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USGS2012

Novel praziquantel treatment regime for controlling Asian tapeworm infections in pond-reared fish

The Asian tapeworm Bothriocephalus achelognathii is an intestinal fish parasite that is nonnative to but widespread throughout the southwestern United States. Praziquantel is an anthelminthic drug commonly used to treat fish for Asian tapeworm; however, it does not kill tapeworm eggs, so the water in ponds used for fish rearing must be exchanged after treatment. Our objective was to determine whether a system containing both an intermediate copepod host and a definitive fish host for Asian tapeworm could be treated without exchanging the water by using a follow-up treatment for any tapeworms that developed from eggs released before or during the first treatment. Here, we have described a new praziquantel treatment regimen to control Asian tapeworm infections in freshwater-reared fish. To evaluate the efficacy of this regimen, we stocked 50 red shiners Cyprinella lutrensis and an intermediate copepod host, Cyclops vernalis, into each of six pond mesocosms containing artificial macrophytes, sand, and gravel to simulate natural pools and provide suitable substrate for the copepod's life history. The test fish population had been naturally infected with B. achelognathii and had an initial infection prevalence of 14% and an infection intensity of 2.14 ± 2.19 (mean ± SD) worms per fish. Three mesocosms were treated twice, each with 2.5 mg/L praziquantel; 19 d passed between treatments to allow for possible reinfection to occur. After a 2.5-month posttreatment period to allow any remaining tapeworms to reestablish themselves, we killed and dissected all of the remaining fish. No worms were found in treated fish; however, the control group had an infection prevalence of 18 ± 6% and an infection intensity of 3.45 ± 2.1 worms per fish. Based on these results, we concluded that the praziquantel treatment regime administered was efficacious and suggest testing it on a larger scale. We caution that praziquantel has not been approved by the U.S. Food and Drug Administration for use on fish but can be used legally in some situations.

North American Journal of Aquaculture↗

USGS2010

Breeding biology and natural history of the Slate-throated Whitestart in Venezuela

We provide details on the breeding biology of the Slate-throated Whitestart (Myioborus miniatus) from 126 nests found during seven breeding seasons, 2002-2008, at Yacamb?? National Park, Venezuela. Nesting activity peaked in late April and May. Only the female built the nest and incubated the eggs. Males rarely visited the nest during these stages. Mean clutch size (2.1 ?? 0.04 eggs, n = 93) was the smallest recorded for the Slate-throated Whitestart. Incubation and nestling period lengths were 15.3 ?? 0.31 (n = 21) and 10.8 ?? 0.24 (n = 7) days, respectively. Attentiveness (% of time on the nest) during incubation (59 ?? 1.6%, n = 52) was similar to other tropical warblers and much lower than northern relatives. This caused a relatively low egg temperature (34.40 ?? 0.33u C, n = ?? nests, 20 days) compared with north temperate birds. Both parents fed nestlings and increased their provisioning rates with nestling age. Growth rate based on nestling mass (k = 0.521 ?? 0.015) was faster than for other tropical passerines but slower than northern relatives. Predation was the main cause of nesting failure and rate of predation increased with age of the nest. An estimated 15% of nests were successful based on an overall Mayfield daily predation rate of 0.053 ?? 0.007. This study confirms a strong latitudinal variation in life history traits of warblers. ?? 2010 by the Wilson Ornithological Society.

Wilson Journal of Ornithology↗

USGS2021

Scale growth rates and scale circulus deposition rates of marine-stage Atlantic salmon Salmo salar raised under semi-natural conditions

Scale circuli yield valuable information about the life history, age, and growth of a fish. However, because circuli formation is influenced by somatic growth, the rate at which circuli are formed and the factors influencing these rates must be taken into account for the given life stage of the study species. Scales were collected from Atlantic salmon raised in marine net pens off of the coast of Maine in order to characterize the formation of scale circuli and the growth of scales during the ocean phase, and to relate circulus deposition and scale growth rate to water temperature. Fish were sampled 13 times over a period of 25 months. Neither circulus deposition rate nor growth rate were constant through time and the same trend held when circulus deposition and growth were related to thermal experience. Both rates decreased over the course of the study, presumably related to the fish reaching sexual maturity. The results of this study indicate that the pattern of circulus deposition and scale growth of Atlantic salmon vary greatly during the early marine phase, and this dynamic should be taken into account when assessing growth, especially over short time periods.

