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Hello all,
I am attempting to express a Plasmodium gene which is extremely AT rich with several repetitions of the same. The peptide I am attempting to express is 506 amino acids long.It has 2 distinct overlapping domains(which i am trying to express together). However I have tried Ecoli BL21(24*C for 12hrs) and Arctic strains(12*C for 24hrs) but I have not been able to generate it. It has a C terminal 6x his tag and not being picked up by western blot. I am using pet24b vector.
I am new at these procedures and any help or suggestion from the community to shed light into this would be of immense help!
Thank you
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Codon frequency optimization for the target host is crucial in my experience. It can make the difference between no yield at all and decent expression, esp. when the phylogenetic distance is huge, as it is in your case, between a plant and a bacterium.
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Respected all ,
I have been attempting to purify this protein (mol wt - ~17kda). The protein is being expressed in Arctic(DE3) E.coli cell. However I am having an annoying problem of impurities/contaminants, which I am being unable to remove. I am using TritonX100 in the lysis buffer(300mM NaCl, lysozyme, PMSF, 0.25mM arginine) to solubilize the protein. I perform IMAC and I use 100uL of Ni-NTA beads (which I wash with 50mM tris and 500mM NaCl) in the batch method, wherein I am incubating 30ml of the lysate at 4*C for 16hrs.
However the problem is there is a lot of other protein which come up in the elutes along with my protein of interest. Even in the post incubation wash (without imidazole). The sds-profile of flow through , beads and elute are pretty similar as if purification is not happening!
Any suggestion to purify my 6x-His tagged protein would greatly help ! I am using pet24b plasmid
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I agree with the other comments that it is better that you use a packed bed where you have control of flow. For example BabyBio Ni-NTA 1 mL (www.bioworks.com) which you can easily use with a pump on the bench or a syringe if you don't have a chromatography system. Always add some imidazole in your sample and washing buffer to prevent unspecific binding to the Ni-charged resin. With higher concentration of imidazole less impurities will bind, but if you add too high concentration of imidazole your His-tagged protein will not bind either so this has to be optimized for each protein.
Another option is to instead of Ni-charged resin you can try a cobolt charged resin. These resins usually bind less tight so you bind less impurities , but also your target protein may bind less tight so the yield may go down a bit, but the purity often increase, you can test BabyBio Co-NTA 1 mL prepacked columns.
I have attached some information material to give you some tips, for example the BabyBio Screening kits for purification of His-tagged proteins to find the optimal metal ions to use as it is so easy to think that Ni-charged resins always are the best ones.
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Melting of ice covering the Arctic Ocean would increase evaporation and precipitation. Snow precipitation in the continent surrounding the Arctic Ocean would lead to origin of new glaciers triggering a new ice age.
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The decision whether the climate is going colder or warmer rests with the gases in the atmosphere. It has been like that since the creation of the Earth.
If you increase the greenhouse gases (the case today) the climate is going to be warmer. The more these gases, the warmer it gets.
If you decrease these same gases a lot, you get an Ice Age.
Once in a while the balance of gases is upset by a collision with an asteroid, but that is very rare.
At the moment the greenhouse gases are extremely high and getting higher as people refuse to abandon the burning of the fossil fuels.
If you are able to remove these greenhouse gases from the air (anything is possible) a new Ice Age can be achieved.
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Since 2001, warming increasing repeatedly as global average temperatures in 2015 were 1 degree Celsius or more above the 1880-1899. The rapid declining of Arctic sea ice both the extent and thickness, over the last several decades and retreating of glaciers i.e. the Alps, Himalayas, Andes, Rockies, Alaska and Africa around the world. Does pollutant or increasing GHG is the main reason for changing in temperature globally?
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Our university project group is studying the possibility to apply a plan for the (local) restoration of ice based habitats of polar bears (Ursus maritimus). Has the idea already been developed in some way?
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Does anyone know where I could find data of cloud cover at fine temporal resolution (hourly, 4h) in the Arctic?
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Thank you, Guillermo, for your answer. It seems I can not find daily (hourly) data, but only seasonal average. I am missing something?
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Hi, I'd like to try expression of reverse transcriptase with low temperature, 15 °C, due to solubility. Should I use some special plasmids for cold expression? I ordered cells for this purpose - E.coli Arctic express. Is it enough or is it better to combine these cells with plasmids for cold expression? Thank you all!
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you can try the pcold vecotrs of takara
i used in some year ago for a protein fusion that was degraded with expression at 20-25-30°C in pet vectors and performing the expression at 17°C, I obtained good results.
you can see an example of it at minute 6' 10'' of the following video
present in my blog: ProteoCool
Sincerely in other cases, with more stable proteins they provided lower expression than vectors based on T7 promoter therefore i suggest to you to test it in parallel with T7 and not replace it.
good luck
Manuele
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Before wanting to reduce emissions of greenhouse gas in particular, it is necessary to know the sources and the dynamics. This is what NASA researchers hope to do with a new 3D model that sheds light on the movements of methane in our atmosphere.
Methane (CH4). According to experts, this gas is responsible for 20 to 30% of the temperature increase recorded to date in the context of global warming. And researchers from NASA (United States) are today presenting a new 3D tool intended to visualize the diversity of sources of this powerful greenhouse gas and to track its concentrations and its movements in the atmosphere.
