BG
Biogeosciences

Jasper Bloemen

Jasper Bloemen is a Post-doc researcher at the University of Innsbruck, Austria. He is currently PI on the project “The role of respired CO2 recycling in tree carbon allocation” funded by the Austrian Science Fund (FWF). After obtaining his PhD at Ghent University, Belgium in December 2013, Jasper moved to Innsbruck to continue his research on tree ecology. His main interests are tree carbon cycling and tree mortality. Currently Jasper is using stable isotope labelling combined with laser-based carbon isotope measurements to understand the role of carbon recycling in tree carbon allocation.

Understanding the role of microbes in cold seep habitats

Understanding the role of microbes in cold seep habitats

cold seep is an area of the ocean seafloor where hydrogen sulfide, methane and other hydrocarbon-rich fluid seepage occurs. These parts of the ocean floor still remain a large mystery for scientists, in particular for the occurence of hydrothermal vents. In between these vents, microbes live that play a role in the local and global carbon budget. However their exact role remains largerly unknown…

 

Microbes are globally distributed among different environments and catalyze most of the geochemical processes. In cold seep habitats, microbes anaerobically and aerobically oxidize released methane to convert it into carbonate in the sediments or into carbon dioxide above the seafloor respectively (Figure 1).

Fig. 1 Methane consumption by (i) anaerobic oxidation of methane, and (ii) aerobic methane oxidation. (Figure from James et al. 2016).

 

Their role in the global carbon budget is such that anaerobic activity below the seabed may prevent up to 80% of the methane released to reach the atmosphere. However, changes in oceanographic processes can influence the structure and the composition of these microbial communities, that remain poorly understood. These changes may have a cascade effect on the efficiency of methane oxidation. Recently developed methodologies and technologies in molecular biology, such as -omics techniques and fluorescence in situ hybridization, allow scientists to identify active microorganisms and genes associated to their metabolic activities. Additionally, microbes can be isolated through enrichment and cultivation methods. Cultures offer for instance opportunities to test resilience of these microbes to environmental changes, such as temperature and methane concentration variations.

References

James R.H., p. Bousquet, I. Bussmann, M. Haeckel, R. Kipfer, I. Leifer, H. Niemann, I. Ostrovsky, J. Piskozub, G. Rehder, T. Treude, L. Velstade, and J. Greinert. 2016. Effects of climate change on methane emissions from seafloor sediments in the Arctic Ocean: A review. Limnology and Oceanography. 61(S1): S283-S299.

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This blog post was written by Vincent Carrier. He is a PhD student at CAGE (center for arctic gas hydrate, environment and climate) in the University of Tromsø. He is a microbiologist, specialist in DNA analyses of the microbes in methane seep environments. His current research is about to characterize the methanotrophic bacterial communities and the communities responsible for the anaerobic oxidation of methane in different seep environments in the Arctic.

 

Identification of past methane emission altering the foraminiferal tests by secondary overgrowth of calcium carbonate.

Identification of past methane emission altering the foraminiferal tests by secondary overgrowth of calcium carbonate.

Ever heard about foraminifera? These tiny benthic (living at the seafloor) marine organisms are common in oceans across the globe and can be used to accurately give relative dates to sedimentary rocks. But we can also use them to identify past methane emissions from the seabed by studing their test or shell!  

The measurements were done on foraminifera called Cassidulina neoteretis , which is a typical species in Arctic environments and have a hyaline calcareous finely perforated wall that might be altered diagentically. Such diagenesis may occur when the tests experience seafloor methane seepage, of which the sampling was described in a previous blog post. Methane-derived authigenic carbonate (MDAC) crystals precipitate on the exterior and interior test walls, encrusting the test and allowing a detailed analysis of past methane emissions.

upper left: light microscope view of the foraminifera test. Foraminiferal tests having experienced major diagenetic alteration appear “frosty”, with low reflectance and transparency, and yellow to dark brown colour. Upper right: Backscatter Scanning Electron Microscopy image of the exterior test wall. The “frosty” appearance of the tests is caused by methane derived authigenic carbonate (MDAC) precipitation. Lower left: Backscatter-SEM image of a polished wall cross section. Solid MDAC crusts on the interior wall are up to 10 µm thick and appear slightly darker on electron backscatter images due to lower backscatter response of high-Mg calcite compared to foraminiferal calcite.Lower right: Correspondent Energy Dispersive X-ray Spectrometry image. The colour-change from green dominating on pristine foraminiferal calcite test towards a yellow-orange hue reflects higher Mg-content in the MDAC crust (Credit: Andrea Schneider, Centre for Arctic Gas Hydrate, Environment and Climate) .