Newfoundland↗

USGS2014

Laboratory constraints on models of earthquake recurrence

In this study, rock friction ‘stick-slip’ experiments are used to develop constraints on models of earthquake recurrence. Constant-rate loading of bare rock surfaces in high quality experiments produces stick-slip recurrence that is periodic at least to second order. When the loading rate is varied, recurrence is approximately inversely proportional to loading rate. These laboratory events initiate due to a slip rate-dependent process that also determines the size of the stress drop [Dieterich, 1979; Ruina, 1983] and as a consequence, stress drop varies weakly but systematically with loading rate [e.g., Gu and Wong, 1991; Karner and Marone, 2000; McLaskey et al., 2012]. This is especially evident in experiments where the loading rate is changed by orders of magnitude, as is thought to be the loading condition of naturally occurring, small repeating earthquakes driven by afterslip, or low-frequency earthquakes loaded by episodic slip. As follows from the previous studies referred to above, experimentally observed stress drops are well described by a logarithmic dependence on recurrence interval that can be cast as a non-linear slip-predictable model. The fault’s rate dependence of strength is the key physical parameter. Additionally, even at constant loading rate the most reproducible laboratory recurrence is not exactly periodic, unlike existing friction recurrence models. We present example laboratory catalogs that document the variance and show that in large catalogs, even at constant loading rate, stress drop and recurrence co-vary systematically. The origin of this covariance is largely consistent with variability of the dependence of fault strength on slip rate. Laboratory catalogs show aspects of both slip and time predictability and successive stress drops are strongly correlated indicating a ‘memory’ of prior slip history that extends over at least one recurrence cycle.

Journal of Geophysical Research↗

USGS1986

Larval settlement into marine soft-sediment systems: Interactions with the meiofauna

The distribution and abundance of organisms exhibiting complex life cycles, like marine invertebrates, reflect ecological processes operating at all stages in the life history. Few studies have yet considered the mortality patterns of larvae and juveniles. To test whether the permanent meiofauna play a role in macrofaunal larval site-selection, and/or if permanent meiofaunal predators or competitors and disturbers are a significant source of mortality for newly settled macrofaunal juveniles, a series of manipulations of meiofauna were performed. Densities of (1) predatory turbellarians alone, and (2) other meiofauna, were increased in small boxes placed on a holding table in a shallow subtidal habitat. Natural settlement into meiofauna manipulations was examined approximately monthly for a year. Other experiments were conducted to examine the relative importance of site-selection and post-settlement mortality and to determine if settlement was density-dependent or density-independent. Densities of spionid, cirratulid, terebellid, capitellid, and maldanid polychaetes, oligochaetes, bivalves, and amphipods were all reduced by high densities of turbellarians, and sometimes by other meiofauna. Turbellarian predation was responsible for significant post-settlement mortality, but spionids, cirratulids, terebellids, and maldanids also appeared to avoid dense turbellarian treatments. Bivalve densities were reduced by high densities of other meiofauna, probably due to their sedimentary disturbance. Syllid polychaete densities were higher in turbellarian treatments, suggesting that they select for areas with high densities of their prey (small turbellarians). The effects of meiofauna on settlement and survival were greatest in spring and summer. The results of these experiments suggest larval settlement patterns and early juvenile survival should be considered in developing general models of life history and community structure for soft-sediment systems.

Journal of Experimental Marine Biology and Ecology↗

USGS1994

Neural networks for river flow prediction

The surface‐water hydrographs of rivers exhibit large variations due to many natural phenomena. One of the most commonly used approaches for interpolating and extending streamflow records is to fit observed data with an analytic power model. However, such analytic models may not adequately represent the flow process, because they are based on many simplifying assumptions about the natural phenomena that influence the river flow. This paper demonstrates how a neural network can be used as an adaptive model synthesizer as well as a predictor. Issues such as selecting an appropriate neural network architecture and a correct training algorithm as well as presenting data to neural networks are addressed using a constructive algorithm called the cascade‐correlation algorithm. The neural‐network approach is applied to the flow prediction of the Huron River at the Dexter sampling station, near Ann Arbor, Mich. Empirical comparisons are performed between the predictive capability of the neural network models and the most commonly used analytic nonlinear power model in terms of accuracy and convenience of use. Our preliminary results are quite encouraging. An analysis performed on the structure of the networks developed by the cascade‐correlation algorithm shows that the neural networks are capable of adapting their complexity to match changes in the flow history and that the models developed by the neural‐network approach are more complex than the power model.

