scholarly journals Páramo Lakes of Colombia: An Overview of Their Geographical Distribution and Physicochemical Characteristics

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2175
Author(s):  
Angela Zapata ◽  
Carlos A. Rivera-Rondón ◽  
Daivan Valoyes ◽  
Claudia L. Muñoz-López ◽  
Marino Mejía-Rocha ◽  
...  
Keyword(s):  
Water Chemistry ◽  
Water Source ◽  
Landscape Fragmentation ◽  
Physicochemical Characteristics ◽  
Neotropical Region ◽  
Low Oxygen ◽  
The Andes ◽  
Bedrock Geology ◽  
High Nutrient ◽  
Local Pressures

The páramo lakes, Colombia, situated in the neotropical region, are of great value both as natural heritage and as water source to the most populated areas of the Andes, but are threatened by expanding agriculture, livestock, mining, and landscape fragmentation. Nonetheless, a general assessment of the lakes’ distribution and biogeochemical characteristics was lacking. We made a complete inventory of the Colombian páramo lakes and characterized their morphometry and water chemistry based on a survey of 51 lakes in the Eastern Cordillera. There are 3250 lakes distributed across 28 páramo complexes in Colombia, mainly located between 3600 and 4400 m a.s.l. The lakes are usually small (<10 ha) and shallow (<10 m). Most of them are slightly acidic (average pH~6), with high nutrient (total phosphorus ~0.6 mg/L, total nitrogen ~1 mg/L) and total organic carbon (~6 mg/L) concentrations and low oxygen (~3.5 mg/L) at the bottom. Water chemistry varies according to two main independent gradients related to watershed bedrock geology and trophic state. Global change pressures may be challenging the preservation of these unique ecosystems. Increasing the protection of more lake watersheds should reduce these potential impacts by mitigating negative synergies with local pressures.

Circulation and water mass characteristics of the southern Great Barrier Reef

1994 ◽  
Vol 45 (1) ◽  
pp. 1 ◽  
Author(s):  
JH Middleton ◽  
P Coutis ◽  
DA Griffin ◽  
A Macks ◽  
A McTaggart ◽  
...  
Keyword(s):  
Great Barrier Reef ◽  
Heat Loss ◽  
Barrier Reef ◽  
Low Oxygen ◽  
Geostrophic Balance ◽  
Shelf Slope ◽  
High Nutrient ◽  
Slope Currents ◽  
North And South ◽  
Upper Slope

Data acquired during a winter (May) cruise of the RV Franklin to the southern Great Barrier Reef indicate that the dynamics of the shelf/slope region are governed by the tides, the poleward-flowing East Australian Current (EAC), and the complex topography. Over the Marion Plateau in water deeper than - 100 m, the EAC appears to drive a slow clockwise circulation. Tides appear to be primarily responsible for shelf/slope currents in the upper layers, with evidence of nutrient uplift from the upper slope to the outer shelf proper in the Capricorn Channel. Elsewhere, the bottom Ekrnan flux of the strongly poleward-flowing EAC enhances the sloping isotherms associated with the longshore geostrophic balance, pumping nutrient-rich waters from depth to the upper continental slope. Generally, shelf waters are cooler than oceanic waters as a consequence of surface heat loss by radiation. A combination of heat loss and evaporation from waters flowing in the shallows of the Great Sandy Strait appears to result in denser 'winter mangrove waters' exporting low-oxygen, high-nutrient waters onto the shelf both north and south of Fraser Island; these subsequently mix with shelf waters and finally flow offshore at - 100 m depth, just above the salinity-maximum layer, causing anomalous nutrient values in the region of Fraser Island.

scholarly journals Probing the Effect of Water Recycling on Flotation through Anion Spiking Using a Low-Grade Cu–Ni–PGM Ore: The Effect of NO3−, SO42− and S2O32−

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 340
Author(s):  
Mathew Dzingai ◽  
Malibongwe S. Manono ◽  
Kirsten C. Corin
Keyword(s):  
Water Chemistry ◽  
Froth Flotation ◽  
Water Source ◽  
Threshold Concentration ◽  
Process Water ◽  
Low Grade ◽  
Unit Operations ◽  
Flotation Performance ◽  
Anion Distribution ◽  
Nickel Grade

Water scarcity necessitates the recycling of process water within mineral processing practices. This may however come with its disadvantages for unit operations such as froth flotation as this process is water intensive and sensitive to water chemistry. It is therefore important to monitor the water chemistry of the recycle stream of process water and any other water source to flotation. Monitoring the concentrations of the anions in recycled process water is therefore important to consider as these are speculated to impact flotation performance. Batch flotation tests were conducted using synthetically prepared plant water (3 SPW) with a TDS of 3069 mg/L as the baseline experiment. 3 SPW contained 528 mg/LNO3− and 720 mg/L SO42−, other anions and cations, and no S2O32−. Upon spiking 3 SPW with selected anions, viz, NO3−, SO42− and S2O32−, it was noted that NO3− and SO42− exhibited threshold concentrations while S2O32− did not show a threshold concentration for both copper and nickel grade. Spiking 3 SPW with 352 mg/L more of NO3− to a total 880 mg/L NO3− concentration resulted in the highest copper and nickel grade compared to 3 SPW while increasing the S2O32− from 60 to 78 mg/L increased nickel and copper grade. 720 to 1200 mg/L SO42− and 528 to 880 mg/L NO3− were deemed the concentration boundaries within which lies the threshold concentration above which flotation performance declines with respect to metal grades, while for S2O32− the threshold concentration lies outside the range considered for this study. Anion distribution between the pulp and the froth did not seem to impact the recovery of copper or nickel. Notably, the correlation between the concentrate grades and anion distribution between the froth and the pulp seemed to be ion dependent.

