Sand Substrate Research Articles

Evaluating the Growth Response of Ricinus communis L. Cultivars to Salt Stress Using a Fast and Reliable Bioassay

AbstractHere is proposed an easy, fast, and economic technique to investigate plant physiological traits in response to salt stress by using castor bean (Ricinus communis L.). Four Ricinus communis L. cultivars (TUNI 1, TUNI 4, C1012, and C1028) were grown in a growth chamber for 15 days on a sand substrate and were watered regularly with deionised water or NaCl solution (water electrical conductivity (EC) 4, or 8 dS m− 1) to keep soil moisture close to field capacity. According to roots, stem, and germination traits and derived indices, TUNI 1 and TUN4 showed the best growth performance on sand irrigated with 4 dS m− 1 and 8 dS m− 1, respectively. Besides, comparing C1028 and C1012, the former showed a higher tolerance at the maximum electrical conductivity tested related to the latter, increasing salt tolerance index (STI) of roots (+ 25%) and stem (+ 20%). In conclusion, the present findings suggest that the TUNI 4 cultivar of Ricinus communis L. demonstrates superior overall performance, even under highly saline conditions, such as irrigation with 8 dS m− 1. Conversely, the TUNI 1 cultivar shows a good ability to perform in marginal soils with moderate salinity levels, such as those irrigated with 4 dS m− 1. Our results represent the first step towards optimization of a cost-effective method/bioassay for the selection of salt tolerant Ricinus communis L. cultivars and genotypes.

Character and Evolution of Sunken Groundwater-Harvesting Agroecosystems in Aeolian Sand since Early Islamic Times, between Iran and Iberia

ABSTRACT By reviewing traditional, sunken, groundwater-harvesting agroecosystems (SGHAS) in coastal and inland aeolian sand situated in Iran, Egypt, Gaza Strip, Algeria and Iberia, coupled with image interpretation and geospatial analysis, we study the innovation and function of recently excavated Early Islamic (EI; tenth-twelfth century), Plot-and-Berm agroecosystems along the southeastern Mediterranean coast of Israel. The SGHAS and EI agroecosystems, usually affiliated with nearby towns, possess an aeolian sand substrate enrichened with urban refuse and/or organic material. The long-term investment in SGHAS attained profitable water security in the form of temporally continuous, shallow groundwater, replenished by rainfall. The crops in SGHASs include a wide range of vegetables, watermelons, dates and grapes, implying that the EI crops were partly or fully different. The spotty, historic appearance of SGHAS since the fifteenth–sixteenth centuries temporally lags after the abandonment of the EI agroecosystems, does not support spatial and temporal connectivity of sand agriculture knowledge, but probably exemplifies the appearance of site-specific ingenuities derived from growing agro-technological knowledge, crop variety and needs for food security. This study demonstrates the importance of traditional analogues for interpreting research gaps of archaeological, agricultural landscapes and provides insight for establishing traditionally-based, sustainable agriculture in sand.

Slightly Saline Water Improved Physiology, Growth, and Yield of Tomato Plants in Yellow Sand Substrate

Efficient utilization of saline water and yellow sand resources can enhance water and soil resource management while boosting crop yields in Xinjiang. This study conducted a two-season field experiment in Alar City, Xinjiang, from March to July 2023 and August 2023 to January 2024. The objective was to examine the effects of different irrigation water salinities (2, 3, 4, 5, and 6 g·L−1) on the physiology, growth, and yield of sand-cultured tomatoes grown in yellow sand slag. Groundwater irrigation with salinity levels of 0.8–1 g·L−1 was used as the control (CK). The results showed that the salinity of the substrate gradually increased with the salinity of irrigation water in each treatment. The salt accumulation increased by 59.5%, 82.5%, and 99.5% at the end of the experiment for T3 (4 g·L−1), T4 (5 g·L−1), and T5 (6 g·L−1), respectively, compared to CK. As the salinity of irrigation water increased, plant height, stem thickness, chlorophyll content, net photosynthesis rate, stomatal conductance, transpiration rate, and total yield of tomato showed an increasing and then decreasing trend, in which the total tomato yield of the T2 (3 g·L−1) treatment was significantly increased by 35.2% compared with that of CK between the two seasons. In contrast, as the salinity of irrigation water increased, the inter-cellular CO2 concentration of tomato leaves showed a decreasing and then increasing trend, with the T2 treatment having the lowest inter-cellular CO2 concentration. Pathway analysis revealed that appropriate salinity levels increased tomato yield by regulating inter-cellular CO2 concentration. Based on these findings, a 3 g·L−1 salinity level is recommended for irrigating sand-cultured tomatoes to maximize yellow sand resource use, address freshwater shortages, and optimize water and soil management in the Xinjiang region.

