Ephydra Hians Research Articles

Developmental and reproductive costs of osmoregulation to an aquatic insect that is a key food resource to shorebirds at salt lakes threatened by rising salinity and desiccation

Saline lakes worldwide are undergoing drying, and as lake levels fall and areas contract, salinities increase. There is a critical need for data on salinity impacts to guide conservation for recovery of the aquatic productivity that supports migratory and breeding birds that depend on these habitats. Brine flies are key sources of food to these birds and are adapted for life in saline waters owing to their capacity for osmotic regulation. The sublethal effects on growth, development and reproduction were determined in experiments and field observations with the alkali fly Cirrula hians from alkaline lakes of differing salinity. The cost of osmoregulation to fitness from rising salinity was exhibited in slower growth rates of larvae, smaller size at maturity of pupae, reduced adult emergence success, and lower fecundity. The results identify a salinity management range of 25 to 100 g L−1 that would optimize life history traits and productivity of this insect as a food source for birds.

Evaluation and beneficiation of high sulfur and high alkali fly ashes for use as supplementary cementitious materials in concrete

Coal-fuel power plants with semi-dry or dry flue gas desulfurization (FGD) systems produce high sulfur and/or high alkali fly ashes due to comingling of fly ash with FGD products. Such fly ashes do not meet the SO3 content limit (5.0% max.) of ASTM C618 or are unable to mitigate the alkali-silica reaction. The mineralogy of the sulfur present in these ashes can vary significantly (e.g., CaSO4, CaSO3, Na2SO4) based on the FGD technology used and this affects the performance of these fly ashes in concrete. Thus, the single SO3% limit of ASTM C618 is unable to capture the complexity and performance of fly ash, and this results in elimination of potentially viable pozzolans for concrete. This study performs a systematic investigation of the effect of SO3 type and content in fly ash on various performance parameters of cement-fly ash pastes and mortars, including workability (flow and flow retention), pore fluid pH, setting time, strength development, and potential for deleterious expansion. To better quantify and understand these effects, the study considers both real and doped fly ashes (i.e., a blend of specification-compliant fly ash with target sulfur compounds). The poor performance observed in the case of setting time and pore fluid pH was successfully mitigated using chemical admixtures.

A Note of a Unique Inland, Saline Water Fishery: Brine Flies (Diptera: Ephydridae) of Lake Cuitzeo, Mexico

Fisheries in Cuitzeo, the second largest Mexican lake, used to take place on the permanent freshwater East and Central Basins as opposed to the temporal, saline, and initially thought barren West Basin. The 1980 fisheries collapse forced fishers to look for non-conventional fishing products elsewhere in the lake. The West Basin’s temporal, saline-alkaline, and shallow water provides exceptional habitat for ephydrids to flourish. Locally known as “pupa”, ephydrids are collected in large numbers. Although consumed since pre-Hispanic times, no other commercial fisheries of ephydrids are known worldwide. This study records the species composition and abundance of the “pupa” throughout an annual cycle in the West Basin, where fisheries occur. Two species were found: Ephydra hians and Lamproscatella muria. Ephydrids co-occurred in June and July at the end of the dry season when salinity was highest. L. muria was more abundant (954 ± 2385 ind m−2) than E. hians (94 ± 38 ind m−2). The relatively low salinity of the West Basin favoured L. muria over E. hians, which prefers higher salinities. This “pupa” fishery is still unpredictable due to the astatic nature of the lake, and hence limited economic importance to the local fishers.