 

The pictures show what we call the secondary overgrowth of calcium carbonate on these individuals. The benthic foraminifera are well known to calcify their shell in calcium carbonate, but because of the high methane concentration, there is a precipitation of methane-derived authigenic carbonate, which has precipitated on the foraminiferal shell. This is an evidence for past methane emission, which is important to quantify.

Reference:

Hesemann, M., 2017: Cassidulina neoteretis Seidenkrantz, 1995. In: Hesemann, M. 2017 Foraminifera.eu Project Database. Accessed at http://www.foraminifera.eu/single.php?no=1005695&aktion=suche on 2017-9-29


Dr. Pierre-Antoine Dessandier, post-doc researcher at CAGE, center for arctic gaz hydrate, climate and environment, university of Tromso, Norway wrote this blog post. After obtaining his PhD at Bordeaux university (France) in 2015 on micropaleontology, Pierre-Antoine moved to Tromso in Norway to continue his work on benthic foraminiferal ecology and paleo-environments. His main research interests are the use of benthic foraminifera as bio-indicators of climate change and methane emissions in the Arctic seas, using ecology of species and isotopic measurements. He is currently working on active methane seepages in the Barents Sea to reconstruct the chronolgy of the past methane emission and their link with climate change.

 

 

 

Investigation of methane emissions in marine systems

Investigation of methane emissions in marine systems
Ever wondered how we can measure methane emssions from the seafloor ? And ever wanted to steer a mini submarine remotely operating vehicle (ROV)? Well here´s your chance! Have look at this blog post on analyzing methane emissions using ROVs and you´re ready to embark! 

 

The goal is to determine when the gas leak started and how the fluid flow systems work. With our research, we can contribute to a better understanding at what time methane from the seabed has released to the atmosphere and if more emissions have occurred while the climate of the past was changing.

We have been using ROVs to inspect the seafloor and sample carbonate crusts, gas bubbles released from the seafloor and surrounding sediments (Fig. 1).

Fig. 1: the ROV Ægir 6000 (credit:Maja Sojtaric – CAGE).

The last area investigated is composed by two 2 small canyons where a lot of bacterial mats were observed (Fig. 2). These bacterial mats occur where the methane is in high concentration in sediments and represent a target for investigation on methane-influenced systems.

Fig. 2: sampling area in the Norwegian Sea and pictures of the seabed with bacterial mat (credit:Maja Sojtaric – CAGE ).

Two major tools are used in these environments to identify the past methane emissions, the carbonate crusts and push cores.The carbonate crusts precipitated because of the methane release, isotopes measured on these rocks inform about the date of emission and about the source of methane (Fig. 3 and 4).

Fig. 3: Gastropod in CH4-derived carbonate cemented sediment; aragonite botryoids (upper center; X-pol light) (credit: Maja Sojtaric – CAGE).

The push cores are sampled for porewater to trace geochemical processes related to fluid flow processes. Samples are also taken for gas measurements to determine the amount and its sources (Fig. 4). The response of the biological community on methane seepage is analyzed by means of planktonic and benthic foraminifera.

Fig. 4: Push core sampling in bacterial mat (credit: Maja Sojtaric – CAGE).


Dr. Pierre-Antoine Dessandier, post-doc researcher at CAGE, center for arctic gaz hydrate, climate and environment, university of Tromso, Norway wrote this blog post. After obtaining his PhD at Bordeaux university (France) in 2015 on micropaleontology, Pierre-Antoine moved to Tromso in Norway to continue his work on benthic foraminiferal ecology and paleo-environments. His main research interests are the use of benthic foraminifera as bio-indicators of climate change and methane emissions in the Arctic seas, using ecology of species and isotopic measurements. He is currently working on active methane seepages in the Barents Sea to reconstruct the chronolgy of the past methane emission and their link with climate change.

 

 

 

What´s in your fieldbag? Part 1: measuring freshwater carbon fluxes in the Artic

What´s in your fieldbag? Part 1: measuring freshwater carbon fluxes in the Artic

This bag belongs to

Joshua Dean, Postdoc, Vrije Universiteit Amsterdam

Field Work location

Far Eastern Siberian Arctic: Kytalyk Nature Reserve.

