South Arm Research Articles

Ultrahigh-Pressure Metamorphic Rocks in the Bantimala Mélange Complex and Its Implication to Cretaceous Tectonics in the South Arm of Sulawesi

Bantimala Mélange Complex is about 75 Km to the North of Makassar, the capital city of South Sulawesi Province. The presence of High-pressure Metamorphic Rocks, and Ultrahigh Pressure in the Bantimala Mélange Complex, has been known and studied by a number of geologists. Eclogite and Blue Schist are Ultrahigh, and High-pressure metamorphic rocks in the Bantimala Mélange Complex which have important significance in explaining the Cretaceous tectonics in this area. Furthermore, Bantimala Eclogite is the only Ultrahigh-pressure metamorphic rock known to be exposed in Sulawesi. The results of thin section analysis of Eclogite show the presence of Omphacite Minerals, and Coesite as an index mineral for Ultrahigh pressure metamorphic rocks. While in Blue Schist with Glaucophane Minerals are found which are partially replaced by Chlorite which indicates the presence of Poly-metamorphism as a result of retrogradation from Ultrahigh pressure to High pressure and to Medium pressure metamorphic rocks. Radiometric age dating using the Ar40/Ar39 method shows an age spectrum of 100 Ma-114 Ma (Early Cretaceous). The 114 Ma, age is interpreted as the age of Eclogite’s Ultrahigh pressure metamorphic rocks formation with respect to the peak of subduction tectonics. Whereas the age of 100 Ma before now is interpreted as the age of exhumation or collision as the end of the Cretaceous tectonic subduction in the South Arm of Sulawesi or in the East or Southeast of Sundaland.

PyBIRALES: A Radar Data Processing Backend for the Real-Time Detection of Space Debris

The growing population of artificial satellites in near-Earth orbit has made the monitoring of orbital debris objects ever more important. Orbital debris objects pose a threat to these satellites as their orbit cannot be changed in order to avoid a collision. In recent years, the European Space Agency (ESA)’s Space Surveillance and Tracking (SST) programme has been assisting national institutions in the upgrading of their space debris detection and monitoring capabilities. One of the latest such systems within this programme is the BIRALES space surveillance system based in Italy. The receiving antenna is a radio telescope that is made up of 32 receivers which are placed on eight parabolic cylindrical reflectors of the North–South arm of the Istituto Nazionale di Astrofisica (INAF)’s Northern Cross. This work introduces a new software backend which was developed for this novel space debris sensor. The system was designed to be a fast, highly configurable software backend for the radio telescope’s acquisition and processing system and whose monitoring and control can be realized by a simple front-end web-based application. The real-time detection of Resident Space Object (RSO) is an important prerequisite for such a system as it gives the operator an immediate feedback loop on any detections whilst keeping the storage requirements at a minimum given that there is no need to save the raw data. The detection of high-velocity objects is achieved by means of a specially developed data processing pipeline that uses the received raw antenna voltages to generate a number of beams, collectively known as a multipixel, that cover the Field of View (FoV) of the instrument. The trajectory of the detected objects is determined by considering the illumination sequence within this multipixel. The initial results on known objects represent the first steps in extending the growing network of European SST systems.

An Ecological Perspective on Dolomite Formation in Great Salt Lake, Utah

Protodolomite was detected in sediments from Great Salt Lake (GSL), Utah, U.S.A. that have no history of elevated temperature or pressure, conditions that are thought to promote dolomitization of sedimentary carbonates. Protodolomite was abundant in a non-oolitic sediment core from the South Arm (SA) of GSL at 26% salinity. Protodolomite was also abundant in a non-oolitic NA sediment hand sample yet was absent in a nearby oolitic sediment hand sample in locations that likely receive allochthonous nutrients. Protodolomite was not detected in benthic photosynthetic mats from the SA. However, the mats comprised aragonite with halite and minimal calcite; benthic photosynthetic mats do not form in the NA. To begin to identify potential controls on the formation of protodolomite in the SA and NA of GSL, the composition and abundance of 16S rRNA gene transcripts, carbon cycling activities, and porewater geochemistry of the sediment cores were characterized. Transcripts affiliated with a dominant halophilic, heterotrophic sulfate-reducing bacterium were detected in the uppermost sections of the SA core and their abundance was positively correlated with rates of acetate oxidation/assimilation and concentrations of sulfide. Differences in the quality of organic matter between the SA and NA cores, as indicated by carbon to nitrogen ratios, indicate fresh deposition of photosynthetic biomass at the SA sediment core site but not in the NA sediment core site. Sediment grains from the SA core exhibit micrometer-sized euhedral protodolomite crystals that were not detected in the NA core. Collectively, these observations suggest that deposition of photosynthetic biomass drives the development of a sharp, anoxic lens of heterotrophic sulfate reduction. Sulfide, in turn, may promote dehydration of Mg2+-water complexes and primary protodolomite nucleation and growth. The scarcity of dolomite in the NA sediment core may result from constraints imposed by a combination of extreme hypersalinity and depositional environment on phototrophs and sulfate reducers, their activities, and the thermodynamics of protodolomite formation.

