Posts by Yuanrong Zhou

Prehistoric Glaciation Influenced Frog Evolution

Posted by on Jun 23, 2015 in All Posts, Featured Posts, Science | 1 comment

Prehistoric Glaciation Influenced Frog Evolution

Spread the News:ShareExtensive studies in continental regions have discovered that climate variations can have strong impacts on the distribution and evolutionary history of species. Now, a study of mountainous areas, where few studies have been conducted, has found similar patterns in the current distribution and population isolation of a frog species on the Tibetan Plateau. The study, published in Scientific Reports by Jun Liu, of the Institute of Zoology, Chinese Academy of Sciences, and his colleagues looked at how historical processes might play the role in contemporary geographic distributions of frogs, a concept they refer to as phylogeography. Researchers discovered that ancient climate change impacted the demographic history of Nanorana parkeri, a frog species on the Tibetan Plateau, by facilitating population divergence. Nanorana parkeri, also known as the High Himalaya Frog, is a frog species only found in the southern Tibetan Plateau with an altitudinal range of 2850 to 4700 meters above sea level. No other frog species lives in altitudes as high as N. parkeri. Despite its limited geographical distribution, this medium-sized frog is very common in high-altitude grasslands, forests, marshes, and streams in the plateau. The varying topography, complex drainage system as well as high peaks make the region a biodiversity hotspot, where endemic species including N. parkeri can be spotted. The researchers analyzed the sequences of one mitochondria and three nuclear DNA from N. parkeri to investigate the genetic diversity of this frog. The species distribution modeling was applied to examine whether this species survived locally during the Pleistocene glaciations and how the recolonization process was during postglacial times. Through their analysis, the researchers discovered that there were two distinct lineages of this one frog species, East and West. More importantly, there was no overlap between these two lineages. Researchers estimated that this divergence in lineages may have occurred during the Middle Pleistocene, about 1.4 to 3.7 million years ago. The divergence occurred long before the Last Glacial Maximum (LGM), which was 0.72 to 0.5 million years ago. This indicates that the genetic lineages survived during the maximum glaciation in glacial refugia. During LGM, ice sheets covered much of North America, northern Europe, and Asia, including the Tibetan Plateau. Moreover, multiple refugia must have been existed for N. parkeri; otherwise, the genes would be mixed if the lineages were living in a single refuge. The researchers suggest that the Yarlung Zangbo valley in eastern region and the Kyichu catchment in the west might have been the refugia for the two lineages during historical glaciations. The researchers also proposed that other climatic factors might have affected this historical divergence as well. They found that the boundary between the two lineages coincides with the 400mm annual precipitation level. The eastern region is relatively humid while the western region is more arid and drier. The shift in climatic factors might act as a barrier to the dispersal of the frog. Although the frog is currently abundant, this study could have implications for conservation of frog species on the Tibetan Plateau. The two N. parkeri lineages have diverged for a long time with limited gene flow between them. Therefore, they each need to be protected separately. As a potential refugia for the frog, the Yarlung Zangbo valley and Kyichu catchment need to be conserved. Spread the...

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Roundup: Climate Science and International Adaptation

Posted by on Jun 8, 2015 in Adaptation, All Posts, Art/Culture, Featured Posts, Roundup, Science | 0 comments

Roundup: Climate Science and International Adaptation

Spread the News:ShareIntegration of Glacier and Snow “Energy budget-based distributed modeling of snow and glacier melt runoff is essential in a hydrologic model to accurately describe hydrologic processes in cold regions and high-altitude catchments. We developed herein an integrated modeling system with an energy budget-based multilayer scheme for clean glaciers, a single-layer scheme for debris-covered glaciers, and multilayer scheme for seasonal snow over glacier, soil, and forest within a distributed biosphere hydrological modeling framework.” Read more of the article here.   Climate Science on Glaciers “The 2001–2013 sum of positive temperatures (SPT) record, as a proxy of snow/ice ablation, has been obtained for the high-mountain glaciarized Munku-Sardyk massif, East Sayan Mountains, using daily NCEP/NCAR reanalysis data. The SPT (and ice melt) demonstrates a significant decreasing trend, with the highest values in 2001, 2002, and 2007, and the lowest in 2013. We have investigated relationships between potential summer ablation and synoptic-scale conditions over the study area.” Read more of this article here. International Adaptation to Glacier Retreat “The transboundary Himalayan Rivers flowing through Bhutan to India and Bangladesh constitute an enormous asset for economic development in a region which contains the largest number of poor people in the world. However, the rapid retreat of Himalayan glaciers has made South Asia vulnerable to variety of water-related natural hazards and disasters such as floods, landslides, and glacial lake outburst.” Read more of this book chapter here. Spread the...

