A new paper describing and interpreting a new crinoid from the Upper Ordovician of Estonia

I am very pleased to announce that Lena Cole, Bill Ausich, and I have a new article that appeared (on a dramatic election day in the USA!) in Papers in Palaeontology: “A Hirnantian holdover from the Late Ordovician Mass Extinction: Phylogeny and biogeography of a new anthracocrinid crinoid from Estonia.” Lena was our leader and did a fantastic job with the description and analysis. In fact, it was the easiest peer review process I’ve ever seen. Above you meet the star specimen, the calyx of Tallinnicrinus toomae gen. et sp. nov., an anthracocrinid diplobathrid crinoid. The new genus is named after Tallinn, the beautiful capital of Estonia. The species is named after our excellent Estonian colleague Ursula Toom.

The abstract: Relatively few Hirnantian (Late Ordovician) crinoids are known, and none has been previously described from the palaeocontinent of Baltica. This has impaired our ability to understand the patterns of extinction and biogeographic dispersal surrounding the Late Ordovician mass extinction, which triggered a major turnover in crinoid faunas. Here, we describe Tallinnicrinus toomae gen. et sp. nov., an anthracocrinid diplobathrid from the Hirnantian of northern Estonia. Tallinnicrinus is the youngest member of the Anthracocrinidae and the first representative of the family to occur in Baltica. Morphologically, Tallinnicrinus is unusual in that the radial and basal plates are in a single circlet of 10 plates, similar to the anthracocrinid Rheocrinus Haugh, 1979 from the Katian of Laurentia. Phylogenetic analysis further confirms a close relationship between Tallinnicrinus and Laurentian anthracocrinids, suggesting biogeographic dispersal of the lineage from Laurentia to Baltica during the late Katian or early Hirnantian. The occurrence of this new taxon establishes that the family Anthracocrinidae survived the first pulse of the Late Ordovician mass extinction. However, the lineage remained a ‘dead clade walking’ because it failed to diversify in the wake of the end-Katian extinction and ultimately went extinct itself by the end of the Ordovician.

Above is Bill Ausich talking to Ursula during our visit to Tallinn in August 2018. We are in the collections of the Department of Geology, Tallinn University of Technology.

The College of Wooster and The Ohio State University geology programs have had an excellent relationship with Estonian geologists for many years, for which we thank Olev Vinn, who invited me to his lovely country many years ago. Many Wooster and OSU students have done field and laboratory work there, and we now have numerous joint publications. We look forward to visiting again once the COVID-19 pandemic abates.

Reference:

Cole, S.R., Ausich, W.I., and Wilson, M.A. 2020. A Hirnantian holdover from the Late Ordovician Mass Extinction: Phylogeny and biogeography of a new anthracocrinid crinoid from Estonia. Papers in Palaeontology (early view)

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An October Day at Fern Valley – The Mass Movement

A day at Fern Valley with a team of experts, from the left Dr. Judge, Nick and Arrow, Morgan and Ellen. The mission was to map the Fern Valley Slump (and Ellen took a bunch of tree cores from the second (or third) growth oaks).The slump from above. Note the arcuate scarp that marks the upper reaches of the slump block – a series of grabens and scarps stair-step their way into the valley.

Nick has installed wells in the slump blocks to monitor the pore water pressure of the materials.
Here Dr. Judge and Morgan decide where the boundaries of the block are located and then use the Trimble to gather the points.

The team standing at the head of the slump devising a three-part plan of attack.

Another monitoring strategy is the game camera in the tree, which has kept an eye on the movement for the past 8 years.

Morgan and Nick measure the water level in the lower well at the base of the slump.

The hillslope hydrology at the site is complex with much of the flow moving through natural through flow pipes.

The pipes are developed in the reddish sand layer at the base of a legacy (eroded soils) layer (bluish).

One of the well developed pipes in a sand and gravels layer. Note the oxidation of the water as they emerge. Oxidation is facilitated by the bacterial slime that forms at the exits of the pipes.