In search of floating algae and other organisms in global oceans and lakes

Surface floating macroalgae, microalgae, and other marine and freshwater organisms have been reported in many specific regions around the globe. However, it is technically challenging to identify similar occurrences, or other types of floating organisms or materials, within the vast global oceans and lakes. In this study, we address this challenge through combining global-scale, 375-m resolution false-colored Red-Green-Blue (FRGB) imagery from the Visible Infrared Imaging Radiometer Suite (VIIRS) in NOAA's online Ocean Color Viewer (OCView) for visual inspection and data from several other satellite sensors for spectral diagnostics. In the FRGB imagery, the near-infrared (NIR) band (862 nm) is used as the green channel, which is sensitive to floating algae and organisms/materials on the water surface. Visual inspection of the daily FRGB VIIRS imagery from January 2018 to October 2019 reveals the appearance of various slicks with different colors in many ocean regions and lakes. Combined with spectral diagnostics of the quasi-concurrent Sentinel-3A/3B Ocean and Land Colour Instrument (OLCI) and other higher spatial resolution satellite data as well as knowledge of local oceanography/limnology, most of these elongated or diffuse image features can be identified as Ulva, Sargassum, Noctiluca, Trichodesmium, Microcystis, oil slicks, or pumice rafts. Some of these identified features are found in regions where such occurrences have never been reported before. Some features are of unknown type as they have not been reported previously from remote sensing. In such cases, contemporaneous scientific literature and news reports as well as spectral diagnostics allow for educated inferences to be made. One example is from surface features in the northern Gulf of Maine, Bay of Fundy, and Southwest of Nova Scotia between early June and early July of 2019. Spectral shapes of the FRGB image features indicate transparent materials lacking pigments. Knowledge of local fisheries oceanography and frequent news reports all suggest that these unknown image features may be aggregations or blooms of sea jellies and, to a lesser extent, salps. Another example is from the Great Salt Lake, where image features in the south arm of the lake are speculated to be caused by aggregations of brine shrimp eggs. Once confirmed from field sightings, these findings may represent a milestone in satellite remote sensing because previously remote sensing could only be used to infer oceanographic environments conducive to sea jellies or shrimps. In addition to the findings presented here, the approach in this study may serve as a template to discover various known and unknown types of floating algae and organisms/materials as well as to routinely monitor and track their distributions and movements.

Effect of Culture Depth and Season on the Condition and Reproductive Indices of Blue Mussels (Mytilus edulis L.) Cultured in a Cold-Water Coastal Environment

Condition, growth, and reproductive indices of blue mussels (Mytilus edulis) grown in deep and shallow sites were studied from May to December 2016 in the South Arm region of Notre Dame Bay, Newfoundland. The region was shown to be characterized by a seasonal thermocline that formed in April and lasted to October annually, resulting in a cold-water deep layer (mean annual temperature: 4.36 ± 5.1°C) and a comparatively warmer surface layer (mean annual temperature: 5.81 ± 6.3°C). The deepwater culture sites extended into the cold-water layer and the shallow sites were typically in the warmer layer above. Mussels grown in shallow sites had longer and heavier shells than those from deepwater sites, likely linked to warmer surface waters. Both reproductive and physiological condition indices were high for mussels from both culture depths in May. Physiological condition declined for both deep and shallow cultured mussels from May through to August. Mussels from deep sites, however, had a higher overall mean dry tissue weight: wet tissue weight ratio for the study period. Reproductive indices, including measurements of reproductive output, declined for shallow mussels from May through to August, but remained high for deep mussels until August when a significant spawn occurred for mussels from both depths. In addition, mussels from deep sites were observed to maintain themselves in a prespawning ripe stage for a longer period than those from shallow sites. Variations in physiological and reproductive indices for mussels from each respective culture depth were thought to be linked to differences in the environmental characteristics of the deep and shallow water layers, including rate of temperature change and potential differences in phytoplankton quality and energetics. The additional data provided in the present study add to the current understanding of the effects of the deepwater environment on mussel reproduction patterns and its relationship to production meat yield. The data will help in highlighting the benefits of using deepwater sites leading to increased environmental sustainability for mussel culture in subarctic coastal environments such as those on the north coast of Newfoundland.