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Glacial Retreat Encourages Seaweed Colonization

Posted by on May 26, 2015 in All Posts, Featured Posts, Science | 0 comments

Glacial Retreat Encourages Seaweed Colonization

Spread the News:ShareNewly ice-free areas exposed by glacial retreat in Potter Cove, Antarctica, are being colonized by seaweed. With glaciers melting, the original white, mostly lifeless Antarctica is now becoming darker and lively with seaweed. These macroalgae not only produce oxygen for marine species through photosynthesis but also serve as the base of the marine food chain. Scientists predict this seaweed colonization could lead to a higher rate of carbon sequestration and higher productivity in marine system, but the local biodiversity might be reduced. Glacial retreat has a major influence on coastal ecosystems – it creates ice-free areas which can then be taken over by marine species. However, the process is not always that simple. A recent study published in Polar Biology by D. Deregibus et al. discovered that although newly exposed ice-free areas favor colonization, sediments carried by glacial runoff makes seawater less clear and affects coastal marine species adversely by reducing the survival or reproductive rate. Nonetheless, seaweed in Potter Cove has adapted to shade and can tolerate darkness for a long period as it is accustomed to ice cover blocking sunlight. Increased turbidity, or cloudiness, caused by sediments affects the distribution rather than survival of Antarctic seaweed, Deregibus and his colleagues found. The study investigated how the availability of incoming sunlight affects seaweed distribution in newly ice-free areas in Potter Cove, South Shetland Islands in Antarctica. Researchers found that the more sunlight breaks the surface of the water, the more seaweed can thrive. Levels of sunlight are influenced by the amount of sediments that runoff glaciers as they melt as sediments can decrease water clarity and light penetration. In Potter Cove, high loads of sediment are produced during the summer melting season. This phenomenon is more evident in newly ice-free areas closer to glacial runoff. Both seasonal and spatial variations in water clarity affect the depth distribution of macroalgae. The vertical distribution in areas close to glacier runoff is reduced due to higher concentration of sediments, researchers found. In this study, three major factors – turbidity, salinity and temperature – were examined to assess their influence on seaweed’s vertical distribution. The results indicate that changes in salinity and temperature do not significantly affect photosynthetic performance of seaweed; instead, turbidity is the main controlling factor. Specifically, how deep the light can penetrate determines the maximal depth distribution limit of seaweed. The depth at which seaweed can survive is controlled by the amount of available light. In addition, carbon balance also affects what kinds of seaweed can be found at different depths. The mystery of how these two seaweeds survive even when there is little light lies in carbon balance. During spring, when more sunlight reaches deep water, the seaweed starts accumulating extra carbon storage compounds. These accumulated carbon compounds can then be used to sustain their metabolism in summer, when inflowing sediments block the sun. The rapid increase in temperature has caused significant glacial retreat as well as sea ice decrease in the Western Antarctic Peninsula. This glacial retreat has lead to an increase in the rate of sediment deposition. Such inflow of sediment into the marine system will affect the coastal ecosystems, especially distribution of species, according to researchers. As temperatures continue to rise in the future, the spatial distribution of seaweed is expected to expand further in new coastal areas. However, how exactly such expansion will affect the coastal ecosystem remains a question for future study.   Spread the...

