Salt Ponds Research Articles

Extreme waves in the British Virgin Islands during the last centuries before 1500 CE

Extraordinary marine inundation scattered clasts southward on the island of Anegada, 120 km south of the Puerto Rico Trench, sometime between 1200 and 1480 calibrated years (cal yr) CE. Many of these clasts were likely derived from a fringing reef and from the sandy flat that separates the reef from the island’s north shore. The scattered clasts include no fewer than 200 coral boulders, mapped herein for the first time and mainly found hundreds of meters inland. Many of these are complete colonies of the brain coral Diploria strigosa . Other coral species represented include Orbicella (formerly Montastraea ) annu­laris , Porites astreoides , and Acropora palmata . Associated bioclastic carbonate sand locally contains articulated cobble-size valves of the lucine Codakia orbicularis and entire conch shells of Strombus gigas , mollusks that still inhabit the sandy shallows between the island’s north shore and a fringing reef beyond. Imbricated limestone slabs are clustered near some of the coral boulders. In addition, fields of scattered limestone boulders and cobbles near sea level extend mainly southward from limestone sources as much as 1 km inland. Radiocarbon ages have been obtained from 27 coral clasts, 8 lucine valves, and 3 conch shells. All these additional ages predate 1500 cal yr CE, all but 2 are in the range 1000–1500 cal yr CE, and 16 of 22 brain coral ages cluster in the range 1200–1480 cal yr CE. The event marked by these coral and mollusk clasts likely occurred in the last centuries before Columbus (before 1492 CE). The pre-Columbian deposits surpass Anegada’s previously reported evidence for extreme waves in post-Columbian time. The coarsest of the modern storm deposits consist of coral rubble that lines the north shore and sandy fans on the south shore; neither of these storm deposits extends more than 50 m inland. More extensive overwash, perhaps by the 1755 Lisbon tsunami, is marked primarily by a sheet of sand and shells found mainly below sea level beneath the floors of modern salt ponds. This sheet extends more than 1 km southward from the north shore and dates to the interval 1650–1800 cal yr CE. Unlike the pre-Columbian deposits, it lacks coarse clasts from the reef or reef flat; its shell assemblage is instead dominated by cerithid gastropods that were merely stirred up from a marine pond in the island’s interior. In their inland extent and clustered pre-Columbian ages, the coral clasts and associated deposits suggest extreme waves unrivaled in recent millennia at Anegada. Bioclastic sand coats limestone 4 m above sea level in areas 0.7 and 1.3 km from the north shore. A coral boulder of nearly 1 m 3 is 3 km from the north shore by way of an unvegetated path near sea level. As currently understood, the extreme flooding evidenced by these and other clasts represents either an extraordinary storm or a tsunami of nearby origin. The storm would need to have produced tsunami-like bores similar to those of 2013 Typhoon Haiyan in the Philippines. Normal faults and a thrust fault provide nearby tsunami sources along the eastern Puerto Rico Trench.

Soil C quantities of mangrove forests, their competing land uses, and their spatial distribution in the coast of Honda Bay, Philippines

Mangrove forests provide many ecosystem goods and services and they contain large amount of carbon (C) especially in their soil. Yet, their global area is still declining owing to conversion to non-forest land uses. While studies have been conducted on mangrove soil C stocks, our knowledge on how C stocks of mangrove forests compare with those of non-forest land uses that replaced them is still limited. This knowledge is crucial in land use planning and decision-making in the coastal zone. Site-scale mapping and assessments of mangrove soil C stocks and the land uses that replaced them are also limited. The aim of this study was to quantify and compare the soil C stocks in mangrove forests and their competing non-forest land uses (represented by aquaculture pond, coconut plantation, salt pond and cleared mangrove), estimate soil C loss arising from conversion, and model the soil C stock distribution in the entire study site. On the average, the soil C stock of mangrove forests was 851.9±87MgC ha−1 while that of their non-forest competing land uses was less than half at 365.1±31MgC ha−1. Closed canopy mangrove was highest at 1040±104MgC ha−1, followed by open canopy mangrove (640±131MgC ha−1) while aquaculture, salt pond and cleared mangrove had comparable C stocks (454±32, 401±9, 413±25MgC ha−1, respectively) and coconut plantation had the least (42±0.7MgC ha−1). Overall, the reduction in soil C stock (soil C loss) due to land use conversion in mangrove ranged from 398 to 809MgCha−1 (mean: 486.8MgCha−1) or a decline of 57% in soil C stock, on the average. It was possible to model the site-scale spatial distribution of soil C stocks and predict their values with 85% overall certainty using the Ordinary Kriging approach. Results from this study could help inform current discussions on Blue Carbon and REDD+ as well as policy and program development that advance research on soil C conservation and ecosystem services in coastal forested wetlands.