Diets of Staging Phalaropes at Great Salt Lake, Utah

ABSTRACTGreat Salt Lake, Utah, USA, is a critical staging area for Wilson's (Phalaropus tricolor) and red‐necked (Phalaropus lobatus) phalaropes. Both phalarope species depend upon abundant invertebrate prey in Great Salt Lake to fuel fall migrations, but the lake currently faces the threat of becoming increasingly saline due to water diversions and climate change. The lake changes may decrease the ability of Great Salt Lake to support the large populations of phalaropes that currently depend upon it. Assessing how a smaller and more saline Great Salt Lake will affect phalaropes is difficult without knowing what phalaropes are consuming during staging. We collected phalaropes from 4 different Great Salt Lake bays from 2012 through 2015 and identified prey items in their upper digestive tracts. We measured wet weights of different food items and examined total mass of food consumed by weighing gizzard contents. Phalarope diets differed across time and bays, and between phalarope species. Red‐necked phalaropes primarily consumed corixids (Corixidae) and brine fly (Ephydra hians, Ephydra cinerea) larva, pupa, and adults, whereas Wilson's phalaropes consumed brine flies, chironomids (Chironomidae) and Daphnia (Daphnia magna). Despite the abundance of brine shrimp (Artemia franciscana) in Great Salt Lake, both phalarope species rarely consumed them. Our results documented that phalaropes of Great Salt Lake are dependent for food in the less‐saline Farmington Bay and on brine flies produced in the hypersaline bays. Such information is critical for wildlife managers who are tasked with ensuring that Great Salt Lake will continue to support the large phalarope populations that depend on the lake's resources. © 2021 The Wildlife Society.

Newly Identified Nematodes from Mono Lake Exhibit Extreme Arsenic Resistance.

Extremophiles have much to reveal about the biology of resilience, yet their study is limited by sampling and culturing difficulties [1-3]. The broad success and small size of nematodes make them advantageous for tackling these problems [4-6]. We investigated the arsenic-rich, alkaline, and hypersaline Mono Lake (CA, US) [7-9] for extremophile nematodes. Though Mono Lake has previously been described to contain only two animal species (brine shrimp and alkali flies) in its water and sediments [10], we report the discovery of eight nematode species from the lake, including microbe grazers, parasites, and predators. Thus, nematodes are the dominant animals of Mono Lake in species richness. Phylogenetic analysis suggests that the nematodes originated from multiple colonization events, which is striking, given the young history of extreme conditions at Mono Lake [7, 11]. One species, Auanema sp., is new, culturable, and survives 500 times the human lethal dose of arsenic. Comparisons to two non-extremophile sister species [12] reveal that arsenic resistance is a common feature of the genus and a preadaptive trait that likely allowed Auanema to inhabit Mono Lake. This preadaptation may be partly explained by a variant in the gene dbt-1 shared with some Caenorhabditiselegans natural populations and known to confer arsenic resistance [13]. Our findings expand Mono Lake's ecosystem from two known animal species to ten, and they provide a new system for studying arsenic resistance. The dominance of nematodes in Mono Lake and other extreme environments and our findings of preadaptation to arsenic raise the intriguing possibility that nematodes are widely pre-adapted to be extremophiles.

Superhydrophobic diving flies (Ephydra hians) and the hypersaline waters of Mono Lake

The remarkable alkali fly, Ephydra hians, deliberately crawls into the alkaline waters of Mono Lake to feed and lay eggs. These diving flies are protected by an air bubble that forms around their superhydrophobic cuticle upon entering the lake. To study the physical mechanisms underlying this process we measured the work required for flies to enter and leave various aqueous solutions. Our measurements show that it is more difficult for the flies to escape from Mono Lake water than from fresh water, due to the high concentration of Na2CO3 which causes water to penetrate and thus wet their setose cuticle. Other less kosmotropic salts do not have this effect, suggesting that the phenomenon is governed by Hofmeister effects as well as specific interactions between ion pairs. These effects likely create a small negative charge at the air-water interface, generating an electric double layer that facilitates wetting. Compared with six other species of flies, alkali flies are better able to resist wetting in a 0.5 M Na2CO3 solution. This trait arises from a combination of factors including a denser layer of setae on their cuticle and the prevalence of smaller cuticular hydrocarbons compared with other species. Although superbly adapted to resisting wetting, alkali flies are vulnerable to getting stuck in natural and artificial oils, including dimethicone, a common ingredient in sunscreen and other cosmetics. Mono Lake's alkali flies are a compelling example of how the evolution of picoscale physical and chemical changes can allow an animal to occupy an entirely new ecological niche.