Seabed classification in Bahía de Navidad in the Mexican Central Pacific using a single-beam echosounder

This study proposes a methodology for characterizing subtidal habitats along rocky coastlines and adjacent seabeds in the epipelagic zone using a 120 kHz single-beam echo sounder (SBES). The data collected at depths of 15 to 80 m in Bahía de Navidad on the Mexican Central Pacific coast were postprocessed and classified using QTC Impact™ software to obtain three acoustic classes.Using the classified data and ArcMap™ software, a bathymetric map was built for the selection of 19 sampling points for ground truthing and granulometric analysis to create a matrix further subjected to two ordination analyses: principal component analysis (PCA) and nonmetric multivariate scaling analysis (MDS). Additionally, the matrix was adapted into a dummy matrix, which was subsequently used to conduct a Pearson correlation coefficient test.The analyses revealed a strong correlation between the medium-deep-zone acoustic class (20 m to 50 m) and the medium-grain-size sand substrate, as well as a high correlation between the deep-zone acoustic class (50 to 80 m) and finer sand substrates. This study demonstrated the potential of using affordable echosounders as a reliable and feasible alternative for characterizing marine habitats, especially for research institutions in developing countries with limited financial resources.

Machine Learning and Taguchi Techniques for Predicting Wear Mechanisms of Ni-Cu Alloy Composites

Nickel-Copper alloys hybrid composite was formed in an induction furnace set up on a sand substrate. With different percentages of Al2O3 (3, 6, 9 and 12 wt.%) and TiO2 (constant 9wt.%) reinforcements, the goal is to examine the wear behavior and friction coefficient of Ni-TiO2-Al2O3. The factors considered for the wear analysis were sliding distance (1500, 1000, and 500 m), applied load (25, 50, and 75 N), and sliding velocity (1.46, 2.93, and 4.39 m/sec). The pin-on-disc equipment is utilized to perform different wear tests are carried out using in accordance with the Taguchi L27 orthogonal array. The machine learning used to correlate between actual and anticipated values for both metrics is strong, with a reasonable error margin. The Mean Squared Error (MSE) for the wear rate was 0.1025 (10.25%) in the Linear Regression model and 0.2390 (23.89%) in the Random Forest model. Regression analysis determined the impact of several parameters on wear rate, whilst machine learning approaches expanded the evaluation of wear rate and coefficient of friction beyond experimental data. The findings demonstrate the effectiveness of combining Taguchi methods with machine learning to accurately anticipate wear mechanisms in Ni-Cu alloy composites.

MEGA GASTROPODA ASSOCIATION IN THE MONOSPECIFIC SEAGRASS MEADOWS OF BADAK BADAK ISLAND, BONTANG CITY

Mega Gastropods play an important role in the food chain in bottom waters. Mega Gastropods are associated with seagrass beds which have sand and sandy mud bottom substrates. The aim of the research is to determine the association of Mega Gastropods in monospecific seagrass beds as their habitat. This research was carried out from October 2023 - February 2024 in the seagrass beds of Badak Badak Island. The station is divided into 3 stations and each station is divided into 3 zones. Seagrass and Mega Gastropod samples were taken using a 50x50cm quadrant frame. The relationship between seagrass density and Mega Gastropod density was used by the Pearson's Product Moment correlation test and the distribution of basic substrate fractions and the distribution of Mega Gastropod species was used by Principal Component Analysis (PCA) and Corespondence Analysis (CA). The Mega Gastropods found consisted of L. turturella, C. tigris, P aluco, and T. telescopium. The relationship between Mega Gastropod density and E. acoroides density was not positively correlated and the presence of Mega Gastropod species was associated with the characteristics of the basic substrate fraction.

