collected for water chemistry, 36 water samples for environmental isotopes and 13 samples for tritium measurement. The dominant water type is Ca-Mg-HCO3 and mixed water type. The dominant cation are Ca2+ > Na+ > Mg2+ > K+ and dominant anions are HCO3− > Cl− > SO42− > NO3−. The bicarbonate type water is dominant in quartzite, implies rapid and direct recharge through fracture and joints. Ionic ratios and saturation indices show that major processes controlling groundwater evolution are silicate hydrolysis and reverse cation exchange in the quartzite. Average values of δ2H and δ18O are −43.66 ‰ and −6.28‰. Stable isotopic ratio of groundwater of alluvium area falling on evaporation line, due to the prevailing semi-arid and arid climatic conditions, evaporation is the predominant factor affecting the chemistry of groundwater. The stable isotope shows that the groundwater in the quartzite is mostly meteoric in origin and acting as a recharge area for the nearby alluvium aquifer. Tritium results reveal that groundwater occurring in quartzite and alluvium aquifer in western parts are older than that of groundwater occurring in alluvium aquifer in the eastern parts.13% of groundwater samples are falling in very high pollution zone mainly occurring in alluvium aquifer that lies in the Eastern parts. It is inferred that alluvium aquifer (low lying) is having greater impact of anthropogenic activity than quartzite aquifer (high land).

MITIGATION OF LANDSLIDE PRONE AREAS IN ANTICIPATION OF CLIMATE CHANGE IMPACTS

In general, landslides occur when the upward slope is higher than the retaining force which is caused by high rainfall intensity, land slope, load and impermeable layer, soil solum thickness, and soil type. The restraining force is generally controlled by the resistance of soil shear, the density and strength of plant roots and the strength of rocks. This disaster also often occurs in Indonesia, which has many mountains that stretch across the country. This research aims to determine landslide-prone areas, landslide types, dominant factors that cause landslides and landslide mitigation in anticipation of the impact of non-structural climate change. The research included 3 stages, such as pre-field, field, and post-field which are interrelated and complementary. The research location is around landslide-prone lands along the southwest slope of Mount Lawu in Karanganyar Regency, Central Java. Based on the results of the research analysis, it indicates that the southwest slope of Mount Lawu, especially in Karanganyar, is highly prone to landslides. Therefore, it is not suitable to be used as agricultural and residential land because of its area of about 6,797.06 ha, and is categorized into three crucial parts, such as areas that are still highly prone to landslides of about 5,005.35 ha (73.64%); landslide-prone area of 1,784.23 ha (26.25%); and slightly landslide-prone area of 7.48 ha (0.11%).

Using watershed characteristics to enhance fecal source identification

Fecal pollution is one of the most prevalent forms of pollution affecting waterbodies worldwide, threatening public health and negatively impacting aquatic environments. Microbial source tracking (MST) applies polymerase chain reaction (PCR) technology to help identify the source of fecal pollution. In this study, we combine spatial data for two watersheds with general and host-associated MST markers to target human (HF183/BacR287), bovine (CowM2), and general ruminant (Rum2Bac) sources. Concentrations of MST markers in samples were determined with droplet digital PCR (ddPCR). The three MST markers were detected at all sites (n = 25), but bovine and general ruminant markers were significantly associated with watershed characteristics. MST results, combined with watershed characteristics, suggest that streams draining areas with low-infiltration soil groups and high agricultural land use are at an increased risk for fecal contamination. Microbial source tracking has been applied in numerous studies to aid in identifying the sources of fecal contamination, but these studies usually lack information on the involvement of watershed characteristics. Our study combined watershed characteristics with MST results to provide more comprehensive insight into the factors that influence fecal contamination in order to implement the most effective best management practices.

High-resolution patterns and inequalities in ambient fine particle mass (PM2.5) and black carbon (BC) in the Greater Accra Metropolis, Ghana