Trace Fossils in Clastic Beachrocks at the Yallahs Salt Ponds, Jamaica: Implications for Beachrock Cementation

ABSTRACT Edwards, T.C.P. and Mitchell, S.F., 2018. Trace fossils in clastic beachrocks at the Yallahs Salt Ponds, Jamaica: Implications for beachrock cementation. The extent and importance of trace fossils preserved in clastic beachrock from the southern section of the Yallahs Salt Ponds on the SE coast of Jamaica are described. The beachrock contains a seaward-dipping facies of cemented sandstones and conglomerates and a landward facies consisting of cemented sandstones packed with the trace fossil Psilonichnus, which is produced by the ghost crab Ocypode quadrata (Fabricius). The seaward-dipping bedded facies represents more than 95% of the beachrock at the Yallahs Salt Ponds and has an exposed height ranging from 6 to 50 cm and lateral continuity of 1 to 200 m. The bioturbated facies, which represents less than 5% of the beachrock at the Yallahs Salt Ponds, was only found at three localities. It has an exposed height of 40 to 60 cm, with outcrops traceable for 6 to 30 m along the beach. These bioturbat...

Evolution of Two Urbanized Estuaries: Environmental Change, Legal Framework, and Implications for Sea-Level Rise Vulnerability

The San Francisco Bay (CA, USA) and the Tagus Estuary (Lisbon, Portugal) share striking similarities in terms of morphology and urban development. A finer analysis of development patterns reveals crucial differences in the extent of shoreline alteration and types of land use that now encroach upon natural estuarine habitat. Through historical map analysis and prior stratigraphic and historical research, we reconstruct in GIS environment the evolution of both estuaries over the last millennia and the relative distribution of different classes of land cover. We also discuss the legal frameworks that accompanied this evolution, and how they have influenced the process of wetland reclamation and landfilling. We compared the legal history and synchronous patterns of development by compiling historical mapping information and resorting to GIS analysis to explore spatial patterns over time. This method was useful in isolating events and decisions that were unique to each of the case studies. The Tagus Estuary has experienced disruption of natural environments for over two millennia. Yet, the State has been able to keep estuarine lowlands under public control, even if vast areas have been transformed into farmland. Public control could allow wetland migration with rising seas and restoration efforts. The San Francisco Bay was affected by several decades of elevated sediment loads in the 19th century, which induced rapid wetland expansion, but virtual cutoff of sediment supply by dams in the 20th century now impairs their ability to accrete. Meanwhile, tidal wetlands were subject to extremely fast and poorly regulated development. Artificially filled and/or drained wetlands were transferred to local governments and private landowners, in violation of the Public Trust Doctrine. The transformation of wetlands into salt ponds, industrial zones and even residential neighborhoods created extensive developed areas at or below sea level, which are vulnerable to even modest rises in sea level. Remaining wetlands are now heavily encroached on their landward side by urban development, which prevents their landward migration. Different legal interpretations of comparable definitions of public trusts and jurisdictions over shorelines may have significant implications for the ability to adapt to sea-level rise.

Administration of tetrodotoxin protects artificially raised juvenile tiger puffer Takifugu rubripes from predators

We examined the effects of tetrodotoxin (TTX) administration on artificially raised tiger puffer Takifugu rubripes juvenile survival after release into a mesocosm with predators to clarify the ecological significance of TTX. Pellets containing three different concentrations of TTX [0 as the control, 7 and 14 mouse units (MU)/g diet] were fed to non-toxic artificially raised T. rubripes juveniles for 10 days. TTX accumulation in the various tissues of fish was detected except for in the control diet group. TTX administration did not affect survival or growth of the fish. One hundred fish from each diet group were released together after TTX administration into a salt pond mesocosm (2650 m2) with predators (Lateolabrax sp.) for 5 days. Survival after release was significantly higher in both the fish fed with the 7 MU TTX/g diet (62%) and the 14 MU TTX/g diet (74%) than in the control fish (32%).