Journal of Computing in Civil Engineering↗

USGS1995

History and use of remote sensing for conservation and management of federal lands in Alaska, USA

Remote sensing has been used to aid land use planning efforts for federal public lands in Alaska since the 1940s. Four federal land management agencies-the U.S. Fish and Wildlife Service, US. Bureau of Land Management, US. National Park Service, and U.S. Forest Service-have used aerial photography and satellite imagery to document the extent, type, and condition of Alaska's natural resources. Aerial photographs have been used to collect detailed information over small to medium-sized areas. This standard management tool is obtainable using equipment ranging from hand-held 35-mm cameras to precision metric mapping cameras. Satellite data, equally important, provide synoptic views of landscapes, are digitally manipulatable, and are easily merged with other digital databases. To date, over 109.2 million ha (72%) of Alaska's land cover have been mapped via remote sensing. This information has provided a base for conservation, management, and planning on federal public lands in Alaska.

Alaska↗

USGS2015

Natural and unnatural oil slicks in the Gulf of Mexico

When wind speeds are 2 – 10 m s −1 , reflective contrasts in the ocean surface make oil slicks visible to synthetic aperture radar (SAR) under all sky conditions. Neural network analysis of satellite SAR images quantified the magnitude and distribution of surface oil in the Gulf of Mexico from persistent, natural seeps and from the Deepwater Horizon (DWH) discharge. This analysis identified 914 natural oil seep zones across the entire Gulf of Mexico in pre-2010 data. Their &sim;0.1 µm slicks covered an aggregated average of 775 km 2 . Assuming an average volume of 77.5 m 3 over an 8 – 24 h lifespan per oil slick, the floating oil indicates a surface flux of 2.5 – 9.4 × 10 4 m 3 y −1 . Oil from natural slicks was regionally concentrated: 68%, 25%, 7%, and <1% of the total was observed in the NW, SW, NE and SE Gulf, respectively. This reflects differences in basin history and hydrocarbon generation. SAR images from 2010 showed that the 87-day DWH discharge produced a surface-oil footprint fundamentally different from background seepage, with an average ocean area of 11,200 km 2 (SD 5,028) and a volume of 22,600 m 3 (SD 5,411). Peak magnitudes of oil were detected during equivalent, &sim;14-day intervals around 23 May and 18 June, when wind speeds remained <5 m s −1 . Over this interval, aggregated volume of floating oil decreased by 21%; area covered increased by 49% ( p  < .1), potentially altering its ecological impact. The most likely causes were increased applications of dispersant and surface burning operations.

Journal of Geophysical Research C: Oceans↗

USGS2011

Vulnerability of high-latitude soil organic carbon in North America to disturbance

This synthesis addresses the vulnerability of the North American high-latitude soil organic carbon (SOC) pool to climate change. Disturbances caused by climate warming in arctic, subarctic, and boreal environments can result in significant redistribution of C among major reservoirs with potential global impacts. We divide the current northern high-latitude SOC pools into (1) near-surface soils where SOC is affected by seasonal freeze-thaw processes and changes in moisture status, and (2) deeper permafrost and peatland strata down to several tens of meters depth where SOC is usually not affected by short-term changes. We address key factors (permafrost, vegetation, hydrology, paleoenvironmental history) and processes (C input, storage, decomposition, and output) responsible for the formation of the large high-latitude SOC pool in North America and highlight how climate-related disturbances could alter this pool's character and size. Press disturbances of relatively slow but persistent nature such as top-down thawing of permafrost, and changes in hydrology, microbiological communities, pedological processes, and vegetation types, as well as pulse disturbances of relatively rapid and local nature such as wildfires and thermokarst, could substantially impact SOC stocks. Ongoing climate warming in the North American high-latitude region could result in crossing environmental thresholds, thereby accelerating press disturbances and increasingly triggering pulse disturbances and eventually affecting the C source/sink net character of northern high-latitude soils. Finally, we assess postdisturbance feedbacks, models, and predictions for the northern high-latitude SOC pool, and discuss data and research gaps to be addressed by future research.

