scholarly journals Thresholds of acidification impacts on macroinvertebrates adapted to seasonally acidified tropical streams: potential responses to extreme drought-driven pH declines

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11955
Author(s):  
Carissa Ganong ◽  
Minor Hidalgo Oconitrillo ◽  
Catherine Pringle
Keyword(s):  
Climate Change ◽  
Southern Oscillation ◽  
Tropical Streams ◽  
Ph Effects ◽  
Macroinvertebrate Communities ◽  
Neotropical Streams ◽  
Mesocosm Experiments ◽  
Stream Macroinvertebrate ◽  
Dry Seasons ◽  
Low Levels

Background Drought-driven acidification events of increasing frequency and severity are expected as a consequence of climate change, and these events may expose macroinvertebrate taxa to increased acidification beyond their tolerance levels. Recent work in lowland Costa Rica has shown that poorly-buffered tropical streams exhibit natural seasonal variation in pH, with extremely low levels (<4.5) after extreme dry seasons). Our goal was to determine the threshold of pH effects on survival of three tropical stream macroinvertebrate taxa. Methods We conducted laboratory mesocosm experiments to determine acidification effects (using diluted HCl) on three focal macroinvertebrate taxa collected from a poorly-buffered stream at La Selva Biological Station: (1) mayfly naiads (Ephemeroptera: Leptophlebiidae: Traverella holzenthali), (2) adult shrimp (Decapoda: Palaemonidae: Macrobrachium olfersii), and (3) larval midges (Diptera: Chironomidae). We also compared the effect of pH on survival and growth rates of larval midges from a poorly-buffered (pH 4.3–6.9) vs. a naturally well-buffered (pH 5.1–6.9) stream. Results/Discussion Mayfly and shrimp survival decreased between pH 4.0 and 3.5, overlapping with the range of lowest pH levels (3.6–4.0) recorded during a previous extreme El Niño Southern Oscillation event in 1998 and suggesting that increasingly extreme acidification events induced by climate change may negatively affect their survival. In contrast, survival of larval midges was unaffected by pH regimes at/above 3.5, indicating tolerance to pH levels experienced in poorly-buffered stream during seasonal acidification, which has presumably occurred over millennia. These findings highlight the potential importance of historical pH regimes in structuring macroinvertebrate communities. These results are relevant not only to lowland Neotropical streams, but also signal the need for further research in lotic ecosystems worldwide where drought-driven pH declines have been documented or are probable in the future.

VARIABILIDAD CLIMÁTICA, CAMBIO CLIMÁTICO Y PESQUERÍAS EN EL ECUADOR.

2012 ◽  
Vol 1 (1) ◽  
Author(s):  
Johnny Chavarría Viteri ◽  
Dennis Tomalá Solano
Keyword(s):  
Climate Change ◽  
Climate Variability ◽  
Pacific Decadal Oscillation ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Current Action ◽  
Palabras Clave

La variabilidad climática es la norma que ha modulado la vida en el planeta. Este trabajo demuestra que las pesquerías y acuicultura costera ecuatorianas no son la excepción, puesto que tales actividades están fuertemente influenciadas por la variabilidad ENSO (El Niño-Oscilación del Sur) y PDO (Oscilación Decadal del Pacífico), planteándose que la señal del cambio climático debe contribuir a esta influencia. Se destaca también que, en el análisis de los efectos de la variabilidad climática sobre los recursos pesqueros, el esfuerzo extractivo también debe ser considerado. Por su parte, la acción actual de la PDO está afectando la señal del cambio climático, encontrándose actualmente en fases opuestas. Se espera que estas señales entren en fase a finales de esta década, y principalmente durante la década de los 20 y consecuentemente se evidencien con mayor fuerza los efectos del Cambio Climático. Palabras Clave: Variabilidad Climática, Cambio Climático, ENSO, PDO, Pesquerías, Ecuador. ABSTRACT Climate variability is the standard that has modulated life in the planet. This work shows that the Ecuadorian  fisheries and aquaculture are not the exception, since such activities are strongly influenced by ENSO variability (El Niño - Southern Oscillation) and PDO (Pacific Decadal Oscillation), considering that the signal of climate change should contribute to this influence. It also emphasizes that in the analysis of the effects of climate variability on the fishing resources, the extractive effort must also be considered. For its part, the current action of the PDO is affecting the signal of climate change, now found on opposite phases. It is hoped that these signals come into phase at the end of this decade, and especially during the decade of the 20’s and more strongly evidencing the effects of climate change. Keywords: Climate variability, climate change, ENSO (El Niño - Southern Oscillation) and PDO  (Pacific Decadal Oscillation); fisheries, Ecuador. Recibido: mayo, 2012Aprobado: agosto, 2012