Effects of Salinity on Microbialite‐Associated Production in Great Salt Lake, Utah

Organosedimentary structures (microbialites) cover ~20% of the south arm of the hypersaline Great Salt Lake (GSL). Photosynthetic microbial mats associated with microbialites support secondary production in GSL, including that of brine shrimp (Artemia). However, the effects of predicted increases in lake salinity on the primary and secondary production of microbialites and Artemia, respectively, are not known. Here, we show that salinities >20% significantly influenced microbialite microbial community composition, abundance, and productivity and Artemia survivability. Results indicate that increased salinity affects primary and secondary production, which could have negative effects on higher ecological compartments dependent on these species, including migratory birds. Photo credit: Melody Lindsay. Photo credit: Melody Lindsay. Photo credit: Melody Lindsay. Photo credit: Melody Lindsay. These photographs illustrate the article “Effects of salinity on microbialite-associated production in Great Salt Lake, Utah” by Melody R. Lindsay, Rachel E. Johnston, Bonnie K. Baxter, and Eric S. Boyd published in Ecology. https://doi.org/10.1002/ecy.2611

Effects of salinity on microbialite-associated production in Great Salt Lake, Utah.

Microbialites, organosedimentary carbonate structures, cover approximately 20% of the basin floor in the south arm of Great Salt Lake, which ranges from ~12 to 15% salinity. Photosynthetic microbial mats associated with these benthic mounds contribute biomass that supports secondary production in the ecosystem, including that of the brine shrimp, Artemia franciscana. However, the effects of predicted increases in the salinity of the lake on the productivity and composition of these mats and on A. franciscana fecundity is not well documented. In the present study, we applied molecular and microcosm-based approaches to investigate the effects of changing salinity on (1) the primary productivity, abundance, and composition of microbialite-associated mats of GSL, and (2) the fecundity and survivability of the secondary consumer, A. franciscana. When compared to microcosms incubated closest to the insitu measured salinity of 15.6%, the abundance of 16S rRNA gene templates increased in microcosms with lower salinities and decreased in those with higher salinities following a 7-week incubation period. The abundance of 16S rRNA gene sequences affiliated with dominant primary producers, including the cyanobacterium Euhalothece and the diatom Navicula, increased in microcosms incubated at decreased salinity, but decreased in microcosms incubated at increased salinity. Increased salinity also decreased the rate of primary production in microcosm assays containing mats incubated for 7weeks and decreased the number of A. franciscana cysts that hatched and survived. These results indicate that an increase in the salinity of GSL is likely to have a negative impact on the productivity of microbialite communities and the fecundity and survivability of A. franciscana. These observations suggest that a sustained increase in the salinity of GSL and the effects this has on primary and secondary production could have an upward and negative cascading effect on higher-trophic-level ecological compartments that depend on A. franciscana as a food source, including a number of species of migratory birds.

Walanae Fault Kinematic Deduced from Geometric Geodetic GNSS GPS Monitoring

The western Sulawesi region has the main structural boundary, the Palu Koro Fault which divides from Palu Bay at the northest part to Central Sulawesi and continues into the Bone Gulf in southest part. In the southern part of this region, namely the South Sulawesi Arm zone, there is a Walanae fault which is defined as a sinistral wrench with a NW-SE direction that divides the South Arm of Sulawesi. This fault in the northern part is expected to continue to the northwest intersecting the Makassar Strait and unite with Paternoster-Lupar (Kalimantan) sutures and at the southest ending in Flores thrust fault. Walanae fault system did not only have one strand but was divided into 4 parts, namely the northern East Walanae Fault with a slip rate of 6.634 mm/year and the southern part with a 7.097 mm/year of slip rate, as well as the northern part of West Walanae Fault with a slip rate of 4.528 mm/year and the southern part with a slip rate of 3.270 mm/year. The northern part of Walanae fault system has opening or spreading pattern occurs that is in harmony with the formation of Walanae depression. By using simple geometric modeling, we found the fault system have 2 strain partitions with dominant sinistral strike slip pattern at southern part and combination between left lateral strike slip with thrust fault pattern at northern part.

