Saline Ponds Research Articles

Paddy straw biochar amended sediment enhances pond productivity, growth and physiological profile of Penaeus vannamei cultured in inland saline nursery ponds.

The growing interest in commercial Inland saline aquaculture has taken momentum across the globe due to the available technologies for aquaculture and the abundant resources of saline groundwater. However, the critical problems in inland saline ponds are degraded soil and imbalanced or deficient nutrients. To address these issues, a 75-day experiment was conducted to explore the effects of Paddy Straw Biochar (PSB) as a sediment amendment on sediment quality, water characteristics, growth parameters, and the well-being of Penaeus vannamei reared in inland saline environments. PSB was applied to the nursery ponds at 1 ton/hectare (Treatment, T1) and 2 ton/hectare (Treatment, T2). The findings of water quality parameters showed a significant increase in K+ and Mg++ with a decrease in ammonia-N levels in biochar-applied ponds. Similarly, the addition of biochar to ponds (T2) resulted in improved sediment characteristics with enhanced water holding capacity (24.75%), increased soil organic carbon content (77.94%), pH levels (0.37 units), cation exchange capacity (43.15%), available potassium (16.3%), and lower bulk density (12.61%) compared to ponds subjected to control conditions at the end of the experiment. Over the experiment, improvements in sediment and water quality parameters followed the T2 > T1 > control trend. Growth characteristics showed a significant rise in the percentage of weight gain (12.398 ± 0.12), SGR (11.80 ± 0.01% day-1) and PER (2.39 ± 0.01) with reduced FCR (1.19 ± 0.00) in biochar-treated ponds (T2), followed by T1 and control. The digestive enzyme activity (amylase) and metabolic enzymes like hepatopancreatic alanine aminotransferase (ALT) and muscle ALT activities were significantly higher in shrimps raised in the biochar-applied ponds. On the other hand, the oxidative stress enzyme superoxide dismutase (SOD) in gills, muscles, and hepatopancreas (HP) exhibited lower values, suggesting reduced oxidative stress due to the biochar amendment of the pond sediment. Overall, the study recommends incorporating PSB at a rate of 2 t/ha into nursery pond sediment to enhance water quality, physiological status, and the growth of P. vannamei juveniles. Moreover, this approach improves soil and water characteristics in saline soils, making it an effective culture practice in degraded environments.

Influence of Water Quality and Phytoplankton Community on the Growth of Litopenaeus vannamei in Low-Salinity Semi-Mass Circular Ponds

This study examines the dynamics of vannamei shrimp (Litopenaeus vannamei) cultivation in low salinity aquaculture systems, focusing on water quality parameters, plankton diversity, and shrimp growth rates. Vannamei shrimp are favored in aquaculture due to their disease resistance, rapid growth, and high survival rates. Key water quality parameters, including dissolved oxygen (DO), temperature, light intensity, pH, and salinity, were monitored over a 30-day period in low salinity ponds. The results showed significant fluctuations in these parameters, influencing shrimp health and growth. DO levels varied from 5.8 to 8.39 ppm in the morning and from 5.14 to 7.8 ppm in the afternoon. Water temperature ranged from 27.3°C to 32.3°C, light intensity from 3,170 to 66,300 lux, pH from 7.72 to 8.73, and salinity from 5 to 6 ppt. Plankton diversity and density, including species like Microcystis, Cyclotella, and Rhizosolenia, were also assessed, highlighting their role in the aquatic ecosystem. The specific growth rate (SGR) of the shrimp was calculated, showing a favorable growth rate of 2.32% per day. These findings indicate that maintaining stable water quality and diverse plankton populations is crucial for optimizing shrimp growth in low salinity aquaculture systems. This research provides valuable insights into the environmental conditions necessary for successful vannamei shrimp cultivation, emphasizing the importance of regular monitoring and management to ensure sustainable aquaculture

Pedological features of a sustainable halophyte wetland: El Hito saline pond (Central Spain)