Twelfth Century AD

2017 ◽  
Author(s):  
Lonnie G. Thompson ◽  
Alan L. Kolata
Keyword(s):  
Climate Change ◽  
Southern Oscillation ◽  
Sediment Cores ◽  
Critical Role ◽  
Lake Titicaca ◽  
Independent Evidence ◽  
Tropical Regions ◽  
Ice Cap ◽  
Paleoclimate Records ◽  
Past Climate Change

Climate is a fundamental and independent variable of human existence. Given that 50 percent of the Earth’s surface and much of its population exist between 30oN and 30oS, paleoenvironmental research in the Earth’s tropical regions is vital to our understanding of the world’s current and past climate change. Most of the solar energy that drives the climate system is absorbed in these regions. Paleoclimate records reveal that tropical processes, such as variations in the El Niño-Southern Oscillation (ENSO), have affected the climate over much of the planet. Climatic variations, particularly in precipitation and temperature, play a critical role in the adaptations of agrarian cultures located in zones of environmental sensitivity, such as those of the coastal deserts, highlands, and altiplano of the Andean region. Paleoclimate records from the Quelccaya ice cap (5670 masl) in highland Peru that extend back ~1800 years show good correlation between precipitation and the rise and fall of pre-Hispanic civilizations in western Peru and Bolivia. Sediment cores extracted from Lake Titicaca provide independent evidence of this correspondence with particular reference to the history of the pre-Hispanic Tiwanaku state centered in the Andean altiplano. Here we explore, in particular, the impacts of climate change on the development and ultimate dissolution of this altiplano state.

scholarly journals Effects of multiple stressors associated with agriculture on stream macroinvertebrate communities in a tropical catchment

PLoS ONE ◽  
2019 ◽  
Vol 14 (8) ◽  
pp. e0220528 ◽  
Author(s):  
Aydeé Cornejo ◽  
Alan M. Tonin ◽  
Brenda Checa ◽  
Ana Raquel Tuñon ◽  
Diana Pérez ◽  
...  
Keyword(s):  
Multiple Stressors ◽  
Macroinvertebrate Communities ◽  
Stream Macroinvertebrate

scholarly journals Contrasting capabilities of two ungulate species to cope with extremes of aridity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Melinda Boyers ◽  
Francesca Parrini ◽  
Norman Owen-Smith ◽  
Barend F. N. Erasmus ◽  
Robyn S. Hetem
Keyword(s):  
Climate Change ◽  
High Water ◽  
Future Climate Change ◽  
Body Temperatures ◽  
Wet Season ◽  
Trade Off ◽  
Ambient Temperatures ◽  
Mammalian Herbivores ◽  
Dry Seasons ◽  
Connochaetes Taurinus

AbstractSouthern Africa is expected to experience increased frequency and intensity of droughts through climate change, which will adversely affect mammalian herbivores. Using bio-loggers, we tested the expectation that wildebeest (Connochaetes taurinus), a grazer with high water-dependence, would be more sensitive to drought conditions than the arid-adapted gemsbok (Oryx gazella gazella). The study, conducted in the Kalahari, encompassed two hot-dry seasons with similar ambient temperatures but differing rainfall patterns during the preceding wet season. In the drier year both ungulates selected similar cooler microclimates, but wildebeest travelled larger distances than gemsbok, presumably in search of water. Body temperatures in both species reached lower daily minimums and higher daily maximums in the drier season but daily fluctuations were wider in wildebeest than in gemsbok. Lower daily minimum body temperatures displayed by wildebeest suggest that wildebeest were under greater nutritional stress than gemsbok. Moving large distances when water is scarce may have compromised the energy balance of the water dependent wildebeest, a trade-off likely to be exacerbated with future climate change.

scholarly journals Effect of environmental history on the habitat-forming kelp Macrocystis pyrifera responses to ocean acidification and warming: a physiological and molecular approach

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pamela A. Fernández ◽  
Jorge M. Navarro ◽  
Carolina Camus ◽  
Rodrigo Torres ◽  
Alejandro H. Buschmann
Keyword(s):  
Climate Change ◽  
Ocean Acidification ◽  
Environmental History ◽  
Coastal Upwelling ◽  
Macrocystis Pyrifera ◽  
Natural Variability ◽  
Kelp Forests ◽  
Species Response ◽  
Enhanced Expression ◽  
Mesocosm Experiments