Hydrodynamics of a channel occupied by the aquaculture industry in southern Chile: implications for connectivity between farms

AEI Aquaculture Environment Interactions Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AEI 10:291-307 (2018) - DOI: https://doi.org/10.3354/aei00268 Hydrodynamics of a channel occupied by the aquaculture industry in southern Chile: implications for connectivity between farms Marcus Sobarzo1,2,*, Luis Bravo3,4, Claudio Iturra5, Alfredo Troncoso1, Roberto Riquelme6, Patricio Campos7, Cristian Agurto8 1Departamento de Oceanografía, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, 4030000 Concepción, Chile 2Centro Interdisciplinario para la Investigación Acuícola (INCAR), 4030000 Concepción, Chile 3Departamento de Biología Marina, Facultad de Ciencias del Mar, Universidad Católica del Norte, 1780000 Coquimbo, Chile 4Núcleo Milenio en Ecología y Manejo Sustentable de Islas Oceánicas (ESMOI), Universidad Católica del Norte, 1780000 Coquimbo, Chile 5Programa de Postgrado en Oceanografía, Departamento de Oceanografía, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, 4030000 Concepción, Chile 6Departamento de Ingeniería Matemática, Facultad de Ciencias Físicas y Matemáticas, Universidad de Concepción, 4030000 Concepción, Chile 7Instituto de Ciencias y Tecnología, Universidad Arturo Prat, 5480000 Puerto Montt, Chile 8Centro de Biotecnología, Universidad de Concepción, 4030000 Concepción, Chile *Corresponding author: msobarz@udec.cl ABSTRACT: Residual circulation from nonlinear interaction of the tidal currents with topography in channels, fjords and bays can be important to represent the distance traveled by suspended materials in the water column (e.g. pathogens). Here the role of the semidiurnal tidal excursion was compared with residual currents, during autumn 2011, to evaluate the connectivity among aquaculture production centers in Caucahue Channel (Chiloe Island, southern Chile), which has been widely occupied by the aquaculture industry. During 2015, around 30000 t of 3 different species of salmon were harvested in this channel, representing 3.7% of the national production. Along- and cross-channel tidal currents explained around 80 and 40-60% of the total variance, respectively. Thus, the major residual circulation came from the cross-channel component (40-60% of the total variance) caused by tidal asymmetry. We hypothesized that this asymmetry is related to the nonlinear interaction of the oscillatory flow with the Quemchi constriction. The residual advective distances (Ladv) were compared with tidal excursion (Lexc) and biological diffusivity (Ldiff) scales, considering the distances between centers (Lint), the size of the centers (Lcen) and the length of the south arm of the Cauchaue Channel (L = 11 km). For 3 d time scales, the Ladv/Lexc ratio fluctuated between 1.3 and 8, approximately, implying that, although the advective scale is greater, the tidal flow is still intense enough to favor the retention of pathogens. For larger time scales that consider longer-lived pathogens (e.g. greater than 15 d), this ratio grows 1 order of magnitude. In this scenario and in the event of an outbreak within the channel, pathogens could be exported. KEY WORDS: Tidal excursion · Long-term residual advection · Tidal asymmetry · Chilean aquaculture industry · Waterborne pathogens Full text in pdf format PreviousNextCite this article as: Sobarzo M, Bravo L, Iturra C, Troncoso A, Riquelme R, Campos P, Agurto C (2018) Hydrodynamics of a channel occupied by the aquaculture industry in southern Chile: implications for connectivity between farms. Aquacult Environ Interact 10:291-307. https://doi.org/10.3354/aei00268 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AEI Vol. 10. Online publication date: July 04, 2018 Print ISSN: 1869-215X; Online ISSN: 1869-7534 Copyright © 2018 Inter-Research.