Human walking biomechanics on sand substrates of varying foot sinking depth.

Our current understanding of human gait is mostly based on studies using hard, level surfaces in a laboratory environment. However, humans navigate a wide range of different substrates every day, which incur varied demands on stability and efficiency. Several studies have shown that when walking on natural compliant substrates there is an increase in energy expenditure. However, these studies report variable changes to other aspects of gait such as muscle activity. Discrepancies between studies exist even within substrate types (e.g. sand), which suggests that relatively 'fine-scale' differences in substrate properties exert quantifiable influences on gait mechanics. In this study, we compare human walking mechanics on a range of sand substrates that vary in overall foot sinking depth. We demonstrate that variation in the overall sinking depth in sand is associated with statistically significant changes in joint angles and spatiotemporal variables in human walking but exerts relatively little influence on pendular energy recovery and muscle activations. Significant correlated changes between gait metrics are frequently recovered, suggesting a degree of coupled or mechanistic interaction in their variation within and across substrates. However, only walking speed (and its associated spatiotemporal variables) correlate frequently with absolute foot sinkage depth within individual sand substrates, but not across them. This suggests a causative relationship between walking speed and foot sinkage depth within individual sand substates is not coupled with systematic changes in joint kinematics and muscle activity in the same way as is observed across sand substrates.

Gone with the flow: Whitefish egg drift in relation to substrate coarseness under a range of flow velocities.

Most major rivers in Europe have been dammed for hydropower or other purposes. Such river alterations have decimated natural reproduction of many migratory fish species, including that of the anadromous European whitefish, Coregonus lavaretus, which is now maintained by extensive stocking programmes. In addition to stocking, limited natural reproduction may occur downstream of dams, where peak flow bouts from the dams threaten to flush the eggs into unsuitable habitats. Here, we assessed the effects of water flow velocity and substrate coarseness on downstream drift of whitefish eggs under laboratory conditions. The experiment's two different gravel substrates retained eggs better than cobble or sand substrates; the water velocity needed for notable egg drift was higher for the gravel substrates. The results indicate that egg drift is one of the factors that should be considered when evaluating the effects of hydropower plant operations. Moreover, measures mitigating the effects of the artificial flow regimes should incorporate the type and coarseness of the riverbed's substrate.

Relationships between environmental variables and fish functional groups in impounded reaches of the Upper Mississippi and Yangtze Rivers

Large rivers throughout the world have been transformed by anthropogenic stressors that are known to influence the structure and composition of fish assemblages. Management of large rivers requires balancing socio-economic and political considerations with biodiversity conservation efforts. By exchanging best management practices between rivers, management efforts can be improved. However, data limitations have largely prevented comparative analyses among fish assemblages in large rivers, potentially limiting the effectiveness of shared management strategies. To improve understanding of the similarities and differences between the Upper Mississippi and Yangtze Rivers, we (1) compared environmental variables and functional traits of fish assemblages between the two systems, (2) identified traits responsible for distinguishing functional groups from one another, and (3) investigated relationships between similar functional groups of fishes and environmental variables to establish expectations for how fish assemblages in large rivers might respond to anthropogenic stressors. Regional species pools in the Upper Mississippi and Upper Yangtze Rivers were characterized by a similar composition of functional traits; the majority of species were omnivorous, had affinities for gravel or sand substrates, and produced sinking eggs. Few species were pelagic, planktivorous, or herbivorous. Functional groups in both rivers were primarily distinguished according to species' trophic habits and substrate preferences, with secondary contributions from species’ water column positions and life history characteristics. Pelagic planktivores and small-bodied guarders with an affinity for structural habitat complexity tended to increase downriver in both systems, in direct association with total phosphorus concentrations, agricultural land use, and temperature. In contrast, proportions of lithophilic species with affinities for gravel or cobble substrates were highest in segments located furthest upriver. By highlighting the sensitivity of different groups of fishes to anthropogenic stressors, we provide insights into the functional ecology of fishes inhabiting the Mississippi and Yangtze Rivers.