Growing cities in sub-Saharan Africa (SSA) experience high levels of ambient air pollution. However, sparse long-term city-wide air pollution exposure data limits policy mitigation efforts and assessment of the health and climate effects. In the first study of its kind in West Africa, we developed high resolution spatiotemporal land use regression (LUR) models to map fine particulate matter (PM2.5) and black carbon (BC) concentrations in the Greater Accra Metropolitan Area (GAMA), one of the fastest sprawling metropolises in SSA. We conducted a one-year measurement campaign covering 146 sites and combined these data with geospatial and meteorological predictors to develop separate Harmattan and non-Harmattan season PM2.5 and BC models at 100 m resolution. The final models were selected with a forward stepwise procedure and performance was evaluated with 10-fold cross-validation. Model predictions were overlayed with the most recent census data to estimate the population distribution of exposure and socioeconomic inequalities in exposure at the census enumeration area level. The fixed effects components of the models explained 48–69 % and 63–71 % of the variance in PM2.5 and BC concentrations, respectively. Spatial variables related to road traffic and vegetation explained the most variability in the non-Harmattan models, while temporal variables were dominant in the Harmattan models. The entire GAMA population is exposed to PM2.5 levels above the World Health Organization guideline, including even the Interim Target 3 (15 μg/m3), with the highest exposures in poorer neighborhoods. The models can be used to support air pollution mitigation policies, health, and climate impact assessments. The measurement and modelling approach used in this study can be adapted to other African cities to bridge the air pollution data gap in the region.

Assessing high quality agricultural lands through the ecosystem services lens: Insights from a rapidly urbanizing agricultural region in the western United States

Globally, as the human population increases, so does the demand for developable land. More than ever, agricultural land is being developed to meet housing and commercial needs, but at the same time is necessary for food security and other critical ecosystem services (ES). High quality agricultural lands (i.e. those which can support high yields, a diversity of crops, and are resilient to climate change) may play an important role in balancing the demand for housing, food, and other ES. In this paper, we used the Ecosystem Service framework to investigate the quality of agricultural lands beyond that of their value for food production. We conducted our study in the Treasure Valley, Idaho, where the issue of agricultural land loss is particularly relevant due to severe development pressure, few restrictions on land use, and limited arable land. We quantified the relationships between agricultural land quality and ES supply in 2016, and then measured how ES supply is likely to change in the future under a “Business as Usual” land use scenario. We found that higher quality agricultural land was associated with food provision, livestock crop production, and nitrogen retention, whereas lower quality agricultural land was associated with carbon sequestration, habitat quality, and recreation. Urban development is projected to occur disproportionately on higher quality agricultural land. Over 15 times more higher quality agricultural land will be developed between 2016 and 2050 compared to lower quality agricultural land. With the expected loss of agricultural land to development, the landscape in 2050 will have a lower supply of four of the six chosen ES compared to 2016. We found that livestock crop production will decrease the most over the time period (−28.8%) followed by food provision (−22.8%), nitrogen retention (−19.3%), and habitat quality (−7.4%). However, carbon sequestration (+5.5%) and recreation (+1.6%) will increase. Overall, we found strong evidence that certain ES are associated with varying levels of agricultural land quality and higher quality agricultural land was shown to be particularly vulnerable to urban development. Our results suggest the need to consider additional values of agricultural land beyond its use for food production. We recommend the implementation of policies that consider the trade-offs of developing on varying quality of agricultural land to help balance the many competing demands of our lands.

Suburban pastoralists: Pastoral adaptation strategies at the rural-urban interface in Nairobi, Kenya

How does urban expansion interact with pastoral climate change adaptation? This article explores pastoral adaptation strategies at the rural-urban interface. It examines how Maasai pastoralists in peri-urban Nairobi, Kenya, respond to climate hazards in the context of urban expansion, land use change, and land privatisation. Using mixed-method research, the study is informed by a household survey (n = 72), 38 qualitative interviews, and 12 focus group discussions. Drawing on the literature on climate change adaptation, pastoral change, and peri-urban dynamics, we find that while urban expansion provides significant challenges for pastoral livelihoods in the study area, pastoralists also engage new opportunities in the peri-urban context and employ them in their adaptation strategies. We show how adaptation strategies related to mobility, diversification, market exchange, and storage are employed through a variety of efforts including engagement with urban land markets and demand for livestock products, and by capitalising on proximity to transport, trading facilities, water, and commercial fodder. Communal pooling, another adaptation strategy, is less used and perceived to be in decline. We further find that historical land ownership patterns play a significant role in adaptation strategies, as pastoralists who have benefitted from rangeland privatisation are able to convert high peri-urban land values into private rural land access and investments in, e.g. diversification. Poor households are in a more precarious position but draw on informal agreements to access land as part of their adaptation strategies. Our findings highlight how pastoral households at the rural-urban interface may draw actively on peri-urban opportunities in their adaptation strategies as part of their efforts to enhance livelihoods, and in so doing bridge peri-urban and rural space. More broadly, our study highlights the importance of understanding pastoral climate change adaptation in the context of wider changes in livelihoods, land use, and land rights, rather than as isolated actions.Graphical

