Posts Tagged "patagonia"

What Do Black Southern Cod Like to Eat?

Posted by on Aug 4, 2015 in Featured Posts, Science | 0 comments

What Do Black Southern Cod Like to Eat?

Spread the News:ShareIn the freezing waters of Patagonia, southern Chile, the black southern codfish takes what it can get. With different levels of salinity and nutrients at the mouths of fjords and channels, the black southern codfish maintains regional feeding habits, a new study has found. Researchers Matthias Hüne and Rodrigo Vega, from the Institute of Ecology and Biodiversity (IEB) and Fisheries Development Institute in Chile, collected fish samples in gill nets to observe and evaluate how the feeding pattern variation of black southern cod is influenced by oceanic and continental water in the Staples Strait in Captain Arancena Island and Puerto Bories in the Ultima Esperanza fjord. Since the black southern cod, an ice fish, is extremely abundant in Patagonia, Hüne and Vega wanted to better understand the trophic structure of the species, which will contribute a more complex understanding of the trophic ecology of fish in Chile. In the coming years, glacier melt is likely to reduce the salinity in surrounding oceans in these regions off southern South America. As a result, the diversity of prey species for the black southern cod will most likely be promoted, meaning that the oceanic food webs may become more complex. It is plausible that those fish will not be intensively affected by changing climate because they are highly adaptable to both higher temperature and lower salinity environments. By dissecting fish samples, the authors of the study were able to determine the diet composition of the species in selected regions. The authors investigated the spatial differentiation in diet composition of black southern cod by taking into consideration both environmental factors (salinity, temperature, oxygen concentration) and biological factors (gender, size). Through this study, they were able to develop a series of factors that predicts the spatial variation for the diet of the fish. Ultimately, Hüne and Vega ascertained that in Staples Strait, the black southern codfish primarily preys on polychaetes, multi-segmented worms that have fleshy bristles protruding from each segment and which are present from abyssal depth to rocky shores.In Puerto Bories, however, the black southern codfish preys mainly on algae and on crustaceans, including ostracods (“seed shrimp” with two shells that exist in almost all aquatic environments, including hot springs) and gammarids (shrimplike creatures which can swim upside-down, backwards or on their sides). Even though there is hardly any difference in the diet pattern among different sexes of the fish, small-sized black southern cod were found to have relatively lower proportion of empty stomachs. There is no doubt that environmental variables play a vital role in affecting the feeding variability of the black southern cod. Theoretically, the fish is prone to consume more diverse prey items where there is higher temperature and lower salinity, which accounts for the relatively high prey diversity in Puerto Bories. The adequacy of potential prey species could largely be attributed to suitable environmental conditions. According to Clarke and Johnston, the metabolic rate of fish in warm water is anticipated to be comparably higher, which could be an explanation for the phenomenon. Furthermore, the research found that small-sized black southern cod mainly prey near the surface of the ocean (or in benthic zone), where the majority of their food comes from ostracods and gammarids. Nevertheless, large-sized species spend most of their time in preying on polychaetes in the water column. Hence, there is no surprise that most of the black southern cod from Puerto Bories were smaller than specimens from Staples Strait. In conclusion, the black southern cod from different locations exhibits various feeding patterns, in which temperature and salinity of the ocean, as well as their physical condition, play an important role in shaping diet....

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Roundup: Fish in Patagonia, Film in Kashmir & Glacial Georgia

Posted by on Jun 29, 2015 in All Posts, Art/Culture, Featured Posts, News, Science, Uncategorized | 0 comments