Nutrients, Chlorophyll, and Internal Tides in the St. Lawrence Estuary

1976 ◽  
Vol 33 (12) ◽  
pp. 2747-2757 ◽  
Author(s):  
Jean-Claude Therriault ◽  
Guy Lacroix
Keyword(s):  
Surface Waters ◽  
Internal Tides ◽  
Upstream Region ◽  
Mixing Process ◽  
Low Oxygen ◽  
Lawrence Estuary ◽  
Deep Waters ◽  
High Nutrient ◽  
Phosphate Nitrate ◽  
St Lawrence Estuary

Tide-dependent variations of temperature, salinity, dissolved oxygen, phosphate, nitrate, and chlorophyll a support the existence of internal tides (longitudinal and transversal) in the St. Lawrence estuary. Vertical oscillations of the poorly oxygenated and nutrient-rich intermediate and deep waters of the estuary have been documented at the head of the Laurentian Channel, the region in which the internal tides are thought to be generated. Penetration of intermediate waters (high-nutrient and low-oxygen concentrations) beyond the Laurentian Channel associated with the internal tides and linked with an intense mixing process in the upstream region permits the nutrient enrichment of the surface waters and their eventual advection in the seaward direction.

Stimulation of Plasma Thyroxine Levels by Novel Water Chemistry during Smoltification in Chinook Salmon (Oncorhynchus tshawytscha)

1990 ◽  
Vol 47 (8) ◽  
pp. 1513-1517 ◽  
Author(s):  
Timothy L. Hoffnagle ◽  
Albert J. Fivizzani
Keyword(s):  
Water Chemistry ◽  
Flow Rate ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Water Source ◽  
Control Fish ◽  
Exposed Fish ◽  
Freshwater Population ◽  
Artificial Photoperiod ◽  
Stimulation Of

The separate influences of changes in water chemistry and flow rate on plasma thyroxine levels were assessed in a freshwater population of chinook salmon (Oncorhynchus tshawytscha) undergoing smoltification. Fish subjected to a change in water source had plasma thyroxine levels significantly greater than those of controls on several sampling dates. Maximum levels were observed 10 d after water change. Conversely, plasma thyroxine levels in fish for which the flow rate was increased showed little change and were never significantly different from controls. Plasma thyroxine levels were greater in fish held under a natural rather than artificial photoperiod but the patterns of change were similar in the two groups. Control fish transported to a new hatchery and novel water source attained plasma thyroxine levels which were even greater than those of novel water-exposed fish at the original hatchery. The results indicated that altered water chemistry rather than increased flow rate was the stimulus for the elevation in plasma thyroxine levels associated with smoltification in these chinook salmon.

A new species of Imparfinis Eigenmann & Norris, 1900 (Siluriformes: Heptapteridae) from the Tapajós basin, Brazil

Zootaxa ◽  
2019 ◽  
Vol 4701 (5) ◽  
pp. 461-472
Author(s):  
ÍTHALO DA SILVA CASTRO ◽  
WOLMAR BENJAMIN WOSIACKI
Keyword(s):  
New Species ◽  
Neotropical Region ◽  
Valid Species ◽  
Distal Margin ◽  
Caudal Peduncle ◽  
The Andes ◽  
Brown Band ◽  
Northern Brazil ◽  
Uruguay River ◽  
A New Species

Imparfinis comprises 20 valid species in the Heptapteridae, being the most diverse taxonomic group of catfishes of the Nemuroglanis subclade. The genus has one of the widest geographical distributions in the neotropical region, found on both sides of the Andes, from Costa Rica to the Paraná and Uruguay river basins in Argentina. A new species of Imparfinis is described from streams of the upper Rio Tapajós and its tributary Teles Pires in northern Brazil. The new species is diagnosed from all congeners by the presence of a vertical dark brown band W-shaped at the base of the caudal-fin rays, a thick dark brown lateral stripe from the snout to the end of the caudal peduncle, dark brown head, long maxillary barbel surpassing the distal margin of the pectoral fin, and presence of 39 or 40 total vertebrae. 

scholarly journals Lymnaea viatrix and Lymnaea columella in the neotropical region: a distributional outline

1982 ◽  
Vol 77 (2) ◽  
pp. 181-188 ◽  
Author(s):  
W. Lobato Paraense
Keyword(s):  
Puerto Rico ◽  
Costa Rica ◽  
South America ◽  
Dominican Republic ◽  
Neotropical Region ◽  
Southern South America ◽  
Negro River ◽  
The Andes ◽  
The Guianas ◽  
Northeastern Argentina