Study on Gold and base metal occurrence in Uluwai Prospect, Western Latimojong Mountain, South Sulawesi

Uluwai Prospect is located in the northern part of South Arm of Sulawesi along the eastern part of the Kalosi Fold Belt and Latimojong Mountain. The area is generally characterized by moderate to rugged topography area with elevation in the range of 700 to 1400 m above sea level in the mountainous complex called Latimojong Mountain Complex. The mineralization is characterized by a relatively simple sulphide ore mineral assemblage consists of pyrite, sphalerite and chalcopyrite. Samples were collected in areas showing abundant sulphide minerals where younger faults cut the bedding and foliation of country rocks. A number of silicified zones have been observed, as well as float material containing disseminated pyrite, chalcopyrite, and sphalerite with hematite, goethite and limonite. Some alteration types have been observed including sericitization, albitization, carbonatization and silisification. The samples collected indicated that the mineralisation is contained within metasedimentary (sandstone to mudstone) and greenschist. Geochemical analyses from 16 samples including 5 stream sediment samples indicated that the most promising mineralization occur in the prospect area are copper (Cu) and zinc (Zn). This is also supported by the abundance of chalcopyrite and sphalerite in some highly altered samples. Assaying of the collected samples revealed most of samples contain relatively low gold (Au) concentration. However, two samples contain 0.007 and 0.01 ppm of Au. In the mineralized area, Zn concentrations are up to 134 ppm, Cu up to 120 ppm and Pb up to 18 ppm and As up to 70 ppm. There is no clear relationship that exists between Au and the base metals except that one of the samples with highest Au values tend to have high Zn and As. This unclear pattern also shown by Cu, Pb and Zn. Base metal concentration in stream sediment samples show a relatively stable pattern than in rock samples. Arsenic tends to be elevated in base metal rich samples. Sb and Mo are relatively low in all sample type. However, Mo values will be high in the samples which contain highest Cu and Zn.

LA-ICP-MS zircon U–Pb and muscovite K–Ar ages of basement rocks from the south arm of Sulawesi, Indonesia

The zircon U–Pb and muscovite K–Ar age from the Bantimala, Barru and Biru basement complexes in the South Arm of Sulawesi, Indonesia provide new information regarding the timing of magmatism, metamorphism and sedimentation in this region and have implications for the origin and evolution of the study area. The study area is at the juncture between the southeast margin of Sundaland and Bird's Head-Australia. The age of both the zircon U–Pb of detrital materials in the Bantimala Complex and the muscovite K–Ar of amphibolite in the Biru Complex fall in the Late Early Cretaceous (between 109 and 115Ma), which is a similar age range to previous data for both the sedimentary and metamorphic rocks. The youngest detrital zircon in the schist samples from the Barru Complex fall into the Triassic in age (between 243 and 247Ma). These age data indicate that the protolith of all three basement complexes were involved in the subduction system and metamorphosed in the late Early Cretaceous, but there are several differences in their deposition environment under and out of the influence of the late Early Cretaceous magmatism in the Bantimala and Barru Complexes, respectively. Felsic igneous activities are confirmed in the Late Cretaceous and the Eocene by the zircon U–Pb age of igneous rocks intruding or included as detrital fragments in three basement complexes. These dates are similar to those reported from the Meratus Complex of South Kalimantan. The detrital zircon age distributions of the basement rocks in the South Arm of Sulawesi display predominant Mesozoic (Cretaceous and Triassic) and Paleozoic populations with a small population of Proterozoic ages supporting the hypothesis that the West Sulawesi block originated from the region of the circum Bird's Head-Australian, namely the Inner Banda block. The absence of Jurassic zircon age population in the South Arm of Sulawesi suggests the division of the South Arm of Sulawesi from the Inner Banda block in early stage of rifting. Western Sulawesi is composed of several blocks separated from Inner Banda block with different histories, which is supported by the varieties of zircon population distribution in the basement rocks in the Western Sulawesi and also difference of general orientations of structural features between the Bantimala and Barru Complexes.

Total Mercury and Methylmercury Response in Water, Sediment, and Biota to Destratification of the Great Salt Lake, Utah, United States.