AbstractIn semi‐arid Mediterranean regions, particularly in some wetland soils, salinity is thought to be an indicator of low‐quality soils. In this study, a characterization is presented of the soils surrounding El Hito saline pond (Castilla La Mancha, Central Spain), an ecological halophyte niche within a natural semi‐arid steppe land. The main aim is to classify the salt‐affected soils and their morphology, genesis, and physico‐chemical properties. Four soil profiles were opened with a backhoe machine for sampling and subsequent description on the basis of their pedogenetic morphology. Systematic surface sampling was also performed. Standard methods were followed to measure the soil properties of 27 samples. Overall electrical conductivity (EC) and pH levels of the wetland were mapped (using ArcGIS 3.1.3). Soil salinity at elevated levels was detected, inhibiting plant uptake of water and nutrients. Distinct sub‐areas of extreme elevated surface salinity providing specialized plant habitats and poor soil structure were observed, as well as a mainly whitened‐yellowish‐greenish soil colour due to salt accumulation and poor drainage. The soils also showed alkaline pH values. In most samples, the pH was over 8.5, and EC was higher than 4 (dS m−1), and in several samples higher than 20 (dS m−1). A low sodium (Na) content was detected in the saturation extract where magnesium (Mg+) was the dominant soluble cation, followed by both calcium (Ca+) and sodium (Na+), and then potassium (K+), present in lower proportions. Sulphate (SO42−) and then chloride (Cl−) anions were dominant, although carbon trioxide, (CO3−) and carbonate (CO32−) anions were also present. The percentages of organic carbon (C) were very low, while total nitrogen (TN) and available phosphorus (P) were higher in the upper horizons, suggesting a degree of eutrophication. The present work will increase the existing knowledge about the role of El Hito saline pond, that play a vital ecological role in the broader biosphere, providing new suggestions to readers on how this knowledge can be used to improve these types of ecosystems. In particular, the agricultural pesticides and fertilizers continuously damage the soil fertility as evidenced by the high content of soluble phosphorus found in some points of the Hito saline pond.

An Ecological Overview of Halophytes and Salt-Affected Soils at El Hito Saline Pond (Central Spain): Baseline Study for Future Conservation–Rehabilitation Measures

In an attempt to boost the potential ecological viability of wetlands, this study aimed to discover the relationship between soil salinity and vegetation composition in a quasi-pristine saline pond, “El Hito Lagoon”. This wetland is situated in the largest continuous natural semi-arid steppe land of western Europe (specifically in Castilla La Mancha, Central Spain). Several soil profiles and a series of surface samples (0–10 cm) extracted from a systematic network throughout the saline pond were described, sampled, and analyzed. The most significant results included the detection of elevated levels of soil salinity, with distinctive sub-areas of extreme elevated surface salinity where the pH reading peaked at 9.89 and the electrical conductivity was higher than 40 (dS/m). The very high content of total available P displayed quite an irregular scatter within the soil profile. Specifically, the range oscillated between 8.57 mg/kg and 388.1 mg/kg, several samples having values greater than 100 mg/kg. An aspect that the abundant presence of Salsola soda, a plant frequently found growing in nutrient-rich wetlands, was able to confirm.

Enhancement of aquaculture performance of cobia, Rachycentron canadum (Linnaeus 1766): A review

Cobia, Rachycentron canadum, is a marine fish with recognized potential for aquaculture due to its fast growth rate, high fecundity, disease resistance, and quality flesh. However, much progress has been made to overcome problems associated with aspects of cobia production, including broodstock management, fingerling production, larval-rearing, grow-out, and disease management, though, an effort is needed to ensure its sustainability. Broodstock conditioning protocols for continuous spawning as well as induced spawning via hormonal injection resulted in all-year-round seed production in cobia, but detailed information on the cost-effective dosages of various spawning hormones for maximum fecundity and larval survival needs to be investigated. Selective breeding, the application of genetics in trait selection, and the use of molecular markers could produce more viable strains to mitigate high mortality, particularly in colder climates. In addition, considering the fact cobia are carnivorous fish with a high protein requirement, it will be necessary to investigate fishmeal alternatives to reduce feeding costs. Low salinity pond culture may become a reality in the future if the cobia metabolism-physiology of nutrition at various levels of salinity is well understood. The present paper provides information on some of the options for optimizing the aquaculture performance of Rachycentron canadum.