Groundwater Salinity Distribution in Sub-District Kedung, District Jepara

The groundwater salinity in Kedung Sub-district, near the coastal area, is the result of the salt water that comes into the aquifers and the salt water seepage from the surface. The broad groundwater salinity is because of the recent land condition that is resulted from the deposition in the ocean. The nature of the groundwater in-Sub-distric from all aquifers consists of 14% saline groundwater, 48% brackish groundwater and 38% fresh water. The number of community that has brackish until saline ground water property is 19.202 people, so that the domestic water need for the community is 1.344.378 liters/day. Such environmental condition makes the residents make some adaptation. The adaptation of the land use aspect is by making the western region as a fishponds region and the eastern one as a rice fields region. Adaptation in community activities is to fulfill the needs by working as farmers (on the rice fields, fish ponds or salt ponds) or as the fishermen. Adaptation is also made to minimize the threat of disasters, such as the manufacture of levees, weirs or dams and diversions to prevent the spread of tidal flooding.

Produksi Garam Dan Bittern Di Tambak Garam

Rembang Regency could be named as Salt City because they have very high production after Pati Regency. Along the road of Juwana (Pati) - Rembang, salt pond could be seen as square salt sea equipped with windmill to take the sea water from the channel into the pond and is processed into salt. Although salt localproduction is sufficient enough for raw material of industry, therefore best practical technology it is needed. The objective of present work are to improve directly the process of salt production and basic technique for diversiificatio of salt production, i.e. salt and bittern. The result of present works as follows. Getrape type salt pond is applied, where young water embankment is located upstream and the down to seed pond 1, 2, 3, then distributed to cristalization pan. Seawater is taken through primary dykes to pump at elevation of 1.5 m, so still full of water during high tide. On cristalization pan (size of 200 m2) sea water will be settled during 7–10 days until its cristalized. Salt cristal was located under bittern solution could be scrap and collected in collection point. The left-after bittern of 29–30° Be could be flowed back into seed pan uo be collected in bitter collection point. Keywords: Rembang, salt, bittern

Changes in the population genetics of an invasive Spartina after 10 years of management

Spartina foliosa is native to the San Francisco, California, Bay and Estuary. Spartina alterniflora was introduced to the Bay in the 1970s and subsequently hybridized with S. foliosa. Backcrossing created an invasive hybrid swarm able to outcompete S. foliosa within its tidal range and spread into higher and lower intertidal zones, drastically altering ecological communities. The San Francisco Estuary Invasive Spartina Project (ISP) has implemented a treatment program that has reduced the net area of invasive Spartina by 96 % from its peak of 323 hectares. An endangered bird, the California Ridgway’s Rail, takes advantage of habitat characteristics supplied by hybrid Spartina, prompting treatment restrictions in some marshes to preserve hybrid Spartina for the benefit of rails. We investigated changes in the population genetics of the invasion after 10 years of eradication efforts and after three subsequent years without eradication in some locations. Our investigation covered three areas: sites surrounding and including the restricted treatment marshes; sites in the southern Bay similar to proposed salt pond restoration projects; and samples collected Baywide. Our results support previous descriptions of a system of self-fertile hybrid plants that supply seed for mostly localized recruitment into available habitat. Compared to published work from 2003 to 2004, before large-scale eradication efforts began, genetic diversity has generally declined and inbreeding within hybrid populations has increased during and after the period of treatment by the ISP. These observations are perhaps due to pollen limitation as a result of the elimination of most hybrid plants by the ISP. We did not detect strong population genetic boundaries Baywide, but a genetically distinguishable localized introduction was detected in 10 of 11 Bay regions, suggesting leptokurtic dispersal. The restricted treatment areas may allow for continued introgression with S. foliosa, recolonization, and longer persistence of these invasive plants in the San Francisco Bay. Proximity to hybrid Spartina threatens the success of major restoration projects.