Measurements of chemical and physical parameters made before and after sealing of culverts in the railroad causeway spanning the Great Salt Lake in late 2013 documented dramatic alterations in the system in response to the elimination of flow between the Great Salt Lake's north and south arms. The flow of denser, more-saline water through the culverts from the north arm (Gunnison Bay) to the south arm (Gilbert Bay) previously drove the perennial stratification of the south arm and the existence of oxic shallow brine and anoxic deep brine layers. Closure of the causeway culverts occurred concurrently with a multiyear drought that resulted in a decrease in the lake elevation and a concomitant increase in top-down erosion of the upper surface of the deep brine layer by wind-forced mixing. The combination of these events resulted in the replacement of the formerly stratified water column in the south arm with one that was vertically homogeneous and oxic. Total mercury concentrations in the deep waters of the south arm decreased by approximately 81% and methylmercury concentrations in deep waters decreased by roughly 86% due to destratification. Methylmercury concentrations decreased by 77% in underlying surficial sediment, whereas there was no change observed in total mercury. The dramatic mercury loss from deep waters and methylmercury loss from underlying sediment in response to causeway sealing provides new understanding of the potential role of the deep brine layer in the accumulation and persistence of methylmercury in the Great Salt Lake. Additional mercury measurements in biota appear to contradict the previously implied connection between elevated methylmercury concentrations in the deep brine layer and elevated mercury in avian species reported prior to causeway sealing.

Estimated seepage rates from selected ditches, ponds, and lakes at the Camas National Wildlife Refuge, eastern Idaho

The Camas National Wildlife Refuge (Refuge) in eastern Idaho, established in 1937, contains wetlands, ponds, and wet meadows that are essential resting and feeding habitat for migratory birds and nesting habitat for waterfowl. Initially, natural sources of water supported these habitats. However, during the past few decades, changes in climate and surrounding land use have altered and reduced natural groundwater and surface-water inflows, resulting in a 5-meter decline in the water table and an earlier, and more frequent, occurrence of no flow in Camas Creek at the Refuge. Due to these changes in water availability, water management that includes extensive groundwater pumping is now necessary to maintain the wetlands, ponds, and wet meadows.These water management activities have proven to be inefficient and expensive, and the Refuge is seeking alternative water-management options that are more efficient and less expensive. More efficient water management at the Refuge may be possible through knowledge of the seepage rates from ditches, ponds, and lakes at the Refuge. With this knowledge, water-management efficiency may be improved by natural means through selective use of water bodies with the smallest seepage rates or through engineering efforts to minimize seepage losses from water bodies with the largest seepage rates.The U.S. Geological Survey performed field studies in 2015 and 2016 to estimate seepage rates for selected ditches, ponds, and lakes at the Refuge. Estimated seepage rates from ponds and lakes ranged over an order of magnitude, from 3.4 ± 0.2 to 103.0 ± 0.5 mm/d, with larger seepage rates calculated for Big Pond and Redhead Pond, intermediate seepage rates calculated for Two-way Pond, and smaller seepages rates calculated for the south arm of Sandhole Lake. Estimated seepage losses from two reaches of Main Diversion Ditch were 21 ± 2 and 17 ± 2 percent/km. These losses represent seepage rates of about 890 and 860 mm/d, which are one- to two-orders-of-magnitude larger than seepage rates from the ponds and lake.The depth-integrated vertical hydraulic conductivity (Kv) for sediment underlying the ponds and lake was the primary control of seepage rates. The Kv's were 30 and 34 m/d for Big Pond, 14 and 18 m/d for Toomey Pond, 8 and 10 m/d for Two-way Pond, and 47 m/d for the north arm of Sandhole Lake.

Microbialite response to an anthropogenic salinity gradient in Great Salt Lake, Utah.