Effect of pH and Light Intensity on the Growth of Dunaliella Salina


 
 
 Dunaliella salina is a unicellular halophilic green alga dominantly found in salt lakes, and high saline ponds in slatterns all over the world. A rigid cell wall is absent in D. salina while the cells are covered by mucous materials that are enclosed by a thin elastic plasma membrane. This species has both environmental and economic validity as they are capable of producing β–carotene during photosynthesis. Synthesis of β–carotene in D. salina is a function of environmental factors, and thus, the present study was designed to study the effect of pH of the medium and light intensity on the growth of D. salina. The Algae sample was collected from a crystalizing pond of Hambantota Saltern, Sri Lanka, and a monoculture was maintained under suitable laboratory conditions. The seawater sample with pH 7.66 was used to prepare a series of pH using sodium carbonate anhydrous. These cultures were exposed to a series of pH (7.66, 8.0, 8.50, and 9.0) at two light intensities (885 lux and 200 lux). All experimental setups were maintained at 25oC with the photoperiod of 12h light and 12h dark. Four replicates of each pH medium were arranged into a 4×4 setup of flasks for each light intensity and the experiment was conducted for four weeks. At the end of the fourth week, the pH level of all flasks ranged from 8.27 to 8.53 due to the self-adjustment of the pH level in the culture medium in parallel to algal growth. The maximum growth was reflected by the highest absorbance of 1.46 at 750 nm. Taken together, our findings revealed that the optimum pH range and light intensity for culturing D. salina is 8.27-8.53 and 885 lux respectively. This study recommends further research on culturing of D. salina for extracting the bioproduct of β -carotene at various light intensity levels.
 Keywords: Cell density, β –carotene, Light intensity, Self-adjusted
 
 

Production system and challenges of saline aquaculture in Punjab and Sindh provinces of Pakistan

IntroductionLack of data about saline aquaculture in Pakistan has curtailed informed policy and investment decision making resulting in undervaluation of and underinvestment in the sector. Therefore, saline aquaculture in Pakistan is today an underdeveloped sector despite its potential as an alternative livelihood for the country's rural farmers. This study represents one of the initial exploratory investigations into saline aquaculture systems in Pakistan, aiming to comprehend the existing sectoral landscape, production challenges, post-harvest constraints, and the associated capacity and investment needs.MethodsThe study employed purposive sampling to survey 121 low-income saline aquaculture farmers across five districts of Southern Punjab and Sindh provinces. The analysis was carried out using descriptive statistics.ResultsThe results revealed that the saline aquaculture sector is predominantly male-centric, with agricultural land utilized for both agriculture and aquaculture purposes. Ponds, which usually serve multiple functions, focus primarily on carp production, but adherence to good management practices remains limited. Farmers face various challenges, including the high costs of feed and seeds, freshwater scarcity, inadequate technical knowledge, and marketing issues.Discussion and conclusionThis study serves as a foundational assessment, addressing data and information gaps crucial for supporting the sustainable development of saline aquaculture in Pakistan. To facilitate such development, the study recommends initiating programs to strengthen technical skills in saline aquaculture, together with the establishment of hatcheries and breeding stations for saline-tolerant species, aiming to reduce dependence on freshwater species in saline pond environments.

Salinity-controlled distribution of prokaryotic communities in the Arctic sea-ice melt ponds.

The thawing of snow and sea ice produces distinctive melt ponds on the surface of the Arctic sea ice, which covers a significant portion of the surface sea ice during summer. Melt-pond salinity impacts heat transfer to the ice below and the melting rate. It is widely known that melt ponds play a significant role in heat fluxes, ice-albedo feedback, and sea-ice energy balance. However, not much attention has been given to the fact that melt ponds also serve as a unique microbial ecosystem where microbial production begins as soon as they are formed. Here, we investigated the role of melt pond salinity in controlling the diversity and distribution of prokaryotic communities using culture-dependent and -independent approaches. The 16S rRNA gene amplicon based next generation sequencing analysis retrieved a total of 14 bacterial phyla, consisting of 146 genera, in addition to two archaeal phyla. Further, the culture-dependent approaches of the study allowed for the isolation and identification of twenty-four bacterial genera in pure culture. Flavobacterium, Candidatus_Aquiluna, SAR11 clade, Polaribacter, Glaciecola, and Nonlabens were the dominant genera observed in the amplicon analysis. Whereas Actimicrobium, Rhodoglobus, Flavobacterium, and Pseudomonas were dominated in the culturable fraction. Our results also demonstrated that salinity, chlorophyll a, and dissolved organic carbon were the significant environmental variables controlling the prokaryotic community distribution in melt ponds. A significant community shift was observed in melt ponds when the salinity changed with the progression of melting and deepening of ponds. Different communities were found to be dominant in melt ponds with different salinity ranges. It was also observed that melt pond prokaryotic communities significantly differed from the surface ocean microbial community. Our observations suggest that complex prokaryotic communities develop in melt ponds immediately after its formation using dissolved organic carbon generated through primary production in the oligotrophic water.