Duration of field work

2 weeks plus 3 days travel either side.

Items in the bag

  • Detecto Pak-Infrared (DP-IR) gas analyser [borrowed from colleagues, protect at all costs]
  • EGM4 CO2 gas analyser [borrowed from another department, protect at all costs]
  • water sample vials [plus many tens of spares]
  • molecular sieve cartridges [for capturing CO2 samples for radiocarbon analysis; Garnett et al., 2016a]
  • foil gas bags [for capturing CH4 for radiocarbon analysis; Garnett et al., 2016b]
  • small and large syringes, needles and stopcocks [for extracting dissolved CO2 and CH4 samples from water]
  • jumbo (1L) syringe [for extracting jumbo water headspace samples for CO2 and CH4 radiocarbon sampling – also good for jumbo sized practical jokes]
  • drink bottle [I normally bring a camelback] and snacks
  • satellite phone [T‑mobile’s Siberian Arctic coverage is woeful]
  • ski goggles as gift for Russian park ranger [so they will show me the protected mammoth graveyards in the nature reserve]
  • waterproof notebook [to protect from the elements and clumsiness]
  • duct tape [or duck tape depending on your tastes]
  • sharpie/permanent markers [2 things you always need in the field, duct tape and permanent markers – always! It’s best if these are colour coded so you know if someone has stolen yours].
 The essentials for aquatic greenhouse gas field sampling campaigns (photo credit: Joshua F. Dean, VU Amsterdam)

The essentials for aquatic greenhouse gas field sampling campaigns (photo credit: Joshua F. Dean, VU Amsterdam)

 Not shown in photo

  • exetainers® [for storing gas samples extracted from water]
  • jumbo degassing vessel(s) [to match the jumbo syringe, see Garnett et al., 2016a and 2016b for more details]
  • assorted spare parts [many, many, many spare parts – finding small bits of equipment that you dropped in the Arctic tundra is a nightmare, I lost a walkie-talkie in the tundra once]
  • field team [for mental and physical assistance – absolutely vital
  • Russian guide [because English is not to be found here]
  • mosquito shirt and bug spray [the mosquitos love foreign blood, for an impression see below]
  • spare food [in case you have an aversion to weird food, see previous post on the Blog].

 

Post_Josh_Dean_Mosquito_paradise

Mosquito Paradise, Kytalyk Nature Reserve (photo credit: Ove H. Meisel, VU Amsterdam)

Aim of the research

The aquatic pathway is known to be a potentially important export pathway of terrestrial carbon of all forms (Dinsmore et al., 2010), but while this is known to be a significant process in the Arctic (Vonk et al., 2015), we desperately lack in understanding of how this may be affected by the warming climate. We are taking measurements of freshwater carbon fluxes across a range of lakes, pools, rivers and streams in the Siberian Arctic tundra to estimate their contribution to the carbon budget of the landscape. We will compare this to measurements from the eddy covariance tower, both CO2 and CH4 fluxes, that we manage at the site (see previous post on the blog). We are also incorporating radiocarbon measurements within this to see whether climate change induced permafrost thaw is mobilising ancient carbon, which was previously locked up in the organic rich tundra soils, into the aquatic pathway.

One item I can’t live without

Beer… I can live without it, but when everything goes wrong in the field, you fall into a pool and/or stream, your camera gets wet, the batteries in all your equipment die, you lose repeated samples and the mosquitos have laid waste to every inch of your skin, it’s nice to relax with an ice cold beer in the evening. Luckily the permafrost in this area is shallow, so it’s easy to dig a temporary fridge.

References

Dinsmore, K.J., Billett, M.F., Skiba, U.M., Rees, R.M., Drewer, J., Helfter, C., 2010. Role of the aquatic pathway in the carbon and greenhouse gas budgets of a peatland catchment. Global Change Biology 16(10), 2750–2762.

Garnett, M.H., Gulliver, P., Billett, M.F., 2016a. A rapid method to collect methane from peatland streams for radiocarbon analysis. Ecohydrology 9, 113-121.