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Celebrating #BlackInGeosciences Week: Finding My Voice

Guest Blogger:  Mazvita Chikomo (’22)

Mazvita, a junior in the department from Zimbabwe, is a member of the African Student Union (Housing Coordinator), has participated in the college’s AMRE program (Applied Methods Research Experience), has been a Course Design Assistant for Dr. Wiles, and is currently an APEX Peer Mentor assigned to Dr. Judge’s FYS class. 

 

This week, in light of #BlackInGeo Week, I get the opportunity to talk about my experience as a Black student in the Earth Sciences Department. In no shape or form can I talk about the universal experience of being Black in the department, but I can talk about my personal experience and journey.

When I think about my journey through the Earth Sciences Department, I think of times being alone, and then I think of strength, growth, and family. As a freshman, I did not really realize I was one of a few Black people in the major because introductory classes were flooded with students from different majors. But once I started to pursue higher courses for the major, I began to see fewer and fewer people who looked like me. Because of this, I initially found it difficult to insert myself in my classes. I would do the required work and pass the required exams, but I was scared to actively be engaged because I felt I had the duty to speak for many. It was daunting to think that I was responsible for bringing an under-represented perspective. And I was scared to make a mistake, so perfection was the only level of excellency that I had to strive for.

 I thought the secret to never make a mistake is to never actively try right, but soon I realized it was not realistic for me to set a goal to always be my best self. I did not have to carry the weight on my shoulders; when I came to class, I needed to just be myself. By not actively participating, I realized I was doing a disservice to myself because I did not give myself the grace of learning from my failures. And I did not allow my peers to hear my perspective and my voice, not the voice of a Black girl from Zimbabwe, but the voice of Mazvita. I did not have to come to class with all the answers. I also did not have to answer every question. I just had to be me. This journey of self-discovery in the department was made easier by the lovely faculty of the department. They were always encouraging me to never shy away from participating. They gave me the confidence to lead discussions when I wanted to and were constantly there to talk to me if I wanted to. I also appreciate my peers because when I did want to speak, they gave me the space to have my voice heard. When the pandemic began, the first people to reach out to me were members of the department. But this is not to say everything in the department is sun and roses; we still have a lot of growth needed in the department. It would be nice to one day see Black faculty in the department. Sometimes the reassurance a student needs is being able to see people who look like them in positions of leadership.

 My dream is to see an Earth Sciences Department rich in diversity. If I were to give any advice for Black students and minorities in the department, never be afraid to let your voice be heard. There is power in your voice and mind but be sure to grow in your own time and space. There is no rush to be like anyone else. Be you! This can start by setting small goals for yourself; maybe today you’ll raise your hand, or perhaps tomorrow you’ll say hi to someone you’ve never talked to in class. I myself am still growing and learning and look forward to meeting and seeing more Black people in the department.

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New Paper: Quantifying ecospace utilization and ecosystem engineering during the early Phanerozoic — The role of bioturbation and bioerosion

I am thrilled to announce the publication today of this comprehensive open-access paper in Science Advances: “Quantifying ecospace utilization and ecosystem engineering during the early Phanerozoic — The role of bioturbation and bioerosion“. It was a long time coming after a massive data collection and analysis project led by the indefatigable and highly productive team of Luis Buatois and Gabriela Mángano (University of Saskatchewan). We even have a news release. (Above image: Trace fossils in the Early Cambrian Gog Group, Lake Louise, Alberta, Canada. See earlier blog post for details.)

The abstract —

The Cambrian explosion (CE) and the great Ordovician biodiversification event (GOBE) are the two most important radiations in Paleozoic oceans. We quantify the role of bioturbation and bioerosion in ecospace utilization and ecosystem engineering using information from 1367 stratigraphic units. An increase in all diversity metrics is demonstrated for the Ediacaran-Cambrian transition, followed by a decrease in most values during the middle to late Cambrian, and by a more modest increase during the Ordovician. A marked increase in ichnodiversity and ichnodisparity of bioturbation is shown during the CE and of bioerosion during the GOBE. Innovations took place first in offshore settings and later expanded into marginal-marine, nearshore, deep-water, and carbonate environments. This study highlights the importance of the CE, despite its Ediacaran roots. Differences in infaunalization in offshore and shelf paleoenvironments favor the hypothesis of early Cambrian wedge-shaped oxygen minimum zones instead of a horizontally stratified ocean.