Comunidades de aves acuáticas de la laguna Mar Chiquita (Córdoba, Argentina)

Mar Chiquita is a large inland brackish water body of about 2,000 km2, with a salinity of around 100 °/oo. Its aquatic bird communities were studied throughout a year in three study areas, representative of the main habitat types found in the región. We collected information on species composition and abundance, as well as foraging behaviour, feeding site utilization and stomach contents.
 In total we recorded 55 species. The richest community (both in number o f species and individuals) was found around the Rio Segundo estuary, while the less diverse corresponde to saline ponds near the coast. Summer migrant species (long range neartic migrants) included nine species and accounted for the 21% of the observed birds. Winter visitors included five species and made up 1% of bird numbers. Ecological guilds species composition and patterns of resource utilization are analyzed. They closely resemble those of marine estuarine and intertidal conditions. At present, the main adverse factors for the preservation of the local aviiauna are linked with planned stream regime modifications through dam building, and contamination due to industrialdevelopment along tributary rivers.

Geomicrobiology of the Rincon de Parangueo maar crater: Exploring the link between an evolving extreme environment and its potential metabolic diversity

Abstract Rincon de Parangueo (RP) is a Quaternary maar crater located in the Michoacan‐Guanajuato Volcanic Field in central Mexico. Like other volcanic craters in the region, the central part was occupied by an endorheic lacustrine system. As a consequence of extensive groundwater extraction, the perennial lake started a gradual desiccation process and now the remnant ponds host a highly saline–alkaline ecosystem. The stratigraphic record indicates an exceptional and long‐term sedimentation of carbonate microbialites. Previous studies based on the 16S rRNA gene have shown that microbial communities have a widespread presence in the crater at the microbialites, the remaining saline ponds, superficial soils and below the surface. To understand the possible role of the microbial communities that generate these biogeological structures, novel analytical methods to resolve the amplicon datasets and their microbial metabolic potential were used. We describe in detail the relationship between the microbial communities, the evolution of physicochemical parameters, and carbonate morphology, in four micro‐environments. A 16S rRNA gene sequencing dataset from previous publications was re‐analysed using an ASV‐based bioinformatic pipeline to identify new insights into the microbial assemblage. Finally, a taxon‐based metabolic profile was used to predict the potential metabolic contribution of the prokaryotic community. Results indicated a refinement in terms of community composition using the ASV‐based bioinformatic methods. Functional profiling through 16S rRNA gene‐based analysis suggested metabolisms associated with carbonate precipitation, indicating a broad potential for microbially mediated carbonate precipitation (e.g., carbon fixation and photosynthesis). The possibility of biogenic methane gas production by methanogenic microorganisms was recognised, supporting the estimated flow of methane on the surface soils. The lacustrine evolution over the last years and the extreme physicochemical characteristics of RP have an impact on the microbial community structure. Prokaryotic community and metabolic potential results from RP coincide with the diversity and abundance of microbial communities and functional metabolisms reported from other microbialite‐forming lakes along the Trans Mexican Volcanic Belt. The identification of important possible phylotypes involved in carbonate precipitation might be an important factor in considering RP microbialites as active calcifying entities. These findings provide novel insights into the potential key role of metabolic pathways driving the process of carbonate precipitation inside RP and evidence of its importance as a microbial biodiversity hotspot in Mexico.

Bacterial Strains from Saline Environment Modulate the Expression of Saline Stress-Responsive Genes in Pepper (Capsicum annuum).