Garnett, M.H., Billett, M.F., Gulliver, P., Dean, J.F., 2016b. A new field approach for the collection of samples for aquatic 14CO2 analysis using headspace equilibration and molecular sieve traps: the super headspace method. Ecohydrology, doi:10.1002/eco.1754.

Vonk, J.E., Tank, S.E., Bowden, W.B., Laurion, I., Vincent, W.F., et al., 2015. Reviews and synthesis: Effects of permafrost thaw on Arctic aquatic ecosystems. Biogeosciences, 12, 7129-7167.


Dr. Joshua F. Dean from the VU University Amsterdam wrote this blogpost. He is a postdoctoral researcher who explores the carbon cycle in the Arctic and temperate peatlands to determine methane and carbon dioxide feedbacks under a warming climate. His work involves experimental approaches, modelling, and direct and indirect measurements of carbon dioxide and methane emissions from freshwater environments, with fieldwork campaigns throughout the Arctic and northern hemisphere peatlands.

Coffee break biogeosciences – climate change affects mountain plant’s sex ratios

Coffee break biogeosciences – climate change affects mountain plant’s sex ratios

As climate change progresses, widespread changes in phenotypes in many plant populations are bing observed by scientists around the world. For instance in alpine areas, dominant plant species on lower altitude are shifting towards higher altitude as they adapt to increasing temperatures, thereby competing with high-altitude native plant species. In a recent study by Petry et al. (2016) it was shown that responses to climate change in the plant Valeriana edulis (valerian) are strongly sex-specific, thereby reducing pollen limitation and increasing seedset under climate change scenarios. By comparing the presence of female and male valerian plants at different elevations (from 2500 to 3600m) along slopes in the Rocky Mountains of Colorado, they found that climate change is impacting the sex ratio of plants along their elevation range, with a higher presence of female plants high on the mountain as compared to male plants. As these ratios of female to male plants are changing faster than species are moving uphill, they might be a much more rapid trait to detect responses of plant communities to climate change than migration patterns.

To read more about this research on how warming alters mountain plant´s sex rations in the Rocky mountains, check out the article by Petry et al. (2016).

Keeping a lookout at the edge of the world

Keeping a lookout at the edge of the world

 

Few places in the world conjure up images of remoteness and harshness like Far Eastern Siberia. Yet, it’s places like these where our science is needed most.

Arctic soils hold vast amount of carbon, protected in thick layers of permafrost, but these stores are becoming more and more vulnerable as temperatures in the Arctic warm, and are set to warm faster than anywhere else on the planet. Recent studies have further suggested that the freezing and thawing activity in permafrost areas plays a crucial role in the overall carbon balance of these regions, trapping and releasing large quantities of gas in unfrozen, still active soil layers during the shoulder seasons (e.g. Zona et al., 2016). Hence the challenge to measure C fluxes in these regions during the early spring and late autumn periods either side of the snow-free growing season.

However, just getting to these sites is often a challenge, both logistically and personally!

I recently travelled to Siberia in April with my boss to set up eddy covariance instrumentation at our Arctic Siberian field site – Kytalyk nature reserve, about 30 km northwest of Chokurdakh, a small town itself a three-and-a-half-hour flight (on a plane that was two generations older than me) northwest of Yakutsk in the Sakha Republic of Russia. Our research group, led by Prof. Han Dolman at Vrije Universiteit Amsterdam, has been measuring carbon fluxes at the site since 2003. This year I took on the reigns of these measurements, a long way from my home country of New Zealand, and it was more challenging than I expected…

Picture_1_graph

Our long-term record of CO2 fluxes from the Kylalyk site in Arctic Siberia, one of just a handful of such “lookout posts” in the vulnerable Arctic (photo credit: Luca Belelli Marchesini).

 

During my interview for this position, I was asked to respond to a riddle:

“You are in the field with a team of Russians, they have been drinking vodka and are very drunk. An emergency arises, and you need to get everyone to safety. What do you do?”

Whilst carefully refraining from explaining that if everyone else was drinking vodka, I probably would have been too, I managed to find an answer that must have been acceptable because I got the job. This question was just a taster for the unique encounters you can experience while doing fieldwork in new and wonderful places.

Siberian Russia is not the most culturally divergent place from what I am accustomed to, and I’m sure there are many readers who have been to more wild regions and eaten more outrageous cuisine. But I wanted to share some of my experiences for those of you who may have to follow a similar path involving cultural and culinary experiences that you might otherwise not seek out in your daily life.