Remember that the global warming potential (GWP) of methane is 25 times greater than that of CO2. And that the sources are numerous. Methane is emitted when fossil fuels such as coal, oil or gas are used. But the oceans also emit methane. Just like wetland soils or agriculture. Rice cultivation, in particular, as well as animal husbandry. Overall, "it is estimated that up to 60% of the current methane flow from the earth to the atmosphere is the result of human activities," said Abhishek Chatterjee, researcher, in a NASA statement. But it remained difficult for scientists - due to a lack of measurement and understanding of feedback phenomena - to predict future trends.
To solve this problem, NASA researchers collected data from emission inventories, field campaigns and even satellite observations. Data they have injected into a model that also estimates emissions from known natural processes. And which also simulates atmospheric chemistry which breaks down methane. Then they added a meteorological model to visualize the path of methane in our atmosphere.
A wide variety of methane sources
The proposed 3D visualization highlights the complexity of the question. It illuminates the movements of methane in the atmosphere according to the landscapes and the seasons. It also shows that high altitude winds can transport methane very far from its sources. It also highlights some specific regions in this area.
Thus 60% of methane emissions come from the tropics. Particularly because the Amazon basin and its wetlands seasonally create, when flooded, an environment low in oxygen and therefore favorable for emissions.
Europe, on the other hand, seems rather preserved. It is the only region that has experienced a decrease in emissions over the past 20 years.
In India, rice and livestock are the main sources of methane emissions. And it is mainly the management of livestock and agricultural waste that currently results in the region, an increase in emissions of 1.5% per year. More generally, in Asia, more than 85% of methane emissions are due to human activities.
Conversely, in the Arctic, more than 70% of emissions are of natural origin. But high latitudes still appear to be responsible for 20% of total emissions. And researchers are concerned about the greenhouse gases that warming soils could release into the atmosphere.
WHAT YOU MUST REMEMBER
Methane is a powerful greenhouse gas.
NASA today offers researchers a new tool for studying the behavior of this gas in our atmosphere.
It already reveals some great patterns.
Regards
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The more important source of methane at depth (crystalline bedrock) is abiotic. Abiotic means that methane is created from inorganic compounds, without biological activity, either through magmatic processes or via water-rock reactions that occur at low temperatures and pressures, like serpentinization.
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For example, I know that FWI has been adapted for Mediterranean forests (DOI: 10.1007/s11069-014-1397-8). Do you know similar studies for Arctic regions?
Thank you
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Hi Enrica,
I think this is an interesting topic to conduct research on. Below, I have listed five articles for your reference that I think described the scenarios well. The last reference excluded parts of the Canadian and Russian high Arctic.
All the best,
Ebrahim
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Last Tuesday (8), exactly on World Oceans Day, the US National Geographic Society cartographers decided to present planet Earth with another ocean by adding the Southern Ocean, which surrounds Antarctica, to its four "brothers" older Atlantic, Pacific, Indian and Arctic.
According to Seth Sykora-Bodie, a marine scientist at the US National Oceanic and Atmospheric Administration (NOAA), while it's hard to explain what's different about the region, “everyone will agree that the glaciers are bluer, the air cooler, the mountains more intimidating and the landscapes more captivating than anywhere else you can go,” he told National Geographic.om another ocean by adding the Southern Ocean, which encircles Antarctica, to its four older “brothers” Atlantic, Pacific , Indian and Arctic.
NOAA's official geographer Alex Tait also spoke to the NatGeo website, explaining that official recognition just didn't happen before because “there was never an international agreement”. “It's kind of a geographic geek in some ways,” he summed up. But as of June 8, 2021, the nerd is over: the Southern Ocean is officially the fifth ocean on Earth.
Although the difference between sea and ocean is clear, the size, it is still difficult to say exactly what an ocean is, other than to repeat that they are more extensive liquid masses (the smallest of them is 73 million square kilometers) and deeper. The Spanish navigator Vasco Nuñez de Balboa already recognized, in the beginning of the 16th century, that those waters at the bottom of the world were the "Antarctic Ocean".
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Good question! but it is out of my field.
we follow to learn from experts. Good luck!
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Delivery of containerized cargo to an unequipped coast in the Arctic
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Geared containerships are needed.
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Hello!
Looking for informative maps of ice compression and vessel besetting in the Arctic area – to use in the presentation. Is anyone aware of such maps – for the whole Arctic Area or local areas?
Thanks in advance for possible advices and discussion.
Regards,
Igor Buzin
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Hello!
Thank you for the good link for interesting presentation. The zones of the ice cover converging are of most interest, of course. Suppose some maps do exist with such zones depicted of a global and local scales. Years ago I've seen such maps drawn by hand, but I hope some more new and actual material could be found. Anyway, many thanks for the hint.
regards,
Igor Buzin
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I'm recently doing the research on the impacts of smouldering in the arctic, but due to the travel restriction, I'm doing this remotely. My current issue is to identify the smouldering from satellite data, distinguish it from general wildfires. Does anyone know any method which can allow me doing this?
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10.1109/ACCESS.2021.3053605
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I know, the question is a bit simplistic. It is also not only about the plants, but more about the photosynthetic organisms ... However, in this time of global biodiversity crisis, we are constantly confronted with prioritizing. Recently I read somewhere that in the Arctic, the photosynthetic algae should be taken care of and not the polar bears. Also in temperate regions, where the habitats are under enormous pressure, shouldn't we pay the greatest attention to the producers/plants? On the local level (local administration, journalists) I am constantly confronted with the question: who do we save first? With this somewhat provocative question, I simply wanted to know/hear what researchers from various fields will say about it (or against it).
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No, all life is essential.