Journal of Geophysical Research G: Biogeosciences↗

USGS1993

Genetic variability and glacial origins of yellow perch ( Perca flavescens ) in North America

Starch–gel electrophoresis was used to analyze muscle and liver tissue for variation in 13 enzymes representing 31 presumptive loci in yellow perch ( Perca flavescens ) from 13 localities scattered throughout the natural geographic range of the species in North America. Ten loci were polymorphic, but only three, alcohol dehydrogenase ( ADH-1 *), glucose-6-phosphate isomerase ( GPI-1 *), and phosphoglucomutase ( PGM-2 *), exhibited polymorphisms at relatively high frequencies across localities. Western populations were fixed for one allele at ADH-1 *, eastern populations were fixed for another allele, and populations from intermediate locations in Lake Ontario and Pennsylvania had both alleles. The distributions of alleles at GPI-1 * and PGM-2 *were similar to that of ADH-1 *, exhibiting strong differences between eastern and western populations, although the delineation was not as clear. Western populations were much less variable than eastern populations, and the distribution of alleles indicated that the two groups were derived from Mississippi and Atlantic glacial refugia. Populations near the physiographic discontinuity between the Mississippi and Atlantic drainages in western New York and Pennsylvania exhibited an admixture of typically western and eastern alleles. Such observations are consistent with the mixed faunal history of the region and limited postglacial dispersal of western and eastern populations across the boundary.

Canadian Journal of Fisheries and Aquatic Sciences↗

USGS1978

Conceptual models in exploration geochemistry-The Basin and Range Province of the Western United States and Northern Mexico

This summary of geochemical exploration in the Basin and Range Province is another in the series of reviews of geochemical-exploration applications covering a large region; this series began in 1975 with a summary for the Canadian Cordillera and Canadian Shield, and was followed in 1976 by a similar summary for Scandinavia (Norden). Rather than adhering strictly to the type of conceptual models applied in those papers, we have made use of generalized landscape geochemistry models related to the nature of concealment of ore deposits. This study is part of a continuing effort to examine and evaluate geochemical-exploration practices in different areas of the world. Twenty case histories of the application of geochemical exploration in both district and regional settings illustrate recent developments in techniques and approaches. Along with other published reports these case histories, exemplifying generalized models of concealed deposits, provide data used to evaluate geochemical-exploration programs and specific sample media. Because blind deposits are increasingly sought in the Basin and Range Province, the use of new sample media or anomaly-enhancement techniques is a necessity. Analysis of vapors or gases emanating from blind deposits is a promising new technique. Certain fractions of stream sediments show anomalies that are weak or not detected in conventional minus 80-mesh fractions. Multi-element analysis of mineralized bedrock may show zoning patterns that indicate depth or direction of ore. Examples of the application of these and other, more conventional methods are indicated in the case histories. The final section of this paper contains a brief evaluation of the applications of all types of sample media to geochemical exploration in the arid environment of the Basin and Range Province. ?? 1978.

Journal of Geochemical Exploration↗

USGS2012

Estimating westslope cutthroat trout ( Oncorhynchus clarkii lewisi ) movements in a river network using strontium isoscapes

We used natural variation in the strontium concentration (Sr:Ca) and isotope composition ( 87 Sr: 86 Sr) of stream waters and corresponding values recorded in otoliths of westslope cutthroat trout ( Oncorhynchus clarkii lewisi ) to examine movements during their life history in a large river network. We found significant spatial differences in Sr:Ca and 87 Sr: 86 Sr values (strontium isoscapes) within and among numerous spawning and rearing streams that remained relatively constant seasonally. Both Sr:Ca and 87 Sr: 86 Sr values in the otoliths of juveniles collected from nine natal streams were highly correlated with those values in the ambient water. Strontium isoscapes measured along the axis of otolith growth revealed that almost half of the juveniles had moved at least some distance from their natal streams. Finally, otolith Sr profiles from three spawning adults confirmed homing to natal streams and use of nonoverlapping habitats over their migratory lifetimes. Our study demonstrates that otolith geochemistry records movements of cutthroat trout through Sr isoscapes and therefore provides a method that complements and extends the utility of conventional tagging techniques in understanding life history strategies and conservation needs of freshwater fishes in river networks.