A railroad causeway across Great Salt Lake, Utah (GSL), has restricted water flow since its construction in 1959, resulting in a more saline North Arm (NA; 24%-31% salinity) and a less saline South Arm (SA; 11%-14% salinity). Here, we characterized microbial carbonates collected from the SA and the NA to evaluate the effect of increased salinity on community composition and abundance and to determine whether the communities present in the NA are still actively precipitating carbonate or if they are remnant features from prior to causeway construction. SSU rRNA gene abundances associated with the NA microbialite were three orders of magnitude lower than those associated with the SA microbialite, indicating that the latter community is more productive. SSU rRNA gene sequencing and functional gene microarray analyses indicated that SA and NA microbialite communities are distinct. In particular, abundant sequences affiliated with photoautotrophic taxa including cyanobacteria and diatoms that may drive carbonate precipitation and thus still actively form microbialites were identified in the SA microbialite; sequences affiliated with photoautotrophic taxa were in low abundance in the NA microbialite. SA and NA microbialites comprise smooth prismatic aragonite crystals. However, the SA microbialite also contained micritic aragonite, which can be formed as a result of biological activity. Collectively, these observations suggest that NA microbialites are likely to be remnant features from prior to causeway construction and indicate a strong decrease in the ability of NA microbialite communities to actively precipitate carbonate minerals. Moreover, the results suggest a role for cyanobacteria and diatoms in carbonate precipitation and microbialite formation in the SA of GSL.

Polymetallic mineralisation associated with Carboniferous I-type granitoids in central Stewart Island, New Zealand

ABSTRACTCarboniferous granitoids in central Stewart Island host two metalliferous hydrothermal systems that formed during emplacement of the c. 306 ± 2 Ma old Euchre Pluton and 303 ± 2 Ma Hill 267 leucogranitoid, respectively. The Ogles Creek–Silvertown Hydrothermal System (OST) on the eastern side of South West Arm, Paterson Inlet is centred on the scheelite-bearing, ilmenite-syenogranite core of the Euchre Pluton. Here pyritic-potassic alteration and related veins contain Mo, Bi, Ag, Co, Cu, W, Pb, Zn, U–Th and rare Earth element (REE) sulphide, telluride, oxide and phosphate minerals. Peripheral quartz-rich veins contain various Ag, Au, Pb and Zn-bearing sulphide, telluride and oxide minerals. The Hill 267 Hydrothermal System (HHS) is centred on the ridge between the Scott Burn and Forked Creek where strongly altered leucogranitoid riddled with miarolitic cavities contains pyrite, W- and Nb-bearing rutile, molybdenite, tourmaline and 2–10 times background Bi, Ag, Te, Cu and Se. More prospective parts of both systems have probably been removed by erosion, but less deeply eroded correlative hydrothermal systems may be present elsewhere in New Zealand near the outboard margin of the Takaka Terrane.

Fish communities’ response to implementation of restoring measures in a highly artificialized estuary

Over the years, the Mondego estuary has undergone various anthropogenic impacts. One of the most serious was the closing of the communication between the two arms of the system (north and south), in the 1990s, which promoted eutrophication and a consequent water quality decline in the south arm. Several mitigation measures were subsequently implemented, in particular the re-establishing of the communication between the two arms in 2006, increasing water flow and reducing water residence time in the south arm. The present study aimed to evaluate the impact of management measures on the ecological and conservation condition of the Mondego estuary, through a longitudinal assessment of the structure and composition of the fish communities over a decade. The Mondego fish community showed important modifications over the years, in terms of structure, ecological quality and conservation value. The fish community status improved following the reconnection of both arms. In the south arm those changes appear to be more evident than in the other estuarine areas, where an inverse pattern was observed in the last few years. A redistribution of the fish species within the system may have been responsible for those unexpected alterations in the north arm and upstream area.

Cobertura florestal e qualidade da água na bacia hidrográfica do rio Jucu, estado do Espírito Santo, Brasil

Os fragmentos florestais remanescentes da mata atlântica influenciam indubitavelmente na qualidade da água dos rios que drenam. Objetivando analisar o percentual de cobertura florestal e os impactos antrópicos sobre os parâmetros de qualidade da água e compará-las em relação à resolução CONAMA no 357/2005, estudaram-se duas sub-bacias: rio Formate e rio Jucu Braço Sul, no qual pertencem a Bacia Hidrográfica do rio Jucu. Para subsidiar a discussão utilizou-se o IQA da CETESB e o Software ArcGIS 9.3 para elaborar a base de dados espaciais. Os resultados expõem que o Rio Jucu (Braço Sul) com 68% de cobertura florestal apresentou água com índice de qualidade “boa” em todos os pontos e o Formate com 41% de cobertura florestal entre “regular” e “ruim”. Destaca-se também que as variáveis que se apresentaram acima do limite estabelecido pela resolução CONAMA 357/2005 foram DBO5, Ptotal, Ntotal e Colifirmes Termotolerantes principalmente na sub-bacia do rio Jucu, que representam poluição antrópica. Por fim, o estudo aponta a influência do ambiente externo sobre a qualidade da água, relevando a importância da cobertura florestal como meio de proteção aos mananciais, e assim priorizar sua segurança hídrica.