How alkali flies stay dry

How alkali flies stay dry

ICEBs stabilised with alkali-activated fly ash as a renewed approach for green building: Exploitation of the masonry mechanical performance

The demand for building materials and techniques with reduced environmental impact has been increasing in the last few years. Thus, efforts have been taken to include alternative raw materials with reduced extraction impacts and low embodied energy in their production, namely natural materials and industrial by-products with low or no processing needs. Nevertheless, the lack of technical knowledge about this type of materials leads to issues related with its safety, quality and durability. The work presented in this paper intends to be a contribution on this topic. Thus, an experimental program was carried out to evaluate the mechanical performance of interlocking compressed earth blocks (ICEBs) stabilised with activated alkali fly ash. The main objective of the experimental program was to assess the possibility of further exploiting the mechanical performance of the original dry-stack masonry system, by means of the use of mortared joints. Two alkali-activated binder based earth mortars were used for this purpose, and the results showed that a substantial mechanical improvement is obtained in terms of compression and shear behaviour of the respective masonry.

Recent Desiccation-Related Ecosystem Changes at Lake Abert, Oregon: A Terminal Alkaline Salt Lake

Abstract. Lake Abert, a terminal alkaline salt lake in south central Oregon, has been a key staging area for migratory waterbirds along the Pacific Flyway. In 2014, the lake shrank to about 5% of its maximum size, and its salinity increased from 75 g • L-1 to 250 g • L-1. This resulted in a major ecosystem shift from one dominated at higher trophic levels by invertebrates and waterbirds to one composed primarily of hypersaline-adapted microbes. A large variety of halophilic bacteria and archaea were also detected using 16S rRNA metagenomic sequence analysis. The loss of prey and staging habitat for migratory waterbirds was especially pronounced for Eared Grebe, Red-necked Phalarope, and Wilson's Phalarope, all of which feed on brine shrimp and alkali flies. The last time the lake was in this state was nearly a century ago during the Dust Bowl of the 1930s, which was a once-in-500-years drought. To understand the causes of the current event, we examined hydrological, climatic, and biological data. The prim...

Recent desiccation of Western Great Basin Saline Lakes: Lessons from Lake Abert, Oregon, U.S.A.

Although extremely important to migrating waterfowl and shorebirds, and highly threatened globally, most saline lakes are poorly monitored. Lake Abert in the western Great Basin, USA, is an example of this neglect. Designated a critical habitat under the Western Hemisphere Shorebird Reserve Network, the lake is at near record historic low levels and ultra-high salinities that have resulted in ecosystem collapse. Determination of the direct human effects and broader climate controls on Lake Abert illustrates the broader problem of saline lake desiccation and suggests future solutions for restoration of key habitat values. A 65-year time series of lake area was constructed from Landsat images and transformed to lake volume and salinity. “Natural” (without upstream withdrawals) conditions were calculated from climate and stream flow data, and compared to measured volume and salinity. Under natural conditions the lake would have higher volume and lower salinities because annual water withdrawals account for one-third of mean lake volume. Without withdrawals, the lake would have maintained annual mean salinities mostly within the optimal range of brine shrimp and alkali fly growth. Even during the last two years of major drought, the lake would have maintained salinities well below measured values. Change in climate alone would not produce the recent low lake volumes and high salinities that have destroyed the brine shrimp and alkali fly populations and depleted shorebird use at Lake Abert. Large scale withdrawal of water for direct human use has drastically increased the imbalance between natural runoff and evaporation during periods of drought in saline lakes worldwide but could be offset by establishing an “environmental water budget” to lay a foundation for the conservation of saline lake habitats under continued threats from development and climate change.