Canadian Journal of Fisheries and Aquatic Sciences↗

USGS2022

Seasonal impoundment management reduces nitrogen cycling but not resilience to surface fire in a tidal wetland

Hydrology and salinity regimes of many impounded wetlands are manipulated to provide seasonal habitats for migratory waterfowl , with little-known consequences for ecosystem structure and function. Managed hydrology can alter ecosystems by directly changing soil properties and processes and by influencing plant community dynamics. Additionally, management history may influence ecosystem response to disturbance, including fires. To better understand how wetland management regime influences ecosystem response to disturbance, we quantified elevation, soil nitrogen concentrations and process rates, and plant community structure and diversity in a natural experiment following the 2018 Branscombe Fire. We measured paired burned-unburned patches in both tidally-influenced and managed, seasonally-impounded wetlands in Suisun Marsh, California, USA. Unburned ecosystem structure and nutrient cycling differed by wetland management history; unburned impounded wetlands were ∼1 m lower in elevation and plant community composition was dominated by succulents whereas the unburned tidal wetland was dominated by graminoids. Unburned impounded wetland soil nitrogen cycling (potential nitrification and denitrification) rates were <28% of those measured in unburned tidal wetland soils and soil extractable nitrate, ammonium, and dissolved inorganic phosphorus concentrations were also substantially lower in unburned impounded than unburned tidal wetlands. Despite these differences in pre-disturbance (i.e., unburned) conditions, all soil processes recovered to baseline levels within 6 months after surface fire, and we found no evidence of plant community change 1 year after fire in either wetland management type. Overall, water management history exerted stronger control on ecosystem processes and structure than surface fire disturbance. Low extractable soil nitrate and potential denitrification rates may indicate limitation of soil nitrogen removal in impounded wetlands, with implications for downstream environmental quality and eutrophication across managed landscapes.

California↗

USGS2019

Evaluation of potential sources of sauger Sander canadensis for reintroduction into Lake Erie

Sauger ( Sander canadensis ) supported recreational and commercial fisheries in Lake Erie until the fishery collapsed in the early-1950s, with extirpation of sauger occurring soon after. Previous attempts to rebuild populations via stocking programs were unsuccessful, and the reasons for lack of success are unclear. The Ohio Department of Natural Resources-Division of Wildlife is re-examining the feasibility of reintroducing sauger because the current fish community and habitat conditions appear more suitable for sauger survival and proliferation. Selecting potential sources for reintroduction programs requires consideration of several factors. Donor and recipient ecosystems and life histories should be similar, the source population should have sufficient genetic diversity to withstand losses in diversity associated with hatchery practices, and the source and donor populations should have similar genetic diversity metrics and should be accessible while broodstock is developed. A review of the literature and a genetic analysis of historical sauger collections from Lake Erie and contemporary samples from possible donor populations in five different watersheds was performed to evaluate potential candidate sources for a re-introduction program. We compared genetic diversity, life history parameters, and ecosystem conditions of historical Lake Erie sauger to contemporary sauger populations from the Ohio River (Bellville, Meldahl, and New Cumberland pools), Missouri River, Ottawa River, Lake of the Woods, and Lake Winnebago. While life history and ecological conditions were similar across populations, there was genetic differentiation among potential donor sources and historical collections of sauger from Lake Erie, with contemporary populations from the Ohio River being most like historic Lake Erie sauger.

Lake Erie↗

USGS1985

Forecasts and predictions of eruptive activity at Mount St. Helens, USA: 1975-1984

Public statements about volcanic activity at Mount St. Helens include factual statements, forecasts, and predictions. A factual statement describes current conditions but does not anticipate future events. A forecast is a comparatively imprecise statement of the time, place, and nature of expected activity. A prediction is a comparatively precise statement of the time, place, and ideally, the nature and size of impending activity. A prediction usually covers a shorter time period than a forecast and is generally based dominantly on interpretations and measurements of ongoing processes and secondarily on a projection of past history. The three types of statements grade from one to another, and distinctions are sometimes arbitrary. Forecasts and predictions at Mount St. Helens became increasingly precise from 1975 to 1982. Stratigraphic studies led to a long-range forecast in 1975 of renewed eruptive activity at Mount St. Helens, possibly before the end of the century. On the basis of seismic, geodetic and geologic data, general forecasts for a landslide and eruption were issued in April 1980, before the catastrophic blast and landslide on 18 May 1980. All extrusions except two from June 1980 to the end of 1984 were predicted on the basis of integrated geophysical, geochemical, and geologic monitoring. The two extrusions that were not predicted were preceded by explosions that removed a substantial part of the dome, reducing confining pressure and essentially short-circuiting the normal precursors.