Community Structure of Sea Cucumbers (Holothuroidea) in The Intertidal Zone of Koepisino Beach, North Buton

Sea cucumbers are marine invertebrates belonging to the class Holothuroidea, living in various aquatic environments ranging from shallow coastal waters to deep seas. Sea cucumbers have an important ecological function in coral reef ecosystems. The aim of the research is to determine the community structure of sea cucumbers (Holothuroidea) in the intertidal zone of Koepisino Beach, North Buton. The research method used was quantitative descriptive research conducted in the intertidal zone of North Koepisino Buton Beach. Data collection was carried out by exploring each station measuring 50 × 100 meters for 3 stations. Data analysis was descriptive quantitative, In the intertidal zone of Koepisino Beach, North Buton, 12 species of sea cucumbers belonging to two orders, Aspidochirotida (genera Holothuria, Bohadschia, Telonata, and Stichopus) and Apodida (genera Synapta and Opheodesoma), were discovered. The community structure components analyzed in this study were abundance, diversity index, uniformity index, and dominance index.The highest abundance of sea cucumber species was at station I (sand substrate) at 0.009 (ind/m2). The lowest species abundance was at station III (coral rubble substrate) at 0.005 (ind/m2). H. scabra is the species with the highest abundance, namely 0.0026 ind/m2, while Bohadschia similis, Bohadschia vitiensis, Opheodesoma spectabilis, Telonata ananas are the species with the lowest abundance, namely 0 ind/m2. The Shannon-Wiener sea cucumber diversity index (H') is in the medium category 2.144. The sea cucumber uniformity index at the research location is high (E > 0.6) and there is no dominant species.

Effects of sand substrate removal on the intestinal antioxidant and metabolism in Marsupenaeus japonicus

M. japonicus is an important specie for factory farming, and factory farming requires an environment with sand at the bottom of the pond. However, the physiological responses as well as survival in the process of factory farming without laying sand are currently unknown. In the present study, we explored the effect of sand substrate removal on the intestinal histomorphology, antioxidant enzyme activity, and metabolic profile of M. japonicus. Our results indicate a gradual increase in the mortality rate of kuruma shrimp in ponds lacking sand substrate. The intestinal mucosa exhibited necrosis and the presence of vacuoles, with their number gradually increasing over time. The intestinal villi showed significant erosion, accompanied by a decrease in intestinal superoxide dismutase (SOD) activity and catalase (CAT) activity, and consistent with an upregulation in the expression of apoptosis-related genes such as caspase-3, indicating an adaptive response to the adverse environmental conditions. Additionally, the metabolomic analysis revealed that most significantly differential metabolites were linked to amino acid and lipid metabolism. These findings enhance our understanding of the sand substrate removal on the intestinal health of kuruma shrimp, which provides a basis for the factory farming.

Impacts of the cyromazine emergence inhibition procedure of Bactrocera dorsalis on Fopius arisanus: implications for the biological control of diptera pest.

Fopius arisanus (Sonan) is an important egg-pupal endoparasitic wasp of Bactrocera dorsalis (Hendel). As traditional method of sorting nonparasitic B. dorsalis from parasitic wasps is labor-intensive, requires specific equipment and poses the risk of spreading fertile hosts, the development of a more convenient, economical and safe sorting procedure is important. The optimal cyromazine emergence inhibition procedure (CEIP) involved facilitating the pupation of B. dorsalis mature larvae (Bdml) in 3 mg kg-1 cyromazine sand substrate (CSS) for 48 h. When the Bdml that had been exposed to F. arisanus during the egg stage were treated with 3-7 mg kg-1 CSS for 48 h, no negative effects on the emergence parameters of parasitoids were observed. Treatment with 3-4 mg kg-1 CSS had insignificant effects on the biological and behavioral parameters of F. arisanus. However, treatment with 5-6 mg kg-1 CSS adversely affected the fecundity and antennating activity of the wasps; specifically, 6 mg kg-1 CSS negatively affected the lifespan and flight ability of wasps. Fortunately, no transgenerational effects on these parameters were observed in the progeny. Regarding the nutrient reserves of both sexes of F. arisanus, significant dose-dependent effects were observed. Moreover, 5-6 mg kg-1 CSS significantly reduced the protein and carbohydrate content in F. arisanus; in particular, 6 mg kg-1 CSS notably reduced the lipid content. CEIP provides a more flexible, economical and safe mass-release program for F. arisanus. In addition, it has profound implications for the biological control of other dipteran pests. © 2024 Society of Chemical Industry.