The preliminary study on the historical governing law of the frozen estates in Kampong Bharu, Malaysia

Kampong Bharu is situated in Kuala Lumpur, Malaysia and is categorised as a high commercial land located in the ‘Golden Triangle.’ However, this place is still left behind in terms of development as it is reported that there are more than RM60 billion in frozen estates. The existing legal framework is still considered inadequate as the planning development has been pending until today. Hence, this paper aims to analyse the legal history and the constraints preventing the development of Kampong Bharu. The discussion adopts the content analysis based on the qualitative research methods through the statutory provisions and other legal and non-legal literature. The research found that the Kampong Bharu Development Corporation Act 2011 was passed, and the Kampong Bharu Development Master Plan 2040 has been launched to carry out the development. Hence, it is proposed that the Kampong Bharu Development Corporation (KBDC) may have to wield the Land Acquisition Act 1960 so that the productive elements in Kampong Bharu can be activated. The impact of this research is in line with the benefit addressed by the Sustainable Development Goals (SDG) Plan (2030) in terms of making cities and human settlements inclusive, safe, resilient and sustainable.

Variation in soil organic carbon content and its dynamics under different cropping sequences and nutrient management practices in middle indo-gangetic plains

In the era when the population is escalating at a rapid rate while on other hand the land for cultivation is declining, there is tremendous pressure in high fertile lands like the Indo-Gangetic plains to produce food grains with intensified cropping. This intensification of agriculture has lead to stagnation of yield in cropping systems due to decline in soil organic matter and nutrient cycling. Soil organic carbon along with the microbial biomass are important indicators of physical, chemical as well as biological properties. This two parameters can be determined by various methods like dehydrogenase activity, soil respiration rate and microbial biomass calculation by chloroform and irradiation method. The current paper comprises of the study of different cropping systems in the Indo Gangetic plains in order to analyze its different organic carbon pool, relationship between them and different land use system that influences them. It was noticed that the system receiving both organic and inorganic fertilizers had higher total organic carbon, higher respiration rate, labile carbon along with higher microbial population. Under the nutrient management consisting of FYM + NPK fertilizer treatment there was increasing microbial biomass carbon and total organic carbon over other treatments because of more or higher root biomass. Therefore for a healthy soil and sustainable production system in high fertile and demand area of Indo Gangetic plain it is necessary to assess the soil organic carbon pools and maintain them by using integrated nutrient management.

Development of antifouling membrane film for treatment of oil-rich industrial waste

As the largest producers of palm oil, Malaysia disposes substantial amount of oil-rich industrial waste regularly. Untreated oil-rich wastewater reduces water quality and deteriorates aquatic ecosystems. Conventional method used in treating oil-rich waste involved precipitation, flocculation, coagulation, and biological treatment, which is disadvantageous due to the high cost, high chemical use, high land area required, and difficulty in maintaining the optimum condition for microorganisms’ growth. Membrane technology showed potential in treating oil-rich waste due to the low cost, efficiency, and environmentally friendly properties. However, long term usage of membrane may result in oil fouling which will lower membrane performance. The present study attempted to use methyl gallate extracted from Anacardium occidentale leaves to mitigate oil fouling and maintain membrane performance over time. As polar compound, methyl gallate increased the hydrophilicity of cellulose acetate membrane. The developed methyl gallate/cellulose acetate membrane exhibited PWF of 56.28 ± 2.10 L m-2h−1 and rejection rates of 99.14 ± 0.03 % against oil emulsion. The membrane was able to achieve FRR of 98.73 ± 0.83 % after 4 cycles of filtration, indicating that anti-fouling properties have been enhanced.