In short, this is a study of trace fossil occurrences during the Ediacaran, Cambrian and Ordovician periods. Trace fossils are evidence of organism activity, so we are looking at the early evolution of animal behavior in space and time. The paleoenvironmental conclusions include support for Early Cambrian laterally discontinuous, wedge-shaped oxygen minimum zones, which have implications for Cambrian community development.

The illustrations in this paper do not fit well into this blog format. The above is part of Figure 2, a plot of changes in modes of life (ML), ecosystem engineering (EE), maximum alpha ichnodiversity (AI), global ichnodiversity (GI), and ichnodisparity (Id) in all environments. Counts are plotted at the middle of the series intervals.

Another portion of Figure 2 showing some of the ecospace patterns. Since the paper is open-access, you can click here for the originals.

Note that the data for this work came from 1367 stratigraphic units. This paper is thus based on generations of geological and paleontological articles. It is affirming to know that hundreds of small, local descriptive studies eventually add up to major evolutionary and paleoenvironmental models. Several of those projects were done by Wooster faculty, students, and alumni. Some of the earlier comprehensive data gathering and analysis can be found in Buatois et al. (2016) and Buatois et al. (2017).

My primary job on this international team of scientists was to join with Max Wisshak (Marine Research Department, Senckenberg am Meer, Wilhelmshaven, Germany) to sort out the bioerosion data and patterns. (Bioerosion is the biological abrasion of hard substrates such as rocks and shells.) Max generally focused on microbioerosion and I mostly did macrobioerosion. We showed that bioerosion had a dramatic increase in diversity during the Ordovician, probably because hard substrates like shells and hardgrounds became more available.

This was an exciting project. I look forward to future applications of the data and methodology we employed in this work. There are many opportunities for Wooster Independent Study students here. Thanks again for the leadership of Luis Buatois and Gabriela Mángano.

References:

Buatois, L.A., Mángano, M.G., Minter, N.J., Zhou, K., Wisshak, M., Wilson, M.A. and Olea, R.A. 2020. Quantifying ecospace utilization and ecosystem engineering during the early Phanerozoic — The role of bioturbation and bioerosion. Science Advances 6: eabb0618.

Buatois, L.A., Mángano, M.G., Olea, R.A. and Wilson, M.A. 2016. Decoupled evolution of soft and hard substrate communities during the Cambrian Explosion and Great Ordovician Biodiversification Event. Proceedings of the National Academy of Sciences U.S.A. 113: 6945–6948.

Buatois, L.A., Wisshak, M., Wilson, M.A. and Mángano, M.G. 2017. Categories of architectural designs in trace fossils: A measure of ichnodisparity. Earth Science Reviews 164: 102–181.

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Coring Trees on Chicagof Island, Hoonah, Alaska

We had the good fortune this summer to work remotely with the TRAYLS group out of Hoonah, Alaska.

Figure 1. Google Earth map showing the location of the town of Hoonah and the coring sites. Two tree ring sites were sampled by the group the HN site in the town and the EAR site on Ear Mountain.

Arianna Lapke lead a group of four participants through an ambitious set of projects over much of the summer. Our collaboration with the group centered on meeting virtually with the group to describe the utility and sampling of trees for dendroclimate information. Below are the results of their sampling on EAR Mountain, Chicagof Island and our lab work at the Wooster Tree Ring Lab.

The group shown coring a Sika spruce just outside of town.
More coring – this time in the rain.

The steep climb up the flank of Ear Mountain to find the old Mountain Hemlocks.

Comparisons of the fast growing Sitka Spruce and the slow growth of the higher elevation Mountain Hemlock.