I’m not a big fan of fish, for instance, certainly not raw fish. Raw fish happens to be the go-to protein dish in this part of Siberia. A particular treat is the Indigirka Salad, cubes of frozen raw fish and onions – the ultimate challenge for any breath freshener.

I was also to enjoy boiled tongue (I’m not sure whose) in creamy, custard-like sauce, and soup made primarily from cow stomach and entrails. It smelt as bad as it sounds, something like a cross between cow burps and a pig’s fart, and the meat looked exceptionally disturbing.

 

Cow stomach soup: best served not at all (photo credit: Joshua Dean).

Cow stomach soup: best served not at all (photo credit: Joshua F. Dean).

 

Out at the field site I would eat plenty more frozen fish, but cut directly from the fish itself and dipped in instant noodle flavouring. This was quite tasty if you ate it fast enough not to notice the texture of raw fish melting in your mouth. I would also drink fermented horse milk, and eat jelly made from bone marrow. A cube of the latter is enough to make you see your breakfast again under the right circumstances, unless you have vodka to wash it down.

My advice here? Don’t be afraid to try new things, but don’t be afraid to say no if it tastes like an unwashed cow’s anus and vomiting isn’t high on your agenda for the day.

Taking a sled ride behind a snowmobile as we headed into the remote and snowy Arctic was also an amazing experience, but after an hour of riding in a sled with no suspension, the majority of your bones will eventually turn into a fine powder, as shown here.

During our stay in the field we celebrated Koningsdag, the Dutch King’s Birthday (27th April – also my birthday, though I didn’t convince anyone that I was royalty), by flying a Dutch flag over a small piece of the Russian Arctic (this was not meant as an act of geopolitical aggression).

 

Picture_3_Dutch_flag

Definitely not conquering the Russian Arctic, Joshua Dean on the left, Han Dolman on the right, with the (not yet working) eddy covariance tower in the background (photo credit: Joshua F. Dean).

 

At the site, setting up the eddy covariance tower proved to be relatively straight forward. However, we first found that we weren’t collecting data from the sonic anemometer (measuring wind speed and direction in three-dimensions). It turns out we hadn’t turned it on (duh!) leading to the discovery that the solar panels and batteries weren’t working. Some MacGyver-like electrical combos later and we had the system up and running. Success! But a good example of how inventive you have to be to fix things when backup gear is literally half a world away.

Back in Yakutsk we relaxed with a banya (a Russian Sauna), which includes plenty of beer, hanging out naked with your boss, and a thorough birch branch whipping by a 60-something Russian professor.

The generosity of our Russian hosts was unsurpassed. While the food certainly pushed some of my culinary boundaries, I’m pretty sure our hosts found my myriad reactions to their food and drink highly amusing. I look forward to visiting again in the summer for more fieldwork, and to strengthen the bond of social and scientific collaboration that started with a mouthful of cow guts.

Reference: Zona, D. et al. (2016) Cold season emissions dominate the Arctic tundra methane budget. Proceedings of the National Academy of Sciences 113(1):40-45.


Dr. Joshua F. Dean from the VU University Amsterdam wrote this blogpost. He is a postdoctoral researcher who explores the carbon cycle in the Arctic and temperate peatlands to determine methane and carbon dioxide feedbacks under a warming climate. His work involves experimental approaches, modelling, and direct and indirect measurements of carbon dioxide and methane emissions from freshwater environments, with fieldwork campaigns throughout the Arctic and northern hemisphere peatlands.

Coffee break biogeosciences – New coral reef at Amazon river mouth discovered

Coffee break biogeosciences – New coral reef at Amazon river mouth discovered

At the Amazon river mouth, a huge 9,300 sq km coral reef system has been found below the muddy waters off the mouth of the river Amazon. As corals mostly thrive in clear, sunlit, salt water, and the waters near the mouth of the Amazon are some of the muddiest in the world, the discovery of this almost 2000 km long reef leaves scientists puzzled about the potential extent of coral reefs worldwide.

To find out more about the coral reef at the Amazon river mouth, read  the article by Moura et al. (2016).

 

 

General assembly 2016: our session picks

General assembly 2016: our session picks

Whether you’re an experienced attendee of the EGU GA, or this is your first time there are always things to look out for, it is always worth attending your division’s division meeting, one of the great debates, and keep an eye out for short courses which may be of interest to you. Here are the recommendations from the Biogeosciences Blogging team:

The BG division meeting is Thursday from 12:15-13:15 in Room 1.61.