Salinity stress is one of the most important problems in crop productivity. Plant growth-promoting bacteria (PGPB) can also confer stress tolerance in plants under saline soil conditions. In a previous work, it was reported that bacteria strains isolated from hypersaline sites mitigated salt stress in chili pepper (Capsicum annuum var. Caballero) plants and promoted plant growth in some cases. The aim of this study was to evaluate the modulation of gene expression in C. annuum plants by bacteria strains isolated from saline environments. Two bacteria strains from high salinity ponds in Guerrero Negro, BCS, Mexico (Bacillus sp. strain 32 and Staphylococcus sp. strain 155) and Azospirillum brasilense Cd (DSM 1843) were used. Significant improvement in fresh weight yield (stem (28%), root (128.9%), and leaves (20%)) was observed in plants inoculated with Bacillus sp. strain 32. qPCR analysis showed that both strains modulated the expression of stress-responsive genes (MYB, ETR1, JAR1, WRKY, and LOX2) as well as heat shock factors and protein genes (CahsfA2, CahsfA3, CahsfB3a, CaDNaJ02, and CaDNaJ04). Finally, the expression levels of genes related to early salt stress and ISR showed differences in plants with dual treatment (bacteria-inoculated and salt-stressed) compared to plants with simple salinity stress. This work confirmed the differential modification of the transcriptional levels of genes observed in plants inoculated with bacteria under salinity stress.

Long-term trends of salinity in coastal wetlands: Effects of climate, extreme weather events, and sea water level

Coastal freshwater ecosystems play major roles as reservoirs of biodiversity and provide many ecosystem services and protection from extreme weather events. While they are of particular importance worldwide, they are affected by a large variety of anthropogenic threats, among which salinization has been less studied, particularly regarding large temporal and spatial data sets based on real case scenarios, while salinity can impact biodiversity and ecosystem functioning. In this study, we investigated the variations of salinity across long-term (1996–2020) and seasonal (monthly records) temporal scales and spatial (varying distance to the coastline) scales in water bodies of two typical temperate coastal wetlands situated on the Atlantic coast of France. We complemented our analyses with models of sea water levels computed at both sites across 2000–2020. Our detailed data set allowed for highlighting that salinity in ponds varied seasonally (higher during summer, due to decreased precipitation and higher temperature), but also spatially (higher closer to the seashore, which pattern increased through time). Over the long term, decreased precipitation but not increased temperature induced increasing salinity. We also highlighted contrasted long-term patterns of salinity changes on these two coastal wetlands, with one site were salinity decreased over time linked to the responses to marine flood, allowing to document the temporal dynamics of salinity following a massive intrusion of sea water. Complementarily, at both sites, water levels at high tides increased through time, a pattern which can induce additional salinization. To our knowledge, our study is the first to investigate long-term changes in salinity in coastal wetlands through natural processes (e.g. seaspray, seasonal variations) and ongoing climate perturbations (e.g. marine surges linked to extreme weather events, increased temperature and decreased precipitations).

Multidisciplinary characterization of the new species Copemetopus mystakophoros and its symbionts with a proposal for the new class Copemetopea (Alveolata: Ciliophora)

Abstract The history of the genus Copemetopus is tortuous and studded with several misattributions. It was erected by Villeneuve-Brachon in 1940 after the discovery of Copemetopus subsalsus in saline ponds along the French coast of the Mediterranean Sea near Sète and associated with the class Heterotrichea in the family Metopidae, close to Bryometopus. After a long series of systematic revisions, it is now clear that Copemetopus is not a heterotrich and that it falls in the subphylum Intramacronucleata. Nevertheless, a lot more work is needed to fix the complex taxonomic status of the genus, which lacks a precise taxonomic collocation (it is presently referred to as incertae sedis). In the present study focused on a multidisciplinary and detailed description of a new species, of the genus, Copemetopus mystakophoros sp. nov., we also propose the erection of the new class, Copemetopea cl. nov. After careful literature and data revision, we believe that members of Copemetopus require a higher-ranked taxon in the phylum Ciliophora, given their molecular and morphological peculiarities.