The cores from the hemlock some over 400 years old show lots of stress , clinging to the mountain side and battered by storms. They are also showing a possible drop in ring-width over time 

So we measured the ring-widths (Nick Wiesenberg and Melita Wiles did) and then we compiled the ring-width data into a chronology aboveThis chronology is the full record going back into the 16th century

This chronology is truncated at 1720 or so when we had at least 4 samples. The most narrow rings follow the 1808 unknown eruption that cooled much of the region – it is unknown as no one knows where the volcano that erupted is located – it is recognized in ice cores.  The other intriguing feature is the relatively recent (last 50 year) drop in ring widths.  It may be due to increased evapotranspiration demands with increasing summer minimum temperatures.  There is a correlation of -0.39 (p<0.04) between tree growth and average April-August minimum temperatures. Other studies have shown that warming night time temperatures lead to increased respiration at night and along with possible greater ET demand or increased cloudiness during the day there may be a decrease in photosynthesis leading to  decreased carbon uptake (Sullivan et al., 2015). Interestingly, tthe work of Mazvita Chikomo done this summer as part of the AMRE project, discovered some pretty strong negative correlations between Mt. Hemlock growth and minimum monthly temperature records in Prince William Sound – perhaps there is a link? This is a promising line of research to further investigate the health of Mt. Hemlock in the region and it is something we plan to pursue with more samples in the future. 

Reference cited:
Sullivan, P. F., Mulvey, R. L., Brownlee, A. H., Barrett, T. M., & Pattinson, R. R. (2015). Warm summer nights and the growth decline of shore pine in Southeast Alaska. Environmental Research Letters, 10 124007.

Acknowledgements: We thank Arianna Lapke and the TRAYLS group and look forward to future work with them. This work was supported by the Sherman-Fairchild Foundation, The Luce Funds and the National Science Foundation. NSF Grant AGS 8001184 supported Julia Pearson, Claire Cerne, Ben Gaglioti and Greg Wiles. We also acknowledge the contributions of AMRE participants – Mazvita Chikomo, Srushti Chaudhari and Fred Whenshuo.

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AMRE Summer 2020 – Remote Learning and Tree Rings – Part 1. The Oaks at the Kinney Soccer Fields, Wooster, Ohio

By: Mazvita Chikomo, Srushti Chaudhari, Fred Zhao (as part of the AMRE 2020; The College of Wooster, Tree Ring Lab)

The aim of this study was to analyze White oak trees, to see how old they are and, how they are responding to the wetter and warming climate in Wooster, OH.

Kinney Field, Wooster, OH.

The AMRE_Tree Ring Team 2020 is pictured above.

Kinney Field, located in Wooster, OH has long served as a recreational location for various sports and a nice place for public entertainment. On its southwest corner are several old white oaks making it an ideal destination for tree-ring research. The geological setting is an Ice Age kame (hill) left by the retreating Laurentide Ice Sheet approximately 15,000 years ago.  The hill on which the trees grow is thus a well-drained feature built of permeable sediments, likely sand and gravel. We set out to determine the age of the trees, build a tree-ring chronology from the ring-widths, and compare the ring-width series with the monthly meteorological observations recorded at Wooster’s OARDC since C.E. 1888. This helps us better understand how this important tree species is reacting to a changing climate.

Bottom line: Nineteen cores were taken from 11 trees and processed at The College of Wooster Tree Ring Lab. We found that the White Oaks (Quercus alba) growing in the Kinney Field are positively correlated with precipitation in the April, May, June, and July months and have a strong negative correlation with June temperature.

Methods: Nineteen 5-mm diameter tree cores from were collected from 11 trees (Table 1) and, combined to produce a ring-width tree-ring chronology (Figure 2) at the Kinney Fields site, in Wooster, OH (Figure 1). The samples were cross dated in The College of Wooster Tree Ring Laboratory (WTRL) and were measured to the nearest 0.001 mm. This was then statistically cross-dated using the COFECHA (Holmes, 1983) software, and the chronology was then standardized using the ARSTAN software (Cook et al. 1985). The final chronology is made up of 19 cores from 11 trees with a mean series intercorrelation of 0.66 and an average mean sensitivity of 0.24 (Table 2). We used the raw data for the final chronology and point out the upward increasing trend in the series (Figure 2).