AbstractThe capacity of marine organisms to adapt and/or acclimate to climate change might differ among distinct populations, depending on their local environmental history and phenotypic plasticity. Kelp forests create some of the most productive habitats in the world, but globally, many populations have been negatively impacted by multiple anthropogenic stressors. Here, we compare the physiological and molecular responses to ocean acidification (OA) and warming (OW) of two populations of the giant kelp Macrocystis pyrifera from distinct upwelling conditions (weak vs strong). Using laboratory mesocosm experiments, we found that juvenile Macrocystis sporophyte responses to OW and OA did not differ among populations: elevated temperature reduced growth while OA had no effect on growth and photosynthesis. However, we observed higher growth rates and NO3− assimilation, and enhanced expression of metabolic-genes involved in the NO3− and CO2 assimilation in individuals from the strong upwelling site. Our results suggest that despite no inter-population differences in response to OA and OW, intrinsic differences among populations might be related to their natural variability in CO2, NO3− and seawater temperatures driven by coastal upwelling. Further work including additional populations and fluctuating climate change conditions rather than static values are needed to precisely determine how natural variability in environmental conditions might influence a species’ response to climate change.

scholarly journals The effects of ENSO, climate change and human activities on the water level of Lake Toba, Indonesia: a critical literature review

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Hendri Irwandi ◽  
Mohammad Syamsu Rosid ◽  
Terry Mart
Keyword(s):  
Climate Change ◽  
Water Level ◽  
Human Activities ◽  
Southern Oscillation ◽  
Climatic Conditions ◽  
Water Levels ◽  
Dominant Factor ◽  
Climate Projections ◽  
Continuous Increase ◽  
The Future

AbstractThis research quantitatively and qualitatively analyzes the factors responsible for the water level variations in Lake Toba, North Sumatra Province, Indonesia. According to several studies carried out from 1993 to 2020, changes in the water level were associated with climate variability, climate change, and human activities. Furthermore, these studies stated that reduced rainfall during the rainy season due to the El Niño Southern Oscillation (ENSO) and the continuous increase in the maximum and average temperatures were some of the effects of climate change in the Lake Toba catchment area. Additionally, human interventions such as industrial activities, population growth, and damage to the surrounding environment of the Lake Toba watershed had significant impacts in terms of decreasing the water level. However, these studies were unable to determine the factor that had the most significant effect, although studies on other lakes worldwide have shown these factors are the main causes of fluctuations or decreases in water levels. A simulation study of Lake Toba's water balance showed the possibility of having a water surplus until the mid-twenty-first century. The input discharge was predicted to be greater than the output; therefore, Lake Toba could be optimized without affecting the future water level. However, the climate projections depicted a different situation, with scenarios predicting the possibility of extreme climate anomalies, demonstrating drier climatic conditions in the future. This review concludes that it is necessary to conduct an in-depth, comprehensive, and systematic study to identify the most dominant factor among the three that is causing the decrease in the Lake Toba water level and to describe the future projected water level.

scholarly journals Monitoring of Neotropical Streams Using Macroinvertebrate Communities: Evidence from Honduras

Environments ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 27
Author(s):  
Stefano Fenoglio ◽  
Alberto Doretto
Keyword(s):  
Water Quality ◽  
Working Party ◽  
Biological Indicators ◽  
Environmental Conservation ◽  
Taxon Richness ◽  
Macroinvertebrate Communities ◽  
Class A ◽  
Neotropical Streams ◽  
Local Contribution ◽  
Level Identification

Assessing the water quality by using biological indicators is a reliable and economically feasible way to promote environmental conservation in developing tropical countries. Here, we report one of the few examples of river biomonitoring in Honduras. In June 2005, benthic macroinvertebrates were collected from six sites in the Río Cangrejal basin. An adapted version of the Biological Monitoring Working Party index (BMWP) was used to assess the water quality because it is simple, consolidated, relatively easy to use, and needs a family-level identification. Moreover, two other community metrics were calculated, namely the total taxon richness and local contribution to beta diversity (LCBD). Differences in the biomonitoring and diversity metrics among sites and their correlations were statistically tested. Thirty-nine macroinvertebrate taxa were collected and, despite significant differences in the BMWP score, all sampling sites were classified in the high environmental quality class. A very strong and positive correlation between the BMPW and taxon richness was found, while LCBD did not vary significantly and did not correlate with the other metrics. Our results suggest that taxon richness could be used as a surrogate indicator to assess the water quality when consolidate biomonitoring methods are not available.

scholarly journals Morphodynamic Controls for Growth and Evolution of a Rubble Coral Island