IsoCaRB: A novel bioreactor system to characterize the lability and natural carbon isotopic (14C, 13C) signatures of microbially respired organic matter

AbstractOrganic matter is the dominant pool of reduced carbon in marine and freshwater systems. Mineralization of organic matter is largely attributed to complex and diverse microbial communities that mediate degradation and ultimately yield the terminal respiratory product, carbon dioxide (CO2). The factors that constrain the lability and degradation of organic matter remain unclear, but they involve a complex interplay between structural and chemical properties of the compounds, physical properties of the matrices, and the functional potential of the microorganisms that are present. To investigate these relationships, we developed a novel bioreactor system—called Isotopic Carbon Respirometer‐Bioreactor (IsoCaRB)—that permits real‐time monitoring of microbial CO2 production rates and collects sequential samples of this CO2 for off‐line isotopic analyses (13C, 14C). Application of this system to organic‐rich sediments from Salt Pond, MA reveals that organic matter is oxidized both abiotically and microbially, and that the pattern of microbial respiration by the native sediment community is complex, accessing different carbon substrates over the course of incubation. Isotopic measurements show modern organic matter of progressively older ages (≤ ca. 50 yr) is consumed, and this material has variable origins (salt marsh grasses, terrestrial, and marine organic matter). Collectively, the IsoCaRB system provides coupled insights into the sources, ages, and inherent biological and abiotic reactivity of natural organic matter.

Coastal saltpans are a good alternative breeding habitat for Kentish plover Charadrius alexandrinus when umbrella species are present

The loss and degradation of natural habitats in coastal areas worldwide has adversely affected many waterbird species, changing their breeding distribution and reducing their productivity. Anthropogenic habitats such as saltpans can provide alternative or complementary habitats for waterbirds and mitigate the increasing human impact on natural coastal habitats. Unvegetated linear paths between salt ponds are used by ground‐nesting waterbird species to breed but their linear structure may facilitate the detection of nests by predators. This negative effect may, however, be counterbalanced by the advantages of breeding in mixed colonies. To evaluate the importance and the risks of breeding in saltpans we used the Kentish plover Charadrius alexandrinus breeding in coastal saltpans of southern Portugal as a model species. Specifically, we assessed the role of nest‐site characteristics, predation and nesting proximity to species with aggressive antipredator behaviour (black‐winged stilt Himantopus himantopus) on their breeding success. Kentish plovers selected nest‐sites on the edges of paths, with about 20% of water around the nest, and a mean visibility of more than 72%; however nest‐site characteristics were not correlated with nesting success. Predation was the main cause of nest loss in saltpans (42%); carrion crows Corvus corone were responsible for most daylight nest predation (58%) and red fox (Vulpes vulpes; 73%) for night predation. An 8‐yr monitoring plan of a Kentish plover population showed a linear increase in their breeding success as their breeding season increasingly overlapped with that of the black‐winged stilt. An experiment with artificial nests showed a significant increase in the number of exposure days (7 to 12) when these nests were within close distance of black‐winged stilt nests. Overall, our results showed that saltpans are an important alternative breeding habitat for the Kentish plover, especially for the maintenance of mixed species colonies.

Using Discontinuity Mapping to Investigate the Origins of Rock City and Mountain Lake, Giles County, Virginia

Mountain Lake’s unusual location, near the summit of Salt Pond Mountain, VA, in the non-glaciated portion of the Appalachian Mountains, has prompted geologists to study its origin for decades. The northeastern end of the lake abuts an area of heterogeneous colluvial deposits that contain large rectangular blocks of hard Tuscarora Sandstone. This area is known as “Rock City” because of the resemblance of the gaps between the rock blocks to streets and alleys in a city. The purpose of this study was to investigate the origin of Rock City and whether the colluvial deposits within its boundaries are part of a landslide that is possibly responsible for the formation of Mountain Lake. Mapping of Rock City included taking global positioning satellite readings at the corners of rock blocks and along the boundaries of other outcrops, then using ArcMap software to generate maps. Using stereonet analysis, the mode of rock-block displacement was investigated by comparing the measured orientations of principal discontinuity sets forming the rock-block boundaries with discontinuity orientations of undisturbed outcrops. Discontinuity data analysis indicates that Rock City is most likely a landslide that dammed the valley of Pond Drain, forming the lake. The primary mode of slope movement involves lateral spreading associated with extension occurring along discontinuities. The Tuscarora Sandstone blocks comprising Rock City were detached from a scarp face along a northwest-southeast–trending joint set and were displaced laterally toward the west. A seismic event may have triggered slope movement; however, more extensive analysis must be done to rule out other interpretations.