One short course that could be of interest is Analytical techniques for revealing the nature and chemical properties of natural organic matter on Friday 12:15–13:15 in Room 2.61

Another is Experiments in Geosciences Monday 10:30-12:00 in Room 2.97.

If your work involves samples acquired by drilling the “ICDP-IODP Town Hall meeting” on Tuesday 19:00-start in room G2 could be highly informative.

There are a number of workshops discussing different funding opportunities including the “European research council funding opportunities” on Tuesday with a 19:00 start in room 2.85.

On Wednesday starting at 12:15 is the EGU Early Career Scientists’ Forum in Room L7. One of our contributors (Rachael) is interested in Deep Life, especially in hard rocks.So she is interested in:

  • Monday 8:45-start session entitled “Climate extremes, ecosystems and dynamic landscapes controlling biogeochemical cycles” in room M1
  • Monday 17:30-start session “Fluid circulation in magmatic hydrothermal systems” in room L7

If any of your work involved CO2 storage the session on Thursday starting at 13:30 in Room 2.31 entitled “Field methods and analysis of field data for CO2 geological storage” could be interesting.

If you’re more into climate change related topics such global change ecology, one of our other contributors (Jasper) has some good picks for you:

  • Session about climate extremes and their impact on biogeochemical cycles- monday from 10:30-12:00, room M1
  • Session on the use of plant traits to understand changes in biogeochemical cycles – wednesday from 10:30-12:00, Room M
  • Always wondered how carbon is allocated in plants and ecosystems? If yes, go to the session on plant carbon allocation, 15:30-17:00, room M1
  • How can we use tree rings to understand responses of trees to climate change – thursday from 08:30-10:00, Room 0.3

Finally, it is always interesting to attend at least one session that is completely out of your comfort zone, so you can find out that some scientists are investigating even crazier things than you are currently doing. Our bet for this year’s general assembly: Mars science and exploration! Monday and tuesday from 8:30-10:00, room E1


Post written by Rachael Moore and Jasper Bloemen

Digging up bones for science – looking into 48 million years old blood vessel-like structures

Digging up bones for science – looking into 48 million years old blood vessel-like structures

The Messel Pit is a worldwide famous fossil site recognized by UNESCO as a World Natural Heritage Site because of the exceptional preservation, as well as the diversity of its fossils from the early-middle Eocene (~48 Ma). The Messel Pit, located in an old Quarry in Germany near Frankfurt am Main , includes fossils from vertebrates (turtles, crocodiles, mammals, birds, lizards, among others), invertebrates (insects), and plants. The vertebrates are preserved in articulation, often with associated ‘‘soft ’’ tissues such as hair, scales or feathers, and even occasionally in situ stomach contents. Despite of the exceptional macroscopic (complete skeletons) preservation of Messel Pit vertebrates, the internal preservation of bones has been almost completely unexplored, leaving unresolved questions as for example if such exceptional preservation also occurs at microscopic and molecular level, allowing the recovery of bone proteins and even DNA.

A new research topic was started at the Senckenberg Museum in Frankfurt, focused on examining the preservation of blood vessels and bone cells-like (called osteocytes) from some of the Messel pit vertebrates. Osteocytes are remarkably important for understanding evolution since they are the most abundant cells forming bones in all vertebrates on Earth. After analysing very small pieces of fossil bones (less than 1 cm2), beautiful osteocytes-like and blood-vessels-like from two species of turtles, one mammal species, and one crocodile were discovered. It thus indicated that the exquisite preservation of Messel Pit vertebrates occurs at both macro (skeletons) and micro (cells-like) scales.