Journal of Geodynamics↗

USGS2020

Pallid sturgeon seasonal habitat selection in a large free-flowing river, the lower Mississippi River

Pallid sturgeon Scaphirhynchus albus (Forbes & Richardson, 1905, Bulletin of the Illinois State Laboratory of Natural History, 1905, 7, 37) are an endangered riverine sturgeon native to the Mississippi and Missouri rivers, and declining numbers have been attributed to multiple stressors, including habitat loss and alteration. The lower Mississippi River provides a useful context to assess pallid sturgeon habitat selection because, although altered for flood control and navigation, it provides a free-flowing system with a diversity of habitats and a minimally altered hydrograph. A discrete choice model of data collected year-round from two reaches for 3–5 years revealed changes in habitat selection across water temperatures and river stages representative of seasonal variation in habitat for 116 telemetry-tagged pallid sturgeon. Natural bank, island tip, and secondary channel were positively selected and main channel, although frequently used, was avoided. The degree of selection varied among river stages, water temperatures, and reaches. Habitat selection appears to be strongly influenced by preference for locations with moderate depth (median 11.7 m; lower and upper quartiles 8.1 m and 16.3 m) and moderate current velocity (median 0.9 m/s; lower and upper quartiles 0.7 m/s and 1.2 m/s).

Alabama, Arkansas, Louisiana, Mississippi↗

USGS2009

Integrating disparate lidar datasets for a regional storm tide inundation analysis of Hurricane Katrina

Hurricane Katrina was one of the largest natural disasters in U.S. history. Due to the sheer size of the affected areas, an unprecedented regional analysis at very high resolution and accuracy was needed to properly quantify and understand the effects of the hurricane and the storm tide. Many disparate sources of lidar data were acquired and processed for varying environmental reasons by pre- and post-Katrina projects. The datasets were in several formats and projections and were processed to varying phases of completion, and as a result the task of producing a seamless digital elevation dataset required a high level of coordination, research, and revision. To create a seamless digital elevation dataset, many technical issues had to be resolved before producing the desired 1/9-arc-second (3meter) grid needed as the map base for projecting the Katrina peak storm tide throughout the affected coastal region. This report presents the methodology that was developed to construct seamless digital elevation datasets from multipurpose, multi-use, and disparate lidar datasets, and describes an easily accessible Web application for viewing the maximum storm tide caused by Hurricane Katrina in southeastern Louisiana, Mississippi, and Alabama.

Journal of Coastal Research↗

USGS2013

The stability of sulfate and hydrated sulfate minerals near ambient conditions and their significance in environmental and planetary sciences

Sulfate and hydrated sulfate minerals are abundant and ubiquitous on the surface of the Earth and also on other planets and their satellites. The humidity-buffer technique has been applied to study the stability of some of these minerals at 0.1 MPa in terms of temperature-relative humidity space on the basis of hydration-dehydration reversal experiments. Updated phase relations in the binary system MgSO 4 -H 2 O are presented, as an example, to show how reliable thermodynamic data for these minerals could be obtained based on these experimental results and thermodynamic principles. This approach has been applied to sulfate and hydrated sulfate minerals of other metals, including Fe (both ferrous and ferric), Zn, Ni, Co, Cd, and Cu. Metal-sulfate salts play important roles in the cycling of metals and sulfate in terrestrial systems, and the number of phases extends well beyond the simple sulfate salts that have thus far been investigated experimentally. The oxidation of sulfide minerals, particularly pyrite, is a common process that initiates the formation of efflorescent metal-sulfate minerals. Also, the overall abundance of iron-bearing sulfate salts in nature reflects the fact that the weathering of pyrite or pyrrhotite is the ultimate source for many of these phases. Many aspects of their environmental significance are reviewed, particularly in acute effects to aquatic ecosystems related to the dissolution of sulfate salts during rain storms or snow-melt events. Hydrous Mg, Ca, and Fe sulfates were identified on Mars, with wide distribution and very large quantities at many locations, on the basis of spectroscopic observations from orbital remote sensing and surface explorations by rovers. However, many of these findings do not reveal the detailed information on the degree of hydration that is essential for rigorous interpretation of the hydrologic history of Mars. Laboratory experiments on stability fields, reactions pathways, and reaction rates of hydrous sulfates likely to be found on Mars enhance our understanding of the degrees of hydration of various sulfates that should currently exist on Mars at various seasons and locations and during various atmospheric pressure and obliquity periods. Two sets of systematic experiments were described; one on hydrous Mg sulfates and the other on hydrous Fe 3+ sulfates. Also, their implications to Mars sulfates mineralogy were discussed.

Journal of Asian Earth Sciences↗