Pengembangan Sistem Monitoring Tingkat Salinitas Air Pada Tambak Rumput Laut Berbasis Website

The level of salinity in water quality is one of the determining factors in the success of seaweed aquaculture production. The purpose of this study was to develop a website-based monitoring system for the level of water salinity in seaweed ponds. Monitoring system development is carried out by designing and developing an integrated website. Measurement of water salinity in ponds uses a sensor with a microcontroller connected via the internet network so that monitoring can be carried out without the need to go to the pond location. This type of research is development (Research and Development) which refers to the waterfall model (Planning, Analysis, Design, Implementation, Maintenance). The results of the research show that website development as a monitoring system has been successfully developed. There are four pages that can be displayed on the website for monitoring seaweed pond water salinity, namely the login page, homepage, viewing data, and monitoring water salinity. This research is expected to provide an overview in monitoring water quality in increasing the productivity of seaweed cultivation.

Effects of acute salinity stress on the survival and haemolymph biochemistry of juvenile tropical rock lobster, Panulirus ornatus, at different moult stages

The tropical rock lobster, Panulirus ornatus, is emerging as an important species for onshore aquaculture development, with commercial grow out of lobsters from the juvenile to harvest phase likely to be conducted in outdoor raceways or pond culture systems in tropical regions of Australia. In these areas, climate has a large impact on the prevailing environmental conditions, including torrential rain and extended periods of heat waves, which can rapidly reduce or increase pond salinity for hours to weeks. The impacts of moulting on the salinity tolerance of P. ornatus survival and physiology are unknown. This study investigated the survival (LC50) and haemolymph biochemistry of P. ornatus juveniles when acutely exposed for 48 h to different salinities (10, 15, 20, 25, 30, 34, 40, 45, 50, 55, and 60 ppt) at three stages of the moult cycle (post-, inter- and pre-moult). Moult stage significantly impacted the survival of lobsters at low salinity (<34 ppt), which ranged from LC5048 = 12.5 ppt for post-moult lobster to LC5048 = 20.0 for pre-moult. There was no significant effect of moult stage on high salinity (>34 ppt) tolerance of lobsters which ranged from LC5048 = 50.5–54.5 ppt. Haemolymph osmolarity showed inter-moult lobsters to be weak hyper-regulators, with post- and pre-moult being hyper-osmoconfromers. Moult-stage significantly affected haemolymph oxyhaemocyanin and protein concentration, with pre-moults having the highest values and post-moult the lowest, with no impact of salinity treatments. At 50, and 55 ppt, oxyhaemocyanin was significantly elevated above total protein concentration compared to 34 ppt with no effect of the moult stage. While at 55 ppt, superoxide dismutase (SOD) activity was significantly lower compared to 25, 40, 45, and 50 ppt with no effect of moult stage. Our results suggest a salinity tolerance range between 20 and 40 ppt, beyond this, lobsters experience oxidative stress due to the breakdown of osmoregulation. This study provides an improved understanding of the survival and physiological impacts of acute salinity change on P. ornatus that is essential for optimising productivity protocols for the onshore aquaculture of the species.

An Appraisal of Heavy Metal Distribution in Surface Water and Groundwater in the Vicinity of a Salt Mine

Water quality is a big concern for the humankind as it is the most important natural resource. The quality of water is affected by anthropogenic activities carried which could render it unsuitable for human consumption. The present study assessed heavy metal distribution and toxicity in surface and groundwater resources of an area characterized by salt mining from brine ponds. Samples were analyzed for pH, electrical conductivity (EC) elemental compositions of: Ba, Mn, Fe, Cu, Sr, and Zn to assess their spatial distribution, sources, variability, toxicity and possible health risks. Median concentrations of Ba, Mn, Fe, Cu, Sr, and Zn in surface water was: 0.28, 3.63, 2.23, 0.03, 0.14 and 0.05 respectively while for groundwater, median concentration was: 0.65, 0.20, 1.16, 0.03, 0.83 and 0.11 respectively. In terms of suitability, concentrations of Mn, Fe and Sr in surface water, and that of Sr, in groundwater raises some quality concerns since they are all present in concentrations above the permissible limits for drinking water. Results of Corelation and Principal Component Analyses showed that source and mobility of these metals is linked to both geogenic (host rock weathering) and anthropogenic activities mainly associated with salt mining and processing in the region of a saline pond. Spatial distribution of concentration of these metals also shows higher concentrations in the immediate region of the salt mine especially in groundwater.