2021 ◽  
Vol 13 (8) ◽  
pp. 1582
Author(s):  
Lara Talavera ◽  
Ana Vila-Concejo ◽  
Jody M. Webster ◽  
Courtney Smith ◽  
Stephanie Duce ◽  
...  
Keyword(s):  
Climate Change ◽  
Southern Oscillation ◽  
Small Island ◽  
Change Scenario ◽  
Remotely Sensed Data ◽  
Island Growth ◽  
Wave Interactions ◽  
Tree Island ◽  
Coral Island ◽  
Alongshore Sediment Transport

Rubble islands are dynamic sedimentary features present on reef platforms that evolve under a variety of morphodynamic processes and controlling mechanisms. They provide valuable inhabitable land for small island nations, critical habitat for numerous species, and are threatened by climate change. Aiming to investigate the controlling mechanisms dictating the evolution of One Tree Island (OTI), a rubble island in the Southern Great Barrier Reef, we combined different remotely-sensed data across varying timescales with wave data extracted from satellite altimetry and cyclone activity. Our findings show that (1) OTI had expanded by 7% between 1978 and 2019, (2) significant gross planform decadal adjustments were governed by the amount, intensity, proximity, and relative position of cyclones as well as El Niño Southern Oscillation (ENSO) phases, and (3) the mechanisms of island growth involve rubble spits delivering and redistributing rubble to the island through alongshore sediment transport and wave overtopping. Frequent short-term monitoring of the island and further research coupling variations in the different factors driving island change (i.e., sediment availability, reef-wave interactions, and extreme events) are needed to shed light on the future trajectory of OTI and other rubble islands under a climate change scenario.

scholarly journals Responses of Benthic Macroinvertebrate Communities of Two Tropical, High-Mountain Lakes to Climate Change and Deacidification

Diversity ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 243
Author(s):  
Javier Alcocer ◽  
Luis A. Oseguera ◽  
Diana Ibarra-Morales ◽  
Elva Escobar ◽  
Lucero García-Cid
Keyword(s):  
Climate Change ◽  
Species Richness ◽  
Water Temperature ◽  
Water Level ◽  
Environmental Changes ◽  
Mountain Lakes ◽  
High Mountain ◽  
Macroinvertebrate Communities ◽  
High Mountain Lakes ◽  
La Luna

High-mountain lakes are among the most comparable ecosystems globally and recognized sentinels of global change. The present study pursued to identify how the benthic macroinvertebrates (BMI) communities of two tropical, high mountain lakes, El Sol and La Luna, Central Mexico, have been affected by global/regional environmental pressures. We compared the environmental characteristics and the BMI communities between 2000–2001 and 2017–2018. We identified three principal environmental changes (the air and water temperature increased, the lakes’ water level declined, and the pH augmented and became more variable), and four principal ecological changes in the BMI communities [a species richness reduction (7 to 4), a composition change, and a dominant species replacement all of them in Lake El Sol, a species richness increase (2 to 4) in Lake La Luna, and a drastic reduction in density (38% and 90%) and biomass (92%) in both lakes]. The air and water temperature increased 0.5 °C, and lakes water level declined 1.5 m, all suggesting an outcome of climate change. Contrarily to the expected acidification associated with acid precipitation, both lakes deacidified, and the annual pH fluctuation augmented. The causes of the deacidification and the deleterious impacts on the BMI communities remained to be identified.

scholarly journals The Productive Landscape in the Desert Margin for the Sustainable Development of Rural Settlements: An Innovative Greenbelt for Maranjab Desert in Iran

2021 ◽  
Vol 13 (4) ◽  
pp. 2077
Author(s):  
Mahnaz Sarlak ◽  
Laura Valeria Ferretti ◽  
Rita Biasi
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Low Cost ◽  
Agricultural Systems ◽  
Rural Settlements ◽  
Green Belt ◽  
The Sustainable Development ◽  
Research Questions ◽  
New Form ◽  
Low Levels

About two billion rural individuals depend on agricultural systems associated with a high amount of risk and low levels of yield in the drylands of Asia, Africa, and Latin America. Human activities, climate change and natural extreme events are the most important drivers of desertification. This phenomenon has occurred in many regions of Iran, particularly in the villages in the periphery of the central desert of Iran, and has made living in the oases so difficult that the number of abandoned villages is increasing every year. Land abandonment and land-use change increase the risk of desertification. This study aims to respond to the research questions: (i) does the planning of green infrastructures on the desert margin affect the distribution and balance of the population? (ii) how should the green belt be designed to have the greatest impact on counteracting desertification?, and (iii) does the design of productive landscape provide the solution? Through a wide-ranging and comprehensive approach, this study develops different scenarios for designing a new form of green belt in order to sustainably manage the issues of environmental protection, agricultural tradition preservation and desertification counteraction. This study proposes a new-traditional greenbelt including small low-cost and low-tech projects adapted to rural scale.

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