Novel archaeal tetraether lipids with a cyclohexyl ring identified in Fayetteville Green Lake, NY, and other sulfidic lacustrine settings.

The meromictic Fayetteville Green Lake (FGL) is of significant geobiological interest because of microbial cycling of sulfur within and below the permanent chemocline and in the euxinic deep waters. Studies of glycerol dibiphytanyl glycerol tetraethers (GDGTs) may help shed light on understanding the activity of archaeal communities in these habitats. Normal-phase and reversed-phase liquid chromatography/mass spectrometry (LC/MS) analysis on total lipid extracts of environmental samples revealed series of GDGTs with different biphytane structures. Comparison of the mass spectrum of biphytane obtained from separated novel GDGTs with that of a synthetic C40 biphytane confirms our structural assignments. A unique cyclohexyl ring configured in the middle of a C40 biphytane chain was identified in these novel GDGTs. We suggest the trivial name S-GDGTs for these compounds, where 'S' stands for 'sulfidic' and 'six-membered ring'. S-GDGT derivatives composed of biphytanes modified with double bonds and cyclopentane rings were also detected in the samples we analyzed. Intact polar lipid precursors of S-GDGT include compounds with mono- and diglycosyl head groups. The carbon isotopic composition of S-GDGTs and their occurrence in FGL, Messel Shale as well as Salt Pond and salt marshes on Cape Cod suggest that S-GDGTs may be produced by chemoautotrophic archaea that prefer sulfidic conditions. Copyright © 2016 John Wiley & Sons, Ltd.

Regional difference of coastal land use around the Bohai sea based on remote sensing images

With the thriving development of high spatial resolution sensors, an increasing number of metric and sub-metric resolution remote sensing images are currently available, which allows for accurate geometrical analysis of objects at fine scales. Aimed to reveal the regional difference of coast land use in the Bohai Sea, series remote sensing images of HJ-1ACCD obtained in July of 2013 were employed to monitor land use in 5 km coastal zone of 13 regions around the Bohai Sea. Some evaluation index, such as dominant land use type, land use dominant index and land use intensity index were established to evaluate the regional difference of land use in the coast zone. The result shows: there exist obviously regional differences in coast land use around the Bohai Sea. Some regions such as Huludao and Yantai are typical farmland landscape. Some regions such as Dongying and Panjin are typical reed wetland landscape, While Cangzhou is typical fishpond landscape, Weifang and Binzhou are typical salt pond landscape. Land use in coast of Huludao, Yantai and Weifang are single dominated structure, the dominant land use type are farmland in Huludao and Yantai. It is salt pond in Weifang. Their dominant index is all above 0.34. Land use in coast of Tianjin, Qinhudao and other 8 regions are dual structure. The dominant index of dominant land use type ranged from 0.10 to 0.30. The land use intensity index is biggest in coast of Tianjin and Cangzhou with value 2.15 and 2.12, respectively.

Habitat Selection by Forster's Terns (Sterna forsteri) at Multiple Spatial Scales in an Urbanized Estuary: the Importance of Salt Ponds

Abstract. The highly urbanized San Francisco Bay Estuary, California, USA, is currently undergoing large-scale habitat restoration, and several thousand hectares of former salt evaporation ponds are being converted to tidal marsh. To identify potential effects of this habitat restoration on breeding waterbirds, habitat selection of radiotagged Forster's Terns (Sterna forsteri) was examined at multiple spatial scales during the pre-breeding and breeding seasons of 2005 and 2006. At each spatial scale, habitat selection ratios were calculated by season, year, and sex. Forster's Terns selected salt pond habitats at most spatial scales and demonstrated the importance of salt ponds for foraging and roosting. Salinity influenced the types of salt pond habitats that were selected. Specifically, Forster's Terns strongly selected lower salinity salt ponds (0.5–30 g/L) and generally avoided higher salinity salt ponds (≥ 31 g/L). Forster's Terns typically used tidal marsh and managed marsh habitats in proportion to ...