Fig_Cadena_1

Step by step illustration of osteocytes-like cell analysis. Top-left (fragments less than 1 cm3 of bone from Messel pit vertebrates were taken for analysis). Middle-left (all the mineral phase of the bone are removed, leaving after only the osteocytes and blood vessels-like microstructures). Bottom-left (osteocytes and blood-vessels-like are observed and photographed using a light-transmitted microscope. Bottom-right (osteocytes are also observed under Field Emission Scanning Electron Microscope, to explore in detail their textures and physical properties) (Credit: Edwin Cadena, Senckenberg museum)

However, work on these bone osteocytes and blood vessels-like microstructures is not quite complete. It is also interesting to establish if there are any remains of their original molecular composition (proteins or even DNA) after 48 millions years of being trapped inside the rocks. Preliminary results show that osteocytes-like and blood vessels-like exhibit important amount of iron (Fe) in their composition, contrasting with bone remains and collagen fibrils-like that lack iron. Although no proteins or DNA remains have been found yet in the Messel Pit fossil vertebrates, the occurrence of iron is a good signal because iron has also been found in similar microstructures of dinosaurs bones from USA, in which proteins are truly preserved.

Fig_Cadena_2

Analysis of the elemental composition of one of the osteocytes-like cells from a fossil turtle from Messel Pit, using a Phenom Pro X Scanning Electron Microscope. Red dots on the osteocytes indicate different spots that were analysed for compositional elements, as shown for example for spot 2, indicating a high content of iron (Fe), Carbon (C), and Oxygen (O2) (Credit: Edwin Cadena, Senckenberg museum).

 

At this point, it is clear that further research is needed for establishing the original biomolecular composition (amino acids and proteins) of fossil cells or soft tissue. If bone proteins – or even DNA- are preserved in Messel Pit fossils that could shed light on understanding evolutionary relationships, as well as the mode and rate of evolution at molecular levels, which is crucial for explaining different lineages of extant vertebrate animals, including us.

 

 

For further details, see Cadena (2016).

Reference:Cadena, E.A. 2016. Microscopical and elemental FESEM and Phenom ProX-SEM-EDS analysis of osteocyte- and blood vessel-like microstructures obtained from fossil vertebrates of the Eocene Messel Pit, Germany. PeerJ 4:e1618; DOI 10.7717/peerj.1618

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Dr. Edwin Cadena wrote this blogpost. He got a grant from the Alexander Von Humboldt foundation to perform his research on osteocytes from fossilized (in)vertebrates at the Messel Pit.

Coffee break biogeosciences – using truffle dogs for science!

Coffee break biogeosciences –  using truffle dogs for science!

Coffee break biogeosciences, your bi-weekly biogeoscience cake to accompany your coffee…

Do you remember your last scientific conference? Did you also find the scientific coffee break discussion as interesting as the scientific talks? If yes, these short blog posts will allow you to keep the interesting coffee break discussions going as we´ll give you on a bi-weekly basis your scientific biogeoscience cake to accompany your coffee…

Mushrooms are considered perfect bio-indicators of environmental pollution. For instance, some forest mushrooms can accumulate high levels of radioactivity if the soil is contaminated with radioactive nuclides like caesium-137 (137Cs) and 90-strontium (90Sr). In a recent paper published in Biogeosciences (Büntgen et al., 2016), an open access journal of the European Geoscience Union, Swiss and German researchers analyzed truffles collected at different spots in central Europe and found that they contained insignificant amounts of 137Cs, hence being fit for human consumption.

In 1986, the Chernobyl nuclear disaster in Ukraine released substantial quantities of radioactive particles, especially 137Cs. Transported by winds and deposited by heavy rainfall, 137Cs polluted large parts of the European continent, leaving much of the continent’s topsoil layers still radioactively contaminated 30 years later. To date it remained unclear whether truffles accumulate radioactivity at a harmful level comparable to other fungal species. The researchers collected with the help of trained dogs Burgundy truffles in several natural habitats and plantations in Switzerland, Germany, France and Italy. The collected truffles contained negligible amounts of radioactivity, with 137Cs values ranging below the detection limit of 2 becquerels per kilogram (Bq kg -1). This is far below the tolerance value of 600 Bq kg-1, meaning the truffles are safe for consumption, at least in the areas the researchers sampled from. Therefore, if you´re having a headache after eating truffles in your local Italian restaurant, don´t blame the truffles but rather suspect the waiter, who overcharged you for a plate of pasta with fungi (on top of the bottle of Chianti wine).

Citation:
Büntgen, U., Jäggi, M., Stobbe, U., Tegel, W., Sproll, L., Eikenberg, J., and Egli, S.: All-clear for gourmets: truffles not radioactive, Biogeosciences, 13, 1145-1147, doi:10.5194/bg-13-1145-2016, 2016.

http://www.biogeosciences.net/13/1145/2016/