Efficient short time pretreatment on lignocellulosic waste using an isolated fungus Trametes sp. W-4 for the enhancement of biogas production

Biological pretreatment to the lignocellulosic waste prior to anaerobic digestion is a popular method to increase biogas production. However, the long time needed for the pretreatment is not suitable to the practical application. A fungus strain, which could produce many kinds of lignocellulosic enzymes including CMCase, FPase, xylanase and laccase, was isolated from the soil of Tibet in this study. The fungus was identified as Trametes sp. W-4 by morphological and molecular characterization. The optimum culture temperature was 30 °C and the optimum nitrogen source was peptone. Under the optimum fermentation condition, the activity of CMCase, FPase, xylanase and laccase could reach 2.73 U/mL, 0.41 U/mL, 0.29 U/mL, and 1.11 U/mL, respectively. The results of pretreatment of Trametes sp. W-4 on the mixtures of high land barley straw, cow manure and pig manure for enhancement of biogas production showed that a very short time pretreatment of 3 days could obtain the highest cumulative methane production of 111.51 mL/g-VS, which was 63.81% higher than that of the control group of 68.07 mL/g-VS. The finding indicated that Trametes sp. W-4 pretreatment could be a candidate for the improving of biogas production from lignocellulosic waste.

Effect of PGPR on Growth and Yield of Ginger through Rhizome Rot Management in Eastern Ghat High Land Zone of Odisha

Effect of PGPR on Growth and Yield of Ginger through Rhizome Rot Management in Eastern Ghat High Land Zone of Odisha

CHELSA-TraCE21k – high-resolution (1 km) downscaled transient temperature and precipitation data since the Last Glacial Maximum

Abstract. High-resolution, downscaled climate model data are used in a wide variety of applications across environmental sciences. Here we introduce a new, high-resolution dataset, CHELSA-TraCE21k. It is obtained by downscaling TraCE-21k data, using the “Climatologies at high resolution for the earth's land surface areas” (CHELSA) V1.2 algorithm with the objective to create global monthly climatologies for temperature and precipitation at 30 arcsec spatial resolution in 100-year time steps for the last 21 000 years. Paleo-orography at high spatial resolution and for each time step is created by combining high-resolution information on glacial cover from current and Last Glacial Maximum (LGM) glacier databases and interpolations using data from a global model of glacial isostasy (ICE-6G_C) and a coupling to mean annual temperatures from TraCE21k (Transient Climate Evolution of the last 21 000 years) based on the Community Climate System Model version 3 (CCSM3). Based on the reconstructed paleo-orography, mean annual temperature and precipitation were downscaled using the CHELSA V1.2 algorithm. The data were validated by comparisons with the glacial extent of the Laurentide ice sheet based on expert delineations, proxy data from Greenland ice cores, historical climate data from meteorological stations, and a dynamic simulation of species distributions throughout the Holocene. Validations show that the CHELSA-TraCE21k V1.0 dataset reasonably represents the distribution of temperature and precipitation through time at an unprecedented 1 km spatial resolution, and simulations based on the data are capable of detecting known LGM refugia of species.

Climate action at the neighbourhood scale: Comparing municipal future scenarios

Municipalities face the direct impact of climate change events, but many are challenged to assess the potential outcomes of future climate action policies. It is essential for local municipalities to be able to evaluate cross-sector and cross-scale policy interventions, but many lack the expertise and resources for wholistic forecasting. This paper used a hybrid inter-scalar and interdisciplinary modeling approach to evaluate, compare, visualize, and reveal the performance of climate actions at building and neighbourhood scales of future ‘what-if’ scenarios for three neighbourhood urban form types (dispersed, corridor, nodal) in three cities in British Columbia, Canada (Vancouver, Victoria, Prince George). Results found that increases in population density combined with strict building standards and retrofitting older buildings decreased per person emissions per year by up to 84% by 2050. Within the neighbourhood-scale areas, building form and location had less impact. Population density and frequency of transit service were most important for mobility mode shifts. Concentrating density at transit nodes or along commercial corridors improved the percentages of residents within a five-minute walk of those services, but proximity to greenspaces showed mixed results. <em><strong>Policy relevance</strong></em> Municipal climate action policies cross sectors and scales. This analysis of future urban form and energy scenarios at neighbourhood scales reveals livability and greenhouse gas (GHG) outcomes. It provides evidence that compact neighbourhood form coupled with stringent building codes reduces GHG emissions. (1) Concentrating density at transit nodes or along commercial corridors improved the percentages of residents within a five-minute walk of those services, but proximity to greenspaces showed mixed results. (2) Within neighbourhood-scale areas urban form (building form and location) had less influence on shifting mobility modes than did overall population density and transit frequency. (3) British Columbia’s net-zero-ready building code, a performance-based code, resulted in notable energy-use reductions and related emissions reductions associated with the new building stock. (4) Retrofitting the existing building stock resulted in notable emissions reductions in the three neighbourhoods; however, for cities with growing high land value, the potential for sale and redevelopment is a disincentive to retrofitting.