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I am doing research paper Russian geopolitical interest at Northern sea route. .Soviet and Arctic had long history from 1930, exploring naval base by Arctic circle as today research develop nuclear icebreaker development experiment of raw materials, fisheries, oil etc. EurAsia trade with China and other as one of reason Russian economy is rebuilding,, but in long run Russian could benefit from climate change. I want discuss different opinion, fact and point some problem it could face problem with other global players.
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The Northern Sea Route (NSR), a growing shipping lane linking South-East Asia with Northern Europe through Arctic waters, is set to become a competitor to the Suez Channel for cargo delivery between these two regions.Since the mid-1930s the Northern Sea Route has been an officially managed and administered shipping route along the northern/Arctic coast of Russia.According to the New York Times, this forebodes more shipping through the Arctic, as the sea ice melts and makes shipping easier. Check the following journal about Russian policy, interest for the northern sea route.
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Hello everybody!
Looking for a good source of information on strong and extreme winds in the Arctic (monthly values, annual extremes etc.). The form of maps (with isolines) will be most interesting (atlases? papers? reports?). Your kind advises will be highly appreciated, thanks in advance.
With the best regards,
Igor Buzin
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Many thanks for answering.
Will be looking for some new papers and estimations.
regards,
Igor Buzin
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Hello!
This a special question to the naval architects / shipbuilders.
Looking for some tentative estimations of the possible increase of the cost of the vessel built in accordance to be able to operate in the Arctic/Sub-Arctic in comparison to the vessel of the same dimensions/purpose intended for use in the moderate conditions and having no “winterization package”. What could be the cost differences between these two vessels?
I’ve heard about “+30% of cost”, need clarification of this estimation.
Thanks in advance for possible discussion and your opinions.
Best regards,
Igor Buzin
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Well, the difference still exists.
I'd like to know the approximate values (from the economical point of view), not digging too deep in the future cliate change.
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I am starting a project to compare different meteorological sensors for austere sites (no power, and little solar or wind availability). I know battery performance is a topic I will have to cover, and at this point I have sensors running on NiCd, Li-Ion, and lead-sulphate battery technology. So far most sources focus on only one battery type usually applied to hybrid or normal cars. The internet has some information, but looking for a/some citable articles.
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There are two relative papers that would be helpful as below:
1-A Critical Review of Thermal Issues in Lithium-Ion Batteries
Todd M. Bandhauer3,1, Srinivas Garimella5,1 and Thomas F. Fuller4,2
Published 25 January 2011 • © 2011 ECS - The Electrochemical Society Journal of the Electrochemical Society, Volume 158, Number 3Citation Todd M. Bandhauer et al 2011 J. Electrochem. Soc. 158 R1
2- Thermal issues about Li-ion batteries and recent progress in battery thermal management systems: A review
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  1. During the daytime, shortwave net radiation is greater than 0 due to albedo is less than 1. If all-wave net radiation shows negtive value for Arctic, Greenland, and Antarctic area, it indicates surface energy is being lost throughout the daytime and night. Is this correct? If so, how to explain it?
  2. Anyone konw this issue, thanks a lot for your reply.
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Dear Jiang,
I am also facing the same issue with data. How you sort out?
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While working in the Subarctic of Western Siberia, we noticed that in places of active thermokarst the biological productivity of vegetation increases. Plants that are absent in nearby ecosystems with stable permafrost grow in thermokarst-affected ecosystems. Thermokarst is usually associated with human influence. What are the typical responses of productivity and biodiversity to the effects of thermokarst in your research area? Why does thermokarst increase vegetation productivity? Is this a thermal effect? Is this the effect of increasing soil fertility? Is this the effect of reducing competition from indigenous zonal flora? Or is it a complex of the listed reasons?
I am attaching a photograph of the community on the thermokarst slope and a photograph of a typical tundra (latitude N70 °).
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A vessel has cracks and pitting in bridge windows. The vessel operatures in extreme climates, hot and cold, from arctic to Equatorial. Looking for failure predictions.
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There is no link to the article.
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I am currently working on my PhD, and need some background information on the shore-line chronologies related to archaeological cultures and sites in the northern Fennoscandia. I would like to ask the community, if any could give some good references on the subject: a) basic works on the shore-line chronologies and archaeology, and b) new research on the same issues in the coast of Norwegian Arctic Ocean (and Varanger Fiord) and in the coastal Kola Peninsula, Barents Sea and also the White Sea.
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Yes, Kolpakov for sure, but I would ask also Aleksandr Zhulnikov (Petrozavodsk) and maybe Dmitriy Gerasimov (Kunstkamera). Write me if you need emails.
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We are replacing an old CN analyzer in our communal lab and are reaching out for any recommendations on equipment. Ease of use, purchase and maintenance cost, and reliability are our main criteria. The soils will range from mineral agricultural soils to organic soils from the Arctic. Thanks!
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Believe it or not Eltra... The new generation of analyzer is wonderful. Best price, great support from service and applications.
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Any data science and/or remote sensing experts have any insight pertaining to multivariate regression and deep neural networking with large feature set inputs and variable temporal data holes necessary for my dissertation work regarding climate change in the Arctic? I would greatly appreciate the feedback!
As an aside, I have utilized feature and stepwise extraction, most NaN mitigation methodologies, and VIF to mitigate multicollinearity prior to training. I’m simply seeking a deep learning solution that integrates all possible data to generate the best model.
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Hello. You are working in an important area. It is my pleasure to suggest something.