Tailoring fly ash activated with bentonite as adsorbent for complex wastewater treatment

Used as adsorbent, alkali fly ash represents a low cost solution for advanced wastewater treatment. The alkali treatment raises sustainability issues therefore, in this research we aim to replace alkali fly ash with washed fly ash (FAw). For improving the adsorption capacity of washed fly ash, bentonite powder (B) was added, as a natural adsorbent with a composition almost identical to the fly ash. The new adsorbent was characterized by AFM, XRD, FTIR, SEM, EDS and the surface energy was evaluated by contact angle measurements. For understanding the complex adsorption process on this mixed substrate, preliminary tests were developed on synthetic wastewaters containing a single pollutant system (heavy metal), binary (two-heavy metals) and ternary (dye and two heavy metals) systems. Experiments were done on synthetic wastewaters containing methylene blue, cadmium and copper, using FAw, B and their powder mixtures. The pseudo-second order kinetics could well model all the processes, indicating a good adsorbent material which can be used for the pollutants removal from wastewater. After adsorption the substrates loaded with pollutants, annealed at 500°C can be reused for padding in stone blocks.

Gadwall Biology in a Hypersaline Environment: Is High Productivity Offset by Postbreeding Mortality?

Abstract The highly herbivorous Gadwall (Anas strepera) is the most salt-tolerant of the North America dabbling ducks and typically breeds in wetlands where salinity does not exceed 15. Small numbers also breed at hypersaline (80-90) Mono Lake, California, which lacks vascular plants. There, Gadwall raise young on the open lake, feed nearly exclusively on alkali flies (Ephydra hians), and minimize osmotic challenges by concentrating activities in areas with access to fresh water. Fledging success is high as a result of abundant food and low predation, but is evidently offset by poor survivorship among postbreeding adults. Failure to complete wing molt and, perhaps, foot disease are implicated. Food in the lake remains abundant well into the autumn. Nevertheless, local birds leave as soon as the young fledge. Many move to nearby freshwater lakes before eventually before continuing to wintering locations in the Central Valley of California. Migrants avoid Mono Lake at this season in favor of nearby freshwat...

The range of protists in Mono Lake, a hypersaline soda lake in the eastern sierras

In spite of the controversies surrounding the environmental deterioration of Mono Lake, and the significant amount of research being done on this remarkably productive body of water, nobody has ever attempted to survey the protists that live beneath its surface. Beginning in July of 2003, we have been trying to remedy this situation and we spent 2 months there studying the protistan species that reside in its waters and since then have been receiving regular sample collections for analysis. Based on the metazoan eukaryotes that live in this lake, which include only Artemia monica, Ephydra hians, rare rotifers and a nematode, we were warned to expect the lake to be depauperate of protists as well. However, we are happy to report that, while not as rich in species as most freshwater lakes, Mono Lake does support a robust population of phagotrophic and heterotrophic protozoa in addition to its many species of unicellular algae, including diatoms. It contains ciliate species representing at least the genera Cyclidium, Frontonia, Lacrymaria, Litonotus, Euplotes and Aspidisca, and the stalked suctorian Tokophrya. Additionally, there are species representing the heliozoa, helioflagellates, choanoflagellates, Pseudobodo, Cercomonas and Chilomastix, among other flagellates. The gymnamoebae are represented by Vanella, Nuclearia, Mayorella and Hartmanella, and, from the Heterolobosea, probable Vahlkampfia and Gruberella species. Micrographs of many of these species will be presented. Work on these species is still very much in its preliminary stages and a more detailed analysis and identification of the protists found in this extreme environment is advancing.This work was partially supported by an NSF grant (MCB 99‐77901) to Robert Jellison.

Carnivorous Canada Geese

Abstract Geese are normally herbivorous. I report an instance of Canada Geese (Branta canadensis) feeding on alkali flies (Ephydra hians) at hypersaline Mono Lake, California. The bout was brief and possibly represented exploratory behavior by inexperienced birds.