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Photo Friday: Glacier Illuminated by Aurora

Posted by on May 22, 2015 in All Posts, Art/Culture, Featured Posts, Images | 0 comments

Photo Friday: Glacier Illuminated by Aurora

Spread the News:ShareThis week’s photos feature the Athabasca Glacier in Alberta, Canada with Northern Lights in the background. Photographer Paul Zizka captured ice climber Stuart and Takeshi Tani hanging from the glacier when the Northern Light hits the sky. Paul Zizka is a professional mountain landscape and adventure photographer based in Banff, Alberta. He has a passion for shooting alpine sports and capturing the unique features of nature. “My hope is that through my photography, people will rediscover the precious connection they can have with the wonders of our planet,” he said. For more photos from Paul Zizka, please look here. aurora3 aurora4 aurora5 aurora6 aurora2 aurora1 Photo Friday highlights photo essays and collections from areas with glaciers. If you have photos you’d like to share, let us know in the comments, by Twitter @glacierhub or email us at glacierhub@gmail.com.  Spread the...

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Glacier Retreat Threatens Insect with Extinction

Posted by on May 5, 2015 in All Posts, Featured Posts, News, Science | 0 comments

Glacier Retreat Threatens Insect with Extinction

Spread the News:ShareAs glaciers retreat, a species of glacier-dependent stonefly faces extinction. In 2010, the Center for Biological Diversity petitioned for Zapada glacier, a western glacier stonefly only found in alpine streams of Glacier National Park, Montana, to be listed as endangered species under the U.S. Endangered Species Act. This species – one of more than 3500 species of stonefly –  is highly restricted to cold, glacial meltwater with limited dispersal ability. Now, in an effort to save this endangered stonefly, the Center for Biological Diversity filed a lawsuit against the U.S. Fish and Wildlife Service to address the urgency of protecting this stonefly. The insect could potentially be taken to other clean cold streams outside its established range, perhaps further north or at higher elevation where it might survive – but time is running out. Species evolve to survive in specific temperature ranges; however, when the environmental conditions have exceeded the range, species are unable to adapt to new conditions immediately. Climate change has put many species in danger, but this is the first time that an insect species has been threatened with extinction by glacier retreat. “Protection can’t come soon enough for this stonefly,” said Tierra Curry, a senior scientist at the Center for Biological Diversity. “Glacier National Park will have no glaciers in 15 years if we don’t take action to curb climate change.” Stoneflies are a particularly ancient order of insects that spend most of their lives in water. They are considered the most sensitive indicators of water quality in streams as they require fresh, clean water and don’t tolerate pollution. The insects have a one to two-year life cycle starting in the nymph stage in fresh meltwater. They usually emerge from the water in late spring when the stream is uncovered by melting snow. Z. glacier has a narrow temperature preference around 3.3 degrees Celsius. It is this narrow temperature preference that makes this insect especially susceptible to climate change. Between 1960 to 2012, the average summer temperature in Glacier National Park has risen by approximately 1 degree Celsius. Additionally, since 1850, 125 of the 150 glaciers in Glacier National Park have melted away while the remaining 25 are predicted to disappear by 2030. The loss of glaciers as well as restricted suitable environmental conditions and limited dispersal ability of the stonefly threaten the species’ ability to survive. Few studies have investigated the impacts of climate change on alpine species distributions. To compensate for this knowledge gap, J. Joseph Giersch from US Geological Survey and other researchers looked at the current status and distribution of Z. glacier. Their results were published in Freshwater Science. Giersch et al. sampled 6 alpine streams, where Z. glacier was historically known to live, to examine the relationship between species occurrence and environmental variations of temperature and glacial extent. In order to identify the current geographic distribution and distinguish Z. glacier from the other 6 Zapada species in Glacier National Park, the researchers used morphological characteristics, the outward appearance of adults and the DNA of nymphs. Giersch et al. identified 28 suitable alpine locations in Glacier National Park as potential habitats for Z. glacier. From this study, Z. glacier was only found in 1 of the 6 historically occupied streams – the outlet of Upper Grinnell Lake. The results suggest increased temperature and glacier retreat have already caused local extinction of Z. glacier from several historical locations. The stonefly was also detected in 2 new high-elevation locations in Glacier National Park. Therefore, only 3 out of the 28 potential habitats have Z. glacier. The results indicate that the historical distribution of...

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