I'm sure you're aware that the main benefit of deep learning approaches (compared with conventional machine learning) is that they do not require prior feature definition. On the other hand, they do require significant computational resources (GPU, lots of RAM, etc) and typically take only images as input. Thus, when you say you have a multivariate regression problem with temporal data gaps, you will first of all have to look at how the data can be "rasterized" into an image format. It is OK to use either grayscale or colour images, and most deep learning architectures can take at least a few sequential images as input - the easiest case being 3 successive images loaded onto the RGB channels of a colour image.
If you really want to try sequential techniques you need to look at RNN architectutes also, which typically take vector inputs but are designed to fit a sequence of data vectors. The GRU and LSTM approaches are the most successful ones since they allow for long process memory while avoiding numerical problems due to "vanishing gradients."
Another approach is GANs (generative adversarial networks), which are very good at learning multi-dimensional probability distributions for image data. In this type of approach, which has typically been used to fill gaps in images (inpainting), the deep neural network is trained to generate realistic images that a discriminator network cannot distinguish from the real data. Depending on the dimensionality of your data, you might be able to massage your problem into a format for which a GAN can be applied.
A simple initial approach might be to use segments of your data that do not have holes and develop a sequential predictor for this data. Then apply your predictor to the segments with holes to see how well you can bridge the gap.
Is there a "best" method? No. All deep learning and AI work is heuristic for now. There are not really any accepted design rules, although there are various benchmark data sets for image recognition. Performance metrics should be defined that are appropriate for your problem and keep your test data separate from your training/validation data. Data augmentation is usually helpful unless you have a lot of data and don't need to augment.
Please recommend if you find this answer useful.
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Chemical analysis of layers of ice (arctic, antarctic) revealed evidence of climatic changes occurring long before human started polluting our planet-
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interesting question
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Dear Scholar
No. It is not impossible with the REAL & EXACT Pi Value.
The present 2000 year old polygon based so called pi number ; 3.1415926....is NOT PI NUMBER. ( for example all birds can not cross ocean although they appear same . Only one bird Arctic Tern can cross a ocean So, Real Pi is an Arctic Tern ).
Further real Pi is an ALGEBRAIC Number.
Hence, we can get the square root of Pi.
Pi is a geometrical constant. Its official value is 3.14159265358… March 1998 discovery says Pi value is 3.14644660941…. With the official number square root of Pi and squaring of circle are impossible. With 3.14644660941… root Pi is possible and squaring a circle is also possible and done in this paper.
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Wow.. 2000 years and all the mankind was wrong about Pi number.
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Hello All,
We collected samples from the Arctic and need to get an idea about the best culture media that could be used to purify and culture the green algal components.
For cyanobacteria, we regularly use the BG11 medium but it will be great to have some advice for green algae.
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please read this article. Effect of Culture Medium on Growth of Blue Green Algae https://www.ijcmas.com/7-10-2018/K.T.%20Thakare,%20et%20al.pdf .
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Does anyone know where such data could be available?
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Hi
Guillermo Auad
. Thank you for the link. However, I can not find the data associated with the presented figure. Is it me that is not looking correctly?
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Russian discovery of five Arctic islands and the death of the first Icelandic glacier, Okjökull, are two recent observations for the melting ice in Polar Regions of the earth.
I would like to discuss this matter with RG members.
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Thank you Vaibhav Amarsinh for the comment. Still, I did not find a comprehensive comparison. we will see in the future.
Piyal
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For my project looking at the biodiversity of phytoplankton in the Arctic, I have calculated Hill numbers and Average Taxonomic Distinctness on my samples, and they both tell very different stories so I would like to include them both. I am just stuck as to how I can justify using both, and if I can't, how do I choose which one to include? Has anyone else ever had a similar decision to make?
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It's common to report more than one index. Diversity indices aren't like statistics where you have parametric and non-parametric methods, and only one is appropriate based on the data. They are attempts to describe different aspect of diversity, such as richness, evenness, rareness, etc. Ultimately, it's up to the researcher to interpret what the index is saying because it's just a number from a formula that is meaningless without context and a description. The tool needs to fit the question and what you're seeking to find.
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I will appreciate if someone can help me to identify larvae of Polychaetes I found them in zooplankton samples quite frequently. This sample is from Amundsen Sea. Aslo I will be very grateful if someone can share an identification key or taxonomic guides how to identify polar polychaetes. I also have more pics from Arctic and Antarctic region and I need key for both Poles.
Thank you in advance very much,
Larysa
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could it be a Bathypolaria larvae?
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I'm interested as to why the arctic climate is changing faster than anywhere else? Can anyone mention any mechanisms or theories behind this (apart from the albedo effect) or recommend any papers?
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I think, decreasing albedo due to shrinking sea ice might play a role. Also a denser cloud canopy as result of intensified evaporation might reflect infrared radiation back to the ground in winter. Greening of the Arctic also changes albedo. And methane degassing from thawing permafrost could strengthen the greenhouse effect locally.
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How much REE in arctic aerosol and precipitation?
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Hi all,
I'm looking for climate change projection data in raster format. Something like is shown in the IPCC 5th report chapter 12.
In particular I'm interested in the Arctic, temperature, precipitation and permafrost. I've had a look at the IPCC data centre and a couple of other online data portals, but without much joy.
Does anyone have any suggestions?
Cheers,
Matt
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Dear Matthew,
The raster format is pretty uncommon in the meteorological and climate community. They usually use either GRIB (common among meteorological centers) or NetCDF (popular in climate science) for there vast data sets.
Therefore you may have to get the data in NetCDF and convert the data into an appropriate format (wouldn't tiff also work?). Maybe your data analysis tool might even import NetCDF?