Fig. 1: Map showing study site at Kinney Field, Wooster, OH. 

The monthly temperature (1894 to 2019) and precipitation (1888 to 2019) for Wooster Ohio taken at the OARDC data was acquired from the Global Historical Climatology Network (GHCN). The mean annual temperature was 9.8ºC and the average annual precipitation was 947 mm during this time period. The months with the highest precipitation for 1888 to 2019 were June and July, and the highest temperature during the years 1894 to 2019 were June, July, and August. The months with the lowest temperatures were January and February (Figure 3).

The team coring a White Oak.

Measuring tree cores from Kinney Field in the Lab.

Fig. 2: The raw ring width series for the Oaks at Kinney Field, Wooster, OH.

Fig. 3: Climograph showing the annual distribution of precipitation (1888 to 2019) and mean monthly temperature (1894 to 2019) for Wooster.

Fig. 4: Raw ring-widths correlated with monthly temperature records. Only the month of June is significant at the 0.05 level (the common interval is 1895-2019).

Fig. 5: Raw ring-width series correlated with monthly precipitation (1888-2019). The months of April-July are significant (p<0.05) and positive correlations.

Fig. 6: April-July total precipitation correlated with the raw ring width series with a correlation 0.57.

Discussion: The final ring width chronology is 200 years long from 1820 to 2019. The series intercorrelation is 0.66 whereas the mean sensitivity (measure of year to year variability) is 0.24. The series autocorrelation is 0.60 and is a measure of the persistence as it is when the chronology is correlated with itself. The mean ring width measurement is 4.25 mm, which is significantly high relative to other sites and implies that the trees have proper access to nutrients and there is little competition.  There is a strong positive correlation between the ring width and the precipitation in the months of April through July, and the trendlines for both closely follow each other throughout the chronology ( Figures 5, 6). Therefore, we can gather that the trees are tracking the low frequency increase (last ~100 year rise) in precipitation of the region and are also a good indicator of year to year April – July precipitation records in Wooster, OH. The correlation with monthly temperatures is only significantly negatively correlated with June temperature (Figure 4).  The correlation with June is -0.35 (Figure 5) is likely attributed to the high rates of evapotranspiration in the summer months, which can have negative impact on tree growth.

Conclusions:
1. The Kinney oaks are all less than about 200 years old and are therefore likely second growth;
2. The raw ring-width data from 19 tree cores has an upward trend strongly correlated with total April through July precipitation measured at the OARDC since 1888;
3. The negative correlation of -0.35 of raw ring width and June temperature is due to increased evapotranspiration demand during warm Junes.

Acknowledgements:
This work is supported by the Sherman-Fairchild Foundation and the Luce Foundation. We also thank the organizers of AMRE 2020. A special thanks to Melita Wiles for doing all the measuring, Pedro Oliboni for coring the trees and his help with R, and Corinne Wiles for making the blog entry. All three students worked on this project because they lived in the relocated Wooster Tree Ring Lab during the Summer of 2020. Thanks also to the organizers and directors of AMRE.

 

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New Paper on the Dawn Redwood (Metasequoia) Trees of Wooster Ohio

The Wooster Tree Ring Lab has just published a paper with Franklin and Marshall College and The Ohio State University on the climate response of the Dawn Redwood tree. The study site is the beautiful Secrest Arboretum at the OARDC – OSU Wooster Campus. The upshot is that these remarkable and fast-growing trees are clearly doing well and as long as the increase in precipitation that Northeast Ohio is receiving keeps pace with the summer warming they should continue to do well. Why not plant more of these beautiful trees as they thrive, sequester carbon, and provide many other ecosystem services.