Effects of Salt Pond Restoration on Benthic Flux: Sediment as a Source of Nutrients to the Water Column

Understanding nutrient flux between the benthos and the overlying water (benthic flux) is critical to restoration of water quality and biological resources because it can represent a major source of nutrients to the water column. Extensive water management commenced in the San Francisco Bay, Beginning around 1850, San Francisco Bay wetlands were converted to salt ponds and mined extensively for more than a century. Long-term (decadal) salt pond restoration efforts began in 2003. A patented device for sampling porewater at varying depths, to calculate the gradient, was employed between 2010 and 2012. Within the former ponds, the benthic flux of soluble reactive phosphorus and that of dissolved ammonia were consistently positive (i.e., moving out of the sediment into the water column). The lack of measurable nitrate or nitrite concentration gradients across the sediment-water interface suggested negligible fluxes for dissolved nitrate and nitrite. The dominance of ammonia in the porewater indicated anoxic sediment conditions, even at only 1 cm depth, which is consistent with the observed, elevated sediment oxygen demand. Nearby open-estuary sediments showed much lower benthic flux values for nutrients than the salt ponds under resortation. Allochthonous solute transport provides a nutrient advective flux for comparison to benthic flux. For ammonia, averaged for all sites and dates, benthic flux was about 80,000 kg/year, well above the advective flux range of -50 to 1500 kg/year, with much of the variability depending on the tidal cycle. By contrast, the average benthic flux of soluble reactive phosphorus was about 12,000 kg/year, of significant magnitude, but less than the advective flux range of 21,500 to 30,000 kg/year. These benthic flux estimates, based on solute diffusion across the sediment-water interface, reveal a significant nutrient source to the water column of the pond which stimulates algal blooms (often autotrophic). This benthic source may be augmented further by bioturbation, bioirrigation and episodic sediment resuspension events.

Recovery and the quality of Gypsum from Natural and Artificial Pans of Various Salt-Ponds of Kanyakumari and Tuticorin Districts, Tamilnadu, India.

The story of the salt is the story of mankind. Salt has played a vital role in the development of man's activities, trade, politics, culture and world's economy from pre-historic time. The most abundant source of common salt (NaCl) is sea water, in view of that 71% of earth surface is covered with sea water, which contains 2.5% common salt. Next to sea water the concentration of sodium chloride is high in subsoil brine and backwater brine. The production of common salt is mainly by solar evaporation of sea brine, subsoil and backwater brines. Thus the technique of solar salt production involves fractional crystallization of the salts in different brines. While the process for solar evaporation of brines is same around the world, but the product quality vary considerably. During the production of salt, the valuable by-product of gypsum (CaSO4.2H2O) is also obtained. The sea water contains about 3.6% CaSO4, which is in-exhaustible and can be renewable. The recovery of gypsum from different brines is substantial and its comparable with the production of commercially available mineral gypsum in market. The most influential parameters potentially affecting the crystallization process of gypsum were water, salinity, temperature, type and amount of dissolved organic compounds, PH and organic waste products from microorganisms. The quality of gypsum from natural and artificial pans in the salt ponds of Kanyakumari and Tuticorin districts were taken in to consideration.

Bacterial Diversity in Bohai Bay Solar Saltworks, China.

The microbiota in solar salterns plays an important role in salt production quantitatively and qualitatively. Bohai Bay coast is the major sea salt producing area in China. However, few ecological characterization studies of the Bohai Bay salt ponds, particularly of their microbial diversity, have been conducted. This study investigated the structure and diversity of the bacterial community in Hangu saltworks in response to environmental factors. The brine water was sampled from five selected saltponds within a salinity range of 5.0-19.3% in May, July, and October, 2012. Phylogenetic analysis based on the denaturing gradient gel electrophoresis (DGGE) patterns of the PCR-amplified 16S rRNA gene fragment showed that, rather than pond salinity, especially the month of sampling influenced the structure of the bacterial community in the saltponds, which may be related to the water temperature or other factors fluctuating over the months. Moreover, canonical correspondence analysis of biological and physico-chemical parameters indicated that especially other environmental factors such as nitrogenous and phosphorous nutrient contents and pH structured the microbial community. The relatively high range-weighted richness index and Shannon-Wiener index (H') observed in this study reflect the high level of richness and biodiversity present, though there were substantial fluctuations over the months and salinities of sampling. The fragment of 16S rRNA gene sequence recovered from DGGE bands indicated that the bacterial assemblage in Hangu Saltworks was dominated by members of γ-Proteobacteria (34% of total sequences obtained), followed by Firmicutes (14%) and Bacteroidetes (9%).