Good luck
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Is burst of polar vortex the culprint behind the abnormal cold weather in US and Canada? Is this linked to the last summer heatwave? Is this alternating severe weather between heatwaves and coldwaves likely to continue under climate change?
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The scientists have already explained this new phenomenon which has only started in the last two years, never before in the records.
Air has to go somewhere when there is a difference in atmospheric pressure. This time, hot air from the south is blasted all the way to the north pole, therefore, the air that normally sits around that pole has to move and moves to N. America.
Yesterday was -54 degrees C, but last year we reached - 60.
Under the man-made climate change protocol, if you like, ANYTHING is possible as far as weather goes. As Sir David Attenborough said so many times, we are in for a "bumpy ride" unless people stopped polluting the air, which is unlikely as most people don't understand the weather.
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Hi everyone.
I am looking for remote-sensing product that would give the date (day of year) freezup and breakup for pixels (~5 km resolution) in the Arctic. Before calculating it myself, I would like to know if such product is already available.
Cheers,
Phil
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Thank you
Guillermo Auad
I will have a good look at this article. Thanks again.
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I wonder whether anyone has used aphid traps in the high Arctic, showing that they make short flights and may transmit non-pers viruses? I have found papers on their presence in Arctic, i.d., etc, but not on their movement. Any info gratefully received. Kind regards. Adrian (Gibbs) I'm an ancient virologist trying to guess how PVY got to North America
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Thank you very much Professor Gibbs for your interest and quick respond. Surely I will get in touch with you.
Kind regards.
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the Arctic Council, made up of the eight nations with territory above the arctic circle. issued an 1800 page report on climate changes in circumpolar regions, representing four years of work by more 300 scientist. the report warned that arctic regions are warming.
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Ice in the Arctic region melts rapidly; this observation can be verified even after occasional satellite image inspection. Temperature changes act in conjunction with other processes such as albedo modifying soot and dust deposition. The synopsis of complex interactions involved in the conversion of ice into a rapidly disappearing "black ice" is presented in the following site:
The black ice is shown in the photo attached to this note (Credit: Joe Raedle / Getty Images). It is remarkable that the ice-modifying compound deposition is often associated with episodic atmospheric transport, the process is very intermittent, for example, see the analysis of a single transport event:
Disappearing ice is linked to the destabilization of the Arctic vortex and extreme fluctuations in weather conditions in the northern hemisphere. The interesting question is: to what extent the combustion process leading to soot deposition controls the atmospheric dynamics?
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Hi,
I am looking for a PDF of the paper 'Estimation of wind loads on ships in wind with a strong gradient', proceedings of 14th international conference on offshore mechanics and arctic engineering, by Werner Blendermann, as input for a discussion on the influence on wind field shape in wind tunnel on wind coefficients and their application.
Many thanks in advance,
Thibaut
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Aleksander Kondratenko Thank you for your response, i went through it quickly and it provides partial answer to my questions regarding the Blendermann wind coefficients. I think i will resort to one of the German documents 'Shiffsform und windlast korrelations and regressionanalyse von windkanalmassungen', for more details.
I you ever come across the article, let me know !
Best regards,
Thibaut
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Hello everyone, 
So, I am facing a kind of weird problem here. 
My SWAT model is situated in a nival, Arctic catchment, and significant percent of it's recharge in summer is snowmelt/icemelt. 
When I was building the model, and my only water input was precipitation, the discharge output was completely different than observed values (maybe not completely different... but definetely too small). 
To "fix" this problem, I used "point source" option in ArcSWAT to "imitate/mimic" few main subglacial outflows from the glacier, which are main recharge sources in the ablation season.
After doing that operation, FLOW_OUT looked much better, but now, I have the problem with calibration in SWAT-CUP. 
Almost every parameter I check with the "one-at-a-time" analysis, seems to be not sensitive. 
Charts look like the one attached (this example is for CN2).
Discharge charts looks good, indeed, but still baseflow and peek flows are too low compared to observed, field data. 
I tried using parameters from the article suggested by Dr Karim Abbaspour (https://www.sciencedirect.com/science/article/pii/S0022169415001985) and none of them seems to be sensitive. 
Any advices are higly appreciated. 
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Dear Krzysztof
I agreed with Christoph about using point source in SWAT model. So, choosing point source for your case might not explainable for hydrological system in your watershed.
For sensitivy analysis it is not sensible to use OAT for SWAT calibration. Because parameters are inter-dependent in watershed. So, you need to use global sensitivity analysis.
Best
Jakir
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hello all,
i am trying to clone and express M. tuberculosis protein in E. coli arctic express cell line.
i got expression in soluble fraction(40%) during small scale expression test but continuously i'm getting problem in purification.
my protein of interest is fused with n-terminal his-tag followed by MBP.
i tried ni-nta, batch binding for 6 hrs at 4 degree Celsius and but when i ran 12%sds page, 90% protein eluted in sample flow, elution had most of the other bands.
when i did binding with maltose resin it was the same situation.
again, my 80% protein of interest was going in sample flow.
thereafter i dissolved Sample flow in 8M urea,again did ni-nta still the protein was in sample flow.
why my protein is not binding to resin?
should i go for codon optimization to get protein from commercial firms?
size of protein 43kda
fusion tag- MBP 43kda
n terminal his tag
complete size 86kda
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It seems that your Histag is not accessible for affinity resin. Put it without MBP and/or put it on C termini. In our case the codon optimization helped for better expression and solubilisation of the protein.
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These were caught in June 2017 in the Arctic Fram Strait (74°N, just south of Svalbard) within the upper 50m (DCM).