Benthos of a prerennially-astatic, saline, soda lake in Mexico

The effects of multiple stressors on the benthic macroinvertebrate community were monitored in Tecuitlapa Norte, a shallow, perennially-astatic, warm, mesosaline, sodaalkaline lake in Mexico. Physico-chemical and biological variables were determined monthly for one year. Tecuitlapa Norte displayed a clear seasonal environmental pattern (dry and rainy seasons). The benthic macroinvertebrate community consisted of five species:Culicoides occidentalis sonorensis Jorgensen,Ephydra hians Say,Stratiomys sp.,Eristalis sp., andLimnophora sp. of which the first two were dominant and the rest scarce.C. occidentalis was the most important species numerically (76 percent of the total), whileE. hians dominated the biomass (73 percent of the total). Primarily salinity and secondarily pH appear to be the most important environmental factors controlling dominance of benthic organisms in Tecuitlapa Norte. Seasonal abundance dynamics of the dominant organisms was associated with phases in their reproductive cycles: environmentally-triggered (i.e., temperature rise, water-level descent) pupation and emergence periods. We concluded that whereas physical and chemical factors (i.e., salinity, pH) exerted the primary control on benthic macroinvertebrate community composition in Tecuitlapa Norte, another assembly of variables (e.g., water-level, temperature) influenced species distribution and abundance.

Saline lake ecosystems of Mexico

This paper aims to draw attention to the need to better know and understand Mexican saline lakes. It does this by outlining their distribution, abundance and location and their physical, chemical and biological characteristics. The influence of climatic factors on saline lakes is discussed. To sharpen the focus of the general discussion, a few Mexican saline lakes are discussed in more detail in each of the indicated topics. Saline lakes are found throughout Mexico, with the greatest number in the northwest and the least in the southeast, and from sea level to altitudes above 2000m. Mexican saline lakes widely fluctuate morphometrically. The majority are tiny, shallow, and temporal with small volumes. Some are large or deep, and perennial with large volumes. Polymixis is common in shallow lakes while deeper ones are monomictic. Temperature and dissolved oxygen fluctuate widely. Alkaline waters are frequent. Mirroring high primary productivity rates, water is often green and turbid but other colors (blue, sepia, purple, yellow) and clear water are also found. Most lakes are sodium chloride or alkali carbonate types. Salts resulting from the combination of sodium with chloride, carbonates and sulfates are common and, to a lesser extent, salts of calcium, potassium, magnesium, lithium and boron are present. Species richness in Mexican saline lakes decreases as salinity rises. Hyposaline lakes display a more diverse biota than hypersaline ones. Organisms commonly found in Mexican saline lakes are: blue-green algae (e.g., Spirulina geitleri, Phormidium tenue), rotifers (Brachionus spp.), anostracans (Artemia spp.), copepods (e.g., Diaptomus, Leptodiaptomus), corixid bugs (e.g., Corisella, Krizousacorixa, Trichocorixella), ephydrids (e.g., Ephydra hians), the neotenic salamander (e.g., Ambystoma spp.), atherinids (e.g., Chirostoma spp.), goodeids (e.g., Goodea spp.), cyprinodontids (e.g., Cyprinodon spp.), poecilids (e.g., Gambusia spp.), and the Caribbean pink flamingo (Phoenicopterus ruber ruber).