Rapid growth and concerted sexual transitions by a bloom of the harmful dinoflagellate Alexandrium fundyense (Dinophyceae).

Transitions between life cycle stages by the harmful dinoflagellate Alexandrium fundyense are critical for the initiation and termination of its blooms. To quantify these transitions in a single population, an Imaging FlowCytobot (IFCB), was deployed in Salt Pond (Eastham, Massachusetts), a small, tidally flushed kettle pond that hosts near annual, localized A. fundyense blooms. Machine‐based image classifiers differentiating A. fundyense life cycle stages were developed and results were compared to manually corrected IFCB samples, manual microscopy‐based estimates of A. fundyense abundance, previously published data describing prevalence of the parasite Amoebophrya, and a continuous culture of A. fundyense infected with Amoebophrya. In Salt Pond, a development phase of sustained vegetative division lasted approximately 3 weeks and was followed by a rapid and near complete conversion to small, gamete cells. The gametic period (∼3 d) coincided with a spike in the frequency of fusing gametes (up to 5% of A. fundyense images) and was followed by a zygotic phase (∼4 d) during which cell sizes returned to their normal range but cell division and diel vertical migration ceased. Cell division during bloom development was strongly phased, enabling estimation of daily rates of division, which were more than twice those predicted from batch cultures grown at similar temperatures in replete medium. Data from the Salt Pond deployment provide the first continuous record of an A. fundyense population through its complete bloom cycle and demonstrate growth and sexual induction rates much higher than are typically observed in culture.

YODISASI GARAM RAKYAT DENGAN SISTEM SCREW INJECTION

Retno Hartati, Edy Supriyo, Muhammad Zainuri, in this paper explain that many salt industry is currently undergoing a inefficiencies process in the production system. Declining quality of salt from the salt ponds and lack of homogeneity in the iodine content of salt briquettes and much KIO3 wasted. So it is necessary to increase the iodine levels in salt. This activity aims to design, create and test a iodized salt machine with a capacity of 1-2 tons per hour and perform quality control on products. Community service activities have been successfully implemented by creating iodized salt machine. The process is done by means of iodized salt machine in the salt product becomes higher and meet ISO standards, in which prior to iodized salt machine the content of KIO3 is 0 ppm and become 50 ppm after using KIO3. Keywords : yodization, salt,screw, injection

Hydration/dehydration cycles imposed on Artemia cysts influence the tolerance limit of nauplii against abiotic and biotic stressors

The brine shrimp Artemia franciscana is an important live feed for fish and shellfish larviculture. Cysts of Artemia are naturally found in a wide variety of harsh environments worldwide where they are exposed to different changing environmental conditions. Artemia cysts are also exposed to different hydration/dehydration (H/D) conditions during the post-harvest processing period in the Artemia processing industry. In this study, cysts of two strains of A. franciscana originating from two different geographical locations—one a natural population from Great Salt Lake (GSL), Utah, USA, and the other cultured in the Vinh Chau (VC) salt ponds, Vietnam—where they experience different environmental factors, were exposed to successive hydration/dehydration (H/D) cycles with the aim of determining the effects of these conditions on the stress (i.e., induction of Hsp70) and functional (i.e., resistance toward abiotic and pathogenic biotic factors) responses of the emerged nauplii. Our results showed that a short period of H/D of the cysts did not appear to have a deleterious effect on the emerged nauplii of both strains, as was evidenced by the absence of significant difference in the survival of nauplii emerged from the control and treated cysts, upon challenge with a thermal stressor or with pathogenic Vibrio campbellii. A limited exposure to H/D treatment even leads to the induction of enhanced thermotolerance in GSL nauplii. In essence, these observations add some insights to our current understanding of stress responses in Artemia under the described experimental conditions. In addition, the impact of H/D cycles associated with stress response should be taken into consideration when Artemia is considered as a model organism for future research and applications.