Roundup: Fish in Patagonia, Film in Kashmir & Glacial Georgia

Spread the News:ShareOne Fish, Two Fish: Black Southern Cod maintain a more diverse diet when near glacier meltwater areas “The black southern cod, Patagonotothen tessellata, is the most important notothenioid fish species in terms of abundance in southern Chilean Patagonia. However, studies on its trophic ecology are scarce. [This study assessed] the spatial variation in the diet of P. tessellata between two localities, one with oceanic influence (Staples Strait) and another with continental influence (Puerto Bories)… The black southern cod presents spatial differences in diet composition among contrasting environmental localities… The results provide evidence of two dietary patterns depending on the type of environment in which they are distributed, highlighting the potential role of the environmental variables on the availability and abundance of potential prey and in structuring diet.” More here. Glaciers in the Spotlight: Salman Khan films dramatic scene at Thajwas glacier, Kashmir “No doubt Salman Khan’s films are incredible exciting and dramatic, but his forthcoming release ‘Bajrangi Bhaijaan’ has even gotten better… ‘The Bajrangi Bhaijaan climax was shot at the base of the Thajwas glacier outside Sonamarg. Located at 10,000 feet above sea level… the 300 strong technical crew had to trek for an hour through snow every morning to reach the location. Added to this was were the 7000 extras that we had on set every day. Transporting them in hundreds of buses and then embarking on the hour-long trek was a huge logistical challenge for the production. To add to their woes was the sub zero temperatures and hail storms that would interrupt the shoot,’ said Kabir Khan who has previously worked with Salman in ‘Ek Tha Tiger.’” Read more here.   Glacial Melt in Georgia, Communities Threatened by Avalanche “Considering its size, Georgia has a large number of glaciers. In the mountains of Georgia, there are about 786 registered glaciers, with a total area of about 550 km. About 82.5 % are in the upper courses of the Kodori, Inguri, Rioni, and Tereck rivers. For the past 150 years, significant glacier retreat (0.8–1.7 km) and shrinking of their area by 16 % has been observed. Since the middle of the 1940s, the glaciological situation has been characterized by a sharp reduction in the glacial area, but with the simultaneous increase in their number as glaciers disintegrated into separate smaller ones, although at the same time separate movements have also taken place. Avalanches are common in Georgia. Nearly 340 inhabited places are under the threat of avalanche attacks. About 31 % of the territory of Georgia is subject to avalanches (18 % in eastern and 13 % in western Georgia).” More here. Spread the...

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Roundup: New Museums, Ice Quakes, and Ice Caves

Posted by on Mar 16, 2015 in All Posts, Art/Culture, Featured Posts, Roundup | 0 comments

Roundup: New Museums, Ice Quakes, and Ice Caves

Spread the News:ShareGlaciarium – A New Museum Dedicated to Patagonian Glaciers Opens in Argentina “Designed as an environment that promotes knowledge and awakens the senses, Glaciarium seeks to emotionally move the visitor through noble visual and narrative resources . . .” Read More, here.   Calving Glaciers causing “Ice Quakes” Analysts at the Alaska Earthquake Center discovered that calving glaciers cam cause seismic readings of earthquakes. Read more, here.   New International Workshop on Ice Caves published by the National Cave and Karst Research Institute “International experts discuss ongoing research efforts and promote global cooperation in ice cave science and management. The 97-page proceedings of the 6th IWIC contain 20 high quality papers and abstracts that cover ice caves and glacier caves eight countries, three continents, and some extraterrestrial bodies. Topics include modeling, measuring, and monitoring of ice and glacier cave processes, microclimates, and cave ice, as well as the effects of climate change.” Read the report here.   Spread the...

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Glaciers Influence Marine Invertebrates in Chile

Posted by on Feb 25, 2015 in All Posts, Featured Posts, Science, Uncategorized | 0 comments