Saline lake ecosystems of Mexico

Abstract This paper aims to draw attention to the need to better know and understand Mexican saline lakes. It does this by outlining their distribution, abundance and location and their physical, chemical and biological characteristics. The influence of climatic factors on saline lakes is discussed. To sharpen the focus of the general discussion, a few Mexican saline lakes are discussed in more detail in each of the indicated topics. Saline lakes are found throughout Mexico, with the greatest number in the northwest and the least in the southeast, and from sea level to altitudes above 2000 m. Mexican saline lakes widely fluctuate morphometrically. The majority are tiny, shallow, and temporal with small volumes. Some are large or deep, and perennial with large volumes. Polymixis is common in shallow lakes while deeper ones are monomictic. Temperature and dissolved oxygen fluctuate widely. Alkaline waters are frequent. Mirroring high primary productivity rates, water is often green and turbid but other colors (blue, sepia, purple, yellow) and clear water are also found. Most lakes are sodium chloride or alkali carbonate types. Salts resulting from the combination of sodium with chloride, carbonates and sulfates are common and, to a lesser extent, salts of calcium, potassium, magnesium, lithium and boron are present. Species richness in Mexican saline lakes decreases as salinity rises. Hyposaline lakes display a more diverse biota than hypersaline ones. Organisms commonly found in Mexican saline lakes are: blue-green algae (e.g., Spirulina geitleri, Phormidium tenue), rotifers (Brachionus spp.), anostracans (Artemia spp.), copepods (e.g., Diaptomus, Leptodiaptomus), corixid bugs (e.g., Corisella, Krizousacorixa, Trichocorixella), ephydrids (e.g., Ephydra hians), the neotenic salamander (e.g., Ambystoma spp.), atherinids (e.g., Chirostoma spp.), goodeids (e.g., Goodea spp.), cyprinodontids (e.g., Cyprinodon spp.), poecilids (e.g., Gambusia spp.), and the Caribbean pink flamingo (Phoenicopterus ruber ruber).

97/02325 Decontamination of garbage incineration alkali fly ashes with decreased amount of chelating agents

97/02325 Decontamination of garbage incineration alkali fly ashes with decreased amount of chelating agents

Ultrastructure and seasonal growth patterns of microbial mats in a temperate climate saline-alkaline lake: Goodenough Lake, British Columbia, Canada

Goodenough Lake is a small (ca. 1 by 0.6 km) saline-alkaline lake on the Caribou Plateau in British Columbia, Canada, which has a mean depth of < 1 m, allowing the growth of substantial prokaryote-dominated benthic microbial mats over the entire lake bottom. Microbial mats were investigated on both a detailed ultrastructural level and at a macroscopic level to determine, on a lakewide scale, the seasonally influenced changes that occurred over the course of a spring to fall growth season. The acceleration of phototrophic activity with warming of the lake water in spring could be followed by increases in dissolved oxygen levels, which quickly reached supersaturation early in the summer. The grazing activity of brine fly larvae (Ephydra hians) was found to have a significant influence on mat growth and development patterns. On an ultrastructural level, several types of filamentous cyanobacteria were the main phototrophic organisms present, even in anaerobic parts of the mats, where they were accompanied by purple bacteria. The dominant cyanobacterium present was a large oscillatoriacean form which, in certain parts of the lake, formed unusual columnar structures that had a very low diversity of microbial species in comparison to mats from other regions of the lake. The microbial community also differed in areas of the lake where less saline groundwater springs emerged from the lake bed.Key words: microbial mats, saline-alkaline lakes, cyanobacteria, ultrastructure.

Growth and Survival of Larvae of Ephydra hians Say (Diptera: Ephydridae) on Unialgal Diets

The algae Nitzschia latens Hustedt, Ctenocladus circinnatus Borzi, and two species of Oscillatoria were isolated from Mono Lake, which is near Lee Vining, CA, and used to produce cultures containing only one algal species (unialgal cultures). Survival to pupation and rates of larval growth and development were compared among larvae of Ephydra hians Say, which were reared on one of these algal species or on a diet prepared using the fish food Tetramin. It was found that larvae could be reared from the second larval molt to pupation when fed on a single species of algae. Larvae reared on Nitzschia showed significantly increased weight gain and survival compared with larvae reared on Ctenocladus. Growth performance was always ordered Nitzschia, Oscillatoria, then Ctenocladus. Larvae reared on Nitzschia or Oscillatoria developed significantly faster than those reared on Tetramin. The results indicate that single species of Nitzschia and Oscilatoria are adequate food sources for E. hians growth. Although larvae of this fly appear to be generalist algal herbivores, food quality varies between algal species.