Influence of different substrates on bacterial communities in coral reefs and surrounding environments of a coastal bay

Substrate types are diverse in coastal coral reefs, which can determine the distribution pattern of marine benthic organisms. Coastal coral reefs are also increasingly influenced by activities from the intertidal zone. However, the variation of bacterial communities on different substrates from the intertidal zone to coastal coral reefs have been seldom discussed. Here, we collected 12 samples of different substrate (rock, sand, live coral, and dead coral) from three environments (i.e., intertidal zone, coral distribution area, and no-coral distribution area) in Daya Bay of the South China Sea, and investigated the influence of substrates on bacterial communities. The results showed that the bacterial diversity (Shannon and Chao 1 index) in sand substrates was higher than those in stone/hard substrates. However, a more complex co-occurrence network of bacterial communities were observed in intertidal sand samples than sand samples from the coral area. Principal coordinate analysis and taxonomic analyses of bacterial composition showed that substrate type can shape the variations in bacterial communities from different environments in the Daya Bay region. Bacteroidetes and Chloroflexi were more abundant in sand substrates, while Cyanobacteria and Planctomycetes were more abundant in rock substrates. Redundancy analysis revealed that environmental factors, such as gravel, heavy metals, salinity, and pH regulated the bacterial community in the coastal region. Furthermore, the shared operational taxonomic units (OTUs) from different substrates in the coral distribution area were identified, and most of the top 20 shared OTUs (core bacteria) were identical to the bacteria associated with coral reef ecosystems in previous studies; thus, indicating that core bacteria exist in coral reefs from Daya Bay. This study broadens the understanding of the effect of substrates on bacterial distributions in coral reefs and surrounding environments from a coastal bay.

Colonial Ascidian Populations at Inshore Coral Reefs of Norfolk Island, South Pacific

Subtropical coral reefs such as the lagoonal reefs of Norfolk Island in the remote South Pacific are vastly understudied, with many benthic species unrecorded in the scientific literature. Here we report on ascidian populations from 2021 to 2023 at Norfolk Islands inshore reefs. Quantitative assessments spanning that period were conducted to assess ascidian presence, cover, and benthic interactions. We show ascidian cover remained persistently low and stable across the lagoonal reefs during the study period. We find adjacent reef site, Cemetery Bay showed variation in ascidian cover over time, where we measure a 3.2-fold increase in cover over 2 years. Ascidians were associated primarily with sand and sediment substrates at all reef locations. Recorded interactions between hard corals and ascidians were low. This study provides valuable insights into the population dynamics of ascidians within subtropical reef ecosystems. Ongoing ascidian population monitoring can provide a comprehensive understanding of ascidian dynamics whilst also providing insight of theimpact of anthropogenic stressors on benthic communities. Together, this can aid in informing management and conservation strategies for subtropical reefs.