Glaciers Influence Marine Invertebrates in Chile

Spread the News:ShareZooplankton are tiny creatures that drift in water bodies. A recent study by Meerhoff et al. in Progress in Oceanography describes linkages which connect them with glaciers. The researchers observed meroplankton—organisms which have planktonic features in their larval stages, but live sessile in the bottom as adults. They worked in the fjords of the Baker River, which is located between the Northern and Southern Patagonian ice fields in Chile. Physical and chemical conditions vary widely in these fjords, due to tides and to seasonal fluctuations in glacier meltwater and other contributions to river flow. These varying conditions, in turn, influence the dynamics of zooplankton communities, including productivity patterns, biomass, and community structure (the distribution and interactions of different species). Zooplankton community dynamics in fjords are influenced by the strong vertical and horizontal gradients in hydrographic structure, such as freshwater discharge and tides. Studies have shown that temporal and spatial distributions of zooplankton are controlled by environmental conditions. Temperatures influence temporal scale by influencing metabolic rates and swimming behaviors of zooplankton. The salinity of water constrains the spatial distribution of estuarine zooplankton because each species can tolerate only certain levels of salinity. These two environmental factors also influence food availability and predation stress, which also affects the community structure of zooplankton. The input of freshwater from glacial meltwater can change salinity, generate internal tides and reshape the circulation pattern in estuarine systems. Moreover, the turbidity of the water is influenced by glacial input. Even though the glaciers are virtually pristine, the meltwater is able to carry sediments along its way, known as rock flour. These finely ground particles, formed by the interaction of glaciers with their beds, are so small that they remain in suspension, making the water less transparent. This increase in turbidity limits light penetration and thus restricts primary production through photosynthesis by phytoplankton—the minute plants which float in the water column. Using vertical tows, Meerhoff and her associates collected samples in three sites close to the river mouth, during the Baker river minimum outflow season (October 2012) and during the maximum outflow season (February 2013). They observed strong hydrographic gradients, both horizontal and vertical, in early spring (October) and late summer (February). They have also found that these two seasons are significantly distinct in water-column conditions. Such variations are largely caused by freshwater discharges from nearby glaciers. This study found a number of kinds of meroplankton in these fjords; the dominant organisms are larval forms of barnacles, squat lobsters, crabs, snails and bivalves. The study also indicated that zooplankton community shows seasonal variations. Specifically, barnacle larvae are favored in spring, when river outflow is at its minimum, while its food sources, phytoplankton, are more abundant. In contrast, bivalve larvae are dominant in summer due to higher surface water temperature. At this time, river outflow is at its maximum and phytoplankton availability is much lower than in spring, reflecting the greater turbidity of the water that carries glacier rock flour. Studies are needed to demonstrate whether bivalve larvae in this estuary feed on bacteria when phytoplankton are unavailable, as they do in other regions. This study shows how freshwater input, along with other factors, affects zooplankton composition and distribution. It is remarkable to think of the numerous marine invertebrate larvae whose populations respond to glaciers located well inland of their estuarine home. Look here for other stories about invertebrate life near and on glaciers. Spread the...

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Photo Friday: The Frozen Diamonds in Patagonia

Posted by on Oct 10, 2014 in All Posts, Art/Culture, Featured Posts, Images, News | 1 comment

Photo Friday: The Frozen Diamonds in Patagonia

Spread the News:ShareA Glaciers Photo Contest was held last summer by ViewBug and Resource Magazine. It is difficult to capture galciers due to the size, location, and reflection of light. However, the winner of this contest, Paul Cashman, mastered the task with “The Coldest Shots of Patagonia“. In order to well capture these cold giants, he traveled to Torres Del Paine and Mount Fitzroy in Chile and Argentina where most of the pictures were taken. Check out the wining photo of Paul Cashman and more photos for this project, or visit his website. 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. Perito Moreno Glacier The Coldest Shots of Patagonia (source: © Paul Cashman) Perito Moreno Glacier Glaciers Photo Contest Winning Photo (source: © Paul Cashman) Perito Moreno Glacier The Coldest Shots of Patagonia (source: © Paul Cashman) Perito Moreno Glacier The Coldest Shots of Patagonia (source: © Paul Cashman) Perito Moreno Glacier The Coldest Shots of Patagonia (source: © Paul Cashman) Perito Moreno Glacier The Coldest Shots of Patagonia (source: © Paul Cashman) Perito Moreno Glacier The Coldest Shots of Patagonia (source: © Paul Cashman) Perito Moreno Glacier The Coldest Shots of Patagonia (source: © Paul Cashman) Spread the...

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