The complete catch (vertical Bongo 500um) consisted of intensively red C. finmarchicus C5 individuals. I am new to researching copepods, but could not find an explanation of this. Does anyone know something more on it? Further North (a few days later), they were typically coloured again.
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During intensive feeding copepods (including Calanus finnmarchicus) accumulate fat as drops of red colour. Red calanus occurs in feeding season.
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The results of 2016 expedition of N. Shakhova and I. Semiletov group in East Siberian Sea were published in March 2017. From drilled samples they concluded that the subsea permafrost melts up to 15 to 20 cm pro year. They observed the methane emissions with the largest flows in range of more than 1 kg/m2 daily. They estimate that the entire surface with similar emissions occupies already 10 % of East Siberian Sea, that means from 50.000 to 200.000 km2.
If the hotspots include 10 % of the entire ESAS surface, 200.000 km2 and on this surface, at the estimated quantities 1 kg/m2, we calculate annually emissions, we get 70 Gton. This is today 14 times more in one year, as it is (it should be) the entire methane quantity in the atmosphere (5 Gton). At lower surface margin we get approx. 20 Gton.
And if we stay at before 5 years measured real 200 g/m2, this gives on the estimated hotspot surface 5 times smaller annual quantity of emission, 14 Gton. Already this is almost 3 times of the entire "current official" methane quantity in atmosphere (IPCC).
Take into account that methane is in short time, because its atmosphere concentrations are only rising, 150 times stronger as CO2, and that these today's emissions are already doubling the entire Earth's greenhouse effect. The only solution to save the life on this planet, is to prevent these emissions, to capture them, to use THIS METHANE instead all other fossil energy. How much time do we have ??
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Dear sirs and respectful scientists!
Please stop with such conversation. All !! We are not children.
I think that all of us see the extreme importance of solving the environmental problems, but every with his history, work, obligations and devotion knows different sources and information. We must accept and discuss other's arguments and proves and also tell other in a culture way, if something is not in accordance to our documented facts.
Our mission (of the entire humanity) is to keep this planet and not to show one's or other's (self)importance. We must act on the base of well documented and researched facts, but also on the base of less certain information, if it means a large danger for anything. In this case, I think, we must act in first case with enough big time reserve, because consequences will be too frightful, if we will wait for 1000% firm evidences...
In this moment I don't have time to write longer, but later I will make the answer to some set question in this discussion...
But anyway, thanks to all of you for such rich response. It shows the seriousness of the problem.... In the meantime, please read the presentation I appended in my second answer, just to see, from where the problematic numbers about methane emissions come...
Regards, Milan
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I am trying to express and purify a 60kDa, His10-tagged, recombinant protein containing 10 methionine residues, which I think may be causing the productions of multiple N-terminal truncated species during expression. My initial expression was at 37C, which may have resulted in a rapid expression resulting in the multiple truncated species. With that in mind, my plan moving forward was to try to decrease temperature using the same cell line as before, and if that does not help, transforming my plasmid into Arctic cells which contain the Cpn60 chaperone protein.
Any additional suggestions for methods for minimizing truncation during expression would be greatly appreciated.
Thanks!
Zac
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DEar ZAc
but the his tag is at the N term or at C term?
You can certanilly as Sebastian told you add an N-terminal fusion patner (eg. GST, GSt, Trx, GB1, ZZ) and a enzime restriction site (i prefer TEV to thrombin) that will allow to you to digest your protein and remove the tag after puriication. pmal, pgex are some example of commercial vectors that may allow to you to build this construct). pETG vectors (https://www.embl.de/pepcore/pepcore_services/strains_vectors/vectors/gateway_vectors/) are an interesting set of vectors developed from EMBL that may allow to you to test more tag in parallel. As accademinc reseacher I had the opportunity to use it many years ago during my PhD but i'm not sure if is possible to obtain it. However with modern enzime free cloning approach as PIPE metohds is possibile to modify directly your expression vector buy the addiction of a small tag as Trx.
good luck
Manuele
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Arctic Pole : Weather and Climate
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you can assess the change in minimum and maximum temperature. Observation will show you minimum temperature increases than maximum temperature. Try to focus on temperature change
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I'm looking for examples of Community-based economic developement project in the Arctic. I know well the Canadian context but I'm looking for examples in Alaska, Greenland, Russia and in the Nordic Countries.
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The following might get you started:
BurnSilver, S., Magdanz, J., Stotts, R., Berman, M., & Kofinas, G. (2016). Are mixed economies persistent or transitional? Evidence using social networks from Arctic Alaska. American Anthropologist, 118(1), 121-129.
Colt, S., Berry, K., Bayham, J., Meyer, S. R., Fenichel, E. P., Finnoff, D. C., ... & Meiners, D. (2017). The Alaska Village Energy Model. Environmental Resource Economics.
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We are recruiting two M.S. or Ph.D. students to work on Arctic and agricultural ecohydrology, ecosystem ecology, and expert assessment. We would like to reach the largest possible audience and wanted to know what listservs or venues you subscribe to. Thanks!
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I think any job advertisement web protal will be a suitable and good option.
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Yes. Observations show a global-scale decline of snow and ice over many years, especially since 1980 and increasing during the past decade, despite growth in some places and little change in others. Most mountain glaciers are getting smaller. Snow cover is retreating earlier in the spring. Sea ice in the Arctic is shrinking in all seasons, most dramatically in summer. Reductions are reported in permafrost, seasonally frozen ground and river and lake ice. Important coastal regions of the ice sheets on Greenland and West Antarctica, and the glaciers of the Antarctic Peninsula, are thinning and contributing to sea level rise. The total contribution of glacier, ice cap and ice sheet melt to sea level rise is estimated as 1.2 ± 0.4 mm/yr for the period 1993 to 2003.