Reproductive performance of captive-reared Indian white shrimp, Penaeus indicus, broodstocks over two generations

Closing the complex life cycle of closed thelycum shrimp in captivity is one of the fundamental challenges in breeding programs. In the present study, we investigated the sexual maturity, broodstock development, and spawning performance of two generations of captive-reared Indian white shrimp, Penaeus indicus, over 36 months originated from a single stock of wild brooders. The post larvae (GN-1) produced from wild P. indicus (G0) and P.L. (GN-2) produced from captive-reared (GN-1) broodstocks were nursery (1000 PL m-3) and grow-out (12 shrimp m-2) reared, and subsequently raised in broodstock ponds (1 shrimp m-2). The annual salinity and photoperiod in broodstock ponds varied between 20 to 36 ppt, and 11.2 -12.5 L and 11.5-12.8 D hours, respectively. The light intensity varied between 91 ± 6 lux at dusk to 75,358 ± 1719 lux at noon. The size at first impregnation or mating was 16.45 ± 1.7 g (132 DOC) and 17.62 ± 1.9 g (90 DOC), respectively, in GN-1 and GN-2 females. By 220 DOC, 25% of the GN-1 females initiated gonad development, whereas 55% of the GN-2 females recorded developing ovaries or were in stage II at 150 DOC. The broodstock attained an average final body weight of 38.85 ± 1.5 g (GN-1) and 42.65 ± 1.8 g (GN-2) by 360 DOC. The highest (p&amp;lt;0.01) eggs per gram body weight (5137 ± 303 eggs g-1) and hatchability, H (83 ± 0.7%), was recorded in wild broodstocks (G0) followed by GN-2 (1,715 ± 162 eggs g-1; H: 69 ± 2%) and GN-1 (1,476 ± 151 eggs g-1; H: 75 ± 1%). However, captive-reared broodstock had better survival (89-92%) than wild broodstocks (71 ± 0.8%). Further, indoor maturation trial (21 days) using ablated broodstocks (GN-1) revealed 79% of the impregnated broodstocks undergo molting, resulting in the loss of sperm pack and subsequent reduction in mating efficacy to 29%. The average sperm count and percentage of normal sperm also recorded (p&amp;lt;0.05) reduction during the maturation cycle. The data generated in the present investigation can form the baseline information for developing the breeding strategy for the genetic improvement of Indian white shrimp in India.

Environmental changes associated with drying climate are expected to affect functional groups of pro- and microeukaryotes differently in temporary saline waters

Temporary ponds are among the most sensitive aquatic habitats to climate change. Their microbial communities have crucial roles in food webs and biogeochemical cycling, yet how their communities are assembled along environmental gradients is still understudied. This study aimed to reveal the environmental drivers of diversity (OTU-based richness, evenness, and phylogenetic diversity) and community composition from a network of saline temporary ponds, soda pans, in two consecutive spring seasons characterized by contrasting weather conditions. We used DNA-based molecular methods to investigate microbial community composition. We tested the effect of environmental variables on the diversity of prokaryotic (Bacteria, Cyanobacteria) and microeukaryotic functional groups (ciliates, heterotrophic flagellates and nanoflagellates, fungi, phytoplankton) within and across the years. Conductivity and the concentration of total suspended solids and phosphorus were the most important environmental variables affecting diversity patterns in all functional groups. Environmental conditions were harsher and they also had a stronger impact on community composition in the dry spring. Our results imply that these conditions, which are becoming more frequent with climate change, have a negative effect on microbial diversity in temporary saline ponds. This eventually might translate into community-level shifts across trophic groups with changing local conditions with implications for ecosystem functioning.

BIOTECHNOLOGICAL STUDIES ON SALINITY-TOLERANT MICROORGANISMS.