The senior author is Lauren Vargo, who is now a glaciologist research scientist at the Antarctic Research Centre in Wellington, Australia. Lauren did much of this work while an undergraduate at Wooster. Lauren is also the recent lead author on this Nature Climate Change contribution. Great thanks to Lauren also for sharing here research this summer.

Here is the technical abstract of the Dawn Redwood paper:

ABSTRACT

Metasequoia glyptostroboides,a deciduous gymnosperm, also known as dawn redwood, was thought to be extinct until living members of the species were found in China in 1943. Analyzing the climate response of a transplanted stand of the trees can give insights into their physiological plasticity, into their use in restoration and reforestation, as well as into interpreting the environmental conditions of the geologic past from fossil Metasequoia. An annual ring-width chronology—spanning 1955 to 2010 and based on a stand of 19 M. glyptostroboides trees planted in Secrest Arboretum in northeast Ohio, USA—shows negative correlations with maximum monthly temperatures: with the strongest relationship with February and the warm months of June and July, all significant at the 99% confidence levels. A positive May to June precipitation correlation is the strongest moisture signal (p < 0.05) and the narrowest rings in the chronology occurred during the drought of 1987 to 1988, consistent with one of the warmest and driest Junes on record. These results have implications for the future as climate change affects the native and transplanted range of this species. Future response of this species to a changing climate will depend on the relative rates of warming maximum temperatures in the winter and summer, as well as changing moisture conditions during the summer months.

Figure above shows the tree-ring record from a stand of 19 Dawn Redwood trees (upper panel A). The lower blue and red graph (B) is the climate response of the trees – temperature (red bars) is strongly negatively correlated with summer (June and July) temperatures and with February temperature. The summer relationship makes sense as hot summers require higher evapotranspiration demands. The negative correlation with winter is hypothesized to be linked to warming winters leading to less snow cover leaving roots exposed and vulnerable to damaging frosts. This negative relationship may go away as warming continues and frosts become less frequent.

Figure above shows three photos of cores from Dawn Redwood – note the narrow 1988 drought ring (white dots). 

The College of Wooster Paleoclimate class mulls around the Dawn Redwood stand. 

Another great photo of  Dawn Redwoods – they are deciduous conifers so this photo in the early spring before growth.

Many thanks to the Secrest Arboretum for permission to core these impressive trees. We greatly appreciate the support of Jason Veil the Curator of the Arboretum.

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New paper on a symbiotic relationship between tube-dwellers and bryozoans in the Silurian of Estonia

I have thoroughly enjoyed my many expeditions to the wondrous Baltic country of Estonia. My Estonian colleagues are fabulous, and I’ve been privileged to share the adventures with numerous students and Bill Ausich of Ohio State. Now during this global pandemic Estonia may as well be on the far side of the Moon. Maybe someday in the New Normal such travel will be possible again.

In the meantime, Olev Vinn has led our small international team to a new paper published today in the journal Lethaia. It is part of a long-term project describing the evolution of symbiosis among marine invertebrates. The abstract follows —

AbstractCornulites sp. and Fistulipora przhidolensis formed a symbiotic association in the Pridoli (latest Silurian) of Saaremaa Island, Estonia. This Cornulites sp.–F. przhidolensis association is the youngest example of cornulitid–bryozoan symbiosis. Symbiosis is indicated by intergrowth of both organisms. The cornulitids are completely embedded within the cystoporate bryozoan colony, leaving only their apertures free on the growth surface of the bryozoan. In terms of food competition, this association could have been slightly harmful to F. przhidolensis as Cornulites sp. may have been a kleptoparasite. There may have been a small escalation in the evolution of the endobiotic life mode of cornulitids as the number of such associations increased from the Ordovician to Silurian. It is likely that Palaeozoic bryozoan symbiosis reached its maximum in the Late Ordovician. Most of the symbiotic bryozoans in the Palaeozoic are trepostomes, and the diversity of symbiotic associations was also greatest among trepostomes.