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Yes. Observations show a global-scale decline of snow and ice over many years, especially since 1980 and increasing during the past decade, despite growth in some places and little change in others
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I have some references for carbon pools/stocks in these soils (eg. Tarnocai, Koven, Hugelius etc), that I guess are based on the area, but for some reason I cant seem to find the actual area itself.. 
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Thanks, I didn't know this paper! I'm not sure if it is exactly what I need (the area mentioned in the abstract seems to be total permafrost-affected area, not specifically turbels/patterned/cryoturbated soils), but I'll have a closer look in the paper itself..
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I was wondering if there were any publications or data available on the different sea ice zones in the eastern Bering sea and the timing of their formation throughout the year. I'm particularly interested in the types of sea ice found within approximately 200 to 300 km from mainland Alaska. Anything on sea ice in the Kuskokwim Bay would be a bonus. Many thanks. Edouard
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Great thanks Guillermo, do you know of any similar studies for the Bering sea Alaska coast?
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We would like to put collar on foxes in the Arctic. T°c can reach -35°c. We need a GPS logger that can resist to those extreme T°c, a drop-off system, and a VHF unit to be able to find the collar again. Foxes are not easily trappable many times. The best, I think would be to have a WiFi tool on the GPS unit that could send the data on an external logger that we could set up on the dens for example, so that most data are safe. Has anyone does that before? If yes what material have you been using?
Thanks for your help
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The WIFI won't be usable there because it drains too much power and need powerful CPU to handle the software stack.
For "GPS wildlife tracking", there's mainly 2 upload solutions: ARGOS satellite (http://www.argos-system.org) or GSM phone then you can remotely get your data. But my guess there's not that much GSM availability in Arctic... And check if ARGOS covers it.
There is some systems that make "semi-upload": you'll need to be in an area near the tracker to upload its data by "short-range" radio (short range can be some km, as always it costs power).
Some trackers need to be retrieved to get their data.
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With the large amount of current research in to the reduction of sea ice in the Artic, has anyone written any paper or conducted further research into the impact of increased shipping traffic preventing the formation of new ice?
This is not my speciality, but is of great interest.
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now the traffic in Arctic  is not comparable with 70-th years.
I guess, useful data about ice producing  along shipping traffic could be done in AARI.
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Hi there,
I'm a marine researcher with Fisheries and Oceans Canada but I holiday/temp-work aboard private exploration mega yachts. We have a lot of phenomenal amateur footage (still and video) coming out of the Arctic (recently from two successful passes through the Northwest passage). For example, photography of 42 different polar bears.
Could this be of use to anyone's project?
For example, see the short doc: https://youtu.be/A1Qx8U6mu6A
Thanks,
Dr. Du Preez
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Do you have any footage of ringed seals?
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Dear colleagues,
In our ongoing research of Siberian ice-wedge polygon mires (http://www.pimdeklerk-palynology.eu/html/polygon_mires_-e_siberia-.html) I am currently working on a rather clastic profile from the Lena Delta that shows clear signs of cryoturbation in various profile trajectories. 
Of course the pollen data does not provide much information on the local vegetation development because of considerable homogenisation of the material, but I hope that it reveals some insights in the effect of cryoturbation on the sediment and pollen record, since it is also an important process of ice-wedge polygon development.
So now I am searching for other pollen data of such disturbed soils, but I have not yet found much. 
Does anybody of you perhaps know of studies that I could use for comparison?
Thanks and best wishes from Karlsruhe,
Pim
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Dear Pim,
I am sure you will get polen from your samples, but most probably you have to try different methods for your samples. I guess your samples should be Quaternary, Holocene or even Late Holocene, then you have to follow the recent developed methods for pollen recovery of these ages through internet or contact Quaternary pollen experts.
Wish you all the best.
Habib.
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I am trying to investigate on iceberg water. Why it is acidic (pH 5) and also what all tests I can carry out for better understanding of iceberg water. Any suggestions? 
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Icebergs are made then large pieces of ice break of glaciers. Glaciers are made from accumulated snow. As snow falls from the sky it doesn't contain any alkalinity (nor salt). Water without minerals to make alkalinity will always be slightly acidic due to the equilibrium with CO2 in the atmosphere to produce carbonic acid, H2CO3, in the water.
A pH of 5 is a bit lower than would be expected from the CO2 equilibrium with the atmosphere. The explanation might be that there are higher partial pressure of CO2 in the building you work in than the normal atmospheric CO2 concentration.
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By chance I recently found out about the project "The Changing Arctic Ocean: implication for marine biology and biogeohemistry." After reading the description of the project, I realized that it was very content coincides with my scientific activities. I have for many years engaged in the problems of changes in the biochemical regime of the Barents Sea, the relationship of these changes to the climate and biological processes in the Arctic. My Institute has the most complete in the World hydrochemical data base in the western Arctic. Potentially, we have the information in order to model the details of climate change, biochemical and biological processes in the Barents Sea over the last 50 years. Unfortunately, my institution and I personally do not have scientific contacts with scientists from the UK. Consequently, I could not find an opportunity to participate in the project.
If any of the participants in the project will be of interest to cooperate with me and my institution, I am ready to discuss the possibility.
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Thank you very much!
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Hello.
I tried to draw the Arctic arrows(set mproj nps) of u & v winds using the grads.