IMPROVEMENT OF ELEMENTARY COMPONENT OF DAMAGED SUBSTRATES BY SAPONITE CLAY INCLUSION

In this proposed article, the impact on the elemental composition of sand substrates is determined using the example of the Andriykovetskyi quarry-dump complex and the Barsukivskyi sand pit, which are located in the Central Podillya region in the conditions of the Right-Bank Forest-Steppe. It was determined, that saponite clay contains a significant amount of macro- and micro- elements, and the directions of this use depend on the composition and origin of saponite: in agriculture, in industry, in construction, an application as a sorbent or as meliorant, etc. It is noted that the use of saponite as an ameliorant is an economical and cost-effective method of reclamation, which allows to reduce the burden on the environment caused by the extraction of minerals, pollution of the territory by heavy metals, the conduct of hostilities, etc. General scientific (analysis), statistical (statistical analysis) and laboratory methods (Fourier-transform spectroscopy) were used to assess the qualitative composition of inorganic and organic components of sand-saponite mixtures and to determine saponite clay as a potentially fertile material. To conduct the research, an averaged sample of sand was taken from the Andriykovetskyi quarry and dump complex and from the Barsukivskyi sand pit. For comparison with reference values, a zonal soil sample was taken from undisturbed areas. Saponite from the Tashkiv deposit with a fraction of 0.1 mm was used for sand-saponite mixtures, the ratio of sand substrate to saponite is 70% to 30%. According to the results of the study of the qualitative composition of the inorganic component, it was determined, that saponite has a positive effect on the composition of the sand-saponite mixture in terms of providing plants with nutrients, such as macro- and micro- elements (Mg, K, Na, Cu, Zn, Ca). This confirms the positive effect of saponite on plant growth, which was obtained by us in previous biotesting experiments, and is explained by the fact that the elements of the sand-saponite substrate are available to plants as a result of their transition into the substrate solution. Adding saponite to the substrate of sand pits also increases the content of organic substances, which accelerates the processes of humification and the formation of soil aggregates: humic acid contributes to the bonding of soil particles; carbohydrates sucrose, fructose, glucose and lactose create a nutrient environment for plants; stearates and stearic acid are the main soap components, lauric acid is a foaming catalyst, their presence in sand-saponite mixtures indicates their transition from saponite. When comparing the samples of sand-saponite mixtures of the Andriykovetskyi quarry-dump complex and the Barsukivskyi sand pit, it was concluded that the processes of soil formation began in the substrate of the Andriykovetskyi quarry-dump complex, since the composition of organic matter is greater here.

Effect of Salinity and Substrate on the Emergence and Growth of Propagules of the Mangrove Species Rhizophora racemosa in the Sassandra-Dagbego Ramsar Complex, Côte d’Ivoire

This study aimed to evaluate the behaviour of seeded propagules of Rhirophora racemosa (R. racemosa) on different substrates and under different salinity levels. Three substrates including sand, mud and a mixture of the two were tested together with tree salinity levels (low 5%, moderate 10% and high 25%). R. racemosa seedlings were more likely to emerge and grow under moderate and low salinity conditions. The propagules had significant early growth in mud compared to sand and mud-sand mixture. The combined effect of salt and substrate influenced significantly propagules performance in nursery (p<0.001). High propagules emergence and growth were observed in the combination mud and salt treatments as compared to sand and san-mud mixture substrates. These results provide valuable information for the management and restoration of mangroves, highlighting the optimal environmental conditions for the successful regeneration of this species.

Seasonal dynamics and habitat preferences of juvenile fish assemblages in the Wanquan Estuary, South China: Implications for conservation and management

Tropical estuaries encompass diverse habitats, which are crucial for supporting juvenile fish by providing nurseries, refuges, and migration routes. In the present study, we investigated the seasonal and spatial dynamics of juvenile fish assemblages in the Wanquan Estuary, Hainan Island, China, examining variations during the wet and dry seasons across four types of habitats. Our research aimed to test the hypotheses: (1) the wet season supports a greater abundance and species richness of juvenile fish compared to the dry season, and (2) juvenile fish showed varying habitat preferences across seasons. We recorded a total of 3617 individuals belonging to 33 families, 50 genera, and 78 taxa. Our findings revealed significant seasonal fluctuations in the assemblage structure, with peak abundance during the wet season in August, primarily consisting of diadromous species. A notable shift towards marine species was observed in March. Spatially, juvenile fish exhibited significant habitat preferences, with a strong preference for sand substrates for most species. Contrary to common expectations, mangrove fringe habitats were not identified as the primary nursery grounds for juvenile fish. Instead, our study highlights the importance of habitat diversity and connectivity in enhancing nursery functions. Water temperature and salinity were the key drivers influencing the seasonal and temporal patterns of juvenile fish assemblages in the Wanquan River estuary The pronounced temporal dynamics of these assemblages, driven by seasonal environmental alterations affecting water variations and habitat connectivity, were more significant than spatial differences. The findings emphasize the need for focused connectivity of various habitats to support the conservation of diverse fish communities in tropical estuarine ecosystems.