Halophilic and halo-tolerant bacteria are micro-organisms that living in hyper saline environments. They have many potential in several fields in life such as Industry and agriculture. In this study a total of 17 isolates were obtained from the four saline ponds of Qarun Lake on Nutrient Agar (NA) medium prepared using ponds' water. The 16S rRNA analysis showed that our isolates affiliated with four groups, Firmicutes (47.06% of the isolates) that include family Bacillaceae with six different genera including Bacillus, Halobacillus, Lentibacillus, Oceanobacillus, Thalassobacillus and Virgibacillus, Gammaproteobacteria (35.29% of the isolates) including two genera Halomonas and Salinivibrio, two within Bacteriodetes group (11.76% of the isolates) and one of Alphaproteobacteria (5.88%). Firmicutes seems to be the more dominant group, including microorganisms of various genera, especially Bacillus (37.5%) followed by Halobacillus, Oceanobacillus, Lentibacillus and Virgibacillus (12.5% for each genera). 52.94% of isolates were gram negative, 35.29% were gram positive and 11.76% were gram variable. All isolates were catalase producers and motile. Halotolerance assay observed that only two isolates (11.76 %) were able to grow on the absence of salt and considered as halotolerant, while fifteen isolates (88.24%) were able to grow on NA media with different salt concentrations and considered as halophilic bacteria. Among them, thirteen isolates (76.47%) were able to grow on NA media with 7% NaCL. All isolates grew on NA with 12.5% NaCl; nine iso-lates (52.94%) were able to grow on NA media with 20% salinity, while three isolates (17.65%) appeared on NA media with salt concentration of 22% and considered extremely halophilic bacteria. All isolates were tested for plant growth promoting factors. The results showed that all isolates can produce IAA, while 47.06% of isolates can fix Nitrogen and 47.06 % have ability for phosphate solubilization. Concerning hydrolytic enzymes activi-ties of the isolates, it was found that 58.82% and 76.47% of isolates pro-duced lipase using olive oil and tween80 as a substrate respectively. It was also found that 47.06% of isolates showed ability for esterase production and same percentage for casease production. Gelatinase was excereted by 58.82%, while chitinase was produced by 70.59% of isolates. Five isolates were screened for biosurfactants and other bioactive compounds production. These isolates namly as QSLA1, QSLA7, QSLA14, QSLA16 and QSLA17 which were similar to, Halomonas sp.RS-17, Salinivibrio sp. pr6, Lentibacillus sp.strain BCHS25, Uncultured bacterium clone QAMU23 and Bacillus sp.strain6 in the GenBank database, respectively. Among them two isolates QSLA16 and QSLA17 had NRPs genes encoding for lipopeptide biosurfactants synthetase enzymes and HPLC analysis confirmed presence of different biosurfactants such as, surfactin, fengycin and mycosubtilin. The culture of the two isolates, QSLA1and QSLA7 were analysed by Gas chromatography–mass spectrometry (GC-MS) and showed ability for production of antifungal, antimicrobial and antitumer metabolites such as Desulphosinigrin, Undeca-2,4,6,8,10-pentaenal, 11-(2-furyl)-, oxime and Strychane, 1-acetyl-20à-hydroxy-16-methylene. Accordingly, QSLA1 had in vitro antibacterial activity against Salmonella typhi and Acinetobacter baumannii. Whereas, QSLA16 was able to inhibit the growth of bacterial pathogens Staphylococcus aureus, Klebsiella pneumonia and Salmonella typhi in contaminated salty whey. In this regard, QSLA1 showed in vitro antifungal activity against Alternaria solani and Fusarium oxysporium f.sp. lycopersici, and had in vivo a siginificant effect on the growth of Fusarium oxysporium f.sp. lycopersici infecting tomato seedlings compared to control and therefore can be used among biological control systems under saline conditions

Indonesia's Blue Economy Potential: Salt Pond in Nagekeo, East Nusa Tenggara

Allegedly, based on the diversity of the maritime by Indonesia, our country has a very potential wealth of marine resources. These resources can be utilized for its used as blue econommy approach. This country’s marine resources that can be utilized as a national economic potential is a salt industry. With the wealth of the saline water that we have, Indonesia is still importing salt because there is an imbalance between demand and domestic production. The purpose of this journal is to find out the potential for briny ponds in Indonesia to be used to reduce the dependence on national imports. To handle this problem, there are several efforts to maximize our national productions of saline pond in Nagekeo District, East Nusa Tenggara (Nusa Tenggara Timur). Along with the modernization and technology, there is several branches of innovation and technology to increase the effectiveness of Indonesia’s Sea Salt Industry such as Geomembrane Prism House, Vertical Axis Mill Pump, and the Smart House Salt Maker (SHASA). By adopting these technologies, it is expected that the production of marine salt farmers will be able to severely reduce salt imports and make Indonesia a successful and independent maritime country.