A review of lymnaeid samples collected by the author from 106 localities in Mexico, Cuba, Jamaica, Haiti, Dominican Republic, Puerto Rico, Martinique, Saint Lucia, Guatemala, Costa Rica, Panamá, Ecuador, Peru, Bolivia, Chile, Argentina, Uruguay andBrazil showed that one of them (from Ecuador) belonged to Lymnaea cousini Jousseaume, 1887, and all the others to either L. viatrix Orbigny, 1835 or l. columella Say, 1817. The ranges of L. viatrix and L. columella overlap in Middle America, and in northern and southern South America (Venezuela-Colombia-Ecuador and northeastern Argentina-Uruguay-southernmost Brazil, respectively). L. viatrix was the only species found in Peru west of the Andes and in Chile, and is supposed to have migrated eastward to Argentina via the Negro river basin. The range of L. columella in South America is discontinuous. The species has been recorded from Venezuela, Colombia and Ecuador and, east of the Andes, from latitudes 15º S (central-west Brazil) to 35º S (La Plata, Argentina). Such a gap may be attributed to either introduction from the northern into the southern area, or migration along the unsampled region on the eastern side of the Andes, or extinction in the now vacant area. No lymnaeids have been found so far in Brazil north of latitude 15º S and in the Guianas.

scholarly journals Ecological Analyses of Mycobacteria in Showerhead Biofilms and Their Relevance to Human Health

mBio ◽  
2018 ◽  
Vol 9 (5) ◽  
Author(s):  
Matthew J. Gebert ◽  
Manuel Delgado-Baquerizo ◽  
Angela M. Oliverio ◽  
Tara M. Webster ◽  
Lauren M. Nichols ◽  
...  
Keyword(s):  
Public Health ◽  
United States ◽  
Water Chemistry ◽  
Distribution Systems ◽  
Water Source ◽  
The United States ◽  
Environmental Predictors ◽  
Emerging Pathogens ◽  
Household Location ◽  
Lung Infections

ABSTRACTBacteria within the genusMycobacteriumcan be abundant in showerheads, and the inhalation of aerosolized mycobacteria while showering has been implicated as a mode of transmission in nontuberculous mycobacterial (NTM) lung infections. Despite their importance, the diversity, distributions, and environmental predictors of showerhead-associated mycobacteria remain largely unresolved. To address these knowledge gaps, we worked with citizen scientists to collect showerhead biofilm samples and associated water chemistry data from 656 households located across the United States and Europe. Our cultivation-independent analyses revealed that the genusMycobacteriumwas consistently the most abundant genus of bacteria detected in residential showerheads, and yet mycobacterial diversity and abundances were highly variable. Mycobacteria were far more abundant, on average, in showerheads receiving municipal water than in those receiving well water and in U.S. households than in European households, patterns that are likely driven by differences in the use of chlorine disinfectants. Moreover, we found that water source, water chemistry, and household location also influenced the prevalence of specific mycobacterial lineages detected in showerheads. We identified geographic regions within the United States where showerheads have particularly high abundances of potentially pathogenic lineages of mycobacteria, and these “hot spots” generally overlapped those regions where NTM lung disease is most prevalent. Together, these results emphasize the public health relevance of mycobacteria in showerhead biofilms. They further demonstrate that mycobacterial distributions in showerhead biofilms are often predictable from household location and water chemistry, knowledge that advances our understanding of NTM transmission dynamics and the development of strategies to reduce exposures to these emerging pathogens.IMPORTANCEBacteria thrive in showerheads and throughout household water distribution systems. While most of these bacteria are innocuous, some are potential pathogens, including members of the genusMycobacteriumthat can cause nontuberculous mycobacterial (NTM) lung infection, an increasing threat to public health. We found that showerheads in households across the United States and Europe often harbor abundant mycobacterial communities that vary in composition depending on geographic location, water chemistry, and water source, with households receiving water treated with chlorine disinfectants having particularly high abundances of certain mycobacteria. The regions in the United States where NTM lung infections are most common were the same regions where pathogenic mycobacteria were most prevalent in showerheads, highlighting the important role of showerheads in the transmission of NTM infections.

scholarly journals Apu, a new genus of Euchromiina (Lepidoptera: Erebidae: Arctiinae: Arctiini), and a new species from the montane forests of southeastern Peru

2021 ◽  
Vol 47 (3) ◽  
pp. 639-648
Author(s):  
Juan Grados
Keyword(s):  
New Species ◽  
Male Genitalia ◽  
New Genus ◽  
Morphological Characters ◽  
Neotropical Region ◽  
Montane Forests ◽  
Diagnostic Characters ◽  
The Andes ◽  
A New Species

Based on external morphological characters and the structure of the male genitalia, a new genus of Euchromiina from the Neotropical region, Apu gen. nov. is described. A new species is described, Apu mooreorum sp. nov. and the species Apu flavicornis (Druce) comb. nov. is redescribed. The genus occurs in the montane forests of the Andes. Diagnostic characters are provided for the genus and the two species which comprise it. Photographs of the adults of both species are provided, as well as the morphological characters of the male genitalia.

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