Influence of Vermicompost on the Concentration of Exogenous Indole-3-Acetic Acid and Its Effect on the Development of Tomato Plants (Lycopersicum esculentum L.)

Indole-3-acetic acid (IAA) concentration is directly proportional to the amount of vermicompost (VC) added to sand substrates. The objectives of this work were to establish the effect of the amount of VC in sand substrates on the concentration of IAA and to determine its influence on tomato plants. Sand substrates with VC percentages (0, 20, 40, and 50%) were placed in pots; in each one, the concentration of IAA was determined at the beginning and the end (after supporting tomato plants), and its bacterial load was determined. In tomato plants, some vegetative and yield components were measured. The results show that by adding 1 kg of VC in a sand-based substrate, the concentration of exogenous IAA increases by 0.0470 and 0.0642 mg g−1 (at the beginning and the end, respectively). This increase was reflected in the development of the plants; for example, their roots demonstrated their maximum development (370.20 cm−3) when the amount of VC in the substrate was 3.95 kg. Therefore, the amount of VC used in the preparation of substrates influences the concentration of IAA in them, which is reflected in the development of tomato plants.

The effect of temperature and sand substrate in tanks on the growth and survival of the warty sea cucumber Neostichopus grammatus

ABSTRACT Water temperature and the presence of sand substrate are considered critical environmental factors affecting the growth of cultured sea cucumbers. This study investigated the effects of water temperatures and the presence or absence of sand substrate in tanks on the growth of N. grammatus fed an equal ration of abalone waste for eight weeks. Sea cucumbers with a mean weight of 8.34 g were used for the study. The treatments used in the study were Ambient water temperature + sand (A + S), Ambient water temperature without sand (A-S), Cold water temperature + sand (C + S), and Cold-water temperature without sand (C–S). The cold/constant water temperature was 16°C and was representative of winter conditions while the ambient/fluctuating water temperature fluctuated between 16.4 and 18.7 °C and was representative of spring conditions. At the end of the study, the sea cucumbers in A + S and C + S treatment groups exhibited an overall weight increase of 21.08% and 6.18%, respectively. The sea cucumbers reared in ambient water temperature exhibited significantly higher mean weight than those reared in cold water (F 1, 66 = 5.69; p = 0.02), and sea cucumbers reared with sand substrate had significantly higher mean weight compared to those without sand substrate (F 1,66 = 19.06; p = <0.001). This study has shown that growth rates of N. grammatus in tanks were higher in ambient temperatures and that stress was reduced in the presence of sand, a habitat that mimics its natural environment. This implies that sand substrate may be necessary for the farming of N. grammatus.

Habitat Characteristics and Morphology of Chlorophyta (Order Bryopsidales) on the Intertidal of Pandanan Hamlet, West Sekotong

Bryopsidales order macroalgae can be found on various substrates in marine waters. The Bryopsidales order has a morphological form that is shaped like a filament or shaped like a leaf and has pigments like land plants. The study aims to determine the habitat characteristics and morphology of the Bryopsidales order on the coast of Pandanan Hamlet. Sampling was carried out using the line transect method and 1x1 meter quadrant. A total of 5 transect lines were stretched from the shoreline to the point where macroalgae were found. Each transect is placed in quadrants every 20 meters in a zigzag manner. The Bryopsidales order found consisted of 13 species, 3 families and 4 genera growing in habitats with substrates of loamy sand, loam, sand, and sandy loam, rock, dead coral, coral fragments, and live coral. There are 3 types of holdfast were found, namely bulbous, fibrous, and sprawling growers. There are also three blade shapes in this order, namely creeping blades in the Caulerpaceae family, segmented blades in the Halimedaceae family, and blades that are neither creeping nor segmented that resemble sponges in the Codiaceae family.