How Do Changes to the Railroad Causeway in Utah’s Great Salt Lake Affect Water and Salt Flow?

Managing terminal lake elevation and salinity are emerging problems worldwide. We contribute to terminal lake management research by quantitatively assessing water and salt flow for Utah’s Great Salt Lake. In 1959, Union Pacific Railroad constructed a rock-filled causeway across the Great Salt Lake, separating the lake into a north and south arm. Flow between the two arms was limited to two 4.6 meter wide rectangular culverts installed during construction, an 88 meter opening (referred to locally as a breach) installed in 1984, and the semi porous material of the causeway. A salinity gradient developed between the two arms of the lake over time because the south arm receives approximately 95% of the incoming streamflow entering Great Salt Lake. The north arm is often at, or near, salinity saturation, averaging 317 g/L since 1966, while the south is considerably less saline, averaging 142 g/L since 1966. Ecological and industrial uses of the lake are dependent on long-term salinity remaining within physiological and economic thresholds, although optimal salinity varies for the ecosystem and between diverse stakeholders. In 2013, Union Pacific Railroad closed causeway culverts amid structural safety concerns and proposed to replace them with a bridge, offering four different bridge designs. As of summer 2015, no bridge design has been decided upon. We investigated the effect that each of the proposed bridge designs would have on north and south arm Great Salt Lake elevation and salinity by updating and applying US Geological Survey’s Great Salt Lake Fortran Model. Overall, we found that salinity is sensitive to bridge size and depth, with larger designs increasing salinity in the south arm and decreasing salinity in the north arm. This research illustrates that flow modifications within terminal lakes cannot be separated from lake salinity, ecology, management, and economic uses.

Santam and Nando's: An advertising narrative of local humour, local conflict, local co-branding

ABSTRACTIn 2011 South African short term insurer Santam (Santam Ltd.) put in place an advertising initiative that illustrates the power of a humorous brand narrative effected in conjunction with another brand. In this case, it is the South African arm of Nando's (Nando's Chickenland Ltd.), a fast food restaurant chain specialising in Portuguese-themed chicken dishes that rely heavily on peri-peri spices. The two well-known brands aired a series of five commercials on television and the Internet, trading good-humoured jibes centred around the value proposition of each company's offering. The resultant rise in social media viewership and consumer engagement was notable and illustrates the efficacy of a cobranded narrative run over numerous media platforms; in this case radio, television, social media, print and the Internet.

Petrology, geochemistry and tectonic significance of serpentinized ultramafic rocks from the South Arm of Sulawesi, Indonesia

Serpentinized ultramafic rocks occur in two separate basement complexes in the South Arm of Sulawesi, the Bantimala and Barru Blocks. We present petrographic, mineral chemical and geochemical data for these rocks, and interpret them in terms of petrogenesis and tectonic setting. The rocks of both blocks show strong serpentinization of original anhydrous silicates. The Bantimala ultramafics consist mainly of peridotite (harzburgite and dunite) and clinopyroxenite, with lenses of podiform chromitite. Metamorphism is evidenced by the occurrence of amphibolite-facies tremolite schist. In contrast, the Barru ultramafics consist of harzburgite peridotite and podiform chromitite, which also show an amphibolite-facies overprint that in this case may be related to intrusion by a large dacite/granodiorite body. Whole-rock trace element analyses and spinel compositions show that the Barru harzburgite is depleted relative to primitive mantle, and has had some melt extracted. In contrast, the Bantimala dunite, harzburgite and clinopyroxenite are cumulates. Both are derived from a supra-subduction zone environment, and were obducted during the closure of small back-arc basins. If there has been no rotation of the blocks, then the Bantimala ultramafics were emplaced from an ENE direction, while the Barru ultramafics were emplaced from the WNW. The ultramafic suites from these two blocks are juxtaposed with metamorphic assemblages, which were later intruded by younger volcanics, particularly in the Barru Block.