The image above is Figure 2 from the paper. Caption: Cornulites sp. intergrown with Fistulipora przhidolensis from the lower Pridoli (Kaugatuma Formation) of Lõo cliff, Saaremaa, Estonia (GIT 666‐38). A, detailed view of bryozoan, B, Cornulites sp. [Corn] in cross section, C, D, apertures of Cornulites sp. [Corn] on the growth surface of Fistulipora.

If anyone wants a pdf, just send me an email.

Reference:

Vinn, O., Ernst, A., Wilson, M.A. and Toom, U. 2020. Symbiosis of cornulitids with the cystoporate bryozoan Fistulipora in the Pridoli of Saaremaa, Estonia. Lethaia (https:// doi.org/10.1111/let.12385).

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Let’s celebrate Earth Day!

Happy Earth Day, everyone! Although we can’t all be together this Earth Day, we’re still celebrating wherever we are. We hope you’ll join us in celebrating, too. Check out the video below, which tells you what some of our students and faculty are doing!

 

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New Paper on Antarctic Storm Wave Generation

I was part of a team led by Momme Hell at Scripps Institution for Oceanography that recently published an article in the Journal of Geophysical Research Oceans entitled: “Estimating Southern Ocean Storm Positions With Seismic Observations”. Momme is an expert in detecting seismic waves. We often hear about seismic waves in relation to earthquakes, but on an ice shelf (which is floating on the ocean), the surface also moves up and down with ocean waves.

The reason why Momme brought me on this project was because: 1) storm events are an important generation mechanism for these waves, and 2) I developed an algorithm for detecting and tracking storms from atmospheric data (i.e., atmospheric reanalyses). We wanted to know how well the storms detected from the atmospheric renalsyses aligned with the seismic observations that Momme makes.

The tracks of 2827 storms used in this study. These are on the Pacific-side of Antarctica — including the Ross, Amundsen, and Bellingshausen Seas. Many of the same storms passed by Thwaites and Dotson, Ice Shelves, where Dr. Alley was in Nov 2019 – Jan 2020.

The answer? Not nearly as well as we’d like. Only about 45% of the observations in the reanalyses and seismics align with each other. Some of that error is  from the imperfect relationship between seismic observations and wave-generation by storms, but another reason for error is our imperfect satellite observations of storm systems. The Southern Ocean has some of the sparsest atmospheric observations in the world, and the presence of ample sea ice complicates detection. For example, it’s difficult to distinguish between ice crystals in clouds and the snow/sea ice surface below. In other words, NOAA and NASA and other agencies still have some work to do to perfect the science of weather observation.

An example of how seismic stations on the edge of the Ross Ice Shelf were used to detect the location of maximum wind propagation (orange line and red arrow), and how that compared to the storm track in the reanalysis data (black track with gray point as best match). Winds are typically strongest near but not at the very center of a storm, so this is an example of an ideal match. The dark gray blotch at the bottom is Antartica, and the lighter gray around it is the sea ice. The blue is wave heights (darker blue = bigger waves.)


Here is the plain language summary:
“Surface winds under storms over the Southern Ocean make large ocean waves that travel over long distances (>1,000 km). Regions of wave generation coincide with regions where ocean uptake of heat and CO2 is large, so knowledge about wave generation regions helps us to understand the role of the Southern Ocean in the climate system. A 2‐year field campaign made new observations of ocean wave arrivals at the Ross Ice Shelf. These observations are used to trace the origins of the wave events in the Southern Ocean. Even though the waves observed in the sea ice are much smaller than in the open ocean, the observations are good enough to identify ocean waves. The wave arrivals can be used to infer a most likely time and location of the storm that generated the waves. Comparison with two reanalysis products (Modern‐Era Retrospective Analysis for Research and Applications, Version 2, and ERA5) suggests that more than half of the observed ocean wave events cannot be matched to individual Southern Ocean storms. This high percentage of displaced storms in the reanalysis products can be explained by the limited availability of satellite observations caused by the presence of sea ice.”

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