Data is NCEP/NCAR R1 regular grid 144x73, but it looks complicated.
Because, higher latitude of grid is continuously smaller and arrow spacing will be smaller from low to high latitude I think. Skip function was not helpful in grads.
If someone who know how can we draw Arctic arrows to be regular, please help me for this problem.
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You can use the "maskout" function in conjunction with "skip" to plot vectors at greater intervals at high latitudes.
First, generate a file (e.g., called "mask.dat") on the same grid as your data, but with values=1 for latitudes higher than some threshold (say, 75 deg. lat.), and values =-1 for latitudes less than that.
Next, create a new .ctl file (mask.ctl), with DSET mask.dat, using same XDEF, etc. as your real data, but with just 1 variable, e.g.
VARS 1
  mask 0 99 mask
ENDVARS
Then when running grads, "open mask.ctl".  This makes the mask array available as mask.2 .  First, plot the low-latitude vectors without any "skip" - excluding the high-latitude region with "-mask.2" (which has negative values at high lats):
d maskout(u,-mask.2);maskout(v,-mask.2)
Then plot the high-latitude vectors using "skip", excluding the low-lat region with "mask.2" (where neg. values are at low lats):
d skip(maskout(u,mask.2),4,4);skip(maskout(v,mask.2),4,4)
You will probably need to experiment a bit with "skip" values, and with threshold latitude.   
Note that "maskout" only applies to a gridded scalar field (like U, or V), not to the vector field, so the "skip" function must apply after any "maskout" used.
If you really wanted, you could use 3 or 4 different "masks" to select 3 or 4 different vector densities.
I hope you can make sense of all that. I just tried this myself on just a regular lat-lon grid, and at least it works on that okay.
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I am looking for a threshold levels of Hg in muscle or liver of the seabirds.
I found the publication of Dietz et al (2013) that provides information for eggs, but not for muscle of liver. Also the chapter in Demore et al (2005), but they do not present too much information for Hg in liver and muscle.
Dietz et al. (2013) What are the toxicological effects of mercury in Arctic biota?
Science of the Total Environment.
Demore et al (2005) Biological effects. AMAP Assessment 2002 : Heavy Metals in the Arctic 2005.
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Hi Jailson, 
As per the info of Stefania and Meredith above, there appears to be a lot of variability among species on effects.  You can check out papers by Joanna Burger and Birgit Braune and others, and you will find immense variability in the levels of Hg in wild seabirds, including some high levels.  There have been cause-effect studies, too (see Science of the Total Environment 2012  443: 775-790; Ecotoxicology 2012 21: 2143), but these are often on eggs and look at hatchability, etc.  There are far fewer studies that look at effects on adults.  A recent one in Environmental Science & Technology (2014) by Fort et al. showed lower investment in egg mass by Dovekies with high Hg levels.
Ultimately, I remain unaware of an absolute "threshold" level yet, at least for seabird liver or muscle, because seabirds seem more tolerant of Hg than other taxa.  Certainly some studies have shown high levels of Hg associated with deleterious effects on the birds, but mechanisms etc. in seabirds still need to be looked at.  Mark
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My question is specifically about the Arctic Ocean, not permafrost, not tropics, not global data. Also I need not just data (they are available), but analysis of satellite data, validity, etc for specifically Arctic Ocean.
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Yes, in Al-Buwaida- Ramtha- Jordan
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I am using Modis visible subsets and swath images with 250 m and 500 m resolution to visually characterize the occurrence of sea ice leads for specific regions in the Arctic.
Unfortunately the Images prior to 8 May 2012 are not available at the NASA websites anymore due to a hard disc failure and no solution of the problem is expected for the near future. Therefore I am looking for satellite imagery that is highly enough resolved to distinguish single sea ice leads.
My study period is March to April 2012. The regions are in the western Arctic north of Svalbard, Greenland, Ellesmere Island and in the Beaufort Sea.
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Hi Lukas, please check, whether the data presented at
might be an option for you and let me know in case you are interested. There will be an update for the missing years soon.
Best wishes,
Sascha
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Any suggestions about where to start to get the most recent breakthroughs? I am giving a presentation to the Tundra Conservation Network. When at AGU last month I already found some good leads but I wanted to test this scientific social network to see if I could really benefit from it!
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We just completed a special issue in Ecological Applications entitled "Trajectory of the Arctic" with several papers on this topic.
I hope these are of help to you.
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Just recently (April 26, 2013), scientists have been studying the excessive release of the element bromine in polar regions, indicating that this element comes from snow and ice. However, the bromine content of snow and ice is relatively low and although the whole polar ice cap releases bromine in the lower atmosphere, it is still not enough to cause severe depletion of the ozone. My question is, where do these large amounts of bromine in the lower atmosphere come from considering that polar regions are dense in carbon and not in bromine. It is interesting for me since bromine compounds are considered significant contributors to the depletion of ozone in the lower atmosphere, which is one of the most contentious topics in ecology.
Also, how are salts transported from the ocean and oxidized to become reactive halogen species in the air? And let's say, bromine explosion is a natural occurrence, and there are different reactivity of halogens as compared to OH and ozone, would the effect on the ozone be better or worse if other halogens, such as chlorine and iodine, are activated through mechanisms which are coupled to bromine chemistry?
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The bromine comes from bromide salts naturally present in ocean water, probably via sea spray. One point of the paper you mention is that the snow creates the interface - provides the OH- ions necessary, I assume - that converts the bromide into bromine gas - once there is sunlight (UV light). This typically occurs in the atmosphere, however the vapor content in the polar regions is extremely low due to the cold.