Endangered Curcuma caesia Roxb.: Qualitative and quantitative analysis for identification of industrially important elite genotypes

Black turmeric (Curcuma caesia Roxb.) of Zingiberaceae family is an industrially important critically endangered herb, found to have a captivating influence in the realm of traditional medicine. Now that this species is enlisted under critically endangered category and the repercussion of its unavailability in the terrestrial flora exempts us from scientifically exploring its potential biochemical constituents in terms of pharmaceutical and other industrial uses. So, in the present study, the industrially important qualitative and quantitative traits of black turmeric (n = 50) from different climatic zones were studied to select elite genotypes with respect to high anthocyanin and essential oil content. The genotype of Koraput was found to yield high anthocyanin content (7.14%) and high leaf oil content (1.25%) while genotype of Deoghati yields high rhizome oil content (2.55%). The quality analysis of essential oil by Gas Chromatography-Mass Spectroscopy showed the presence of eucalyptol and camphor as major compounds in leaf and rhizome oils respectively. The selected elite genotypes mostly belong to North Western Plateau, North Eastern Ghat, Eastern Ghat High Land, and South Eastern Ghat agroclimatic zones. Further, 5 elite genotypes from 4 different agroclimatic zones were recommended as industrially important high yielding traits (Anthocyanin > 6%, leaf oil ≥ 1.2%, rhizome oil >1.5%, eucalyptol >20%, and camphor >21%.) and found to be most favourable for the cultivation.

Comparison between the ASTER and ECOSTRESS global emissivity datasets

High spatial resolution global land surface emissivity datasets are valuable for various applications. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Emissivity Dataset (GED) is the only accessible global emissivity data with a high spatial resolution (∼100 m). Since the launch of the ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) in June 2018, another high spatial resolution GED can be generated. A comprehensive comparison is needed to investigate the consistency between the ASTER and ECOSTRESS GEDs before subsequent applications and the release of the ECOSTRESS GED. We conducted a first-ever comparison between the ASTER and ECOSTRESS GEDs in two ways: 1) global spatial comparison and 2) validation using emissivity measurements at 9 sand dune and 2 vegetated sites. The results reveal that the ECOSTRESS emissivities in bands 2 and 4 are in good agreement with ASTER GED, with mean absolute biases (MAB) of ∼ 1 % averaged over the globe. The emissivity difference is the largest for snow and ice in these two bands. For band 5, the discrepancy is relatively larger with a MAB of 1.7 %. The largest emissivity difference is found over evergreen broadleaf forests in humid regions. Comparison with measurements reveals an average root-mean-square error (RMSE) of ECOSTRESS emissivity of ∼ 3 % among all the nine sand sites for all the 3 bands. At the two vegetated sites, the average RMSE is ∼ 1.5 %. The absolute biases are below 3 % in all the bands. The average RMSE between ASTER and ECOSTRESS GEDs among all sand dune sites is 1.29 %. The evaluation results demonstrate a good agreement between these two emissivity retrievals overall and high accuracy of the ECOSTRESS GED.

A Time-Domain Planning Method for Surface Rescue Process of Amphibious Aircraft for Medium/Distant Maritime Rescue

Medium/distant maritime rescue is significantly important in the development of maritime business. For typical medium/distant maritime rescue, the range limitation of helicopters and many difficulties between helicopter and ship cooperation lead to unsatisfactory rescue results. Compared to helicopters and ships, amphibious aircrafts could effectively solve the problems faced by helicopters and ships and meet the medium/distant maritime rescue demands with their long cruise range, high speed, high rescue capability and surface landing capability. Therefore, a time-domain planning method (TPM) based on the k-means* clustering algorithm and the genetic algorithm* is proposed in this study for the surface rescue process (SRP) of amphibious aircrafts in medium/distant maritime rescue. To simulate the SRP of amphibious aircrafts, an agent-based simulation environment of medium/distant maritime rescue was constructed based on the Python platform. Finally, a case study was carried out to verify its effectiveness and applicability. The results show that the TPM exhibits satisfactory rescue results for the SRP of the amphibious aircraft and that less than 1 h of delay time is recommended for the amphibious aircraft to rescue the persons in distress by using TPM.

Analysis of Spatial-Temporal Differentiation and Influencing Factors of Ecosystem Services in Resource-Based Cities in Semiarid Regions

The spatial-temporal differentiation characteristics and driving mechanisms of ecosystem services are of great significance for optimizing the pattern of land spatial protection and realizing regional sustainable development. Existing studies seldom consider the segmental influence mechanism of various influencing factors on different levels of ecosystem service value (ESV). Therefore, this paper analyzes the temporal and spatial differentiation evolution characteristics of ESV in semiarid regions through an improved ESV evaluation model. The spatial panel quantile regression (SPQR) model was introduced to explore the relationship between various types of influencing factors and ESV in different intervals. The results showed the following: (1) The changes in ESV in Baotou City from 2000 to 2018 tended to be stable, but the spatial differentiation of ESV intensified. The aggregation feature of the low-ESV region is significant and gradually expanding. (2) Precipitation was the dominant factor increasing the ESV in each interval, and temperature had a significant negative impact on the low-ESV area. (3) Higher land use integrity accelerates the decline of ESV in the surrounding areas of built-up areas. The high-ESV area was more sensitive to the intensity of human activity. The direction of human activities should be effectively controlled, and the structure of comprehensive land use should be optimized to enhance the service function of regional ecosystems. This research provides new thinking for the ecological restoration zoning of regional territorial spatial planning and the sustainable development of resource-based cities.

Groundwater‐stream connections shape the spatial pattern and rates of aquatic metabolism

AbstractA longstanding challenge in stream ecology is to understand how landscape configuration organizes spatial patterns of ecosystem function via lateral groundwater connections. We combined laboratory bioassays and field additions of a metabolic tracer (resazurin) to test how groundwater‐stream confluences, or “discrete riparian inflow points” (DRIPs), regulate heterotrophic microbial activity along a boreal stream. We hypothesized that DRIPs shape spatial patterns and rates of aquatic heterotrophic microbial activity by supplying labile dissolved organic matter (DOM) to streams. Laboratory bioassays showed that the potential influence of DRIPs on heterotrophic activity varied spatially and temporally, and was related to their DOM content and composition. At the reach scale, DRIP‐stream confluences elevated the spatial heterogeneity and whole‐reach rates of heterotrophic activity, especially during periods of high land–water hydrological connectivity. Collectively, our results show how the arrangement of lateral groundwater connections influence heterotrophic activity in streams with implications for watershed biogeochemical cycles.

Associations of home and neighborhood environments with children’s physical activity in the U.S.-based Neighborhood Impact on Kids (NIK) longitudinal cohort study

IntroductionPhysical activity is important for children’s health and well-being. Supportiveness for physical activity of home and neighborhood environments may affect children’s PA, but most studies are cross-sectional. We examined environmental predictors of change in children’s physical activity over two years.MethodsData were from the longitudinal, observational cohort study, ‘Neighborhood Impact on Kids’. Participants were children (initially aged 6–12 years) and their parent/caregiver (n = 727 dyads) living in neighborhoods throughout San Diego County, California and King County (Seattle area), Washington, USA. Children’s moderate-to-vigorous physical activity (MVPA) was measured using accelerometers at T1 (Time 1 or baseline, 2007–2009) and T2, the two-year follow-up. At T1, parents survey-reported on physical activity (PA) equipment at home and demographics. Neighborhood environment was measured using spatial data in Geographic Information Systems (intersection density; park availability) and in-person audits (informal play space near home; park-based PA facilities; land use; support for walking/cycling). Generalized additive mixed models estimated total effects, then direct effects, of environmental attributes on MVPA at T1. Two-way moderating effects of child’s sex and age were examined at T1. To examine associations of environmental exposures with changes in MVPA, we estimated interaction effects of environmental attributes on the association between time and MVPA.ResultsOn average, children accumulated 146 min/day (standard deviation or SD = 53) of MVPA at T1, and 113 (SD = 58) min/day at T2. There were no significant total or direct effects of environmental attributes on MVPA at T1, and no significant two-way interaction effects of child’s age and sex for T1 MVPA. Having informal play spaces proximal to home with more amenities was associated with less MVPA decline from T1 to T2. Higher residential density, higher land use mix, and higher number of PA facilities in nearby parks were unexpectedly associated with greater MVPA decline.ConclusionHigher quality informal play spaces close to home may help offset declines in MVPA during middle childhood, as they may promote unstructured active play with opportunities for parental or neighbor surveillance. Unexpectedly, environmental factors consistent with higher walkability were associated with greater declines in children’s MVPA. As physical activity differs across the lifespan, so may environmental factors that facilitate it.